Average Error: 16.4 → 0.0
Time: 10.8s
Precision: 64
\[x + \left(1 - x\right) \cdot \left(1 - y\right)\]
↓
\[\mathsf{fma}\left(y, x - 1, 1\right)\]
x + \left(1 - x\right) \cdot \left(1 - y\right)
↓
\mathsf{fma}\left(y, x - 1, 1\right)
double f(double x, double y) {
        double r22549621 = x;
        double r22549622 = 1.0;
        double r22549623 = r22549622 - r22549621;
        double r22549624 = y;
        double r22549625 = r22549622 - r22549624;
        double r22549626 = r22549623 * r22549625;
        double r22549627 = r22549621 + r22549626;
        return r22549627;
}
↓
double f(double x, double y) {
        double r22549628 = y;
        double r22549629 = x;
        double r22549630 = 1.0;
        double r22549631 = r22549629 - r22549630;
        double r22549632 = fma(r22549628, r22549631, r22549630);
        return r22549632;
}

Error

Bits error versus x

Bits error versus y

Target

Original16.4
Target0.0
Herbie0.0
\[y \cdot x - \left(y - 1\right)\]

Derivation

  1. Initial program 16.4

    \[x + \left(1 - x\right) \cdot \left(1 - y\right)\]

  2. Simplified16.4

    \[\leadsto \color{blue}{\mathsf{fma}\left(1 - y, 1 - x, x\right)}\]

  3. Taylor expanded around 0 0.0

    \[\leadsto \color{blue}{\left(1 + x \cdot y\right) - 1 \cdot y}\]

  4. Simplified0.0

    \[\leadsto \color{blue}{\mathsf{fma}\left(y, x - 1, 1\right)}\]

  5. Final simplification0.0

    \[\leadsto \mathsf{fma}\left(y, x - 1, 1\right)\]

Reproduce

herbie shell --seed 2019172 +o rules:numerics
(FPCore (x y)
  :name "Graphics.Rendering.Chart.Plot.Vectors:renderPlotVectors from Chart-1.5.3"

  :herbie-target
  (- (* y x) (- y 1.0))

  (+ x (* (- 1.0 x) (- 1.0 y))))