Diagrams.Solve.Polynomial:quartForm from diagrams-solve-0.1, A

Average Error: 0.1 → 0

Time: 3.4s

Precision: 64

• Falling back on racket egraph because egg-herbie package not installed

Math

\[x - \frac{3}{8} \cdot y\]

↓

\[\mathsf{fma}\left(-\frac{3}{8}, y, x\right)\]

C

double f(double x, double y) {
        double r31397 = x;
        double r31398 = 3.0;
        double r31399 = 8.0;
        double r31400 = r31398 / r31399;
        double r31401 = y;
        double r31402 = r31400 * r31401;
        double r31403 = r31397 - r31402;
        return r31403;
}

↓

double f(double x, double y) {
        double r31404 = 3.0;
        double r31405 = 8.0;
        double r31406 = r31404 / r31405;
        double r31407 = -r31406;
        double r31408 = y;
        double r31409 = x;
        double r31410 = fma(r31407, r31408, r31409);
        return r31410;
}

Error

Bits error versus x

Bits error versus y

Derivation

1. Initial program 0.1

   \[x - \frac{3}{8} \cdot y\]
2. Using strategy rm

3. Applied add-cube-cbrt 0.8

   \[\leadsto \color{blue}{\left(\sqrt[3]{x} \cdot \sqrt[3]{x}\right) \cdot \sqrt[3]{x}} - \frac{3}{8} \cdot y\]

4. Applied prod-diff 0.8

   \[\leadsto \color{blue}{\mathsf{fma}\left(\sqrt[3]{x} \cdot \sqrt[3]{x}, \sqrt[3]{x}, -y \cdot \frac{3}{8}\right) + \mathsf{fma}\left(-y, \frac{3}{8}, y \cdot \frac{3}{8}\right)}\]

5. Simplified 0.1

   \[\leadsto \color{blue}{\mathsf{fma}\left(-\frac{3}{8}, y, x\right)} + \mathsf{fma}\left(-y, \frac{3}{8}, y \cdot \frac{3}{8}\right)\]

6. Simplified 0

   \[\leadsto \mathsf{fma}\left(-\frac{3}{8}, y, x\right) + \color{blue}{0}\]

7. Final simplification 0

   \[\leadsto \mathsf{fma}\left(-\frac{3}{8}, y, x\right)\]

Reproduce

herbie shell --seed 2020045 +o rules:numerics
(FPCore (x y)
  :name "Diagrams.Solve.Polynomial:quartForm  from diagrams-solve-0.1, A"
  :precision binary64
  (- x (* (/ 3 8) y)))