2cos (problem 3.3.5)

Percentage Accurate: 51.4% → 99.8%
Time: 16.1s
Alternatives: 12
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 12 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: 99.8% accurate, 0.4× speedup?

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

\\
\begin{array}{l}
t_0 := \sin \left(0.5 \cdot \varepsilon\right)\\
\left(\mathsf{fma}\left(\cos \left(0.5 \cdot \varepsilon\right), \sin x, t\_0 \cdot \cos x\right) \cdot t\_0\right) \cdot -2
\end{array}
\end{array}
Derivation
  1. Initial program 56.5%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  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. distribute-rgt-inN/A

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(\sin \left(1 \cdot x\right), \cos \left(\frac{1}{2} \cdot \varepsilon\right), \color{blue}{\cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  6. Applied rewrites99.8%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(1 \cdot x\right), \cos \left(0.5 \cdot \varepsilon\right), \cos \left(1 \cdot x\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)} \cdot \sin \left(0.5 \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  7. Taylor expanded in x 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. lower-cos.f64N/A

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

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

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

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

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(\cos \left(\frac{1}{2} \cdot \varepsilon\right), \sin x, \sin \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \cos x\right) \cdot \color{blue}{\sin \left(\frac{1}{2} \cdot \varepsilon\right)}\right) \cdot -2 \]
    14. lower-*.f6499.8

      \[\leadsto \left(\mathsf{fma}\left(\cos \left(0.5 \cdot \varepsilon\right), \sin x, \sin \left(0.5 \cdot \varepsilon\right) \cdot \cos x\right) \cdot \sin \color{blue}{\left(0.5 \cdot \varepsilon\right)}\right) \cdot -2 \]
  9. Applied rewrites99.8%

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

Alternative 2: 99.4% accurate, 0.5× speedup?

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

\\
\left(\mathsf{fma}\left(\cos \left(0.5 \cdot \varepsilon\right), \sin x, \left(\cos x \cdot \mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right)\right) \cdot \varepsilon\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right) \cdot -2
\end{array}
Derivation
  1. Initial program 56.5%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  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. distribute-rgt-inN/A

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(\sin \left(1 \cdot x\right), \cos \left(\frac{1}{2} \cdot \varepsilon\right), \color{blue}{\cos \left(\left(2 \cdot x\right) \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)}\right) \cdot \sin \left(\frac{1}{2} \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  6. Applied rewrites99.8%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\sin \left(1 \cdot x\right), \cos \left(0.5 \cdot \varepsilon\right), \cos \left(1 \cdot x\right) \cdot \sin \left(0.5 \cdot \varepsilon\right)\right)} \cdot \sin \left(0.5 \cdot \left(0 + \varepsilon\right)\right)\right) \cdot -2 \]
  7. Taylor expanded in x 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. lower-cos.f64N/A

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

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

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

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

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(\cos \left(\frac{1}{2} \cdot \varepsilon\right), \sin x, \sin \left(\frac{1}{2} \cdot \varepsilon\right) \cdot \cos x\right) \cdot \color{blue}{\sin \left(\frac{1}{2} \cdot \varepsilon\right)}\right) \cdot -2 \]
    14. lower-*.f6499.8

      \[\leadsto \left(\mathsf{fma}\left(\cos \left(0.5 \cdot \varepsilon\right), \sin x, \sin \left(0.5 \cdot \varepsilon\right) \cdot \cos x\right) \cdot \sin \color{blue}{\left(0.5 \cdot \varepsilon\right)}\right) \cdot -2 \]
  9. Applied rewrites99.8%

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

    \[\leadsto \left(\mathsf{fma}\left(\cos \left(\frac{1}{2} \cdot \varepsilon\right), \sin x, \varepsilon \cdot \left(\frac{-1}{48} \cdot \left({\varepsilon}^{2} \cdot \cos x\right) + \frac{1}{2} \cdot \cos x\right)\right) \cdot \sin \left(\frac{1}{2} \cdot \varepsilon\right)\right) \cdot -2 \]
  11. Step-by-step derivation
    1. Applied rewrites99.8%

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

    Alternative 3: 99.3% accurate, 0.6× speedup?

    \[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(\cos x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right), \left(\sin x \cdot \varepsilon\right) \cdot 0.16666666666666666\right), \varepsilon, -\sin x\right) \cdot \varepsilon \end{array} \]
    (FPCore (x eps)
     :precision binary64
     (*
      (fma
       (fma
        (cos x)
        (fma (* eps eps) 0.041666666666666664 -0.5)
        (* (* (sin x) eps) 0.16666666666666666))
       eps
       (- (sin x)))
      eps))
    double code(double x, double eps) {
    	return fma(fma(cos(x), fma((eps * eps), 0.041666666666666664, -0.5), ((sin(x) * eps) * 0.16666666666666666)), eps, -sin(x)) * eps;
    }
    
    function code(x, eps)
    	return Float64(fma(fma(cos(x), fma(Float64(eps * eps), 0.041666666666666664, -0.5), Float64(Float64(sin(x) * eps) * 0.16666666666666666)), eps, Float64(-sin(x))) * eps)
    end
    
    code[x_, eps_] := N[(N[(N[(N[Cos[x], $MachinePrecision] * N[(N[(eps * eps), $MachinePrecision] * 0.041666666666666664 + -0.5), $MachinePrecision] + N[(N[(N[Sin[x], $MachinePrecision] * eps), $MachinePrecision] * 0.16666666666666666), $MachinePrecision]), $MachinePrecision] * eps + (-N[Sin[x], $MachinePrecision])), $MachinePrecision] * eps), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \mathsf{fma}\left(\mathsf{fma}\left(\cos x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right), \left(\sin x \cdot \varepsilon\right) \cdot 0.16666666666666666\right), \varepsilon, -\sin x\right) \cdot \varepsilon
    \end{array}
    
    Derivation
    1. Initial program 56.5%

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

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
      2. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
    5. Applied rewrites99.7%

      \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
    6. Taylor expanded in eps around 0

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
    7. Applied rewrites99.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\cos x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right), \left(\sin x \cdot \varepsilon\right) \cdot 0.16666666666666666\right), \varepsilon, -\sin x\right) \cdot \varepsilon} \]
    8. Add Preprocessing

    Alternative 4: 99.4% accurate, 1.4× speedup?

    \[\begin{array}{l} \\ \left(\sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666, \varepsilon \cdot \varepsilon, -0.020833333333333332\right), \varepsilon \cdot \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \end{array} \]
    (FPCore (x eps)
     :precision binary64
     (*
      (*
       (sin (fma eps 0.5 x))
       (*
        (fma
         (fma 0.00026041666666666666 (* eps eps) -0.020833333333333332)
         (* eps eps)
         0.5)
        eps))
      -2.0))
    double code(double x, double eps) {
    	return (sin(fma(eps, 0.5, x)) * (fma(fma(0.00026041666666666666, (eps * eps), -0.020833333333333332), (eps * eps), 0.5) * eps)) * -2.0;
    }
    
    function code(x, eps)
    	return Float64(Float64(sin(fma(eps, 0.5, x)) * Float64(fma(fma(0.00026041666666666666, Float64(eps * eps), -0.020833333333333332), Float64(eps * eps), 0.5) * eps)) * -2.0)
    end
    
    code[x_, eps_] := N[(N[(N[Sin[N[(eps * 0.5 + x), $MachinePrecision]], $MachinePrecision] * N[(N[(N[(0.00026041666666666666 * N[(eps * eps), $MachinePrecision] + -0.020833333333333332), $MachinePrecision] * N[(eps * eps), $MachinePrecision] + 0.5), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \left(\sin \left(\mathsf{fma}\left(\varepsilon, 0.5, x\right)\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666, \varepsilon \cdot \varepsilon, -0.020833333333333332\right), \varepsilon \cdot \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2
    \end{array}
    
    Derivation
    1. Initial program 56.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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. lower-fma.f64N/A

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

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

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

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

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

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

        \[\leadsto \left(\sin \left(\frac{1}{2} \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{3840}, \varepsilon \cdot \varepsilon, \frac{-1}{48}\right), \color{blue}{\varepsilon \cdot \varepsilon}, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
      12. lower-*.f6499.7

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

      \[\leadsto \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(0.00026041666666666666, \varepsilon \cdot \varepsilon, -0.020833333333333332\right), \varepsilon \cdot \varepsilon, 0.5\right) \cdot \varepsilon\right)}\right) \cdot -2 \]
    8. Step-by-step derivation
      1. lift-*.f64N/A

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

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

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

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

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

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

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

        \[\leadsto \left(\sin \left(\varepsilon \cdot \frac{1}{2} + \color{blue}{x}\right) \cdot \left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{3840}, \varepsilon \cdot \varepsilon, \frac{-1}{48}\right), \varepsilon \cdot \varepsilon, \frac{1}{2}\right) \cdot \varepsilon\right)\right) \cdot -2 \]
      9. lower-fma.f6499.7

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

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

    Alternative 5: 99.3% accurate, 1.5× speedup?

    \[\begin{array}{l} \\ \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2 \end{array} \]
    (FPCore (x eps)
     :precision binary64
     (*
      (*
       (sin (* 0.5 (fma 2.0 x eps)))
       (* (fma (* -0.020833333333333332 eps) eps 0.5) eps))
      -2.0))
    double code(double x, double eps) {
    	return (sin((0.5 * fma(2.0, x, eps))) * (fma((-0.020833333333333332 * eps), eps, 0.5) * eps)) * -2.0;
    }
    
    function code(x, eps)
    	return Float64(Float64(sin(Float64(0.5 * fma(2.0, x, eps))) * Float64(fma(Float64(-0.020833333333333332 * eps), eps, 0.5) * eps)) * -2.0)
    end
    
    code[x_, eps_] := N[(N[(N[Sin[N[(0.5 * N[(2.0 * x + eps), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(N[(N[(-0.020833333333333332 * eps), $MachinePrecision] * eps + 0.5), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \left(\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(\mathsf{fma}\left(-0.020833333333333332 \cdot \varepsilon, \varepsilon, 0.5\right) \cdot \varepsilon\right)\right) \cdot -2
    \end{array}
    
    Derivation
    1. Initial program 56.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    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-*.f6499.7

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

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

    Alternative 6: 98.6% accurate, 1.7× speedup?

    \[\begin{array}{l} \\ \left(\mathsf{fma}\left(\varepsilon, 0.16666666666666666 \cdot x, -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon \end{array} \]
    (FPCore (x eps)
     :precision binary64
     (* (- (* (fma eps (* 0.16666666666666666 x) -0.5) eps) (sin x)) eps))
    double code(double x, double eps) {
    	return ((fma(eps, (0.16666666666666666 * x), -0.5) * eps) - sin(x)) * eps;
    }
    
    function code(x, eps)
    	return Float64(Float64(Float64(fma(eps, Float64(0.16666666666666666 * x), -0.5) * eps) - sin(x)) * eps)
    end
    
    code[x_, eps_] := N[(N[(N[(N[(eps * N[(0.16666666666666666 * x), $MachinePrecision] + -0.5), $MachinePrecision] * eps), $MachinePrecision] - N[Sin[x], $MachinePrecision]), $MachinePrecision] * eps), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \left(\mathsf{fma}\left(\varepsilon, 0.16666666666666666 \cdot x, -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon
    \end{array}
    
    Derivation
    1. Initial program 56.5%

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

      \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
      2. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
    5. Applied rewrites99.7%

      \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
    6. Taylor expanded in x around 0

      \[\leadsto \left(\left(\left(\frac{1}{24} \cdot {\varepsilon}^{2} + \frac{1}{6} \cdot \left(\varepsilon \cdot x\right)\right) - \frac{1}{2}\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon \]
    7. Step-by-step derivation
      1. Applied rewrites99.1%

        \[\leadsto \left(\mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(0.16666666666666666, x, 0.041666666666666664 \cdot \varepsilon\right), -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon \]
      2. Taylor expanded in x around inf

        \[\leadsto \left(\mathsf{fma}\left(\varepsilon, \frac{1}{6} \cdot x, \frac{-1}{2}\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon \]
      3. Step-by-step derivation
        1. Applied rewrites99.1%

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

        Alternative 7: 97.9% accurate, 2.7× speedup?

        \[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-0.027777777777777776, \varepsilon \cdot \varepsilon, 0.16666666666666666\right), x, \mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right) \cdot \varepsilon\right), x, \mathsf{fma}\left(0.16666666666666666 \cdot \varepsilon, \varepsilon, -1\right)\right), x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon \end{array} \]
        (FPCore (x eps)
         :precision binary64
         (*
          (fma
           (fma
            (fma
             (fma -0.027777777777777776 (* eps eps) 0.16666666666666666)
             x
             (* (fma -0.020833333333333332 (* eps eps) 0.25) eps))
            x
            (fma (* 0.16666666666666666 eps) eps -1.0))
           x
           (* (fma (* eps eps) 0.041666666666666664 -0.5) eps))
          eps))
        double code(double x, double eps) {
        	return fma(fma(fma(fma(-0.027777777777777776, (eps * eps), 0.16666666666666666), x, (fma(-0.020833333333333332, (eps * eps), 0.25) * eps)), x, fma((0.16666666666666666 * eps), eps, -1.0)), x, (fma((eps * eps), 0.041666666666666664, -0.5) * eps)) * eps;
        }
        
        function code(x, eps)
        	return Float64(fma(fma(fma(fma(-0.027777777777777776, Float64(eps * eps), 0.16666666666666666), x, Float64(fma(-0.020833333333333332, Float64(eps * eps), 0.25) * eps)), x, fma(Float64(0.16666666666666666 * eps), eps, -1.0)), x, Float64(fma(Float64(eps * eps), 0.041666666666666664, -0.5) * eps)) * eps)
        end
        
        code[x_, eps_] := N[(N[(N[(N[(N[(-0.027777777777777776 * N[(eps * eps), $MachinePrecision] + 0.16666666666666666), $MachinePrecision] * x + N[(N[(-0.020833333333333332 * N[(eps * eps), $MachinePrecision] + 0.25), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision] * x + N[(N[(0.16666666666666666 * eps), $MachinePrecision] * eps + -1.0), $MachinePrecision]), $MachinePrecision] * x + N[(N[(N[(eps * eps), $MachinePrecision] * 0.041666666666666664 + -0.5), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision] * eps), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-0.027777777777777776, \varepsilon \cdot \varepsilon, 0.16666666666666666\right), x, \mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right) \cdot \varepsilon\right), x, \mathsf{fma}\left(0.16666666666666666 \cdot \varepsilon, \varepsilon, -1\right)\right), x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon
        \end{array}
        
        Derivation
        1. Initial program 56.5%

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

          \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
        4. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
          2. lower-*.f64N/A

            \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
        5. Applied rewrites99.7%

          \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
        6. Taylor expanded in x around 0

          \[\leadsto \left(\varepsilon \cdot \left(\frac{1}{24} \cdot {\varepsilon}^{2} - \frac{1}{2}\right) + x \cdot \left(\left(\frac{1}{6} \cdot {\varepsilon}^{2} + x \cdot \left(\varepsilon \cdot \left(\frac{1}{4} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right) + x \cdot \left(\frac{1}{6} + \frac{-1}{36} \cdot {\varepsilon}^{2}\right)\right)\right) - 1\right)\right) \cdot \varepsilon \]
        7. Step-by-step derivation
          1. Applied rewrites98.1%

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-0.027777777777777776, \varepsilon \cdot \varepsilon, 0.16666666666666666\right), x, \mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right) \cdot \varepsilon\right), x, \mathsf{fma}\left(0.16666666666666666 \cdot \varepsilon, \varepsilon, -1\right)\right), x, \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon \]
          2. Add Preprocessing

          Alternative 8: 97.6% accurate, 3.4× speedup?

          \[\begin{array}{l} \\ \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \end{array} \]
          (FPCore (x eps)
           :precision binary64
           (fma
            (*
             eps
             (fma
              eps
              (fma
               (fma -0.020833333333333332 (* eps eps) 0.25)
               x
               (* 0.16666666666666666 eps))
              -1.0))
            x
            (* (* (fma (* eps eps) 0.041666666666666664 -0.5) eps) eps)))
          double code(double x, double eps) {
          	return fma((eps * fma(eps, fma(fma(-0.020833333333333332, (eps * eps), 0.25), x, (0.16666666666666666 * eps)), -1.0)), x, ((fma((eps * eps), 0.041666666666666664, -0.5) * eps) * eps));
          }
          
          function code(x, eps)
          	return fma(Float64(eps * fma(eps, fma(fma(-0.020833333333333332, Float64(eps * eps), 0.25), x, Float64(0.16666666666666666 * eps)), -1.0)), x, Float64(Float64(fma(Float64(eps * eps), 0.041666666666666664, -0.5) * eps) * eps))
          end
          
          code[x_, eps_] := N[(N[(eps * N[(eps * N[(N[(-0.020833333333333332 * N[(eps * eps), $MachinePrecision] + 0.25), $MachinePrecision] * x + N[(0.16666666666666666 * eps), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision] * x + N[(N[(N[(N[(eps * eps), $MachinePrecision] * 0.041666666666666664 + -0.5), $MachinePrecision] * eps), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right)
          \end{array}
          
          Derivation
          1. Initial program 56.5%

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

            \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
          4. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
            2. lower-*.f64N/A

              \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
          5. Applied rewrites99.7%

            \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
          6. Taylor expanded in x around 0

            \[\leadsto x \cdot \left(\varepsilon \cdot \left(\frac{1}{6} \cdot {\varepsilon}^{2} - 1\right) + {\varepsilon}^{2} \cdot \left(x \cdot \left(\frac{1}{4} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right)\right)\right) + \color{blue}{{\varepsilon}^{2} \cdot \left(\frac{1}{24} \cdot {\varepsilon}^{2} - \frac{1}{2}\right)} \]
          7. Applied rewrites97.6%

            \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), \color{blue}{x}, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
          8. Add Preprocessing

          Alternative 9: 97.6% accurate, 6.9× speedup?

          \[\begin{array}{l} \\ \mathsf{fma}\left(-\varepsilon, x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \end{array} \]
          (FPCore (x eps)
           :precision binary64
           (fma (- eps) x (* (* (fma (* eps eps) 0.041666666666666664 -0.5) eps) eps)))
          double code(double x, double eps) {
          	return fma(-eps, x, ((fma((eps * eps), 0.041666666666666664, -0.5) * eps) * eps));
          }
          
          function code(x, eps)
          	return fma(Float64(-eps), x, Float64(Float64(fma(Float64(eps * eps), 0.041666666666666664, -0.5) * eps) * eps))
          end
          
          code[x_, eps_] := N[((-eps) * x + N[(N[(N[(N[(eps * eps), $MachinePrecision] * 0.041666666666666664 + -0.5), $MachinePrecision] * eps), $MachinePrecision] * eps), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          \mathsf{fma}\left(-\varepsilon, x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right)
          \end{array}
          
          Derivation
          1. Initial program 56.5%

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

            \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
          4. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
            2. lower-*.f64N/A

              \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
          5. Applied rewrites99.7%

            \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
          6. Taylor expanded in x around 0

            \[\leadsto x \cdot \left(\varepsilon \cdot \left(\frac{1}{6} \cdot {\varepsilon}^{2} - 1\right) + {\varepsilon}^{2} \cdot \left(x \cdot \left(\frac{1}{4} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right)\right)\right) + \color{blue}{{\varepsilon}^{2} \cdot \left(\frac{1}{24} \cdot {\varepsilon}^{2} - \frac{1}{2}\right)} \]
          7. Applied rewrites97.6%

            \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), \color{blue}{x}, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
          8. Taylor expanded in eps around 0

            \[\leadsto \mathsf{fma}\left(-1 \cdot \varepsilon, x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, \frac{1}{24}, \frac{-1}{2}\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
          9. Step-by-step derivation
            1. Applied rewrites97.6%

              \[\leadsto \mathsf{fma}\left(-\varepsilon, x, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
            2. Add Preprocessing

            Alternative 10: 97.4% accurate, 8.3× speedup?

            \[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(0.25 \cdot x, x, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon \end{array} \]
            (FPCore (x eps)
             :precision binary64
             (* (fma (fma (* 0.25 x) x -0.5) eps (- x)) eps))
            double code(double x, double eps) {
            	return fma(fma((0.25 * x), x, -0.5), eps, -x) * eps;
            }
            
            function code(x, eps)
            	return Float64(fma(fma(Float64(0.25 * x), x, -0.5), eps, Float64(-x)) * eps)
            end
            
            code[x_, eps_] := N[(N[(N[(N[(0.25 * x), $MachinePrecision] * x + -0.5), $MachinePrecision] * eps + (-x)), $MachinePrecision] * eps), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \mathsf{fma}\left(\mathsf{fma}\left(0.25 \cdot x, x, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon
            \end{array}
            
            Derivation
            1. Initial program 56.5%

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

              \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
            4. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
              2. lower-*.f64N/A

                \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
            5. Applied rewrites99.7%

              \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
            6. Taylor expanded in x around 0

              \[\leadsto x \cdot \left(\varepsilon \cdot \left(\frac{1}{6} \cdot {\varepsilon}^{2} - 1\right) + {\varepsilon}^{2} \cdot \left(x \cdot \left(\frac{1}{4} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right)\right)\right) + \color{blue}{{\varepsilon}^{2} \cdot \left(\frac{1}{24} \cdot {\varepsilon}^{2} - \frac{1}{2}\right)} \]
            7. Applied rewrites97.6%

              \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), \color{blue}{x}, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
            8. Taylor expanded in eps around 0

              \[\leadsto \varepsilon \cdot \left(-1 \cdot x + \color{blue}{\varepsilon \cdot \left(\frac{1}{4} \cdot {x}^{2} - \frac{1}{2}\right)}\right) \]
            9. Step-by-step derivation
              1. Applied rewrites97.5%

                \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.25 \cdot x, x, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon \]
              2. Add Preprocessing

              Alternative 11: 97.4% accurate, 14.8× speedup?

              \[\begin{array}{l} \\ \varepsilon \cdot \left(-0.5 \cdot \varepsilon - x\right) \end{array} \]
              (FPCore (x eps) :precision binary64 (* eps (- (* -0.5 eps) x)))
              double code(double x, double eps) {
              	return eps * ((-0.5 * eps) - x);
              }
              
              real(8) function code(x, eps)
                  real(8), intent (in) :: x
                  real(8), intent (in) :: eps
                  code = eps * (((-0.5d0) * eps) - x)
              end function
              
              public static double code(double x, double eps) {
              	return eps * ((-0.5 * eps) - x);
              }
              
              def code(x, eps):
              	return eps * ((-0.5 * eps) - x)
              
              function code(x, eps)
              	return Float64(eps * Float64(Float64(-0.5 * eps) - x))
              end
              
              function tmp = code(x, eps)
              	tmp = eps * ((-0.5 * eps) - x);
              end
              
              code[x_, eps_] := N[(eps * N[(N[(-0.5 * eps), $MachinePrecision] - x), $MachinePrecision]), $MachinePrecision]
              
              \begin{array}{l}
              
              \\
              \varepsilon \cdot \left(-0.5 \cdot \varepsilon - x\right)
              \end{array}
              
              Derivation
              1. Initial program 56.5%

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

                \[\leadsto \color{blue}{\varepsilon \cdot \left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right)} \]
              4. Step-by-step derivation
                1. *-commutativeN/A

                  \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
                2. lower-*.f64N/A

                  \[\leadsto \color{blue}{\left(\varepsilon \cdot \left(\frac{-1}{2} \cdot \cos x + \varepsilon \cdot \left(\frac{1}{24} \cdot \left(\varepsilon \cdot \cos x\right) - \frac{-1}{6} \cdot \sin x\right)\right) - \sin x\right) \cdot \varepsilon} \]
              5. Applied rewrites99.7%

                \[\leadsto \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin x, 0.16666666666666666, \left(\cos x \cdot \varepsilon\right) \cdot 0.041666666666666664\right), \varepsilon, \cos x \cdot -0.5\right) \cdot \varepsilon - \sin x\right) \cdot \varepsilon} \]
              6. Taylor expanded in x around 0

                \[\leadsto x \cdot \left(\varepsilon \cdot \left(\frac{1}{6} \cdot {\varepsilon}^{2} - 1\right) + {\varepsilon}^{2} \cdot \left(x \cdot \left(\frac{1}{4} + \frac{-1}{48} \cdot {\varepsilon}^{2}\right)\right)\right) + \color{blue}{{\varepsilon}^{2} \cdot \left(\frac{1}{24} \cdot {\varepsilon}^{2} - \frac{1}{2}\right)} \]
              7. Applied rewrites97.6%

                \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \mathsf{fma}\left(\varepsilon, \mathsf{fma}\left(\mathsf{fma}\left(-0.020833333333333332, \varepsilon \cdot \varepsilon, 0.25\right), x, 0.16666666666666666 \cdot \varepsilon\right), -1\right), \color{blue}{x}, \left(\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.041666666666666664, -0.5\right) \cdot \varepsilon\right) \cdot \varepsilon\right) \]
              8. Taylor expanded in eps around 0

                \[\leadsto \varepsilon \cdot \left(-1 \cdot x + \color{blue}{\varepsilon \cdot \left(\frac{1}{4} \cdot {x}^{2} - \frac{1}{2}\right)}\right) \]
              9. Step-by-step derivation
                1. Applied rewrites97.5%

                  \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.25 \cdot x, x, -0.5\right), \varepsilon, -x\right) \cdot \varepsilon \]
                2. Taylor expanded in x around 0

                  \[\leadsto -1 \cdot \left(\varepsilon \cdot x\right) + \frac{-1}{2} \cdot {\varepsilon}^{\color{blue}{2}} \]
                3. Step-by-step derivation
                  1. Applied rewrites97.5%

                    \[\leadsto \varepsilon \cdot \left(-0.5 \cdot \varepsilon - x\right) \]
                  2. Add Preprocessing

                  Alternative 12: 78.3% 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 56.5%

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

                      \[\leadsto \color{blue}{\left(-\sin x\right)} \cdot \varepsilon \]
                    6. lower-sin.f6481.6

                      \[\leadsto \left(-\color{blue}{\sin x}\right) \cdot \varepsilon \]
                  5. Applied rewrites81.6%

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

                    \[\leadsto \left(-1 \cdot x\right) \cdot \varepsilon \]
                  7. Step-by-step derivation
                    1. Applied rewrites80.3%

                      \[\leadsto \left(-x\right) \cdot \varepsilon \]
                    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 2024302 
                    (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)))