2cos (problem 3.3.5)

Percentage Accurate: 37.6% → 99.5%
Time: 19.0s
Alternatives: 15
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 15 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 37.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Alternative 1: 99.5% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\frac{\sin \varepsilon}{-1} \cdot \tan \left(\frac{\varepsilon}{2}\right)\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (fma
  (sin x)
  (- (sin eps))
  (* (cos x) (* (/ (sin eps) -1.0) (tan (/ eps 2.0))))))
double code(double x, double eps) {
	return fma(sin(x), -sin(eps), (cos(x) * ((sin(eps) / -1.0) * tan((eps / 2.0)))));
}
function code(x, eps)
	return fma(sin(x), Float64(-sin(eps)), Float64(cos(x) * Float64(Float64(sin(eps) / -1.0) * tan(Float64(eps / 2.0)))))
end
code[x_, eps_] := N[(N[Sin[x], $MachinePrecision] * (-N[Sin[eps], $MachinePrecision]) + N[(N[Cos[x], $MachinePrecision] * N[(N[(N[Sin[eps], $MachinePrecision] / -1.0), $MachinePrecision] * N[Tan[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\frac{\sin \varepsilon}{-1} \cdot \tan \left(\frac{\varepsilon}{2}\right)\right)\right)
\end{array}
Derivation
  1. Initial program 33.0%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. cos-sum60.6%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
    2. cancel-sign-sub-inv60.6%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. fma-def60.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
  3. Applied egg-rr60.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
  4. Taylor expanded in x around inf 60.6%

    \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
  5. Step-by-step derivation
    1. neg-mul-160.6%

      \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
    2. distribute-lft-neg-in60.6%

      \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
    3. associate--l+87.7%

      \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
    4. distribute-lft-neg-in87.7%

      \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
    5. distribute-rgt-neg-in87.7%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
    6. *-commutative87.7%

      \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
    7. fma-def87.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
    8. *-rgt-identity87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
    9. distribute-lft-out--87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
    10. sub-neg87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
    11. metadata-eval87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
    12. +-commutative87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
  6. Simplified87.7%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
  7. Step-by-step derivation
    1. flip-+87.4%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{-1 \cdot -1 - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}}\right) \]
    2. metadata-eval87.4%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{1} - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}\right) \]
  8. Applied egg-rr87.4%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{1 - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}}\right) \]
  9. Step-by-step derivation
    1. 1-sub-cos99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{\sin \varepsilon \cdot \sin \varepsilon}}{-1 - \cos \varepsilon}\right) \]
  10. Simplified99.2%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{\sin \varepsilon \cdot \sin \varepsilon}{-1 - \cos \varepsilon}}\right) \]
  11. Taylor expanded in eps around inf 99.2%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 \cdot \frac{{\sin \varepsilon}^{2}}{1 + \cos \varepsilon}\right)}\right) \]
  12. Step-by-step derivation
    1. metadata-eval99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\color{blue}{\frac{1}{-1}} \cdot \frac{{\sin \varepsilon}^{2}}{1 + \cos \varepsilon}\right)\right) \]
    2. times-frac99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{1 \cdot {\sin \varepsilon}^{2}}{-1 \cdot \left(1 + \cos \varepsilon\right)}}\right) \]
    3. *-lft-identity99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{{\sin \varepsilon}^{2}}}{-1 \cdot \left(1 + \cos \varepsilon\right)}\right) \]
    4. unpow299.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{\sin \varepsilon \cdot \sin \varepsilon}}{-1 \cdot \left(1 + \cos \varepsilon\right)}\right) \]
    5. times-frac99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\frac{\sin \varepsilon}{-1} \cdot \frac{\sin \varepsilon}{1 + \cos \varepsilon}\right)}\right) \]
    6. hang-0p-tan99.5%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\frac{\sin \varepsilon}{-1} \cdot \color{blue}{\tan \left(\frac{\varepsilon}{2}\right)}\right)\right) \]
  13. Simplified99.5%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\frac{\sin \varepsilon}{-1} \cdot \tan \left(\frac{\varepsilon}{2}\right)\right)}\right) \]
  14. Final simplification99.5%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\frac{\sin \varepsilon}{-1} \cdot \tan \left(\frac{\varepsilon}{2}\right)\right)\right) \]

Alternative 2: 99.0% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2} - \sin x \cdot \sin \varepsilon \end{array} \]
(FPCore (x eps)
 :precision binary64
 (-
  (* (/ (cos x) (- -1.0 (cos eps))) (pow (sin eps) 2.0))
  (* (sin x) (sin eps))))
double code(double x, double eps) {
	return ((cos(x) / (-1.0 - cos(eps))) * pow(sin(eps), 2.0)) - (sin(x) * sin(eps));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = ((cos(x) / ((-1.0d0) - cos(eps))) * (sin(eps) ** 2.0d0)) - (sin(x) * sin(eps))
end function
public static double code(double x, double eps) {
	return ((Math.cos(x) / (-1.0 - Math.cos(eps))) * Math.pow(Math.sin(eps), 2.0)) - (Math.sin(x) * Math.sin(eps));
}
def code(x, eps):
	return ((math.cos(x) / (-1.0 - math.cos(eps))) * math.pow(math.sin(eps), 2.0)) - (math.sin(x) * math.sin(eps))
function code(x, eps)
	return Float64(Float64(Float64(cos(x) / Float64(-1.0 - cos(eps))) * (sin(eps) ^ 2.0)) - Float64(sin(x) * sin(eps)))
end
function tmp = code(x, eps)
	tmp = ((cos(x) / (-1.0 - cos(eps))) * (sin(eps) ^ 2.0)) - (sin(x) * sin(eps));
end
code[x_, eps_] := N[(N[(N[(N[Cos[x], $MachinePrecision] / N[(-1.0 - N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Power[N[Sin[eps], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2} - \sin x \cdot \sin \varepsilon
\end{array}
Derivation
  1. Initial program 33.0%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. cos-sum60.6%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
    2. cancel-sign-sub-inv60.6%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. fma-def60.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
  3. Applied egg-rr60.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
  4. Taylor expanded in x around inf 60.6%

    \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
  5. Step-by-step derivation
    1. neg-mul-160.6%

      \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
    2. distribute-lft-neg-in60.6%

      \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
    3. associate--l+87.7%

      \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
    4. distribute-lft-neg-in87.7%

      \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
    5. distribute-rgt-neg-in87.7%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
    6. *-commutative87.7%

      \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
    7. fma-def87.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
    8. *-rgt-identity87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
    9. distribute-lft-out--87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
    10. sub-neg87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
    11. metadata-eval87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
    12. +-commutative87.7%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
  6. Simplified87.7%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
  7. Step-by-step derivation
    1. flip-+87.4%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{-1 \cdot -1 - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}}\right) \]
    2. metadata-eval87.4%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{1} - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}\right) \]
  8. Applied egg-rr87.4%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{1 - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}}\right) \]
  9. Step-by-step derivation
    1. 1-sub-cos99.2%

      \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \frac{\color{blue}{\sin \varepsilon \cdot \sin \varepsilon}}{-1 - \cos \varepsilon}\right) \]
  10. Simplified99.2%

    \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\frac{\sin \varepsilon \cdot \sin \varepsilon}{-1 - \cos \varepsilon}}\right) \]
  11. Step-by-step derivation
    1. fma-udef99.2%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right) + \cos x \cdot \frac{\sin \varepsilon \cdot \sin \varepsilon}{-1 - \cos \varepsilon}} \]
    2. associate-*r/99.2%

      \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \color{blue}{\frac{\cos x \cdot \left(\sin \varepsilon \cdot \sin \varepsilon\right)}{-1 - \cos \varepsilon}} \]
    3. pow299.2%

      \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \frac{\cos x \cdot \color{blue}{{\sin \varepsilon}^{2}}}{-1 - \cos \varepsilon} \]
  12. Applied egg-rr99.2%

    \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right) + \frac{\cos x \cdot {\sin \varepsilon}^{2}}{-1 - \cos \varepsilon}} \]
  13. Step-by-step derivation
    1. +-commutative99.2%

      \[\leadsto \color{blue}{\frac{\cos x \cdot {\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} + \sin x \cdot \left(-\sin \varepsilon\right)} \]
    2. distribute-rgt-neg-out99.2%

      \[\leadsto \frac{\cos x \cdot {\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} + \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} \]
    3. unsub-neg99.2%

      \[\leadsto \color{blue}{\frac{\cos x \cdot {\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} - \sin x \cdot \sin \varepsilon} \]
    4. associate-/l*99.1%

      \[\leadsto \color{blue}{\frac{\cos x}{\frac{-1 - \cos \varepsilon}{{\sin \varepsilon}^{2}}}} - \sin x \cdot \sin \varepsilon \]
    5. associate-/r/99.2%

      \[\leadsto \color{blue}{\frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2}} - \sin x \cdot \sin \varepsilon \]
    6. *-commutative99.2%

      \[\leadsto \frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2} - \color{blue}{\sin \varepsilon \cdot \sin x} \]
  14. Simplified99.2%

    \[\leadsto \color{blue}{\frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2} - \sin \varepsilon \cdot \sin x} \]
  15. Final simplification99.2%

    \[\leadsto \frac{\cos x}{-1 - \cos \varepsilon} \cdot {\sin \varepsilon}^{2} - \sin x \cdot \sin \varepsilon \]

Alternative 3: 99.1% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-5}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -4e-5)
   (- (fma (sin eps) (- (sin x)) (* (cos x) (cos eps))) (cos x))
   (if (<= eps 2.1e-5)
     (* -2.0 (* (+ (sin x) (* 0.5 (* eps (cos x)))) (sin (* eps 0.5))))
     (fma (cos x) (+ -1.0 (cos eps)) (* (sin x) (- (sin eps)))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -4e-5) {
		tmp = fma(sin(eps), -sin(x), (cos(x) * cos(eps))) - cos(x);
	} else if (eps <= 2.1e-5) {
		tmp = -2.0 * ((sin(x) + (0.5 * (eps * cos(x)))) * sin((eps * 0.5)));
	} else {
		tmp = fma(cos(x), (-1.0 + cos(eps)), (sin(x) * -sin(eps)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -4e-5)
		tmp = Float64(fma(sin(eps), Float64(-sin(x)), Float64(cos(x) * cos(eps))) - cos(x));
	elseif (eps <= 2.1e-5)
		tmp = Float64(-2.0 * Float64(Float64(sin(x) + Float64(0.5 * Float64(eps * cos(x)))) * sin(Float64(eps * 0.5))));
	else
		tmp = fma(cos(x), Float64(-1.0 + cos(eps)), Float64(sin(x) * Float64(-sin(eps))));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -4e-5], N[(N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision]) + N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 2.1e-5], N[(-2.0 * N[(N[(N[Sin[x], $MachinePrecision] + N[(0.5 * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[x], $MachinePrecision] * (-N[Sin[eps], $MachinePrecision])), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -4 \cdot 10^{-5}:\\
\;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-5}:\\
\;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -4.00000000000000033e-5

    1. Initial program 48.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.8%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. sub-neg98.8%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    3. Applied egg-rr98.8%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x \]
    4. Step-by-step derivation
      1. +-commutative98.8%

        \[\leadsto \color{blue}{\left(\left(-\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      2. distribute-lft-neg-in98.8%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      3. *-commutative98.8%

        \[\leadsto \left(\color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} + \cos x \cdot \cos \varepsilon\right) - \cos x \]
      4. fma-def98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right)} - \cos x \]
      5. *-commutative98.9%

        \[\leadsto \mathsf{fma}\left(\sin \varepsilon, -\sin x, \color{blue}{\cos \varepsilon \cdot \cos x}\right) - \cos x \]
    5. Simplified98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos \varepsilon \cdot \cos x\right)} - \cos x \]

    if -4.00000000000000033e-5 < eps < 2.09999999999999988e-5

    1. Initial program 20.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos43.2%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr43.2%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in98.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 99.7%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)}\right) \]

    if 2.09999999999999988e-5 < eps

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
      3. fma-def98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    4. Taylor expanded in x around inf 98.7%

      \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
    5. Step-by-step derivation
      1. neg-mul-198.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      2. distribute-lft-neg-in98.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      3. associate--l+98.8%

        \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
      4. distribute-lft-neg-in98.8%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      5. distribute-rgt-neg-in98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      6. *-commutative98.8%

        \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
      7. fma-def98.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
      8. *-rgt-identity98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
      9. distribute-lft-out--98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
      10. sub-neg98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
      11. metadata-eval98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
      12. +-commutative98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
    6. Simplified98.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
    7. Taylor expanded in x around inf 98.9%

      \[\leadsto \color{blue}{-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon - 1\right)} \]
    8. Step-by-step derivation
      1. sub-neg98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} \]
      2. metadata-eval98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) \]
      3. +-commutative98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} \]
      4. mul-1-neg98.9%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      5. distribute-rgt-neg-out98.9%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      6. +-commutative98.9%

        \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) + \sin x \cdot \left(-\sin \varepsilon\right)} \]
      7. fma-def99.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)} \]
      8. +-commutative99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \color{blue}{\cos \varepsilon + -1}, \sin x \cdot \left(-\sin \varepsilon\right)\right) \]
      9. distribute-rgt-neg-out99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{-\sin x \cdot \sin \varepsilon}\right) \]
      10. *-commutative99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, -\color{blue}{\sin \varepsilon \cdot \sin x}\right) \]
      11. distribute-rgt-neg-in99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)}\right) \]
    9. Simplified99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\sin \varepsilon, -\sin x, \cos x \cdot \cos \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-5}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \end{array} \]

Alternative 4: 99.1% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.6 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\cos x\right) - \sin x \cdot \sin \varepsilon\right)\\ \mathbf{elif}\;\varepsilon \leq 2.8 \cdot 10^{-5}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -7.6e-5)
   (fma (cos x) (cos eps) (- (- (cos x)) (* (sin x) (sin eps))))
   (if (<= eps 2.8e-5)
     (* -2.0 (* (+ (sin x) (* 0.5 (* eps (cos x)))) (sin (* eps 0.5))))
     (fma (cos x) (+ -1.0 (cos eps)) (* (sin x) (- (sin eps)))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -7.6e-5) {
		tmp = fma(cos(x), cos(eps), (-cos(x) - (sin(x) * sin(eps))));
	} else if (eps <= 2.8e-5) {
		tmp = -2.0 * ((sin(x) + (0.5 * (eps * cos(x)))) * sin((eps * 0.5)));
	} else {
		tmp = fma(cos(x), (-1.0 + cos(eps)), (sin(x) * -sin(eps)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -7.6e-5)
		tmp = fma(cos(x), cos(eps), Float64(Float64(-cos(x)) - Float64(sin(x) * sin(eps))));
	elseif (eps <= 2.8e-5)
		tmp = Float64(-2.0 * Float64(Float64(sin(x) + Float64(0.5 * Float64(eps * cos(x)))) * sin(Float64(eps * 0.5))));
	else
		tmp = fma(cos(x), Float64(-1.0 + cos(eps)), Float64(sin(x) * Float64(-sin(eps))));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -7.6e-5], N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[((-N[Cos[x], $MachinePrecision]) - N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 2.8e-5], N[(-2.0 * N[(N[(N[Sin[x], $MachinePrecision] + N[(0.5 * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[x], $MachinePrecision] * (-N[Sin[eps], $MachinePrecision])), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -7.6 \cdot 10^{-5}:\\
\;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\cos x\right) - \sin x \cdot \sin \varepsilon\right)\\

\mathbf{elif}\;\varepsilon \leq 2.8 \cdot 10^{-5}:\\
\;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -7.6000000000000004e-5

    1. Initial program 48.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg48.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.8%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.8%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]

    if -7.6000000000000004e-5 < eps < 2.79999999999999996e-5

    1. Initial program 20.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos43.2%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr43.2%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in98.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 99.7%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)}\right) \]

    if 2.79999999999999996e-5 < eps

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
      3. fma-def98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    4. Taylor expanded in x around inf 98.7%

      \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
    5. Step-by-step derivation
      1. neg-mul-198.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      2. distribute-lft-neg-in98.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      3. associate--l+98.8%

        \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
      4. distribute-lft-neg-in98.8%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      5. distribute-rgt-neg-in98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      6. *-commutative98.8%

        \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
      7. fma-def98.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
      8. *-rgt-identity98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
      9. distribute-lft-out--98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
      10. sub-neg98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
      11. metadata-eval98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
      12. +-commutative98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
    6. Simplified98.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
    7. Taylor expanded in x around inf 98.9%

      \[\leadsto \color{blue}{-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon - 1\right)} \]
    8. Step-by-step derivation
      1. sub-neg98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} \]
      2. metadata-eval98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) \]
      3. +-commutative98.9%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} \]
      4. mul-1-neg98.9%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      5. distribute-rgt-neg-out98.9%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      6. +-commutative98.9%

        \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) + \sin x \cdot \left(-\sin \varepsilon\right)} \]
      7. fma-def99.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)} \]
      8. +-commutative99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \color{blue}{\cos \varepsilon + -1}, \sin x \cdot \left(-\sin \varepsilon\right)\right) \]
      9. distribute-rgt-neg-out99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{-\sin x \cdot \sin \varepsilon}\right) \]
      10. *-commutative99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, -\color{blue}{\sin \varepsilon \cdot \sin x}\right) \]
      11. distribute-rgt-neg-in99.0%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)}\right) \]
    9. Simplified99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.6 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\cos x\right) - \sin x \cdot \sin \varepsilon\right)\\ \mathbf{elif}\;\varepsilon \leq 2.8 \cdot 10^{-5}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \end{array} \]

Alternative 5: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-5}\right):\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -2.7e-5) (not (<= eps 2.7e-5)))
   (fma (cos x) (+ -1.0 (cos eps)) (* (sin x) (- (sin eps))))
   (* -2.0 (* (+ (sin x) (* 0.5 (* eps (cos x)))) (sin (* eps 0.5))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.7e-5) || !(eps <= 2.7e-5)) {
		tmp = fma(cos(x), (-1.0 + cos(eps)), (sin(x) * -sin(eps)));
	} else {
		tmp = -2.0 * ((sin(x) + (0.5 * (eps * cos(x)))) * sin((eps * 0.5)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if ((eps <= -2.7e-5) || !(eps <= 2.7e-5))
		tmp = fma(cos(x), Float64(-1.0 + cos(eps)), Float64(sin(x) * Float64(-sin(eps))));
	else
		tmp = Float64(-2.0 * Float64(Float64(sin(x) + Float64(0.5 * Float64(eps * cos(x)))) * sin(Float64(eps * 0.5))));
	end
	return tmp
end
code[x_, eps_] := If[Or[LessEqual[eps, -2.7e-5], N[Not[LessEqual[eps, 2.7e-5]], $MachinePrecision]], N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[x], $MachinePrecision] * (-N[Sin[eps], $MachinePrecision])), $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[(N[(N[Sin[x], $MachinePrecision] + N[(0.5 * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-5}\right):\\
\;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.6999999999999999e-5 or 2.6999999999999999e-5 < eps

    1. Initial program 45.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
      3. fma-def98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    4. Taylor expanded in x around inf 98.7%

      \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
    5. Step-by-step derivation
      1. neg-mul-198.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      2. distribute-lft-neg-in98.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      3. associate--l+98.8%

        \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
      4. distribute-lft-neg-in98.8%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      5. distribute-rgt-neg-in98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      6. *-commutative98.8%

        \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
      7. fma-def98.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
      8. *-rgt-identity98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
      9. distribute-lft-out--98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
      10. sub-neg98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
      11. metadata-eval98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
      12. +-commutative98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
    6. Simplified98.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
    7. Taylor expanded in x around inf 98.8%

      \[\leadsto \color{blue}{-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon - 1\right)} \]
    8. Step-by-step derivation
      1. sub-neg98.8%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} \]
      2. metadata-eval98.8%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) \]
      3. +-commutative98.8%

        \[\leadsto -1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} \]
      4. mul-1-neg98.8%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      5. distribute-rgt-neg-out98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \cos x \cdot \left(-1 + \cos \varepsilon\right) \]
      6. +-commutative98.8%

        \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) + \sin x \cdot \left(-\sin \varepsilon\right)} \]
      7. fma-def98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)} \]
      8. +-commutative98.9%

        \[\leadsto \mathsf{fma}\left(\cos x, \color{blue}{\cos \varepsilon + -1}, \sin x \cdot \left(-\sin \varepsilon\right)\right) \]
      9. distribute-rgt-neg-out98.9%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{-\sin x \cdot \sin \varepsilon}\right) \]
      10. *-commutative98.9%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, -\color{blue}{\sin \varepsilon \cdot \sin x}\right) \]
      11. distribute-rgt-neg-in98.9%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)}\right) \]
    9. Simplified98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon + -1, \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]

    if -2.6999999999999999e-5 < eps < 2.6999999999999999e-5

    1. Initial program 20.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos43.2%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr43.2%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in98.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 99.7%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.7 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-5}\right):\\ \;\;\;\;\mathsf{fma}\left(\cos x, -1 + \cos \varepsilon, \sin x \cdot \left(-\sin \varepsilon\right)\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \]

Alternative 6: 99.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.05 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.75 \cdot 10^{-5}\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -2.05e-5) (not (<= eps 2.75e-5)))
   (- (* (cos x) (+ -1.0 (cos eps))) (* (sin x) (sin eps)))
   (* -2.0 (* (+ (sin x) (* 0.5 (* eps (cos x)))) (sin (* eps 0.5))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.05e-5) || !(eps <= 2.75e-5)) {
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(x) * sin(eps));
	} else {
		tmp = -2.0 * ((sin(x) + (0.5 * (eps * cos(x)))) * sin((eps * 0.5)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-2.05d-5)) .or. (.not. (eps <= 2.75d-5))) then
        tmp = (cos(x) * ((-1.0d0) + cos(eps))) - (sin(x) * sin(eps))
    else
        tmp = (-2.0d0) * ((sin(x) + (0.5d0 * (eps * cos(x)))) * sin((eps * 0.5d0)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -2.05e-5) || !(eps <= 2.75e-5)) {
		tmp = (Math.cos(x) * (-1.0 + Math.cos(eps))) - (Math.sin(x) * Math.sin(eps));
	} else {
		tmp = -2.0 * ((Math.sin(x) + (0.5 * (eps * Math.cos(x)))) * Math.sin((eps * 0.5)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -2.05e-5) or not (eps <= 2.75e-5):
		tmp = (math.cos(x) * (-1.0 + math.cos(eps))) - (math.sin(x) * math.sin(eps))
	else:
		tmp = -2.0 * ((math.sin(x) + (0.5 * (eps * math.cos(x)))) * math.sin((eps * 0.5)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -2.05e-5) || !(eps <= 2.75e-5))
		tmp = Float64(Float64(cos(x) * Float64(-1.0 + cos(eps))) - Float64(sin(x) * sin(eps)));
	else
		tmp = Float64(-2.0 * Float64(Float64(sin(x) + Float64(0.5 * Float64(eps * cos(x)))) * sin(Float64(eps * 0.5))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -2.05e-5) || ~((eps <= 2.75e-5)))
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(x) * sin(eps));
	else
		tmp = -2.0 * ((sin(x) + (0.5 * (eps * cos(x)))) * sin((eps * 0.5)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -2.05e-5], N[Not[LessEqual[eps, 2.75e-5]], $MachinePrecision]], N[(N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[(N[(N[Sin[x], $MachinePrecision] + N[(0.5 * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -2.05 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.75 \cdot 10^{-5}\right):\\
\;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.05000000000000002e-5 or 2.7500000000000001e-5 < eps

    1. Initial program 45.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
      3. fma-def98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    4. Taylor expanded in x around inf 98.7%

      \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin x \cdot \sin \varepsilon\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
    5. Step-by-step derivation
      1. neg-mul-198.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      2. distribute-lft-neg-in98.7%

        \[\leadsto \left(\color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon} + \cos \varepsilon \cdot \cos x\right) - \cos x \]
      3. associate--l+98.8%

        \[\leadsto \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon + \left(\cos \varepsilon \cdot \cos x - \cos x\right)} \]
      4. distribute-lft-neg-in98.8%

        \[\leadsto \color{blue}{\left(-\sin x \cdot \sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      5. distribute-rgt-neg-in98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right)} + \left(\cos \varepsilon \cdot \cos x - \cos x\right) \]
      6. *-commutative98.8%

        \[\leadsto \sin x \cdot \left(-\sin \varepsilon\right) + \left(\color{blue}{\cos x \cdot \cos \varepsilon} - \cos x\right) \]
      7. fma-def98.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \cos x\right)} \]
      8. *-rgt-identity98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \cos \varepsilon - \color{blue}{\cos x \cdot 1}\right) \]
      9. distribute-lft-out--98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)}\right) \]
      10. sub-neg98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)}\right) \]
      11. metadata-eval98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right)\right) \]
      12. +-commutative98.8%

        \[\leadsto \mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)}\right) \]
    6. Simplified98.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, -\sin \varepsilon, \cos x \cdot \left(-1 + \cos \varepsilon\right)\right)} \]
    7. Step-by-step derivation
      1. fma-udef98.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right) + \cos x \cdot \left(-1 + \cos \varepsilon\right)} \]
    8. Applied egg-rr98.8%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\sin \varepsilon\right) + \cos x \cdot \left(-1 + \cos \varepsilon\right)} \]

    if -2.05000000000000002e-5 < eps < 2.7500000000000001e-5

    1. Initial program 20.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos43.2%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval43.2%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr43.2%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative43.2%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in98.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative98.8%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 99.7%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + \sin x\right)}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2.05 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.75 \cdot 10^{-5}\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \left(\left(\sin x + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \]

Alternative 7: 65.9% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\cos \left(x + \varepsilon\right) - \cos x \leq -1 \cdot 10^{-12}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= (- (cos (+ x eps)) (cos x)) -1e-12)
   (- (cos eps) (cos x))
   (* (sin x) (- eps))))
double code(double x, double eps) {
	double tmp;
	if ((cos((x + eps)) - cos(x)) <= -1e-12) {
		tmp = cos(eps) - cos(x);
	} else {
		tmp = sin(x) * -eps;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((cos((x + eps)) - cos(x)) <= (-1d-12)) then
        tmp = cos(eps) - cos(x)
    else
        tmp = sin(x) * -eps
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((Math.cos((x + eps)) - Math.cos(x)) <= -1e-12) {
		tmp = Math.cos(eps) - Math.cos(x);
	} else {
		tmp = Math.sin(x) * -eps;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (math.cos((x + eps)) - math.cos(x)) <= -1e-12:
		tmp = math.cos(eps) - math.cos(x)
	else:
		tmp = math.sin(x) * -eps
	return tmp
function code(x, eps)
	tmp = 0.0
	if (Float64(cos(Float64(x + eps)) - cos(x)) <= -1e-12)
		tmp = Float64(cos(eps) - cos(x));
	else
		tmp = Float64(sin(x) * Float64(-eps));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((cos((x + eps)) - cos(x)) <= -1e-12)
		tmp = cos(eps) - cos(x);
	else
		tmp = sin(x) * -eps;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], -1e-12], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\cos \left(x + \varepsilon\right) - \cos x \leq -1 \cdot 10^{-12}:\\
\;\;\;\;\cos \varepsilon - \cos x\\

\mathbf{else}:\\
\;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (cos.f64 (+.f64 x eps)) (cos.f64 x)) < -9.9999999999999998e-13

    1. Initial program 72.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 73.0%

      \[\leadsto \color{blue}{\cos \varepsilon} - \cos x \]

    if -9.9999999999999998e-13 < (-.f64 (cos.f64 (+.f64 x eps)) (cos.f64 x))

    1. Initial program 16.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 54.6%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*54.6%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg54.6%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified54.6%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification60.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\cos \left(x + \varepsilon\right) - \cos x \leq -1 \cdot 10^{-12}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \end{array} \]

Alternative 8: 77.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -200 \lor \neg \left(\varepsilon \leq 165000\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \sin x \cdot \varepsilon\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -200.0) (not (<= eps 165000.0)))
   (- (cos eps) (cos x))
   (- (* -0.5 (* eps (* eps (cos x)))) (* (sin x) eps))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -200.0) || !(eps <= 165000.0)) {
		tmp = cos(eps) - cos(x);
	} else {
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (sin(x) * eps);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-200.0d0)) .or. (.not. (eps <= 165000.0d0))) then
        tmp = cos(eps) - cos(x)
    else
        tmp = ((-0.5d0) * (eps * (eps * cos(x)))) - (sin(x) * eps)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -200.0) || !(eps <= 165000.0)) {
		tmp = Math.cos(eps) - Math.cos(x);
	} else {
		tmp = (-0.5 * (eps * (eps * Math.cos(x)))) - (Math.sin(x) * eps);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -200.0) or not (eps <= 165000.0):
		tmp = math.cos(eps) - math.cos(x)
	else:
		tmp = (-0.5 * (eps * (eps * math.cos(x)))) - (math.sin(x) * eps)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -200.0) || !(eps <= 165000.0))
		tmp = Float64(cos(eps) - cos(x));
	else
		tmp = Float64(Float64(-0.5 * Float64(eps * Float64(eps * cos(x)))) - Float64(sin(x) * eps));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -200.0) || ~((eps <= 165000.0)))
		tmp = cos(eps) - cos(x);
	else
		tmp = (-0.5 * (eps * (eps * cos(x)))) - (sin(x) * eps);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -200.0], N[Not[LessEqual[eps, 165000.0]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(eps * N[(eps * N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[x], $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -200 \lor \neg \left(\varepsilon \leq 165000\right):\\
\;\;\;\;\cos \varepsilon - \cos x\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \sin x \cdot \varepsilon\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -200 or 165000 < eps

    1. Initial program 47.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 49.0%

      \[\leadsto \color{blue}{\cos \varepsilon} - \cos x \]

    if -200 < eps < 165000

    1. Initial program 19.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 97.0%

      \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg97.0%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      2. unsub-neg97.0%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      3. unpow297.0%

        \[\leadsto -0.5 \cdot \left(\color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \cdot \cos x\right) - \varepsilon \cdot \sin x \]
      4. associate-*l*97.0%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right)} - \varepsilon \cdot \sin x \]
    4. Simplified97.0%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \varepsilon \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification73.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -200 \lor \neg \left(\varepsilon \leq 165000\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(\varepsilon \cdot \cos x\right)\right) - \sin x \cdot \varepsilon\\ \end{array} \]

Alternative 9: 76.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon - x \cdot -2\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* -2.0 (* (sin (* 0.5 (- eps (* x -2.0)))) (sin (* eps 0.5)))))
double code(double x, double eps) {
	return -2.0 * (sin((0.5 * (eps - (x * -2.0)))) * sin((eps * 0.5)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-2.0d0) * (sin((0.5d0 * (eps - (x * (-2.0d0))))) * sin((eps * 0.5d0)))
end function
public static double code(double x, double eps) {
	return -2.0 * (Math.sin((0.5 * (eps - (x * -2.0)))) * Math.sin((eps * 0.5)));
}
def code(x, eps):
	return -2.0 * (math.sin((0.5 * (eps - (x * -2.0)))) * math.sin((eps * 0.5)))
function code(x, eps)
	return Float64(-2.0 * Float64(sin(Float64(0.5 * Float64(eps - Float64(x * -2.0)))) * sin(Float64(eps * 0.5))))
end
function tmp = code(x, eps)
	tmp = -2.0 * (sin((0.5 * (eps - (x * -2.0)))) * sin((eps * 0.5)));
end
code[x_, eps_] := N[(-2.0 * N[(N[Sin[N[(0.5 * N[(eps - N[(x * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon - x \cdot -2\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)
\end{array}
Derivation
  1. Initial program 33.0%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. diff-cos43.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv43.3%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. metadata-eval43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. div-inv43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    5. +-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    6. metadata-eval43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  3. Applied egg-rr43.3%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
  4. Step-by-step derivation
    1. *-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    2. +-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    3. associate--l+72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    4. +-inverses72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    5. distribute-lft-in72.0%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    6. metadata-eval72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    7. *-commutative72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
    8. +-commutative72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
  5. Simplified72.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
  6. Taylor expanded in x around -inf 72.0%

    \[\leadsto -2 \cdot \color{blue}{\left(\sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)} \]
  7. Final simplification72.0%

    \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon - x \cdot -2\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]

Alternative 10: 76.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* -2.0 (* (sin (* 0.5 (+ x (+ x eps)))) (sin (* eps 0.5)))))
double code(double x, double eps) {
	return -2.0 * (sin((0.5 * (x + (x + eps)))) * sin((eps * 0.5)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-2.0d0) * (sin((0.5d0 * (x + (x + eps)))) * sin((eps * 0.5d0)))
end function
public static double code(double x, double eps) {
	return -2.0 * (Math.sin((0.5 * (x + (x + eps)))) * Math.sin((eps * 0.5)));
}
def code(x, eps):
	return -2.0 * (math.sin((0.5 * (x + (x + eps)))) * math.sin((eps * 0.5)))
function code(x, eps)
	return Float64(-2.0 * Float64(sin(Float64(0.5 * Float64(x + Float64(x + eps)))) * sin(Float64(eps * 0.5))))
end
function tmp = code(x, eps)
	tmp = -2.0 * (sin((0.5 * (x + (x + eps)))) * sin((eps * 0.5)));
end
code[x_, eps_] := N[(-2.0 * N[(N[Sin[N[(0.5 * N[(x + N[(x + eps), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)
\end{array}
Derivation
  1. Initial program 33.0%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. diff-cos43.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv43.3%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. metadata-eval43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. div-inv43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    5. +-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    6. metadata-eval43.3%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  3. Applied egg-rr43.3%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
  4. Step-by-step derivation
    1. *-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    2. +-commutative43.3%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    3. associate--l+72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    4. +-inverses72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    5. distribute-lft-in72.0%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    6. metadata-eval72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    7. *-commutative72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
    8. +-commutative72.0%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
  5. Simplified72.0%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
  6. Step-by-step derivation
    1. add-exp-log50.2%

      \[\leadsto -2 \cdot \color{blue}{e^{\log \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)}} \]
    2. *-commutative50.2%

      \[\leadsto -2 \cdot e^{\log \color{blue}{\left(\sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon + 0\right)\right)}} \]
    3. +-commutative50.2%

      \[\leadsto -2 \cdot e^{\log \left(\sin \left(0.5 \cdot \left(x + \color{blue}{\left(x + \varepsilon\right)}\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon + 0\right)\right)} \]
    4. +-rgt-identity50.2%

      \[\leadsto -2 \cdot e^{\log \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \color{blue}{\left(0.5 \cdot \varepsilon\right)}\right)} \]
  7. Applied egg-rr50.2%

    \[\leadsto -2 \cdot \color{blue}{e^{\log \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)}} \]
  8. Step-by-step derivation
    1. add-exp-log72.0%

      \[\leadsto -2 \cdot \color{blue}{\left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)} \]
    2. *-un-lft-identity72.0%

      \[\leadsto -2 \cdot \color{blue}{\left(1 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)\right)} \]
    3. +-commutative72.0%

      \[\leadsto -2 \cdot \left(1 \cdot \left(\sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)\right) \]
    4. *-commutative72.0%

      \[\leadsto -2 \cdot \left(1 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right) \cdot \sin \color{blue}{\left(\varepsilon \cdot 0.5\right)}\right)\right) \]
  9. Applied egg-rr72.0%

    \[\leadsto -2 \cdot \color{blue}{\left(1 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\right)} \]
  10. Step-by-step derivation
    1. *-lft-identity72.0%

      \[\leadsto -2 \cdot \color{blue}{\left(\sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    2. *-commutative72.0%

      \[\leadsto -2 \cdot \color{blue}{\left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
  11. Simplified72.0%

    \[\leadsto -2 \cdot \color{blue}{\left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
  12. Final simplification72.0%

    \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]

Alternative 11: 70.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\ \mathbf{if}\;x \leq -2.65 \cdot 10^{-51} \lor \neg \left(x \leq 6.2 \cdot 10^{-26}\right):\\ \;\;\;\;-2 \cdot \left(\sin x \cdot t_0\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot {t_0}^{2}\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (sin (* eps 0.5))))
   (if (or (<= x -2.65e-51) (not (<= x 6.2e-26)))
     (* -2.0 (* (sin x) t_0))
     (* -2.0 (pow t_0 2.0)))))
double code(double x, double eps) {
	double t_0 = sin((eps * 0.5));
	double tmp;
	if ((x <= -2.65e-51) || !(x <= 6.2e-26)) {
		tmp = -2.0 * (sin(x) * t_0);
	} else {
		tmp = -2.0 * pow(t_0, 2.0);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sin((eps * 0.5d0))
    if ((x <= (-2.65d-51)) .or. (.not. (x <= 6.2d-26))) then
        tmp = (-2.0d0) * (sin(x) * t_0)
    else
        tmp = (-2.0d0) * (t_0 ** 2.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.sin((eps * 0.5));
	double tmp;
	if ((x <= -2.65e-51) || !(x <= 6.2e-26)) {
		tmp = -2.0 * (Math.sin(x) * t_0);
	} else {
		tmp = -2.0 * Math.pow(t_0, 2.0);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.sin((eps * 0.5))
	tmp = 0
	if (x <= -2.65e-51) or not (x <= 6.2e-26):
		tmp = -2.0 * (math.sin(x) * t_0)
	else:
		tmp = -2.0 * math.pow(t_0, 2.0)
	return tmp
function code(x, eps)
	t_0 = sin(Float64(eps * 0.5))
	tmp = 0.0
	if ((x <= -2.65e-51) || !(x <= 6.2e-26))
		tmp = Float64(-2.0 * Float64(sin(x) * t_0));
	else
		tmp = Float64(-2.0 * (t_0 ^ 2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = sin((eps * 0.5));
	tmp = 0.0;
	if ((x <= -2.65e-51) || ~((x <= 6.2e-26)))
		tmp = -2.0 * (sin(x) * t_0);
	else
		tmp = -2.0 * (t_0 ^ 2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]}, If[Or[LessEqual[x, -2.65e-51], N[Not[LessEqual[x, 6.2e-26]], $MachinePrecision]], N[(-2.0 * N[(N[Sin[x], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[Power[t$95$0, 2.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\
\mathbf{if}\;x \leq -2.65 \cdot 10^{-51} \lor \neg \left(x \leq 6.2 \cdot 10^{-26}\right):\\
\;\;\;\;-2 \cdot \left(\sin x \cdot t_0\right)\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot {t_0}^{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -2.64999999999999987e-51 or 6.19999999999999966e-26 < x

    1. Initial program 12.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos10.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv10.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval10.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv10.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative10.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval10.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr10.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative10.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative10.7%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+54.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses54.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in54.4%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval54.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative54.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative54.4%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified54.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 51.4%

      \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \color{blue}{\sin x}\right) \]

    if -2.64999999999999987e-51 < x < 6.19999999999999966e-26

    1. Initial program 65.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos94.3%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv94.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr94.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in99.6%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified99.6%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in x around 0 92.4%

      \[\leadsto -2 \cdot \color{blue}{{\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -2.65 \cdot 10^{-51} \lor \neg \left(x \leq 6.2 \cdot 10^{-26}\right):\\ \;\;\;\;-2 \cdot \left(\sin x \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \end{array} \]

Alternative 12: 68.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -4.6 \cdot 10^{-52} \lor \neg \left(x \leq 7.2 \cdot 10^{-27}\right):\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= x -4.6e-52) (not (<= x 7.2e-27)))
   (* (sin x) (- eps))
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))))
double code(double x, double eps) {
	double tmp;
	if ((x <= -4.6e-52) || !(x <= 7.2e-27)) {
		tmp = sin(x) * -eps;
	} else {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((x <= (-4.6d-52)) .or. (.not. (x <= 7.2d-27))) then
        tmp = sin(x) * -eps
    else
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((x <= -4.6e-52) || !(x <= 7.2e-27)) {
		tmp = Math.sin(x) * -eps;
	} else {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (x <= -4.6e-52) or not (x <= 7.2e-27):
		tmp = math.sin(x) * -eps
	else:
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((x <= -4.6e-52) || !(x <= 7.2e-27))
		tmp = Float64(sin(x) * Float64(-eps));
	else
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((x <= -4.6e-52) || ~((x <= 7.2e-27)))
		tmp = sin(x) * -eps;
	else
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[x, -4.6e-52], N[Not[LessEqual[x, 7.2e-27]], $MachinePrecision]], N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -4.6 \cdot 10^{-52} \lor \neg \left(x \leq 7.2 \cdot 10^{-27}\right):\\
\;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -4.59999999999999989e-52 or 7.1999999999999997e-27 < x

    1. Initial program 12.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 47.9%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*47.9%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg47.9%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified47.9%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]

    if -4.59999999999999989e-52 < x < 7.1999999999999997e-27

    1. Initial program 65.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos94.3%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv94.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval94.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr94.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. *-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \left(\left(x + \varepsilon\right) - x\right)\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      2. +-commutative94.3%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      3. associate--l+99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      4. +-inverses99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. distribute-lft-in99.6%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. metadata-eval99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + \color{blue}{0}\right) \cdot \sin \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. +-commutative99.6%

        \[\leadsto -2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \color{blue}{\left(\varepsilon + x\right)}\right)\right)\right) \]
    5. Simplified99.6%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \sin \left(0.5 \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\right)} \]
    6. Taylor expanded in x around 0 92.4%

      \[\leadsto -2 \cdot \color{blue}{{\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification65.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -4.6 \cdot 10^{-52} \lor \neg \left(x \leq 7.2 \cdot 10^{-27}\right):\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \end{array} \]

Alternative 13: 65.5% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := -1 + \cos \varepsilon\\ t_1 := \sin x \cdot \left(-\varepsilon\right)\\ \mathbf{if}\;\varepsilon \leq -0.00285:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\varepsilon \leq 5.2 \cdot 10^{-111}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-36}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\ \mathbf{elif}\;\varepsilon \leq 4.8 \cdot 10^{-6}:\\ \;\;\;\;t_1\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ -1.0 (cos eps))) (t_1 (* (sin x) (- eps))))
   (if (<= eps -0.00285)
     t_0
     (if (<= eps 5.2e-111)
       t_1
       (if (<= eps 5.5e-36)
         (* -0.5 (* eps eps))
         (if (<= eps 4.8e-6) t_1 t_0))))))
double code(double x, double eps) {
	double t_0 = -1.0 + cos(eps);
	double t_1 = sin(x) * -eps;
	double tmp;
	if (eps <= -0.00285) {
		tmp = t_0;
	} else if (eps <= 5.2e-111) {
		tmp = t_1;
	} else if (eps <= 5.5e-36) {
		tmp = -0.5 * (eps * eps);
	} else if (eps <= 4.8e-6) {
		tmp = t_1;
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = (-1.0d0) + cos(eps)
    t_1 = sin(x) * -eps
    if (eps <= (-0.00285d0)) then
        tmp = t_0
    else if (eps <= 5.2d-111) then
        tmp = t_1
    else if (eps <= 5.5d-36) then
        tmp = (-0.5d0) * (eps * eps)
    else if (eps <= 4.8d-6) then
        tmp = t_1
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = -1.0 + Math.cos(eps);
	double t_1 = Math.sin(x) * -eps;
	double tmp;
	if (eps <= -0.00285) {
		tmp = t_0;
	} else if (eps <= 5.2e-111) {
		tmp = t_1;
	} else if (eps <= 5.5e-36) {
		tmp = -0.5 * (eps * eps);
	} else if (eps <= 4.8e-6) {
		tmp = t_1;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, eps):
	t_0 = -1.0 + math.cos(eps)
	t_1 = math.sin(x) * -eps
	tmp = 0
	if eps <= -0.00285:
		tmp = t_0
	elif eps <= 5.2e-111:
		tmp = t_1
	elif eps <= 5.5e-36:
		tmp = -0.5 * (eps * eps)
	elif eps <= 4.8e-6:
		tmp = t_1
	else:
		tmp = t_0
	return tmp
function code(x, eps)
	t_0 = Float64(-1.0 + cos(eps))
	t_1 = Float64(sin(x) * Float64(-eps))
	tmp = 0.0
	if (eps <= -0.00285)
		tmp = t_0;
	elseif (eps <= 5.2e-111)
		tmp = t_1;
	elseif (eps <= 5.5e-36)
		tmp = Float64(-0.5 * Float64(eps * eps));
	elseif (eps <= 4.8e-6)
		tmp = t_1;
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = -1.0 + cos(eps);
	t_1 = sin(x) * -eps;
	tmp = 0.0;
	if (eps <= -0.00285)
		tmp = t_0;
	elseif (eps <= 5.2e-111)
		tmp = t_1;
	elseif (eps <= 5.5e-36)
		tmp = -0.5 * (eps * eps);
	elseif (eps <= 4.8e-6)
		tmp = t_1;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[Sin[x], $MachinePrecision] * (-eps)), $MachinePrecision]}, If[LessEqual[eps, -0.00285], t$95$0, If[LessEqual[eps, 5.2e-111], t$95$1, If[LessEqual[eps, 5.5e-36], N[(-0.5 * N[(eps * eps), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 4.8e-6], t$95$1, t$95$0]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := -1 + \cos \varepsilon\\
t_1 := \sin x \cdot \left(-\varepsilon\right)\\
\mathbf{if}\;\varepsilon \leq -0.00285:\\
\;\;\;\;t_0\\

\mathbf{elif}\;\varepsilon \leq 5.2 \cdot 10^{-111}:\\
\;\;\;\;t_1\\

\mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-36}:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\

\mathbf{elif}\;\varepsilon \leq 4.8 \cdot 10^{-6}:\\
\;\;\;\;t_1\\

\mathbf{else}:\\
\;\;\;\;t_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0028500000000000001 or 4.7999999999999998e-6 < eps

    1. Initial program 46.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 46.4%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -0.0028500000000000001 < eps < 5.19999999999999965e-111 or 5.49999999999999984e-36 < eps < 4.7999999999999998e-6

    1. Initial program 22.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 81.4%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*81.4%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg81.4%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified81.4%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]

    if 5.19999999999999965e-111 < eps < 5.49999999999999984e-36

    1. Initial program 4.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 4.4%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 66.8%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. unpow266.8%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
    5. Simplified66.8%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification63.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.00285:\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 5.2 \cdot 10^{-111}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-36}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\ \mathbf{elif}\;\varepsilon \leq 4.8 \cdot 10^{-6}:\\ \;\;\;\;\sin x \cdot \left(-\varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + \cos \varepsilon\\ \end{array} \]

Alternative 14: 46.7% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.00285 \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-13}\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.00285) (not (<= eps 4.3e-13)))
   (+ -1.0 (cos eps))
   (* -0.5 (* eps eps))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.00285) || !(eps <= 4.3e-13)) {
		tmp = -1.0 + cos(eps);
	} else {
		tmp = -0.5 * (eps * eps);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.00285d0)) .or. (.not. (eps <= 4.3d-13))) then
        tmp = (-1.0d0) + cos(eps)
    else
        tmp = (-0.5d0) * (eps * eps)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.00285) || !(eps <= 4.3e-13)) {
		tmp = -1.0 + Math.cos(eps);
	} else {
		tmp = -0.5 * (eps * eps);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.00285) or not (eps <= 4.3e-13):
		tmp = -1.0 + math.cos(eps)
	else:
		tmp = -0.5 * (eps * eps)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.00285) || !(eps <= 4.3e-13))
		tmp = Float64(-1.0 + cos(eps));
	else
		tmp = Float64(-0.5 * Float64(eps * eps));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.00285) || ~((eps <= 4.3e-13)))
		tmp = -1.0 + cos(eps);
	else
		tmp = -0.5 * (eps * eps);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.00285], N[Not[LessEqual[eps, 4.3e-13]], $MachinePrecision]], N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision], N[(-0.5 * N[(eps * eps), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.00285 \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-13}\right):\\
\;\;\;\;-1 + \cos \varepsilon\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0028500000000000001 or 4.2999999999999999e-13 < eps

    1. Initial program 45.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 45.5%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -0.0028500000000000001 < eps < 4.2999999999999999e-13

    1. Initial program 20.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 20.3%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 42.2%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. unpow242.2%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
    5. Simplified42.2%

      \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification43.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.00285 \lor \neg \left(\varepsilon \leq 4.3 \cdot 10^{-13}\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)\\ \end{array} \]

Alternative 15: 22.4% accurate, 41.0× speedup?

\[\begin{array}{l} \\ -0.5 \cdot \left(\varepsilon \cdot \varepsilon\right) \end{array} \]
(FPCore (x eps) :precision binary64 (* -0.5 (* eps eps)))
double code(double x, double eps) {
	return -0.5 * (eps * eps);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-0.5d0) * (eps * eps)
end function
public static double code(double x, double eps) {
	return -0.5 * (eps * eps);
}
def code(x, eps):
	return -0.5 * (eps * eps)
function code(x, eps)
	return Float64(-0.5 * Float64(eps * eps))
end
function tmp = code(x, eps)
	tmp = -0.5 * (eps * eps);
end
code[x_, eps_] := N[(-0.5 * N[(eps * eps), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)
\end{array}
Derivation
  1. Initial program 33.0%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 33.1%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Taylor expanded in eps around 0 22.4%

    \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  4. Step-by-step derivation
    1. unpow222.4%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  5. Simplified22.4%

    \[\leadsto \color{blue}{-0.5 \cdot \left(\varepsilon \cdot \varepsilon\right)} \]
  6. Final simplification22.4%

    \[\leadsto -0.5 \cdot \left(\varepsilon \cdot \varepsilon\right) \]

Reproduce

?
herbie shell --seed 2023173 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))