Data.Colour.CIE:cieLAB from colour-2.3.3, A

Average Error: 0.2 → 0.2

Time: 10.5s

Precision: 64

Math

\[\left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y\]

↓

\[\left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y\]

C

double f(double x, double y) {
        double r556248 = x;
        double r556249 = 16.0;
        double r556250 = 116.0;
        double r556251 = r556249 / r556250;
        double r556252 = r556248 - r556251;
        double r556253 = 3.0;
        double r556254 = r556252 * r556253;
        double r556255 = y;
        double r556256 = r556254 * r556255;
        return r556256;
}

↓

double f(double x, double y) {
        double r556257 = x;
        double r556258 = 16.0;
        double r556259 = 116.0;
        double r556260 = r556258 / r556259;
        double r556261 = r556257 - r556260;
        double r556262 = 3.0;
        double r556263 = r556261 * r556262;
        double r556264 = y;
        double r556265 = r556263 * r556264;
        return r556265;
}

Error

Bits error versus x

Bits error versus y

Target

Original	0.2
Target	0.2
Herbie	0.2

\[y \cdot \left(x \cdot 3 - 0.4137931034482758563264326312491903081536\right)\]

Derivation

1. Initial program 0.2

   \[\left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y\]

2. Final simplification 0.2

   \[\leadsto \left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y\]

Reproduce

herbie shell --seed 2019298 
(FPCore (x y)
  :name "Data.Colour.CIE:cieLAB from colour-2.3.3, A"
  :precision binary64

  :herbie-target
  (* y (- (* x 3) 0.413793103448275856))

  (* (* (- x (/ 16 116)) 3) y))