2cos (problem 3.3.5)

Percentage Accurate: 53.7% → 99.3%
Time: 14.6s
Alternatives: 16
Speedup: 29.3×

Specification

?
\[\left(\left(-10000 \leq x \land x \leq 10000\right) \land 10^{-16} \cdot \left|x\right| < \varepsilon\right) \land \varepsilon < \left|x\right|\]
\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(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 16 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: 53.7% accurate, 1.0× speedup?

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

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

Alternative 1: 99.3% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* (* -2.0 (sin (* 0.5 (fma 2.0 x eps)))) (sin (* 0.5 eps))))
double code(double x, double eps) {
	return (-2.0 * sin((0.5 * fma(2.0, x, eps)))) * sin((0.5 * eps));
}
function code(x, eps)
	return Float64(Float64(-2.0 * sin(Float64(0.5 * fma(2.0, x, eps)))) * sin(Float64(0.5 * eps)))
end
code[x_, eps_] := N[(N[(-2.0 * N[Sin[N[(0.5 * N[(2.0 * x + eps), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sin[N[(0.5 * eps), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. diff-cos84.9%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv84.9%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. associate--l+84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. metadata-eval84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    5. div-inv84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    6. +-commutative84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
    7. associate-+l+84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    8. metadata-eval84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  4. Applied egg-rr84.9%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
  5. Step-by-step derivation
    1. associate-*r*84.9%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
    2. *-commutative84.9%

      \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot -2\right)} \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \]
    3. associate-*l*84.9%

      \[\leadsto \color{blue}{\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. *-commutative84.9%

      \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon - x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    5. associate-+r-84.9%

      \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    6. +-commutative84.9%

      \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    7. associate--l+99.2%

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

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

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

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

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

      \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
    13. count-299.2%

      \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right)\right) \]
    14. fma-define99.2%

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

    \[\leadsto \color{blue}{\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right)} \]
  7. Final simplification99.2%

    \[\leadsto \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right) \]
  8. Add Preprocessing

Alternative 2: 98.8% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000148:\\ \;\;\;\;\left(0.5 \cdot \varepsilon\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.000148)
   (* (* 0.5 eps) (* -2.0 (sin (* 0.5 (fma 2.0 x eps)))))
   (- (cos (+ eps x)) (cos x))))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.000148) {
		tmp = (0.5 * eps) * (-2.0 * sin((0.5 * fma(2.0, x, eps))));
	} else {
		tmp = cos((eps + x)) - cos(x);
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.000148)
		tmp = Float64(Float64(0.5 * eps) * Float64(-2.0 * sin(Float64(0.5 * fma(2.0, x, eps)))));
	else
		tmp = Float64(cos(Float64(eps + x)) - cos(x));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, 0.000148], N[(N[(0.5 * eps), $MachinePrecision] * N[(-2.0 * N[Sin[N[(0.5 * N[(2.0 * x + eps), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.000148:\\
\;\;\;\;\left(0.5 \cdot \varepsilon\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 1.47999999999999992e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. diff-cos84.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    4. Applied egg-rr84.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    5. Step-by-step derivation
      1. associate-*r*84.7%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative84.7%

        \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot -2\right)} \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \]
      3. associate-*l*84.7%

        \[\leadsto \color{blue}{\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
      4. *-commutative84.7%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon - x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      5. associate-+r-84.7%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      6. +-commutative84.7%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      7. associate--l+99.8%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      8. +-inverses99.8%

        \[\leadsto \sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      9. distribute-lft-in99.8%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      10. metadata-eval99.8%

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

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

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      13. count-299.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right)\right) \]
      14. fma-define99.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right)\right) \]
    6. Simplified99.8%

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

      \[\leadsto \color{blue}{\left(0.5 \cdot \varepsilon\right)} \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \]
    8. Step-by-step derivation
      1. *-commutative99.7%

        \[\leadsto \color{blue}{\left(\varepsilon \cdot 0.5\right)} \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \]
    9. Simplified99.7%

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

    if 1.47999999999999992e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification98.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000148:\\ \;\;\;\;\left(0.5 \cdot \varepsilon\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) - \cos x\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.3% accurate, 1.0× speedup?

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

\\
-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. diff-cos84.9%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv84.9%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. associate--l+84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. metadata-eval84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    5. div-inv84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    6. +-commutative84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
    7. associate-+l+84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    8. metadata-eval84.9%

      \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  4. Applied egg-rr84.9%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
  5. Step-by-step derivation
    1. associate-*r*84.9%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
    2. *-commutative84.9%

      \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot -2\right)} \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \]
    3. associate-*l*84.9%

      \[\leadsto \color{blue}{\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. *-commutative84.9%

      \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon - x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    5. associate-+r-84.9%

      \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    6. +-commutative84.9%

      \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
    7. associate--l+99.2%

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

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

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

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

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

      \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
    13. count-299.2%

      \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right)\right) \]
    14. fma-define99.2%

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

    \[\leadsto \color{blue}{\sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right)} \]
  7. Taylor expanded in x around -inf 99.2%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)} \]
  8. Add Preprocessing

Alternative 4: 98.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00016:\\ \;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.00016)
   (* -2.0 (* (* 0.5 eps) (sin (* 0.5 (- eps (* -2.0 x))))))
   (- (cos (+ eps x)) (cos x))))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00016) {
		tmp = -2.0 * ((0.5 * eps) * sin((0.5 * (eps - (-2.0 * x)))));
	} else {
		tmp = cos((eps + x)) - cos(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.00016d0) then
        tmp = (-2.0d0) * ((0.5d0 * eps) * sin((0.5d0 * (eps - ((-2.0d0) * x)))))
    else
        tmp = cos((eps + x)) - cos(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00016) {
		tmp = -2.0 * ((0.5 * eps) * Math.sin((0.5 * (eps - (-2.0 * x)))));
	} else {
		tmp = Math.cos((eps + x)) - Math.cos(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.00016:
		tmp = -2.0 * ((0.5 * eps) * math.sin((0.5 * (eps - (-2.0 * x)))))
	else:
		tmp = math.cos((eps + x)) - math.cos(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.00016)
		tmp = Float64(-2.0 * Float64(Float64(0.5 * eps) * sin(Float64(0.5 * Float64(eps - Float64(-2.0 * x))))));
	else
		tmp = Float64(cos(Float64(eps + x)) - cos(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.00016)
		tmp = -2.0 * ((0.5 * eps) * sin((0.5 * (eps - (-2.0 * x)))));
	else
		tmp = cos((eps + x)) - cos(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.00016], N[(-2.0 * N[(N[(0.5 * eps), $MachinePrecision] * N[Sin[N[(0.5 * N[(eps - N[(-2.0 * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.00016:\\
\;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 1.60000000000000013e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. diff-cos84.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    4. Applied egg-rr84.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    5. Step-by-step derivation
      1. associate-*r*84.7%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative84.7%

        \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot -2\right)} \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \]
      3. associate-*l*84.7%

        \[\leadsto \color{blue}{\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
      4. *-commutative84.7%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon - x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      5. associate-+r-84.7%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      6. +-commutative84.7%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      7. associate--l+99.8%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      8. +-inverses99.8%

        \[\leadsto \sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      9. distribute-lft-in99.8%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      10. metadata-eval99.8%

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

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

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      13. count-299.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right)\right) \]
      14. fma-define99.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right)\right) \]
    6. Simplified99.8%

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

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)} \]
    8. Taylor expanded in eps around 0 99.6%

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

    if 1.60000000000000013e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification98.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00016:\\ \;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) - \cos x\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 97.6% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000186:\\ \;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.000186)
   (* -2.0 (* (* 0.5 eps) (sin (* 0.5 (- eps (* -2.0 x))))))
   (+ (cos (* eps (+ (+ 2.0 (/ x eps)) -1.0))) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.000186) {
		tmp = -2.0 * ((0.5 * eps) * sin((0.5 * (eps - (-2.0 * x)))));
	} else {
		tmp = cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.000186d0) then
        tmp = (-2.0d0) * ((0.5d0 * eps) * sin((0.5d0 * (eps - ((-2.0d0) * x)))))
    else
        tmp = cos((eps * ((2.0d0 + (x / eps)) + (-1.0d0)))) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.000186) {
		tmp = -2.0 * ((0.5 * eps) * Math.sin((0.5 * (eps - (-2.0 * x)))));
	} else {
		tmp = Math.cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.000186:
		tmp = -2.0 * ((0.5 * eps) * math.sin((0.5 * (eps - (-2.0 * x)))))
	else:
		tmp = math.cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.000186)
		tmp = Float64(-2.0 * Float64(Float64(0.5 * eps) * sin(Float64(0.5 * Float64(eps - Float64(-2.0 * x))))));
	else
		tmp = Float64(cos(Float64(eps * Float64(Float64(2.0 + Float64(x / eps)) + -1.0))) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.000186)
		tmp = -2.0 * ((0.5 * eps) * sin((0.5 * (eps - (-2.0 * x)))));
	else
		tmp = cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.000186], N[(-2.0 * N[(N[(0.5 * eps), $MachinePrecision] * N[Sin[N[(0.5 * N[(eps - N[(-2.0 * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps * N[(N[(2.0 + N[(x / eps), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.000186:\\
\;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 1.85999999999999995e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. diff-cos84.7%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval84.7%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    4. Applied egg-rr84.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    5. Step-by-step derivation
      1. associate-*r*84.7%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative84.7%

        \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot -2\right)} \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \]
      3. associate-*l*84.7%

        \[\leadsto \color{blue}{\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
      4. *-commutative84.7%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(x + \left(\varepsilon - x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      5. associate-+r-84.7%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      6. +-commutative84.7%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      7. associate--l+99.8%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x - x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      8. +-inverses99.8%

        \[\leadsto \sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      9. distribute-lft-in99.8%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \varepsilon + 0.5 \cdot 0\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \]
      10. metadata-eval99.8%

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

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

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      13. count-299.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right)\right) \]
      14. fma-define99.8%

        \[\leadsto \sin \left(0.5 \cdot \varepsilon + 0\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right)\right) \]
    6. Simplified99.8%

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

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)} \]
    8. Taylor expanded in eps around 0 99.6%

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

    if 1.85999999999999995e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 68.1%

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{1} \]
    4. Taylor expanded in eps around inf 68.1%

      \[\leadsto \cos \color{blue}{\left(\varepsilon \cdot \left(1 + \frac{x}{\varepsilon}\right)\right)} - 1 \]
    5. Step-by-step derivation
      1. expm1-log1p-u68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)\right)}\right) - 1 \]
      2. expm1-undefine68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} - 1\right)}\right) - 1 \]
    6. Applied egg-rr68.0%

      \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} - 1\right)}\right) - 1 \]
    7. Step-by-step derivation
      1. sub-neg68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} + \left(-1\right)\right)}\right) - 1 \]
      2. metadata-eval68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} + \color{blue}{-1}\right)\right) - 1 \]
      3. +-commutative68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(-1 + e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)}\right)}\right) - 1 \]
      4. log1p-undefine68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + e^{\color{blue}{\log \left(1 + \left(1 + \frac{x}{\varepsilon}\right)\right)}}\right)\right) - 1 \]
      5. rem-exp-log68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \color{blue}{\left(1 + \left(1 + \frac{x}{\varepsilon}\right)\right)}\right)\right) - 1 \]
      6. associate-+r+68.1%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \color{blue}{\left(\left(1 + 1\right) + \frac{x}{\varepsilon}\right)}\right)\right) - 1 \]
      7. metadata-eval68.1%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \left(\color{blue}{2} + \frac{x}{\varepsilon}\right)\right)\right) - 1 \]
    8. Simplified68.1%

      \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(-1 + \left(2 + \frac{x}{\varepsilon}\right)\right)}\right) - 1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000186:\\ \;\;\;\;-2 \cdot \left(\left(0.5 \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon - -2 \cdot x\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 97.3% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000222:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.000222)
   (* eps (- (* eps -0.5) (sin x)))
   (+ (cos (* eps (+ (+ 2.0 (/ x eps)) -1.0))) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.000222) {
		tmp = eps * ((eps * -0.5) - sin(x));
	} else {
		tmp = cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.000222d0) then
        tmp = eps * ((eps * (-0.5d0)) - sin(x))
    else
        tmp = cos((eps * ((2.0d0 + (x / eps)) + (-1.0d0)))) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.000222) {
		tmp = eps * ((eps * -0.5) - Math.sin(x));
	} else {
		tmp = Math.cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.000222:
		tmp = eps * ((eps * -0.5) - math.sin(x))
	else:
		tmp = math.cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.000222)
		tmp = Float64(eps * Float64(Float64(eps * -0.5) - sin(x)));
	else
		tmp = Float64(cos(Float64(eps * Float64(Float64(2.0 + Float64(x / eps)) + -1.0))) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.000222)
		tmp = eps * ((eps * -0.5) - sin(x));
	else
		tmp = cos((eps * ((2.0 + (x / eps)) + -1.0))) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.000222], N[(eps * N[(N[(eps * -0.5), $MachinePrecision] - N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps * N[(N[(2.0 + N[(x / eps), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.000222:\\
\;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 2.22000000000000002e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. associate-*r*99.6%

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

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
    6. Taylor expanded in x around 0 99.2%

      \[\leadsto \varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \color{blue}{1} - \sin x\right) \]

    if 2.22000000000000002e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 68.1%

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{1} \]
    4. Taylor expanded in eps around inf 68.1%

      \[\leadsto \cos \color{blue}{\left(\varepsilon \cdot \left(1 + \frac{x}{\varepsilon}\right)\right)} - 1 \]
    5. Step-by-step derivation
      1. expm1-log1p-u68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)\right)}\right) - 1 \]
      2. expm1-undefine68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} - 1\right)}\right) - 1 \]
    6. Applied egg-rr68.0%

      \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} - 1\right)}\right) - 1 \]
    7. Step-by-step derivation
      1. sub-neg68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} + \left(-1\right)\right)}\right) - 1 \]
      2. metadata-eval68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)} + \color{blue}{-1}\right)\right) - 1 \]
      3. +-commutative68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(-1 + e^{\mathsf{log1p}\left(1 + \frac{x}{\varepsilon}\right)}\right)}\right) - 1 \]
      4. log1p-undefine68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + e^{\color{blue}{\log \left(1 + \left(1 + \frac{x}{\varepsilon}\right)\right)}}\right)\right) - 1 \]
      5. rem-exp-log68.0%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \color{blue}{\left(1 + \left(1 + \frac{x}{\varepsilon}\right)\right)}\right)\right) - 1 \]
      6. associate-+r+68.1%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \color{blue}{\left(\left(1 + 1\right) + \frac{x}{\varepsilon}\right)}\right)\right) - 1 \]
      7. metadata-eval68.1%

        \[\leadsto \cos \left(\varepsilon \cdot \left(-1 + \left(\color{blue}{2} + \frac{x}{\varepsilon}\right)\right)\right) - 1 \]
    8. Simplified68.1%

      \[\leadsto \cos \left(\varepsilon \cdot \color{blue}{\left(-1 + \left(2 + \frac{x}{\varepsilon}\right)\right)}\right) - 1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.000222:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\left(2 + \frac{x}{\varepsilon}\right) + -1\right)\right) + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 97.2% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00018:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\frac{x}{\varepsilon} + 1\right)\right) + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.00018)
   (* eps (- (* eps -0.5) (sin x)))
   (+ (cos (* eps (+ (/ x eps) 1.0))) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00018) {
		tmp = eps * ((eps * -0.5) - sin(x));
	} else {
		tmp = cos((eps * ((x / eps) + 1.0))) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.00018d0) then
        tmp = eps * ((eps * (-0.5d0)) - sin(x))
    else
        tmp = cos((eps * ((x / eps) + 1.0d0))) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00018) {
		tmp = eps * ((eps * -0.5) - Math.sin(x));
	} else {
		tmp = Math.cos((eps * ((x / eps) + 1.0))) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.00018:
		tmp = eps * ((eps * -0.5) - math.sin(x))
	else:
		tmp = math.cos((eps * ((x / eps) + 1.0))) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.00018)
		tmp = Float64(eps * Float64(Float64(eps * -0.5) - sin(x)));
	else
		tmp = Float64(cos(Float64(eps * Float64(Float64(x / eps) + 1.0))) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.00018)
		tmp = eps * ((eps * -0.5) - sin(x));
	else
		tmp = cos((eps * ((x / eps) + 1.0))) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.00018], N[(eps * N[(N[(eps * -0.5), $MachinePrecision] - N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps * N[(N[(x / eps), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.00018:\\
\;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \left(\varepsilon \cdot \left(\frac{x}{\varepsilon} + 1\right)\right) + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 1.80000000000000011e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. associate-*r*99.6%

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

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
    6. Taylor expanded in x around 0 99.2%

      \[\leadsto \varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \color{blue}{1} - \sin x\right) \]

    if 1.80000000000000011e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 68.1%

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{1} \]
    4. Taylor expanded in eps around inf 68.1%

      \[\leadsto \cos \color{blue}{\left(\varepsilon \cdot \left(1 + \frac{x}{\varepsilon}\right)\right)} - 1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00018:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon \cdot \left(\frac{x}{\varepsilon} + 1\right)\right) + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 97.3% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00026:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.00026)
   (* eps (- (* eps -0.5) (sin x)))
   (+ (cos (+ eps x)) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00026) {
		tmp = eps * ((eps * -0.5) - sin(x));
	} else {
		tmp = cos((eps + x)) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.00026d0) then
        tmp = eps * ((eps * (-0.5d0)) - sin(x))
    else
        tmp = cos((eps + x)) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.00026) {
		tmp = eps * ((eps * -0.5) - Math.sin(x));
	} else {
		tmp = Math.cos((eps + x)) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.00026:
		tmp = eps * ((eps * -0.5) - math.sin(x))
	else:
		tmp = math.cos((eps + x)) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.00026)
		tmp = Float64(eps * Float64(Float64(eps * -0.5) - sin(x)));
	else
		tmp = Float64(cos(Float64(eps + x)) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.00026)
		tmp = eps * ((eps * -0.5) - sin(x));
	else
		tmp = cos((eps + x)) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.00026], N[(eps * N[(N[(eps * -0.5), $MachinePrecision] - N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.00026:\\
\;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \left(\varepsilon + x\right) + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 2.59999999999999977e-4

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. associate-*r*99.6%

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

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
    6. Taylor expanded in x around 0 99.2%

      \[\leadsto \varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \color{blue}{1} - \sin x\right) \]

    if 2.59999999999999977e-4 < eps

    1. Initial program 82.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 68.1%

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.00026:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 - \sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 96.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 9 \cdot 10^{-6}:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 9e-6)
   (*
    eps
    (+
     (* eps -0.5)
     (* x (+ (* x (+ (* eps 0.25) (* x 0.16666666666666666))) -1.0))))
   (+ (cos (+ eps x)) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 9e-6) {
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	} else {
		tmp = cos((eps + x)) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 9d-6) then
        tmp = eps * ((eps * (-0.5d0)) + (x * ((x * ((eps * 0.25d0) + (x * 0.16666666666666666d0))) + (-1.0d0))))
    else
        tmp = cos((eps + x)) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 9e-6) {
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	} else {
		tmp = Math.cos((eps + x)) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 9e-6:
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)))
	else:
		tmp = math.cos((eps + x)) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 9e-6)
		tmp = Float64(eps * Float64(Float64(eps * -0.5) + Float64(x * Float64(Float64(x * Float64(Float64(eps * 0.25) + Float64(x * 0.16666666666666666))) + -1.0))));
	else
		tmp = Float64(cos(Float64(eps + x)) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 9e-6)
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	else
		tmp = cos((eps + x)) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 9e-6], N[(eps * N[(N[(eps * -0.5), $MachinePrecision] + N[(x * N[(N[(x * N[(N[(eps * 0.25), $MachinePrecision] + N[(x * 0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 9 \cdot 10^{-6}:\\
\;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \left(\varepsilon + x\right) + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 9.00000000000000023e-6

    1. Initial program 55.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in eps around 0 99.7%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. associate-*r*99.7%

        \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
    6. Taylor expanded in x around 0 99.3%

      \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \left(0.16666666666666666 \cdot x + 0.25 \cdot \varepsilon\right) - 1\right)\right)} \]

    if 9.00000000000000023e-6 < eps

    1. Initial program 80.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 64.1%

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 9 \cdot 10^{-6}:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \left(\varepsilon + x\right) + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 10: 96.2% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.0027:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon + -1\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps 0.0027)
   (*
    eps
    (+
     (* eps -0.5)
     (* x (+ (* x (+ (* eps 0.25) (* x 0.16666666666666666))) -1.0))))
   (+ (cos eps) -1.0)))
double code(double x, double eps) {
	double tmp;
	if (eps <= 0.0027) {
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	} else {
		tmp = cos(eps) + -1.0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= 0.0027d0) then
        tmp = eps * ((eps * (-0.5d0)) + (x * ((x * ((eps * 0.25d0) + (x * 0.16666666666666666d0))) + (-1.0d0))))
    else
        tmp = cos(eps) + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= 0.0027) {
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	} else {
		tmp = Math.cos(eps) + -1.0;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= 0.0027:
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)))
	else:
		tmp = math.cos(eps) + -1.0
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= 0.0027)
		tmp = Float64(eps * Float64(Float64(eps * -0.5) + Float64(x * Float64(Float64(x * Float64(Float64(eps * 0.25) + Float64(x * 0.16666666666666666))) + -1.0))));
	else
		tmp = Float64(cos(eps) + -1.0);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= 0.0027)
		tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
	else
		tmp = cos(eps) + -1.0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, 0.0027], N[(eps * N[(N[(eps * -0.5), $MachinePrecision] + N[(x * N[(N[(x * N[(N[(eps * 0.25), $MachinePrecision] + N[(x * 0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq 0.0027:\\
\;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\cos \varepsilon + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < 0.0027000000000000001

    1. Initial program 55.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in eps around 0 99.4%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. associate-*r*99.4%

        \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
    5. Simplified99.4%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
    6. Taylor expanded in x around 0 98.7%

      \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \left(0.16666666666666666 \cdot x + 0.25 \cdot \varepsilon\right) - 1\right)\right)} \]

    if 0.0027000000000000001 < eps

    1. Initial program 83.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 61.1%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq 0.0027:\\ \;\;\;\;\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 11: 95.0% accurate, 10.8× speedup?

\[\begin{array}{l} \\ \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (*
  eps
  (+
   (* eps -0.5)
   (* x (+ (* x (+ (* eps 0.25) (* x 0.16666666666666666))) -1.0)))))
double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = eps * ((eps * (-0.5d0)) + (x * ((x * ((eps * 0.25d0) + (x * 0.16666666666666666d0))) + (-1.0d0))))
end function
public static double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
}
def code(x, eps):
	return eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)))
function code(x, eps)
	return Float64(eps * Float64(Float64(eps * -0.5) + Float64(x * Float64(Float64(x * Float64(Float64(eps * 0.25) + Float64(x * 0.16666666666666666))) + -1.0))))
end
function tmp = code(x, eps)
	tmp = eps * ((eps * -0.5) + (x * ((x * ((eps * 0.25) + (x * 0.16666666666666666))) + -1.0)));
end
code[x_, eps_] := N[(eps * N[(N[(eps * -0.5), $MachinePrecision] + N[(x * N[(N[(x * N[(N[(eps * 0.25), $MachinePrecision] + N[(x * 0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in eps around 0 95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
  4. Step-by-step derivation
    1. associate-*r*95.9%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
  6. Taylor expanded in x around 0 95.1%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \left(0.16666666666666666 \cdot x + 0.25 \cdot \varepsilon\right) - 1\right)\right)} \]
  7. Final simplification95.1%

    \[\leadsto \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(\varepsilon \cdot 0.25 + x \cdot 0.16666666666666666\right) + -1\right)\right) \]
  8. Add Preprocessing

Alternative 12: 94.9% accurate, 13.7× speedup?

\[\begin{array}{l} \\ \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(x \cdot 0.16666666666666666\right) + -1\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* eps (+ (* eps -0.5) (* x (+ (* x (* x 0.16666666666666666)) -1.0)))))
double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((x * (x * 0.16666666666666666)) + -1.0)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = eps * ((eps * (-0.5d0)) + (x * ((x * (x * 0.16666666666666666d0)) + (-1.0d0))))
end function
public static double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((x * (x * 0.16666666666666666)) + -1.0)));
}
def code(x, eps):
	return eps * ((eps * -0.5) + (x * ((x * (x * 0.16666666666666666)) + -1.0)))
function code(x, eps)
	return Float64(eps * Float64(Float64(eps * -0.5) + Float64(x * Float64(Float64(x * Float64(x * 0.16666666666666666)) + -1.0))))
end
function tmp = code(x, eps)
	tmp = eps * ((eps * -0.5) + (x * ((x * (x * 0.16666666666666666)) + -1.0)));
end
code[x_, eps_] := N[(eps * N[(N[(eps * -0.5), $MachinePrecision] + N[(x * N[(N[(x * N[(x * 0.16666666666666666), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(x \cdot 0.16666666666666666\right) + -1\right)\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in eps around 0 95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
  4. Step-by-step derivation
    1. associate-*r*95.9%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
  6. Taylor expanded in x around 0 95.1%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \left(0.16666666666666666 \cdot x + 0.25 \cdot \varepsilon\right) - 1\right)\right)} \]
  7. Taylor expanded in x around inf 95.1%

    \[\leadsto \varepsilon \cdot \left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \color{blue}{\left(0.16666666666666666 \cdot x\right)} - 1\right)\right) \]
  8. Step-by-step derivation
    1. *-commutative95.1%

      \[\leadsto \varepsilon \cdot \left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \color{blue}{\left(x \cdot 0.16666666666666666\right)} - 1\right)\right) \]
  9. Simplified95.1%

    \[\leadsto \varepsilon \cdot \left(-0.5 \cdot \varepsilon + x \cdot \left(x \cdot \color{blue}{\left(x \cdot 0.16666666666666666\right)} - 1\right)\right) \]
  10. Final simplification95.1%

    \[\leadsto \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(x \cdot \left(x \cdot 0.16666666666666666\right) + -1\right)\right) \]
  11. Add Preprocessing

Alternative 13: 94.5% accurate, 13.7× speedup?

\[\begin{array}{l} \\ \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(0.25 \cdot \left(\varepsilon \cdot x\right) + -1\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* eps (+ (* eps -0.5) (* x (+ (* 0.25 (* eps x)) -1.0)))))
double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((0.25 * (eps * x)) + -1.0)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = eps * ((eps * (-0.5d0)) + (x * ((0.25d0 * (eps * x)) + (-1.0d0))))
end function
public static double code(double x, double eps) {
	return eps * ((eps * -0.5) + (x * ((0.25 * (eps * x)) + -1.0)));
}
def code(x, eps):
	return eps * ((eps * -0.5) + (x * ((0.25 * (eps * x)) + -1.0)))
function code(x, eps)
	return Float64(eps * Float64(Float64(eps * -0.5) + Float64(x * Float64(Float64(0.25 * Float64(eps * x)) + -1.0))))
end
function tmp = code(x, eps)
	tmp = eps * ((eps * -0.5) + (x * ((0.25 * (eps * x)) + -1.0)));
end
code[x_, eps_] := N[(eps * N[(N[(eps * -0.5), $MachinePrecision] + N[(x * N[(N[(0.25 * N[(eps * x), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(0.25 \cdot \left(\varepsilon \cdot x\right) + -1\right)\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in eps around 0 95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
  4. Step-by-step derivation
    1. associate-*r*95.9%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
  6. Taylor expanded in x around 0 94.7%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + x \cdot \left(0.25 \cdot \left(\varepsilon \cdot x\right) - 1\right)\right)} \]
  7. Final simplification94.7%

    \[\leadsto \varepsilon \cdot \left(\varepsilon \cdot -0.5 + x \cdot \left(0.25 \cdot \left(\varepsilon \cdot x\right) + -1\right)\right) \]
  8. Add Preprocessing

Alternative 14: 94.4% accurate, 29.3× speedup?

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

\\
\varepsilon \cdot \left(\varepsilon \cdot -0.5 - x\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in eps around 0 95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
  4. Step-by-step derivation
    1. associate-*r*95.9%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
  6. Taylor expanded in x around 0 94.7%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(-1 \cdot x + -0.5 \cdot \varepsilon\right)} \]
  7. Step-by-step derivation
    1. +-commutative94.7%

      \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon + -1 \cdot x\right)} \]
    2. mul-1-neg94.7%

      \[\leadsto \varepsilon \cdot \left(-0.5 \cdot \varepsilon + \color{blue}{\left(-x\right)}\right) \]
    3. unsub-neg94.7%

      \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon - x\right)} \]
    4. *-commutative94.7%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\varepsilon \cdot -0.5} - x\right) \]
  8. Simplified94.7%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(\varepsilon \cdot -0.5 - x\right)} \]
  9. Add Preprocessing

Alternative 15: 51.2% accurate, 41.0× speedup?

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

\\
\varepsilon \cdot \left(\varepsilon \cdot -0.5\right)
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in eps around 0 95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(-0.5 \cdot \left(\varepsilon \cdot \cos x\right) - \sin x\right)} \]
  4. Step-by-step derivation
    1. associate-*r*95.9%

      \[\leadsto \varepsilon \cdot \left(\color{blue}{\left(-0.5 \cdot \varepsilon\right) \cdot \cos x} - \sin x\right) \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(-0.5 \cdot \varepsilon\right) \cdot \cos x - \sin x\right)} \]
  6. Taylor expanded in x around 0 54.4%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(-0.5 \cdot \varepsilon\right)} \]
  7. Step-by-step derivation
    1. *-commutative54.4%

      \[\leadsto \varepsilon \cdot \color{blue}{\left(\varepsilon \cdot -0.5\right)} \]
  8. Simplified54.4%

    \[\leadsto \varepsilon \cdot \color{blue}{\left(\varepsilon \cdot -0.5\right)} \]
  9. Add Preprocessing

Alternative 16: 48.8% accurate, 205.0× speedup?

\[\begin{array}{l} \\ 0 \end{array} \]
(FPCore (x eps) :precision binary64 0.0)
double code(double x, double eps) {
	return 0.0;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = 0.0d0
end function
public static double code(double x, double eps) {
	return 0.0;
}
def code(x, eps):
	return 0.0
function code(x, eps)
	return 0.0
end
function tmp = code(x, eps)
	tmp = 0.0;
end
code[x_, eps_] := 0.0
\begin{array}{l}

\\
0
\end{array}
Derivation
  1. Initial program 56.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0 54.7%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  4. Taylor expanded in eps around 0 51.8%

    \[\leadsto \color{blue}{1} - 1 \]
  5. Step-by-step derivation
    1. metadata-eval51.8%

      \[\leadsto \color{blue}{0} \]
  6. Applied egg-rr51.8%

    \[\leadsto \color{blue}{0} \]
  7. Add Preprocessing

Developer Target 1: 99.3% accurate, 1.0× speedup?

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

\\
\left(-2 \cdot \sin \left(x + \frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon}{2}\right)
\end{array}

Developer Target 2: 98.3% accurate, 0.4× speedup?

\[\begin{array}{l} \\ {\left(\sqrt[3]{\left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)}\right)}^{3} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (pow (cbrt (* (* -2.0 (sin (* 0.5 (fma 2.0 x eps)))) (sin (* 0.5 eps)))) 3.0))
double code(double x, double eps) {
	return pow(cbrt(((-2.0 * sin((0.5 * fma(2.0, x, eps)))) * sin((0.5 * eps)))), 3.0);
}
function code(x, eps)
	return cbrt(Float64(Float64(-2.0 * sin(Float64(0.5 * fma(2.0, x, eps)))) * sin(Float64(0.5 * eps)))) ^ 3.0
end
code[x_, eps_] := N[Power[N[Power[N[(N[(-2.0 * N[Sin[N[(0.5 * N[(2.0 * x + eps), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sin[N[(0.5 * eps), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision], 3.0], $MachinePrecision]
\begin{array}{l}

\\
{\left(\sqrt[3]{\left(-2 \cdot \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)}\right)}^{3}
\end{array}

Reproduce

?
herbie shell --seed 2024169 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  :pre (and (and (and (<= -10000.0 x) (<= x 10000.0)) (< (* 1e-16 (fabs x)) eps)) (< eps (fabs x)))

  :alt
  (! :herbie-platform default (* -2 (sin (+ x (/ eps 2))) (sin (/ eps 2))))

  :alt
  (! :herbie-platform default (pow (cbrt (* -2 (sin (* 1/2 (fma 2 x eps))) (sin (* 1/2 eps)))) 3))

  (- (cos (+ x eps)) (cos x)))