Migdal et al, Equation (51)

Percentage Accurate: 99.5% → 99.6%
Time: 9.7s
Alternatives: 11
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 11 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: 99.5% 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: 99.6% accurate, 1.0× speedup?

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

\\
\begin{array}{l}
t_0 := 2 \cdot \mathsf{PI}\left(\right)\\
\sqrt{n} \cdot \sqrt{\frac{t\_0}{k \cdot {\left(t\_0 \cdot n\right)}^{k}}}
\end{array}
\end{array}
Derivation
  1. Initial program 99.4%

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

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

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

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

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

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\sqrt{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}} \]
    8. lower-pow.f6499.4

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

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

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\color{blue}{\left(n \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)}}^{\left(1 - k\right)}} \]
    11. lower-*.f6499.4

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

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

      \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\left(n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(1 - k\right)}} \]
    14. lower-*.f6499.4

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Alternative 2: 99.4% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;k \leq 3.2 \cdot 10^{-30}:\\ \;\;\;\;\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot {k}^{-0.5}\\ \mathbf{else}:\\ \;\;\;\;{\left(\sqrt{k \cdot {\left(\left(n \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(k - 1\right)}}\right)}^{-1}\\ \end{array} \end{array} \]
(FPCore (k n)
 :precision binary64
 (if (<= k 3.2e-30)
   (* (sqrt (* (* 2.0 (PI)) n)) (pow k -0.5))
   (pow (sqrt (* k (pow (* (* n 2.0) (PI)) (- k 1.0)))) -1.0)))
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;k \leq 3.2 \cdot 10^{-30}:\\
\;\;\;\;\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot {k}^{-0.5}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if k < 3.2e-30

    1. Initial program 99.4%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    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.f6472.3

        \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
    5. Applied rewrites72.3%

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

        \[\leadsto \sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot \color{blue}{{k}^{-0.5}} \]

      if 3.2e-30 < k

      1. Initial program 99.4%

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

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

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

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\sqrt{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}} \]
        8. lower-pow.f6499.4

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\color{blue}{\left(n \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)}}^{\left(1 - k\right)}} \]
        11. lower-*.f6499.4

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\left(n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(1 - k\right)}} \]
        14. lower-*.f6499.4

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

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

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

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

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

          \[\leadsto \frac{\color{blue}{\sqrt{{\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{\left(1 - k\right)}}}}{\sqrt{k}} \]
        5. lower-/.f6499.4

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

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

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

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

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

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

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

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

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

          \[\leadsto \frac{\color{blue}{\sqrt{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}}}{\sqrt{k}} \]
        9. lower-pow.f6499.4

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

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

          \[\leadsto \frac{\sqrt{{\left(\color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)} \cdot n\right)}^{\left(1 - k\right)}}}{\sqrt{k}} \]
        12. lower-*.f6499.4

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

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

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

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

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

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

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

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

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

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

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

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

          \[\leadsto \frac{1}{\sqrt{k \cdot \frac{1}{\color{blue}{\frac{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{1}}{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{k}}}}}} \]
        12. unpow1N/A

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

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

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

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

          \[\leadsto \frac{1}{\sqrt{k \cdot \frac{1}{\frac{\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n}{{\left(\left(2 \cdot \color{blue}{\mathsf{PI}\left(\right)}\right) \cdot n\right)}^{k}}}}} \]
      10. Applied rewrites99.3%

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

      \[\leadsto \begin{array}{l} \mathbf{if}\;k \leq 3.2 \cdot 10^{-30}:\\ \;\;\;\;\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot {k}^{-0.5}\\ \mathbf{else}:\\ \;\;\;\;{\left(\sqrt{k \cdot {\left(\left(n \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(k - 1\right)}}\right)}^{-1}\\ \end{array} \]
    9. Add Preprocessing

    Alternative 3: 99.5% accurate, 0.6× speedup?

    \[\begin{array}{l} \\ {\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)} \cdot \sqrt{{k}^{-1}} \end{array} \]
    (FPCore (k n)
     :precision binary64
     (* (pow (* (* 2.0 n) (PI)) (fma -0.5 k 0.5)) (sqrt (pow k -1.0))))
    \begin{array}{l}
    
    \\
    {\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{{k}^{-1}}
    \end{array}
    
    Derivation
    1. Initial program 99.4%

      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
    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 rewrites99.4%

      \[\leadsto \color{blue}{{\left(\left(2 \cdot n\right) \cdot \mathsf{PI}\left(\right)\right)}^{\left(\mathsf{fma}\left(-0.5, k, 0.5\right)\right)} \cdot \sqrt{\frac{1}{k}}} \]
    6. Final simplification99.4%

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

    Alternative 4: 99.3% accurate, 1.1× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\\ \mathbf{if}\;k \leq 2.2 \cdot 10^{-31}:\\ \;\;\;\;\sqrt{t\_0} \cdot {k}^{-0.5}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{{t\_0}^{\left(1 - k\right)}}{k}}\\ \end{array} \end{array} \]
    (FPCore (k n)
     :precision binary64
     (let* ((t_0 (* (* 2.0 (PI)) n)))
       (if (<= k 2.2e-31)
         (* (sqrt t_0) (pow k -0.5))
         (sqrt (/ (pow t_0 (- 1.0 k)) k)))))
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\\
    \mathbf{if}\;k \leq 2.2 \cdot 10^{-31}:\\
    \;\;\;\;\sqrt{t\_0} \cdot {k}^{-0.5}\\
    
    \mathbf{else}:\\
    \;\;\;\;\sqrt{\frac{{t\_0}^{\left(1 - k\right)}}{k}}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if k < 2.2000000000000001e-31

      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.f6471.8

          \[\leadsto \sqrt{2} \cdot \sqrt{\frac{\color{blue}{\mathsf{PI}\left(\right)} \cdot n}{k}} \]
      5. Applied rewrites71.8%

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

          \[\leadsto \sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot \color{blue}{{k}^{-0.5}} \]

        if 2.2000000000000001e-31 < k

        1. Initial program 99.4%

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

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

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

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

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

            \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\sqrt{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}} \]
          8. lower-pow.f6499.4

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

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

            \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\color{blue}{\left(n \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)}}^{\left(1 - k\right)}} \]
          11. lower-*.f6499.4

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

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

            \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\left(n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(1 - k\right)}} \]
          14. lower-*.f6499.4

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

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

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

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

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

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

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

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

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

            \[\leadsto \color{blue}{\sqrt{\frac{{\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{\left(1 - k\right)}}{k}}} \]
          9. lower-/.f6498.8

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

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

            \[\leadsto \sqrt{\frac{{\color{blue}{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}}^{\left(1 - k\right)}}{k}} \]
          12. lower-*.f6498.8

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

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

            \[\leadsto \sqrt{\frac{{\left(\color{blue}{\left(2 \cdot \mathsf{PI}\left(\right)\right)} \cdot n\right)}^{\left(1 - k\right)}}{k}} \]
          15. lift-*.f6498.8

            \[\leadsto \sqrt{\frac{{\left(\color{blue}{\left(2 \cdot \mathsf{PI}\left(\right)\right)} \cdot n\right)}^{\left(1 - k\right)}}{k}} \]
        6. Applied rewrites98.8%

          \[\leadsto \color{blue}{\sqrt{\frac{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}{k}}} \]
      7. Recombined 2 regimes into one program.
      8. Add Preprocessing

      Alternative 5: 99.5% accurate, 1.1× speedup?

      \[\begin{array}{l} \\ \frac{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{\left(0.5 - 0.5 \cdot k\right)}}{\sqrt{k}} \end{array} \]
      (FPCore (k n)
       :precision binary64
       (/ (pow (* (* (PI) 2.0) n) (- 0.5 (* 0.5 k))) (sqrt k)))
      \begin{array}{l}
      
      \\
      \frac{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{\left(0.5 - 0.5 \cdot k\right)}}{\sqrt{k}}
      \end{array}
      
      Derivation
      1. Initial program 99.4%

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

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

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

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \color{blue}{\sqrt{{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(1 - k\right)}}} \]
        8. lower-pow.f6499.4

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\color{blue}{\left(n \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)}}^{\left(1 - k\right)}} \]
        11. lower-*.f6499.4

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

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

          \[\leadsto \frac{1}{\sqrt{k}} \cdot \sqrt{{\left(n \cdot \color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)}\right)}^{\left(1 - k\right)}} \]
        14. lower-*.f6499.4

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

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

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

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

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

          \[\leadsto \frac{\color{blue}{\sqrt{{\left(n \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)}^{\left(1 - k\right)}}}}{\sqrt{k}} \]
        5. lower-/.f6499.4

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

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

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

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

          \[\leadsto \frac{\color{blue}{\frac{{\left(\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n}\right)}^{1}}{{\left(\sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n}\right)}^{k}}}}{\sqrt{k}} \]
        4. unpow1N/A

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

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

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

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

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

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

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

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

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

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

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

          \[\leadsto \frac{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{\color{blue}{\left(\frac{1}{2} - \frac{1}{2} \cdot k\right)}}}{\sqrt{k}} \]
        16. lower-*.f6499.4

          \[\leadsto \frac{{\left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot n\right)}^{\left(0.5 - \color{blue}{0.5 \cdot k}\right)}}{\sqrt{k}} \]
      8. Applied rewrites99.4%

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

      Alternative 6: 49.3% accurate, 1.2× speedup?

      \[\begin{array}{l} \\ \sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot {k}^{-0.5} \end{array} \]
      (FPCore (k n) :precision binary64 (* (sqrt (* (* 2.0 (PI)) n)) (pow k -0.5)))
      \begin{array}{l}
      
      \\
      \sqrt{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n} \cdot {k}^{-0.5}
      \end{array}
      
      Derivation
      1. Initial program 99.4%

        \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
      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.f6437.2

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

        \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
      6. Step-by-step derivation
        1. Applied rewrites48.8%

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

        Alternative 7: 49.2% accurate, 3.6× speedup?

        \[\begin{array}{l} \\ \sqrt{n} \cdot \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}} \end{array} \]
        (FPCore (k n) :precision binary64 (* (sqrt n) (sqrt (/ (* 2.0 (PI)) k))))
        \begin{array}{l}
        
        \\
        \sqrt{n} \cdot \sqrt{\frac{2 \cdot \mathsf{PI}\left(\right)}{k}}
        \end{array}
        
        Derivation
        1. Initial program 99.4%

          \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
        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.f6437.2

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

          \[\leadsto \color{blue}{\sqrt{2} \cdot \sqrt{\frac{\mathsf{PI}\left(\right) \cdot n}{k}}} \]
        6. Step-by-step derivation
          1. Applied rewrites48.8%

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

          Alternative 8: 37.7% accurate, 4.0× speedup?

          \[\begin{array}{l} \\ \sqrt{\frac{n}{\frac{k}{\mathsf{PI}\left(\right)}} \cdot 2} \end{array} \]
          (FPCore (k n) :precision binary64 (sqrt (* (/ n (/ k (PI))) 2.0)))
          \begin{array}{l}
          
          \\
          \sqrt{\frac{n}{\frac{k}{\mathsf{PI}\left(\right)}} \cdot 2}
          \end{array}
          
          Derivation
          1. Initial program 99.4%

            \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
          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.f6437.2

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

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

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

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

              Alternative 9: 37.7% 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 99.4%

                \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
              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.f6437.2

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

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

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

                Alternative 10: 37.7% accurate, 4.8× speedup?

                \[\begin{array}{l} \\ \sqrt{\left(\frac{n}{k} \cdot \mathsf{PI}\left(\right)\right) \cdot 2} \end{array} \]
                (FPCore (k n) :precision binary64 (sqrt (* (* (/ n k) (PI)) 2.0)))
                \begin{array}{l}
                
                \\
                \sqrt{\left(\frac{n}{k} \cdot \mathsf{PI}\left(\right)\right) \cdot 2}
                \end{array}
                
                Derivation
                1. Initial program 99.4%

                  \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
                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.f6437.2

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

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

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

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

                    Alternative 11: 37.7% accurate, 4.8× speedup?

                    \[\begin{array}{l} \\ \sqrt{\left(\mathsf{PI}\left(\right) \cdot \frac{2}{k}\right) \cdot n} \end{array} \]
                    (FPCore (k n) :precision binary64 (sqrt (* (* (PI) (/ 2.0 k)) n)))
                    \begin{array}{l}
                    
                    \\
                    \sqrt{\left(\mathsf{PI}\left(\right) \cdot \frac{2}{k}\right) \cdot n}
                    \end{array}
                    
                    Derivation
                    1. Initial program 99.4%

                      \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)} \]
                    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.f6437.2

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

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

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

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

                        Reproduce

                        ?
                        herbie shell --seed 2024296 
                        (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))))