Average Error: 0.0 → 0
Time: 2.6s
Precision: 64
\[x \cdot y - x\]
\[\mathsf{fma}\left(x, y, -x\right)\]
x \cdot y - x
\mathsf{fma}\left(x, y, -x\right)
double f(double x, double y) {
        double r231080 = x;
        double r231081 = y;
        double r231082 = r231080 * r231081;
        double r231083 = r231082 - r231080;
        return r231083;
}

double f(double x, double y) {
        double r231084 = x;
        double r231085 = y;
        double r231086 = -r231084;
        double r231087 = fma(r231084, r231085, r231086);
        return r231087;
}

Error

Bits error versus x

Bits error versus y

Derivation

  1. Initial program 0.0

    \[x \cdot y - x\]
  2. Using strategy rm
  3. Applied fma-neg0

    \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, -x\right)}\]
  4. Final simplification0

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

Reproduce

herbie shell --seed 2019351 +o rules:numerics
(FPCore (x y)
  :name "Data.Histogram.Bin.LogBinD:$cbinSizeN from histogram-fill-0.8.4.1"
  :precision binary64
  (- (* x y) x))