Migdal et al, Equation (51)

Percentage Accurate: 99.4% → 99.5%
Time: 11.7s
Alternatives: 10
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 PI) n) (/ (- 1.0 k) 2.0))))
double code(double k, double n) {
	return (1.0 / sqrt(k)) * pow(((2.0 * ((double) M_PI)) * n), ((1.0 - k) / 2.0));
}
public static double code(double k, double n) {
	return (1.0 / Math.sqrt(k)) * Math.pow(((2.0 * Math.PI) * n), ((1.0 - k) / 2.0));
}
def code(k, n):
	return (1.0 / math.sqrt(k)) * math.pow(((2.0 * math.pi) * n), ((1.0 - k) / 2.0))
function code(k, n)
	return Float64(Float64(1.0 / sqrt(k)) * (Float64(Float64(2.0 * pi) * n) ^ Float64(Float64(1.0 - k) / 2.0)))
end
function tmp = code(k, n)
	tmp = (1.0 / sqrt(k)) * (((2.0 * pi) * n) ^ ((1.0 - k) / 2.0));
end
code[k_, n_] := N[(N[(1.0 / N[Sqrt[k], $MachinePrecision]), $MachinePrecision] * N[Power[N[(N[(2.0 * Pi), $MachinePrecision] * n), $MachinePrecision], N[(N[(1.0 - k), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\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 10 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: 99.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 PI) n) (/ (- 1.0 k) 2.0))))
double code(double k, double n) {
	return (1.0 / sqrt(k)) * pow(((2.0 * ((double) M_PI)) * n), ((1.0 - k) / 2.0));
}
public static double code(double k, double n) {
	return (1.0 / Math.sqrt(k)) * Math.pow(((2.0 * Math.PI) * n), ((1.0 - k) / 2.0));
}
def code(k, n):
	return (1.0 / math.sqrt(k)) * math.pow(((2.0 * math.pi) * n), ((1.0 - k) / 2.0))
function code(k, n)
	return Float64(Float64(1.0 / sqrt(k)) * (Float64(Float64(2.0 * pi) * n) ^ Float64(Float64(1.0 - k) / 2.0)))
end
function tmp = code(k, n)
	tmp = (1.0 / sqrt(k)) * (((2.0 * pi) * n) ^ ((1.0 - k) / 2.0));
end
code[k_, n_] := N[(N[(1.0 / N[Sqrt[k], $MachinePrecision]), $MachinePrecision] * N[Power[N[(N[(2.0 * Pi), $MachinePrecision] * n), $MachinePrecision], N[(N[(1.0 - k), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}
\end{array}

Alternative 1: 99.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (sqrt (* 2.0 n)) (sqrt (/ PI (* k (pow (* (* 2.0 n) PI) k))))))
double code(double k, double n) {
	return sqrt((2.0 * n)) * sqrt((((double) M_PI) / (k * pow(((2.0 * n) * ((double) M_PI)), k))));
}
public static double code(double k, double n) {
	return Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / (k * Math.pow(((2.0 * n) * Math.PI), k))));
}
def code(k, n):
	return math.sqrt((2.0 * n)) * math.sqrt((math.pi / (k * math.pow(((2.0 * n) * math.pi), k))))
function code(k, n)
	return Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / Float64(k * (Float64(Float64(2.0 * n) * pi) ^ k)))))
end
function tmp = code(k, n)
	tmp = sqrt((2.0 * n)) * sqrt((pi / (k * (((2.0 * n) * pi) ^ k))));
end
code[k_, n_] := N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / N[(k * N[Power[N[(N[(2.0 * n), $MachinePrecision] * Pi), $MachinePrecision], k], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}}
\end{array}
Derivation
  1. Initial program 99.3%

    \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-sqrt.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\sqrt{k}}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. frac-2negN/A

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

      \[\leadsto \frac{\color{blue}{-1}}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    4. lift-PI.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \color{blue}{\mathsf{PI}\left(\right)}\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\color{blue}{\left(2 \cdot \mathsf{PI}\left(\right)\right)} \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    6. lift-*.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\color{blue}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}}^{\left(\frac{1 - k}{2}\right)} \]
    7. lift--.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{\color{blue}{1 - k}}{2}\right)} \]
    8. lift-/.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{1 - k}{2}\right)}} \]
    9. lift-pow.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot \color{blue}{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}} \]
    10. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{-1 \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}}{\mathsf{neg}\left(\sqrt{k}\right)}} \]
    11. neg-mul-1N/A

      \[\leadsto \frac{\color{blue}{\mathsf{neg}\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\right)}}{\mathsf{neg}\left(\sqrt{k}\right)} \]
    12. frac-2negN/A

      \[\leadsto \color{blue}{\frac{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}}{\sqrt{k}}} \]
  4. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\frac{\sqrt{2 \cdot \left(\pi \cdot n\right)}}{\sqrt{k} \cdot {\left(2 \cdot \left(\pi \cdot n\right)\right)}^{\left(k \cdot 0.5\right)}}} \]
  5. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\frac{\sqrt{\pi \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot {\left(\pi \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
  6. Step-by-step derivation
    1. lift-PI.f64N/A

      \[\leadsto \frac{\sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}} \]
    2. lift-*.f64N/A

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

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

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot {\left(\color{blue}{\mathsf{PI}\left(\right)} \cdot \left(2 \cdot n\right)\right)}^{k}}} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \color{blue}{\left(2 \cdot n\right)}\right)}^{k}}} \]
    6. lift-*.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot {\color{blue}{\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}}^{k}}} \]
    7. lift-pow.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{\sqrt{k \cdot \color{blue}{{\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
    8. lift-*.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{\sqrt{\color{blue}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
    9. sqrt-undivN/A

      \[\leadsto \color{blue}{\sqrt{\frac{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
    10. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)}}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}} \]
    11. *-commutativeN/A

      \[\leadsto \sqrt{\frac{\color{blue}{\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)}}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}} \]
    12. associate-/l*N/A

      \[\leadsto \sqrt{\color{blue}{\left(2 \cdot n\right) \cdot \frac{\mathsf{PI}\left(\right)}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
    13. sqrt-prodN/A

      \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\mathsf{PI}\left(\right)}{k \cdot {\left(\mathsf{PI}\left(\right) \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
  7. Applied egg-rr99.7%

    \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k \cdot {\left(\pi \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
  8. Final simplification99.7%

    \[\leadsto \sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}} \]
  9. Add Preprocessing

Alternative 2: 67.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{1}{\sqrt{k}} \cdot {\left(n \cdot \left(2 \cdot \pi\right)\right)}^{\left(\frac{1 - k}{2}\right)} \leq 0:\\ \;\;\;\;{\left(\frac{1}{\left(k \cdot k\right) \cdot \left(k \cdot k\right)}\right)}^{0.125}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= (* (/ 1.0 (sqrt k)) (pow (* n (* 2.0 PI)) (/ (- 1.0 k) 2.0))) 0.0)
   (pow (/ 1.0 (* (* k k) (* k k))) 0.125)
   (* (sqrt (* 2.0 n)) (sqrt (/ PI k)))))
double code(double k, double n) {
	double tmp;
	if (((1.0 / sqrt(k)) * pow((n * (2.0 * ((double) M_PI))), ((1.0 - k) / 2.0))) <= 0.0) {
		tmp = pow((1.0 / ((k * k) * (k * k))), 0.125);
	} else {
		tmp = sqrt((2.0 * n)) * sqrt((((double) M_PI) / k));
	}
	return tmp;
}
public static double code(double k, double n) {
	double tmp;
	if (((1.0 / Math.sqrt(k)) * Math.pow((n * (2.0 * Math.PI)), ((1.0 - k) / 2.0))) <= 0.0) {
		tmp = Math.pow((1.0 / ((k * k) * (k * k))), 0.125);
	} else {
		tmp = Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / k));
	}
	return tmp;
}
def code(k, n):
	tmp = 0
	if ((1.0 / math.sqrt(k)) * math.pow((n * (2.0 * math.pi)), ((1.0 - k) / 2.0))) <= 0.0:
		tmp = math.pow((1.0 / ((k * k) * (k * k))), 0.125)
	else:
		tmp = math.sqrt((2.0 * n)) * math.sqrt((math.pi / k))
	return tmp
function code(k, n)
	tmp = 0.0
	if (Float64(Float64(1.0 / sqrt(k)) * (Float64(n * Float64(2.0 * pi)) ^ Float64(Float64(1.0 - k) / 2.0))) <= 0.0)
		tmp = Float64(1.0 / Float64(Float64(k * k) * Float64(k * k))) ^ 0.125;
	else
		tmp = Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / k)));
	end
	return tmp
end
function tmp_2 = code(k, n)
	tmp = 0.0;
	if (((1.0 / sqrt(k)) * ((n * (2.0 * pi)) ^ ((1.0 - k) / 2.0))) <= 0.0)
		tmp = (1.0 / ((k * k) * (k * k))) ^ 0.125;
	else
		tmp = sqrt((2.0 * n)) * sqrt((pi / k));
	end
	tmp_2 = tmp;
end
code[k_, n_] := If[LessEqual[N[(N[(1.0 / N[Sqrt[k], $MachinePrecision]), $MachinePrecision] * N[Power[N[(n * N[(2.0 * Pi), $MachinePrecision]), $MachinePrecision], N[(N[(1.0 - k), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 0.0], N[Power[N[(1.0 / N[(N[(k * k), $MachinePrecision] * N[(k * k), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 0.125], $MachinePrecision], N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / k), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{1}{\sqrt{k}} \cdot {\left(n \cdot \left(2 \cdot \pi\right)\right)}^{\left(\frac{1 - k}{2}\right)} \leq 0:\\
\;\;\;\;{\left(\frac{1}{\left(k \cdot k\right) \cdot \left(k \cdot k\right)}\right)}^{0.125}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 (/.f64 #s(literal 1 binary64) (sqrt.f64 k)) (pow.f64 (*.f64 (*.f64 #s(literal 2 binary64) (PI.f64)) n) (/.f64 (-.f64 #s(literal 1 binary64) k) #s(literal 2 binary64)))) < 0.0

    1. Initial program 100.0%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in k around inf

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{-1}{2} \cdot k\right)}} \]
    4. Step-by-step derivation
      1. lower-*.f64100.0

        \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    5. Simplified100.0%

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    6. Taylor expanded in k around 0

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    7. Step-by-step derivation
      1. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
      2. lower-/.f643.8

        \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
    8. Simplified3.8%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    9. Step-by-step derivation
      1. sqrt-divN/A

        \[\leadsto \color{blue}{\frac{\sqrt{1}}{\sqrt{k}}} \]
      2. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{k}} \]
      3. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{\color{blue}{\sqrt{k}}} \]
      4. lower-/.f643.8

        \[\leadsto \color{blue}{\frac{1}{\sqrt{k}}} \]
    10. Applied egg-rr3.8%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{k}}} \]
    11. Step-by-step derivation
      1. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{\sqrt{1}}}{\sqrt{k}} \]
      2. sqrt-divN/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
      3. lift-/.f64N/A

        \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
      4. pow1/2N/A

        \[\leadsto \color{blue}{{\left(\frac{1}{k}\right)}^{\frac{1}{2}}} \]
      5. metadata-evalN/A

        \[\leadsto {\left(\frac{1}{k}\right)}^{\color{blue}{\left(2 \cdot \frac{1}{4}\right)}} \]
      6. pow-powN/A

        \[\leadsto \color{blue}{{\left({\left(\frac{1}{k}\right)}^{2}\right)}^{\frac{1}{4}}} \]
      7. pow2N/A

        \[\leadsto {\color{blue}{\left(\frac{1}{k} \cdot \frac{1}{k}\right)}}^{\frac{1}{4}} \]
      8. lift-*.f64N/A

        \[\leadsto {\color{blue}{\left(\frac{1}{k} \cdot \frac{1}{k}\right)}}^{\frac{1}{4}} \]
      9. sqr-powN/A

        \[\leadsto \color{blue}{{\left(\frac{1}{k} \cdot \frac{1}{k}\right)}^{\left(\frac{\frac{1}{4}}{2}\right)} \cdot {\left(\frac{1}{k} \cdot \frac{1}{k}\right)}^{\left(\frac{\frac{1}{4}}{2}\right)}} \]
      10. pow-prod-downN/A

        \[\leadsto \color{blue}{{\left(\left(\frac{1}{k} \cdot \frac{1}{k}\right) \cdot \left(\frac{1}{k} \cdot \frac{1}{k}\right)\right)}^{\left(\frac{\frac{1}{4}}{2}\right)}} \]
      11. lower-pow.f64N/A

        \[\leadsto \color{blue}{{\left(\left(\frac{1}{k} \cdot \frac{1}{k}\right) \cdot \left(\frac{1}{k} \cdot \frac{1}{k}\right)\right)}^{\left(\frac{\frac{1}{4}}{2}\right)}} \]
    12. Applied egg-rr83.6%

      \[\leadsto \color{blue}{{\left(\frac{1}{\left(k \cdot k\right) \cdot \left(k \cdot k\right)}\right)}^{0.125}} \]

    if 0.0 < (*.f64 (/.f64 #s(literal 1 binary64) (sqrt.f64 k)) (pow.f64 (*.f64 (*.f64 #s(literal 2 binary64) (PI.f64)) n) (/.f64 (-.f64 #s(literal 1 binary64) k) #s(literal 2 binary64))))

    1. Initial program 99.1%

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

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

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

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

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

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

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      6. lower-sqrt.f6455.5

        \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
    5. Simplified55.5%

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
    6. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      2. *-commutativeN/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      3. associate-/l*N/A

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

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
      5. lower-/.f6455.5

        \[\leadsto \sqrt{\pi \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
    7. Applied egg-rr55.5%

      \[\leadsto \sqrt{\color{blue}{\pi \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
    8. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \frac{n}{k}} \cdot \sqrt{2} \]
      2. lift-/.f64N/A

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

        \[\leadsto \sqrt{\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
      4. associate-*r/N/A

        \[\leadsto \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \cdot \sqrt{2} \]
      5. lift-*.f64N/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      6. sqrt-undivN/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}}} \cdot \sqrt{2} \]
      7. lift-sqrt.f64N/A

        \[\leadsto \frac{\color{blue}{\sqrt{\mathsf{PI}\left(\right) \cdot n}}}{\sqrt{k}} \cdot \sqrt{2} \]
      8. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{k}}} \cdot \sqrt{2} \]
      9. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}} \cdot \color{blue}{\sqrt{2}} \]
      10. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}}{\sqrt{k}}} \]
      11. div-invN/A

        \[\leadsto \color{blue}{\left(\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}\right) \cdot \frac{1}{\sqrt{k}}} \]
    9. Applied egg-rr73.1%

      \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification75.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1}{\sqrt{k}} \cdot {\left(n \cdot \left(2 \cdot \pi\right)\right)}^{\left(\frac{1 - k}{2}\right)} \leq 0:\\ \;\;\;\;{\left(\frac{1}{\left(k \cdot k\right) \cdot \left(k \cdot k\right)}\right)}^{0.125}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 97.9% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;k \leq 1:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\sqrt{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= k 1.0)
   (* (sqrt (* 2.0 n)) (sqrt (/ PI k)))
   (/ 1.0 (sqrt (* k (pow (* (* 2.0 n) PI) k))))))
double code(double k, double n) {
	double tmp;
	if (k <= 1.0) {
		tmp = sqrt((2.0 * n)) * sqrt((((double) M_PI) / k));
	} else {
		tmp = 1.0 / sqrt((k * pow(((2.0 * n) * ((double) M_PI)), k)));
	}
	return tmp;
}
public static double code(double k, double n) {
	double tmp;
	if (k <= 1.0) {
		tmp = Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / k));
	} else {
		tmp = 1.0 / Math.sqrt((k * Math.pow(((2.0 * n) * Math.PI), k)));
	}
	return tmp;
}
def code(k, n):
	tmp = 0
	if k <= 1.0:
		tmp = math.sqrt((2.0 * n)) * math.sqrt((math.pi / k))
	else:
		tmp = 1.0 / math.sqrt((k * math.pow(((2.0 * n) * math.pi), k)))
	return tmp
function code(k, n)
	tmp = 0.0
	if (k <= 1.0)
		tmp = Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / k)));
	else
		tmp = Float64(1.0 / sqrt(Float64(k * (Float64(Float64(2.0 * n) * pi) ^ k))));
	end
	return tmp
end
function tmp_2 = code(k, n)
	tmp = 0.0;
	if (k <= 1.0)
		tmp = sqrt((2.0 * n)) * sqrt((pi / k));
	else
		tmp = 1.0 / sqrt((k * (((2.0 * n) * pi) ^ k)));
	end
	tmp_2 = tmp;
end
code[k_, n_] := If[LessEqual[k, 1.0], N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / k), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 / N[Sqrt[N[(k * N[Power[N[(N[(2.0 * n), $MachinePrecision] * Pi), $MachinePrecision], k], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;k \leq 1:\\
\;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{\sqrt{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if k < 1

    1. Initial program 98.8%

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

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

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

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

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

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

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      6. lower-sqrt.f6473.7

        \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
    5. Simplified73.7%

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
    6. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      2. *-commutativeN/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      3. associate-/l*N/A

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

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
      5. lower-/.f6473.7

        \[\leadsto \sqrt{\pi \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
    7. Applied egg-rr73.7%

      \[\leadsto \sqrt{\color{blue}{\pi \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
    8. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \frac{n}{k}} \cdot \sqrt{2} \]
      2. lift-/.f64N/A

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

        \[\leadsto \sqrt{\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
      4. associate-*r/N/A

        \[\leadsto \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \cdot \sqrt{2} \]
      5. lift-*.f64N/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      6. sqrt-undivN/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}}} \cdot \sqrt{2} \]
      7. lift-sqrt.f64N/A

        \[\leadsto \frac{\color{blue}{\sqrt{\mathsf{PI}\left(\right) \cdot n}}}{\sqrt{k}} \cdot \sqrt{2} \]
      8. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{k}}} \cdot \sqrt{2} \]
      9. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}} \cdot \color{blue}{\sqrt{2}} \]
      10. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}}{\sqrt{k}}} \]
      11. div-invN/A

        \[\leadsto \color{blue}{\left(\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}\right) \cdot \frac{1}{\sqrt{k}}} \]
    9. Applied egg-rr97.2%

      \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}} \]

    if 1 < k

    1. Initial program 100.0%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in k around inf

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{-1}{2} \cdot k\right)}} \]
    4. Step-by-step derivation
      1. lower-*.f64100.0

        \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    5. Simplified100.0%

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    6. Step-by-step derivation
      1. pow1/2N/A

        \[\leadsto \frac{1}{\color{blue}{{k}^{\frac{1}{2}}}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{-1}{2} \cdot k\right)} \]
      2. pow-flipN/A

        \[\leadsto \color{blue}{{k}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{-1}{2} \cdot k\right)} \]
      3. metadata-evalN/A

        \[\leadsto {k}^{\color{blue}{\frac{-1}{2}}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{-1}{2} \cdot k\right)} \]
      4. lift-PI.f64N/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\left(\left(2 \cdot \color{blue}{\mathsf{PI}\left(\right)}\right) \cdot n\right)}^{\left(\frac{-1}{2} \cdot k\right)} \]
      5. associate-*r*N/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\color{blue}{\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}}^{\left(\frac{-1}{2} \cdot k\right)} \]
      6. lift-*.f64N/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\left(2 \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot n\right)}\right)}^{\left(\frac{-1}{2} \cdot k\right)} \]
      7. lift-*.f64N/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\color{blue}{\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}}^{\left(\frac{-1}{2} \cdot k\right)} \]
      8. rem-exp-logN/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\color{blue}{\left(e^{\log \left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}\right)}}^{\left(\frac{-1}{2} \cdot k\right)} \]
      9. rem-exp-logN/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\color{blue}{\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}}^{\left(\frac{-1}{2} \cdot k\right)} \]
      10. *-commutativeN/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot {\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{\color{blue}{\left(k \cdot \frac{-1}{2}\right)}} \]
      11. pow-unpowN/A

        \[\leadsto {k}^{\frac{-1}{2}} \cdot \color{blue}{{\left({\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{-1}{2}}} \]
      12. pow-prod-downN/A

        \[\leadsto \color{blue}{{\left(k \cdot {\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{-1}{2}}} \]
      13. metadata-evalN/A

        \[\leadsto {\left(k \cdot {\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \]
      14. pow-flipN/A

        \[\leadsto \color{blue}{\frac{1}{{\left(k \cdot {\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{1}{2}}}} \]
      15. pow-prod-downN/A

        \[\leadsto \frac{1}{\color{blue}{{k}^{\frac{1}{2}} \cdot {\left({\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{1}{2}}}} \]
      16. pow1/2N/A

        \[\leadsto \frac{1}{\color{blue}{\sqrt{k}} \cdot {\left({\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{1}{2}}} \]
      17. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{\color{blue}{\sqrt{k}} \cdot {\left({\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{k}\right)}^{\frac{1}{2}}} \]
      18. pow-unpowN/A

        \[\leadsto \frac{1}{\sqrt{k} \cdot \color{blue}{{\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{\left(k \cdot \frac{1}{2}\right)}}} \]
      19. lift-*.f64N/A

        \[\leadsto \frac{1}{\sqrt{k} \cdot {\left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)\right)}^{\color{blue}{\left(k \cdot \frac{1}{2}\right)}}} \]
    7. Applied egg-rr100.0%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{k \cdot {\left(\pi \cdot \left(2 \cdot n\right)\right)}^{k}}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;k \leq 1:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\sqrt{k \cdot {\left(\left(2 \cdot n\right) \cdot \pi\right)}^{k}}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.5% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{{\left(\left(2 \cdot n\right) \cdot \pi\right)}^{\left(\mathsf{fma}\left(k, -0.5, 0.5\right)\right)}}{\sqrt{k}} \end{array} \]
(FPCore (k n)
 :precision binary64
 (/ (pow (* (* 2.0 n) PI) (fma k -0.5 0.5)) (sqrt k)))
double code(double k, double n) {
	return pow(((2.0 * n) * ((double) M_PI)), fma(k, -0.5, 0.5)) / sqrt(k);
}
function code(k, n)
	return Float64((Float64(Float64(2.0 * n) * pi) ^ fma(k, -0.5, 0.5)) / sqrt(k))
end
code[k_, n_] := N[(N[Power[N[(N[(2.0 * n), $MachinePrecision] * Pi), $MachinePrecision], N[(k * -0.5 + 0.5), $MachinePrecision]], $MachinePrecision] / N[Sqrt[k], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{{\left(\left(2 \cdot n\right) \cdot \pi\right)}^{\left(\mathsf{fma}\left(k, -0.5, 0.5\right)\right)}}{\sqrt{k}}
\end{array}
Derivation
  1. Initial program 99.3%

    \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-sqrt.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\sqrt{k}}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. frac-2negN/A

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

      \[\leadsto \frac{\color{blue}{-1}}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    4. lift-PI.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \color{blue}{\mathsf{PI}\left(\right)}\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    5. lift-*.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\color{blue}{\left(2 \cdot \mathsf{PI}\left(\right)\right)} \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    6. lift-*.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\color{blue}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}}^{\left(\frac{1 - k}{2}\right)} \]
    7. lift--.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{\color{blue}{1 - k}}{2}\right)} \]
    8. lift-/.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{1 - k}{2}\right)}} \]
    9. lift-pow.f64N/A

      \[\leadsto \frac{-1}{\mathsf{neg}\left(\sqrt{k}\right)} \cdot \color{blue}{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}} \]
    10. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{-1 \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}}{\mathsf{neg}\left(\sqrt{k}\right)}} \]
    11. neg-mul-1N/A

      \[\leadsto \frac{\color{blue}{\mathsf{neg}\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\right)}}{\mathsf{neg}\left(\sqrt{k}\right)} \]
    12. frac-2negN/A

      \[\leadsto \color{blue}{\frac{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}}{\sqrt{k}}} \]
  4. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\frac{\sqrt{2 \cdot \left(\pi \cdot n\right)}}{\sqrt{k} \cdot {\left(2 \cdot \left(\pi \cdot n\right)\right)}^{\left(k \cdot 0.5\right)}}} \]
  5. Applied egg-rr99.4%

    \[\leadsto \color{blue}{\frac{{\left(\pi \cdot \left(2 \cdot n\right)\right)}^{\left(\mathsf{fma}\left(k, -0.5, 0.5\right)\right)}}{\sqrt{k}}} \]
  6. Final simplification99.4%

    \[\leadsto \frac{{\left(\left(2 \cdot n\right) \cdot \pi\right)}^{\left(\mathsf{fma}\left(k, -0.5, 0.5\right)\right)}}{\sqrt{k}} \]
  7. Add Preprocessing

Alternative 5: 61.6% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;k \leq 0.495:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \mathbf{else}:\\ \;\;\;\;{\left(k \cdot k\right)}^{-0.25}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= k 0.495) (* (sqrt (* 2.0 n)) (sqrt (/ PI k))) (pow (* k k) -0.25)))
double code(double k, double n) {
	double tmp;
	if (k <= 0.495) {
		tmp = sqrt((2.0 * n)) * sqrt((((double) M_PI) / k));
	} else {
		tmp = pow((k * k), -0.25);
	}
	return tmp;
}
public static double code(double k, double n) {
	double tmp;
	if (k <= 0.495) {
		tmp = Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / k));
	} else {
		tmp = Math.pow((k * k), -0.25);
	}
	return tmp;
}
def code(k, n):
	tmp = 0
	if k <= 0.495:
		tmp = math.sqrt((2.0 * n)) * math.sqrt((math.pi / k))
	else:
		tmp = math.pow((k * k), -0.25)
	return tmp
function code(k, n)
	tmp = 0.0
	if (k <= 0.495)
		tmp = Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / k)));
	else
		tmp = Float64(k * k) ^ -0.25;
	end
	return tmp
end
function tmp_2 = code(k, n)
	tmp = 0.0;
	if (k <= 0.495)
		tmp = sqrt((2.0 * n)) * sqrt((pi / k));
	else
		tmp = (k * k) ^ -0.25;
	end
	tmp_2 = tmp;
end
code[k_, n_] := If[LessEqual[k, 0.495], N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / k), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Power[N[(k * k), $MachinePrecision], -0.25], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;k \leq 0.495:\\
\;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\

\mathbf{else}:\\
\;\;\;\;{\left(k \cdot k\right)}^{-0.25}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if k < 0.495

    1. Initial program 98.8%

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

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

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

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

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

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

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      6. lower-sqrt.f6473.7

        \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
    5. Simplified73.7%

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
    6. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      2. *-commutativeN/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      3. associate-/l*N/A

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

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
      5. lower-/.f6473.7

        \[\leadsto \sqrt{\pi \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
    7. Applied egg-rr73.7%

      \[\leadsto \sqrt{\color{blue}{\pi \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
    8. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \frac{n}{k}} \cdot \sqrt{2} \]
      2. lift-/.f64N/A

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

        \[\leadsto \sqrt{\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
      4. associate-*r/N/A

        \[\leadsto \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \cdot \sqrt{2} \]
      5. lift-*.f64N/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      6. sqrt-undivN/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}}} \cdot \sqrt{2} \]
      7. lift-sqrt.f64N/A

        \[\leadsto \frac{\color{blue}{\sqrt{\mathsf{PI}\left(\right) \cdot n}}}{\sqrt{k}} \cdot \sqrt{2} \]
      8. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{k}}} \cdot \sqrt{2} \]
      9. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}} \cdot \color{blue}{\sqrt{2}} \]
      10. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}}{\sqrt{k}}} \]
      11. div-invN/A

        \[\leadsto \color{blue}{\left(\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}\right) \cdot \frac{1}{\sqrt{k}}} \]
    9. Applied egg-rr97.2%

      \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}} \]

    if 0.495 < k

    1. Initial program 100.0%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in k around inf

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{-1}{2} \cdot k\right)}} \]
    4. Step-by-step derivation
      1. lower-*.f64100.0

        \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    5. Simplified100.0%

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    6. Taylor expanded in k around 0

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    7. Step-by-step derivation
      1. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
      2. lower-/.f643.3

        \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
    8. Simplified3.3%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    9. Step-by-step derivation
      1. sqrt-divN/A

        \[\leadsto \color{blue}{\frac{\sqrt{1}}{\sqrt{k}}} \]
      2. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{k}} \]
      3. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{\color{blue}{\sqrt{k}}} \]
      4. lower-/.f643.3

        \[\leadsto \color{blue}{\frac{1}{\sqrt{k}}} \]
    10. Applied egg-rr3.3%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{k}}} \]
    11. Step-by-step derivation
      1. pow1/2N/A

        \[\leadsto \frac{1}{\color{blue}{{k}^{\frac{1}{2}}}} \]
      2. pow-flipN/A

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

        \[\leadsto {k}^{\color{blue}{\frac{-1}{2}}} \]
      4. metadata-evalN/A

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

        \[\leadsto {k}^{\left(2 \cdot \color{blue}{\left(-1 \cdot \frac{1}{4}\right)}\right)} \]
      6. pow-sqrN/A

        \[\leadsto \color{blue}{{k}^{\left(-1 \cdot \frac{1}{4}\right)} \cdot {k}^{\left(-1 \cdot \frac{1}{4}\right)}} \]
      7. pow-prod-downN/A

        \[\leadsto \color{blue}{{\left(k \cdot k\right)}^{\left(-1 \cdot \frac{1}{4}\right)}} \]
      8. lower-pow.f64N/A

        \[\leadsto \color{blue}{{\left(k \cdot k\right)}^{\left(-1 \cdot \frac{1}{4}\right)}} \]
      9. lower-*.f64N/A

        \[\leadsto {\color{blue}{\left(k \cdot k\right)}}^{\left(-1 \cdot \frac{1}{4}\right)} \]
      10. metadata-eval26.9

        \[\leadsto {\left(k \cdot k\right)}^{\color{blue}{-0.25}} \]
    12. Applied egg-rr26.9%

      \[\leadsto \color{blue}{{\left(k \cdot k\right)}^{-0.25}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 60.8% accurate, 2.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;k \leq 0.495:\\ \;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\sqrt{\frac{1}{k} \cdot \frac{1}{k}}}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= k 0.495)
   (* (sqrt (* 2.0 n)) (sqrt (/ PI k)))
   (sqrt (sqrt (* (/ 1.0 k) (/ 1.0 k))))))
double code(double k, double n) {
	double tmp;
	if (k <= 0.495) {
		tmp = sqrt((2.0 * n)) * sqrt((((double) M_PI) / k));
	} else {
		tmp = sqrt(sqrt(((1.0 / k) * (1.0 / k))));
	}
	return tmp;
}
public static double code(double k, double n) {
	double tmp;
	if (k <= 0.495) {
		tmp = Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / k));
	} else {
		tmp = Math.sqrt(Math.sqrt(((1.0 / k) * (1.0 / k))));
	}
	return tmp;
}
def code(k, n):
	tmp = 0
	if k <= 0.495:
		tmp = math.sqrt((2.0 * n)) * math.sqrt((math.pi / k))
	else:
		tmp = math.sqrt(math.sqrt(((1.0 / k) * (1.0 / k))))
	return tmp
function code(k, n)
	tmp = 0.0
	if (k <= 0.495)
		tmp = Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / k)));
	else
		tmp = sqrt(sqrt(Float64(Float64(1.0 / k) * Float64(1.0 / k))));
	end
	return tmp
end
function tmp_2 = code(k, n)
	tmp = 0.0;
	if (k <= 0.495)
		tmp = sqrt((2.0 * n)) * sqrt((pi / k));
	else
		tmp = sqrt(sqrt(((1.0 / k) * (1.0 / k))));
	end
	tmp_2 = tmp;
end
code[k_, n_] := If[LessEqual[k, 0.495], N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / k), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[N[Sqrt[N[(N[(1.0 / k), $MachinePrecision] * N[(1.0 / k), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;k \leq 0.495:\\
\;\;\;\;\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{\sqrt{\frac{1}{k} \cdot \frac{1}{k}}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if k < 0.495

    1. Initial program 98.8%

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

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

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

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

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

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

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      6. lower-sqrt.f6473.7

        \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
    5. Simplified73.7%

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
    6. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
      2. *-commutativeN/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      3. associate-/l*N/A

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

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
      5. lower-/.f6473.7

        \[\leadsto \sqrt{\pi \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
    7. Applied egg-rr73.7%

      \[\leadsto \sqrt{\color{blue}{\pi \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
    8. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \frac{n}{k}} \cdot \sqrt{2} \]
      2. lift-/.f64N/A

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

        \[\leadsto \sqrt{\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
      4. associate-*r/N/A

        \[\leadsto \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \cdot \sqrt{2} \]
      5. lift-*.f64N/A

        \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
      6. sqrt-undivN/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}}} \cdot \sqrt{2} \]
      7. lift-sqrt.f64N/A

        \[\leadsto \frac{\color{blue}{\sqrt{\mathsf{PI}\left(\right) \cdot n}}}{\sqrt{k}} \cdot \sqrt{2} \]
      8. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{k}}} \cdot \sqrt{2} \]
      9. lift-sqrt.f64N/A

        \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}} \cdot \color{blue}{\sqrt{2}} \]
      10. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}}{\sqrt{k}}} \]
      11. div-invN/A

        \[\leadsto \color{blue}{\left(\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}\right) \cdot \frac{1}{\sqrt{k}}} \]
    9. Applied egg-rr97.2%

      \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}} \]

    if 0.495 < k

    1. Initial program 100.0%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in k around inf

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{-1}{2} \cdot k\right)}} \]
    4. Step-by-step derivation
      1. lower-*.f64100.0

        \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    5. Simplified100.0%

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
    6. Taylor expanded in k around 0

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    7. Step-by-step derivation
      1. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
      2. lower-/.f643.3

        \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
    8. Simplified3.3%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    9. Step-by-step derivation
      1. lift-/.f643.3

        \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
      2. rem-square-sqrtN/A

        \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{k}} \cdot \sqrt{\frac{1}{k}}}} \]
      3. sqrt-unprodN/A

        \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{k} \cdot \frac{1}{k}}}} \]
      4. lower-sqrt.f64N/A

        \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{k} \cdot \frac{1}{k}}}} \]
      5. lower-*.f6425.2

        \[\leadsto \sqrt{\sqrt{\color{blue}{\frac{1}{k} \cdot \frac{1}{k}}}} \]
    10. Applied egg-rr25.2%

      \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{k} \cdot \frac{1}{k}}}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 48.6% accurate, 3.6× speedup?

\[\begin{array}{l} \\ \sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}} \end{array} \]
(FPCore (k n) :precision binary64 (* (sqrt (* 2.0 n)) (sqrt (/ PI k))))
double code(double k, double n) {
	return sqrt((2.0 * n)) * sqrt((((double) M_PI) / k));
}
public static double code(double k, double n) {
	return Math.sqrt((2.0 * n)) * Math.sqrt((Math.PI / k));
}
def code(k, n):
	return math.sqrt((2.0 * n)) * math.sqrt((math.pi / k))
function code(k, n)
	return Float64(sqrt(Float64(2.0 * n)) * sqrt(Float64(pi / k)))
end
function tmp = code(k, n)
	tmp = sqrt((2.0 * n)) * sqrt((pi / k));
end
code[k_, n_] := N[(N[Sqrt[N[(2.0 * n), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(Pi / k), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}
\end{array}
Derivation
  1. Initial program 99.3%

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

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

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

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

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

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

      \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
    6. lower-sqrt.f6443.5

      \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
  5. Simplified43.5%

    \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
  6. Step-by-step derivation
    1. lift-PI.f64N/A

      \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
    2. *-commutativeN/A

      \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
    3. associate-/l*N/A

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

      \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
    5. lower-/.f6443.5

      \[\leadsto \sqrt{\pi \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
  7. Applied egg-rr43.5%

    \[\leadsto \sqrt{\color{blue}{\pi \cdot \frac{n}{k}}} \cdot \sqrt{2} \]
  8. Step-by-step derivation
    1. lift-PI.f64N/A

      \[\leadsto \sqrt{\color{blue}{\mathsf{PI}\left(\right)} \cdot \frac{n}{k}} \cdot \sqrt{2} \]
    2. lift-/.f64N/A

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

      \[\leadsto \sqrt{\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{n}{k}}} \cdot \sqrt{2} \]
    4. associate-*r/N/A

      \[\leadsto \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \cdot \sqrt{2} \]
    5. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \cdot \sqrt{2} \]
    6. sqrt-undivN/A

      \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}}} \cdot \sqrt{2} \]
    7. lift-sqrt.f64N/A

      \[\leadsto \frac{\color{blue}{\sqrt{\mathsf{PI}\left(\right) \cdot n}}}{\sqrt{k}} \cdot \sqrt{2} \]
    8. lift-sqrt.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{k}}} \cdot \sqrt{2} \]
    9. lift-sqrt.f64N/A

      \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{k}} \cdot \color{blue}{\sqrt{2}} \]
    10. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}}{\sqrt{k}}} \]
    11. div-invN/A

      \[\leadsto \color{blue}{\left(\sqrt{\mathsf{PI}\left(\right) \cdot n} \cdot \sqrt{2}\right) \cdot \frac{1}{\sqrt{k}}} \]
  9. Applied egg-rr57.0%

    \[\leadsto \color{blue}{\sqrt{2 \cdot n} \cdot \sqrt{\frac{\pi}{k}}} \]
  10. Add Preprocessing

Alternative 8: 48.5% accurate, 3.6× speedup?

\[\begin{array}{l} \\ \sqrt{n} \cdot \sqrt{2 \cdot \frac{\pi}{k}} \end{array} \]
(FPCore (k n) :precision binary64 (* (sqrt n) (sqrt (* 2.0 (/ PI k)))))
double code(double k, double n) {
	return sqrt(n) * sqrt((2.0 * (((double) M_PI) / k)));
}
public static double code(double k, double n) {
	return Math.sqrt(n) * Math.sqrt((2.0 * (Math.PI / k)));
}
def code(k, n):
	return math.sqrt(n) * math.sqrt((2.0 * (math.pi / k)))
function code(k, n)
	return Float64(sqrt(n) * sqrt(Float64(2.0 * Float64(pi / k))))
end
function tmp = code(k, n)
	tmp = sqrt(n) * sqrt((2.0 * (pi / k)));
end
code[k_, n_] := N[(N[Sqrt[n], $MachinePrecision] * N[Sqrt[N[(2.0 * N[(Pi / k), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\sqrt{n} \cdot \sqrt{2 \cdot \frac{\pi}{k}}
\end{array}
Derivation
  1. Initial program 99.3%

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

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

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

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

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

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

      \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
    6. lower-sqrt.f6443.5

      \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
  5. Simplified43.5%

    \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
  6. Step-by-step derivation
    1. lift-PI.f64N/A

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

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

      \[\leadsto \sqrt{\color{blue}{\frac{n \cdot \mathsf{PI}\left(\right)}{k}}} \cdot \sqrt{2} \]
    4. sqrt-unprodN/A

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \mathsf{PI}\left(\right)}{k} \cdot 2}} \]
    5. lift-/.f64N/A

      \[\leadsto \sqrt{\color{blue}{\frac{n \cdot \mathsf{PI}\left(\right)}{k}} \cdot 2} \]
    6. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{\color{blue}{n \cdot \mathsf{PI}\left(\right)}}{k} \cdot 2} \]
    7. associate-/l*N/A

      \[\leadsto \sqrt{\color{blue}{\left(n \cdot \frac{\mathsf{PI}\left(\right)}{k}\right)} \cdot 2} \]
    8. associate-*l*N/A

      \[\leadsto \sqrt{\color{blue}{n \cdot \left(\frac{\mathsf{PI}\left(\right)}{k} \cdot 2\right)}} \]
    9. sqrt-prodN/A

      \[\leadsto \color{blue}{\sqrt{n} \cdot \sqrt{\frac{\mathsf{PI}\left(\right)}{k} \cdot 2}} \]
    10. unpow1/2N/A

      \[\leadsto \color{blue}{{n}^{\frac{1}{2}}} \cdot \sqrt{\frac{\mathsf{PI}\left(\right)}{k} \cdot 2} \]
    11. lower-*.f64N/A

      \[\leadsto \color{blue}{{n}^{\frac{1}{2}} \cdot \sqrt{\frac{\mathsf{PI}\left(\right)}{k} \cdot 2}} \]
    12. unpow1/2N/A

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

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

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

      \[\leadsto \sqrt{n} \cdot \sqrt{\color{blue}{\frac{\mathsf{PI}\left(\right)}{k} \cdot 2}} \]
    16. lower-/.f6457.0

      \[\leadsto \sqrt{n} \cdot \sqrt{\color{blue}{\frac{\pi}{k}} \cdot 2} \]
  7. Applied egg-rr57.0%

    \[\leadsto \color{blue}{\sqrt{n} \cdot \sqrt{\frac{\pi}{k} \cdot 2}} \]
  8. Final simplification57.0%

    \[\leadsto \sqrt{n} \cdot \sqrt{2 \cdot \frac{\pi}{k}} \]
  9. Add Preprocessing

Alternative 9: 37.1% accurate, 4.8× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{\left(2 \cdot n\right) \cdot \pi}{k}} \end{array} \]
(FPCore (k n) :precision binary64 (sqrt (/ (* (* 2.0 n) PI) k)))
double code(double k, double n) {
	return sqrt((((2.0 * n) * ((double) M_PI)) / k));
}
public static double code(double k, double n) {
	return Math.sqrt((((2.0 * n) * Math.PI) / k));
}
def code(k, n):
	return math.sqrt((((2.0 * n) * math.pi) / k))
function code(k, n)
	return sqrt(Float64(Float64(Float64(2.0 * n) * pi) / k))
end
function tmp = code(k, n)
	tmp = sqrt((((2.0 * n) * pi) / k));
end
code[k_, n_] := N[Sqrt[N[(N[(N[(2.0 * n), $MachinePrecision] * Pi), $MachinePrecision] / k), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\frac{\left(2 \cdot n\right) \cdot \pi}{k}}
\end{array}
Derivation
  1. Initial program 99.3%

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

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

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

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

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

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

      \[\leadsto \sqrt{\frac{n \cdot \color{blue}{\mathsf{PI}\left(\right)}}{k}} \cdot \sqrt{2} \]
    6. lower-sqrt.f6443.5

      \[\leadsto \sqrt{\frac{n \cdot \pi}{k}} \cdot \color{blue}{\sqrt{2}} \]
  5. Simplified43.5%

    \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \pi}{k}} \cdot \sqrt{2}} \]
  6. Step-by-step derivation
    1. lift-PI.f64N/A

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

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

      \[\leadsto \sqrt{\color{blue}{\frac{n \cdot \mathsf{PI}\left(\right)}{k}}} \cdot \sqrt{2} \]
    4. sqrt-unprodN/A

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

      \[\leadsto \color{blue}{\sqrt{\frac{n \cdot \mathsf{PI}\left(\right)}{k} \cdot 2}} \]
    6. lift-/.f64N/A

      \[\leadsto \sqrt{\color{blue}{\frac{n \cdot \mathsf{PI}\left(\right)}{k}} \cdot 2} \]
    7. associate-*l/N/A

      \[\leadsto \sqrt{\color{blue}{\frac{\left(n \cdot \mathsf{PI}\left(\right)\right) \cdot 2}{k}}} \]
    8. *-commutativeN/A

      \[\leadsto \sqrt{\frac{\color{blue}{2 \cdot \left(n \cdot \mathsf{PI}\left(\right)\right)}}{k}} \]
    9. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{2 \cdot \color{blue}{\left(n \cdot \mathsf{PI}\left(\right)\right)}}{k}} \]
    10. *-commutativeN/A

      \[\leadsto \sqrt{\frac{2 \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot n\right)}}{k}} \]
    11. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{2 \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot n\right)}}{k}} \]
    12. lift-*.f64N/A

      \[\leadsto \sqrt{\frac{\color{blue}{2 \cdot \left(\mathsf{PI}\left(\right) \cdot n\right)}}{k}} \]
    13. lower-/.f6443.6

      \[\leadsto \sqrt{\color{blue}{\frac{2 \cdot \left(\pi \cdot n\right)}{k}}} \]
  7. Applied egg-rr43.6%

    \[\leadsto \color{blue}{\sqrt{\frac{\pi \cdot \left(2 \cdot n\right)}{k}}} \]
  8. Final simplification43.6%

    \[\leadsto \sqrt{\frac{\left(2 \cdot n\right) \cdot \pi}{k}} \]
  9. Add Preprocessing

Alternative 10: 5.1% accurate, 6.9× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{1}{k}} \end{array} \]
(FPCore (k n) :precision binary64 (sqrt (/ 1.0 k)))
double code(double k, double n) {
	return sqrt((1.0 / k));
}
real(8) function code(k, n)
    real(8), intent (in) :: k
    real(8), intent (in) :: n
    code = sqrt((1.0d0 / k))
end function
public static double code(double k, double n) {
	return Math.sqrt((1.0 / k));
}
def code(k, n):
	return math.sqrt((1.0 / k))
function code(k, n)
	return sqrt(Float64(1.0 / k))
end
function tmp = code(k, n)
	tmp = sqrt((1.0 / k));
end
code[k_, n_] := N[Sqrt[N[(1.0 / k), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\frac{1}{k}}
\end{array}
Derivation
  1. Initial program 99.3%

    \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
  2. Add Preprocessing
  3. Taylor expanded in k around inf

    \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\color{blue}{\left(\frac{-1}{2} \cdot k\right)}} \]
  4. Step-by-step derivation
    1. lower-*.f6446.6

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
  5. Simplified46.6%

    \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\color{blue}{\left(-0.5 \cdot k\right)}} \]
  6. Taylor expanded in k around 0

    \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
  7. Step-by-step derivation
    1. lower-sqrt.f64N/A

      \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
    2. lower-/.f645.4

      \[\leadsto \sqrt{\color{blue}{\frac{1}{k}}} \]
  8. Simplified5.4%

    \[\leadsto \color{blue}{\sqrt{\frac{1}{k}}} \]
  9. Add Preprocessing

Reproduce

?
herbie shell --seed 2024210 
(FPCore (k n)
  :name "Migdal et al, Equation (51)"
  :precision binary64
  (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 PI) n) (/ (- 1.0 k) 2.0))))