System.Random.MWC.Distributions:gamma from mwc-random-0.13.3.2

Average Error: 0.1 → 0.1

Time: 7.4s

Precision: 64

Math

\[x \cdot 0.5 + y \cdot \left(\left(1 - z\right) + \log z\right)\]

↓

\[x \cdot 0.5 + y \cdot \left(\left(1 - z\right) + \log z\right)\]

C

double f(double x, double y, double z) {
        double r198486 = x;
        double r198487 = 0.5;
        double r198488 = r198486 * r198487;
        double r198489 = y;
        double r198490 = 1.0;
        double r198491 = z;
        double r198492 = r198490 - r198491;
        double r198493 = log(r198491);
        double r198494 = r198492 + r198493;
        double r198495 = r198489 * r198494;
        double r198496 = r198488 + r198495;
        return r198496;
}

↓

double f(double x, double y, double z) {
        double r198497 = x;
        double r198498 = 0.5;
        double r198499 = r198497 * r198498;
        double r198500 = y;
        double r198501 = 1.0;
        double r198502 = z;
        double r198503 = r198501 - r198502;
        double r198504 = log(r198502);
        double r198505 = r198503 + r198504;
        double r198506 = r198500 * r198505;
        double r198507 = r198499 + r198506;
        return r198507;
}

Error

Bits error versus x

Bits error versus y

Bits error versus z

Target

Original	0.1
Target	0.1
Herbie	0.1

\[\left(y + 0.5 \cdot x\right) - y \cdot \left(z - \log z\right)\]

Derivation

1. Initial program 0.1

   \[x \cdot 0.5 + y \cdot \left(\left(1 - z\right) + \log z\right)\]

2. Final simplification 0.1

   \[\leadsto x \cdot 0.5 + y \cdot \left(\left(1 - z\right) + \log z\right)\]

Reproduce

herbie shell --seed 2019308 
(FPCore (x y z)
  :name "System.Random.MWC.Distributions:gamma from mwc-random-0.13.3.2"
  :precision binary64

  :herbie-target
  (- (+ y (* 0.5 x)) (* y (- z (log z))))

  (+ (* x 0.5) (* y (+ (- 1 z) (log z)))))