2cos (problem 3.3.5)

Percentage Accurate: 52.5% → 99.7%
Time: 16.6s
Alternatives: 9
Speedup: 25.9×

Specification

?
\[\left(\left(-10000 \leq x \land x \leq 10000\right) \land 10^{-16} \cdot \left|x\right| < \varepsilon\right) \land \varepsilon < \left|x\right|\]
\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

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

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 9 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: 52.5% 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: 99.7% accurate, 0.9× speedup?

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

\\
-2 \cdot \left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right)
\end{array}
Derivation
  1. Initial program 51.2%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. lift-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    3. lift-cos.f64N/A

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{\cos x} \]
    4. diff-cosN/A

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    6. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
  4. Applied rewrites99.7%

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

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

Alternative 2: 99.5% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \left(\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-1.5500992063492063 \cdot 10^{-6} \cdot \varepsilon, \varepsilon, 0.00026041666666666666\right) \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2 \end{array} \]
(FPCore (x eps)
 :precision binary64
 (*
  (*
   (*
    (fma
     (*
      (fma
       (* (fma (* -1.5500992063492063e-6 eps) eps 0.00026041666666666666) eps)
       eps
       -0.020833333333333332)
      eps)
     eps
     0.5)
    eps)
   (sin (* (fma 2.0 x eps) 0.5)))
  -2.0))
double code(double x, double eps) {
	return ((fma((fma((fma((-1.5500992063492063e-6 * eps), eps, 0.00026041666666666666) * eps), eps, -0.020833333333333332) * eps), eps, 0.5) * eps) * sin((fma(2.0, x, eps) * 0.5))) * -2.0;
}
function code(x, eps)
	return Float64(Float64(Float64(fma(Float64(fma(Float64(fma(Float64(-1.5500992063492063e-6 * eps), eps, 0.00026041666666666666) * eps), eps, -0.020833333333333332) * eps), eps, 0.5) * eps) * sin(Float64(fma(2.0, x, eps) * 0.5))) * -2.0)
end
code[x_, eps_] := N[(N[(N[(N[(N[(N[(N[(N[(N[(-1.5500992063492063e-6 * eps), $MachinePrecision] * eps + 0.00026041666666666666), $MachinePrecision] * eps), $MachinePrecision] * eps + -0.020833333333333332), $MachinePrecision] * eps), $MachinePrecision] * eps + 0.5), $MachinePrecision] * eps), $MachinePrecision] * N[Sin[N[(N[(2.0 * x + eps), $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-1.5500992063492063 \cdot 10^{-6} \cdot \varepsilon, \varepsilon, 0.00026041666666666666\right) \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 51.2%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. lift-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    3. lift-cos.f64N/A

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{\cos x} \]
    4. diff-cosN/A

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    6. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
  4. Applied rewrites99.7%

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

    \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\varepsilon \cdot \left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left({\varepsilon}^{2} \cdot \left(\frac{1}{3840} + \frac{-1}{645120} \cdot {\varepsilon}^{2}\right) - \frac{1}{48}\right)\right)\right)}\right) \cdot -2 \]
  6. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left({\varepsilon}^{2} \cdot \left(\frac{1}{3840} + \frac{-1}{645120} \cdot {\varepsilon}^{2}\right) - \frac{1}{48}\right)\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    2. lower-*.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left({\varepsilon}^{2} \cdot \left(\frac{1}{3840} + \frac{-1}{645120} \cdot {\varepsilon}^{2}\right) - \frac{1}{48}\right)\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
  7. Applied rewrites99.5%

    \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-1.5500992063492063 \cdot 10^{-6} \cdot \varepsilon, \varepsilon, 0.00026041666666666666\right) \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
  8. Final simplification99.5%

    \[\leadsto \left(\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-1.5500992063492063 \cdot 10^{-6} \cdot \varepsilon, \varepsilon, 0.00026041666666666666\right) \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2 \]
  9. Add Preprocessing

Alternative 3: 99.5% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \left(\left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right)\right) \cdot -2 \end{array} \]
(FPCore (x eps)
 :precision binary64
 (*
  (*
   (*
    (fma
     (* (fma (* 0.00026041666666666666 eps) eps -0.020833333333333332) eps)
     eps
     0.5)
    eps)
   (sin (fma eps 0.5 x)))
  -2.0))
double code(double x, double eps) {
	return ((fma((fma((0.00026041666666666666 * eps), eps, -0.020833333333333332) * eps), eps, 0.5) * eps) * sin(fma(eps, 0.5, x))) * -2.0;
}
function code(x, eps)
	return Float64(Float64(Float64(fma(Float64(fma(Float64(0.00026041666666666666 * eps), eps, -0.020833333333333332) * eps), eps, 0.5) * eps) * sin(fma(eps, 0.5, x))) * -2.0)
end
code[x_, eps_] := N[(N[(N[(N[(N[(N[(N[(0.00026041666666666666 * eps), $MachinePrecision] * eps + -0.020833333333333332), $MachinePrecision] * eps), $MachinePrecision] * eps + 0.5), $MachinePrecision] * eps), $MachinePrecision] * N[Sin[N[(eps * 0.5 + x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 51.2%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. lift-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    3. lift-cos.f64N/A

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{\cos x} \]
    4. diff-cosN/A

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    6. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
  4. Applied rewrites99.7%

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

    \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\varepsilon \cdot \left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right)\right)\right)}\right) \cdot -2 \]
  6. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right)\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    2. lower-*.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + {\varepsilon}^{2} \cdot \left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right)\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    3. +-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\color{blue}{\left({\varepsilon}^{2} \cdot \left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) + \frac{1}{2}\right)} \cdot \varepsilon\right)\right) \cdot -2 \]
    4. *-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\left(\color{blue}{\left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) \cdot {\varepsilon}^{2}} + \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    5. unpow2N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\left(\left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    6. associate-*r*N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\left(\color{blue}{\left(\left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) \cdot \varepsilon\right) \cdot \varepsilon} + \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    7. lower-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\color{blue}{\mathsf{fma}\left(\left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right)} \cdot \varepsilon\right)\right) \cdot -2 \]
    8. lower-*.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\color{blue}{\left(\frac{1}{3840} \cdot {\varepsilon}^{2} - \frac{1}{48}\right) \cdot \varepsilon}, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    9. sub-negN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\color{blue}{\left(\frac{1}{3840} \cdot {\varepsilon}^{2} + \left(\mathsf{neg}\left(\frac{1}{48}\right)\right)\right)} \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    10. unpow2N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\left(\frac{1}{3840} \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + \left(\mathsf{neg}\left(\frac{1}{48}\right)\right)\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    11. associate-*r*N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\left(\color{blue}{\left(\frac{1}{3840} \cdot \varepsilon\right) \cdot \varepsilon} + \left(\mathsf{neg}\left(\frac{1}{48}\right)\right)\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    12. metadata-evalN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\left(\left(\frac{1}{3840} \cdot \varepsilon\right) \cdot \varepsilon + \color{blue}{\frac{-1}{48}}\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    13. lower-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{3840} \cdot \varepsilon, \varepsilon, \frac{-1}{48}\right)} \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    14. lower-*.f6499.5

      \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{0.00026041666666666666 \cdot \varepsilon}, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \]
  7. Applied rewrites99.5%

    \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
  8. Taylor expanded in x around 0

    \[\leadsto \left(\sin \color{blue}{\left(x + \frac{1}{2} \cdot \varepsilon\right)} \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{3840} \cdot \varepsilon, \varepsilon, \frac{-1}{48}\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
  9. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \left(\sin \color{blue}{\left(\frac{1}{2} \cdot \varepsilon + x\right)} \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{3840} \cdot \varepsilon, \varepsilon, \frac{-1}{48}\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    2. *-commutativeN/A

      \[\leadsto \left(\sin \left(\color{blue}{\varepsilon \cdot \frac{1}{2}} + x\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{3840} \cdot \varepsilon, \varepsilon, \frac{-1}{48}\right) \cdot \varepsilon, \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    3. lower-fma.f6499.5

      \[\leadsto \left(\sin \color{blue}{\left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right)} \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \]
  10. Applied rewrites99.5%

    \[\leadsto \left(\sin \color{blue}{\left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right)} \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \]
  11. Final simplification99.5%

    \[\leadsto \left(\left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666 \cdot \varepsilon, \varepsilon, -0.020833333333333332\right) \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right)\right) \cdot -2 \]
  12. Add Preprocessing

Alternative 4: 99.4% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \left(\left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2 \end{array} \]
(FPCore (x eps)
 :precision binary64
 (*
  (*
   (* (fma (* -0.020833333333333332 eps) eps 0.5) eps)
   (sin (* (fma 2.0 x eps) 0.5)))
  -2.0))
double code(double x, double eps) {
	return ((fma((-0.020833333333333332 * eps), eps, 0.5) * eps) * sin((fma(2.0, x, eps) * 0.5))) * -2.0;
}
function code(x, eps)
	return Float64(Float64(Float64(fma(Float64(-0.020833333333333332 * eps), eps, 0.5) * eps) * sin(Float64(fma(2.0, x, eps) * 0.5))) * -2.0)
end
code[x_, eps_] := N[(N[(N[(N[(N[(-0.020833333333333332 * eps), $MachinePrecision] * eps + 0.5), $MachinePrecision] * eps), $MachinePrecision] * N[Sin[N[(N[(2.0 * x + eps), $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 51.2%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. lift-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    3. lift-cos.f64N/A

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{\cos x} \]
    4. diff-cosN/A

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    6. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
  4. Applied rewrites99.7%

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

    \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\varepsilon \cdot \left(\frac{1}{2} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right)\right)}\right) \cdot -2 \]
  6. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    2. lower-*.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\left(\frac{1}{2} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    3. +-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\color{blue}{\left(\frac{-1}{48} \cdot {\varepsilon}^{2} + \frac{1}{2}\right)} \cdot \varepsilon\right)\right) \cdot -2 \]
    4. unpow2N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\left(\frac{-1}{48} \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    5. associate-*r*N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\left(\color{blue}{\left(\frac{-1}{48} \cdot \varepsilon\right) \cdot \varepsilon} + \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
    6. lower-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\color{blue}{\mathsf{fma}\left(\frac{-1}{48} \cdot \varepsilon, \varepsilon, \frac{1}{2}\right)} \cdot \varepsilon\right)\right) \cdot -2 \]
    7. lower-*.f6499.4

      \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\color{blue}{-0.020833333333333332 \cdot \varepsilon}, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \]
  7. Applied rewrites99.4%

    \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
  8. Final simplification99.4%

    \[\leadsto \left(\left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2 \]
  9. Add Preprocessing

Alternative 5: 99.2% accurate, 1.6× speedup?

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

\\
\left(\left(\varepsilon \cdot 0.5\right) \cdot \sin \left(\mathsf{fma}\left(2, x, \varepsilon\right) \cdot 0.5\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 51.2%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) - \cos x} \]
    2. lift-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right)} - \cos x \]
    3. lift-cos.f64N/A

      \[\leadsto \cos \left(x + \varepsilon\right) - \color{blue}{\cos x} \]
    4. diff-cosN/A

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    5. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    6. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
  4. Applied rewrites99.7%

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

    \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\frac{1}{2} \cdot \varepsilon\right)}\right) \cdot -2 \]
  6. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\varepsilon \cdot \frac{1}{2}\right)}\right) \cdot -2 \]
    2. lower-*.f6499.2

      \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\varepsilon \cdot 0.5\right)}\right) \cdot -2 \]
  7. Applied rewrites99.2%

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

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

Alternative 6: 97.7% accurate, 8.3× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666 \cdot x, \varepsilon, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* (fma (fma (* 0.16666666666666666 x) eps -0.5) eps (- x)) eps))
double code(double x, double eps) {
	return fma(fma((0.16666666666666666 * x), eps, -0.5), eps, -x) * eps;
}
function code(x, eps)
	return Float64(fma(fma(Float64(0.16666666666666666 * x), eps, -0.5), eps, Float64(-x)) * eps)
end
code[x_, eps_] := N[(N[(N[(N[(0.16666666666666666 * x), $MachinePrecision] * eps + -0.5), $MachinePrecision] * eps + (-x)), $MachinePrecision] * eps), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666 \cdot x, \varepsilon, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon
\end{array}
Derivation
  1. Initial program 51.2%

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

    \[\leadsto \color{blue}{\left(\cos \varepsilon + -1 \cdot \left(x \cdot \sin \varepsilon\right)\right) - 1} \]
  4. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto \left(\cos \varepsilon + \color{blue}{\left(\mathsf{neg}\left(x \cdot \sin \varepsilon\right)\right)}\right) - 1 \]
    2. unsub-negN/A

      \[\leadsto \color{blue}{\left(\cos \varepsilon - x \cdot \sin \varepsilon\right)} - 1 \]
    3. associate--l-N/A

      \[\leadsto \color{blue}{\cos \varepsilon - \left(x \cdot \sin \varepsilon + 1\right)} \]
    4. lower--.f64N/A

      \[\leadsto \color{blue}{\cos \varepsilon - \left(x \cdot \sin \varepsilon + 1\right)} \]
    5. lower-cos.f64N/A

      \[\leadsto \color{blue}{\cos \varepsilon} - \left(x \cdot \sin \varepsilon + 1\right) \]
    6. *-commutativeN/A

      \[\leadsto \cos \varepsilon - \left(\color{blue}{\sin \varepsilon \cdot x} + 1\right) \]
    7. lower-fma.f64N/A

      \[\leadsto \cos \varepsilon - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, x, 1\right)} \]
    8. lower-sin.f6450.4

      \[\leadsto \cos \varepsilon - \mathsf{fma}\left(\color{blue}{\sin \varepsilon}, x, 1\right) \]
  5. Applied rewrites50.4%

    \[\leadsto \color{blue}{\cos \varepsilon - \mathsf{fma}\left(\sin \varepsilon, x, 1\right)} \]
  6. Taylor expanded in eps around 0

    \[\leadsto \varepsilon \cdot \color{blue}{\left(\varepsilon \cdot \left(\frac{1}{6} \cdot \left(\varepsilon \cdot x\right) - \frac{1}{2}\right) - x\right)} \]
  7. Step-by-step derivation
    1. Applied rewrites97.3%

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666 \cdot x, \varepsilon, -0.5\right), \varepsilon, -x\right) \cdot \color{blue}{\varepsilon} \]
    2. Add Preprocessing

    Alternative 7: 97.7% accurate, 14.8× speedup?

    \[\begin{array}{l} \\ \mathsf{fma}\left(-0.5, \varepsilon, -x\right) \cdot \varepsilon \end{array} \]
    (FPCore (x eps) :precision binary64 (* (fma -0.5 eps (- x)) eps))
    double code(double x, double eps) {
    	return fma(-0.5, eps, -x) * eps;
    }
    
    function code(x, eps)
    	return Float64(fma(-0.5, eps, Float64(-x)) * eps)
    end
    
    code[x_, eps_] := N[(N[(-0.5 * eps + (-x)), $MachinePrecision] * eps), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \mathsf{fma}\left(-0.5, \varepsilon, -x\right) \cdot \varepsilon
    \end{array}
    
    Derivation
    1. Initial program 51.2%

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

      \[\leadsto \color{blue}{\left(\cos \varepsilon + -1 \cdot \left(x \cdot \sin \varepsilon\right)\right) - 1} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \left(\cos \varepsilon + \color{blue}{\left(\mathsf{neg}\left(x \cdot \sin \varepsilon\right)\right)}\right) - 1 \]
      2. unsub-negN/A

        \[\leadsto \color{blue}{\left(\cos \varepsilon - x \cdot \sin \varepsilon\right)} - 1 \]
      3. associate--l-N/A

        \[\leadsto \color{blue}{\cos \varepsilon - \left(x \cdot \sin \varepsilon + 1\right)} \]
      4. lower--.f64N/A

        \[\leadsto \color{blue}{\cos \varepsilon - \left(x \cdot \sin \varepsilon + 1\right)} \]
      5. lower-cos.f64N/A

        \[\leadsto \color{blue}{\cos \varepsilon} - \left(x \cdot \sin \varepsilon + 1\right) \]
      6. *-commutativeN/A

        \[\leadsto \cos \varepsilon - \left(\color{blue}{\sin \varepsilon \cdot x} + 1\right) \]
      7. lower-fma.f64N/A

        \[\leadsto \cos \varepsilon - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, x, 1\right)} \]
      8. lower-sin.f6450.4

        \[\leadsto \cos \varepsilon - \mathsf{fma}\left(\color{blue}{\sin \varepsilon}, x, 1\right) \]
    5. Applied rewrites50.4%

      \[\leadsto \color{blue}{\cos \varepsilon - \mathsf{fma}\left(\sin \varepsilon, x, 1\right)} \]
    6. Taylor expanded in eps around 0

      \[\leadsto \varepsilon \cdot \color{blue}{\left(\frac{-1}{2} \cdot \varepsilon - x\right)} \]
    7. Step-by-step derivation
      1. Applied rewrites97.3%

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

      Alternative 8: 78.9% accurate, 25.9× speedup?

      \[\begin{array}{l} \\ \left(-x\right) \cdot \varepsilon \end{array} \]
      (FPCore (x eps) :precision binary64 (* (- x) eps))
      double code(double x, double eps) {
      	return -x * eps;
      }
      
      real(8) function code(x, eps)
          real(8), intent (in) :: x
          real(8), intent (in) :: eps
          code = -x * eps
      end function
      
      public static double code(double x, double eps) {
      	return -x * eps;
      }
      
      def code(x, eps):
      	return -x * eps
      
      function code(x, eps)
      	return Float64(Float64(-x) * eps)
      end
      
      function tmp = code(x, eps)
      	tmp = -x * eps;
      end
      
      code[x_, eps_] := N[((-x) * eps), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \left(-x\right) \cdot \varepsilon
      \end{array}
      
      Derivation
      1. Initial program 51.2%

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

        \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
      4. Step-by-step derivation
        1. mul-1-negN/A

          \[\leadsto \color{blue}{\mathsf{neg}\left(\varepsilon \cdot \sin x\right)} \]
        2. *-commutativeN/A

          \[\leadsto \mathsf{neg}\left(\color{blue}{\sin x \cdot \varepsilon}\right) \]
        3. distribute-lft-neg-inN/A

          \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\sin x\right)\right) \cdot \varepsilon} \]
        4. lower-*.f64N/A

          \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\sin x\right)\right) \cdot \varepsilon} \]
        5. lower-neg.f64N/A

          \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\sin x\right)\right)} \cdot \varepsilon \]
        6. lower-sin.f6478.5

          \[\leadsto \left(-\color{blue}{\sin x}\right) \cdot \varepsilon \]
      5. Applied rewrites78.5%

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

        \[\leadsto \left(-1 \cdot x\right) \cdot \varepsilon \]
      7. Step-by-step derivation
        1. Applied rewrites77.6%

          \[\leadsto \left(-x\right) \cdot \varepsilon \]
        2. Add Preprocessing

        Alternative 9: 51.1% accurate, 51.8× speedup?

        \[\begin{array}{l} \\ 1 - 1 \end{array} \]
        (FPCore (x eps) :precision binary64 (- 1.0 1.0))
        double code(double x, double eps) {
        	return 1.0 - 1.0;
        }
        
        real(8) function code(x, eps)
            real(8), intent (in) :: x
            real(8), intent (in) :: eps
            code = 1.0d0 - 1.0d0
        end function
        
        public static double code(double x, double eps) {
        	return 1.0 - 1.0;
        }
        
        def code(x, eps):
        	return 1.0 - 1.0
        
        function code(x, eps)
        	return Float64(1.0 - 1.0)
        end
        
        function tmp = code(x, eps)
        	tmp = 1.0 - 1.0;
        end
        
        code[x_, eps_] := N[(1.0 - 1.0), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        1 - 1
        \end{array}
        
        Derivation
        1. Initial program 51.2%

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

          \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
        4. Step-by-step derivation
          1. lower--.f64N/A

            \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
          2. lower-cos.f6449.7

            \[\leadsto \color{blue}{\cos \varepsilon} - 1 \]
        5. Applied rewrites49.7%

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

          \[\leadsto 1 - 1 \]
        7. Step-by-step derivation
          1. Applied rewrites49.5%

            \[\leadsto 1 - 1 \]
          2. Add Preprocessing

          Developer Target 1: 99.7% accurate, 0.9× speedup?

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

          Developer Target 2: 98.7% accurate, 0.5× speedup?

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

          Reproduce

          ?
          herbie shell --seed 2024234 
          (FPCore (x eps)
            :name "2cos (problem 3.3.5)"
            :precision binary64
            :pre (and (and (and (<= -10000.0 x) (<= x 10000.0)) (< (* 1e-16 (fabs x)) eps)) (< eps (fabs x)))
          
            :alt
            (! :herbie-platform default (* -2 (sin (+ x (/ eps 2))) (sin (/ eps 2))))
          
            :alt
            (! :herbie-platform default (pow (cbrt (* -2 (sin (* 1/2 (fma 2 x eps))) (sin (* 1/2 eps)))) 3))
          
            (- (cos (+ x eps)) (cos x)))