Average Error: 0.5 → 0.3
Time: 9.2s
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 r6476141 = d1;
        double r6476142 = 3.0;
        double r6476143 = /* ERROR: no posit support in C */;
        double r6476144 = r6476141 * r6476143;
        double r6476145 = d2;
        double r6476146 = r6476141 * r6476145;
        double r6476147 = r6476144 + r6476146;
        double r6476148 = d3;
        double r6476149 = r6476141 * r6476148;
        double r6476150 = r6476147 + r6476149;
        return r6476150;
}
↓
double f(double d1, double d2, double d3) {
        double r6476151 = 3.0;
        double r6476152 = d2;
        double r6476153 = r6476151 + r6476152;
        double r6476154 = d3;
        double r6476155 = r6476153 + r6476154;
        double r6476156 = d1;
        double r6476157 = r6476155 * r6476156;
        return r6476157;
}

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 2019135 +o rules:numerics
(FPCore (d1 d2 d3)
  :name "FastMath test3"
  (+.p16 (+.p16 (*.p16 d1 (real->posit16 3)) (*.p16 d1 d2)) (*.p16 d1 d3)))