2cos (problem 3.3.5)

Percentage Accurate: 38.6% → 98.8%
Time: 17.4s
Alternatives: 13
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 13 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: 38.6% 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: 98.8% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.00019:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, -\mathsf{fma}\left(\sin x, \sin \varepsilon, \cos x\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -7.8)
   (- (fma (cos x) (cos eps) (* (- (sin x)) (sin eps))) (cos x))
   (if (<= eps 0.00019)
     (* (sin (/ (+ eps (- x x)) 2.0)) (* (sin (/ (+ eps (+ x x)) 2.0)) -2.0))
     (fma (cos x) (cos eps) (- (fma (sin x) (sin eps) (cos x)))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -7.8) {
		tmp = fma(cos(x), cos(eps), (-sin(x) * sin(eps))) - cos(x);
	} else if (eps <= 0.00019) {
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	} else {
		tmp = fma(cos(x), cos(eps), -fma(sin(x), sin(eps), cos(x)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -7.8)
		tmp = Float64(fma(cos(x), cos(eps), Float64(Float64(-sin(x)) * sin(eps))) - cos(x));
	elseif (eps <= 0.00019)
		tmp = Float64(sin(Float64(Float64(eps + Float64(x - x)) / 2.0)) * Float64(sin(Float64(Float64(eps + Float64(x + x)) / 2.0)) * -2.0));
	else
		tmp = fma(cos(x), cos(eps), Float64(-fma(sin(x), sin(eps), cos(x))));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -7.8], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[((-N[Sin[x], $MachinePrecision]) * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.00019], N[(N[Sin[N[(N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * N[(N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision], N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + (-N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision] + N[Cos[x], $MachinePrecision]), $MachinePrecision])), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -7.8:\\
\;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.00019:\\
\;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -7.79999999999999982

    1. Initial program 54.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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%

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

    if -7.79999999999999982 < eps < 1.9000000000000001e-4

    1. Initial program 35.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-exp-log34.0%

        \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    3. Applied egg-rr34.0%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    4. Step-by-step derivation
      1. add-exp-log35.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
      2. diff-cos52.1%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. Applied egg-rr52.1%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. *-commutative52.1%

        \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
      2. associate-*l*52.2%

        \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
      3. +-commutative52.2%

        \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      4. associate--l+99.7%

        \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      5. +-commutative99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
      6. associate-+l+99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
    7. Simplified99.7%

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

    if 1.9000000000000001e-4 < eps

    1. Initial program 48.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. associate--l-98.7%

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.00019:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, -\mathsf{fma}\left(\sin x, \sin \varepsilon, \cos x\right)\right)\\ \end{array} \]

Alternative 2: 98.8% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos x \cdot \cos \varepsilon\\ \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\left(t_0 - \sin x \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0054:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;t_0 - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (* (cos x) (cos eps))))
   (if (<= eps -7.8)
     (- (- t_0 (* (sin x) (sin eps))) (cos x))
     (if (<= eps 0.0054)
       (* (sin (/ (+ eps (- x x)) 2.0)) (* (sin (/ (+ eps (+ x x)) 2.0)) -2.0))
       (- t_0 (fma (sin eps) (sin x) (cos x)))))))
double code(double x, double eps) {
	double t_0 = cos(x) * cos(eps);
	double tmp;
	if (eps <= -7.8) {
		tmp = (t_0 - (sin(x) * sin(eps))) - cos(x);
	} else if (eps <= 0.0054) {
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	} else {
		tmp = t_0 - fma(sin(eps), sin(x), cos(x));
	}
	return tmp;
}
function code(x, eps)
	t_0 = Float64(cos(x) * cos(eps))
	tmp = 0.0
	if (eps <= -7.8)
		tmp = Float64(Float64(t_0 - Float64(sin(x) * sin(eps))) - cos(x));
	elseif (eps <= 0.0054)
		tmp = Float64(sin(Float64(Float64(eps + Float64(x - x)) / 2.0)) * Float64(sin(Float64(Float64(eps + Float64(x + x)) / 2.0)) * -2.0));
	else
		tmp = Float64(t_0 - fma(sin(eps), sin(x), cos(x)));
	end
	return tmp
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -7.8], N[(N[(t$95$0 - N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.0054], N[(N[Sin[N[(N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * N[(N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision], N[(t$95$0 - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos x \cdot \cos \varepsilon\\
\mathbf{if}\;\varepsilon \leq -7.8:\\
\;\;\;\;\left(t_0 - \sin x \cdot \sin \varepsilon\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.0054:\\
\;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\

\mathbf{else}:\\
\;\;\;\;t_0 - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -7.79999999999999982

    1. Initial program 54.3%

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

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

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

    if -7.79999999999999982 < eps < 0.0054000000000000003

    1. Initial program 35.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-exp-log34.0%

        \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    3. Applied egg-rr34.0%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    4. Step-by-step derivation
      1. add-exp-log35.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
      2. diff-cos52.1%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. Applied egg-rr52.1%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. *-commutative52.1%

        \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
      2. associate-*l*52.2%

        \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
      3. +-commutative52.2%

        \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      4. associate--l+99.7%

        \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      5. +-commutative99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
      6. associate-+l+99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
    7. Simplified99.7%

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

    if 0.0054000000000000003 < eps

    1. Initial program 48.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg48.0%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.7%

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

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.7%

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

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.7%

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0054:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \]

Alternative 3: 98.8% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0054:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -7.8)
   (- (fma (cos x) (cos eps) (* (- (sin x)) (sin eps))) (cos x))
   (if (<= eps 0.0054)
     (* (sin (/ (+ eps (- x x)) 2.0)) (* (sin (/ (+ eps (+ x x)) 2.0)) -2.0))
     (- (* (cos x) (cos eps)) (fma (sin eps) (sin x) (cos x))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -7.8) {
		tmp = fma(cos(x), cos(eps), (-sin(x) * sin(eps))) - cos(x);
	} else if (eps <= 0.0054) {
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	} else {
		tmp = (cos(x) * cos(eps)) - fma(sin(eps), sin(x), cos(x));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -7.8)
		tmp = Float64(fma(cos(x), cos(eps), Float64(Float64(-sin(x)) * sin(eps))) - cos(x));
	elseif (eps <= 0.0054)
		tmp = Float64(sin(Float64(Float64(eps + Float64(x - x)) / 2.0)) * Float64(sin(Float64(Float64(eps + Float64(x + x)) / 2.0)) * -2.0));
	else
		tmp = Float64(Float64(cos(x) * cos(eps)) - fma(sin(eps), sin(x), cos(x)));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -7.8], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[((-N[Sin[x], $MachinePrecision]) * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.0054], N[(N[Sin[N[(N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * N[(N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -7.8:\\
\;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.0054:\\
\;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -7.79999999999999982

    1. Initial program 54.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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%

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

    if -7.79999999999999982 < eps < 0.0054000000000000003

    1. Initial program 35.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-exp-log34.0%

        \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    3. Applied egg-rr34.0%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    4. Step-by-step derivation
      1. add-exp-log35.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
      2. diff-cos52.1%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. Applied egg-rr52.1%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. *-commutative52.1%

        \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
      2. associate-*l*52.2%

        \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
      3. +-commutative52.2%

        \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      4. associate--l+99.7%

        \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      5. +-commutative99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
      6. associate-+l+99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
    7. Simplified99.7%

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

    if 0.0054000000000000003 < eps

    1. Initial program 48.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg48.0%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.7%

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

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.7%

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

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.7%

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.0054:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\\ \end{array} \]

Alternative 4: 98.8% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8 \lor \neg \left(\varepsilon \leq 0.00096\right):\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin x \cdot \sin \varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -7.8) (not (<= eps 0.00096)))
   (- (* (cos x) (cos eps)) (+ (cos x) (* (sin x) (sin eps))))
   (* (sin (/ (+ eps (- x x)) 2.0)) (* (sin (/ (+ eps (+ x x)) 2.0)) -2.0))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -7.8) || !(eps <= 0.00096)) {
		tmp = (cos(x) * cos(eps)) - (cos(x) + (sin(x) * sin(eps)));
	} else {
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-7.8d0)) .or. (.not. (eps <= 0.00096d0))) then
        tmp = (cos(x) * cos(eps)) - (cos(x) + (sin(x) * sin(eps)))
    else
        tmp = sin(((eps + (x - x)) / 2.0d0)) * (sin(((eps + (x + x)) / 2.0d0)) * (-2.0d0))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -7.8) || !(eps <= 0.00096)) {
		tmp = (Math.cos(x) * Math.cos(eps)) - (Math.cos(x) + (Math.sin(x) * Math.sin(eps)));
	} else {
		tmp = Math.sin(((eps + (x - x)) / 2.0)) * (Math.sin(((eps + (x + x)) / 2.0)) * -2.0);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -7.8) or not (eps <= 0.00096):
		tmp = (math.cos(x) * math.cos(eps)) - (math.cos(x) + (math.sin(x) * math.sin(eps)))
	else:
		tmp = math.sin(((eps + (x - x)) / 2.0)) * (math.sin(((eps + (x + x)) / 2.0)) * -2.0)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -7.8) || !(eps <= 0.00096))
		tmp = Float64(Float64(cos(x) * cos(eps)) - Float64(cos(x) + Float64(sin(x) * sin(eps))));
	else
		tmp = Float64(sin(Float64(Float64(eps + Float64(x - x)) / 2.0)) * Float64(sin(Float64(Float64(eps + Float64(x + x)) / 2.0)) * -2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -7.8) || ~((eps <= 0.00096)))
		tmp = (cos(x) * cos(eps)) - (cos(x) + (sin(x) * sin(eps)));
	else
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -7.8], N[Not[LessEqual[eps, 0.00096]], $MachinePrecision]], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[(N[Cos[x], $MachinePrecision] + N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Sin[N[(N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * N[(N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -7.8 \lor \neg \left(\varepsilon \leq 0.00096\right):\\
\;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin x \cdot \sin \varepsilon\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -7.79999999999999982 or 9.60000000000000024e-4 < eps

    1. Initial program 51.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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%

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

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

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x + \left(-\sin \varepsilon \cdot \sin x\right)\right)} - \cos x \]
      3. sub-neg98.7%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)} - \cos x \]
      4. associate--l-98.6%

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

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

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

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

    if -7.79999999999999982 < eps < 9.60000000000000024e-4

    1. Initial program 35.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-exp-log34.0%

        \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    3. Applied egg-rr34.0%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    4. Step-by-step derivation
      1. add-exp-log35.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
      2. diff-cos52.1%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. Applied egg-rr52.1%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. *-commutative52.1%

        \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
      2. associate-*l*52.2%

        \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
      3. +-commutative52.2%

        \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      4. associate--l+99.7%

        \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      5. +-commutative99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
      6. associate-+l+99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
    7. Simplified99.7%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8 \lor \neg \left(\varepsilon \leq 0.00096\right):\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin x \cdot \sin \varepsilon\right)\\ \mathbf{else}:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \end{array} \]

Alternative 5: 98.8% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos x \cdot \cos \varepsilon\\ t_1 := \sin x \cdot \sin \varepsilon\\ \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\left(t_0 - t_1\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.00095:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;t_0 - \left(\cos x + t_1\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (* (cos x) (cos eps))) (t_1 (* (sin x) (sin eps))))
   (if (<= eps -7.8)
     (- (- t_0 t_1) (cos x))
     (if (<= eps 0.00095)
       (* (sin (/ (+ eps (- x x)) 2.0)) (* (sin (/ (+ eps (+ x x)) 2.0)) -2.0))
       (- t_0 (+ (cos x) t_1))))))
double code(double x, double eps) {
	double t_0 = cos(x) * cos(eps);
	double t_1 = sin(x) * sin(eps);
	double tmp;
	if (eps <= -7.8) {
		tmp = (t_0 - t_1) - cos(x);
	} else if (eps <= 0.00095) {
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	} else {
		tmp = t_0 - (cos(x) + t_1);
	}
	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 = cos(x) * cos(eps)
    t_1 = sin(x) * sin(eps)
    if (eps <= (-7.8d0)) then
        tmp = (t_0 - t_1) - cos(x)
    else if (eps <= 0.00095d0) then
        tmp = sin(((eps + (x - x)) / 2.0d0)) * (sin(((eps + (x + x)) / 2.0d0)) * (-2.0d0))
    else
        tmp = t_0 - (cos(x) + t_1)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.cos(x) * Math.cos(eps);
	double t_1 = Math.sin(x) * Math.sin(eps);
	double tmp;
	if (eps <= -7.8) {
		tmp = (t_0 - t_1) - Math.cos(x);
	} else if (eps <= 0.00095) {
		tmp = Math.sin(((eps + (x - x)) / 2.0)) * (Math.sin(((eps + (x + x)) / 2.0)) * -2.0);
	} else {
		tmp = t_0 - (Math.cos(x) + t_1);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos(x) * math.cos(eps)
	t_1 = math.sin(x) * math.sin(eps)
	tmp = 0
	if eps <= -7.8:
		tmp = (t_0 - t_1) - math.cos(x)
	elif eps <= 0.00095:
		tmp = math.sin(((eps + (x - x)) / 2.0)) * (math.sin(((eps + (x + x)) / 2.0)) * -2.0)
	else:
		tmp = t_0 - (math.cos(x) + t_1)
	return tmp
function code(x, eps)
	t_0 = Float64(cos(x) * cos(eps))
	t_1 = Float64(sin(x) * sin(eps))
	tmp = 0.0
	if (eps <= -7.8)
		tmp = Float64(Float64(t_0 - t_1) - cos(x));
	elseif (eps <= 0.00095)
		tmp = Float64(sin(Float64(Float64(eps + Float64(x - x)) / 2.0)) * Float64(sin(Float64(Float64(eps + Float64(x + x)) / 2.0)) * -2.0));
	else
		tmp = Float64(t_0 - Float64(cos(x) + t_1));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos(x) * cos(eps);
	t_1 = sin(x) * sin(eps);
	tmp = 0.0;
	if (eps <= -7.8)
		tmp = (t_0 - t_1) - cos(x);
	elseif (eps <= 0.00095)
		tmp = sin(((eps + (x - x)) / 2.0)) * (sin(((eps + (x + x)) / 2.0)) * -2.0);
	else
		tmp = t_0 - (cos(x) + t_1);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[Sin[x], $MachinePrecision] * N[Sin[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -7.8], N[(N[(t$95$0 - t$95$1), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.00095], N[(N[Sin[N[(N[(eps + N[(x - x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * N[(N[Sin[N[(N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision], N[(t$95$0 - N[(N[Cos[x], $MachinePrecision] + t$95$1), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos x \cdot \cos \varepsilon\\
t_1 := \sin x \cdot \sin \varepsilon\\
\mathbf{if}\;\varepsilon \leq -7.8:\\
\;\;\;\;\left(t_0 - t_1\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.00095:\\
\;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\

\mathbf{else}:\\
\;\;\;\;t_0 - \left(\cos x + t_1\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -7.79999999999999982

    1. Initial program 54.3%

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

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

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

    if -7.79999999999999982 < eps < 9.49999999999999998e-4

    1. Initial program 35.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-exp-log34.0%

        \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    3. Applied egg-rr34.0%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
    4. Step-by-step derivation
      1. add-exp-log35.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
      2. diff-cos52.1%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. Applied egg-rr52.1%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. *-commutative52.1%

        \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
      2. associate-*l*52.2%

        \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
      3. +-commutative52.2%

        \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      4. associate--l+99.7%

        \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
      5. +-commutative99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
      6. associate-+l+99.7%

        \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
    7. Simplified99.7%

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

    if 9.49999999999999998e-4 < eps

    1. Initial program 48.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.6%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.6%

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

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    4. Taylor expanded in x around inf 98.6%

      \[\leadsto \color{blue}{\left(-1 \cdot \left(\sin \varepsilon \cdot \sin x\right) + \cos \varepsilon \cdot \cos x\right) - \cos x} \]
    5. Step-by-step derivation
      1. neg-mul-198.6%

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

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x + \left(-\sin \varepsilon \cdot \sin x\right)\right)} - \cos x \]
      3. sub-neg98.6%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)} - \cos x \]
      4. associate--l-98.7%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\sin \varepsilon \cdot \sin x + \cos x\right)} \]
      5. *-commutative98.7%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon} - \left(\sin \varepsilon \cdot \sin x + \cos x\right) \]
      6. *-commutative98.7%

        \[\leadsto \cos x \cdot \cos \varepsilon - \left(\color{blue}{\sin x \cdot \sin \varepsilon} + \cos x\right) \]
    6. Simplified98.7%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7.8:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.00095:\\ \;\;\;\;\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin x \cdot \sin \varepsilon\right)\\ \end{array} \]

Alternative 6: 76.8% accurate, 0.9× speedup?

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

\\
\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)
\end{array}
Derivation
  1. Initial program 43.1%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-exp-log29.9%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
  3. Applied egg-rr29.9%

    \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
  4. Step-by-step derivation
    1. add-exp-log43.1%

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    2. diff-cos51.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
  5. Applied egg-rr51.5%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
  6. Step-by-step derivation
    1. *-commutative51.5%

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    2. associate-*l*51.5%

      \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
    3. +-commutative51.5%

      \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
    4. associate--l+76.6%

      \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
    5. +-commutative76.6%

      \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
    6. associate-+l+76.6%

      \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
  7. Simplified76.6%

    \[\leadsto \color{blue}{\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)} \]
  8. Final simplification76.6%

    \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right) \]

Alternative 7: 76.8% accurate, 1.0× speedup?

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

\\
-2 \cdot \left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - x \cdot -2\right)\right)\right)
\end{array}
Derivation
  1. Initial program 43.1%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-exp-log29.9%

      \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
  3. Applied egg-rr29.9%

    \[\leadsto \color{blue}{e^{\log \cos \left(x + \varepsilon\right)}} - \cos x \]
  4. Step-by-step derivation
    1. add-exp-log43.1%

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    2. diff-cos51.5%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
  5. Applied egg-rr51.5%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
  6. Step-by-step derivation
    1. *-commutative51.5%

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    2. associate-*l*51.5%

      \[\leadsto \color{blue}{\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right)} \]
    3. +-commutative51.5%

      \[\leadsto \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
    4. associate--l+76.6%

      \[\leadsto \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right) \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right) \cdot -2\right) \]
    5. +-commutative76.6%

      \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right) \cdot -2\right) \]
    6. associate-+l+76.6%

      \[\leadsto \sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \cdot -2\right) \]
  7. Simplified76.6%

    \[\leadsto \color{blue}{\sin \left(\frac{\varepsilon + \left(x - x\right)}{2}\right) \cdot \left(\sin \left(\frac{\varepsilon + \left(x + x\right)}{2}\right) \cdot -2\right)} \]
  8. Taylor expanded in x around -inf 76.6%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)} \]
  9. Final simplification76.6%

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

Alternative 8: 67.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \varepsilon - \cos x\\ t_1 := -0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{if}\;\varepsilon \leq -5 \cdot 10^{-5}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\varepsilon \leq -3.4 \cdot 10^{-71}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\varepsilon \leq 3.5 \cdot 10^{-79}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.7:\\ \;\;\;\;t_1\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (- (cos eps) (cos x))) (t_1 (* -0.5 (* eps (+ x (+ eps x))))))
   (if (<= eps -5e-5)
     t_0
     (if (<= eps -3.4e-71)
       t_1
       (if (<= eps 3.5e-79) (* eps (- (sin x))) (if (<= eps 4.7) t_1 t_0))))))
double code(double x, double eps) {
	double t_0 = cos(eps) - cos(x);
	double t_1 = -0.5 * (eps * (x + (eps + x)));
	double tmp;
	if (eps <= -5e-5) {
		tmp = t_0;
	} else if (eps <= -3.4e-71) {
		tmp = t_1;
	} else if (eps <= 3.5e-79) {
		tmp = eps * -sin(x);
	} else if (eps <= 4.7) {
		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 = cos(eps) - cos(x)
    t_1 = (-0.5d0) * (eps * (x + (eps + x)))
    if (eps <= (-5d-5)) then
        tmp = t_0
    else if (eps <= (-3.4d-71)) then
        tmp = t_1
    else if (eps <= 3.5d-79) then
        tmp = eps * -sin(x)
    else if (eps <= 4.7d0) 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 = Math.cos(eps) - Math.cos(x);
	double t_1 = -0.5 * (eps * (x + (eps + x)));
	double tmp;
	if (eps <= -5e-5) {
		tmp = t_0;
	} else if (eps <= -3.4e-71) {
		tmp = t_1;
	} else if (eps <= 3.5e-79) {
		tmp = eps * -Math.sin(x);
	} else if (eps <= 4.7) {
		tmp = t_1;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos(eps) - math.cos(x)
	t_1 = -0.5 * (eps * (x + (eps + x)))
	tmp = 0
	if eps <= -5e-5:
		tmp = t_0
	elif eps <= -3.4e-71:
		tmp = t_1
	elif eps <= 3.5e-79:
		tmp = eps * -math.sin(x)
	elif eps <= 4.7:
		tmp = t_1
	else:
		tmp = t_0
	return tmp
function code(x, eps)
	t_0 = Float64(cos(eps) - cos(x))
	t_1 = Float64(-0.5 * Float64(eps * Float64(x + Float64(eps + x))))
	tmp = 0.0
	if (eps <= -5e-5)
		tmp = t_0;
	elseif (eps <= -3.4e-71)
		tmp = t_1;
	elseif (eps <= 3.5e-79)
		tmp = Float64(eps * Float64(-sin(x)));
	elseif (eps <= 4.7)
		tmp = t_1;
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos(eps) - cos(x);
	t_1 = -0.5 * (eps * (x + (eps + x)));
	tmp = 0.0;
	if (eps <= -5e-5)
		tmp = t_0;
	elseif (eps <= -3.4e-71)
		tmp = t_1;
	elseif (eps <= 3.5e-79)
		tmp = eps * -sin(x);
	elseif (eps <= 4.7)
		tmp = t_1;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(-0.5 * N[(eps * N[(x + N[(eps + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -5e-5], t$95$0, If[LessEqual[eps, -3.4e-71], t$95$1, If[LessEqual[eps, 3.5e-79], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision], If[LessEqual[eps, 4.7], t$95$1, t$95$0]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \varepsilon - \cos x\\
t_1 := -0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\
\mathbf{if}\;\varepsilon \leq -5 \cdot 10^{-5}:\\
\;\;\;\;t_0\\

\mathbf{elif}\;\varepsilon \leq -3.4 \cdot 10^{-71}:\\
\;\;\;\;t_1\\

\mathbf{elif}\;\varepsilon \leq 3.5 \cdot 10^{-79}:\\
\;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\

\mathbf{elif}\;\varepsilon \leq 4.7:\\
\;\;\;\;t_1\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -5.00000000000000024e-5 or 4.70000000000000018 < eps

    1. Initial program 52.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 53.8%

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

    if -5.00000000000000024e-5 < eps < -3.40000000000000003e-71 or 3.5000000000000003e-79 < eps < 4.70000000000000018

    1. Initial program 7.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 7.6%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 65.3%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. +-rgt-identity65.3%

        \[\leadsto -0.5 \cdot {\color{blue}{\left(\varepsilon + 0\right)}}^{2} \]
      2. metadata-eval65.3%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(0 - 0\right)}\right)}^{2} \]
      3. +-inverses65.3%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\color{blue}{\left(x - x\right)} - 0\right)\right)}^{2} \]
      4. +-inverses65.3%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\left(x - x\right) - \color{blue}{\left(x - x\right)}\right)\right)}^{2} \]
      5. flip--0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\frac{\left(x - x\right) \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}}\right)}^{2} \]
      6. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      7. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 \cdot \color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      8. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      9. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0} \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      10. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - 0 \cdot \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      11. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      12. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      13. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{x \cdot x - x \cdot x}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      14. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0} + \left(x - x\right)}\right)}^{2} \]
      15. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{0 + \color{blue}{0}}\right)}^{2} \]
      16. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0}}\right)}^{2} \]
      17. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{x - x}}\right)}^{2} \]
      18. flip-+64.6%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(x + x\right)}\right)}^{2} \]
      19. pow264.6%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
      20. associate-+r+64.6%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{\left(\left(\varepsilon + x\right) + x\right)}\right) \]
      21. +-commutative64.6%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
      22. distribute-rgt-in64.6%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) \cdot \left(\varepsilon + \left(x + x\right)\right) + x \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
    5. Applied egg-rr72.5%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + x\right) \cdot \varepsilon + x \cdot \varepsilon\right)} \]
    6. Step-by-step derivation
      1. distribute-rgt-out72.5%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(\varepsilon + x\right) + x\right)\right)} \]
      2. +-commutative72.5%

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

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

    if -3.40000000000000003e-71 < eps < 3.5000000000000003e-79

    1. Initial program 42.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 97.1%

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

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative97.1%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in97.1%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified97.1%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification73.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -5 \cdot 10^{-5}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{elif}\;\varepsilon \leq -3.4 \cdot 10^{-71}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 3.5 \cdot 10^{-79}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.7:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \]

Alternative 9: 67.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-69} \lor \neg \left(\varepsilon \leq 8 \cdot 10^{-30}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -3e-69) (not (<= eps 8e-30)))
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))
   (* eps (- (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -3e-69) || !(eps <= 8e-30)) {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	} else {
		tmp = eps * -sin(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-3d-69)) .or. (.not. (eps <= 8d-30))) then
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    else
        tmp = eps * -sin(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -3e-69) || !(eps <= 8e-30)) {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	} else {
		tmp = eps * -Math.sin(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -3e-69) or not (eps <= 8e-30):
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	else:
		tmp = eps * -math.sin(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -3e-69) || !(eps <= 8e-30))
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	else
		tmp = Float64(eps * Float64(-sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -3e-69) || ~((eps <= 8e-30)))
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	else
		tmp = eps * -sin(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -3e-69], N[Not[LessEqual[eps, 8e-30]], $MachinePrecision]], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-69} \lor \neg \left(\varepsilon \leq 8 \cdot 10^{-30}\right):\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.99999999999999989e-69 or 8.000000000000001e-30 < eps

    1. Initial program 46.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos55.8%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv55.8%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+55.8%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval55.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv55.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative55.8%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+55.9%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval55.9%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr55.9%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*55.9%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative55.9%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative55.9%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative55.9%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-255.9%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def55.9%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg55.9%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg55.9%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative55.9%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub058.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified58.7%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in x around 0 55.7%

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

    if -2.99999999999999989e-69 < eps < 8.000000000000001e-30

    1. Initial program 38.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 93.1%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg93.1%

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative93.1%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in93.1%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified93.1%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification71.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-69} \lor \neg \left(\varepsilon \leq 8 \cdot 10^{-30}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \end{array} \]

Alternative 10: 67.0% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \varepsilon + -1\\ t_1 := -0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{if}\;\varepsilon \leq -0.006:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\varepsilon \leq -3.2 \cdot 10^{-72}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\varepsilon \leq 1.6 \cdot 10^{-79}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.7:\\ \;\;\;\;t_1\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ (cos eps) -1.0)) (t_1 (* -0.5 (* eps (+ x (+ eps x))))))
   (if (<= eps -0.006)
     t_0
     (if (<= eps -3.2e-72)
       t_1
       (if (<= eps 1.6e-79) (* eps (- (sin x))) (if (<= eps 4.7) t_1 t_0))))))
double code(double x, double eps) {
	double t_0 = cos(eps) + -1.0;
	double t_1 = -0.5 * (eps * (x + (eps + x)));
	double tmp;
	if (eps <= -0.006) {
		tmp = t_0;
	} else if (eps <= -3.2e-72) {
		tmp = t_1;
	} else if (eps <= 1.6e-79) {
		tmp = eps * -sin(x);
	} else if (eps <= 4.7) {
		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 = cos(eps) + (-1.0d0)
    t_1 = (-0.5d0) * (eps * (x + (eps + x)))
    if (eps <= (-0.006d0)) then
        tmp = t_0
    else if (eps <= (-3.2d-72)) then
        tmp = t_1
    else if (eps <= 1.6d-79) then
        tmp = eps * -sin(x)
    else if (eps <= 4.7d0) 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 = Math.cos(eps) + -1.0;
	double t_1 = -0.5 * (eps * (x + (eps + x)));
	double tmp;
	if (eps <= -0.006) {
		tmp = t_0;
	} else if (eps <= -3.2e-72) {
		tmp = t_1;
	} else if (eps <= 1.6e-79) {
		tmp = eps * -Math.sin(x);
	} else if (eps <= 4.7) {
		tmp = t_1;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos(eps) + -1.0
	t_1 = -0.5 * (eps * (x + (eps + x)))
	tmp = 0
	if eps <= -0.006:
		tmp = t_0
	elif eps <= -3.2e-72:
		tmp = t_1
	elif eps <= 1.6e-79:
		tmp = eps * -math.sin(x)
	elif eps <= 4.7:
		tmp = t_1
	else:
		tmp = t_0
	return tmp
function code(x, eps)
	t_0 = Float64(cos(eps) + -1.0)
	t_1 = Float64(-0.5 * Float64(eps * Float64(x + Float64(eps + x))))
	tmp = 0.0
	if (eps <= -0.006)
		tmp = t_0;
	elseif (eps <= -3.2e-72)
		tmp = t_1;
	elseif (eps <= 1.6e-79)
		tmp = Float64(eps * Float64(-sin(x)));
	elseif (eps <= 4.7)
		tmp = t_1;
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos(eps) + -1.0;
	t_1 = -0.5 * (eps * (x + (eps + x)));
	tmp = 0.0;
	if (eps <= -0.006)
		tmp = t_0;
	elseif (eps <= -3.2e-72)
		tmp = t_1;
	elseif (eps <= 1.6e-79)
		tmp = eps * -sin(x);
	elseif (eps <= 4.7)
		tmp = t_1;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision]}, Block[{t$95$1 = N[(-0.5 * N[(eps * N[(x + N[(eps + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -0.006], t$95$0, If[LessEqual[eps, -3.2e-72], t$95$1, If[LessEqual[eps, 1.6e-79], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision], If[LessEqual[eps, 4.7], t$95$1, t$95$0]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \varepsilon + -1\\
t_1 := -0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\
\mathbf{if}\;\varepsilon \leq -0.006:\\
\;\;\;\;t_0\\

\mathbf{elif}\;\varepsilon \leq -3.2 \cdot 10^{-72}:\\
\;\;\;\;t_1\\

\mathbf{elif}\;\varepsilon \leq 1.6 \cdot 10^{-79}:\\
\;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\

\mathbf{elif}\;\varepsilon \leq 4.7:\\
\;\;\;\;t_1\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0060000000000000001 or 4.70000000000000018 < eps

    1. Initial program 52.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 52.6%

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

    if -0.0060000000000000001 < eps < -3.19999999999999999e-72 or 1.59999999999999994e-79 < eps < 4.70000000000000018

    1. Initial program 9.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 7.4%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 63.2%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. +-rgt-identity63.2%

        \[\leadsto -0.5 \cdot {\color{blue}{\left(\varepsilon + 0\right)}}^{2} \]
      2. metadata-eval63.2%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(0 - 0\right)}\right)}^{2} \]
      3. +-inverses63.2%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\color{blue}{\left(x - x\right)} - 0\right)\right)}^{2} \]
      4. +-inverses63.2%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\left(x - x\right) - \color{blue}{\left(x - x\right)}\right)\right)}^{2} \]
      5. flip--0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\frac{\left(x - x\right) \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}}\right)}^{2} \]
      6. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      7. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 \cdot \color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      8. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      9. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0} \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      10. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - 0 \cdot \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      11. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      12. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      13. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{x \cdot x - x \cdot x}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      14. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0} + \left(x - x\right)}\right)}^{2} \]
      15. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{0 + \color{blue}{0}}\right)}^{2} \]
      16. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0}}\right)}^{2} \]
      17. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{x - x}}\right)}^{2} \]
      18. flip-+62.6%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(x + x\right)}\right)}^{2} \]
      19. pow262.6%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
      20. associate-+r+62.6%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{\left(\left(\varepsilon + x\right) + x\right)}\right) \]
      21. +-commutative62.6%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
      22. distribute-rgt-in62.6%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) \cdot \left(\varepsilon + \left(x + x\right)\right) + x \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
    5. Applied egg-rr70.6%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + x\right) \cdot \varepsilon + x \cdot \varepsilon\right)} \]
    6. Step-by-step derivation
      1. distribute-rgt-out70.6%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(\varepsilon + x\right) + x\right)\right)} \]
      2. +-commutative70.6%

        \[\leadsto -0.5 \cdot \left(\varepsilon \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
    7. Simplified70.6%

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

    if -3.19999999999999999e-72 < eps < 1.59999999999999994e-79

    1. Initial program 42.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 97.1%

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

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative97.1%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in97.1%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified97.1%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification72.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.006:\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{elif}\;\varepsilon \leq -3.2 \cdot 10^{-72}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 1.6 \cdot 10^{-79}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.7:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon + -1\\ \end{array} \]

Alternative 11: 52.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.006 \lor \neg \left(\varepsilon \leq 4.7\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.006) (not (<= eps 4.7)))
   (+ (cos eps) -1.0)
   (* -0.5 (* eps (+ x (+ eps x))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.006) || !(eps <= 4.7)) {
		tmp = cos(eps) + -1.0;
	} else {
		tmp = -0.5 * (eps * (x + (eps + x)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.006d0)) .or. (.not. (eps <= 4.7d0))) then
        tmp = cos(eps) + (-1.0d0)
    else
        tmp = (-0.5d0) * (eps * (x + (eps + x)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.006) || !(eps <= 4.7)) {
		tmp = Math.cos(eps) + -1.0;
	} else {
		tmp = -0.5 * (eps * (x + (eps + x)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.006) or not (eps <= 4.7):
		tmp = math.cos(eps) + -1.0
	else:
		tmp = -0.5 * (eps * (x + (eps + x)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.006) || !(eps <= 4.7))
		tmp = Float64(cos(eps) + -1.0);
	else
		tmp = Float64(-0.5 * Float64(eps * Float64(x + Float64(eps + x))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.006) || ~((eps <= 4.7)))
		tmp = cos(eps) + -1.0;
	else
		tmp = -0.5 * (eps * (x + (eps + x)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.006], N[Not[LessEqual[eps, 4.7]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], N[(-0.5 * N[(eps * N[(x + N[(eps + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.006 \lor \neg \left(\varepsilon \leq 4.7\right):\\
\;\;\;\;\cos \varepsilon + -1\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0060000000000000001 or 4.70000000000000018 < eps

    1. Initial program 52.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 52.6%

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

    if -0.0060000000000000001 < eps < 4.70000000000000018

    1. Initial program 34.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 34.0%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 49.0%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. +-rgt-identity49.0%

        \[\leadsto -0.5 \cdot {\color{blue}{\left(\varepsilon + 0\right)}}^{2} \]
      2. metadata-eval49.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(0 - 0\right)}\right)}^{2} \]
      3. +-inverses49.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\color{blue}{\left(x - x\right)} - 0\right)\right)}^{2} \]
      4. +-inverses49.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\left(x - x\right) - \color{blue}{\left(x - x\right)}\right)\right)}^{2} \]
      5. flip--0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\frac{\left(x - x\right) \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}}\right)}^{2} \]
      6. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      7. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 \cdot \color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      8. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      9. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0} \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      10. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - 0 \cdot \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      11. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      12. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      13. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{x \cdot x - x \cdot x}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
      14. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0} + \left(x - x\right)}\right)}^{2} \]
      15. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{0 + \color{blue}{0}}\right)}^{2} \]
      16. metadata-eval0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0}}\right)}^{2} \]
      17. +-inverses0.0%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{x - x}}\right)}^{2} \]
      18. flip-+35.3%

        \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(x + x\right)}\right)}^{2} \]
      19. pow235.3%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
      20. associate-+r+35.3%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{\left(\left(\varepsilon + x\right) + x\right)}\right) \]
      21. +-commutative35.3%

        \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
      22. distribute-rgt-in35.3%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) \cdot \left(\varepsilon + \left(x + x\right)\right) + x \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
    5. Applied egg-rr61.9%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + x\right) \cdot \varepsilon + x \cdot \varepsilon\right)} \]
    6. Step-by-step derivation
      1. distribute-rgt-out61.9%

        \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(\varepsilon + x\right) + x\right)\right)} \]
      2. +-commutative61.9%

        \[\leadsto -0.5 \cdot \left(\varepsilon \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
    7. Simplified61.9%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(x + \varepsilon\right) + x\right)\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification57.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.006 \lor \neg \left(\varepsilon \leq 4.7\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)\\ \end{array} \]

Alternative 12: 27.5% accurate, 22.8× speedup?

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

\\
-0.5 \cdot \left(\varepsilon \cdot \left(x + \left(\varepsilon + x\right)\right)\right)
\end{array}
Derivation
  1. Initial program 43.1%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 43.0%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Taylor expanded in eps around 0 27.0%

    \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  4. Step-by-step derivation
    1. +-rgt-identity27.0%

      \[\leadsto -0.5 \cdot {\color{blue}{\left(\varepsilon + 0\right)}}^{2} \]
    2. metadata-eval27.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(0 - 0\right)}\right)}^{2} \]
    3. +-inverses27.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\color{blue}{\left(x - x\right)} - 0\right)\right)}^{2} \]
    4. +-inverses27.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \left(\left(x - x\right) - \color{blue}{\left(x - x\right)}\right)\right)}^{2} \]
    5. flip--0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\frac{\left(x - x\right) \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}}\right)}^{2} \]
    6. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} \cdot \left(x - x\right) - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    7. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 \cdot \color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    8. metadata-eval0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0} - \left(x - x\right) \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    9. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0} \cdot \left(x - x\right)}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    10. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - 0 \cdot \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    11. metadata-eval0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{0 - \color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    12. metadata-eval0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{0}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    13. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{\color{blue}{x \cdot x - x \cdot x}}{\left(x - x\right) + \left(x - x\right)}\right)}^{2} \]
    14. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0} + \left(x - x\right)}\right)}^{2} \]
    15. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{0 + \color{blue}{0}}\right)}^{2} \]
    16. metadata-eval0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{0}}\right)}^{2} \]
    17. +-inverses0.0%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \frac{x \cdot x - x \cdot x}{\color{blue}{x - x}}\right)}^{2} \]
    18. flip-+19.8%

      \[\leadsto -0.5 \cdot {\left(\varepsilon + \color{blue}{\left(x + x\right)}\right)}^{2} \]
    19. pow219.8%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
    20. associate-+r+19.8%

      \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{\left(\left(\varepsilon + x\right) + x\right)}\right) \]
    21. +-commutative19.8%

      \[\leadsto -0.5 \cdot \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
    22. distribute-rgt-in19.8%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) \cdot \left(\varepsilon + \left(x + x\right)\right) + x \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \]
  5. Applied egg-rr33.5%

    \[\leadsto -0.5 \cdot \color{blue}{\left(\left(\varepsilon + x\right) \cdot \varepsilon + x \cdot \varepsilon\right)} \]
  6. Step-by-step derivation
    1. distribute-rgt-out33.6%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(\varepsilon + x\right) + x\right)\right)} \]
    2. +-commutative33.6%

      \[\leadsto -0.5 \cdot \left(\varepsilon \cdot \left(\color{blue}{\left(x + \varepsilon\right)} + x\right)\right) \]
  7. Simplified33.6%

    \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \left(\left(x + \varepsilon\right) + x\right)\right)} \]
  8. Final simplification33.6%

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

Alternative 13: 21.9% 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 43.1%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 43.0%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Taylor expanded in eps around 0 27.0%

    \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  4. Step-by-step derivation
    1. unpow227.0%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  5. Applied egg-rr27.0%

    \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  6. Final simplification27.0%

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

Reproduce

?
herbie shell --seed 2023333 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))