Average Error: 0.5 → 0.3
Time: 9.3s
Precision: 64
\[\frac{\left(\frac{\left(d1 \cdot \left(3\right)\right)}{\left(d1 \cdot d2\right)}\right)}{\left(d1 \cdot d3\right)}\]
↓
\[\left(\left(3 + d2\right) + d3\right) \cdot d1\]
\frac{\left(\frac{\left(d1 \cdot \left(3\right)\right)}{\left(d1 \cdot d2\right)}\right)}{\left(d1 \cdot d3\right)}
↓
\left(\left(3 + d2\right) + d3\right) \cdot d1
double f(double d1, double d2, double d3) {
        double r4986707 = d1;
        double r4986708 = 3.0;
        double r4986709 = /* ERROR: no posit support in C */;
        double r4986710 = r4986707 * r4986709;
        double r4986711 = d2;
        double r4986712 = r4986707 * r4986711;
        double r4986713 = r4986710 + r4986712;
        double r4986714 = d3;
        double r4986715 = r4986707 * r4986714;
        double r4986716 = r4986713 + r4986715;
        return r4986716;
}
↓
double f(double d1, double d2, double d3) {
        double r4986717 = 3.0;
        double r4986718 = d2;
        double r4986719 = r4986717 + r4986718;
        double r4986720 = d3;
        double r4986721 = r4986719 + r4986720;
        double r4986722 = d1;
        double r4986723 = r4986721 * r4986722;
        return r4986723;
}

Error

Bits error versus d1

Bits error versus d2

Bits error versus d3

Derivation

  1. Initial program 0.5

    \[\frac{\left(\frac{\left(d1 \cdot \left(3\right)\right)}{\left(d1 \cdot d2\right)}\right)}{\left(d1 \cdot d3\right)}\]

  2. Simplified0.3

    \[\leadsto \color{blue}{\left(\frac{\left(3\right)}{\left(\frac{d2}{d3}\right)}\right) \cdot d1}\]
  3. Using strategy rm

  4. Applied associate-+r+0.3

    \[\leadsto \color{blue}{\left(\frac{\left(\frac{\left(3\right)}{d2}\right)}{d3}\right)} \cdot d1\]

  5. Final simplification0.3

    \[\leadsto \left(\left(3 + d2\right) + d3\right) \cdot d1\]

Reproduce

herbie shell --seed 2019130 +o rules:numerics
(FPCore (d1 d2 d3)
  :name "FastMath test3"
  (+.p16 (+.p16 (*.p16 d1 (real->posit16 3)) (*.p16 d1 d2)) (*.p16 d1 d3)))