Diagrams.Solve.Polynomial:cubForm from diagrams-solve-0.1, K

Average Error: 20.4 → 17.7

Time: 12.5s

Precision: 64

Math

\[\left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z \cdot t}{3}\right) - \frac{a}{b \cdot 3}\]

↓

\[\begin{array}{l} \mathbf{if}\;z \cdot t = -\infty \lor \neg \left(z \cdot t \le 3.06412081998630938 \cdot 10^{302}\right):\\ \;\;\;\;\left(2 \cdot \sqrt{x}\right) \cdot \left(1 - \frac{1}{2} \cdot {y}^{2}\right) - \frac{a}{b \cdot 3}\\ \mathbf{else}:\\ \;\;\;\;\left(2 \cdot \sqrt{x}\right) \cdot \left(\cos y \cdot \cos \left(\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right) - \sin y \cdot \sin \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)\right) - \frac{a}{b \cdot 3}\\ \end{array}\]

C

double code(double x, double y, double z, double t, double a, double b) {
	return (((2.0 * sqrt(x)) * cos((y - ((z * t) / 3.0)))) - (a / (b * 3.0)));
}

↓

double code(double x, double y, double z, double t, double a, double b) {
	double temp;
	if ((((z * t) <= -inf.0) || !((z * t) <= 3.0641208199863094e+302))) {
		temp = (((2.0 * sqrt(x)) * (1.0 - (0.5 * pow(y, 2.0)))) - (a / (b * 3.0)));
	} else {
		temp = (((2.0 * sqrt(x)) * ((cos(y) * cos(((z / (cbrt(3.0) * cbrt(3.0))) * (t * ((cbrt((1.0 / cbrt(3.0))) * cbrt((1.0 / cbrt(3.0)))) * cbrt((1.0 / cbrt(3.0)))))))) - (sin(y) * sin(-((z / (cbrt(3.0) * cbrt(3.0))) * (t * ((cbrt((1.0 / cbrt(3.0))) * cbrt((1.0 / cbrt(3.0)))) * cbrt((1.0 / cbrt(3.0)))))))))) - (a / (b * 3.0)));
	}
	return temp;
}

Error

Bits error versus x

Bits error versus y

Bits error versus z

Bits error versus t

Bits error versus a

Bits error versus b

Target

Original	20.4
Target	18.4
Herbie	17.7

\[\begin{array}{l} \mathbf{if}\;z \lt -1.379333748723514 \cdot 10^{129}:\\ \;\;\;\;\left(2 \cdot \sqrt{x}\right) \cdot \cos \left(\frac{1}{y} - \frac{\frac{0.333333333333333315}{z}}{t}\right) - \frac{\frac{a}{3}}{b}\\ \mathbf{elif}\;z \lt 3.51629061355598715 \cdot 10^{106}:\\ \;\;\;\;\left(\sqrt{x} \cdot 2\right) \cdot \cos \left(y - \frac{t}{3} \cdot z\right) - \frac{\frac{a}{3}}{b}\\ \mathbf{else}:\\ \;\;\;\;\cos \left(y - \frac{\frac{0.333333333333333315}{z}}{t}\right) \cdot \left(2 \cdot \sqrt{x}\right) - \frac{\frac{a}{b}}{3}\\ \end{array}\]

Derivation

1. Split input into 2 regimes

2. if (* z t) < -inf.0 or 3.0641208199863094e+302 < (* z t)

   1. Initial program 63.3

      \[\left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z \cdot t}{3}\right) - \frac{a}{b \cdot 3}\]

   2. Taylor expanded around 0 45.0

      \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \color{blue}{\left(1 - \frac{1}{2} \cdot {y}^{2}\right)} - \frac{a}{b \cdot 3}\]

   if -inf.0 < (* z t) < 3.0641208199863094e+302

   1. Initial program 14.1

      \[\left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z \cdot t}{3}\right) - \frac{a}{b \cdot 3}\]
   2. Using strategy rm

   3. Applied add-cube-cbrt 14.1

      \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z \cdot t}{\color{blue}{\left(\sqrt[3]{3} \cdot \sqrt[3]{3}\right) \cdot \sqrt[3]{3}}}\right) - \frac{a}{b \cdot 3}\]

   4. Applied times-frac 14.1

      \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \color{blue}{\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \frac{t}{\sqrt[3]{3}}}\right) - \frac{a}{b \cdot 3}\]
   5. Using strategy rm

   6. Applied div-inv 14.1

      \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \color{blue}{\left(t \cdot \frac{1}{\sqrt[3]{3}}\right)}\right) - \frac{a}{b \cdot 3}\]
   7. Using strategy rm

   8. Applied add-cube-cbrt 14.1

      \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \cos \left(y - \frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \color{blue}{\left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)}\right)\right) - \frac{a}{b \cdot 3}\]
   9. Using strategy rm

   10. Applied sub-neg 14.1

       \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \cos \color{blue}{\left(y + \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)\right)} - \frac{a}{b \cdot 3}\]

   11. Applied cos-sum 13.7

       \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \color{blue}{\left(\cos y \cdot \cos \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right) - \sin y \cdot \sin \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)\right)} - \frac{a}{b \cdot 3}\]

   12. Simplified 13.7

       \[\leadsto \left(2 \cdot \sqrt{x}\right) \cdot \left(\color{blue}{\cos y \cdot \cos \left(\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)} - \sin y \cdot \sin \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)\right) - \frac{a}{b \cdot 3}\]
3. Recombined 2 regimes into one program.

4. Final simplification 17.7

   \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot t = -\infty \lor \neg \left(z \cdot t \le 3.06412081998630938 \cdot 10^{302}\right):\\ \;\;\;\;\left(2 \cdot \sqrt{x}\right) \cdot \left(1 - \frac{1}{2} \cdot {y}^{2}\right) - \frac{a}{b \cdot 3}\\ \mathbf{else}:\\ \;\;\;\;\left(2 \cdot \sqrt{x}\right) \cdot \left(\cos y \cdot \cos \left(\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right) - \sin y \cdot \sin \left(-\frac{z}{\sqrt[3]{3} \cdot \sqrt[3]{3}} \cdot \left(t \cdot \left(\left(\sqrt[3]{\frac{1}{\sqrt[3]{3}}} \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right) \cdot \sqrt[3]{\frac{1}{\sqrt[3]{3}}}\right)\right)\right)\right) - \frac{a}{b \cdot 3}\\ \end{array}\]

Reproduce

herbie shell --seed 2020066 +o rules:numerics
(FPCore (x y z t a b)
  :name "Diagrams.Solve.Polynomial:cubForm  from diagrams-solve-0.1, K"
  :precision binary64

  :herbie-target
  (if (< z -1.379333748723514e+129) (- (* (* 2 (sqrt x)) (cos (- (/ 1 y) (/ (/ 0.3333333333333333 z) t)))) (/ (/ a 3) b)) (if (< z 3.516290613555987e+106) (- (* (* (sqrt x) 2) (cos (- y (* (/ t 3) z)))) (/ (/ a 3) b)) (- (* (cos (- y (/ (/ 0.3333333333333333 z) t))) (* 2 (sqrt x))) (/ (/ a b) 3))))

  (- (* (* 2 (sqrt x)) (cos (- y (/ (* z t) 3)))) (/ a (* b 3))))