Average Error: 0.1 → 0.1
Time: 3.3s
Precision: binary64
\[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
↓
\[\mathsf{fma}\left({\left(\sqrt[3]{y}\right)}^{2}, \sqrt[3]{y}, \log y \cdot \left(-0.5 - y\right)\right) + \left(x - z\right) \]
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
↓
(FPCore (x y z)
 :precision binary64
 (+ (fma (pow (cbrt y) 2.0) (cbrt y) (* (log y) (- -0.5 y))) (- x z)))
double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * log(y))) + y) - z;
}
↓
double code(double x, double y, double z) {
	return fma(pow(cbrt(y), 2.0), cbrt(y), (log(y) * (-0.5 - y))) + (x - z);
}

function code(x, y, z)
	return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z)
end
↓
function code(x, y, z)
	return Float64(fma((cbrt(y) ^ 2.0), cbrt(y), Float64(log(y) * Float64(-0.5 - y))) + Float64(x - z))
end

code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
↓
code[x_, y_, z_] := N[(N[(N[Power[N[Power[y, 1/3], $MachinePrecision], 2.0], $MachinePrecision] * N[Power[y, 1/3], $MachinePrecision] + N[(N[Log[y], $MachinePrecision] * N[(-0.5 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(x - z), $MachinePrecision]), $MachinePrecision]

\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z
↓
\mathsf{fma}\left({\left(\sqrt[3]{y}\right)}^{2}, \sqrt[3]{y}, \log y \cdot \left(-0.5 - y\right)\right) + \left(x - z\right)

Error

Bits error versus x

Bits error versus y

Bits error versus z

Target

Original0.1
Target0.1
Herbie0.1
\[\left(\left(y + x\right) - z\right) - \left(y + 0.5\right) \cdot \log y \]

Derivation

  1. Initial program 0.1

    \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]

  2. Simplified0.1

    \[\leadsto \color{blue}{\mathsf{fma}\left(\log y, -0.5 - y, y\right) + \left(x - z\right)} \]

  3. Applied egg-rr0.5

    \[\leadsto \color{blue}{{\left(\sqrt[3]{\mathsf{fma}\left(\log y, -0.5 - y, y\right)}\right)}^{3}} + \left(x - z\right) \]

  4. Applied egg-rr0.1

    \[\leadsto \color{blue}{\mathsf{fma}\left({\left(\sqrt[3]{y}\right)}^{2}, \sqrt[3]{y}, \log y \cdot \left(-0.5 - y\right)\right)} + \left(x - z\right) \]

  5. Final simplification0.1

    \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{y}\right)}^{2}, \sqrt[3]{y}, \log y \cdot \left(-0.5 - y\right)\right) + \left(x - z\right) \]

Reproduce

herbie shell --seed 2022162 
(FPCore (x y z)
  :name "Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2"
  :precision binary64

  :herbie-target
  (- (- (+ y x) z) (* (+ y 0.5) (log y)))

  (- (+ (- x (* (+ y 0.5) (log y))) y) z))