2-ancestry mixing, negative discriminant

Percentage Accurate: 98.5% → 100.0%
Time: 3.7s
Alternatives: 3
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ 2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \end{array} \]
(FPCore (g h)
 :precision binary64
 (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
\begin{array}{l}

\\
2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\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 3 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: 98.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \end{array} \]
(FPCore (g h)
 :precision binary64
 (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
\begin{array}{l}

\\
2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}

Alternative 1: 100.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \sin \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), -0.16666666666666666, \cos^{-1} \left(\frac{-g}{h}\right) \cdot -0.3333333333333333\right)\right) \cdot 2 \end{array} \]
(FPCore (g h)
 :precision binary64
 (*
  (sin
   (fma (PI) -0.16666666666666666 (* (acos (/ (- g) h)) -0.3333333333333333)))
  2.0))
\begin{array}{l}

\\
\sin \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), -0.16666666666666666, \cos^{-1} \left(\frac{-g}{h}\right) \cdot -0.3333333333333333\right)\right) \cdot 2
\end{array}
Derivation
  1. Initial program 98.5%

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

      \[\leadsto \color{blue}{2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)} \]
    2. *-commutativeN/A

      \[\leadsto \color{blue}{\cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \cdot 2} \]
    3. lower-*.f6498.5

      \[\leadsto \color{blue}{\cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \cdot 2} \]
  4. Applied rewrites98.5%

    \[\leadsto \color{blue}{\cos \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right), 2, \cos^{-1} \left(\frac{-g}{h}\right)\right)}{3}\right) \cdot 2} \]
  5. Applied rewrites99.9%

    \[\leadsto \color{blue}{\sin \left(\mathsf{fma}\left(-0.3333333333333333, \mathsf{fma}\left(\mathsf{PI}\left(\right), 2, \cos^{-1} \left(\frac{-g}{h}\right)\right), \frac{\mathsf{PI}\left(\right)}{2}\right)\right)} \cdot 2 \]
  6. Taylor expanded in g around 0

    \[\leadsto \sin \color{blue}{\left(\frac{-1}{3} \cdot \left(\cos^{-1} \left(-1 \cdot \frac{g}{h}\right) + 2 \cdot \mathsf{PI}\left(\right)\right) + \frac{1}{2} \cdot \mathsf{PI}\left(\right)\right)} \cdot 2 \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \color{blue}{\frac{-1}{3} \cdot \left(\cos^{-1} \left(-1 \cdot \frac{g}{h}\right) + 2 \cdot \mathsf{PI}\left(\right)\right)}\right) \cdot 2 \]
    2. distribute-lft-inN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\frac{-1}{3} \cdot \cos^{-1} \left(-1 \cdot \frac{g}{h}\right) + \color{blue}{\frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)}\right)\right) \cdot 2 \]
    3. metadata-evalN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(-1 \cdot \frac{g}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    4. mul-1-negN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\mathsf{neg}\left(\frac{g}{h}\right)\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    5. distribute-frac-negN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    6. lower-acos.f64N/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    7. lift-/.f64N/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    8. lift-neg.f64N/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{-g}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    9. lift-PI.f64N/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{-g}{h}\right) + \frac{-1}{3} \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot 2 \]
    10. *-commutativeN/A

      \[\leadsto \sin \left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{-g}{h}\right) + \frac{-1}{3} \cdot \left(\mathsf{PI}\left(\right) \cdot \color{blue}{2}\right)\right)\right) \cdot 2 \]
    11. associate-+r+N/A

      \[\leadsto \sin \left(\left(\frac{1}{2} \cdot \mathsf{PI}\left(\right) + \left(\mathsf{neg}\left(\frac{1}{3}\right)\right) \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right) + \color{blue}{\frac{-1}{3} \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)}\right) \cdot 2 \]
  8. Applied rewrites100.0%

    \[\leadsto \sin \color{blue}{\left(\mathsf{fma}\left(\mathsf{PI}\left(\right), -0.16666666666666666, \cos^{-1} \left(\frac{-g}{h}\right) \cdot -0.3333333333333333\right)\right)} \cdot 2 \]
  9. Add Preprocessing

Alternative 2: 98.5% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \cos \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right) \cdot 2 \end{array} \]
(FPCore (g h)
 :precision binary64
 (*
  (cos (fma (PI) 0.6666666666666666 (* 0.3333333333333333 (acos (/ (- g) h)))))
  2.0))
\begin{array}{l}

\\
\cos \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right) \cdot 2
\end{array}
Derivation
  1. Initial program 98.5%

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

      \[\leadsto \color{blue}{2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)} \]
    2. *-commutativeN/A

      \[\leadsto \color{blue}{\cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \cdot 2} \]
    3. lower-*.f6498.5

      \[\leadsto \color{blue}{\cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \cdot 2} \]
  4. Applied rewrites98.5%

    \[\leadsto \color{blue}{\cos \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right), 2, \cos^{-1} \left(\frac{-g}{h}\right)\right)}{3}\right) \cdot 2} \]
  5. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \cos \color{blue}{\left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right), 2, \cos^{-1} \left(\frac{-g}{h}\right)\right)}{3}\right)} \cdot 2 \]
    2. lift-PI.f64N/A

      \[\leadsto \cos \left(\frac{\mathsf{fma}\left(\color{blue}{\mathsf{PI}\left(\right)}, 2, \cos^{-1} \left(\frac{-g}{h}\right)\right)}{3}\right) \cdot 2 \]
    3. lift-fma.f64N/A

      \[\leadsto \cos \left(\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot 2 + \cos^{-1} \left(\frac{-g}{h}\right)}}{3}\right) \cdot 2 \]
    4. *-commutativeN/A

      \[\leadsto \cos \left(\frac{\color{blue}{2 \cdot \mathsf{PI}\left(\right)} + \cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \cdot 2 \]
    5. div-add-revN/A

      \[\leadsto \cos \color{blue}{\left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)} \cdot 2 \]
    6. frac-addN/A

      \[\leadsto \cos \color{blue}{\left(\frac{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot 3 + 3 \cdot \cos^{-1} \left(\frac{-g}{h}\right)}{3 \cdot 3}\right)} \cdot 2 \]
    7. *-commutativeN/A

      \[\leadsto \cos \left(\frac{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot 3 + \color{blue}{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}}{3 \cdot 3}\right) \cdot 2 \]
    8. metadata-evalN/A

      \[\leadsto \cos \left(\frac{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot 3 + \cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{\color{blue}{9}}\right) \cdot 2 \]
    9. div-addN/A

      \[\leadsto \cos \color{blue}{\left(\frac{\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot 3}{9} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right)} \cdot 2 \]
    10. *-commutativeN/A

      \[\leadsto \cos \left(\frac{\color{blue}{\left(\mathsf{PI}\left(\right) \cdot 2\right)} \cdot 3}{9} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right) \cdot 2 \]
    11. associate-*r*N/A

      \[\leadsto \cos \left(\frac{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(2 \cdot 3\right)}}{9} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right) \cdot 2 \]
    12. metadata-evalN/A

      \[\leadsto \cos \left(\frac{\mathsf{PI}\left(\right) \cdot \color{blue}{6}}{9} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right) \cdot 2 \]
    13. associate-/l*N/A

      \[\leadsto \cos \left(\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{6}{9}} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right) \cdot 2 \]
    14. metadata-evalN/A

      \[\leadsto \cos \left(\mathsf{PI}\left(\right) \cdot \color{blue}{\frac{2}{3}} + \frac{\cos^{-1} \left(\frac{-g}{h}\right) \cdot 3}{9}\right) \cdot 2 \]
    15. associate-/l*N/A

      \[\leadsto \cos \left(\mathsf{PI}\left(\right) \cdot \frac{2}{3} + \color{blue}{\cos^{-1} \left(\frac{-g}{h}\right) \cdot \frac{3}{9}}\right) \cdot 2 \]
  6. Applied rewrites98.5%

    \[\leadsto \cos \color{blue}{\left(\mathsf{fma}\left(\mathsf{PI}\left(\right), 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right)} \cdot 2 \]
  7. Add Preprocessing

Alternative 3: 98.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ 2 \cdot \cos \left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right) \end{array} \]
(FPCore (g h)
 :precision binary64
 (*
  2.0
  (cos
   (fma 0.3333333333333333 (acos (/ (- g) h)) (* 0.6666666666666666 (PI))))))
\begin{array}{l}

\\
2 \cdot \cos \left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right)
\end{array}
Derivation
  1. Initial program 98.5%

    \[2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in g around 0

    \[\leadsto 2 \cdot \cos \color{blue}{\left(\frac{1}{3} \cdot \cos^{-1} \left(-1 \cdot \frac{g}{h}\right) + \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)} \]
  4. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto 2 \cdot \cos \left(\frac{1}{3} \cdot \cos^{-1} \left(\mathsf{neg}\left(\frac{g}{h}\right)\right) + \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right) \]
    2. distribute-frac-negN/A

      \[\leadsto 2 \cdot \cos \left(\frac{1}{3} \cdot \cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right) + \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right) \]
    3. lower-fma.f64N/A

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(\frac{1}{3}, \color{blue}{\cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right)}, \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)\right) \]
    4. lift-/.f64N/A

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(\frac{1}{3}, \cos^{-1} \left(\frac{\mathsf{neg}\left(g\right)}{h}\right), \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)\right) \]
    5. lift-neg.f64N/A

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(\frac{1}{3}, \cos^{-1} \left(\frac{-g}{h}\right), \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)\right) \]
    6. lift-acos.f64N/A

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(\frac{1}{3}, \cos^{-1} \left(\frac{-g}{h}\right), \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)\right) \]
    7. lower-*.f64N/A

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(\frac{1}{3}, \cos^{-1} \left(\frac{-g}{h}\right), \frac{2}{3} \cdot \mathsf{PI}\left(\right)\right)\right) \]
    8. lift-PI.f6498.5

      \[\leadsto 2 \cdot \cos \left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right) \]
  5. Applied rewrites98.5%

    \[\leadsto 2 \cdot \cos \color{blue}{\left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right)} \]
  6. Add Preprocessing

Reproduce

?
herbie shell --seed 2025032 
(FPCore (g h)
  :name "2-ancestry mixing, negative discriminant"
  :precision binary64
  (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))