| Alternative 1 | |
|---|---|
| Accuracy | 99.9% |
| Cost | 7168 |
\[\mathsf{fma}\left(\frac{z + x}{y}, z - x, -y\right) \cdot -0.5
\]

(FPCore (x y z) :precision binary64 (/ (- (+ (* x x) (* y y)) (* z z)) (* y 2.0)))
(FPCore (x y z) :precision binary64 (* (fma (/ (+ z x) y) (- z x) (- y)) -0.5))
double code(double x, double y, double z) {
return (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
}
double code(double x, double y, double z) {
return fma(((z + x) / y), (z - x), -y) * -0.5;
}
function code(x, y, z) return Float64(Float64(Float64(Float64(x * x) + Float64(y * y)) - Float64(z * z)) / Float64(y * 2.0)) end
function code(x, y, z) return Float64(fma(Float64(Float64(z + x) / y), Float64(z - x), Float64(-y)) * -0.5) end
code[x_, y_, z_] := N[(N[(N[(N[(x * x), $MachinePrecision] + N[(y * y), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y * 2.0), $MachinePrecision]), $MachinePrecision]
code[x_, y_, z_] := N[(N[(N[(N[(z + x), $MachinePrecision] / y), $MachinePrecision] * N[(z - x), $MachinePrecision] + (-y)), $MachinePrecision] * -0.5), $MachinePrecision]
\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2}
\mathsf{fma}\left(\frac{z + x}{y}, z - x, -y\right) \cdot -0.5
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
| Original | 69.0% |
|---|---|
| Target | 99.9% |
| Herbie | 99.9% |
Initial program 72.6%
Simplified99.9%
[Start]72.6% | \[ \frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2}
\] |
|---|---|
sub-neg [=>]72.6% | \[ \frac{\color{blue}{\left(x \cdot x + y \cdot y\right) + \left(-z \cdot z\right)}}{y \cdot 2}
\] |
+-commutative [=>]72.6% | \[ \frac{\color{blue}{\left(-z \cdot z\right) + \left(x \cdot x + y \cdot y\right)}}{y \cdot 2}
\] |
neg-sub0 [=>]72.6% | \[ \frac{\color{blue}{\left(0 - z \cdot z\right)} + \left(x \cdot x + y \cdot y\right)}{y \cdot 2}
\] |
associate-+l- [=>]72.6% | \[ \frac{\color{blue}{0 - \left(z \cdot z - \left(x \cdot x + y \cdot y\right)\right)}}{y \cdot 2}
\] |
sub0-neg [=>]72.6% | \[ \frac{\color{blue}{-\left(z \cdot z - \left(x \cdot x + y \cdot y\right)\right)}}{y \cdot 2}
\] |
neg-mul-1 [=>]72.6% | \[ \frac{\color{blue}{-1 \cdot \left(z \cdot z - \left(x \cdot x + y \cdot y\right)\right)}}{y \cdot 2}
\] |
*-commutative [=>]72.6% | \[ \frac{\color{blue}{\left(z \cdot z - \left(x \cdot x + y \cdot y\right)\right) \cdot -1}}{y \cdot 2}
\] |
times-frac [=>]72.7% | \[ \color{blue}{\frac{z \cdot z - \left(x \cdot x + y \cdot y\right)}{y} \cdot \frac{-1}{2}}
\] |
associate--r+ [=>]72.7% | \[ \frac{\color{blue}{\left(z \cdot z - x \cdot x\right) - y \cdot y}}{y} \cdot \frac{-1}{2}
\] |
div-sub [=>]72.7% | \[ \color{blue}{\left(\frac{z \cdot z - x \cdot x}{y} - \frac{y \cdot y}{y}\right)} \cdot \frac{-1}{2}
\] |
difference-of-squares [=>]77.0% | \[ \left(\frac{\color{blue}{\left(z + x\right) \cdot \left(z - x\right)}}{y} - \frac{y \cdot y}{y}\right) \cdot \frac{-1}{2}
\] |
+-commutative [<=]77.0% | \[ \left(\frac{\color{blue}{\left(x + z\right)} \cdot \left(z - x\right)}{y} - \frac{y \cdot y}{y}\right) \cdot \frac{-1}{2}
\] |
associate-*l/ [<=]79.2% | \[ \left(\color{blue}{\frac{x + z}{y} \cdot \left(z - x\right)} - \frac{y \cdot y}{y}\right) \cdot \frac{-1}{2}
\] |
*-commutative [=>]79.2% | \[ \left(\color{blue}{\left(z - x\right) \cdot \frac{x + z}{y}} - \frac{y \cdot y}{y}\right) \cdot \frac{-1}{2}
\] |
associate-/l* [=>]99.9% | \[ \left(\left(z - x\right) \cdot \frac{x + z}{y} - \color{blue}{\frac{y}{\frac{y}{y}}}\right) \cdot \frac{-1}{2}
\] |
*-inverses [=>]99.9% | \[ \left(\left(z - x\right) \cdot \frac{x + z}{y} - \frac{y}{\color{blue}{1}}\right) \cdot \frac{-1}{2}
\] |
/-rgt-identity [=>]99.9% | \[ \left(\left(z - x\right) \cdot \frac{x + z}{y} - \color{blue}{y}\right) \cdot \frac{-1}{2}
\] |
metadata-eval [=>]99.9% | \[ \left(\left(z - x\right) \cdot \frac{x + z}{y} - y\right) \cdot \color{blue}{-0.5}
\] |
Applied egg-rr99.9%
[Start]99.9% | \[ \left(\left(z - x\right) \cdot \frac{x + z}{y} - y\right) \cdot -0.5
\] |
|---|---|
*-commutative [=>]99.9% | \[ \left(\color{blue}{\frac{x + z}{y} \cdot \left(z - x\right)} - y\right) \cdot -0.5
\] |
fma-neg [=>]99.9% | \[ \color{blue}{\mathsf{fma}\left(\frac{x + z}{y}, z - x, -y\right)} \cdot -0.5
\] |
+-commutative [=>]99.9% | \[ \mathsf{fma}\left(\frac{\color{blue}{z + x}}{y}, z - x, -y\right) \cdot -0.5
\] |
Final simplification99.9%
| Alternative 1 | |
|---|---|
| Accuracy | 99.9% |
| Cost | 7168 |
| Alternative 2 | |
|---|---|
| Accuracy | 52.8% |
| Cost | 1108 |
| Alternative 3 | |
|---|---|
| Accuracy | 52.9% |
| Cost | 1108 |
| Alternative 4 | |
|---|---|
| Accuracy | 52.8% |
| Cost | 1108 |
| Alternative 5 | |
|---|---|
| Accuracy | 85.2% |
| Cost | 1101 |
| Alternative 6 | |
|---|---|
| Accuracy | 85.3% |
| Cost | 1100 |
| Alternative 7 | |
|---|---|
| Accuracy | 85.5% |
| Cost | 900 |
| Alternative 8 | |
|---|---|
| Accuracy | 79.0% |
| Cost | 836 |
| Alternative 9 | |
|---|---|
| Accuracy | 99.9% |
| Cost | 832 |
| Alternative 10 | |
|---|---|
| Accuracy | 53.5% |
| Cost | 713 |
| Alternative 11 | |
|---|---|
| Accuracy | 34.8% |
| Cost | 192 |
herbie shell --seed 2023272
(FPCore (x y z)
:name "Diagrams.TwoD.Apollonian:initialConfig from diagrams-contrib-1.3.0.5, A"
:precision binary64
:herbie-target
(- (* y 0.5) (* (* (/ 0.5 y) (+ z x)) (- z x)))
(/ (- (+ (* x x) (* y y)) (* z z)) (* y 2.0)))