Falkner and Boettcher, Appendix B, 2

Percentage Accurate: 100.0% → 100.0%
Time: 8.5s
Alternatives: 4
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 4 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?

\[\begin{array}{l} \\ \left(0.25 + \frac{v \cdot v}{-4}\right) \cdot \sqrt{\left(v \cdot v\right) \cdot -6 + 2} \end{array} \]
(FPCore (v)
 :precision binary64
 (* (+ 0.25 (/ (* v v) -4.0)) (sqrt (+ (* (* v v) -6.0) 2.0))))
double code(double v) {
	return (0.25 + ((v * v) / -4.0)) * sqrt((((v * v) * -6.0) + 2.0));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = (0.25d0 + ((v * v) / (-4.0d0))) * sqrt((((v * v) * (-6.0d0)) + 2.0d0))
end function
public static double code(double v) {
	return (0.25 + ((v * v) / -4.0)) * Math.sqrt((((v * v) * -6.0) + 2.0));
}
def code(v):
	return (0.25 + ((v * v) / -4.0)) * math.sqrt((((v * v) * -6.0) + 2.0))
function code(v)
	return Float64(Float64(0.25 + Float64(Float64(v * v) / -4.0)) * sqrt(Float64(Float64(Float64(v * v) * -6.0) + 2.0)))
end
function tmp = code(v)
	tmp = (0.25 + ((v * v) / -4.0)) * sqrt((((v * v) * -6.0) + 2.0));
end
code[v_] := N[(N[(0.25 + N[(N[(v * v), $MachinePrecision] / -4.0), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(N[(N[(v * v), $MachinePrecision] * -6.0), $MachinePrecision] + 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(0.25 + \frac{v \cdot v}{-4}\right) \cdot \sqrt{\left(v \cdot v\right) \cdot -6 + 2}
\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. Step-by-step derivation
    1. associate-*l/N/A

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

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\sqrt{2}\right), \color{blue}{\left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4} \cdot \left(1 - v \cdot v\right)\right)}\right) \]
    5. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\color{blue}{\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4}} \cdot \left(1 - v \cdot v\right)\right)\right) \]
    6. associate-*l/N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}{\color{blue}{4}}\right)\right) \]
    7. associate-/l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \color{blue}{\frac{1 - v \cdot v}{4}}\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right), \color{blue}{\left(\frac{1 - v \cdot v}{4}\right)}\right)\right) \]
    9. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 - 3 \cdot \left(v \cdot v\right)\right)\right), \left(\frac{\color{blue}{1 - v \cdot v}}{4}\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    11. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(\left(v \cdot v\right) \cdot 3\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    13. distribute-rgt-neg-inN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(v \cdot v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    17. div-subN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1}{4} - \color{blue}{\frac{v \cdot v}{4}}\right)\right)\right) \]
    18. --lowering--.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \mathsf{\_.f64}\left(\left(\frac{1}{4}\right), \color{blue}{\left(\frac{v \cdot v}{4}\right)}\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\sqrt{1 + \left(v \cdot v\right) \cdot -3} \cdot \left(0.25 - v \cdot \frac{v}{4}\right)\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. pow1/2N/A

      \[\leadsto \mathsf{*.f64}\left(\left({2}^{\frac{1}{2}}\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right)}, \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
    2. sqr-powN/A

      \[\leadsto \mathsf{*.f64}\left(\left({2}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {2}^{\left(\frac{\frac{1}{2}}{2}\right)}\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right)}, \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
    3. pow2N/A

      \[\leadsto \mathsf{*.f64}\left(\left({\left({2}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)}^{2}\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right)}, \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
    4. pow-lowering-pow.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{pow.f64}\left(\left({2}^{\left(\frac{\frac{1}{2}}{2}\right)}\right), 2\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right)}, \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
    5. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{pow.f64}\left(\left({2}^{\frac{1}{4}}\right), 2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \color{blue}{\mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)}\right)\right), \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
    6. pow-lowering-pow.f6498.5%

      \[\leadsto \mathsf{*.f64}\left(\mathsf{pow.f64}\left(\mathsf{pow.f64}\left(2, \frac{1}{4}\right), 2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\color{blue}{\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)}\right), \mathsf{\_.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{/.f64}\left(v, 4\right)\right)\right)\right)\right) \]
  6. Applied egg-rr98.5%

    \[\leadsto \color{blue}{{\left({2}^{0.25}\right)}^{2}} \cdot \left(\sqrt{1 + \left(v \cdot v\right) \cdot -3} \cdot \left(0.25 - v \cdot \frac{v}{4}\right)\right) \]
  7. Step-by-step derivation
    1. pow-powN/A

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

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

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

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\frac{1}{4} - v \cdot \frac{v}{4}\right), \color{blue}{\left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)}\right) \]
    7. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\left(\frac{1}{4} + \left(\mathsf{neg}\left(v \cdot \frac{v}{4}\right)\right)\right), \left(\color{blue}{\sqrt{2}} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    8. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \left(\mathsf{neg}\left(v \cdot \frac{v}{4}\right)\right)\right), \left(\color{blue}{\sqrt{2}} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    9. associate-*r/N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \left(\mathsf{neg}\left(\frac{v \cdot v}{4}\right)\right)\right), \left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    10. distribute-neg-frac2N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \left(\frac{v \cdot v}{\mathsf{neg}\left(4\right)}\right)\right), \left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    11. /-lowering-/.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\left(v \cdot v\right), \left(\mathsf{neg}\left(4\right)\right)\right)\right), \left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    12. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(\mathsf{neg}\left(4\right)\right)\right)\right), \left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    13. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \left(\sqrt{2} \cdot \sqrt{1 + \left(v \cdot v\right) \cdot -3}\right)\right) \]
    14. sqrt-unprodN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \left(\sqrt{2 \cdot \left(1 + \left(v \cdot v\right) \cdot -3\right)}\right)\right) \]
    15. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\left(2 \cdot \left(1 + \left(v \cdot v\right) \cdot -3\right)\right)\right)\right) \]
    16. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{*.f64}\left(2, \left(1 + \left(v \cdot v\right) \cdot -3\right)\right)\right)\right) \]
    17. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{*.f64}\left(2, \mathsf{+.f64}\left(1, \left(\left(v \cdot v\right) \cdot -3\right)\right)\right)\right)\right) \]
    18. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{*.f64}\left(2, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(v \cdot v\right), -3\right)\right)\right)\right)\right) \]
    19. *-lowering-*.f64100.0%

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{*.f64}\left(2, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right)\right)\right) \]
  8. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\left(0.25 + \frac{v \cdot v}{-4}\right) \cdot \sqrt{2 \cdot \left(1 + \left(v \cdot v\right) \cdot -3\right)}} \]
  9. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\left(2 \cdot \left(\left(v \cdot v\right) \cdot -3 + 1\right)\right)\right)\right) \]
    2. distribute-rgt-inN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\left(\left(\left(v \cdot v\right) \cdot -3\right) \cdot 2 + 1 \cdot 2\right)\right)\right) \]
    3. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\left(\left(\left(v \cdot v\right) \cdot -3\right) \cdot 2 + 2\right)\right)\right) \]
    4. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\left(\left(\left(v \cdot v\right) \cdot -3\right) \cdot 2\right), 2\right)\right)\right) \]
    5. associate-*l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\left(\left(v \cdot v\right) \cdot \left(-3 \cdot 2\right)\right), 2\right)\right)\right) \]
    6. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\left(\left(v \cdot v\right) \cdot -6\right), 2\right)\right)\right) \]
    7. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\left(\left(v \cdot v\right) \cdot \left(2 \cdot -3\right)\right), 2\right)\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\mathsf{*.f64}\left(\left(v \cdot v\right), \left(2 \cdot -3\right)\right), 2\right)\right)\right) \]
    9. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(2 \cdot -3\right)\right), 2\right)\right)\right) \]
    10. metadata-eval100.0%

      \[\leadsto \mathsf{*.f64}\left(\mathsf{+.f64}\left(\frac{1}{4}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(v, v\right), -4\right)\right), \mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -6\right), 2\right)\right)\right) \]
  10. Applied egg-rr100.0%

    \[\leadsto \left(0.25 + \frac{v \cdot v}{-4}\right) \cdot \sqrt{\color{blue}{\left(v \cdot v\right) \cdot -6 + 2}} \]
  11. Add Preprocessing

Alternative 2: 99.7% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \sqrt{2} \cdot \left(0.25 + v \cdot \left(v \cdot \left(-0.625 + \left(v \cdot v\right) \cdot 0.09375\right)\right)\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (* (sqrt 2.0) (+ 0.25 (* v (* v (+ -0.625 (* (* v v) 0.09375)))))))
double code(double v) {
	return sqrt(2.0) * (0.25 + (v * (v * (-0.625 + ((v * v) * 0.09375)))));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt(2.0d0) * (0.25d0 + (v * (v * ((-0.625d0) + ((v * v) * 0.09375d0)))))
end function
public static double code(double v) {
	return Math.sqrt(2.0) * (0.25 + (v * (v * (-0.625 + ((v * v) * 0.09375)))));
}
def code(v):
	return math.sqrt(2.0) * (0.25 + (v * (v * (-0.625 + ((v * v) * 0.09375)))))
function code(v)
	return Float64(sqrt(2.0) * Float64(0.25 + Float64(v * Float64(v * Float64(-0.625 + Float64(Float64(v * v) * 0.09375))))))
end
function tmp = code(v)
	tmp = sqrt(2.0) * (0.25 + (v * (v * (-0.625 + ((v * v) * 0.09375)))));
end
code[v_] := N[(N[Sqrt[2.0], $MachinePrecision] * N[(0.25 + N[(v * N[(v * N[(-0.625 + N[(N[(v * v), $MachinePrecision] * 0.09375), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2} \cdot \left(0.25 + v \cdot \left(v \cdot \left(-0.625 + \left(v \cdot v\right) \cdot 0.09375\right)\right)\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. Step-by-step derivation
    1. associate-*l/N/A

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

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\sqrt{2}\right), \color{blue}{\left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4} \cdot \left(1 - v \cdot v\right)\right)}\right) \]
    5. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\color{blue}{\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4}} \cdot \left(1 - v \cdot v\right)\right)\right) \]
    6. associate-*l/N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}{\color{blue}{4}}\right)\right) \]
    7. associate-/l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \color{blue}{\frac{1 - v \cdot v}{4}}\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right), \color{blue}{\left(\frac{1 - v \cdot v}{4}\right)}\right)\right) \]
    9. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 - 3 \cdot \left(v \cdot v\right)\right)\right), \left(\frac{\color{blue}{1 - v \cdot v}}{4}\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    11. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(\left(v \cdot v\right) \cdot 3\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    13. distribute-rgt-neg-inN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(v \cdot v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    17. div-subN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1}{4} - \color{blue}{\frac{v \cdot v}{4}}\right)\right)\right) \]
    18. --lowering--.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \mathsf{\_.f64}\left(\left(\frac{1}{4}\right), \color{blue}{\left(\frac{v \cdot v}{4}\right)}\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\sqrt{1 + \left(v \cdot v\right) \cdot -3} \cdot \left(0.25 - v \cdot \frac{v}{4}\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0

    \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \color{blue}{\left(\frac{1}{4} + {v}^{2} \cdot \left(\frac{3}{32} \cdot {v}^{2} - \frac{5}{8}\right)\right)}\right) \]
  6. Step-by-step derivation
    1. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \color{blue}{\left({v}^{2} \cdot \left(\frac{3}{32} \cdot {v}^{2} - \frac{5}{8}\right)\right)}\right)\right) \]
    2. unpow2N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \left(\left(v \cdot v\right) \cdot \left(\color{blue}{\frac{3}{32} \cdot {v}^{2}} - \frac{5}{8}\right)\right)\right)\right) \]
    3. associate-*l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \left(v \cdot \color{blue}{\left(v \cdot \left(\frac{3}{32} \cdot {v}^{2} - \frac{5}{8}\right)\right)}\right)\right)\right) \]
    4. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \color{blue}{\left(v \cdot \left(\frac{3}{32} \cdot {v}^{2} - \frac{5}{8}\right)\right)}\right)\right)\right) \]
    5. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \color{blue}{\left(\frac{3}{32} \cdot {v}^{2} - \frac{5}{8}\right)}\right)\right)\right)\right) \]
    6. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \left(\frac{3}{32} \cdot {v}^{2} + \color{blue}{\left(\mathsf{neg}\left(\frac{5}{8}\right)\right)}\right)\right)\right)\right)\right) \]
    7. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \left(\frac{3}{32} \cdot {v}^{2} + \frac{-5}{8}\right)\right)\right)\right)\right) \]
    8. +-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \left(\frac{-5}{8} + \color{blue}{\frac{3}{32} \cdot {v}^{2}}\right)\right)\right)\right)\right) \]
    9. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \mathsf{+.f64}\left(\frac{-5}{8}, \color{blue}{\left(\frac{3}{32} \cdot {v}^{2}\right)}\right)\right)\right)\right)\right) \]
    10. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \mathsf{+.f64}\left(\frac{-5}{8}, \left({v}^{2} \cdot \color{blue}{\frac{3}{32}}\right)\right)\right)\right)\right)\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \mathsf{+.f64}\left(\frac{-5}{8}, \mathsf{*.f64}\left(\left({v}^{2}\right), \color{blue}{\frac{3}{32}}\right)\right)\right)\right)\right)\right) \]
    12. unpow2N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \mathsf{+.f64}\left(\frac{-5}{8}, \mathsf{*.f64}\left(\left(v \cdot v\right), \frac{3}{32}\right)\right)\right)\right)\right)\right) \]
    13. *-lowering-*.f6499.3%

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(v, \mathsf{*.f64}\left(v, \mathsf{+.f64}\left(\frac{-5}{8}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \frac{3}{32}\right)\right)\right)\right)\right)\right) \]
  7. Simplified99.3%

    \[\leadsto \sqrt{2} \cdot \color{blue}{\left(0.25 + v \cdot \left(v \cdot \left(-0.625 + \left(v \cdot v\right) \cdot 0.09375\right)\right)\right)} \]
  8. Add Preprocessing

Alternative 3: 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. Step-by-step derivation
    1. associate-*l/N/A

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

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\sqrt{2}\right), \color{blue}{\left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4} \cdot \left(1 - v \cdot v\right)\right)}\right) \]
    5. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\color{blue}{\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4}} \cdot \left(1 - v \cdot v\right)\right)\right) \]
    6. associate-*l/N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}{\color{blue}{4}}\right)\right) \]
    7. associate-/l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \color{blue}{\frac{1 - v \cdot v}{4}}\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right), \color{blue}{\left(\frac{1 - v \cdot v}{4}\right)}\right)\right) \]
    9. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 - 3 \cdot \left(v \cdot v\right)\right)\right), \left(\frac{\color{blue}{1 - v \cdot v}}{4}\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    11. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(\left(v \cdot v\right) \cdot 3\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    13. distribute-rgt-neg-inN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(v \cdot v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    17. div-subN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1}{4} - \color{blue}{\frac{v \cdot v}{4}}\right)\right)\right) \]
    18. --lowering--.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \mathsf{\_.f64}\left(\left(\frac{1}{4}\right), \color{blue}{\left(\frac{v \cdot v}{4}\right)}\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\sqrt{1 + \left(v \cdot v\right) \cdot -3} \cdot \left(0.25 - v \cdot \frac{v}{4}\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0

    \[\leadsto \color{blue}{\frac{1}{4} \cdot \sqrt{2} + {v}^{2} \cdot \left(\frac{-3}{8} \cdot \sqrt{2} + \frac{-1}{4} \cdot \sqrt{2}\right)} \]
  6. Step-by-step derivation
    1. *-commutativeN/A

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

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

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

      \[\leadsto \sqrt{2} \cdot \frac{1}{4} + \left(\sqrt{2} \cdot \frac{-5}{8}\right) \cdot {v}^{2} \]
    5. associate-*l*N/A

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\sqrt{2}\right), \color{blue}{\left(\frac{1}{4} + \frac{-5}{8} \cdot {v}^{2}\right)}\right) \]
    8. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\color{blue}{\frac{1}{4}} + \frac{-5}{8} \cdot {v}^{2}\right)\right) \]
    9. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \color{blue}{\left(\frac{-5}{8} \cdot {v}^{2}\right)}\right)\right) \]
    10. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \left({v}^{2} \cdot \color{blue}{\frac{-5}{8}}\right)\right)\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(\left({v}^{2}\right), \color{blue}{\frac{-5}{8}}\right)\right)\right) \]
    12. unpow2N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(\left(v \cdot v\right), \frac{-5}{8}\right)\right)\right) \]
    13. *-lowering-*.f6498.8%

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{+.f64}\left(\frac{1}{4}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \frac{-5}{8}\right)\right)\right) \]
  7. Simplified98.8%

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

Alternative 4: 99.0% accurate, 2.1× speedup?

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

\\
0.25 \cdot \sqrt{2}
\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. Step-by-step derivation
    1. associate-*l/N/A

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

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

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

      \[\leadsto \mathsf{*.f64}\left(\left(\sqrt{2}\right), \color{blue}{\left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4} \cdot \left(1 - v \cdot v\right)\right)}\right) \]
    5. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\color{blue}{\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}{4}} \cdot \left(1 - v \cdot v\right)\right)\right) \]
    6. associate-*l/N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\frac{\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)}{\color{blue}{4}}\right)\right) \]
    7. associate-/l*N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \color{blue}{\frac{1 - v \cdot v}{4}}\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right), \color{blue}{\left(\frac{1 - v \cdot v}{4}\right)}\right)\right) \]
    9. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 - 3 \cdot \left(v \cdot v\right)\right)\right), \left(\frac{\color{blue}{1 - v \cdot v}}{4}\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\left(1 + \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    11. +-lowering-+.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(3 \cdot \left(v \cdot v\right)\right)\right)\right)\right), \left(\frac{\color{blue}{1} - v \cdot v}{4}\right)\right)\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\mathsf{neg}\left(\left(v \cdot v\right) \cdot 3\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    13. distribute-rgt-neg-inN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \left(\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(v \cdot v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), \left(\mathsf{neg}\left(3\right)\right)\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1 - v \cdot v}{4}\right)\right)\right) \]
    17. div-subN/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \left(\frac{1}{4} - \color{blue}{\frac{v \cdot v}{4}}\right)\right)\right) \]
    18. --lowering--.f64N/A

      \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(\mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(v, v\right), -3\right)\right)\right), \mathsf{\_.f64}\left(\left(\frac{1}{4}\right), \color{blue}{\left(\frac{v \cdot v}{4}\right)}\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(\sqrt{1 + \left(v \cdot v\right) \cdot -3} \cdot \left(0.25 - v \cdot \frac{v}{4}\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0

    \[\leadsto \mathsf{*.f64}\left(\mathsf{sqrt.f64}\left(2\right), \color{blue}{\frac{1}{4}}\right) \]
  6. Step-by-step derivation
    1. Simplified97.7%

      \[\leadsto \sqrt{2} \cdot \color{blue}{0.25} \]
    2. Final simplification97.7%

      \[\leadsto 0.25 \cdot \sqrt{2} \]
    3. Add Preprocessing

    Reproduce

    ?
    herbie shell --seed 2024155 
    (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))))