Falkner and Boettcher, Appendix B, 2

Percentage Accurate: 100.0% → 100.0%
Time: 11.8s
Alternatives: 3
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))
double code(double v) {
	return ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = ((sqrt(2.0d0) / 4.0d0) * sqrt((1.0d0 - (3.0d0 * (v * v))))) * (1.0d0 - (v * v))
end function
public static double code(double v) {
	return ((Math.sqrt(2.0) / 4.0) * Math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
def code(v):
	return ((math.sqrt(2.0) / 4.0) * math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v))
function code(v)
	return Float64(Float64(Float64(sqrt(2.0) / 4.0) * sqrt(Float64(1.0 - Float64(3.0 * Float64(v * v))))) * Float64(1.0 - Float64(v * v)))
end
function tmp = code(v)
	tmp = ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
end
code[v_] := N[(N[(N[(N[Sqrt[2.0], $MachinePrecision] / 4.0), $MachinePrecision] * N[Sqrt[N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - 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 3 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: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))
double code(double v) {
	return ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = ((sqrt(2.0d0) / 4.0d0) * sqrt((1.0d0 - (3.0d0 * (v * v))))) * (1.0d0 - (v * v))
end function
public static double code(double v) {
	return ((Math.sqrt(2.0) / 4.0) * Math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
def code(v):
	return ((math.sqrt(2.0) / 4.0) * math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v))
function code(v)
	return Float64(Float64(Float64(sqrt(2.0) / 4.0) * sqrt(Float64(1.0 - Float64(3.0 * Float64(v * v))))) * Float64(1.0 - Float64(v * v)))
end
function tmp = code(v)
	tmp = ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
end
code[v_] := N[(N[(N[(N[Sqrt[2.0], $MachinePrecision] / 4.0), $MachinePrecision] * N[Sqrt[N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

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

Alternative 1: 100.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \left(1 - v \cdot v\right) \cdot \left(\sqrt{2 + \left(v \cdot v\right) \cdot -6} \cdot 0.25\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (* (- 1.0 (* v v)) (* (sqrt (+ 2.0 (* (* v v) -6.0))) 0.25)))
double code(double v) {
	return (1.0 - (v * v)) * (sqrt((2.0 + ((v * v) * -6.0))) * 0.25);
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = (1.0d0 - (v * v)) * (sqrt((2.0d0 + ((v * v) * (-6.0d0)))) * 0.25d0)
end function
public static double code(double v) {
	return (1.0 - (v * v)) * (Math.sqrt((2.0 + ((v * v) * -6.0))) * 0.25);
}
def code(v):
	return (1.0 - (v * v)) * (math.sqrt((2.0 + ((v * v) * -6.0))) * 0.25)
function code(v)
	return Float64(Float64(1.0 - Float64(v * v)) * Float64(sqrt(Float64(2.0 + Float64(Float64(v * v) * -6.0))) * 0.25))
end
function tmp = code(v)
	tmp = (1.0 - (v * v)) * (sqrt((2.0 + ((v * v) * -6.0))) * 0.25);
end
code[v_] := N[(N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision] * N[(N[Sqrt[N[(2.0 + N[(N[(v * v), $MachinePrecision] * -6.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 0.25), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(1 - v \cdot v\right) \cdot \left(\sqrt{2 + \left(v \cdot v\right) \cdot -6} \cdot 0.25\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. clear-numN/A

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

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

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

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

      \[\leadsto \left(\frac{\color{blue}{\frac{1}{4}}}{\frac{1}{\sqrt{2}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    6. pow1/2N/A

      \[\leadsto \left(\frac{\frac{1}{4}}{\frac{1}{\color{blue}{{2}^{\frac{1}{2}}}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    7. pow-flipN/A

      \[\leadsto \left(\frac{\frac{1}{4}}{\color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    8. pow-lowering-pow.f64N/A

      \[\leadsto \left(\frac{\frac{1}{4}}{\color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    9. metadata-eval98.5

      \[\leadsto \left(\frac{0.25}{{2}^{\color{blue}{-0.5}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  4. Applied egg-rr98.5%

    \[\leadsto \left(\color{blue}{\frac{0.25}{{2}^{-0.5}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  5. Step-by-step derivation
    1. *-commutativeN/A

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

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

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

      \[\leadsto \left(1 - \color{blue}{v \cdot v}\right) \cdot \left(\frac{\frac{1}{4}}{{2}^{\frac{-1}{2}}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \]
    5. clear-numN/A

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

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\color{blue}{\left(\frac{1}{{2}^{\frac{-1}{2}}} \cdot \frac{1}{4}\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \]
    7. pow-flipN/A

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

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\left({2}^{\color{blue}{\frac{1}{2}}} \cdot \frac{1}{4}\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \]
    9. pow1/2N/A

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

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

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

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

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

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

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{\color{blue}{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}}\right) \]
    16. sub-negN/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \color{blue}{\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)}}\right) \]
    17. +-lowering-+.f64N/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \color{blue}{\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)}}\right) \]
    18. *-commutativeN/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \left(1 + \left(\mathsf{neg}\left(\color{blue}{\left(v \cdot v\right) \cdot 3}\right)\right)\right)}\right) \]
    19. distribute-rgt-neg-inN/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \left(1 + \color{blue}{\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)}\right)}\right) \]
    20. *-lowering-*.f64N/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \left(1 + \color{blue}{\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)}\right)}\right) \]
    21. *-lowering-*.f64N/A

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\frac{1}{4} \cdot \sqrt{2 \cdot \left(1 + \color{blue}{\left(v \cdot v\right)} \cdot \left(\mathsf{neg}\left(3\right)\right)\right)}\right) \]
    22. metadata-eval100.0

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(0.25 \cdot \sqrt{2 \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{-3}\right)}\right) \]
  6. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\left(1 - v \cdot v\right) \cdot \left(0.25 \cdot \sqrt{2 \cdot \left(1 + \left(v \cdot v\right) \cdot -3\right)}\right)} \]
  7. Step-by-step derivation
    1. *-commutativeN/A

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

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

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\color{blue}{\sqrt{2 \cdot \left(1 + \left(v \cdot v\right) \cdot -3\right)}} \cdot \frac{1}{4}\right) \]
    4. distribute-rgt-inN/A

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

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

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

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

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

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

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

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

      \[\leadsto \left(1 - v \cdot v\right) \cdot \left(\sqrt{2 + \left(v \cdot v\right) \cdot \color{blue}{-6}} \cdot 0.25\right) \]
  8. Applied egg-rr100.0%

    \[\leadsto \left(1 - v \cdot v\right) \cdot \color{blue}{\left(\sqrt{2 + \left(v \cdot v\right) \cdot -6} \cdot 0.25\right)} \]
  9. Add Preprocessing

Alternative 2: 99.6% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \sqrt{2} \cdot \left(0.25 + \left(v \cdot v\right) \cdot -0.625\right) \end{array} \]
(FPCore (v) :precision binary64 (* (sqrt 2.0) (+ 0.25 (* (* v v) -0.625))))
double code(double v) {
	return sqrt(2.0) * (0.25 + ((v * v) * -0.625));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt(2.0d0) * (0.25d0 + ((v * v) * (-0.625d0)))
end function
public static double code(double v) {
	return Math.sqrt(2.0) * (0.25 + ((v * v) * -0.625));
}
def code(v):
	return math.sqrt(2.0) * (0.25 + ((v * v) * -0.625))
function code(v)
	return Float64(sqrt(2.0) * Float64(0.25 + Float64(Float64(v * v) * -0.625)))
end
function tmp = code(v)
	tmp = sqrt(2.0) * (0.25 + ((v * v) * -0.625));
end
code[v_] := N[(N[Sqrt[2.0], $MachinePrecision] * N[(0.25 + N[(N[(v * v), $MachinePrecision] * -0.625), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2} \cdot \left(0.25 + \left(v \cdot v\right) \cdot -0.625\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

    \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  4. Step-by-step derivation
    1. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    2. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{{v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    3. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{\left(v \cdot v\right)} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    4. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{\left(v \cdot v\right)} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    5. sub-negN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) + \left(\mathsf{neg}\left(\frac{3}{2}\right)\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    6. metadata-evalN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) + \color{blue}{\frac{-3}{2}}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    7. +-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-3}{2} + {v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    8. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-3}{2} + {v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    9. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{{v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    10. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{\left(v \cdot v\right)} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{\left(v \cdot v\right)} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    12. sub-negN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-27}{16} \cdot {v}^{2} + \left(\mathsf{neg}\left(\frac{9}{8}\right)\right)\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    13. metadata-evalN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-27}{16} \cdot {v}^{2} + \color{blue}{\frac{-9}{8}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    14. +-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-9}{8} + \frac{-27}{16} \cdot {v}^{2}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    15. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-9}{8} + \frac{-27}{16} \cdot {v}^{2}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    16. *-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{{v}^{2} \cdot \frac{-27}{16}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    17. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{{v}^{2} \cdot \frac{-27}{16}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    18. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{\left(v \cdot v\right)} \cdot \frac{-27}{16}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    19. *-lowering-*.f6499.6

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(-1.5 + \left(v \cdot v\right) \cdot \left(-1.125 + \color{blue}{\left(v \cdot v\right)} \cdot -1.6875\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
  5. Simplified99.6%

    \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + \left(v \cdot v\right) \cdot \left(-1.5 + \left(v \cdot v\right) \cdot \left(-1.125 + \left(v \cdot v\right) \cdot -1.6875\right)\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  6. Taylor expanded in v around 0

    \[\leadsto \color{blue}{\frac{-5}{8} \cdot \left({v}^{2} \cdot \sqrt{2}\right) + \frac{1}{4} \cdot \sqrt{2}} \]
  7. Step-by-step derivation
    1. associate-*r*N/A

      \[\leadsto \color{blue}{\left(\frac{-5}{8} \cdot {v}^{2}\right) \cdot \sqrt{2}} + \frac{1}{4} \cdot \sqrt{2} \]
    2. distribute-rgt-outN/A

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\frac{-5}{8} \cdot {v}^{2} + \frac{1}{4}\right)} \]
    3. *-lowering-*.f64N/A

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\frac{-5}{8} \cdot {v}^{2} + \frac{1}{4}\right)} \]
    4. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \color{blue}{\sqrt{2}} \cdot \left(\frac{-5}{8} \cdot {v}^{2} + \frac{1}{4}\right) \]
    5. +-commutativeN/A

      \[\leadsto \sqrt{2} \cdot \color{blue}{\left(\frac{1}{4} + \frac{-5}{8} \cdot {v}^{2}\right)} \]
    6. +-lowering-+.f64N/A

      \[\leadsto \sqrt{2} \cdot \color{blue}{\left(\frac{1}{4} + \frac{-5}{8} \cdot {v}^{2}\right)} \]
    7. *-lowering-*.f64N/A

      \[\leadsto \sqrt{2} \cdot \left(\frac{1}{4} + \color{blue}{\frac{-5}{8} \cdot {v}^{2}}\right) \]
    8. unpow2N/A

      \[\leadsto \sqrt{2} \cdot \left(\frac{1}{4} + \frac{-5}{8} \cdot \color{blue}{\left(v \cdot v\right)}\right) \]
    9. *-lowering-*.f6498.9

      \[\leadsto \sqrt{2} \cdot \left(0.25 + -0.625 \cdot \color{blue}{\left(v \cdot v\right)}\right) \]
  8. Simplified98.9%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(0.25 + -0.625 \cdot \left(v \cdot v\right)\right)} \]
  9. Final simplification98.9%

    \[\leadsto \sqrt{2} \cdot \left(0.25 + \left(v \cdot v\right) \cdot -0.625\right) \]
  10. Add Preprocessing

Alternative 3: 99.0% accurate, 2.1× speedup?

\[\begin{array}{l} \\ {0.015625}^{0.25} \end{array} \]
(FPCore (v) :precision binary64 (pow 0.015625 0.25))
double code(double v) {
	return pow(0.015625, 0.25);
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = 0.015625d0 ** 0.25d0
end function
public static double code(double v) {
	return Math.pow(0.015625, 0.25);
}
def code(v):
	return math.pow(0.015625, 0.25)
function code(v)
	return 0.015625 ^ 0.25
end
function tmp = code(v)
	tmp = 0.015625 ^ 0.25;
end
code[v_] := N[Power[0.015625, 0.25], $MachinePrecision]
\begin{array}{l}

\\
{0.015625}^{0.25}
\end{array}
Derivation
  1. Initial program 100.0%

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

    \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  4. Step-by-step derivation
    1. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    2. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{{v}^{2} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    3. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{\left(v \cdot v\right)} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    4. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \color{blue}{\left(v \cdot v\right)} \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) - \frac{3}{2}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    5. sub-negN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) + \left(\mathsf{neg}\left(\frac{3}{2}\right)\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    6. metadata-evalN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left({v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right) + \color{blue}{\frac{-3}{2}}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    7. +-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-3}{2} + {v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    8. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-3}{2} + {v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)}\right)\right) \cdot \left(1 - v \cdot v\right) \]
    9. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{{v}^{2} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    10. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{\left(v \cdot v\right)} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \color{blue}{\left(v \cdot v\right)} \cdot \left(\frac{-27}{16} \cdot {v}^{2} - \frac{9}{8}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    12. sub-negN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-27}{16} \cdot {v}^{2} + \left(\mathsf{neg}\left(\frac{9}{8}\right)\right)\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    13. metadata-evalN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-27}{16} \cdot {v}^{2} + \color{blue}{\frac{-9}{8}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    14. +-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-9}{8} + \frac{-27}{16} \cdot {v}^{2}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    15. +-lowering-+.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \color{blue}{\left(\frac{-9}{8} + \frac{-27}{16} \cdot {v}^{2}\right)}\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    16. *-commutativeN/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{{v}^{2} \cdot \frac{-27}{16}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    17. *-lowering-*.f64N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{{v}^{2} \cdot \frac{-27}{16}}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    18. unpow2N/A

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \color{blue}{\left(v \cdot v\right)} \cdot \frac{-27}{16}\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
    19. *-lowering-*.f6499.6

      \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \left(1 + \left(v \cdot v\right) \cdot \left(-1.5 + \left(v \cdot v\right) \cdot \left(-1.125 + \color{blue}{\left(v \cdot v\right)} \cdot -1.6875\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right) \]
  5. Simplified99.6%

    \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \color{blue}{\left(1 + \left(v \cdot v\right) \cdot \left(-1.5 + \left(v \cdot v\right) \cdot \left(-1.125 + \left(v \cdot v\right) \cdot -1.6875\right)\right)\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  6. Step-by-step derivation
    1. associate-*l*N/A

      \[\leadsto \color{blue}{\frac{\sqrt{2}}{4} \cdot \left(\left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \left(v \cdot v\right) \cdot \frac{-27}{16}\right)\right)\right) \cdot \left(1 - v \cdot v\right)\right)} \]
    2. clear-numN/A

      \[\leadsto \color{blue}{\frac{1}{\frac{4}{\sqrt{2}}}} \cdot \left(\left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \left(v \cdot v\right) \cdot \frac{-27}{16}\right)\right)\right) \cdot \left(1 - v \cdot v\right)\right) \]
    3. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{1 \cdot \left(\left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \left(v \cdot v\right) \cdot \frac{-27}{16}\right)\right)\right) \cdot \left(1 - v \cdot v\right)\right)}{\frac{4}{\sqrt{2}}}} \]
    4. /-lowering-/.f64N/A

      \[\leadsto \color{blue}{\frac{1 \cdot \left(\left(1 + \left(v \cdot v\right) \cdot \left(\frac{-3}{2} + \left(v \cdot v\right) \cdot \left(\frac{-9}{8} + \left(v \cdot v\right) \cdot \frac{-27}{16}\right)\right)\right) \cdot \left(1 - v \cdot v\right)\right)}{\frac{4}{\sqrt{2}}}} \]
  7. Applied egg-rr98.1%

    \[\leadsto \color{blue}{\frac{1 \cdot \left(\left(1 + v \cdot \left(v \cdot \left(-1.5 + v \cdot \left(v \cdot \left(-1.125 + \left(v \cdot v\right) \cdot -1.6875\right)\right)\right)\right)\right) \cdot \left(1 - v \cdot v\right)\right)}{{4}^{0.75}}} \]
  8. Taylor expanded in v around 0

    \[\leadsto \color{blue}{{\frac{1}{64}}^{\frac{1}{4}}} \]
  9. Step-by-step derivation
    1. pow-lowering-pow.f6498.4

      \[\leadsto \color{blue}{{0.015625}^{0.25}} \]
  10. Simplified98.4%

    \[\leadsto \color{blue}{{0.015625}^{0.25}} \]
  11. Add Preprocessing

Reproduce

?
herbie shell --seed 2024191 
(FPCore (v)
  :name "Falkner and Boettcher, Appendix B, 2"
  :precision binary64
  (* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))