Falkner and Boettcher, Appendix B, 2

Percentage Accurate: 100.0% → 100.0%
Time: 7.6s
Alternatives: 6
Speedup: 1.0×

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 6 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 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, 1.0× speedup?

\[\begin{array}{l} \\ \left(\sqrt{0.125} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (* (* (sqrt 0.125) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))
double code(double v) {
	return (sqrt(0.125) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = (sqrt(0.125d0) * sqrt((1.0d0 - (3.0d0 * (v * v))))) * (1.0d0 - (v * v))
end function
public static double code(double v) {
	return (Math.sqrt(0.125) * Math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
def code(v):
	return (math.sqrt(0.125) * math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v))
function code(v)
	return Float64(Float64(sqrt(0.125) * sqrt(Float64(1.0 - Float64(3.0 * Float64(v * v))))) * Float64(1.0 - Float64(v * v)))
end
function tmp = code(v)
	tmp = (sqrt(0.125) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
end
code[v_] := N[(N[(N[Sqrt[0.125], $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(\sqrt{0.125} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\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. *-un-lft-identity100.0%

      \[\leadsto \left(\color{blue}{\left(1 \cdot \frac{\sqrt{2}}{4}\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    2. *-commutative100.0%

      \[\leadsto \left(\color{blue}{\left(\frac{\sqrt{2}}{4} \cdot 1\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    3. add-sqr-sqrt98.5%

      \[\leadsto \left(\left(\color{blue}{\left(\sqrt{\frac{\sqrt{2}}{4}} \cdot \sqrt{\frac{\sqrt{2}}{4}}\right)} \cdot 1\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    4. sqrt-unprod100.0%

      \[\leadsto \left(\left(\color{blue}{\sqrt{\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}}} \cdot 1\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    5. frac-times100.0%

      \[\leadsto \left(\left(\sqrt{\color{blue}{\frac{\sqrt{2} \cdot \sqrt{2}}{4 \cdot 4}}} \cdot 1\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    6. rem-square-sqrt100.0%

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

      \[\leadsto \left(\left(\sqrt{\frac{2}{\color{blue}{16}}} \cdot 1\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
    8. metadata-eval100.0%

      \[\leadsto \left(\left(\sqrt{\color{blue}{0.125}} \cdot 1\right) \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \left(\color{blue}{\left(\sqrt{0.125} \cdot 1\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  5. Step-by-step derivation
    1. *-rgt-identity100.0%

      \[\leadsto \left(\color{blue}{\sqrt{0.125}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  6. Simplified100.0%

    \[\leadsto \left(\color{blue}{\sqrt{0.125}} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  7. Add Preprocessing

Alternative 2: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(1 - v \cdot v\right) \cdot \sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot -3\right)} \end{array} \]
(FPCore (v)
 :precision binary64
 (* (- 1.0 (* v v)) (sqrt (* 0.125 (+ 1.0 (* (pow v 2.0) -3.0))))))
double code(double v) {
	return (1.0 - (v * v)) * sqrt((0.125 * (1.0 + (pow(v, 2.0) * -3.0))));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = (1.0d0 - (v * v)) * sqrt((0.125d0 * (1.0d0 + ((v ** 2.0d0) * (-3.0d0)))))
end function
public static double code(double v) {
	return (1.0 - (v * v)) * Math.sqrt((0.125 * (1.0 + (Math.pow(v, 2.0) * -3.0))));
}
def code(v):
	return (1.0 - (v * v)) * math.sqrt((0.125 * (1.0 + (math.pow(v, 2.0) * -3.0))))
function code(v)
	return Float64(Float64(1.0 - Float64(v * v)) * sqrt(Float64(0.125 * Float64(1.0 + Float64((v ^ 2.0) * -3.0)))))
end
function tmp = code(v)
	tmp = (1.0 - (v * v)) * sqrt((0.125 * (1.0 + ((v ^ 2.0) * -3.0))));
end
code[v_] := N[(N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(0.125 * N[(1.0 + N[(N[Power[v, 2.0], $MachinePrecision] * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(1 - v \cdot v\right) \cdot \sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot -3\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. add-sqr-sqrt98.5%

      \[\leadsto \color{blue}{\left(\sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}} \cdot \sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}}\right)} \cdot \left(1 - v \cdot v\right) \]
    2. sqrt-unprod100.0%

      \[\leadsto \color{blue}{\sqrt{\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)}} \cdot \left(1 - v \cdot v\right) \]
    3. *-commutative100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)} \cdot \left(1 - v \cdot v\right) \]
    4. *-commutative100.0%

      \[\leadsto \sqrt{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right) \cdot \color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    5. swap-sqr100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    6. add-sqr-sqrt99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    7. sub-neg99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 + \left(-3 \cdot \left(v \cdot v\right)\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    8. +-commutative99.9%

      \[\leadsto \sqrt{\color{blue}{\left(\left(-3 \cdot \left(v \cdot v\right)\right) + 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    9. *-commutative99.9%

      \[\leadsto \sqrt{\left(\left(-\color{blue}{\left(v \cdot v\right) \cdot 3}\right) + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    10. distribute-rgt-neg-in99.9%

      \[\leadsto \sqrt{\left(\color{blue}{\left(v \cdot v\right) \cdot \left(-3\right)} + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    11. fma-define99.9%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, -3, 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    12. pow299.9%

      \[\leadsto \sqrt{\mathsf{fma}\left(\color{blue}{{v}^{2}}, -3, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    13. metadata-eval99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, \color{blue}{-3}, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    14. frac-times99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \color{blue}{\frac{\sqrt{2} \cdot \sqrt{2}}{4 \cdot 4}}} \cdot \left(1 - v \cdot v\right) \]
    15. rem-square-sqrt100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{\color{blue}{2}}{4 \cdot 4}} \cdot \left(1 - v \cdot v\right) \]
    16. metadata-eval100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{2}{\color{blue}{16}}} \cdot \left(1 - v \cdot v\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot 0.125}} \cdot \left(1 - v \cdot v\right) \]
  5. Step-by-step derivation
    1. fma-undefine100.0%

      \[\leadsto \sqrt{\color{blue}{\left({v}^{2} \cdot -3 + 1\right)} \cdot 0.125} \cdot \left(1 - v \cdot v\right) \]
  6. Applied egg-rr100.0%

    \[\leadsto \sqrt{\color{blue}{\left({v}^{2} \cdot -3 + 1\right)} \cdot 0.125} \cdot \left(1 - v \cdot v\right) \]
  7. Final simplification100.0%

    \[\leadsto \left(1 - v \cdot v\right) \cdot \sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot -3\right)} \]
  8. Add Preprocessing

Alternative 3: 99.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{0.125} + \left(v \cdot v\right) \cdot \left(-0.625 \cdot \sqrt{2}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (+ (sqrt 0.125) (* (* v v) (* -0.625 (sqrt 2.0)))))
double code(double v) {
	return sqrt(0.125) + ((v * v) * (-0.625 * sqrt(2.0)));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt(0.125d0) + ((v * v) * ((-0.625d0) * sqrt(2.0d0)))
end function
public static double code(double v) {
	return Math.sqrt(0.125) + ((v * v) * (-0.625 * Math.sqrt(2.0)));
}
def code(v):
	return math.sqrt(0.125) + ((v * v) * (-0.625 * math.sqrt(2.0)))
function code(v)
	return Float64(sqrt(0.125) + Float64(Float64(v * v) * Float64(-0.625 * sqrt(2.0))))
end
function tmp = code(v)
	tmp = sqrt(0.125) + ((v * v) * (-0.625 * sqrt(2.0)));
end
code[v_] := N[(N[Sqrt[0.125], $MachinePrecision] + N[(N[(v * v), $MachinePrecision] * N[(-0.625 * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.125} + \left(v \cdot v\right) \cdot \left(-0.625 \cdot \sqrt{2}\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 99.6%

    \[\leadsto \color{blue}{0.25 \cdot \sqrt{2} + 0.25 \cdot \left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + -1 \cdot \sqrt{2}\right)\right)} \]
  4. Step-by-step derivation
    1. distribute-lft-out99.6%

      \[\leadsto \color{blue}{0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + -1 \cdot \sqrt{2}\right)\right)} \]
    2. neg-mul-199.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + \color{blue}{\left(-\sqrt{2}\right)}\right)\right) \]
    3. distribute-lft-in99.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + \color{blue}{\left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)}\right) \]
    4. associate-+r+99.6%

      \[\leadsto 0.25 \cdot \color{blue}{\left(\left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right)\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)} \]
    5. *-commutative99.6%

      \[\leadsto 0.25 \cdot \left(\left(\sqrt{2} + \color{blue}{\left(-1.5 \cdot \sqrt{2}\right) \cdot {v}^{2}}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right) \]
    6. *-commutative99.6%

      \[\leadsto 0.25 \cdot \left(\left(\sqrt{2} + \color{blue}{{v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right)}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right) \]
    7. associate-+r+99.6%

      \[\leadsto 0.25 \cdot \color{blue}{\left(\sqrt{2} + \left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)\right)} \]
    8. distribute-lft-in99.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + \color{blue}{{v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + \left(-\sqrt{2}\right)\right)}\right) \]
  5. Simplified99.6%

    \[\leadsto \color{blue}{0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(\sqrt{2} \cdot -2.5\right)\right)} \]
  6. Taylor expanded in v around 0 99.6%

    \[\leadsto \color{blue}{-0.625 \cdot \left({v}^{2} \cdot \sqrt{2}\right) + 0.25 \cdot \sqrt{2}} \]
  7. Step-by-step derivation
    1. associate-*r*99.6%

      \[\leadsto \color{blue}{\left(-0.625 \cdot {v}^{2}\right) \cdot \sqrt{2}} + 0.25 \cdot \sqrt{2} \]
    2. distribute-rgt-out99.6%

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left(-0.625 \cdot {v}^{2} + 0.25\right)} \]
    3. +-commutative99.6%

      \[\leadsto \sqrt{2} \cdot \color{blue}{\left(0.25 + -0.625 \cdot {v}^{2}\right)} \]
    4. *-commutative99.6%

      \[\leadsto \sqrt{2} \cdot \left(0.25 + \color{blue}{{v}^{2} \cdot -0.625}\right) \]
  8. Simplified99.6%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(0.25 + {v}^{2} \cdot -0.625\right)} \]
  9. Step-by-step derivation
    1. +-commutative99.6%

      \[\leadsto \sqrt{2} \cdot \color{blue}{\left({v}^{2} \cdot -0.625 + 0.25\right)} \]
    2. distribute-lft-in99.6%

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left({v}^{2} \cdot -0.625\right) + \sqrt{2} \cdot 0.25} \]
    3. *-commutative99.6%

      \[\leadsto \color{blue}{\left({v}^{2} \cdot -0.625\right) \cdot \sqrt{2}} + \sqrt{2} \cdot 0.25 \]
    4. associate-*l*99.6%

      \[\leadsto \color{blue}{{v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right)} + \sqrt{2} \cdot 0.25 \]
    5. add-sqr-sqrt98.1%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \color{blue}{\sqrt{\sqrt{2} \cdot 0.25} \cdot \sqrt{\sqrt{2} \cdot 0.25}} \]
    6. sqrt-unprod99.6%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \color{blue}{\sqrt{\left(\sqrt{2} \cdot 0.25\right) \cdot \left(\sqrt{2} \cdot 0.25\right)}} \]
    7. swap-sqr99.6%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{\color{blue}{\left(\sqrt{2} \cdot \sqrt{2}\right) \cdot \left(0.25 \cdot 0.25\right)}} \]
    8. rem-square-sqrt99.6%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{\color{blue}{2} \cdot \left(0.25 \cdot 0.25\right)} \]
    9. metadata-eval99.6%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{2 \cdot \color{blue}{0.0625}} \]
    10. metadata-eval99.6%

      \[\leadsto {v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{\color{blue}{0.125}} \]
  10. Applied egg-rr99.6%

    \[\leadsto \color{blue}{{v}^{2} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{0.125}} \]
  11. Step-by-step derivation
    1. unpow299.6%

      \[\leadsto \color{blue}{\left(v \cdot v\right)} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{0.125} \]
  12. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\left(v \cdot v\right)} \cdot \left(-0.625 \cdot \sqrt{2}\right) + \sqrt{0.125} \]
  13. Final simplification99.6%

    \[\leadsto \sqrt{0.125} + \left(v \cdot v\right) \cdot \left(-0.625 \cdot \sqrt{2}\right) \]
  14. Add Preprocessing

Alternative 4: 99.6% accurate, 1.0× speedup?

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

\\
\sqrt{2} \cdot \left(0.25 + {v}^{2} \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 99.6%

    \[\leadsto \color{blue}{0.25 \cdot \sqrt{2} + 0.25 \cdot \left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + -1 \cdot \sqrt{2}\right)\right)} \]
  4. Step-by-step derivation
    1. distribute-lft-out99.6%

      \[\leadsto \color{blue}{0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + -1 \cdot \sqrt{2}\right)\right)} \]
    2. neg-mul-199.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + \color{blue}{\left(-\sqrt{2}\right)}\right)\right) \]
    3. distribute-lft-in99.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + \color{blue}{\left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)}\right) \]
    4. associate-+r+99.6%

      \[\leadsto 0.25 \cdot \color{blue}{\left(\left(\sqrt{2} + {v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right)\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)} \]
    5. *-commutative99.6%

      \[\leadsto 0.25 \cdot \left(\left(\sqrt{2} + \color{blue}{\left(-1.5 \cdot \sqrt{2}\right) \cdot {v}^{2}}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right) \]
    6. *-commutative99.6%

      \[\leadsto 0.25 \cdot \left(\left(\sqrt{2} + \color{blue}{{v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right)}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right) \]
    7. associate-+r+99.6%

      \[\leadsto 0.25 \cdot \color{blue}{\left(\sqrt{2} + \left({v}^{2} \cdot \left(-1.5 \cdot \sqrt{2}\right) + {v}^{2} \cdot \left(-\sqrt{2}\right)\right)\right)} \]
    8. distribute-lft-in99.6%

      \[\leadsto 0.25 \cdot \left(\sqrt{2} + \color{blue}{{v}^{2} \cdot \left(-1.5 \cdot \sqrt{2} + \left(-\sqrt{2}\right)\right)}\right) \]
  5. Simplified99.6%

    \[\leadsto \color{blue}{0.25 \cdot \left(\sqrt{2} + {v}^{2} \cdot \left(\sqrt{2} \cdot -2.5\right)\right)} \]
  6. Taylor expanded in v around 0 99.6%

    \[\leadsto \color{blue}{-0.625 \cdot \left({v}^{2} \cdot \sqrt{2}\right) + 0.25 \cdot \sqrt{2}} \]
  7. Step-by-step derivation
    1. associate-*r*99.6%

      \[\leadsto \color{blue}{\left(-0.625 \cdot {v}^{2}\right) \cdot \sqrt{2}} + 0.25 \cdot \sqrt{2} \]
    2. distribute-rgt-out99.6%

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left(-0.625 \cdot {v}^{2} + 0.25\right)} \]
    3. +-commutative99.6%

      \[\leadsto \sqrt{2} \cdot \color{blue}{\left(0.25 + -0.625 \cdot {v}^{2}\right)} \]
    4. *-commutative99.6%

      \[\leadsto \sqrt{2} \cdot \left(0.25 + \color{blue}{{v}^{2} \cdot -0.625}\right) \]
  8. Simplified99.6%

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

Alternative 5: 99.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \sqrt{0.125} \cdot \left(1 - v \cdot v\right) \end{array} \]
(FPCore (v) :precision binary64 (* (sqrt 0.125) (- 1.0 (* v v))))
double code(double v) {
	return sqrt(0.125) * (1.0 - (v * v));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt(0.125d0) * (1.0d0 - (v * v))
end function
public static double code(double v) {
	return Math.sqrt(0.125) * (1.0 - (v * v));
}
def code(v):
	return math.sqrt(0.125) * (1.0 - (v * v))
function code(v)
	return Float64(sqrt(0.125) * Float64(1.0 - Float64(v * v)))
end
function tmp = code(v)
	tmp = sqrt(0.125) * (1.0 - (v * v));
end
code[v_] := N[(N[Sqrt[0.125], $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.125} \cdot \left(1 - v \cdot v\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. add-sqr-sqrt98.5%

      \[\leadsto \color{blue}{\left(\sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}} \cdot \sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}}\right)} \cdot \left(1 - v \cdot v\right) \]
    2. sqrt-unprod100.0%

      \[\leadsto \color{blue}{\sqrt{\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)}} \cdot \left(1 - v \cdot v\right) \]
    3. *-commutative100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)} \cdot \left(1 - v \cdot v\right) \]
    4. *-commutative100.0%

      \[\leadsto \sqrt{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right) \cdot \color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    5. swap-sqr100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    6. add-sqr-sqrt99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    7. sub-neg99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 + \left(-3 \cdot \left(v \cdot v\right)\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    8. +-commutative99.9%

      \[\leadsto \sqrt{\color{blue}{\left(\left(-3 \cdot \left(v \cdot v\right)\right) + 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    9. *-commutative99.9%

      \[\leadsto \sqrt{\left(\left(-\color{blue}{\left(v \cdot v\right) \cdot 3}\right) + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    10. distribute-rgt-neg-in99.9%

      \[\leadsto \sqrt{\left(\color{blue}{\left(v \cdot v\right) \cdot \left(-3\right)} + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    11. fma-define99.9%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, -3, 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    12. pow299.9%

      \[\leadsto \sqrt{\mathsf{fma}\left(\color{blue}{{v}^{2}}, -3, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    13. metadata-eval99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, \color{blue}{-3}, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    14. frac-times99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \color{blue}{\frac{\sqrt{2} \cdot \sqrt{2}}{4 \cdot 4}}} \cdot \left(1 - v \cdot v\right) \]
    15. rem-square-sqrt100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{\color{blue}{2}}{4 \cdot 4}} \cdot \left(1 - v \cdot v\right) \]
    16. metadata-eval100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{2}{\color{blue}{16}}} \cdot \left(1 - v \cdot v\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot 0.125}} \cdot \left(1 - v \cdot v\right) \]
  5. Taylor expanded in v around 0 98.4%

    \[\leadsto \color{blue}{\sqrt{0.125}} \cdot \left(1 - v \cdot v\right) \]
  6. Add Preprocessing

Alternative 6: 98.9% accurate, 2.1× speedup?

\[\begin{array}{l} \\ \sqrt{0.125} \end{array} \]
(FPCore (v) :precision binary64 (sqrt 0.125))
double code(double v) {
	return sqrt(0.125);
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt(0.125d0)
end function
public static double code(double v) {
	return Math.sqrt(0.125);
}
def code(v):
	return math.sqrt(0.125)
function code(v)
	return sqrt(0.125)
end
function tmp = code(v)
	tmp = sqrt(0.125);
end
code[v_] := N[Sqrt[0.125], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.125}
\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. add-sqr-sqrt98.5%

      \[\leadsto \color{blue}{\left(\sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}} \cdot \sqrt{\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}}\right)} \cdot \left(1 - v \cdot v\right) \]
    2. sqrt-unprod100.0%

      \[\leadsto \color{blue}{\sqrt{\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)}} \cdot \left(1 - v \cdot v\right) \]
    3. *-commutative100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right)} \cdot \left(1 - v \cdot v\right) \]
    4. *-commutative100.0%

      \[\leadsto \sqrt{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right) \cdot \color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    5. swap-sqr100.0%

      \[\leadsto \sqrt{\color{blue}{\left(\sqrt{1 - 3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)}} \cdot \left(1 - v \cdot v\right) \]
    6. add-sqr-sqrt99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    7. sub-neg99.9%

      \[\leadsto \sqrt{\color{blue}{\left(1 + \left(-3 \cdot \left(v \cdot v\right)\right)\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    8. +-commutative99.9%

      \[\leadsto \sqrt{\color{blue}{\left(\left(-3 \cdot \left(v \cdot v\right)\right) + 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    9. *-commutative99.9%

      \[\leadsto \sqrt{\left(\left(-\color{blue}{\left(v \cdot v\right) \cdot 3}\right) + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    10. distribute-rgt-neg-in99.9%

      \[\leadsto \sqrt{\left(\color{blue}{\left(v \cdot v\right) \cdot \left(-3\right)} + 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    11. fma-define99.9%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, -3, 1\right)} \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    12. pow299.9%

      \[\leadsto \sqrt{\mathsf{fma}\left(\color{blue}{{v}^{2}}, -3, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    13. metadata-eval99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, \color{blue}{-3}, 1\right) \cdot \left(\frac{\sqrt{2}}{4} \cdot \frac{\sqrt{2}}{4}\right)} \cdot \left(1 - v \cdot v\right) \]
    14. frac-times99.9%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \color{blue}{\frac{\sqrt{2} \cdot \sqrt{2}}{4 \cdot 4}}} \cdot \left(1 - v \cdot v\right) \]
    15. rem-square-sqrt100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{\color{blue}{2}}{4 \cdot 4}} \cdot \left(1 - v \cdot v\right) \]
    16. metadata-eval100.0%

      \[\leadsto \sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot \frac{2}{\color{blue}{16}}} \cdot \left(1 - v \cdot v\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\sqrt{\mathsf{fma}\left({v}^{2}, -3, 1\right) \cdot 0.125}} \cdot \left(1 - v \cdot v\right) \]
  5. Taylor expanded in v around 0 98.4%

    \[\leadsto \color{blue}{\sqrt{0.125}} \cdot \left(1 - v \cdot v\right) \]
  6. Taylor expanded in v around 0 98.4%

    \[\leadsto \color{blue}{\sqrt{0.125}} \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024111 
(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))))