cos2 (problem 3.4.1)

Percentage Accurate: 50.5% → 99.8%
Time: 8.5s
Alternatives: 10
Speedup: 120.0×

Specification

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

\\
\frac{1 - \cos x}{x \cdot 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 10 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: 50.5% accurate, 1.0× speedup?

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

\\
\frac{1 - \cos x}{x \cdot x}
\end{array}

Alternative 1: 99.8% accurate, 0.5× speedup?

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

\\
\frac{\frac{\tan \left(x \cdot 0.5\right)}{x}}{\frac{x}{\sin x}}
\end{array}
Derivation
  1. Initial program 48.0%

    \[\frac{1 - \cos x}{x \cdot x} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    2. lift--.f64N/A

      \[\leadsto \frac{\color{blue}{1 - \cos x}}{x \cdot x} \]
    3. flip--N/A

      \[\leadsto \frac{\color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{1 + \cos x}}}{x \cdot x} \]
    4. associate-/l/N/A

      \[\leadsto \color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)}} \]
    5. metadata-evalN/A

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

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

      \[\leadsto \frac{1 - \cos x \cdot \color{blue}{\cos x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    8. 1-sub-cosN/A

      \[\leadsto \frac{\color{blue}{\sin x \cdot \sin x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    9. times-fracN/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    10. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    11. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x}} \cdot \frac{\sin x}{1 + \cos x} \]
    12. lower-sin.f64N/A

      \[\leadsto \frac{\color{blue}{\sin x}}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x} \]
    13. lift-cos.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \color{blue}{\cos x}} \]
    14. hang-0p-tanN/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    15. lower-tan.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    16. lower-/.f6473.9

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \tan \color{blue}{\left(\frac{x}{2}\right)} \]
  4. Applied rewrites73.9%

    \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \tan \left(\frac{x}{2}\right)} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

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

      \[\leadsto \color{blue}{\tan \left(\frac{x}{2}\right) \cdot \frac{\sin x}{x \cdot x}} \]
    3. lift-/.f64N/A

      \[\leadsto \tan \left(\frac{x}{2}\right) \cdot \color{blue}{\frac{\sin x}{x \cdot x}} \]
    4. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{x \cdot x}} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{\color{blue}{x \cdot x}} \]
    6. times-fracN/A

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

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right)}{x} \cdot \frac{\sin x}{x}} \]
    8. lower-/.f64N/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{x}{2}\right)}}{x} \cdot \frac{\sin x}{x} \]
    10. clear-numN/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{\frac{2}{x}}\right)}}{x} \cdot \frac{\sin x}{x} \]
    11. associate-/r/N/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    12. metadata-evalN/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    14. lower-/.f6499.8

      \[\leadsto \frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \color{blue}{\frac{\sin x}{x}} \]
  6. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \frac{\sin x}{x}} \]
  7. Step-by-step derivation
    1. lift-*.f64N/A

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

      \[\leadsto \frac{\tan \left(\frac{1}{2} \cdot x\right)}{x} \cdot \color{blue}{\frac{\sin x}{x}} \]
    3. clear-numN/A

      \[\leadsto \frac{\tan \left(\frac{1}{2} \cdot x\right)}{x} \cdot \color{blue}{\frac{1}{\frac{x}{\sin x}}} \]
    4. un-div-invN/A

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

      \[\leadsto \color{blue}{\frac{\frac{\tan \left(\frac{1}{2} \cdot x\right)}{x}}{\frac{x}{\sin x}}} \]
    6. lift-*.f64N/A

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

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

      \[\leadsto \frac{\frac{\tan \color{blue}{\left(x \cdot \frac{1}{2}\right)}}{x}}{\frac{x}{\sin x}} \]
    9. lower-/.f6499.8

      \[\leadsto \frac{\frac{\tan \left(x \cdot 0.5\right)}{x}}{\color{blue}{\frac{x}{\sin x}}} \]
  8. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\frac{\tan \left(x \cdot 0.5\right)}{x}}{\frac{x}{\sin x}}} \]
  9. Add Preprocessing

Alternative 2: 99.8% accurate, 0.5× speedup?

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

\\
\frac{\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \sin x}{x}
\end{array}
Derivation
  1. Initial program 48.0%

    \[\frac{1 - \cos x}{x \cdot x} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    2. lift--.f64N/A

      \[\leadsto \frac{\color{blue}{1 - \cos x}}{x \cdot x} \]
    3. flip--N/A

      \[\leadsto \frac{\color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{1 + \cos x}}}{x \cdot x} \]
    4. associate-/l/N/A

      \[\leadsto \color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)}} \]
    5. metadata-evalN/A

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

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

      \[\leadsto \frac{1 - \cos x \cdot \color{blue}{\cos x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    8. 1-sub-cosN/A

      \[\leadsto \frac{\color{blue}{\sin x \cdot \sin x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    9. times-fracN/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    10. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    11. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x}} \cdot \frac{\sin x}{1 + \cos x} \]
    12. lower-sin.f64N/A

      \[\leadsto \frac{\color{blue}{\sin x}}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x} \]
    13. lift-cos.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \color{blue}{\cos x}} \]
    14. hang-0p-tanN/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    15. lower-tan.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    16. lower-/.f6473.9

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \tan \color{blue}{\left(\frac{x}{2}\right)} \]
  4. Applied rewrites73.9%

    \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \tan \left(\frac{x}{2}\right)} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

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

      \[\leadsto \color{blue}{\tan \left(\frac{x}{2}\right) \cdot \frac{\sin x}{x \cdot x}} \]
    3. lift-/.f64N/A

      \[\leadsto \tan \left(\frac{x}{2}\right) \cdot \color{blue}{\frac{\sin x}{x \cdot x}} \]
    4. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{x \cdot x}} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{\color{blue}{x \cdot x}} \]
    6. times-fracN/A

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

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right)}{x} \cdot \frac{\sin x}{x}} \]
    8. lower-/.f64N/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{x}{2}\right)}}{x} \cdot \frac{\sin x}{x} \]
    10. clear-numN/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{\frac{2}{x}}\right)}}{x} \cdot \frac{\sin x}{x} \]
    11. associate-/r/N/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    12. metadata-evalN/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    14. lower-/.f6499.8

      \[\leadsto \frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \color{blue}{\frac{\sin x}{x}} \]
  6. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \frac{\sin x}{x}} \]
  7. Step-by-step derivation
    1. lift-*.f64N/A

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

      \[\leadsto \frac{\tan \left(\frac{1}{2} \cdot x\right)}{x} \cdot \color{blue}{\frac{\sin x}{x}} \]
    3. clear-numN/A

      \[\leadsto \frac{\tan \left(\frac{1}{2} \cdot x\right)}{x} \cdot \color{blue}{\frac{1}{\frac{x}{\sin x}}} \]
    4. un-div-invN/A

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

      \[\leadsto \color{blue}{\frac{\frac{\tan \left(\frac{1}{2} \cdot x\right)}{x}}{\frac{x}{\sin x}}} \]
    6. lift-*.f64N/A

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

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

      \[\leadsto \frac{\frac{\tan \color{blue}{\left(x \cdot \frac{1}{2}\right)}}{x}}{\frac{x}{\sin x}} \]
    9. lower-/.f6499.8

      \[\leadsto \frac{\frac{\tan \left(x \cdot 0.5\right)}{x}}{\color{blue}{\frac{x}{\sin x}}} \]
  8. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\frac{\tan \left(x \cdot 0.5\right)}{x}}{\frac{x}{\sin x}}} \]
  9. Step-by-step derivation
    1. lift-/.f64N/A

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

      \[\leadsto \frac{\frac{\tan \left(x \cdot \frac{1}{2}\right)}{x}}{\color{blue}{\frac{x}{\sin x}}} \]
    3. associate-/r/N/A

      \[\leadsto \color{blue}{\frac{\frac{\tan \left(x \cdot \frac{1}{2}\right)}{x}}{x} \cdot \sin x} \]
    4. associate-*l/N/A

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

      \[\leadsto \color{blue}{\frac{\frac{\tan \left(x \cdot \frac{1}{2}\right)}{x} \cdot \sin x}{x}} \]
    6. lower-*.f6499.8

      \[\leadsto \frac{\color{blue}{\frac{\tan \left(x \cdot 0.5\right)}{x} \cdot \sin x}}{x} \]
    7. lift-*.f64N/A

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

      \[\leadsto \frac{\frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \sin x}{x} \]
    9. lower-*.f6499.8

      \[\leadsto \frac{\frac{\tan \color{blue}{\left(0.5 \cdot x\right)}}{x} \cdot \sin x}{x} \]
  10. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \sin x}{x}} \]
  11. Add Preprocessing

Alternative 3: 99.8% accurate, 0.5× speedup?

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

\\
\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \frac{\sin x}{x}
\end{array}
Derivation
  1. Initial program 48.0%

    \[\frac{1 - \cos x}{x \cdot x} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    2. lift--.f64N/A

      \[\leadsto \frac{\color{blue}{1 - \cos x}}{x \cdot x} \]
    3. flip--N/A

      \[\leadsto \frac{\color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{1 + \cos x}}}{x \cdot x} \]
    4. associate-/l/N/A

      \[\leadsto \color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)}} \]
    5. metadata-evalN/A

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

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

      \[\leadsto \frac{1 - \cos x \cdot \color{blue}{\cos x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    8. 1-sub-cosN/A

      \[\leadsto \frac{\color{blue}{\sin x \cdot \sin x}}{\left(x \cdot x\right) \cdot \left(1 + \cos x\right)} \]
    9. times-fracN/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    10. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x}} \]
    11. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x}} \cdot \frac{\sin x}{1 + \cos x} \]
    12. lower-sin.f64N/A

      \[\leadsto \frac{\color{blue}{\sin x}}{x \cdot x} \cdot \frac{\sin x}{1 + \cos x} \]
    13. lift-cos.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{1 + \color{blue}{\cos x}} \]
    14. hang-0p-tanN/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    15. lower-tan.f64N/A

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \color{blue}{\tan \left(\frac{x}{2}\right)} \]
    16. lower-/.f6473.9

      \[\leadsto \frac{\sin x}{x \cdot x} \cdot \tan \color{blue}{\left(\frac{x}{2}\right)} \]
  4. Applied rewrites73.9%

    \[\leadsto \color{blue}{\frac{\sin x}{x \cdot x} \cdot \tan \left(\frac{x}{2}\right)} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

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

      \[\leadsto \color{blue}{\tan \left(\frac{x}{2}\right) \cdot \frac{\sin x}{x \cdot x}} \]
    3. lift-/.f64N/A

      \[\leadsto \tan \left(\frac{x}{2}\right) \cdot \color{blue}{\frac{\sin x}{x \cdot x}} \]
    4. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{x \cdot x}} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{\tan \left(\frac{x}{2}\right) \cdot \sin x}{\color{blue}{x \cdot x}} \]
    6. times-fracN/A

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

      \[\leadsto \color{blue}{\frac{\tan \left(\frac{x}{2}\right)}{x} \cdot \frac{\sin x}{x}} \]
    8. lower-/.f64N/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{x}{2}\right)}}{x} \cdot \frac{\sin x}{x} \]
    10. clear-numN/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{\frac{2}{x}}\right)}}{x} \cdot \frac{\sin x}{x} \]
    11. associate-/r/N/A

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    12. metadata-evalN/A

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

      \[\leadsto \frac{\tan \color{blue}{\left(\frac{1}{2} \cdot x\right)}}{x} \cdot \frac{\sin x}{x} \]
    14. lower-/.f6499.8

      \[\leadsto \frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \color{blue}{\frac{\sin x}{x}} \]
  6. Applied rewrites99.8%

    \[\leadsto \color{blue}{\frac{\tan \left(0.5 \cdot x\right)}{x} \cdot \frac{\sin x}{x}} \]
  7. Add Preprocessing

Alternative 4: 75.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 0.033:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{-1}{x} \cdot \left(\cos x - 1\right)}{x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 0.033)
   (fma (fma 0.001388888888888889 (* x x) -0.041666666666666664) (* x x) 0.5)
   (/ (* (/ -1.0 x) (- (cos x) 1.0)) x)))
double code(double x) {
	double tmp;
	if (x <= 0.033) {
		tmp = fma(fma(0.001388888888888889, (x * x), -0.041666666666666664), (x * x), 0.5);
	} else {
		tmp = ((-1.0 / x) * (cos(x) - 1.0)) / x;
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (x <= 0.033)
		tmp = fma(fma(0.001388888888888889, Float64(x * x), -0.041666666666666664), Float64(x * x), 0.5);
	else
		tmp = Float64(Float64(Float64(-1.0 / x) * Float64(cos(x) - 1.0)) / x);
	end
	return tmp
end
code[x_] := If[LessEqual[x, 0.033], N[(N[(0.001388888888888889 * N[(x * x), $MachinePrecision] + -0.041666666666666664), $MachinePrecision] * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision], N[(N[(N[(-1.0 / x), $MachinePrecision] * N[(N[Cos[x], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 0.033:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.033000000000000002

    1. Initial program 34.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) + \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) \cdot {x}^{2}} + \frac{1}{2} \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}, {x}^{2}, \frac{1}{2}\right)} \]
      4. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \left(\mathsf{neg}\left(\frac{1}{24}\right)\right)}, {x}^{2}, \frac{1}{2}\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} + \color{blue}{\frac{-1}{24}}, {x}^{2}, \frac{1}{2}\right) \]
      6. lower-fma.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{-1}{24}\right)}, {x}^{2}, \frac{1}{2}\right) \]
      7. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      8. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{-1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right) \]
      10. lower-*.f6467.8

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), \color{blue}{x \cdot x}, 0.5\right) \]
    5. Applied rewrites67.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)} \]

    if 0.033000000000000002 < x

    1. Initial program 97.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Applied rewrites99.5%

      \[\leadsto \color{blue}{\frac{\frac{1 - \cos x}{x}}{x}} \]
    4. Applied rewrites99.5%

      \[\leadsto \frac{\color{blue}{\frac{-1}{x} \cdot \left(\cos x - 1\right)}}{x} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 5: 75.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 0.033:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{1 - \cos x}{x}}{x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 0.033)
   (fma (fma 0.001388888888888889 (* x x) -0.041666666666666664) (* x x) 0.5)
   (/ (/ (- 1.0 (cos x)) x) x)))
double code(double x) {
	double tmp;
	if (x <= 0.033) {
		tmp = fma(fma(0.001388888888888889, (x * x), -0.041666666666666664), (x * x), 0.5);
	} else {
		tmp = ((1.0 - cos(x)) / x) / x;
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (x <= 0.033)
		tmp = fma(fma(0.001388888888888889, Float64(x * x), -0.041666666666666664), Float64(x * x), 0.5);
	else
		tmp = Float64(Float64(Float64(1.0 - cos(x)) / x) / x);
	end
	return tmp
end
code[x_] := If[LessEqual[x, 0.033], N[(N[(0.001388888888888889 * N[(x * x), $MachinePrecision] + -0.041666666666666664), $MachinePrecision] * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision], N[(N[(N[(1.0 - N[Cos[x], $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision] / x), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 0.033:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{\frac{1 - \cos x}{x}}{x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.033000000000000002

    1. Initial program 34.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) + \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) \cdot {x}^{2}} + \frac{1}{2} \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}, {x}^{2}, \frac{1}{2}\right)} \]
      4. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \left(\mathsf{neg}\left(\frac{1}{24}\right)\right)}, {x}^{2}, \frac{1}{2}\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} + \color{blue}{\frac{-1}{24}}, {x}^{2}, \frac{1}{2}\right) \]
      6. lower-fma.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{-1}{24}\right)}, {x}^{2}, \frac{1}{2}\right) \]
      7. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      8. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{-1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right) \]
      10. lower-*.f6467.8

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), \color{blue}{x \cdot x}, 0.5\right) \]
    5. Applied rewrites67.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)} \]

    if 0.033000000000000002 < x

    1. Initial program 97.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Applied rewrites99.5%

      \[\leadsto \color{blue}{\frac{\frac{1 - \cos x}{x}}{x}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 75.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 0.033:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1 - \cos x}{x \cdot x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 0.033)
   (fma (fma 0.001388888888888889 (* x x) -0.041666666666666664) (* x x) 0.5)
   (/ (- 1.0 (cos x)) (* x x))))
double code(double x) {
	double tmp;
	if (x <= 0.033) {
		tmp = fma(fma(0.001388888888888889, (x * x), -0.041666666666666664), (x * x), 0.5);
	} else {
		tmp = (1.0 - cos(x)) / (x * x);
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (x <= 0.033)
		tmp = fma(fma(0.001388888888888889, Float64(x * x), -0.041666666666666664), Float64(x * x), 0.5);
	else
		tmp = Float64(Float64(1.0 - cos(x)) / Float64(x * x));
	end
	return tmp
end
code[x_] := If[LessEqual[x, 0.033], N[(N[(0.001388888888888889 * N[(x * x), $MachinePrecision] + -0.041666666666666664), $MachinePrecision] * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision], N[(N[(1.0 - N[Cos[x], $MachinePrecision]), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 0.033:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1 - \cos x}{x \cdot x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.033000000000000002

    1. Initial program 34.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) + \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) \cdot {x}^{2}} + \frac{1}{2} \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}, {x}^{2}, \frac{1}{2}\right)} \]
      4. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \left(\mathsf{neg}\left(\frac{1}{24}\right)\right)}, {x}^{2}, \frac{1}{2}\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} + \color{blue}{\frac{-1}{24}}, {x}^{2}, \frac{1}{2}\right) \]
      6. lower-fma.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{-1}{24}\right)}, {x}^{2}, \frac{1}{2}\right) \]
      7. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      8. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{-1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right) \]
      10. lower-*.f6467.8

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), \color{blue}{x \cdot x}, 0.5\right) \]
    5. Applied rewrites67.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)} \]

    if 0.033000000000000002 < x

    1. Initial program 97.2%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 78.3% accurate, 1.1× speedup?

\[\begin{array}{l} \\ {\left(\mathsf{fma}\left(0.16666666666666666, x \cdot x, 2\right)\right)}^{-1} \end{array} \]
(FPCore (x)
 :precision binary64
 (pow (fma 0.16666666666666666 (* x x) 2.0) -1.0))
double code(double x) {
	return pow(fma(0.16666666666666666, (x * x), 2.0), -1.0);
}
function code(x)
	return fma(0.16666666666666666, Float64(x * x), 2.0) ^ -1.0
end
code[x_] := N[Power[N[(0.16666666666666666 * N[(x * x), $MachinePrecision] + 2.0), $MachinePrecision], -1.0], $MachinePrecision]
\begin{array}{l}

\\
{\left(\mathsf{fma}\left(0.16666666666666666, x \cdot x, 2\right)\right)}^{-1}
\end{array}
Derivation
  1. Initial program 48.0%

    \[\frac{1 - \cos x}{x \cdot x} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    2. lift--.f64N/A

      \[\leadsto \frac{\color{blue}{1 - \cos x}}{x \cdot x} \]
    3. div-subN/A

      \[\leadsto \color{blue}{\frac{1}{x \cdot x} - \frac{\cos x}{x \cdot x}} \]
    4. frac-2negN/A

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

      \[\leadsto \frac{\color{blue}{-1}}{\mathsf{neg}\left(x \cdot x\right)} - \frac{\cos x}{x \cdot x} \]
    6. lift-*.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\color{blue}{x \cdot x}\right)} - \frac{\cos x}{x \cdot x} \]
    7. distribute-rgt-neg-inN/A

      \[\leadsto \frac{-1}{\color{blue}{x \cdot \left(\mathsf{neg}\left(x\right)\right)}} - \frac{\cos x}{x \cdot x} \]
    8. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{-1}{x}}{\mathsf{neg}\left(x\right)}} - \frac{\cos x}{x \cdot x} \]
    9. lift-*.f64N/A

      \[\leadsto \frac{\frac{-1}{x}}{\mathsf{neg}\left(x\right)} - \frac{\cos x}{\color{blue}{x \cdot x}} \]
    10. associate-/r*N/A

      \[\leadsto \frac{\frac{-1}{x}}{\mathsf{neg}\left(x\right)} - \color{blue}{\frac{\frac{\cos x}{x}}{x}} \]
    11. frac-2negN/A

      \[\leadsto \frac{\frac{-1}{x}}{\mathsf{neg}\left(x\right)} - \color{blue}{\frac{\mathsf{neg}\left(\frac{\cos x}{x}\right)}{\mathsf{neg}\left(x\right)}} \]
    12. sub-divN/A

      \[\leadsto \color{blue}{\frac{\frac{-1}{x} - \left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}{\mathsf{neg}\left(x\right)}} \]
    13. frac-2negN/A

      \[\leadsto \frac{\color{blue}{\frac{\mathsf{neg}\left(-1\right)}{\mathsf{neg}\left(x\right)}} - \left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}{\mathsf{neg}\left(x\right)} \]
    14. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{1}}{\mathsf{neg}\left(x\right)} - \left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}{\mathsf{neg}\left(x\right)} \]
    15. inv-powN/A

      \[\leadsto \frac{\color{blue}{{\left(\mathsf{neg}\left(x\right)\right)}^{-1}} - \left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}{\mathsf{neg}\left(x\right)} \]
    16. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{{\left(\mathsf{neg}\left(x\right)\right)}^{-1} - \left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}{\mathsf{neg}\left(x\right)}} \]
  4. Applied rewrites49.4%

    \[\leadsto \color{blue}{\frac{\frac{-1}{x} - \left(-\frac{\cos x}{x}\right)}{-x}} \]
  5. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{-1}{x} - \left(-\frac{\cos x}{x}\right)}{-x}} \]
    2. lift-neg.f64N/A

      \[\leadsto \frac{\frac{-1}{x} - \left(-\frac{\cos x}{x}\right)}{\color{blue}{\mathsf{neg}\left(x\right)}} \]
    3. lift--.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{-1}{x} - \left(-\frac{\cos x}{x}\right)}}{\mathsf{neg}\left(x\right)} \]
    4. lift-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{-1}{x}} - \left(-\frac{\cos x}{x}\right)}{\mathsf{neg}\left(x\right)} \]
    5. div-invN/A

      \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1}{x}} - \left(-\frac{\cos x}{x}\right)}{\mathsf{neg}\left(x\right)} \]
    6. lift-neg.f64N/A

      \[\leadsto \frac{-1 \cdot \frac{1}{x} - \color{blue}{\left(\mathsf{neg}\left(\frac{\cos x}{x}\right)\right)}}{\mathsf{neg}\left(x\right)} \]
    7. neg-mul-1N/A

      \[\leadsto \frac{-1 \cdot \frac{1}{x} - \color{blue}{-1 \cdot \frac{\cos x}{x}}}{\mathsf{neg}\left(x\right)} \]
    8. distribute-lft-out--N/A

      \[\leadsto \frac{\color{blue}{-1 \cdot \left(\frac{1}{x} - \frac{\cos x}{x}\right)}}{\mathsf{neg}\left(x\right)} \]
    9. lift-/.f64N/A

      \[\leadsto \frac{-1 \cdot \left(\frac{1}{x} - \color{blue}{\frac{\cos x}{x}}\right)}{\mathsf{neg}\left(x\right)} \]
    10. div-subN/A

      \[\leadsto \frac{-1 \cdot \color{blue}{\frac{1 - \cos x}{x}}}{\mathsf{neg}\left(x\right)} \]
    11. lift-cos.f64N/A

      \[\leadsto \frac{-1 \cdot \frac{1 - \color{blue}{\cos x}}{x}}{\mathsf{neg}\left(x\right)} \]
    12. neg-mul-1N/A

      \[\leadsto \frac{-1 \cdot \frac{1 - \cos x}{x}}{\color{blue}{-1 \cdot x}} \]
    13. times-fracN/A

      \[\leadsto \color{blue}{\frac{-1}{-1} \cdot \frac{\frac{1 - \cos x}{x}}{x}} \]
    14. associate-/r*N/A

      \[\leadsto \frac{-1}{-1} \cdot \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    15. lift-*.f64N/A

      \[\leadsto \frac{-1}{-1} \cdot \frac{1 - \cos x}{\color{blue}{x \cdot x}} \]
    16. times-fracN/A

      \[\leadsto \color{blue}{\frac{-1 \cdot \left(1 - \cos x\right)}{-1 \cdot \left(x \cdot x\right)}} \]
    17. neg-mul-1N/A

      \[\leadsto \frac{\color{blue}{\mathsf{neg}\left(\left(1 - \cos x\right)\right)}}{-1 \cdot \left(x \cdot x\right)} \]
    18. neg-mul-1N/A

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

      \[\leadsto \color{blue}{\frac{1 - \cos x}{x \cdot x}} \]
    20. lift-*.f64N/A

      \[\leadsto \frac{1 - \cos x}{\color{blue}{x \cdot x}} \]
  6. Applied rewrites48.4%

    \[\leadsto \color{blue}{\frac{1}{\frac{x}{\frac{1 - \cos x}{x}}}} \]
  7. Taylor expanded in x around 0

    \[\leadsto \frac{1}{\color{blue}{2 + \frac{1}{6} \cdot {x}^{2}}} \]
  8. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{\frac{1}{6} \cdot {x}^{2} + 2}} \]
    2. lower-fma.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{6}, {x}^{2}, 2\right)}} \]
    3. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\frac{1}{6}, \color{blue}{x \cdot x}, 2\right)} \]
    4. lower-*.f6478.7

      \[\leadsto \frac{1}{\mathsf{fma}\left(0.16666666666666666, \color{blue}{x \cdot x}, 2\right)} \]
  9. Applied rewrites78.7%

    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(0.16666666666666666, x \cdot x, 2\right)}} \]
  10. Final simplification78.7%

    \[\leadsto {\left(\mathsf{fma}\left(0.16666666666666666, x \cdot x, 2\right)\right)}^{-1} \]
  11. Add Preprocessing

Alternative 8: 63.7% accurate, 4.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 4.2 \cdot 10^{+38}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1 - 1}{x \cdot x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 4.2e+38)
   (fma (fma 0.001388888888888889 (* x x) -0.041666666666666664) (* x x) 0.5)
   (/ (- 1.0 1.0) (* x x))))
double code(double x) {
	double tmp;
	if (x <= 4.2e+38) {
		tmp = fma(fma(0.001388888888888889, (x * x), -0.041666666666666664), (x * x), 0.5);
	} else {
		tmp = (1.0 - 1.0) / (x * x);
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (x <= 4.2e+38)
		tmp = fma(fma(0.001388888888888889, Float64(x * x), -0.041666666666666664), Float64(x * x), 0.5);
	else
		tmp = Float64(Float64(1.0 - 1.0) / Float64(x * x));
	end
	return tmp
end
code[x_] := If[LessEqual[x, 4.2e+38], N[(N[(0.001388888888888889 * N[(x * x), $MachinePrecision] + -0.041666666666666664), $MachinePrecision] * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision], N[(N[(1.0 - 1.0), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 4.2 \cdot 10^{+38}:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1 - 1}{x \cdot x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 4.2e38

    1. Initial program 36.4%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) + \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}\right) \cdot {x}^{2}} + \frac{1}{2} \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} - \frac{1}{24}, {x}^{2}, \frac{1}{2}\right)} \]
      4. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \left(\mathsf{neg}\left(\frac{1}{24}\right)\right)}, {x}^{2}, \frac{1}{2}\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2} + \color{blue}{\frac{-1}{24}}, {x}^{2}, \frac{1}{2}\right) \]
      6. lower-fma.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{-1}{24}\right)}, {x}^{2}, \frac{1}{2}\right) \]
      7. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      8. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{-1}{24}\right), {x}^{2}, \frac{1}{2}\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{-1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right) \]
      10. lower-*.f6465.8

        \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), \color{blue}{x \cdot x}, 0.5\right) \]
    5. Applied rewrites65.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, -0.041666666666666664\right), x \cdot x, 0.5\right)} \]

    if 4.2e38 < x

    1. Initial program 96.9%

      \[\frac{1 - \cos x}{x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \frac{1 - \color{blue}{1}}{x \cdot x} \]
    4. Step-by-step derivation
      1. Applied rewrites57.4%

        \[\leadsto \frac{1 - \color{blue}{1}}{x \cdot x} \]
    5. Recombined 2 regimes into one program.
    6. Add Preprocessing

    Alternative 9: 63.9% accurate, 4.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 1.3 \cdot 10^{+77}:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{1 - 1}{x \cdot x}\\ \end{array} \end{array} \]
    (FPCore (x)
     :precision binary64
     (if (<= x 1.3e+77) 0.5 (/ (- 1.0 1.0) (* x x))))
    double code(double x) {
    	double tmp;
    	if (x <= 1.3e+77) {
    		tmp = 0.5;
    	} else {
    		tmp = (1.0 - 1.0) / (x * x);
    	}
    	return tmp;
    }
    
    real(8) function code(x)
        real(8), intent (in) :: x
        real(8) :: tmp
        if (x <= 1.3d+77) then
            tmp = 0.5d0
        else
            tmp = (1.0d0 - 1.0d0) / (x * x)
        end if
        code = tmp
    end function
    
    public static double code(double x) {
    	double tmp;
    	if (x <= 1.3e+77) {
    		tmp = 0.5;
    	} else {
    		tmp = (1.0 - 1.0) / (x * x);
    	}
    	return tmp;
    }
    
    def code(x):
    	tmp = 0
    	if x <= 1.3e+77:
    		tmp = 0.5
    	else:
    		tmp = (1.0 - 1.0) / (x * x)
    	return tmp
    
    function code(x)
    	tmp = 0.0
    	if (x <= 1.3e+77)
    		tmp = 0.5;
    	else
    		tmp = Float64(Float64(1.0 - 1.0) / Float64(x * x));
    	end
    	return tmp
    end
    
    function tmp_2 = code(x)
    	tmp = 0.0;
    	if (x <= 1.3e+77)
    		tmp = 0.5;
    	else
    		tmp = (1.0 - 1.0) / (x * x);
    	end
    	tmp_2 = tmp;
    end
    
    code[x_] := If[LessEqual[x, 1.3e+77], 0.5, N[(N[(1.0 - 1.0), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;x \leq 1.3 \cdot 10^{+77}:\\
    \;\;\;\;0.5\\
    
    \mathbf{else}:\\
    \;\;\;\;\frac{1 - 1}{x \cdot x}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if x < 1.3000000000000001e77

      1. Initial program 37.6%

        \[\frac{1 - \cos x}{x \cdot x} \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \color{blue}{\frac{1}{2}} \]
      4. Step-by-step derivation
        1. Applied rewrites65.0%

          \[\leadsto \color{blue}{0.5} \]

        if 1.3000000000000001e77 < x

        1. Initial program 96.7%

          \[\frac{1 - \cos x}{x \cdot x} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \frac{1 - \color{blue}{1}}{x \cdot x} \]
        4. Step-by-step derivation
          1. Applied rewrites62.2%

            \[\leadsto \frac{1 - \color{blue}{1}}{x \cdot x} \]
        5. Recombined 2 regimes into one program.
        6. Add Preprocessing

        Alternative 10: 52.0% accurate, 120.0× speedup?

        \[\begin{array}{l} \\ 0.5 \end{array} \]
        (FPCore (x) :precision binary64 0.5)
        double code(double x) {
        	return 0.5;
        }
        
        real(8) function code(x)
            real(8), intent (in) :: x
            code = 0.5d0
        end function
        
        public static double code(double x) {
        	return 0.5;
        }
        
        def code(x):
        	return 0.5
        
        function code(x)
        	return 0.5
        end
        
        function tmp = code(x)
        	tmp = 0.5;
        end
        
        code[x_] := 0.5
        
        \begin{array}{l}
        
        \\
        0.5
        \end{array}
        
        Derivation
        1. Initial program 48.0%

          \[\frac{1 - \cos x}{x \cdot x} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{\frac{1}{2}} \]
        4. Step-by-step derivation
          1. Applied rewrites54.2%

            \[\leadsto \color{blue}{0.5} \]
          2. Add Preprocessing

          Reproduce

          ?
          herbie shell --seed 2024313 
          (FPCore (x)
            :name "cos2 (problem 3.4.1)"
            :precision binary64
            (/ (- 1.0 (cos x)) (* x x)))