2cos (problem 3.3.5)

Percentage Accurate: 37.8% → 99.2%
Time: 21.5s
Alternatives: 17
Speedup: 2.0×

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 17 alternatives:

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

Initial Program: 37.8% 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: 99.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0028:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, -\mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 0.0024:\\ \;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.0028)
   (fma (cos x) (cos eps) (- (fma (sin eps) (sin x) (cos x))))
   (if (<= eps 0.0024)
     (-
      (+
       (* 0.16666666666666666 (* (sin x) (pow eps 3.0)))
       (*
        (cos x)
        (+ (* -0.5 (pow eps 2.0)) (* 0.041666666666666664 (pow eps 4.0)))))
      (* eps (sin x)))
     (- (fma (cos x) (cos eps) (* (sin eps) (- (sin x)))) (cos x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.0028) {
		tmp = fma(cos(x), cos(eps), -fma(sin(eps), sin(x), cos(x)));
	} else if (eps <= 0.0024) {
		tmp = ((0.16666666666666666 * (sin(x) * pow(eps, 3.0))) + (cos(x) * ((-0.5 * pow(eps, 2.0)) + (0.041666666666666664 * pow(eps, 4.0))))) - (eps * sin(x));
	} else {
		tmp = fma(cos(x), cos(eps), (sin(eps) * -sin(x))) - cos(x);
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.0028)
		tmp = fma(cos(x), cos(eps), Float64(-fma(sin(eps), sin(x), cos(x))));
	elseif (eps <= 0.0024)
		tmp = Float64(Float64(Float64(0.16666666666666666 * Float64(sin(x) * (eps ^ 3.0))) + Float64(cos(x) * Float64(Float64(-0.5 * (eps ^ 2.0)) + Float64(0.041666666666666664 * (eps ^ 4.0))))) - Float64(eps * sin(x)));
	else
		tmp = Float64(fma(cos(x), cos(eps), Float64(sin(eps) * Float64(-sin(x)))) - cos(x));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -0.0028], N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + (-N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[Cos[x], $MachinePrecision]), $MachinePrecision])), $MachinePrecision], If[LessEqual[eps, 0.0024], N[(N[(N[(0.16666666666666666 * N[(N[Sin[x], $MachinePrecision] * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision] + N[(0.041666666666666664 * N[Power[eps, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0028:\\
\;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, -\mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\right)\\

\mathbf{elif}\;\varepsilon \leq 0.0024:\\
\;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.00279999999999999997

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg42.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative42.1%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+98.5%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\cos x\right)\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
      2. unsub-neg98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \cos x\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \cos x\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    6. Step-by-step derivation
      1. associate-+l-98.4%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\cos x - \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
      2. fma-neg98.5%

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

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\cos x - \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon}\right)\right) \]
      4. cancel-sign-sub98.5%

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

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

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\color{blue}{\sin \varepsilon \cdot \sin x} + \cos x\right)\right) \]
      7. fma-def98.5%

        \[\leadsto \mathsf{fma}\left(\cos x, \cos \varepsilon, -\color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)}\right) \]
    7. Applied egg-rr98.5%

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

    if -0.00279999999999999997 < eps < 0.00239999999999999979

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.8%

        \[\leadsto \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.8%

        \[\leadsto \color{blue}{\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) - \varepsilon \cdot \sin x} \]
      4. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)} - \varepsilon \cdot \sin x \]
      5. +-commutative99.8%

        \[\leadsto \color{blue}{\left(0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right)} - \varepsilon \cdot \sin x \]
      6. *-commutative99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \color{blue}{\left(\sin x \cdot {\varepsilon}^{3}\right)} + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right) - \varepsilon \cdot \sin x \]
      7. associate-*r*99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \left(\color{blue}{\left(-0.5 \cdot {\varepsilon}^{2}\right) \cdot \cos x} + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right) - \varepsilon \cdot \sin x \]
      8. associate-*r*99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \left(\left(-0.5 \cdot {\varepsilon}^{2}\right) \cdot \cos x + \color{blue}{\left(0.041666666666666664 \cdot {\varepsilon}^{4}\right) \cdot \cos x}\right)\right) - \varepsilon \cdot \sin x \]
      9. distribute-rgt-out99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)}\right) - \varepsilon \cdot \sin x \]
    4. Simplified99.8%

      \[\leadsto \color{blue}{\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x} \]

    if 0.00239999999999999979 < eps

    1. Initial program 57.1%

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

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

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0028:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, -\mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 0.0024:\\ \;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \]

Alternative 2: 99.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0025:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 0.0024:\\ \;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.0025)
   (- (- (* (cos x) (cos eps)) (cos x)) (* (sin eps) (sin x)))
   (if (<= eps 0.0024)
     (-
      (+
       (* 0.16666666666666666 (* (sin x) (pow eps 3.0)))
       (*
        (cos x)
        (+ (* -0.5 (pow eps 2.0)) (* 0.041666666666666664 (pow eps 4.0)))))
      (* eps (sin x)))
     (- (fma (cos x) (cos eps) (* (sin eps) (- (sin x)))) (cos x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.0025) {
		tmp = ((cos(x) * cos(eps)) - cos(x)) - (sin(eps) * sin(x));
	} else if (eps <= 0.0024) {
		tmp = ((0.16666666666666666 * (sin(x) * pow(eps, 3.0))) + (cos(x) * ((-0.5 * pow(eps, 2.0)) + (0.041666666666666664 * pow(eps, 4.0))))) - (eps * sin(x));
	} else {
		tmp = fma(cos(x), cos(eps), (sin(eps) * -sin(x))) - cos(x);
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.0025)
		tmp = Float64(Float64(Float64(cos(x) * cos(eps)) - cos(x)) - Float64(sin(eps) * sin(x)));
	elseif (eps <= 0.0024)
		tmp = Float64(Float64(Float64(0.16666666666666666 * Float64(sin(x) * (eps ^ 3.0))) + Float64(cos(x) * Float64(Float64(-0.5 * (eps ^ 2.0)) + Float64(0.041666666666666664 * (eps ^ 4.0))))) - Float64(eps * sin(x)));
	else
		tmp = Float64(fma(cos(x), cos(eps), Float64(sin(eps) * Float64(-sin(x)))) - cos(x));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -0.0025], N[(N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.0024], N[(N[(N[(0.16666666666666666 * N[(N[Sin[x], $MachinePrecision] * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision] + N[(0.041666666666666664 * N[Power[eps, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0025:\\
\;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\

\mathbf{elif}\;\varepsilon \leq 0.0024:\\
\;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.00250000000000000005

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg42.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative42.1%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+98.5%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\cos x\right)\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
      2. unsub-neg98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \cos x\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Applied egg-rr98.5%

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

    if -0.00250000000000000005 < eps < 0.00239999999999999979

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto \color{blue}{\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.8%

        \[\leadsto \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.8%

        \[\leadsto \color{blue}{\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \left(0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)\right) - \varepsilon \cdot \sin x} \]
      4. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right) + 0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right)\right)} - \varepsilon \cdot \sin x \]
      5. +-commutative99.8%

        \[\leadsto \color{blue}{\left(0.16666666666666666 \cdot \left({\varepsilon}^{3} \cdot \sin x\right) + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right)} - \varepsilon \cdot \sin x \]
      6. *-commutative99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \color{blue}{\left(\sin x \cdot {\varepsilon}^{3}\right)} + \left(-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right) - \varepsilon \cdot \sin x \]
      7. associate-*r*99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \left(\color{blue}{\left(-0.5 \cdot {\varepsilon}^{2}\right) \cdot \cos x} + 0.041666666666666664 \cdot \left({\varepsilon}^{4} \cdot \cos x\right)\right)\right) - \varepsilon \cdot \sin x \]
      8. associate-*r*99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \left(\left(-0.5 \cdot {\varepsilon}^{2}\right) \cdot \cos x + \color{blue}{\left(0.041666666666666664 \cdot {\varepsilon}^{4}\right) \cdot \cos x}\right)\right) - \varepsilon \cdot \sin x \]
      9. distribute-rgt-out99.8%

        \[\leadsto \left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)}\right) - \varepsilon \cdot \sin x \]
    4. Simplified99.8%

      \[\leadsto \color{blue}{\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x} \]

    if 0.00239999999999999979 < eps

    1. Initial program 57.1%

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

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

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0025:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 0.0024:\\ \;\;\;\;\left(0.16666666666666666 \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2} + 0.041666666666666664 \cdot {\varepsilon}^{4}\right)\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \]

Alternative 3: 99.1% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 3 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -4.1e-5)
   (- (- (* (cos x) (cos eps)) (cos x)) (* (sin eps) (sin x)))
   (if (<= eps 3e-5)
     (- (* (cos x) (* -0.5 (pow eps 2.0))) (* eps (sin x)))
     (- (fma (cos x) (cos eps) (* (sin eps) (- (sin x)))) (cos x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -4.1e-5) {
		tmp = ((cos(x) * cos(eps)) - cos(x)) - (sin(eps) * sin(x));
	} else if (eps <= 3e-5) {
		tmp = (cos(x) * (-0.5 * pow(eps, 2.0))) - (eps * sin(x));
	} else {
		tmp = fma(cos(x), cos(eps), (sin(eps) * -sin(x))) - cos(x);
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -4.1e-5)
		tmp = Float64(Float64(Float64(cos(x) * cos(eps)) - cos(x)) - Float64(sin(eps) * sin(x)));
	elseif (eps <= 3e-5)
		tmp = Float64(Float64(cos(x) * Float64(-0.5 * (eps ^ 2.0))) - Float64(eps * sin(x)));
	else
		tmp = Float64(fma(cos(x), cos(eps), Float64(sin(eps) * Float64(-sin(x)))) - cos(x));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -4.1e-5], N[(N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 3e-5], N[(N[(N[Cos[x], $MachinePrecision] * N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5}:\\
\;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\

\mathbf{elif}\;\varepsilon \leq 3 \cdot 10^{-5}:\\
\;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -4.10000000000000005e-5

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg42.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative42.1%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+98.5%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\cos x\right)\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
      2. unsub-neg98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \cos x\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Applied egg-rr98.5%

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

    if -4.10000000000000005e-5 < eps < 3.00000000000000008e-5

    1. Initial program 20.6%

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

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      4. associate-*r*99.7%

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

        \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.7%

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

    if 3.00000000000000008e-5 < eps

    1. Initial program 57.1%

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

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

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

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

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 3 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \end{array} \]

Alternative 4: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.6 \cdot 10^{-5}\right):\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -4.1e-5) (not (<= eps 3.6e-5)))
   (fma (+ (cos eps) -1.0) (cos x) (* (sin eps) (- (sin x))))
   (- (* (cos x) (* -0.5 (pow eps 2.0))) (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -4.1e-5) || !(eps <= 3.6e-5)) {
		tmp = fma((cos(eps) + -1.0), cos(x), (sin(eps) * -sin(x)));
	} else {
		tmp = (cos(x) * (-0.5 * pow(eps, 2.0))) - (eps * sin(x));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if ((eps <= -4.1e-5) || !(eps <= 3.6e-5))
		tmp = fma(Float64(cos(eps) + -1.0), cos(x), Float64(sin(eps) * Float64(-sin(x))));
	else
		tmp = Float64(Float64(cos(x) * Float64(-0.5 * (eps ^ 2.0))) - Float64(eps * sin(x)));
	end
	return tmp
end
code[x_, eps_] := If[Or[LessEqual[eps, -4.1e-5], N[Not[LessEqual[eps, 3.6e-5]], $MachinePrecision]], N[(N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision] * N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.6 \cdot 10^{-5}\right):\\
\;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -4.10000000000000005e-5 or 3.60000000000000009e-5 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg50.7%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. cancel-sign-sub-inv98.5%

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

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

        \[\leadsto \cos x \cdot \cos \varepsilon + \left(\color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} + \left(-\cos x\right)\right) \]
    3. Applied egg-rr98.6%

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

        \[\leadsto \cos x \cdot \cos \varepsilon + \color{blue}{\left(\left(-\cos x\right) + \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
      2. distribute-rgt-neg-out98.6%

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

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

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

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

        \[\leadsto \left(\color{blue}{\cos \varepsilon \cdot \cos x} + \left(-\cos x\right)\right) - \sin x \cdot \sin \varepsilon \]
      7. neg-mul-198.7%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x + \color{blue}{-1 \cdot \cos x}\right) - \sin x \cdot \sin \varepsilon \]
      8. distribute-rgt-out98.6%

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

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

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

        \[\leadsto \color{blue}{\left(\cos \varepsilon + -1\right) \cdot \cos x} - \sin \varepsilon \cdot \sin x \]
      2. fma-neg98.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, -\sin \varepsilon \cdot \sin x\right)} \]
      3. distribute-rgt-neg-in98.6%

        \[\leadsto \mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)}\right) \]
    7. Applied egg-rr98.6%

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

    if -4.10000000000000005e-5 < eps < 3.60000000000000009e-5

    1. Initial program 20.6%

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

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      4. associate-*r*99.7%

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

        \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.7%

      \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3.6 \cdot 10^{-5}\right):\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 5: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.3 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.2 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -3.3e-5)
   (- (* (cos x) (cos eps)) (+ (cos x) (* (sin eps) (sin x))))
   (if (<= eps 4.2e-5)
     (- (* (cos x) (* -0.5 (pow eps 2.0))) (* eps (sin x)))
     (fma (+ (cos eps) -1.0) (cos x) (* (sin eps) (- (sin x)))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -3.3e-5) {
		tmp = (cos(x) * cos(eps)) - (cos(x) + (sin(eps) * sin(x)));
	} else if (eps <= 4.2e-5) {
		tmp = (cos(x) * (-0.5 * pow(eps, 2.0))) - (eps * sin(x));
	} else {
		tmp = fma((cos(eps) + -1.0), cos(x), (sin(eps) * -sin(x)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -3.3e-5)
		tmp = Float64(Float64(cos(x) * cos(eps)) - Float64(cos(x) + Float64(sin(eps) * sin(x))));
	elseif (eps <= 4.2e-5)
		tmp = Float64(Float64(cos(x) * Float64(-0.5 * (eps ^ 2.0))) - Float64(eps * sin(x)));
	else
		tmp = fma(Float64(cos(eps) + -1.0), cos(x), Float64(sin(eps) * Float64(-sin(x))));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -3.3e-5], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[(N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 4.2e-5], N[(N[(N[Cos[x], $MachinePrecision] * N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision] * N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -3.3 \cdot 10^{-5}:\\
\;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\

\mathbf{elif}\;\varepsilon \leq 4.2 \cdot 10^{-5}:\\
\;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -3.3000000000000003e-5

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg42.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative42.1%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+98.5%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.5%

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

        \[\leadsto \sin \varepsilon \cdot \left(-\sin x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\cos x\right)\right)} \]
      3. associate-+r+98.3%

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

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

        \[\leadsto \left(\cos x \cdot \cos \varepsilon + \color{blue}{\left(-\sin x\right) \cdot \sin \varepsilon}\right) + \left(-\cos x\right) \]
      6. cancel-sign-sub-inv98.3%

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

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \]
      8. associate--l-98.4%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)} \]
      9. +-commutative98.4%

        \[\leadsto \cos x \cdot \cos \varepsilon - \color{blue}{\left(\cos x + \sin x \cdot \sin \varepsilon\right)} \]
      10. *-commutative98.4%

        \[\leadsto \cos x \cdot \cos \varepsilon - \left(\cos x + \color{blue}{\sin \varepsilon \cdot \sin x}\right) \]
    5. Applied egg-rr98.4%

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

    if -3.3000000000000003e-5 < eps < 4.19999999999999977e-5

    1. Initial program 20.6%

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

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      4. associate-*r*99.7%

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

        \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.7%

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

    if 4.19999999999999977e-5 < eps

    1. Initial program 57.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg57.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.7%

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

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

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

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

      \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon + \left(\sin \varepsilon \cdot \left(-\sin x\right) + \left(-\cos x\right)\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.7%

        \[\leadsto \cos x \cdot \cos \varepsilon + \color{blue}{\left(\left(-\cos x\right) + \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
      2. distribute-rgt-neg-out98.7%

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

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

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

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

        \[\leadsto \left(\color{blue}{\cos \varepsilon \cdot \cos x} + \left(-\cos x\right)\right) - \sin x \cdot \sin \varepsilon \]
      7. neg-mul-198.8%

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

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

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

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

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, -\sin \varepsilon \cdot \sin x\right)} \]
      3. distribute-rgt-neg-in98.8%

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.3 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \cos \varepsilon - \left(\cos x + \sin \varepsilon \cdot \sin x\right)\\ \mathbf{elif}\;\varepsilon \leq 4.2 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \end{array} \]

Alternative 6: 99.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.8 \cdot 10^{-5}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 2.8 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -3.8e-5)
   (- (- (* (cos x) (cos eps)) (cos x)) (* (sin eps) (sin x)))
   (if (<= eps 2.8e-5)
     (- (* (cos x) (* -0.5 (pow eps 2.0))) (* eps (sin x)))
     (fma (+ (cos eps) -1.0) (cos x) (* (sin eps) (- (sin x)))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -3.8e-5) {
		tmp = ((cos(x) * cos(eps)) - cos(x)) - (sin(eps) * sin(x));
	} else if (eps <= 2.8e-5) {
		tmp = (cos(x) * (-0.5 * pow(eps, 2.0))) - (eps * sin(x));
	} else {
		tmp = fma((cos(eps) + -1.0), cos(x), (sin(eps) * -sin(x)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -3.8e-5)
		tmp = Float64(Float64(Float64(cos(x) * cos(eps)) - cos(x)) - Float64(sin(eps) * sin(x)));
	elseif (eps <= 2.8e-5)
		tmp = Float64(Float64(cos(x) * Float64(-0.5 * (eps ^ 2.0))) - Float64(eps * sin(x)));
	else
		tmp = fma(Float64(cos(eps) + -1.0), cos(x), Float64(sin(eps) * Float64(-sin(x))));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -3.8e-5], N[(N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 2.8e-5], N[(N[(N[Cos[x], $MachinePrecision] * N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision] * N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -3.8 \cdot 10^{-5}:\\
\;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -3.8000000000000002e-5

    1. Initial program 42.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg42.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative42.1%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv98.3%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+98.5%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\cos x\right)\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
      2. unsub-neg98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \cos x\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Applied egg-rr98.5%

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

    if -3.8000000000000002e-5 < eps < 2.79999999999999996e-5

    1. Initial program 20.6%

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

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      4. associate-*r*99.7%

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

        \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.7%

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

    if 2.79999999999999996e-5 < eps

    1. Initial program 57.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg57.1%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.7%

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

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

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

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

      \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon + \left(\sin \varepsilon \cdot \left(-\sin x\right) + \left(-\cos x\right)\right)} \]
    4. Step-by-step derivation
      1. +-commutative98.7%

        \[\leadsto \cos x \cdot \cos \varepsilon + \color{blue}{\left(\left(-\cos x\right) + \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
      2. distribute-rgt-neg-out98.7%

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

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

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

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

        \[\leadsto \left(\color{blue}{\cos \varepsilon \cdot \cos x} + \left(-\cos x\right)\right) - \sin x \cdot \sin \varepsilon \]
      7. neg-mul-198.8%

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

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

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

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

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, -\sin \varepsilon \cdot \sin x\right)} \]
      3. distribute-rgt-neg-in98.8%

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3.8 \cdot 10^{-5}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{elif}\;\varepsilon \leq 2.8 \cdot 10^{-5}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\cos \varepsilon + -1, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \end{array} \]

Alternative 7: 99.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3 \cdot 10^{-5}\right):\\ \;\;\;\;\cos x \cdot \left(\cos \varepsilon + -1\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -4.4e-5) (not (<= eps 3e-5)))
   (- (* (cos x) (+ (cos eps) -1.0)) (* (sin eps) (sin x)))
   (- (* (cos x) (* -0.5 (pow eps 2.0))) (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -4.4e-5) || !(eps <= 3e-5)) {
		tmp = (cos(x) * (cos(eps) + -1.0)) - (sin(eps) * sin(x));
	} else {
		tmp = (cos(x) * (-0.5 * pow(eps, 2.0))) - (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 <= (-4.4d-5)) .or. (.not. (eps <= 3d-5))) then
        tmp = (cos(x) * (cos(eps) + (-1.0d0))) - (sin(eps) * sin(x))
    else
        tmp = (cos(x) * ((-0.5d0) * (eps ** 2.0d0))) - (eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -4.4e-5) || !(eps <= 3e-5)) {
		tmp = (Math.cos(x) * (Math.cos(eps) + -1.0)) - (Math.sin(eps) * Math.sin(x));
	} else {
		tmp = (Math.cos(x) * (-0.5 * Math.pow(eps, 2.0))) - (eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -4.4e-5) or not (eps <= 3e-5):
		tmp = (math.cos(x) * (math.cos(eps) + -1.0)) - (math.sin(eps) * math.sin(x))
	else:
		tmp = (math.cos(x) * (-0.5 * math.pow(eps, 2.0))) - (eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -4.4e-5) || !(eps <= 3e-5))
		tmp = Float64(Float64(cos(x) * Float64(cos(eps) + -1.0)) - Float64(sin(eps) * sin(x)));
	else
		tmp = Float64(Float64(cos(x) * Float64(-0.5 * (eps ^ 2.0))) - Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -4.4e-5) || ~((eps <= 3e-5)))
		tmp = (cos(x) * (cos(eps) + -1.0)) - (sin(eps) * sin(x));
	else
		tmp = (cos(x) * (-0.5 * (eps ^ 2.0))) - (eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -4.4e-5], N[Not[LessEqual[eps, 3e-5]], $MachinePrecision]], N[(N[(N[Cos[x], $MachinePrecision] * N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Cos[x], $MachinePrecision] * N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -4.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3 \cdot 10^{-5}\right):\\
\;\;\;\;\cos x \cdot \left(\cos \varepsilon + -1\right) - \sin \varepsilon \cdot \sin x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -4.3999999999999999e-5 or 3.00000000000000008e-5 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg50.7%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. cancel-sign-sub-inv98.5%

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

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

        \[\leadsto \cos x \cdot \cos \varepsilon + \left(\color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} + \left(-\cos x\right)\right) \]
    3. Applied egg-rr98.6%

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

        \[\leadsto \cos x \cdot \cos \varepsilon + \color{blue}{\left(\left(-\cos x\right) + \sin \varepsilon \cdot \left(-\sin x\right)\right)} \]
      2. distribute-rgt-neg-out98.6%

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

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

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

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

        \[\leadsto \left(\color{blue}{\cos \varepsilon \cdot \cos x} + \left(-\cos x\right)\right) - \sin x \cdot \sin \varepsilon \]
      7. neg-mul-198.7%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x + \color{blue}{-1 \cdot \cos x}\right) - \sin x \cdot \sin \varepsilon \]
      8. distribute-rgt-out98.6%

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

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

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

    if -4.3999999999999999e-5 < eps < 3.00000000000000008e-5

    1. Initial program 20.6%

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

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right)} \]
    3. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + -1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      2. mul-1-neg99.7%

        \[\leadsto -0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \color{blue}{\left(-\varepsilon \cdot \sin x\right)} \]
      3. unsub-neg99.7%

        \[\leadsto \color{blue}{-0.5 \cdot \left({\varepsilon}^{2} \cdot \cos x\right) - \varepsilon \cdot \sin x} \]
      4. associate-*r*99.7%

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

        \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right)} - \varepsilon \cdot \sin x \]
    4. Simplified99.7%

      \[\leadsto \color{blue}{\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -4.4 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 3 \cdot 10^{-5}\right):\\ \;\;\;\;\cos x \cdot \left(\cos \varepsilon + -1\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\cos x \cdot \left(-0.5 \cdot {\varepsilon}^{2}\right) - \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 8: 65.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\varepsilon + x\right) - \cos x\\ \mathbf{if}\;t_0 \leq -1 \cdot 10^{-12}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;-\varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (- (cos (+ eps x)) (cos x))))
   (if (<= t_0 -1e-12) t_0 (- (* eps (sin x))))))
double code(double x, double eps) {
	double t_0 = cos((eps + x)) - cos(x);
	double tmp;
	if (t_0 <= -1e-12) {
		tmp = t_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) :: t_0
    real(8) :: tmp
    t_0 = cos((eps + x)) - cos(x)
    if (t_0 <= (-1d-12)) then
        tmp = t_0
    else
        tmp = -(eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.cos((eps + x)) - Math.cos(x);
	double tmp;
	if (t_0 <= -1e-12) {
		tmp = t_0;
	} else {
		tmp = -(eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos((eps + x)) - math.cos(x)
	tmp = 0
	if t_0 <= -1e-12:
		tmp = t_0
	else:
		tmp = -(eps * math.sin(x))
	return tmp
function code(x, eps)
	t_0 = Float64(cos(Float64(eps + x)) - cos(x))
	tmp = 0.0
	if (t_0 <= -1e-12)
		tmp = t_0;
	else
		tmp = Float64(-Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos((eps + x)) - cos(x);
	tmp = 0.0;
	if (t_0 <= -1e-12)
		tmp = t_0;
	else
		tmp = -(eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -1e-12], t$95$0, (-N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision])]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\varepsilon + x\right) - \cos x\\
\mathbf{if}\;t_0 \leq -1 \cdot 10^{-12}:\\
\;\;\;\;t_0\\

\mathbf{else}:\\
\;\;\;\;-\varepsilon \cdot \sin x\\


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

    1. Initial program 75.0%

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

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

    1. Initial program 16.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 62.4%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*62.4%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg62.4%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified62.4%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification66.4%

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

Alternative 9: 68.2% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\varepsilon + x\right) - \cos x\\ \mathbf{if}\;t_0 \leq -1 \cdot 10^{-12}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;\sin \varepsilon \cdot \left(-\sin x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (- (cos (+ eps x)) (cos x))))
   (if (<= t_0 -1e-12) t_0 (* (sin eps) (- (sin x))))))
double code(double x, double eps) {
	double t_0 = cos((eps + x)) - cos(x);
	double tmp;
	if (t_0 <= -1e-12) {
		tmp = t_0;
	} else {
		tmp = sin(eps) * -sin(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: tmp
    t_0 = cos((eps + x)) - cos(x)
    if (t_0 <= (-1d-12)) then
        tmp = t_0
    else
        tmp = sin(eps) * -sin(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.cos((eps + x)) - Math.cos(x);
	double tmp;
	if (t_0 <= -1e-12) {
		tmp = t_0;
	} else {
		tmp = Math.sin(eps) * -Math.sin(x);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos((eps + x)) - math.cos(x)
	tmp = 0
	if t_0 <= -1e-12:
		tmp = t_0
	else:
		tmp = math.sin(eps) * -math.sin(x)
	return tmp
function code(x, eps)
	t_0 = Float64(cos(Float64(eps + x)) - cos(x))
	tmp = 0.0
	if (t_0 <= -1e-12)
		tmp = t_0;
	else
		tmp = Float64(sin(eps) * Float64(-sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos((eps + x)) - cos(x);
	tmp = 0.0;
	if (t_0 <= -1e-12)
		tmp = t_0;
	else
		tmp = sin(eps) * -sin(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[N[(eps + x), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -1e-12], t$95$0, N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\varepsilon + x\right) - \cos x\\
\mathbf{if}\;t_0 \leq -1 \cdot 10^{-12}:\\
\;\;\;\;t_0\\

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


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

    1. Initial program 75.0%

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

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

    1. Initial program 16.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg16.8%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative16.8%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum41.4%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv41.4%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+87.6%

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

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr87.6%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Taylor expanded in x around 0 64.6%

      \[\leadsto \color{blue}{\left(\cos \varepsilon - 1\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Taylor expanded in eps around 0 65.7%

      \[\leadsto \left(\color{blue}{1} - 1\right) + \sin \varepsilon \cdot \left(-\sin x\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification68.7%

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

Alternative 10: 76.4% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.027 \lor \neg \left(\varepsilon \leq 0.0038\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2} - \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.027) (not (<= eps 0.0038)))
   (- (cos eps) (cos x))
   (- (* -0.5 (pow eps 2.0)) (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.027) || !(eps <= 0.0038)) {
		tmp = cos(eps) - cos(x);
	} else {
		tmp = (-0.5 * pow(eps, 2.0)) - (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 <= (-0.027d0)) .or. (.not. (eps <= 0.0038d0))) then
        tmp = cos(eps) - cos(x)
    else
        tmp = ((-0.5d0) * (eps ** 2.0d0)) - (eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.027) || !(eps <= 0.0038)) {
		tmp = Math.cos(eps) - Math.cos(x);
	} else {
		tmp = (-0.5 * Math.pow(eps, 2.0)) - (eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.027) or not (eps <= 0.0038):
		tmp = math.cos(eps) - math.cos(x)
	else:
		tmp = (-0.5 * math.pow(eps, 2.0)) - (eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.027) || !(eps <= 0.0038))
		tmp = Float64(cos(eps) - cos(x));
	else
		tmp = Float64(Float64(-0.5 * (eps ^ 2.0)) - Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.027) || ~((eps <= 0.0038)))
		tmp = cos(eps) - cos(x);
	else
		tmp = (-0.5 * (eps ^ 2.0)) - (eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.027], N[Not[LessEqual[eps, 0.0038]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision] - N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.027 \lor \neg \left(\varepsilon \leq 0.0038\right):\\
\;\;\;\;\cos \varepsilon - \cos x\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot {\varepsilon}^{2} - \varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.0269999999999999997 or 0.00379999999999999999 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 52.5%

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

    if -0.0269999999999999997 < eps < 0.00379999999999999999

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg20.6%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. +-commutative20.6%

        \[\leadsto \color{blue}{\left(-\cos x\right) + \cos \left(x + \varepsilon\right)} \]
      3. cos-sum21.0%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} \]
      4. cancel-sign-sub-inv21.0%

        \[\leadsto \left(-\cos x\right) + \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
      5. associate-+r+83.3%

        \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \left(-\sin x\right) \cdot \sin \varepsilon} \]
      6. *-commutative83.3%

        \[\leadsto \left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \color{blue}{\sin \varepsilon \cdot \left(-\sin x\right)} \]
    3. Applied egg-rr83.3%

      \[\leadsto \color{blue}{\left(\left(-\cos x\right) + \cos x \cdot \cos \varepsilon\right) + \sin \varepsilon \cdot \left(-\sin x\right)} \]
    4. Taylor expanded in x around 0 83.3%

      \[\leadsto \color{blue}{\left(\cos \varepsilon - 1\right)} + \sin \varepsilon \cdot \left(-\sin x\right) \]
    5. Taylor expanded in eps around 0 99.5%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right) + -0.5 \cdot {\varepsilon}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification76.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.027 \lor \neg \left(\varepsilon \leq 0.0038\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2} - \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 11: 67.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -5.4 \cdot 10^{-6} \lor \neg \left(\varepsilon \leq 5.8 \cdot 10^{-6}\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-\varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -5.4e-6) (not (<= eps 5.8e-6)))
   (- (cos eps) (cos x))
   (- (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -5.4e-6) || !(eps <= 5.8e-6)) {
		tmp = cos(eps) - cos(x);
	} 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 <= (-5.4d-6)) .or. (.not. (eps <= 5.8d-6))) then
        tmp = cos(eps) - cos(x)
    else
        tmp = -(eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -5.4e-6) || !(eps <= 5.8e-6)) {
		tmp = Math.cos(eps) - Math.cos(x);
	} else {
		tmp = -(eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -5.4e-6) or not (eps <= 5.8e-6):
		tmp = math.cos(eps) - math.cos(x)
	else:
		tmp = -(eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -5.4e-6) || !(eps <= 5.8e-6))
		tmp = Float64(cos(eps) - cos(x));
	else
		tmp = Float64(-Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -5.4e-6) || ~((eps <= 5.8e-6)))
		tmp = cos(eps) - cos(x);
	else
		tmp = -(eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -5.4e-6], N[Not[LessEqual[eps, 5.8e-6]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], (-N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision])]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -5.4 \cdot 10^{-6} \lor \neg \left(\varepsilon \leq 5.8 \cdot 10^{-6}\right):\\
\;\;\;\;\cos \varepsilon - \cos x\\

\mathbf{else}:\\
\;\;\;\;-\varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -5.39999999999999997e-6 or 5.8000000000000004e-6 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 52.5%

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

    if -5.39999999999999997e-6 < eps < 5.8000000000000004e-6

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 83.2%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*83.2%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg83.2%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified83.2%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -5.4 \cdot 10^{-6} \lor \neg \left(\varepsilon \leq 5.8 \cdot 10^{-6}\right):\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{else}:\\ \;\;\;\;-\varepsilon \cdot \sin x\\ \end{array} \]

Alternative 12: 76.0% accurate, 1.0× speedup?

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

\\
\sin \left(0.5 \cdot \left(\varepsilon + x \cdot 2\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)
\end{array}
Derivation
  1. Initial program 35.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. diff-cos43.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv43.7%

      \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. +-commutative43.7%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} - x\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. associate--l+75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(\varepsilon + \left(x - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    5. *-un-lft-identity75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + \left(x - \color{blue}{1 \cdot x}\right)\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    6. *-un-lft-identity75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + \left(\color{blue}{1 \cdot x} - 1 \cdot x\right)\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    7. distribute-rgt-out--75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + \color{blue}{x \cdot \left(1 - 1\right)}\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    8. metadata-eval75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot \color{blue}{0}\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    9. metadata-eval75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    10. div-inv75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    11. +-commutative75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
    12. associate-+l+75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    13. count-275.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \color{blue}{2 \cdot x}\right) \cdot \frac{1}{2}\right)\right) \]
    14. *-commutative75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \color{blue}{x \cdot 2}\right) \cdot \frac{1}{2}\right)\right) \]
    15. metadata-eval75.8%

      \[\leadsto -2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + x \cdot 2\right) \cdot \color{blue}{0.5}\right)\right) \]
  3. Applied egg-rr75.8%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + x \cdot 2\right) \cdot 0.5\right)\right)} \]
  4. Step-by-step derivation
    1. associate-*r*75.8%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + x \cdot 2\right) \cdot 0.5\right)} \]
    2. *-commutative75.8%

      \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + x \cdot 2\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right)\right)} \]
    3. *-commutative75.8%

      \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + x \cdot 2\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(\varepsilon + x \cdot 0\right) \cdot 0.5\right)\right) \]
    4. *-commutative75.8%

      \[\leadsto \sin \left(0.5 \cdot \left(\varepsilon + x \cdot 2\right)\right) \cdot \left(-2 \cdot \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + x \cdot 0\right)\right)}\right) \]
    5. mul0-rgt75.8%

      \[\leadsto \sin \left(0.5 \cdot \left(\varepsilon + x \cdot 2\right)\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\varepsilon + \color{blue}{0}\right)\right)\right) \]
  5. Simplified75.8%

    \[\leadsto \color{blue}{\sin \left(0.5 \cdot \left(\varepsilon + x \cdot 2\right)\right) \cdot \left(-2 \cdot \sin \left(0.5 \cdot \left(\varepsilon + 0\right)\right)\right)} \]
  6. Final simplification75.8%

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

Alternative 13: 46.6% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.000125 \lor \neg \left(\varepsilon \leq 0.00014\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.000125) (not (<= eps 0.00014)))
   (+ (cos eps) -1.0)
   (* -0.5 (pow eps 2.0))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.000125) || !(eps <= 0.00014)) {
		tmp = cos(eps) + -1.0;
	} else {
		tmp = -0.5 * pow(eps, 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 <= (-0.000125d0)) .or. (.not. (eps <= 0.00014d0))) then
        tmp = cos(eps) + (-1.0d0)
    else
        tmp = (-0.5d0) * (eps ** 2.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.000125) || !(eps <= 0.00014)) {
		tmp = Math.cos(eps) + -1.0;
	} else {
		tmp = -0.5 * Math.pow(eps, 2.0);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.000125) or not (eps <= 0.00014):
		tmp = math.cos(eps) + -1.0
	else:
		tmp = -0.5 * math.pow(eps, 2.0)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.000125) || !(eps <= 0.00014))
		tmp = Float64(cos(eps) + -1.0);
	else
		tmp = Float64(-0.5 * (eps ^ 2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.000125) || ~((eps <= 0.00014)))
		tmp = cos(eps) + -1.0;
	else
		tmp = -0.5 * (eps ^ 2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.000125], N[Not[LessEqual[eps, 0.00014]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.000125 \lor \neg \left(\varepsilon \leq 0.00014\right):\\
\;\;\;\;\cos \varepsilon + -1\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.25e-4 or 1.3999999999999999e-4 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 51.0%

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

    if -1.25e-4 < eps < 1.3999999999999999e-4

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 20.5%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 34.4%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification42.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.000125 \lor \neg \left(\varepsilon \leq 0.00014\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \end{array} \]

Alternative 14: 66.6% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-6}\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-\varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -1.1e-5) (not (<= eps 2.7e-6)))
   (+ (cos eps) -1.0)
   (- (* eps (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.1e-5) || !(eps <= 2.7e-6)) {
		tmp = cos(eps) + -1.0;
	} 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 <= (-1.1d-5)) .or. (.not. (eps <= 2.7d-6))) then
        tmp = cos(eps) + (-1.0d0)
    else
        tmp = -(eps * sin(x))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.1e-5) || !(eps <= 2.7e-6)) {
		tmp = Math.cos(eps) + -1.0;
	} else {
		tmp = -(eps * Math.sin(x));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -1.1e-5) or not (eps <= 2.7e-6):
		tmp = math.cos(eps) + -1.0
	else:
		tmp = -(eps * math.sin(x))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -1.1e-5) || !(eps <= 2.7e-6))
		tmp = Float64(cos(eps) + -1.0);
	else
		tmp = Float64(-Float64(eps * sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -1.1e-5) || ~((eps <= 2.7e-6)))
		tmp = cos(eps) + -1.0;
	else
		tmp = -(eps * sin(x));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -1.1e-5], N[Not[LessEqual[eps, 2.7e-6]], $MachinePrecision]], N[(N[Cos[eps], $MachinePrecision] + -1.0), $MachinePrecision], (-N[(eps * N[Sin[x], $MachinePrecision]), $MachinePrecision])]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -1.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-6}\right):\\
\;\;\;\;\cos \varepsilon + -1\\

\mathbf{else}:\\
\;\;\;\;-\varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.1e-5 or 2.69999999999999998e-6 < eps

    1. Initial program 50.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 51.0%

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

    if -1.1e-5 < eps < 2.69999999999999998e-6

    1. Initial program 20.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 83.2%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. associate-*r*83.2%

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      2. mul-1-neg83.2%

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    4. Simplified83.2%

      \[\leadsto \color{blue}{\left(-\varepsilon\right) \cdot \sin x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.1 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 2.7 \cdot 10^{-6}\right):\\ \;\;\;\;\cos \varepsilon + -1\\ \mathbf{else}:\\ \;\;\;\;-\varepsilon \cdot \sin x\\ \end{array} \]

Alternative 15: 14.5% accurate, 2.0× speedup?

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

\\
1 - \cos \varepsilon
\end{array}
Derivation
  1. Initial program 35.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 35.7%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Step-by-step derivation
    1. add-log-exp35.7%

      \[\leadsto \color{blue}{\log \left(e^{\cos \varepsilon}\right)} - 1 \]
  4. Applied egg-rr35.7%

    \[\leadsto \color{blue}{\log \left(e^{\cos \varepsilon}\right)} - 1 \]
  5. Step-by-step derivation
    1. add-log-exp35.7%

      \[\leadsto \color{blue}{\cos \varepsilon} - 1 \]
    2. flip--35.7%

      \[\leadsto \color{blue}{\frac{\cos \varepsilon \cdot \cos \varepsilon - 1 \cdot 1}{\cos \varepsilon + 1}} \]
    3. metadata-eval35.7%

      \[\leadsto \frac{\cos \varepsilon \cdot \cos \varepsilon - \color{blue}{1}}{\cos \varepsilon + 1} \]
    4. sub-1-cos42.8%

      \[\leadsto \frac{\color{blue}{-\sin \varepsilon \cdot \sin \varepsilon}}{\cos \varepsilon + 1} \]
    5. unpow242.7%

      \[\leadsto \frac{-\color{blue}{{\sin \varepsilon}^{2}}}{\cos \varepsilon + 1} \]
    6. neg-mul-142.7%

      \[\leadsto \frac{\color{blue}{-1 \cdot {\sin \varepsilon}^{2}}}{\cos \varepsilon + 1} \]
    7. *-un-lft-identity42.7%

      \[\leadsto \frac{-1 \cdot {\sin \varepsilon}^{2}}{\color{blue}{1 \cdot \left(\cos \varepsilon + 1\right)}} \]
    8. times-frac42.7%

      \[\leadsto \color{blue}{\frac{-1}{1} \cdot \frac{{\sin \varepsilon}^{2}}{\cos \varepsilon + 1}} \]
    9. metadata-eval42.7%

      \[\leadsto \color{blue}{-1} \cdot \frac{{\sin \varepsilon}^{2}}{\cos \varepsilon + 1} \]
    10. add-sqr-sqrt42.8%

      \[\leadsto -1 \cdot \frac{\color{blue}{\sqrt{{\sin \varepsilon}^{2}} \cdot \sqrt{{\sin \varepsilon}^{2}}}}{\cos \varepsilon + 1} \]
    11. sqrt-unprod39.4%

      \[\leadsto -1 \cdot \frac{\color{blue}{\sqrt{{\sin \varepsilon}^{2} \cdot {\sin \varepsilon}^{2}}}}{\cos \varepsilon + 1} \]
    12. sqr-neg39.4%

      \[\leadsto -1 \cdot \frac{\sqrt{\color{blue}{\left(-{\sin \varepsilon}^{2}\right) \cdot \left(-{\sin \varepsilon}^{2}\right)}}}{\cos \varepsilon + 1} \]
    13. sqrt-unprod8.6%

      \[\leadsto -1 \cdot \frac{\color{blue}{\sqrt{-{\sin \varepsilon}^{2}} \cdot \sqrt{-{\sin \varepsilon}^{2}}}}{\cos \varepsilon + 1} \]
    14. add-sqr-sqrt13.3%

      \[\leadsto -1 \cdot \frac{\color{blue}{-{\sin \varepsilon}^{2}}}{\cos \varepsilon + 1} \]
    15. unpow213.3%

      \[\leadsto -1 \cdot \frac{-\color{blue}{\sin \varepsilon \cdot \sin \varepsilon}}{\cos \varepsilon + 1} \]
    16. sub-1-cos13.4%

      \[\leadsto -1 \cdot \frac{\color{blue}{\cos \varepsilon \cdot \cos \varepsilon - 1}}{\cos \varepsilon + 1} \]
    17. metadata-eval13.4%

      \[\leadsto -1 \cdot \frac{\cos \varepsilon \cdot \cos \varepsilon - \color{blue}{1 \cdot 1}}{\cos \varepsilon + 1} \]
    18. flip--13.4%

      \[\leadsto -1 \cdot \color{blue}{\left(\cos \varepsilon - 1\right)} \]
    19. sub-neg13.4%

      \[\leadsto -1 \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} \]
    20. metadata-eval13.4%

      \[\leadsto -1 \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) \]
  6. Applied egg-rr13.4%

    \[\leadsto \color{blue}{-1 \cdot \left(\cos \varepsilon + -1\right)} \]
  7. Step-by-step derivation
    1. +-commutative13.4%

      \[\leadsto -1 \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} \]
    2. distribute-lft-in13.4%

      \[\leadsto \color{blue}{-1 \cdot -1 + -1 \cdot \cos \varepsilon} \]
    3. metadata-eval13.4%

      \[\leadsto \color{blue}{1} + -1 \cdot \cos \varepsilon \]
    4. neg-mul-113.4%

      \[\leadsto 1 + \color{blue}{\left(-\cos \varepsilon\right)} \]
    5. sub-neg13.4%

      \[\leadsto \color{blue}{1 - \cos \varepsilon} \]
  8. Simplified13.4%

    \[\leadsto \color{blue}{1 - \cos \varepsilon} \]
  9. Final simplification13.4%

    \[\leadsto 1 - \cos \varepsilon \]

Alternative 16: 38.1% accurate, 2.0× speedup?

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

\\
\cos \varepsilon + -1
\end{array}
Derivation
  1. Initial program 35.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 35.7%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Final simplification35.7%

    \[\leadsto \cos \varepsilon + -1 \]

Alternative 17: 12.9% 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 35.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. diff-cos43.7%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. sin-mult35.5%

      \[\leadsto -2 \cdot \color{blue}{\frac{\cos \left(\frac{\left(x + \varepsilon\right) - x}{2} - \frac{\left(x + \varepsilon\right) + x}{2}\right) - \cos \left(\frac{\left(x + \varepsilon\right) - x}{2} + \frac{\left(x + \varepsilon\right) + x}{2}\right)}{2}} \]
    3. associate-*r/35.5%

      \[\leadsto \color{blue}{\frac{-2 \cdot \left(\cos \left(\frac{\left(x + \varepsilon\right) - x}{2} - \frac{\left(x + \varepsilon\right) + x}{2}\right) - \cos \left(\frac{\left(x + \varepsilon\right) - x}{2} + \frac{\left(x + \varepsilon\right) + x}{2}\right)\right)}{2}} \]
  3. Applied egg-rr35.7%

    \[\leadsto \color{blue}{\frac{-2 \cdot \left(\cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) - \left(\varepsilon + x \cdot 2\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)\right)}{2}} \]
  4. Step-by-step derivation
    1. *-commutative35.7%

      \[\leadsto \frac{\color{blue}{\left(\cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) - \left(\varepsilon + x \cdot 2\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)\right) \cdot -2}}{2} \]
    2. associate-/l*35.7%

      \[\leadsto \color{blue}{\frac{\cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) - \left(\varepsilon + x \cdot 2\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{\frac{2}{-2}}} \]
    3. associate--l+35.7%

      \[\leadsto \frac{\cos \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x \cdot 0 - \left(\varepsilon + x \cdot 2\right)\right)\right)}\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{\frac{2}{-2}} \]
    4. mul0-rgt35.7%

      \[\leadsto \frac{\cos \left(0.5 \cdot \left(\varepsilon + \left(\color{blue}{0} - \left(\varepsilon + x \cdot 2\right)\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + x \cdot 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{\frac{2}{-2}} \]
    5. mul0-rgt35.7%

      \[\leadsto \frac{\cos \left(0.5 \cdot \left(\varepsilon + \left(0 - \left(\varepsilon + x \cdot 2\right)\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + \color{blue}{0}\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{\frac{2}{-2}} \]
    6. metadata-eval35.7%

      \[\leadsto \frac{\cos \left(0.5 \cdot \left(\varepsilon + \left(0 - \left(\varepsilon + x \cdot 2\right)\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{\color{blue}{-1}} \]
  5. Simplified35.7%

    \[\leadsto \color{blue}{\frac{\cos \left(0.5 \cdot \left(\varepsilon + \left(0 - \left(\varepsilon + x \cdot 2\right)\right)\right)\right) - \cos \left(0.5 \cdot \left(\left(\varepsilon + 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)}{-1}} \]
  6. Step-by-step derivation
    1. sub-neg35.7%

      \[\leadsto \frac{\color{blue}{\cos \left(0.5 \cdot \left(\varepsilon + \left(0 - \left(\varepsilon + x \cdot 2\right)\right)\right)\right) + \left(-\cos \left(0.5 \cdot \left(\left(\varepsilon + 0\right) + \left(\varepsilon + x \cdot 2\right)\right)\right)\right)}}{-1} \]
  7. Applied egg-rr11.7%

    \[\leadsto \frac{\color{blue}{\cos \left(0.5 \cdot \left(x \cdot 2 + \varepsilon \cdot 2\right)\right) + \left(-\cos \left(0.5 \cdot \left(x \cdot 2 + \varepsilon \cdot 2\right)\right)\right)}}{-1} \]
  8. Step-by-step derivation
    1. sub-neg11.7%

      \[\leadsto \frac{\color{blue}{\cos \left(0.5 \cdot \left(x \cdot 2 + \varepsilon \cdot 2\right)\right) - \cos \left(0.5 \cdot \left(x \cdot 2 + \varepsilon \cdot 2\right)\right)}}{-1} \]
    2. +-inverses11.7%

      \[\leadsto \frac{\color{blue}{0}}{-1} \]
  9. Simplified11.7%

    \[\leadsto \frac{\color{blue}{0}}{-1} \]
  10. Final simplification11.7%

    \[\leadsto 0 \]

Reproduce

?
herbie shell --seed 2023336 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))