Average Error: 0.0 → 0.0
Time: 7.2s
Precision: 64
\[0 \le x \le 2\]
\[x \cdot \left(x \cdot x\right) + x \cdot x\]
↓
\[x \cdot \mathsf{fma}\left(x, x, x\right)\]
x \cdot \left(x \cdot x\right) + x \cdot x
↓
x \cdot \mathsf{fma}\left(x, x, x\right)
double f(double x) {
        double r2624350 = x;
        double r2624351 = r2624350 * r2624350;
        double r2624352 = r2624350 * r2624351;
        double r2624353 = r2624352 + r2624351;
        return r2624353;
}
↓
double f(double x) {
        double r2624354 = x;
        double r2624355 = fma(r2624354, r2624354, r2624354);
        double r2624356 = r2624354 * r2624355;
        return r2624356;
}

Error

Bits error versus x

Target

Original0.0
Target0.0
Herbie0.0
\[\left(\left(1.0 + x\right) \cdot x\right) \cdot x\]

Derivation

  1. Initial program 0.0

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

  2. Simplified0.0

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

  3. Taylor expanded around -inf 0.0

    \[\leadsto \color{blue}{{x}^{3} + {x}^{2}}\]

  4. Simplified0.0

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

  5. Final simplification0.0

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

Reproduce

herbie shell --seed 2019135 +o rules:numerics
(FPCore (x)
  :name "Expression 3, p15"
  :pre (<= 0 x 2)

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

  (+ (* x (* x x)) (* x x)))