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

Average Error: 0.1 → 0.1

Time: 15.7s

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 r832175 = x;
        double r832176 = 0.5;
        double r832177 = r832175 * r832176;
        double r832178 = y;
        double r832179 = 1.0;
        double r832180 = z;
        double r832181 = r832179 - r832180;
        double r832182 = log(r832180);
        double r832183 = r832181 + r832182;
        double r832184 = r832178 * r832183;
        double r832185 = r832177 + r832184;
        return r832185;
}

↓

double f(double x, double y, double z) {
        double r832186 = x;
        double r832187 = 0.5;
        double r832188 = r832186 * r832187;
        double r832189 = y;
        double r832190 = 1.0;
        double r832191 = z;
        double r832192 = r832190 - r832191;
        double r832193 = log(r832191);
        double r832194 = r832192 + r832193;
        double r832195 = r832189 * r832194;
        double r832196 = r832188 + r832195;
        return r832196;
}

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 2019209 
(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)))))