
(FPCore (x l t) :precision binary64 (/ (* (sqrt 2.0) t) (sqrt (- (* (/ (+ x 1.0) (- x 1.0)) (+ (* l l) (* 2.0 (* t t)))) (* l l)))))
double code(double x, double l, double t) {
return (sqrt(2.0) * t) / sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)));
}
real(8) function code(x, l, t)
real(8), intent (in) :: x
real(8), intent (in) :: l
real(8), intent (in) :: t
code = (sqrt(2.0d0) * t) / sqrt(((((x + 1.0d0) / (x - 1.0d0)) * ((l * l) + (2.0d0 * (t * t)))) - (l * l)))
end function
public static double code(double x, double l, double t) {
return (Math.sqrt(2.0) * t) / Math.sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)));
}
def code(x, l, t): return (math.sqrt(2.0) * t) / math.sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)))
function code(x, l, t) return Float64(Float64(sqrt(2.0) * t) / sqrt(Float64(Float64(Float64(Float64(x + 1.0) / Float64(x - 1.0)) * Float64(Float64(l * l) + Float64(2.0 * Float64(t * t)))) - Float64(l * l)))) end
function tmp = code(x, l, t) tmp = (sqrt(2.0) * t) / sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l))); end
code[x_, l_, t_] := N[(N[(N[Sqrt[2.0], $MachinePrecision] * t), $MachinePrecision] / N[Sqrt[N[(N[(N[(N[(x + 1.0), $MachinePrecision] / N[(x - 1.0), $MachinePrecision]), $MachinePrecision] * N[(N[(l * l), $MachinePrecision] + N[(2.0 * N[(t * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(l * l), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\sqrt{2} \cdot t}{\sqrt{\frac{x + 1}{x - 1} \cdot \left(\ell \cdot \ell + 2 \cdot \left(t \cdot t\right)\right) - \ell \cdot \ell}}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x l t) :precision binary64 (/ (* (sqrt 2.0) t) (sqrt (- (* (/ (+ x 1.0) (- x 1.0)) (+ (* l l) (* 2.0 (* t t)))) (* l l)))))
double code(double x, double l, double t) {
return (sqrt(2.0) * t) / sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)));
}
real(8) function code(x, l, t)
real(8), intent (in) :: x
real(8), intent (in) :: l
real(8), intent (in) :: t
code = (sqrt(2.0d0) * t) / sqrt(((((x + 1.0d0) / (x - 1.0d0)) * ((l * l) + (2.0d0 * (t * t)))) - (l * l)))
end function
public static double code(double x, double l, double t) {
return (Math.sqrt(2.0) * t) / Math.sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)));
}
def code(x, l, t): return (math.sqrt(2.0) * t) / math.sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l)))
function code(x, l, t) return Float64(Float64(sqrt(2.0) * t) / sqrt(Float64(Float64(Float64(Float64(x + 1.0) / Float64(x - 1.0)) * Float64(Float64(l * l) + Float64(2.0 * Float64(t * t)))) - Float64(l * l)))) end
function tmp = code(x, l, t) tmp = (sqrt(2.0) * t) / sqrt(((((x + 1.0) / (x - 1.0)) * ((l * l) + (2.0 * (t * t)))) - (l * l))); end
code[x_, l_, t_] := N[(N[(N[Sqrt[2.0], $MachinePrecision] * t), $MachinePrecision] / N[Sqrt[N[(N[(N[(N[(x + 1.0), $MachinePrecision] / N[(x - 1.0), $MachinePrecision]), $MachinePrecision] * N[(N[(l * l), $MachinePrecision] + N[(2.0 * N[(t * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(l * l), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\sqrt{2} \cdot t}{\sqrt{\frac{x + 1}{x - 1} \cdot \left(\ell \cdot \ell + 2 \cdot \left(t \cdot t\right)\right) - \ell \cdot \ell}}
\end{array}
l_m = (fabs.f64 l)
t\_m = (fabs.f64 t)
t\_s = (copysign.f64 #s(literal 1 binary64) t)
(FPCore (t_s x l_m t_m)
:precision binary64
(let* ((t_2 (* (sqrt 2.0) t_m)))
(*
t_s
(if (<= (* l_m l_m) 1e+276)
(/ t_2 (* t_2 (sqrt (/ (+ x 1.0) (+ x -1.0)))))
(/ t_2 (* l_m (sqrt (/ 2.0 x))))))))l_m = fabs(l);
t\_m = fabs(t);
t\_s = copysign(1.0, t);
double code(double t_s, double x, double l_m, double t_m) {
double t_2 = sqrt(2.0) * t_m;
double tmp;
if ((l_m * l_m) <= 1e+276) {
tmp = t_2 / (t_2 * sqrt(((x + 1.0) / (x + -1.0))));
} else {
tmp = t_2 / (l_m * sqrt((2.0 / x)));
}
return t_s * tmp;
}
l_m = abs(l)
t\_m = abs(t)
t\_s = copysign(1.0d0, t)
real(8) function code(t_s, x, l_m, t_m)
real(8), intent (in) :: t_s
real(8), intent (in) :: x
real(8), intent (in) :: l_m
real(8), intent (in) :: t_m
real(8) :: t_2
real(8) :: tmp
t_2 = sqrt(2.0d0) * t_m
if ((l_m * l_m) <= 1d+276) then
tmp = t_2 / (t_2 * sqrt(((x + 1.0d0) / (x + (-1.0d0)))))
else
tmp = t_2 / (l_m * sqrt((2.0d0 / x)))
end if
code = t_s * tmp
end function
l_m = Math.abs(l);
t\_m = Math.abs(t);
t\_s = Math.copySign(1.0, t);
public static double code(double t_s, double x, double l_m, double t_m) {
double t_2 = Math.sqrt(2.0) * t_m;
double tmp;
if ((l_m * l_m) <= 1e+276) {
tmp = t_2 / (t_2 * Math.sqrt(((x + 1.0) / (x + -1.0))));
} else {
tmp = t_2 / (l_m * Math.sqrt((2.0 / x)));
}
return t_s * tmp;
}
l_m = math.fabs(l) t\_m = math.fabs(t) t\_s = math.copysign(1.0, t) def code(t_s, x, l_m, t_m): t_2 = math.sqrt(2.0) * t_m tmp = 0 if (l_m * l_m) <= 1e+276: tmp = t_2 / (t_2 * math.sqrt(((x + 1.0) / (x + -1.0)))) else: tmp = t_2 / (l_m * math.sqrt((2.0 / x))) return t_s * tmp
l_m = abs(l) t\_m = abs(t) t\_s = copysign(1.0, t) function code(t_s, x, l_m, t_m) t_2 = Float64(sqrt(2.0) * t_m) tmp = 0.0 if (Float64(l_m * l_m) <= 1e+276) tmp = Float64(t_2 / Float64(t_2 * sqrt(Float64(Float64(x + 1.0) / Float64(x + -1.0))))); else tmp = Float64(t_2 / Float64(l_m * sqrt(Float64(2.0 / x)))); end return Float64(t_s * tmp) end
l_m = abs(l); t\_m = abs(t); t\_s = sign(t) * abs(1.0); function tmp_2 = code(t_s, x, l_m, t_m) t_2 = sqrt(2.0) * t_m; tmp = 0.0; if ((l_m * l_m) <= 1e+276) tmp = t_2 / (t_2 * sqrt(((x + 1.0) / (x + -1.0)))); else tmp = t_2 / (l_m * sqrt((2.0 / x))); end tmp_2 = t_s * tmp; end
l_m = N[Abs[l], $MachinePrecision]
t\_m = N[Abs[t], $MachinePrecision]
t\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[t]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[t$95$s_, x_, l$95$m_, t$95$m_] := Block[{t$95$2 = N[(N[Sqrt[2.0], $MachinePrecision] * t$95$m), $MachinePrecision]}, N[(t$95$s * If[LessEqual[N[(l$95$m * l$95$m), $MachinePrecision], 1e+276], N[(t$95$2 / N[(t$95$2 * N[Sqrt[N[(N[(x + 1.0), $MachinePrecision] / N[(x + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(t$95$2 / N[(l$95$m * N[Sqrt[N[(2.0 / x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]]
\begin{array}{l}
l_m = \left|\ell\right|
\\
t\_m = \left|t\right|
\\
t\_s = \mathsf{copysign}\left(1, t\right)
\\
\begin{array}{l}
t_2 := \sqrt{2} \cdot t\_m\\
t\_s \cdot \begin{array}{l}
\mathbf{if}\;l\_m \cdot l\_m \leq 10^{+276}:\\
\;\;\;\;\frac{t\_2}{t\_2 \cdot \sqrt{\frac{x + 1}{x + -1}}}\\
\mathbf{else}:\\
\;\;\;\;\frac{t\_2}{l\_m \cdot \sqrt{\frac{2}{x}}}\\
\end{array}
\end{array}
\end{array}
if (*.f64 l l) < 1.0000000000000001e276Initial program 40.1%
Taylor expanded in l around 0
lower-*.f64N/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
lower-/.f64N/A
lower-+.f64N/A
sub-negN/A
metadata-evalN/A
lower-+.f6483.2
Applied rewrites83.2%
if 1.0000000000000001e276 < (*.f64 l l) Initial program 0.0%
Applied rewrites0.0%
Taylor expanded in l around inf
lower-*.f64N/A
lower-sqrt.f64N/A
sub-negN/A
metadata-evalN/A
lower-+.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-+.f64N/A
lower-+.f64N/A
sub-negN/A
unpow2N/A
metadata-evalN/A
lower-fma.f643.2
Applied rewrites3.2%
Taylor expanded in x around inf
Applied rewrites74.7%
Final simplification81.7%
l_m = (fabs.f64 l)
t\_m = (fabs.f64 t)
t\_s = (copysign.f64 #s(literal 1 binary64) t)
(FPCore (t_s x l_m t_m)
:precision binary64
(let* ((t_2 (* (sqrt 2.0) t_m)))
(*
t_s
(if (<= (* l_m l_m) 1e+276)
(/ t_2 (* t_m (sqrt (/ (fma x 2.0 2.0) (+ x -1.0)))))
(/ t_2 (* l_m (sqrt (/ 2.0 x))))))))l_m = fabs(l);
t\_m = fabs(t);
t\_s = copysign(1.0, t);
double code(double t_s, double x, double l_m, double t_m) {
double t_2 = sqrt(2.0) * t_m;
double tmp;
if ((l_m * l_m) <= 1e+276) {
tmp = t_2 / (t_m * sqrt((fma(x, 2.0, 2.0) / (x + -1.0))));
} else {
tmp = t_2 / (l_m * sqrt((2.0 / x)));
}
return t_s * tmp;
}
l_m = abs(l) t\_m = abs(t) t\_s = copysign(1.0, t) function code(t_s, x, l_m, t_m) t_2 = Float64(sqrt(2.0) * t_m) tmp = 0.0 if (Float64(l_m * l_m) <= 1e+276) tmp = Float64(t_2 / Float64(t_m * sqrt(Float64(fma(x, 2.0, 2.0) / Float64(x + -1.0))))); else tmp = Float64(t_2 / Float64(l_m * sqrt(Float64(2.0 / x)))); end return Float64(t_s * tmp) end
l_m = N[Abs[l], $MachinePrecision]
t\_m = N[Abs[t], $MachinePrecision]
t\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[t]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[t$95$s_, x_, l$95$m_, t$95$m_] := Block[{t$95$2 = N[(N[Sqrt[2.0], $MachinePrecision] * t$95$m), $MachinePrecision]}, N[(t$95$s * If[LessEqual[N[(l$95$m * l$95$m), $MachinePrecision], 1e+276], N[(t$95$2 / N[(t$95$m * N[Sqrt[N[(N[(x * 2.0 + 2.0), $MachinePrecision] / N[(x + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(t$95$2 / N[(l$95$m * N[Sqrt[N[(2.0 / x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]]
\begin{array}{l}
l_m = \left|\ell\right|
\\
t\_m = \left|t\right|
\\
t\_s = \mathsf{copysign}\left(1, t\right)
\\
\begin{array}{l}
t_2 := \sqrt{2} \cdot t\_m\\
t\_s \cdot \begin{array}{l}
\mathbf{if}\;l\_m \cdot l\_m \leq 10^{+276}:\\
\;\;\;\;\frac{t\_2}{t\_m \cdot \sqrt{\frac{\mathsf{fma}\left(x, 2, 2\right)}{x + -1}}}\\
\mathbf{else}:\\
\;\;\;\;\frac{t\_2}{l\_m \cdot \sqrt{\frac{2}{x}}}\\
\end{array}
\end{array}
\end{array}
if (*.f64 l l) < 1.0000000000000001e276Initial program 42.0%
Taylor expanded in l around 0
lower-*.f64N/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
lower-/.f64N/A
lower-+.f64N/A
sub-negN/A
metadata-evalN/A
lower-+.f6485.4
Applied rewrites85.4%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
Applied rewrites85.3%
Applied rewrites85.3%
if 1.0000000000000001e276 < (*.f64 l l) Initial program 0.6%
Applied rewrites0.7%
Taylor expanded in l around inf
lower-*.f64N/A
lower-sqrt.f64N/A
sub-negN/A
metadata-evalN/A
lower-+.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-+.f64N/A
lower-+.f64N/A
sub-negN/A
unpow2N/A
metadata-evalN/A
lower-fma.f643.0
Applied rewrites3.0%
Taylor expanded in x around inf
Applied rewrites56.5%
Final simplification79.1%
herbie shell --seed 2024227
(FPCore (x l t)
:name "Toniolo and Linder, Equation (7)"
:precision binary64
(/ (* (sqrt 2.0) t) (sqrt (- (* (/ (+ x 1.0) (- x 1.0)) (+ (* l l) (* 2.0 (* t t)))) (* l l)))))