Expression 2, p15

Average Error: 0.0 → 0

Time: 13.9s

Precision: 64

\[0 \le x \le 2\]

Math

\[x + x \cdot x\]

↓

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

C

double f(double x) {
        double r1556671 = x;
        double r1556672 = r1556671 * r1556671;
        double r1556673 = r1556671 + r1556672;
        return r1556673;
}

↓

double f(double x) {
        double r1556674 = x;
        double r1556675 = fma(r1556674, r1556674, r1556674);
        return r1556675;
}

Error

Bits error versus x

Target

Original	0.0
Target	0.0
Herbie	0

\[\left(1.0 + x\right) \cdot x\]

Derivation

1. Initial program 0.0

   \[x + x \cdot x\]

2. Simplified 0

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

3. Final simplification 0

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

Reproduce

herbie shell --seed 2019151 +o rules:numerics
(FPCore (x)
  :name "Expression 2, p15"
  :pre (<= 0 x 2)

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

  (+ x (* x x)))