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

Average Error: 0.1 → 0.1

Time: 16.6s

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 r260390 = x;
        double r260391 = 0.5;
        double r260392 = r260390 * r260391;
        double r260393 = y;
        double r260394 = 1.0;
        double r260395 = z;
        double r260396 = r260394 - r260395;
        double r260397 = log(r260395);
        double r260398 = r260396 + r260397;
        double r260399 = r260393 * r260398;
        double r260400 = r260392 + r260399;
        return r260400;
}

↓

double f(double x, double y, double z) {
        double r260401 = x;
        double r260402 = 0.5;
        double r260403 = r260401 * r260402;
        double r260404 = y;
        double r260405 = 1.0;
        double r260406 = z;
        double r260407 = r260405 - r260406;
        double r260408 = log(r260406);
        double r260409 = r260407 + r260408;
        double r260410 = r260404 * r260409;
        double r260411 = r260403 + r260410;
        return r260411;
}

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 2019235 
(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)))))