Falkner and Boettcher, Equation (22+)

Percentage Accurate: 98.5% → 100.0%
Time: 5.7s
Alternatives: 6
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ \frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (* (* 3.0 PI) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))
double code(double v) {
	return 4.0 / (((3.0 * ((double) M_PI)) * (1.0 - (v * v))) * sqrt((2.0 - (6.0 * (v * v)))));
}
public static double code(double v) {
	return 4.0 / (((3.0 * Math.PI) * (1.0 - (v * v))) * Math.sqrt((2.0 - (6.0 * (v * v)))));
}
def code(v):
	return 4.0 / (((3.0 * math.pi) * (1.0 - (v * v))) * math.sqrt((2.0 - (6.0 * (v * v)))))
function code(v)
	return Float64(4.0 / Float64(Float64(Float64(3.0 * pi) * Float64(1.0 - Float64(v * v))) * sqrt(Float64(2.0 - Float64(6.0 * Float64(v * v))))))
end
function tmp = code(v)
	tmp = 4.0 / (((3.0 * pi) * (1.0 - (v * v))) * sqrt((2.0 - (6.0 * (v * v)))));
end
code[v_] := N[(4.0 / N[(N[(N[(3.0 * Pi), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(2.0 - N[(6.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}
\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 6 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: 98.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (* (* 3.0 PI) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))
double code(double v) {
	return 4.0 / (((3.0 * ((double) M_PI)) * (1.0 - (v * v))) * sqrt((2.0 - (6.0 * (v * v)))));
}
public static double code(double v) {
	return 4.0 / (((3.0 * Math.PI) * (1.0 - (v * v))) * Math.sqrt((2.0 - (6.0 * (v * v)))));
}
def code(v):
	return 4.0 / (((3.0 * math.pi) * (1.0 - (v * v))) * math.sqrt((2.0 - (6.0 * (v * v)))))
function code(v)
	return Float64(4.0 / Float64(Float64(Float64(3.0 * pi) * Float64(1.0 - Float64(v * v))) * sqrt(Float64(2.0 - Float64(6.0 * Float64(v * v))))))
end
function tmp = code(v)
	tmp = 4.0 / (((3.0 * pi) * (1.0 - (v * v))) * sqrt((2.0 - (6.0 * (v * v)))));
end
code[v_] := N[(4.0 / N[(N[(N[(3.0 * Pi), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(2.0 - N[(6.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}
\end{array}

Alternative 1: 100.0% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \frac{\frac{\frac{1}{\pi} \cdot 1.3333333333333333}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/
  (/ (* (/ 1.0 PI) 1.3333333333333333) (- 1.0 (* v v)))
  (sqrt (fma (* v v) -6.0 2.0))))
double code(double v) {
	return (((1.0 / ((double) M_PI)) * 1.3333333333333333) / (1.0 - (v * v))) / sqrt(fma((v * v), -6.0, 2.0));
}
function code(v)
	return Float64(Float64(Float64(Float64(1.0 / pi) * 1.3333333333333333) / Float64(1.0 - Float64(v * v))) / sqrt(fma(Float64(v * v), -6.0, 2.0)))
end
code[v_] := N[(N[(N[(N[(1.0 / Pi), $MachinePrecision] * 1.3333333333333333), $MachinePrecision] / N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Sqrt[N[(N[(v * v), $MachinePrecision] * -6.0 + 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{\frac{1}{\pi} \cdot 1.3333333333333333}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. associate-/r*100.0%

      \[\leadsto \color{blue}{\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \color{blue}{\left(-v\right) \cdot \left(-v\right)}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    3. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}}} \]
    4. remove-double-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\color{blue}{-\left(-\sqrt{2 - 6 \cdot \left(\left(-v\right) \cdot \left(-v\right)\right)}\right)}} \]
    5. distribute-neg-frac2100.0%

      \[\leadsto \color{blue}{-\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{-\sqrt{2 - 6 \cdot \left(\left(-v\right) \cdot \left(-v\right)\right)}}} \]
    6. distribute-neg-frac2100.0%

      \[\leadsto -\color{blue}{\left(-\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(\left(-v\right) \cdot \left(-v\right)\right)}}\right)} \]
    7. distribute-neg-frac100.0%

      \[\leadsto -\color{blue}{\frac{-\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(\left(-v\right) \cdot \left(-v\right)\right)}}} \]
    8. distribute-frac-neg100.0%

      \[\leadsto \color{blue}{\frac{-\left(-\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}\right)}{\sqrt{2 - 6 \cdot \left(\left(-v\right) \cdot \left(-v\right)\right)}}} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\frac{\frac{\frac{1.3333333333333333}{\pi}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. clear-num100.0%

      \[\leadsto \frac{\frac{\color{blue}{\frac{1}{\frac{\pi}{1.3333333333333333}}}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
    2. associate-/r/100.0%

      \[\leadsto \frac{\frac{\color{blue}{\frac{1}{\pi} \cdot 1.3333333333333333}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
  6. Applied egg-rr100.0%

    \[\leadsto \frac{\frac{\color{blue}{\frac{1}{\pi} \cdot 1.3333333333333333}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
  7. Add Preprocessing

Alternative 2: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/
  (/ 1.3333333333333333 (* PI (- 1.0 (* v v))))
  (sqrt (+ 2.0 (* (* v v) -6.0)))))
double code(double v) {
	return (1.3333333333333333 / (((double) M_PI) * (1.0 - (v * v)))) / sqrt((2.0 + ((v * v) * -6.0)));
}
public static double code(double v) {
	return (1.3333333333333333 / (Math.PI * (1.0 - (v * v)))) / Math.sqrt((2.0 + ((v * v) * -6.0)));
}
def code(v):
	return (1.3333333333333333 / (math.pi * (1.0 - (v * v)))) / math.sqrt((2.0 + ((v * v) * -6.0)))
function code(v)
	return Float64(Float64(1.3333333333333333 / Float64(pi * Float64(1.0 - Float64(v * v)))) / sqrt(Float64(2.0 + Float64(Float64(v * v) * -6.0))))
end
function tmp = code(v)
	tmp = (1.3333333333333333 / (pi * (1.0 - (v * v)))) / sqrt((2.0 + ((v * v) * -6.0)));
end
code[v_] := N[(N[(1.3333333333333333 / N[(Pi * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Sqrt[N[(2.0 + N[(N[(v * v), $MachinePrecision] * -6.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. associate-/r*100.0%

      \[\leadsto \color{blue}{\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \color{blue}{\left(-v\right) \cdot \left(-v\right)}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    3. associate-*l*100.0%

      \[\leadsto \frac{\frac{4}{\color{blue}{3 \cdot \left(\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    4. associate-/r*100.0%

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    5. metadata-eval100.0%

      \[\leadsto \frac{\frac{\color{blue}{1.3333333333333333}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    6. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - \color{blue}{v \cdot v}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    7. sub-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{\color{blue}{2 + \left(-6 \cdot \left(v \cdot v\right)\right)}}} \]
    8. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-6 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right)}} \]
    9. *-commutative100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 6}\right)}} \]
    10. distribute-rgt-neg-in100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-6\right)}}} \]
    11. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(v \cdot v\right)} \cdot \left(-6\right)}} \]
    12. metadata-eval100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot \color{blue}{-6}}} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}} \]
  4. Add Preprocessing
  5. Add Preprocessing

Alternative 3: 99.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{\frac{1}{\pi} \cdot 1.3333333333333333}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ (* (/ 1.0 PI) 1.3333333333333333) (sqrt (+ 2.0 (* (* v v) -6.0)))))
double code(double v) {
	return ((1.0 / ((double) M_PI)) * 1.3333333333333333) / sqrt((2.0 + ((v * v) * -6.0)));
}
public static double code(double v) {
	return ((1.0 / Math.PI) * 1.3333333333333333) / Math.sqrt((2.0 + ((v * v) * -6.0)));
}
def code(v):
	return ((1.0 / math.pi) * 1.3333333333333333) / math.sqrt((2.0 + ((v * v) * -6.0)))
function code(v)
	return Float64(Float64(Float64(1.0 / pi) * 1.3333333333333333) / sqrt(Float64(2.0 + Float64(Float64(v * v) * -6.0))))
end
function tmp = code(v)
	tmp = ((1.0 / pi) * 1.3333333333333333) / sqrt((2.0 + ((v * v) * -6.0)));
end
code[v_] := N[(N[(N[(1.0 / Pi), $MachinePrecision] * 1.3333333333333333), $MachinePrecision] / N[Sqrt[N[(2.0 + N[(N[(v * v), $MachinePrecision] * -6.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{1}{\pi} \cdot 1.3333333333333333}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. associate-/r*100.0%

      \[\leadsto \color{blue}{\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \color{blue}{\left(-v\right) \cdot \left(-v\right)}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    3. associate-*l*100.0%

      \[\leadsto \frac{\frac{4}{\color{blue}{3 \cdot \left(\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    4. associate-/r*100.0%

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    5. metadata-eval100.0%

      \[\leadsto \frac{\frac{\color{blue}{1.3333333333333333}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    6. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - \color{blue}{v \cdot v}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    7. sub-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{\color{blue}{2 + \left(-6 \cdot \left(v \cdot v\right)\right)}}} \]
    8. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-6 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right)}} \]
    9. *-commutative100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 6}\right)}} \]
    10. distribute-rgt-neg-in100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-6\right)}}} \]
    11. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(v \cdot v\right)} \cdot \left(-6\right)}} \]
    12. metadata-eval100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot \color{blue}{-6}}} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0 99.1%

    \[\leadsto \frac{\color{blue}{\frac{1.3333333333333333}{\pi}}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \]
  6. Step-by-step derivation
    1. clear-num100.0%

      \[\leadsto \frac{\frac{\color{blue}{\frac{1}{\frac{\pi}{1.3333333333333333}}}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
    2. associate-/r/100.0%

      \[\leadsto \frac{\frac{\color{blue}{\frac{1}{\pi} \cdot 1.3333333333333333}}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
  7. Applied egg-rr99.1%

    \[\leadsto \frac{\color{blue}{\frac{1}{\pi} \cdot 1.3333333333333333}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \]
  8. Add Preprocessing

Alternative 4: 99.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{\frac{1.3333333333333333}{\pi}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ (/ 1.3333333333333333 PI) (sqrt (+ 2.0 (* (* v v) -6.0)))))
double code(double v) {
	return (1.3333333333333333 / ((double) M_PI)) / sqrt((2.0 + ((v * v) * -6.0)));
}
public static double code(double v) {
	return (1.3333333333333333 / Math.PI) / Math.sqrt((2.0 + ((v * v) * -6.0)));
}
def code(v):
	return (1.3333333333333333 / math.pi) / math.sqrt((2.0 + ((v * v) * -6.0)))
function code(v)
	return Float64(Float64(1.3333333333333333 / pi) / sqrt(Float64(2.0 + Float64(Float64(v * v) * -6.0))))
end
function tmp = code(v)
	tmp = (1.3333333333333333 / pi) / sqrt((2.0 + ((v * v) * -6.0)));
end
code[v_] := N[(N[(1.3333333333333333 / Pi), $MachinePrecision] / N[Sqrt[N[(2.0 + N[(N[(v * v), $MachinePrecision] * -6.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. associate-/r*100.0%

      \[\leadsto \color{blue}{\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \color{blue}{\left(-v\right) \cdot \left(-v\right)}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    3. associate-*l*100.0%

      \[\leadsto \frac{\frac{4}{\color{blue}{3 \cdot \left(\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    4. associate-/r*100.0%

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    5. metadata-eval100.0%

      \[\leadsto \frac{\frac{\color{blue}{1.3333333333333333}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    6. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - \color{blue}{v \cdot v}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    7. sub-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{\color{blue}{2 + \left(-6 \cdot \left(v \cdot v\right)\right)}}} \]
    8. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-6 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right)}} \]
    9. *-commutative100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 6}\right)}} \]
    10. distribute-rgt-neg-in100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-6\right)}}} \]
    11. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(v \cdot v\right)} \cdot \left(-6\right)}} \]
    12. metadata-eval100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot \color{blue}{-6}}} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0 99.1%

    \[\leadsto \frac{\color{blue}{\frac{1.3333333333333333}{\pi}}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \]
  6. Add Preprocessing

Alternative 5: 99.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{\frac{1.3333333333333333}{\pi}}{\sqrt{2}} \end{array} \]
(FPCore (v) :precision binary64 (/ (/ 1.3333333333333333 PI) (sqrt 2.0)))
double code(double v) {
	return (1.3333333333333333 / ((double) M_PI)) / sqrt(2.0);
}
public static double code(double v) {
	return (1.3333333333333333 / Math.PI) / Math.sqrt(2.0);
}
def code(v):
	return (1.3333333333333333 / math.pi) / math.sqrt(2.0)
function code(v)
	return Float64(Float64(1.3333333333333333 / pi) / sqrt(2.0))
end
function tmp = code(v)
	tmp = (1.3333333333333333 / pi) / sqrt(2.0);
end
code[v_] := N[(N[(1.3333333333333333 / Pi), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{2}}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. associate-/r*100.0%

      \[\leadsto \color{blue}{\frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. sqr-neg100.0%

      \[\leadsto \frac{\frac{4}{\left(3 \cdot \pi\right) \cdot \left(1 - \color{blue}{\left(-v\right) \cdot \left(-v\right)}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    3. associate-*l*100.0%

      \[\leadsto \frac{\frac{4}{\color{blue}{3 \cdot \left(\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    4. associate-/r*100.0%

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    5. metadata-eval100.0%

      \[\leadsto \frac{\frac{\color{blue}{1.3333333333333333}}{\pi \cdot \left(1 - \left(-v\right) \cdot \left(-v\right)\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    6. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - \color{blue}{v \cdot v}\right)}}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    7. sub-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{\color{blue}{2 + \left(-6 \cdot \left(v \cdot v\right)\right)}}} \]
    8. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-6 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right)}} \]
    9. *-commutative100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 6}\right)}} \]
    10. distribute-rgt-neg-in100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-6\right)}}} \]
    11. sqr-neg100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \color{blue}{\left(v \cdot v\right)} \cdot \left(-6\right)}} \]
    12. metadata-eval100.0%

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot \color{blue}{-6}}} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi \cdot \left(1 - v \cdot v\right)}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}}} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0 99.1%

    \[\leadsto \frac{\color{blue}{\frac{1.3333333333333333}{\pi}}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6}} \]
  6. Taylor expanded in v around 0 99.1%

    \[\leadsto \frac{\frac{1.3333333333333333}{\pi}}{\color{blue}{\sqrt{2}}} \]
  7. Add Preprocessing

Alternative 6: 97.5% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{\sqrt{0.8888888888888888}}{\pi} \end{array} \]
(FPCore (v) :precision binary64 (/ (sqrt 0.8888888888888888) PI))
double code(double v) {
	return sqrt(0.8888888888888888) / ((double) M_PI);
}
public static double code(double v) {
	return Math.sqrt(0.8888888888888888) / Math.PI;
}
def code(v):
	return math.sqrt(0.8888888888888888) / math.pi
function code(v)
	return Float64(sqrt(0.8888888888888888) / pi)
end
function tmp = code(v)
	tmp = sqrt(0.8888888888888888) / pi;
end
code[v_] := N[(N[Sqrt[0.8888888888888888], $MachinePrecision] / Pi), $MachinePrecision]
\begin{array}{l}

\\
\frac{\sqrt{0.8888888888888888}}{\pi}
\end{array}
Derivation
  1. Initial program 98.4%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Add Preprocessing
  3. Taylor expanded in v around 0 97.6%

    \[\leadsto \color{blue}{1.3333333333333333 \cdot \frac{\sqrt{0.5}}{\pi}} \]
  4. Step-by-step derivation
    1. *-commutative97.6%

      \[\leadsto \color{blue}{\frac{\sqrt{0.5}}{\pi} \cdot 1.3333333333333333} \]
    2. associate-*l/97.6%

      \[\leadsto \color{blue}{\frac{\sqrt{0.5} \cdot 1.3333333333333333}{\pi}} \]
  5. Simplified97.6%

    \[\leadsto \color{blue}{\frac{\sqrt{0.5} \cdot 1.3333333333333333}{\pi}} \]
  6. Step-by-step derivation
    1. div-inv97.6%

      \[\leadsto \color{blue}{\left(\sqrt{0.5} \cdot 1.3333333333333333\right) \cdot \frac{1}{\pi}} \]
    2. add-sqr-sqrt97.6%

      \[\leadsto \color{blue}{\left(\sqrt{\sqrt{0.5} \cdot 1.3333333333333333} \cdot \sqrt{\sqrt{0.5} \cdot 1.3333333333333333}\right)} \cdot \frac{1}{\pi} \]
    3. sqrt-unprod97.6%

      \[\leadsto \color{blue}{\sqrt{\left(\sqrt{0.5} \cdot 1.3333333333333333\right) \cdot \left(\sqrt{0.5} \cdot 1.3333333333333333\right)}} \cdot \frac{1}{\pi} \]
    4. swap-sqr97.6%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{0.5} \cdot \sqrt{0.5}\right) \cdot \left(1.3333333333333333 \cdot 1.3333333333333333\right)}} \cdot \frac{1}{\pi} \]
    5. rem-square-sqrt97.6%

      \[\leadsto \sqrt{\color{blue}{0.5} \cdot \left(1.3333333333333333 \cdot 1.3333333333333333\right)} \cdot \frac{1}{\pi} \]
    6. metadata-eval97.6%

      \[\leadsto \sqrt{0.5 \cdot \color{blue}{1.7777777777777777}} \cdot \frac{1}{\pi} \]
    7. metadata-eval97.6%

      \[\leadsto \sqrt{\color{blue}{0.8888888888888888}} \cdot \frac{1}{\pi} \]
  7. Applied egg-rr97.6%

    \[\leadsto \color{blue}{\sqrt{0.8888888888888888} \cdot \frac{1}{\pi}} \]
  8. Step-by-step derivation
    1. associate-*r/97.6%

      \[\leadsto \color{blue}{\frac{\sqrt{0.8888888888888888} \cdot 1}{\pi}} \]
    2. *-rgt-identity97.6%

      \[\leadsto \frac{\color{blue}{\sqrt{0.8888888888888888}}}{\pi} \]
  9. Simplified97.6%

    \[\leadsto \color{blue}{\frac{\sqrt{0.8888888888888888}}{\pi}} \]
  10. Add Preprocessing

Reproduce

?
herbie shell --seed 2024181 
(FPCore (v)
  :name "Falkner and Boettcher, Equation (22+)"
  :precision binary64
  (/ 4.0 (* (* (* 3.0 PI) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))