Average Error: 0.1 → 0.1
Time: 5.4s
Precision: binary64
\[\left(\left(x \cdot y + z \cdot z\right) + z \cdot z\right) + z \cdot z \]
↓
\[\mathsf{fma}\left(z, z, \mathsf{fma}\left(x, y, \left(z \cdot z\right) \cdot 2\right)\right) \]
\left(\left(x \cdot y + z \cdot z\right) + z \cdot z\right) + z \cdot z
↓
\mathsf{fma}\left(z, z, \mathsf{fma}\left(x, y, \left(z \cdot z\right) \cdot 2\right)\right)

(FPCore (x y z)
 :precision binary64
 (+ (+ (+ (* x y) (* z z)) (* z z)) (* z z)))
↓
(FPCore (x y z) :precision binary64 (fma z z (fma x y (* (* z z) 2.0))))
double code(double x, double y, double z) {
	return (((x * y) + (z * z)) + (z * z)) + (z * z);
}
↓
double code(double x, double y, double z) {
	return fma(z, z, fma(x, y, ((z * z) * 2.0)));
}

Error

Bits error versus x

Bits error versus y

Bits error versus z

Target

Original0.1
Target0.1
Herbie0.1
\[\left(3 \cdot z\right) \cdot z + y \cdot x \]

Derivation

  1. Initial program 0.1

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

  2. Applied egg-rr0.1

    \[\leadsto \color{blue}{\mathsf{fma}\left(z, z, \mathsf{fma}\left(x, y, \left(z \cdot z\right) \cdot 2\right)\right)} \]

  3. Final simplification0.1

    \[\leadsto \mathsf{fma}\left(z, z, \mathsf{fma}\left(x, y, \left(z \cdot z\right) \cdot 2\right)\right) \]

Reproduce

herbie shell --seed 2022130 
(FPCore (x y z)
  :name "Linear.Quaternion:$c/ from linear-1.19.1.3, A"
  :precision binary64

  :herbie-target
  (+ (* (* 3.0 z) z) (* y x))

  (+ (+ (+ (* x y) (* z z)) (* z z)) (* z z)))