Falkner and Boettcher, Appendix B, 2

Percentage Accurate: 100.0% → 100.0%
Time: 6.8s
Alternatives: 5
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 5 alternatives:

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

Initial Program: 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, 0.5× speedup?

\[\begin{array}{l} \\ \sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(7 + {v}^{2} \cdot -3\right) - 5\right)\right)} \end{array} \]
(FPCore (v)
 :precision binary64
 (sqrt
  (*
   0.125
   (+
    1.0
    (* (pow v 2.0) (- (* (pow v 2.0) (+ 7.0 (* (pow v 2.0) -3.0))) 5.0))))))
double code(double v) {
	return sqrt((0.125 * (1.0 + (pow(v, 2.0) * ((pow(v, 2.0) * (7.0 + (pow(v, 2.0) * -3.0))) - 5.0)))));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = sqrt((0.125d0 * (1.0d0 + ((v ** 2.0d0) * (((v ** 2.0d0) * (7.0d0 + ((v ** 2.0d0) * (-3.0d0)))) - 5.0d0)))))
end function
public static double code(double v) {
	return Math.sqrt((0.125 * (1.0 + (Math.pow(v, 2.0) * ((Math.pow(v, 2.0) * (7.0 + (Math.pow(v, 2.0) * -3.0))) - 5.0)))));
}
def code(v):
	return math.sqrt((0.125 * (1.0 + (math.pow(v, 2.0) * ((math.pow(v, 2.0) * (7.0 + (math.pow(v, 2.0) * -3.0))) - 5.0)))))
function code(v)
	return sqrt(Float64(0.125 * Float64(1.0 + Float64((v ^ 2.0) * Float64(Float64((v ^ 2.0) * Float64(7.0 + Float64((v ^ 2.0) * -3.0))) - 5.0)))))
end
function tmp = code(v)
	tmp = sqrt((0.125 * (1.0 + ((v ^ 2.0) * (((v ^ 2.0) * (7.0 + ((v ^ 2.0) * -3.0))) - 5.0)))));
end
code[v_] := N[Sqrt[N[(0.125 * N[(1.0 + N[(N[Power[v, 2.0], $MachinePrecision] * N[(N[(N[Power[v, 2.0], $MachinePrecision] * N[(7.0 + N[(N[Power[v, 2.0], $MachinePrecision] * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 5.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(7 + {v}^{2} \cdot -3\right) - 5\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*100.0%

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

      \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 - 3 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}} \cdot \left(1 - v \cdot v\right)\right) \]
    3. cancel-sign-sub-inv100.0%

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

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

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

    \[\leadsto \color{blue}{\frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. add-sqr-sqrt98.4%

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

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

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

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

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

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

      \[\leadsto \sqrt{\color{blue}{0.125} \cdot \left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right) \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    8. swap-sqr100.0%

      \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 + -3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
    9. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(1 + -3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    10. +-commutative100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(-3 \cdot \left(v \cdot v\right) + 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    11. fma-define100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\mathsf{fma}\left(-3, v \cdot v, 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    12. pow2100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, \color{blue}{{v}^{2}}, 1\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    13. pow2100.0%

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

    \[\leadsto \color{blue}{\sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, {v}^{2}, 1\right) \cdot {\left(1 - {v}^{2}\right)}^{2}\right)}} \]
  7. Taylor expanded in v around 0 100.0%

    \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(7 + -3 \cdot {v}^{2}\right) - 5\right)\right)}} \]
  8. Final simplification100.0%

    \[\leadsto \sqrt{0.125 \cdot \left(1 + {v}^{2} \cdot \left({v}^{2} \cdot \left(7 + {v}^{2} \cdot -3\right) - 5\right)\right)} \]
  9. Add Preprocessing

Alternative 2: 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}
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. Final simplification100.0%

    \[\leadsto \left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right) \]
  4. Add Preprocessing

Alternative 3: 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. Step-by-step derivation
    1. associate-*l*100.0%

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

      \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 - 3 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}} \cdot \left(1 - v \cdot v\right)\right) \]
    3. cancel-sign-sub-inv100.0%

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

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

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

    \[\leadsto \color{blue}{\frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in v around 0 99.7%

    \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\color{blue}{\left(1 + -1.5 \cdot {v}^{2}\right)} \cdot \left(1 - v \cdot v\right)\right) \]
  6. Step-by-step derivation
    1. *-commutative99.7%

      \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\left(1 + \color{blue}{{v}^{2} \cdot -1.5}\right) \cdot \left(1 - v \cdot v\right)\right) \]
  7. Simplified99.7%

    \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\color{blue}{\left(1 + {v}^{2} \cdot -1.5\right)} \cdot \left(1 - v \cdot v\right)\right) \]
  8. Taylor expanded in v around 0 99.7%

    \[\leadsto \color{blue}{-0.625 \cdot \left({v}^{2} \cdot \sqrt{2}\right) + 0.25 \cdot \sqrt{2}} \]
  9. Step-by-step derivation
    1. +-commutative99.7%

      \[\leadsto \color{blue}{0.25 \cdot \sqrt{2} + -0.625 \cdot \left({v}^{2} \cdot \sqrt{2}\right)} \]
    2. associate-*r*99.7%

      \[\leadsto 0.25 \cdot \sqrt{2} + \color{blue}{\left(-0.625 \cdot {v}^{2}\right) \cdot \sqrt{2}} \]
    3. distribute-rgt-out99.7%

      \[\leadsto \color{blue}{\sqrt{2} \cdot \left(0.25 + -0.625 \cdot {v}^{2}\right)} \]
    4. *-commutative99.7%

      \[\leadsto \sqrt{2} \cdot \left(0.25 + \color{blue}{{v}^{2} \cdot -0.625}\right) \]
  10. Simplified99.7%

    \[\leadsto \color{blue}{\sqrt{2} \cdot \left(0.25 + {v}^{2} \cdot -0.625\right)} \]
  11. Final simplification99.7%

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

Alternative 4: 99.5% accurate, 1.1× speedup?

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

\\
\sqrt{0.125 + {v}^{2} \cdot -0.625}
\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*100.0%

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

      \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 - 3 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}} \cdot \left(1 - v \cdot v\right)\right) \]
    3. cancel-sign-sub-inv100.0%

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

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

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

    \[\leadsto \color{blue}{\frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. add-sqr-sqrt98.4%

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

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

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

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

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

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

      \[\leadsto \sqrt{\color{blue}{0.125} \cdot \left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right) \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    8. swap-sqr100.0%

      \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 + -3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
    9. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(1 + -3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    10. +-commutative100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(-3 \cdot \left(v \cdot v\right) + 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    11. fma-define100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\mathsf{fma}\left(-3, v \cdot v, 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    12. pow2100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, \color{blue}{{v}^{2}}, 1\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    13. pow2100.0%

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

    \[\leadsto \color{blue}{\sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, {v}^{2}, 1\right) \cdot {\left(1 - {v}^{2}\right)}^{2}\right)}} \]
  7. Taylor expanded in v around 0 99.6%

    \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(1 + -5 \cdot {v}^{2}\right)}} \]
  8. Step-by-step derivation
    1. *-un-lft-identity99.6%

      \[\leadsto \color{blue}{1 \cdot \sqrt{0.125 \cdot \left(1 + -5 \cdot {v}^{2}\right)}} \]
    2. distribute-rgt-in99.6%

      \[\leadsto 1 \cdot \sqrt{\color{blue}{1 \cdot 0.125 + \left(-5 \cdot {v}^{2}\right) \cdot 0.125}} \]
    3. metadata-eval99.6%

      \[\leadsto 1 \cdot \sqrt{\color{blue}{0.125} + \left(-5 \cdot {v}^{2}\right) \cdot 0.125} \]
    4. *-commutative99.6%

      \[\leadsto 1 \cdot \sqrt{0.125 + \color{blue}{\left({v}^{2} \cdot -5\right)} \cdot 0.125} \]
    5. associate-*l*99.6%

      \[\leadsto 1 \cdot \sqrt{0.125 + \color{blue}{{v}^{2} \cdot \left(-5 \cdot 0.125\right)}} \]
    6. metadata-eval99.6%

      \[\leadsto 1 \cdot \sqrt{0.125 + {v}^{2} \cdot \color{blue}{-0.625}} \]
  9. Applied egg-rr99.6%

    \[\leadsto \color{blue}{1 \cdot \sqrt{0.125 + {v}^{2} \cdot -0.625}} \]
  10. Step-by-step derivation
    1. *-lft-identity99.6%

      \[\leadsto \color{blue}{\sqrt{0.125 + {v}^{2} \cdot -0.625}} \]
  11. Simplified99.6%

    \[\leadsto \color{blue}{\sqrt{0.125 + {v}^{2} \cdot -0.625}} \]
  12. Final simplification99.6%

    \[\leadsto \sqrt{0.125 + {v}^{2} \cdot -0.625} \]
  13. Add Preprocessing

Alternative 5: 99.0% 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. Step-by-step derivation
    1. associate-*l*100.0%

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

      \[\leadsto \frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 - 3 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}} \cdot \left(1 - v \cdot v\right)\right) \]
    3. cancel-sign-sub-inv100.0%

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

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

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

    \[\leadsto \color{blue}{\frac{\sqrt{2}}{4} \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. add-sqr-sqrt98.4%

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

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

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

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

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

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

      \[\leadsto \sqrt{\color{blue}{0.125} \cdot \left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right) \cdot \left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    8. swap-sqr100.0%

      \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(\left(\sqrt{1 + -3 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 + -3 \cdot \left(v \cdot v\right)}\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
    9. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(1 + -3 \cdot \left(v \cdot v\right)\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    10. +-commutative100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\left(-3 \cdot \left(v \cdot v\right) + 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    11. fma-define100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\color{blue}{\mathsf{fma}\left(-3, v \cdot v, 1\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    12. pow2100.0%

      \[\leadsto \sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, \color{blue}{{v}^{2}}, 1\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \left(1 - v \cdot v\right)\right)\right)} \]
    13. pow2100.0%

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

    \[\leadsto \color{blue}{\sqrt{0.125 \cdot \left(\mathsf{fma}\left(-3, {v}^{2}, 1\right) \cdot {\left(1 - {v}^{2}\right)}^{2}\right)}} \]
  7. Taylor expanded in v around 0 99.6%

    \[\leadsto \sqrt{0.125 \cdot \color{blue}{\left(1 + -5 \cdot {v}^{2}\right)}} \]
  8. Taylor expanded in v around 0 99.0%

    \[\leadsto \color{blue}{\sqrt{0.125}} \]
  9. Final simplification99.0%

    \[\leadsto \sqrt{0.125} \]
  10. Add Preprocessing

Reproduce

?
herbie shell --seed 2024076 
(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))))