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

Average Error: 0.2 → 0.2

Time: 14.8s

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 r57392946 = x;
        double r57392947 = 16.0;
        double r57392948 = 116.0;
        double r57392949 = r57392947 / r57392948;
        double r57392950 = r57392946 - r57392949;
        double r57392951 = 3.0;
        double r57392952 = r57392950 * r57392951;
        double r57392953 = y;
        double r57392954 = r57392952 * r57392953;
        return r57392954;
}

↓

double f(double x, double y) {
        double r57392955 = x;
        double r57392956 = 16.0;
        double r57392957 = 116.0;
        double r57392958 = r57392956 / r57392957;
        double r57392959 = r57392955 - r57392958;
        double r57392960 = 3.0;
        double r57392961 = r57392959 * r57392960;
        double r57392962 = y;
        double r57392963 = r57392961 * r57392962;
        return r57392963;
}

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 2019174 
(FPCore (x y)
  :name "Data.Colour.CIE:cieLAB from colour-2.3.3, A"

  :herbie-target
  (* y (- (* x 3.0) 0.41379310344827586))

  (* (* (- x (/ 16.0 116.0)) 3.0) y))