
(FPCore (v) :precision binary64 (* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))
double code(double v) {
return ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
real(8) function code(v)
real(8), intent (in) :: v
code = ((sqrt(2.0d0) / 4.0d0) * sqrt((1.0d0 - (3.0d0 * (v * v))))) * (1.0d0 - (v * v))
end function
public static double code(double v) {
return ((Math.sqrt(2.0) / 4.0) * Math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
def code(v): return ((math.sqrt(2.0) / 4.0) * math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v))
function code(v) return Float64(Float64(Float64(sqrt(2.0) / 4.0) * sqrt(Float64(1.0 - Float64(3.0 * Float64(v * v))))) * Float64(1.0 - Float64(v * v))) end
function tmp = code(v) tmp = ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v)); end
code[v_] := N[(N[(N[(N[Sqrt[2.0], $MachinePrecision] / 4.0), $MachinePrecision] * N[Sqrt[N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (v) :precision binary64 (* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))
double code(double v) {
return ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
real(8) function code(v)
real(8), intent (in) :: v
code = ((sqrt(2.0d0) / 4.0d0) * sqrt((1.0d0 - (3.0d0 * (v * v))))) * (1.0d0 - (v * v))
end function
public static double code(double v) {
return ((Math.sqrt(2.0) / 4.0) * Math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v));
}
def code(v): return ((math.sqrt(2.0) / 4.0) * math.sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v))
function code(v) return Float64(Float64(Float64(sqrt(2.0) / 4.0) * sqrt(Float64(1.0 - Float64(3.0 * Float64(v * v))))) * Float64(1.0 - Float64(v * v))) end
function tmp = code(v) tmp = ((sqrt(2.0) / 4.0) * sqrt((1.0 - (3.0 * (v * v))))) * (1.0 - (v * v)); end
code[v_] := N[(N[(N[(N[Sqrt[2.0], $MachinePrecision] / 4.0), $MachinePrecision] * N[Sqrt[N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{\sqrt{2}}{4} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}\right) \cdot \left(1 - v \cdot v\right)
\end{array}
(FPCore (v) :precision binary64 (/ (* (- 1.0 (* v (* v (* v v)))) (sqrt (fma (* v v) -6.0 2.0))) (fma (* v v) 4.0 4.0)))
double code(double v) {
return ((1.0 - (v * (v * (v * v)))) * sqrt(fma((v * v), -6.0, 2.0))) / fma((v * v), 4.0, 4.0);
}
function code(v) return Float64(Float64(Float64(1.0 - Float64(v * Float64(v * Float64(v * v)))) * sqrt(fma(Float64(v * v), -6.0, 2.0))) / fma(Float64(v * v), 4.0, 4.0)) end
code[v_] := N[(N[(N[(1.0 - N[(v * N[(v * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(N[(v * v), $MachinePrecision] * -6.0 + 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(N[(v * v), $MachinePrecision] * 4.0 + 4.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(1 - v \cdot \left(v \cdot \left(v \cdot v\right)\right)\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}{\mathsf{fma}\left(v \cdot v, 4, 4\right)}
\end{array}
Initial program 100.0%
Applied rewrites100.0%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift--.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-sqrt.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-/.f64100.0
Applied rewrites100.0%
(FPCore (v) :precision binary64 (* (* (fma v v -1.0) (sqrt (fma v (* v -6.0) 2.0))) -0.25))
double code(double v) {
return (fma(v, v, -1.0) * sqrt(fma(v, (v * -6.0), 2.0))) * -0.25;
}
function code(v) return Float64(Float64(fma(v, v, -1.0) * sqrt(fma(v, Float64(v * -6.0), 2.0))) * -0.25) end
code[v_] := N[(N[(N[(v * v + -1.0), $MachinePrecision] * N[Sqrt[N[(v * N[(v * -6.0), $MachinePrecision] + 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * -0.25), $MachinePrecision]
\begin{array}{l}
\\
\left(\mathsf{fma}\left(v, v, -1\right) \cdot \sqrt{\mathsf{fma}\left(v, v \cdot -6, 2\right)}\right) \cdot -0.25
\end{array}
Initial program 100.0%
lift-sqrt.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift--.f64N/A
lift-sqrt.f64N/A
associate-*l/N/A
div-invN/A
lower-*.f64N/A
Applied rewrites100.0%
Applied rewrites100.0%
Applied rewrites100.0%
(FPCore (v) :precision binary64 (* (sqrt 2.0) (fma (* v v) -0.625 0.25)))
double code(double v) {
return sqrt(2.0) * fma((v * v), -0.625, 0.25);
}
function code(v) return Float64(sqrt(2.0) * fma(Float64(v * v), -0.625, 0.25)) end
code[v_] := N[(N[Sqrt[2.0], $MachinePrecision] * N[(N[(v * v), $MachinePrecision] * -0.625 + 0.25), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt{2} \cdot \mathsf{fma}\left(v \cdot v, -0.625, 0.25\right)
\end{array}
Initial program 100.0%
Taylor expanded in v around 0
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f64N/A
lower-sqrt.f64N/A
unpow2N/A
associate-*r*N/A
*-commutativeN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f6499.9
Applied rewrites99.9%
Taylor expanded in v around 0
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f64N/A
lower-sqrt.f64N/A
*-commutativeN/A
lower-fma.f64N/A
unpow2N/A
lower-*.f6499.9
Applied rewrites99.9%
(FPCore (v) :precision binary64 (* (sqrt 2.0) 0.25))
double code(double v) {
return sqrt(2.0) * 0.25;
}
real(8) function code(v)
real(8), intent (in) :: v
code = sqrt(2.0d0) * 0.25d0
end function
public static double code(double v) {
return Math.sqrt(2.0) * 0.25;
}
def code(v): return math.sqrt(2.0) * 0.25
function code(v) return Float64(sqrt(2.0) * 0.25) end
function tmp = code(v) tmp = sqrt(2.0) * 0.25; end
code[v_] := N[(N[Sqrt[2.0], $MachinePrecision] * 0.25), $MachinePrecision]
\begin{array}{l}
\\
\sqrt{2} \cdot 0.25
\end{array}
Initial program 100.0%
Taylor expanded in v around 0
lower-*.f64N/A
lower-sqrt.f6499.5
Applied rewrites99.5%
Final simplification99.5%
herbie shell --seed 2024220
(FPCore (v)
:name "Falkner and Boettcher, Appendix B, 2"
:precision binary64
(* (* (/ (sqrt 2.0) 4.0) (sqrt (- 1.0 (* 3.0 (* v v))))) (- 1.0 (* v v))))