Falkner and Boettcher, Equation (22+)

Percentage Accurate: 98.5% → 100.0%
Time: 2.3s
Alternatives: 5
Speedup: 3.2×

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}

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 5 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, 1.1× speedup?

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

\\
\frac{\frac{-1.3333333333333333}{\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}}{\pi}
\end{array}
Derivation
  1. Initial program 98.5%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    3. lift-*.f64N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    6. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    7. lift-*.f64N/A

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

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    10. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3}}}{\pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    11. *-commutativeN/A

      \[\leadsto \frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
    12. lower-*.f64100.0

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
  3. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
  4. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\frac{4}{3}}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    2. mult-flipN/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi}} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)} \]
    4. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}}{\pi}} \]
    5. mult-flip-revN/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}}}{\pi} \]
    6. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3} \cdot 1}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}}{\pi} \]
    7. lift-*.f64N/A

      \[\leadsto \frac{\frac{\frac{4}{3} \cdot 1}{\color{blue}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}}}{\pi} \]
    8. *-commutativeN/A

      \[\leadsto \frac{\frac{\frac{4}{3} \cdot 1}{\color{blue}{\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}}{\pi} \]
    9. frac-timesN/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{1 - v \cdot v} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}}{\pi} \]
    10. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\mathsf{neg}\left(\frac{-4}{3}\right)}}{1 - v \cdot v} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    11. lift--.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\color{blue}{1 - v \cdot v}} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    12. sub-negate-revN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\color{blue}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    13. metadata-evalN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\left(v \cdot v - \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)}\right)\right)} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    14. add-flipN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\color{blue}{\left(v \cdot v + -1\right)}\right)} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    15. lift-*.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\left(\color{blue}{v \cdot v} + -1\right)\right)} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    16. lift-fma.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\color{blue}{\mathsf{fma}\left(v, v, -1\right)}\right)} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
    17. frac-2negN/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{-4}{3}}{\mathsf{fma}\left(v, v, -1\right)}} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\pi} \]
  5. Applied rewrites100.0%

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

Alternative 2: 100.0% accurate, 1.2× speedup?

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

\\
\frac{-1.3333333333333333}{\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right) \cdot \pi}
\end{array}
Derivation
  1. Initial program 98.5%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    3. lift-*.f64N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    6. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    7. lift-*.f64N/A

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

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    10. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3}}}{\pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    11. *-commutativeN/A

      \[\leadsto \frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
    12. lower-*.f64100.0

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
  3. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
  4. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\frac{4}{3}}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    2. mult-flipN/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. *-commutativeN/A

      \[\leadsto \color{blue}{\frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)} \cdot \frac{\frac{4}{3}}{\pi}} \]
    4. frac-2negN/A

      \[\leadsto \color{blue}{\frac{\mathsf{neg}\left(1\right)}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)}} \cdot \frac{\frac{4}{3}}{\pi} \]
    5. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{-1}}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)} \cdot \frac{\frac{4}{3}}{\pi} \]
    6. lift-/.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)} \cdot \color{blue}{\frac{\frac{4}{3}}{\pi}} \]
    7. frac-timesN/A

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{4}{3}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
    8. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{\frac{-4}{3}}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi} \]
    9. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{-4}{3}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
    10. lower-*.f64N/A

      \[\leadsto \frac{\frac{-4}{3}}{\color{blue}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
  5. Applied rewrites100.0%

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

Alternative 3: 99.1% accurate, 1.7× speedup?

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

\\
\frac{1.3333333333333333}{\pi \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}
\end{array}
Derivation
  1. Initial program 98.5%

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    3. lift-*.f64N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    6. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    7. lift-*.f64N/A

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

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    10. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3}}}{\pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    11. *-commutativeN/A

      \[\leadsto \frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
    12. lower-*.f64100.0

      \[\leadsto \frac{\frac{1.3333333333333333}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
  3. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
  4. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\frac{4}{3}}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    2. mult-flipN/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi}} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)} \]
    4. lift-*.f64N/A

      \[\leadsto \frac{\frac{4}{3}}{\pi} \cdot \frac{1}{\color{blue}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    5. *-commutativeN/A

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

      \[\leadsto \frac{\frac{4}{3}}{\pi} \cdot \color{blue}{\frac{\frac{1}{1 - v \cdot v}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}} \]
    7. frac-timesN/A

      \[\leadsto \color{blue}{\frac{\frac{4}{3} \cdot \frac{1}{1 - v \cdot v}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}} \]
    8. mult-flipN/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{1 - v \cdot v}}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    9. metadata-evalN/A

      \[\leadsto \frac{\frac{\color{blue}{\mathsf{neg}\left(\frac{-4}{3}\right)}}{1 - v \cdot v}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    10. lift--.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\color{blue}{1 - v \cdot v}}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    11. sub-negate-revN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\color{blue}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    12. metadata-evalN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\left(v \cdot v - \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)}\right)\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    13. add-flipN/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\color{blue}{\left(v \cdot v + -1\right)}\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    14. lift-*.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\left(\color{blue}{v \cdot v} + -1\right)\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    15. lift-fma.f64N/A

      \[\leadsto \frac{\frac{\mathsf{neg}\left(\frac{-4}{3}\right)}{\mathsf{neg}\left(\color{blue}{\mathsf{fma}\left(v, v, -1\right)}\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    16. frac-2negN/A

      \[\leadsto \frac{\color{blue}{\frac{\frac{-4}{3}}{\mathsf{fma}\left(v, v, -1\right)}}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    17. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\frac{-4}{3}}{\mathsf{fma}\left(v, v, -1\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}} \]
  5. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{\frac{-1.3333333333333333}{\mathsf{fma}\left(v, v, -1\right)}}{\pi \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
  6. Taylor expanded in v around 0

    \[\leadsto \frac{\color{blue}{\frac{4}{3}}}{\pi \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
  7. Step-by-step derivation
    1. Applied rewrites99.1%

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

    Alternative 4: 99.0% accurate, 1.7× speedup?

    \[\begin{array}{l} \\ \frac{-1.3333333333333333}{\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{2}\right) \cdot \pi} \end{array} \]
    (FPCore (v)
     :precision binary64
     (/ -1.3333333333333333 (* (* (fma v v -1.0) (sqrt 2.0)) PI)))
    double code(double v) {
    	return -1.3333333333333333 / ((fma(v, v, -1.0) * sqrt(2.0)) * ((double) M_PI));
    }
    
    function code(v)
    	return Float64(-1.3333333333333333 / Float64(Float64(fma(v, v, -1.0) * sqrt(2.0)) * pi))
    end
    
    code[v_] := N[(-1.3333333333333333 / N[(N[(N[(v * v + -1.0), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * Pi), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \frac{-1.3333333333333333}{\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{2}\right) \cdot \pi}
    \end{array}
    
    Derivation
    1. Initial program 98.5%

      \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    2. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
      3. lift-*.f64N/A

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

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

        \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
      6. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{4}{3 \cdot \pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}} \]
      7. lift-*.f64N/A

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

        \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
      9. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{\pi}}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
      10. metadata-evalN/A

        \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3}}}{\pi}}{\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
      11. *-commutativeN/A

        \[\leadsto \frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
      12. lower-*.f64100.0

        \[\leadsto \frac{\frac{1.3333333333333333}{\pi}}{\color{blue}{\sqrt{2 - 6 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{\frac{1.3333333333333333}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
    4. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{\frac{4}{3}}{\pi}}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
      2. mult-flipN/A

        \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\pi} \cdot \frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)}} \]
      3. *-commutativeN/A

        \[\leadsto \color{blue}{\frac{1}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)} \cdot \frac{\frac{4}{3}}{\pi}} \]
      4. frac-2negN/A

        \[\leadsto \color{blue}{\frac{\mathsf{neg}\left(1\right)}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)}} \cdot \frac{\frac{4}{3}}{\pi} \]
      5. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{-1}}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)} \cdot \frac{\frac{4}{3}}{\pi} \]
      6. lift-/.f64N/A

        \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)} \cdot \color{blue}{\frac{\frac{4}{3}}{\pi}} \]
      7. frac-timesN/A

        \[\leadsto \color{blue}{\frac{-1 \cdot \frac{4}{3}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
      8. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{\frac{-4}{3}}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi} \]
      9. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{-4}{3}}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
      10. lower-*.f64N/A

        \[\leadsto \frac{\frac{-4}{3}}{\color{blue}{\left(\mathsf{neg}\left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right) \cdot \pi}} \]
    5. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{-1.3333333333333333}{\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right) \cdot \pi}} \]
    6. Taylor expanded in v around 0

      \[\leadsto \frac{\frac{-4}{3}}{\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{\color{blue}{2}}\right) \cdot \pi} \]
    7. Step-by-step derivation
      1. Applied rewrites99.0%

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

      Alternative 5: 99.0% accurate, 3.2× speedup?

      \[\begin{array}{l} \\ \frac{1.3333333333333333}{\pi \cdot \sqrt{2}} \end{array} \]
      (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(1.3333333333333333 / Float64(pi * sqrt(2.0)))
      end
      
      function tmp = code(v)
      	tmp = 1.3333333333333333 / (pi * sqrt(2.0));
      end
      
      code[v_] := N[(1.3333333333333333 / N[(Pi * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \frac{1.3333333333333333}{\pi \cdot \sqrt{2}}
      \end{array}
      
      Derivation
      1. Initial program 98.5%

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

        \[\leadsto \color{blue}{\frac{\frac{4}{3}}{\mathsf{PI}\left(\right) \cdot \sqrt{2}}} \]
      3. Step-by-step derivation
        1. lower-/.f64N/A

          \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\mathsf{PI}\left(\right) \cdot \sqrt{2}}} \]
        2. lower-*.f64N/A

          \[\leadsto \frac{\frac{4}{3}}{\mathsf{PI}\left(\right) \cdot \color{blue}{\sqrt{2}}} \]
        3. lower-PI.f64N/A

          \[\leadsto \frac{\frac{4}{3}}{\pi \cdot \sqrt{\color{blue}{2}}} \]
        4. lower-sqrt.f6499.0

          \[\leadsto \frac{1.3333333333333333}{\pi \cdot \sqrt{2}} \]
      4. Applied rewrites99.0%

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

      Reproduce

      ?
      herbie shell --seed 2025162 
      (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)))))))