
(FPCore (x) :precision binary64 (exp (- (- 1.0 (* x x)))))
double code(double x) {
return exp(-(1.0 - (x * x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = exp(-(1.0d0 - (x * x)))
end function
public static double code(double x) {
return Math.exp(-(1.0 - (x * x)));
}
def code(x): return math.exp(-(1.0 - (x * x)))
function code(x) return exp(Float64(-Float64(1.0 - Float64(x * x)))) end
function tmp = code(x) tmp = exp(-(1.0 - (x * x))); end
code[x_] := N[Exp[(-N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision])], $MachinePrecision]
\begin{array}{l}
\\
e^{-\left(1 - x \cdot x\right)}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (exp (- (- 1.0 (* x x)))))
double code(double x) {
return exp(-(1.0 - (x * x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = exp(-(1.0d0 - (x * x)))
end function
public static double code(double x) {
return Math.exp(-(1.0 - (x * x)));
}
def code(x): return math.exp(-(1.0 - (x * x)))
function code(x) return exp(Float64(-Float64(1.0 - Float64(x * x)))) end
function tmp = code(x) tmp = exp(-(1.0 - (x * x))); end
code[x_] := N[Exp[(-N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision])], $MachinePrecision]
\begin{array}{l}
\\
e^{-\left(1 - x \cdot x\right)}
\end{array}
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (let* ((t_0 (exp (- x_m)))) (/ (- -1.0) (* (E) (pow (* t_0 t_0) (* 0.5 x_m))))))
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
t_0 := e^{-x\_m}\\
\frac{--1}{\mathsf{E}\left(\right) \cdot {\left(t\_0 \cdot t\_0\right)}^{\left(0.5 \cdot x\_m\right)}}
\end{array}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
lift-/.f64N/A
div-invN/A
lift-pow.f64N/A
lift-neg.f64N/A
pow-negN/A
frac-2negN/A
metadata-evalN/A
frac-timesN/A
metadata-evalN/A
lower-/.f64N/A
lower-*.f64N/A
lower-pow.f64N/A
lift-pow.f64N/A
unpow-1N/A
lift-exp.f64N/A
rec-expN/A
lift-neg.f64N/A
lower-exp.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
lift-pow.f64N/A
sqr-powN/A
pow-prod-downN/A
lower-pow.f64N/A
lower-*.f64N/A
div-invN/A
metadata-evalN/A
lower-*.f64100.0
Applied rewrites100.0%
Final simplification100.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ (- -1.0) (* (pow (exp (- x_m)) x_m) (E))))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{--1}{{\left(e^{-x\_m}\right)}^{x\_m} \cdot \mathsf{E}\left(\right)}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
lift-/.f64N/A
div-invN/A
lift-pow.f64N/A
lift-neg.f64N/A
pow-negN/A
frac-2negN/A
metadata-evalN/A
frac-timesN/A
metadata-evalN/A
lower-/.f64N/A
lower-*.f64N/A
lower-pow.f64N/A
lift-pow.f64N/A
unpow-1N/A
lift-exp.f64N/A
rec-expN/A
lift-neg.f64N/A
lower-exp.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Final simplification100.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ (pow (exp (- x_m)) (- x_m)) (E)))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{{\left(e^{-x\_m}\right)}^{\left(-x\_m\right)}}{\mathsf{E}\left(\right)}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
lift-pow.f64N/A
unpow-1N/A
lift-exp.f64N/A
rec-expN/A
lift-neg.f64N/A
lower-exp.f64100.0
Applied rewrites100.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ (pow (exp x_m) x_m) (E)))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{{\left(e^{x\_m}\right)}^{x\_m}}{\mathsf{E}\left(\right)}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (if (<= (* x_m x_m) 0.0002) (/ 1.0 (/ (E) (fma x_m x_m 1.0))) (exp (* x_m x_m))))
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
\mathbf{if}\;x\_m \cdot x\_m \leq 0.0002:\\
\;\;\;\;\frac{1}{\frac{\mathsf{E}\left(\right)}{\mathsf{fma}\left(x\_m, x\_m, 1\right)}}\\
\mathbf{else}:\\
\;\;\;\;e^{x\_m \cdot x\_m}\\
\end{array}
\end{array}
if (*.f64 x x) < 2.0000000000000001e-4Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6499.7
Applied rewrites99.7%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6499.7
Applied rewrites99.7%
if 2.0000000000000001e-4 < (*.f64 x x) Initial program 99.9%
Taylor expanded in x around 0
Applied rewrites3.1%
Taylor expanded in x around inf
unpow2N/A
lower-*.f6499.3
Applied rewrites99.3%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (exp (fma x_m x_m -1.0)))
x_m = fabs(x);
double code(double x_m) {
return exp(fma(x_m, x_m, -1.0));
}
x_m = abs(x) function code(x_m) return exp(fma(x_m, x_m, -1.0)) end
x_m = N[Abs[x], $MachinePrecision] code[x$95$m_] := N[Exp[N[(x$95$m * x$95$m + -1.0), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|
\\
e^{\mathsf{fma}\left(x\_m, x\_m, -1\right)}
\end{array}
Initial program 100.0%
lift-neg.f64N/A
neg-sub0N/A
lift--.f64N/A
associate--r-N/A
metadata-evalN/A
+-commutativeN/A
lift-*.f64N/A
lower-fma.f64100.0
Applied rewrites100.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (if (<= (* x_m x_m) 5e+293) (/ (/ (- 1.0 (* (* x_m x_m) (* x_m x_m))) (- 1.0 (* x_m x_m))) (E)) (/ (* x_m x_m) (E))))
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
\mathbf{if}\;x\_m \cdot x\_m \leq 5 \cdot 10^{+293}:\\
\;\;\;\;\frac{\frac{1 - \left(x\_m \cdot x\_m\right) \cdot \left(x\_m \cdot x\_m\right)}{1 - x\_m \cdot x\_m}}{\mathsf{E}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{x\_m \cdot x\_m}{\mathsf{E}\left(\right)}\\
\end{array}
\end{array}
if (*.f64 x x) < 5.00000000000000033e293Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6471.2
Applied rewrites71.2%
Applied rewrites84.1%
if 5.00000000000000033e293 < (*.f64 x x) Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f64100.0
Applied rewrites100.0%
Taylor expanded in x around inf
Applied rewrites100.0%
Final simplification87.8%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ 1.0 (/ (E) (fma x_m x_m 1.0))))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{1}{\frac{\mathsf{E}\left(\right)}{\mathsf{fma}\left(x\_m, x\_m, 1\right)}}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6478.0
Applied rewrites78.0%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6478.0
Applied rewrites78.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (if (<= (* x_m x_m) 1.0) (/ 1.0 (E)) (/ (* x_m x_m) (E))))
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
\mathbf{if}\;x\_m \cdot x\_m \leq 1:\\
\;\;\;\;\frac{1}{\mathsf{E}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{x\_m \cdot x\_m}{\mathsf{E}\left(\right)}\\
\end{array}
\end{array}
if (*.f64 x x) < 1Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
Applied rewrites99.2%
if 1 < (*.f64 x x) Initial program 99.9%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
/-rgt-identityN/A
clear-numN/A
lift-pow.f64N/A
pow-flipN/A
pow-flipN/A
exp-to-powN/A
lift-exp.f64N/A
rem-log-expN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
rem-log-expN/A
lift-exp.f64N/A
neg-logN/A
exp-to-powN/A
lower-pow.f64N/A
inv-powN/A
lower-pow.f64N/A
lower-neg.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6453.0
Applied rewrites53.0%
Taylor expanded in x around inf
Applied rewrites53.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ (fma x_m x_m 1.0) (E)))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{\mathsf{fma}\left(x\_m, x\_m, 1\right)}{\mathsf{E}\left(\right)}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6478.0
Applied rewrites78.0%
x_m = (fabs.f64 x) (FPCore (x_m) :precision binary64 (/ 1.0 (E)))
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{1}{\mathsf{E}\left(\right)}
\end{array}
Initial program 100.0%
lift-exp.f64N/A
lift-neg.f64N/A
exp-negN/A
lift--.f64N/A
exp-diffN/A
clear-numN/A
lower-/.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
exp-1-eN/A
lower-E.f64100.0
Applied rewrites100.0%
Taylor expanded in x around 0
Applied rewrites54.6%
herbie shell --seed 2024332
(FPCore (x)
:name "exp neg sub"
:precision binary64
(exp (- (- 1.0 (* x x)))))