2cos (problem 3.3.5)

Percentage Accurate: 51.4% → 100.0%
Time: 16.4s
Alternatives: 8
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 8 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: 51.4% 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: 100.0% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\ -2 \cdot \mathsf{fma}\left(\cos \left(\varepsilon \cdot 0.5\right) \cdot \sin x, t\_0, \left(\cos x \cdot t\_0\right) \cdot t\_0\right) \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (sin (* eps 0.5))))
   (* -2.0 (fma (* (cos (* eps 0.5)) (sin x)) t_0 (* (* (cos x) t_0) t_0)))))
double code(double x, double eps) {
	double t_0 = sin((eps * 0.5));
	return -2.0 * fma((cos((eps * 0.5)) * sin(x)), t_0, ((cos(x) * t_0) * t_0));
}
function code(x, eps)
	t_0 = sin(Float64(eps * 0.5))
	return Float64(-2.0 * fma(Float64(cos(Float64(eps * 0.5)) * sin(x)), t_0, Float64(Float64(cos(x) * t_0) * t_0)))
end
code[x_, eps_] := Block[{t$95$0 = N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]}, N[(-2.0 * N[(N[(N[Cos[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision] * t$95$0 + N[(N[(N[Cos[x], $MachinePrecision] * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\
-2 \cdot \mathsf{fma}\left(\cos \left(\varepsilon \cdot 0.5\right) \cdot \sin x, t\_0, \left(\cos x \cdot t\_0\right) \cdot t\_0\right)
\end{array}
\end{array}
Derivation
  1. Initial program 54.7%

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

      \[\leadsto \left(\color{blue}{\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    2. lift-*.f64N/A

      \[\leadsto \left(\sin \color{blue}{\left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    3. lift-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(2 \cdot x + \varepsilon\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    4. +-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(\varepsilon + 2 \cdot x\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    5. distribute-rgt-inN/A

      \[\leadsto \left(\sin \color{blue}{\left(\varepsilon \cdot \frac{1}{2} + \left(2 \cdot x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    6. *-commutativeN/A

      \[\leadsto \left(\sin \left(\color{blue}{\frac{1}{2} \cdot \varepsilon} + \left(2 \cdot x\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    7. sin-sumN/A

      \[\leadsto \left(\color{blue}{\left(\sin \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    8. +-lft-identityN/A

      \[\leadsto \left(\left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(0 + \varepsilon\right)}\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    9. lift-+.f64N/A

      \[\leadsto \left(\left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(0 + \varepsilon\right)}\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    10. lift-*.f64N/A

      \[\leadsto \left(\left(\sin \color{blue}{\left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)} \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    11. lift-sin.f64N/A

      \[\leadsto \left(\left(\color{blue}{\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)} \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    12. lower-fma.f64N/A

      \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right), \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right), \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  6. Applied rewrites99.7%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(\varepsilon \cdot 0.5\right), \cos \left(1 \cdot x\right), \cos \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(1 \cdot x\right)\right)} \cdot \sin \left(0.5 \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  7. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\sin \left(\varepsilon \cdot \frac{1}{2}\right), \cos \left(1 \cdot x\right), \cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right)} \cdot -2 \]
    2. *-commutativeN/A

      \[\leadsto \color{blue}{\left(\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right) \cdot \mathsf{fma}\left(\sin \left(\varepsilon \cdot \frac{1}{2}\right), \cos \left(1 \cdot x\right), \cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right)\right)\right)} \cdot -2 \]
    3. lift-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right) \cdot \color{blue}{\left(\sin \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \cos \left(1 \cdot x\right) + \cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right)\right)}\right) \cdot -2 \]
    4. +-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right) \cdot \color{blue}{\left(\cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right) + \sin \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \cos \left(1 \cdot x\right)\right)}\right) \cdot -2 \]
    5. distribute-rgt-inN/A

      \[\leadsto \color{blue}{\left(\left(\cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right) + \left(\sin \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \cos \left(1 \cdot x\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right)} \cdot -2 \]
    6. lower-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \sin \left(1 \cdot x\right), \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right), \left(\sin \left(\varepsilon \cdot \frac{1}{2}\right) \cdot \cos \left(1 \cdot x\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right)} \cdot -2 \]
  8. Applied rewrites100.0%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x \cdot \cos \left(0.5 \cdot \varepsilon\right), \sin \left(0.5 \cdot \varepsilon\right), \left(\cos x \cdot \sin \left(0.5 \cdot \varepsilon\right)\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)} \cdot -2 \]
  9. Final simplification100.0%

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

Alternative 2: 99.8% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\ \left(\mathsf{fma}\left(\cos \left(-0.5 \cdot \varepsilon\right), \sin x, \cos x \cdot t\_0\right) \cdot t\_0\right) \cdot -2 \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (sin (* eps 0.5))))
   (* (* (fma (cos (* -0.5 eps)) (sin x) (* (cos x) t_0)) t_0) -2.0)))
double code(double x, double eps) {
	double t_0 = sin((eps * 0.5));
	return (fma(cos((-0.5 * eps)), sin(x), (cos(x) * t_0)) * t_0) * -2.0;
}
function code(x, eps)
	t_0 = sin(Float64(eps * 0.5))
	return Float64(Float64(fma(cos(Float64(-0.5 * eps)), sin(x), Float64(cos(x) * t_0)) * t_0) * -2.0)
end
code[x_, eps_] := Block[{t$95$0 = N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]}, N[(N[(N[(N[Cos[N[(-0.5 * eps), $MachinePrecision]], $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] * t$95$0), $MachinePrecision] * -2.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sin \left(\varepsilon \cdot 0.5\right)\\
\left(\mathsf{fma}\left(\cos \left(-0.5 \cdot \varepsilon\right), \sin x, \cos x \cdot t\_0\right) \cdot t\_0\right) \cdot -2
\end{array}
\end{array}
Derivation
  1. Initial program 54.7%

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

      \[\leadsto \left(\color{blue}{\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    2. lift-*.f64N/A

      \[\leadsto \left(\sin \color{blue}{\left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    3. lift-fma.f64N/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(2 \cdot x + \varepsilon\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    4. +-commutativeN/A

      \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(\varepsilon + 2 \cdot x\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    5. distribute-rgt-inN/A

      \[\leadsto \left(\sin \color{blue}{\left(\varepsilon \cdot \frac{1}{2} + \left(2 \cdot x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    6. *-commutativeN/A

      \[\leadsto \left(\sin \left(\color{blue}{\frac{1}{2} \cdot \varepsilon} + \left(2 \cdot x\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    7. sin-sumN/A

      \[\leadsto \left(\color{blue}{\left(\sin \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    8. +-lft-identityN/A

      \[\leadsto \left(\left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(0 + \varepsilon\right)}\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    9. lift-+.f64N/A

      \[\leadsto \left(\left(\sin \left(\frac{1}{2} \cdot \color{blue}{\left(0 + \varepsilon\right)}\right) \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    10. lift-*.f64N/A

      \[\leadsto \left(\left(\sin \color{blue}{\left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)} \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    11. lift-sin.f64N/A

      \[\leadsto \left(\left(\color{blue}{\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)} \cdot \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) + \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
    12. lower-fma.f64N/A

      \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right), \cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right), \cos \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right)\right)} \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  6. Applied rewrites99.7%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(\varepsilon \cdot 0.5\right), \cos \left(1 \cdot x\right), \cos \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(1 \cdot x\right)\right)} \cdot \sin \left(0.5 \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  7. Taylor expanded in eps around inf

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

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

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(\cos \color{blue}{\left(\frac{-1}{2} \cdot \left(-1 \cdot \varepsilon\right)\right)}, \sin x, \cos x \cdot \sin \left(\frac{1}{2} \cdot \varepsilon\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \varepsilon\right)\right) \cdot -2 \]
    7. mul-1-negN/A

      \[\leadsto \left(\mathsf{fma}\left(\cos \left(\frac{-1}{2} \cdot \color{blue}{\left(\mathsf{neg}\left(\varepsilon\right)\right)}\right), \sin x, \cos x \cdot \sin \left(\frac{1}{2} \cdot \varepsilon\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \varepsilon\right)\right) \cdot -2 \]
    8. distribute-rgt-neg-outN/A

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Alternative 3: 99.7% accurate, 0.9× speedup?

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

\\
\left(\sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right) \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 54.7%

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

    \[\leadsto \color{blue}{\left(\sin \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \sin \left(\frac{1}{2} \cdot \left(\varepsilon + 2 \cdot x\right)\right)\right)} \cdot -2 \]
  6. Applied rewrites99.7%

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

Alternative 4: 99.3% 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 54.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  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-*.f6499.4

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

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

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

Alternative 5: 79.6% accurate, 1.9× speedup?

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

\\
\left(-\varepsilon\right) \cdot \sin x
\end{array}
Derivation
  1. Initial program 54.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  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. associate-*r*N/A

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

      \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
    3. mul-1-negN/A

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

      \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    5. lower-sin.f6480.8

      \[\leadsto \left(-\varepsilon\right) \cdot \color{blue}{\sin x} \]
  5. Applied rewrites80.8%

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

Alternative 6: 78.9% accurate, 5.9× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(-0.008333333333333333, x \cdot x, 0.16666666666666666\right) \cdot \varepsilon, x \cdot x, -\varepsilon\right) \cdot x \end{array} \]
(FPCore (x eps)
 :precision binary64
 (*
  (fma
   (* (fma -0.008333333333333333 (* x x) 0.16666666666666666) eps)
   (* x x)
   (- eps))
  x))
double code(double x, double eps) {
	return fma((fma(-0.008333333333333333, (x * x), 0.16666666666666666) * eps), (x * x), -eps) * x;
}
function code(x, eps)
	return Float64(fma(Float64(fma(-0.008333333333333333, Float64(x * x), 0.16666666666666666) * eps), Float64(x * x), Float64(-eps)) * x)
end
code[x_, eps_] := N[(N[(N[(N[(-0.008333333333333333 * N[(x * x), $MachinePrecision] + 0.16666666666666666), $MachinePrecision] * eps), $MachinePrecision] * N[(x * x), $MachinePrecision] + (-eps)), $MachinePrecision] * x), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\mathsf{fma}\left(-0.008333333333333333, x \cdot x, 0.16666666666666666\right) \cdot \varepsilon, x \cdot x, -\varepsilon\right) \cdot x
\end{array}
Derivation
  1. Initial program 54.7%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  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. associate-*r*N/A

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

      \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
    3. mul-1-negN/A

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

      \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
    5. lower-sin.f6480.8

      \[\leadsto \left(-\varepsilon\right) \cdot \color{blue}{\sin x} \]
  5. Applied rewrites80.8%

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

    \[\leadsto x \cdot \color{blue}{\left(-1 \cdot \varepsilon + {x}^{2} \cdot \left(\frac{-1}{120} \cdot \left(\varepsilon \cdot {x}^{2}\right) + \frac{1}{6} \cdot \varepsilon\right)\right)} \]
  7. Step-by-step derivation
    1. Applied rewrites80.1%

      \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(-0.008333333333333333, x \cdot x, 0.16666666666666666\right), x \cdot x, -\varepsilon\right) \cdot \color{blue}{x} \]
    2. Final simplification80.1%

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(-0.008333333333333333, x \cdot x, 0.16666666666666666\right) \cdot \varepsilon, x \cdot x, -\varepsilon\right) \cdot x \]
    3. Add Preprocessing

    Alternative 7: 78.6% 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 54.7%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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. associate-*r*N/A

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

        \[\leadsto \color{blue}{\left(-1 \cdot \varepsilon\right) \cdot \sin x} \]
      3. mul-1-negN/A

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

        \[\leadsto \color{blue}{\left(-\varepsilon\right)} \cdot \sin x \]
      5. lower-sin.f6480.8

        \[\leadsto \left(-\varepsilon\right) \cdot \color{blue}{\sin x} \]
    5. Applied rewrites80.8%

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

      \[\leadsto -1 \cdot \color{blue}{\left(\varepsilon \cdot x\right)} \]
    7. Step-by-step derivation
      1. Applied rewrites80.1%

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

      Alternative 8: 50.1% 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 54.7%

        \[\cos \left(x + \varepsilon\right) - \cos x \]
      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.f6453.5

          \[\leadsto \color{blue}{\cos \varepsilon} - 1 \]
      5. Applied rewrites53.5%

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

        \[\leadsto 1 - 1 \]
      7. Step-by-step derivation
        1. Applied rewrites53.5%

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

        Developer Target 1: 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 2024254 
        (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 (pow (cbrt (* -2 (sin (* 1/2 (fma 2 x eps))) (sin (* 1/2 eps)))) 3))
        
          (- (cos (+ x eps)) (cos x)))