Average Error: 0.0 → 0
Time: 1.6s
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 r246070 = x;
        double r246071 = y;
        double r246072 = r246070 * r246071;
        double r246073 = r246072 - r246070;
        return r246073;
}

double f(double x, double y) {
        double r246074 = x;
        double r246075 = y;
        double r246076 = -r246074;
        double r246077 = fma(r246074, r246075, r246076);
        return r246077;
}

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 2020047 +o rules:numerics
(FPCore (x y)
  :name "Data.Histogram.Bin.LogBinD:$cbinSizeN from histogram-fill-0.8.4.1"
  :precision binary64
  (- (* x y) x))