Migdal et al, Equation (51)

Percentage Accurate: 99.4% → 99.5%
Time: 7.4s
Alternatives: 10
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 (PI)) n) (/ (- 1.0 k) 2.0))))
\begin{array}{l}

\\
\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\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?

\[\begin{array}{l} \\ \frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 (PI)) n) (/ (- 1.0 k) 2.0))))
\begin{array}{l}

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

Alternative 1: 99.5% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \frac{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n}}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(0.5 \cdot k\right)} \cdot \sqrt{k}} \end{array} \]
(FPCore (k n)
 :precision binary64
 (/ (sqrt (* (* 2.0 (PI)) n)) (* (pow (* (* 2.0 n) (PI)) (* 0.5 k)) (sqrt k))))
\begin{array}{l}

\\
\frac{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n}}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(0.5 \cdot k\right)} \cdot \sqrt{k}}
\end{array}
Derivation
  1. Initial program 99.5%

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

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \color{blue}{\frac{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}}{\sqrt{k} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{k}{2}\right)}}} \]
  4. Applied rewrites99.7%

    \[\leadsto \color{blue}{\frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left({\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{k}\right)}^{0.5}}} \]
  5. Step-by-step derivation
    1. lift-pow.f64N/A

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

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

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left(\color{blue}{\left(2 \cdot n\right)} \cdot \mathsf{PI}\left(\right)\right)}^{\left(\frac{1}{2} \cdot k\right)}} \]
    15. lower-*.f6499.7

      \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\color{blue}{\left(0.5 \cdot k\right)}}} \]
  6. Applied rewrites99.7%

    \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot \color{blue}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(0.5 \cdot k\right)}}} \]
  7. Final simplification99.7%

    \[\leadsto \frac{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n}}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(0.5 \cdot k\right)} \cdot \sqrt{k}} \]
  8. Add Preprocessing

Alternative 2: 99.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\\ \frac{\sqrt{t\_0}}{\sqrt{{t\_0}^{k} \cdot k}} \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (let* ((t_0 (* (* 2.0 n) (PI)))) (/ (sqrt t_0) (sqrt (* (pow t_0 k) k)))))
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\\
\frac{\sqrt{t\_0}}{\sqrt{{t\_0}^{k} \cdot k}}
\end{array}
\end{array}
Derivation
  1. Initial program 99.5%

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

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

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

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

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

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

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

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)\right)\right)}} \]
    8. neg-sub0N/A

      \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\color{blue}{\left(0 - \left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)\right)}} \]
    9. pow-subN/A

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\frac{{\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{0}}{{\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)}}} \]
    10. metadata-evalN/A

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}}\right)}^{\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)}} \]
    21. neg-sub0N/A

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\color{blue}{\left(0 - \left(1 - k\right)\right)}}} \]
    22. lift--.f64N/A

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(0 - \color{blue}{\left(1 - k\right)}\right)}} \]
    23. sub-negN/A

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(0 - \color{blue}{\left(1 + \left(\mathsf{neg}\left(k\right)\right)\right)}\right)}} \]
  4. Applied rewrites99.5%

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \frac{1}{\sqrt{k} \cdot \left({\color{blue}{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}}^{k} \cdot {\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{-1}\right)} \]
    12. sqrt-pow2N/A

      \[\leadsto \frac{1}{\sqrt{k} \cdot \left(\color{blue}{{\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{\left(\frac{k}{2}\right)}} \cdot {\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{-1}\right)} \]
    13. sqrt-pow1N/A

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

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

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

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

      \[\leadsto \frac{1}{\sqrt{k} \cdot \left({\left({\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{k}\right)}^{\frac{1}{2}} \cdot \color{blue}{\frac{1}{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}}\right)} \]
  6. Applied rewrites99.6%

    \[\leadsto \color{blue}{\frac{\sqrt{\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)}}{\sqrt{k \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{k}}}} \]
  7. Final simplification99.6%

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

Alternative 3: 99.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{1}{k}} \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)} \end{array} \]
(FPCore (k n)
 :precision binary64
 (* (sqrt (/ 1.0 k)) (pow (* (* 2.0 n) (PI)) (fma -0.5 k 0.5))))
\begin{array}{l}

\\
\sqrt{\frac{1}{k}} \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)}
\end{array}
Derivation
  1. Initial program 99.5%

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

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

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

      \[\leadsto \color{blue}{e^{\frac{1}{2} \cdot \left(\log \left(2 \cdot \left(n \cdot \mathsf{PI}\left(\right)\right)\right) \cdot \left(1 - k\right)\right)} \cdot \sqrt{\frac{1}{k}}} \]
  5. Applied rewrites99.6%

    \[\leadsto \color{blue}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)} \cdot \sqrt{\frac{1}{k}}} \]
  6. Final simplification99.6%

    \[\leadsto \sqrt{\frac{1}{k}} \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)} \]
  7. Add Preprocessing

Alternative 4: 99.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;k \leq 1.06 \cdot 10^{-20}:\\ \;\;\;\;\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{0.5 \cdot k}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(1 - k\right)}}{k}}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= k 1.06e-20)
   (/ (sqrt (* (PI) n)) (sqrt (* 0.5 k)))
   (sqrt (/ (pow (* (* 2.0 n) (PI)) (- 1.0 k)) k))))
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;k \leq 1.06 \cdot 10^{-20}:\\
\;\;\;\;\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{0.5 \cdot k}}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if k < 1.06e-20

    1. Initial program 99.3%

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

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

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

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

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

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

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

        \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
      8. lower-PI.f6471.7

        \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
    5. Applied rewrites71.7%

      \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
    6. Step-by-step derivation
      1. Applied rewrites71.8%

        \[\leadsto \color{blue}{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{n}{k}}} \]
      2. Step-by-step derivation
        1. Applied rewrites72.3%

          \[\leadsto \sqrt{\frac{n}{k} \cdot 2} \cdot \color{blue}{\sqrt{\mathsf{PI}\left(\right)}} \]
        2. Step-by-step derivation
          1. Applied rewrites99.5%

            \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{0.5 \cdot k}}} \]

          if 1.06e-20 < k

          1. Initial program 99.7%

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

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

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

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

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

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

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

              \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)\right)\right)}} \]
            8. neg-sub0N/A

              \[\leadsto \frac{1}{\sqrt{k}} \cdot {\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\color{blue}{\left(0 - \left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)\right)}} \]
            9. pow-subN/A

              \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\frac{{\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{0}}{{\left({\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}\right)}^{\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)}}} \]
            10. metadata-evalN/A

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

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

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

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

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

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

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

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

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

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

              \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}}\right)}^{\left(\mathsf{neg}\left(\left(1 - k\right)\right)\right)}} \]
            21. neg-sub0N/A

              \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\color{blue}{\left(0 - \left(1 - k\right)\right)}}} \]
            22. lift--.f64N/A

              \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(0 - \color{blue}{\left(1 - k\right)}\right)}} \]
            23. sub-negN/A

              \[\leadsto \frac{1}{\sqrt{k}} \cdot \frac{1}{{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(0 - \color{blue}{\left(1 + \left(\mathsf{neg}\left(k\right)\right)\right)}\right)}} \]
          4. Applied rewrites99.7%

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

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

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

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

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

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

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

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

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

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

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

              \[\leadsto \frac{1}{\sqrt{k} \cdot \left({\color{blue}{\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}}^{k} \cdot {\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{-1}\right)} \]
            12. sqrt-pow2N/A

              \[\leadsto \frac{1}{\sqrt{k} \cdot \left(\color{blue}{{\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{\left(\frac{k}{2}\right)}} \cdot {\left(\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{-1}\right)} \]
            13. sqrt-pow1N/A

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

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

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

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

              \[\leadsto \frac{1}{\sqrt{k} \cdot \left({\left({\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{k}\right)}^{\frac{1}{2}} \cdot \color{blue}{\frac{1}{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}}\right)} \]
          6. Applied rewrites100.0%

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

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

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

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

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

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

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

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

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

              \[\leadsto \sqrt{\color{blue}{\frac{\frac{\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{k}}}{k}}} \]
          8. Applied rewrites99.7%

            \[\leadsto \color{blue}{\sqrt{\frac{{\left(\mathsf{PI}\left(\right) \cdot \left(n \cdot 2\right)\right)}^{\left(1 - k\right)}}{k}}} \]
        3. Recombined 2 regimes into one program.
        4. Final simplification99.6%

          \[\leadsto \begin{array}{l} \mathbf{if}\;k \leq 1.06 \cdot 10^{-20}:\\ \;\;\;\;\frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{0.5 \cdot k}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(1 - k\right)}}{k}}\\ \end{array} \]
        5. Add Preprocessing

        Alternative 5: 99.4% accurate, 1.1× speedup?

        \[\begin{array}{l} \\ \frac{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)}}{\sqrt{k}} \end{array} \]
        (FPCore (k n)
         :precision binary64
         (/ (pow (* (* 2.0 n) (PI)) (fma -0.5 k 0.5)) (sqrt k)))
        \begin{array}{l}
        
        \\
        \frac{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)}}{\sqrt{k}}
        \end{array}
        
        Derivation
        1. Initial program 99.5%

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

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

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

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

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

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

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

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

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

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

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

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

            \[\leadsto \color{blue}{\frac{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\frac{1}{2}}}{\sqrt{k} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{k}{2}\right)}}} \]
        4. Applied rewrites99.7%

          \[\leadsto \color{blue}{\frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left({\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{k}\right)}^{0.5}}} \]
        5. Step-by-step derivation
          1. lift-pow.f64N/A

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

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

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

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

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

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

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

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

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

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

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

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

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

            \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left(\color{blue}{\left(2 \cdot n\right)} \cdot \mathsf{PI}\left(\right)\right)}^{\left(\frac{1}{2} \cdot k\right)}} \]
          15. lower-*.f6499.7

            \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\color{blue}{\left(0.5 \cdot k\right)}}} \]
        6. Applied rewrites99.7%

          \[\leadsto \frac{\sqrt{n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}}{\sqrt{k} \cdot \color{blue}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(0.5 \cdot k\right)}}} \]
        7. Applied rewrites99.5%

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

        Alternative 6: 48.5% accurate, 3.6× speedup?

        \[\begin{array}{l} \\ \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{0.5 \cdot k}} \end{array} \]
        (FPCore (k n) :precision binary64 (/ (sqrt (* (PI) n)) (sqrt (* 0.5 k))))
        \begin{array}{l}
        
        \\
        \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\sqrt{0.5 \cdot k}}
        \end{array}
        
        Derivation
        1. Initial program 99.5%

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

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

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

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

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

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

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

            \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
          8. lower-PI.f6437.8

            \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
        5. Applied rewrites37.8%

          \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
        6. Step-by-step derivation
          1. Applied rewrites37.9%

            \[\leadsto \color{blue}{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{n}{k}}} \]
          2. Step-by-step derivation
            1. Applied rewrites38.1%

              \[\leadsto \sqrt{\frac{n}{k} \cdot 2} \cdot \color{blue}{\sqrt{\mathsf{PI}\left(\right)}} \]
            2. Step-by-step derivation
              1. Applied rewrites51.4%

                \[\leadsto \frac{\sqrt{\mathsf{PI}\left(\right) \cdot n}}{\color{blue}{\sqrt{0.5 \cdot k}}} \]
              2. Add Preprocessing

              Alternative 7: 48.5% accurate, 3.6× speedup?

              \[\begin{array}{l} \\ \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}} \cdot \sqrt{n} \end{array} \]
              (FPCore (k n) :precision binary64 (* (sqrt (/ (* 2.0 (PI)) k)) (sqrt n)))
              \begin{array}{l}
              
              \\
              \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}} \cdot \sqrt{n}
              \end{array}
              
              Derivation
              1. Initial program 99.5%

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

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

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

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

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

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

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

                  \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
                8. lower-PI.f6437.8

                  \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
              5. Applied rewrites37.8%

                \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
              6. Step-by-step derivation
                1. Applied rewrites51.4%

                  \[\leadsto \sqrt{n} \cdot \color{blue}{\sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}}} \]
                2. Final simplification51.4%

                  \[\leadsto \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}} \cdot \sqrt{n} \]
                3. Add Preprocessing

                Alternative 8: 37.9% accurate, 4.0× speedup?

                \[\begin{array}{l} \\ \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{\frac{k}{n}}} \end{array} \]
                (FPCore (k n) :precision binary64 (sqrt (/ (* 2.0 (PI)) (/ k n))))
                \begin{array}{l}
                
                \\
                \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{\frac{k}{n}}}
                \end{array}
                
                Derivation
                1. Initial program 99.5%

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

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

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

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

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

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

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

                    \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
                  8. lower-PI.f6437.8

                    \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
                5. Applied rewrites37.8%

                  \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
                6. Step-by-step derivation
                  1. Applied rewrites37.9%

                    \[\leadsto \color{blue}{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{n}{k}}} \]
                  2. Step-by-step derivation
                    1. Applied rewrites37.9%

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

                    Alternative 9: 37.9% accurate, 4.8× speedup?

                    \[\begin{array}{l} \\ \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k} \cdot n} \end{array} \]
                    (FPCore (k n) :precision binary64 (sqrt (* (/ (* 2.0 (PI)) k) n)))
                    \begin{array}{l}
                    
                    \\
                    \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k} \cdot n}
                    \end{array}
                    
                    Derivation
                    1. Initial program 99.5%

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

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

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

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

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

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

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

                        \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
                      8. lower-PI.f6437.8

                        \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
                    5. Applied rewrites37.8%

                      \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
                    6. Step-by-step derivation
                      1. Applied rewrites37.9%

                        \[\leadsto \color{blue}{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{n}{k}}} \]
                      2. Step-by-step derivation
                        1. Applied rewrites37.9%

                          \[\leadsto \color{blue}{\sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k} \cdot n}} \]
                        2. Add Preprocessing

                        Alternative 10: 37.9% accurate, 4.8× speedup?

                        \[\begin{array}{l} \\ \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k} \cdot 2} \end{array} \]
                        (FPCore (k n) :precision binary64 (sqrt (* (/ (* (PI) n) k) 2.0)))
                        \begin{array}{l}
                        
                        \\
                        \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k} \cdot 2}
                        \end{array}
                        
                        Derivation
                        1. Initial program 99.5%

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

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

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

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

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

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

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

                            \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot n}}{k}} \]
                          8. lower-PI.f6437.8

                            \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
                        5. Applied rewrites37.8%

                          \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
                        6. Step-by-step derivation
                          1. Applied rewrites37.9%

                            \[\leadsto \color{blue}{\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{n}{k}}} \]
                          2. Taylor expanded in k around 0

                            \[\leadsto \sqrt{2 \cdot \frac{n \cdot \mathsf{PI}\left(\right)}{k}} \]
                          3. Step-by-step derivation
                            1. Applied rewrites37.9%

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

                            Reproduce

                            ?
                            herbie shell --seed 2024308 
                            (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))))