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

Average Error: 0.2 → 0.2

Time: 13.5s

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 r529582 = x;
        double r529583 = 16.0;
        double r529584 = 116.0;
        double r529585 = r529583 / r529584;
        double r529586 = r529582 - r529585;
        double r529587 = 3.0;
        double r529588 = r529586 * r529587;
        double r529589 = y;
        double r529590 = r529588 * r529589;
        return r529590;
}

↓

double f(double x, double y) {
        double r529591 = x;
        double r529592 = 16.0;
        double r529593 = 116.0;
        double r529594 = r529592 / r529593;
        double r529595 = r529591 - r529594;
        double r529596 = 3.0;
        double r529597 = r529595 * r529596;
        double r529598 = y;
        double r529599 = r529597 * r529598;
        return r529599;
}

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 2019325 
(FPCore (x y)
  :name "Data.Colour.CIE:cieLAB from colour-2.3.3, A"
  :precision binary64

  :herbie-target
  (* y (- (* x 3) 0.41379310344827586))

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