exp neg sub

Percentage Accurate: 100.0% → 100.0%
Time: 4.8s
Alternatives: 5
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ e^{-\left(1 - x \cdot x\right)} \end{array} \]
(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:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 5 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ e^{-\left(1 - x \cdot x\right)} \end{array} \]
(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}

Alternative 1: 100.0% accurate, 0.3× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} t_0 := e^{-1 + x\_m}\\ {t\_0}^{\left(x\_m + 0.5\right)} \cdot \sqrt{t\_0} \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (let* ((t_0 (exp (+ -1.0 x_m)))) (* (pow t_0 (+ x_m 0.5)) (sqrt t_0))))
x_m = fabs(x);
double code(double x_m) {
	double t_0 = exp((-1.0 + x_m));
	return pow(t_0, (x_m + 0.5)) * sqrt(t_0);
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: t_0
    t_0 = exp(((-1.0d0) + x_m))
    code = (t_0 ** (x_m + 0.5d0)) * sqrt(t_0)
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double t_0 = Math.exp((-1.0 + x_m));
	return Math.pow(t_0, (x_m + 0.5)) * Math.sqrt(t_0);
}
x_m = math.fabs(x)
def code(x_m):
	t_0 = math.exp((-1.0 + x_m))
	return math.pow(t_0, (x_m + 0.5)) * math.sqrt(t_0)
x_m = abs(x)
function code(x_m)
	t_0 = exp(Float64(-1.0 + x_m))
	return Float64((t_0 ^ Float64(x_m + 0.5)) * sqrt(t_0))
end
x_m = abs(x);
function tmp = code(x_m)
	t_0 = exp((-1.0 + x_m));
	tmp = (t_0 ^ (x_m + 0.5)) * sqrt(t_0);
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := Block[{t$95$0 = N[Exp[N[(-1.0 + x$95$m), $MachinePrecision]], $MachinePrecision]}, N[(N[Power[t$95$0, N[(x$95$m + 0.5), $MachinePrecision]], $MachinePrecision] * N[Sqrt[t$95$0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
t_0 := e^{-1 + x\_m}\\
{t\_0}^{\left(x\_m + 0.5\right)} \cdot \sqrt{t\_0}
\end{array}
\end{array}
Derivation
  1. Initial program 100.0%

    \[e^{-\left(1 - x \cdot x\right)} \]
  2. Step-by-step derivation
    1. neg-sub0100.0%

      \[\leadsto e^{\color{blue}{0 - \left(1 - x \cdot x\right)}} \]
    2. sqr-neg100.0%

      \[\leadsto e^{0 - \left(1 - \color{blue}{\left(-x\right) \cdot \left(-x\right)}\right)} \]
    3. associate--r-100.0%

      \[\leadsto e^{\color{blue}{\left(0 - 1\right) + \left(-x\right) \cdot \left(-x\right)}} \]
    4. metadata-eval100.0%

      \[\leadsto e^{\color{blue}{-1} + \left(-x\right) \cdot \left(-x\right)} \]
    5. +-commutative100.0%

      \[\leadsto e^{\color{blue}{\left(-x\right) \cdot \left(-x\right) + -1}} \]
    6. sqr-neg100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} + -1} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{e^{x \cdot x + -1}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-un-lft-identity100.0%

      \[\leadsto e^{\color{blue}{1 \cdot \left(x \cdot x + -1\right)}} \]
    2. exp-prod99.9%

      \[\leadsto \color{blue}{{\left(e^{1}\right)}^{\left(x \cdot x + -1\right)}} \]
    3. expm1-log1p-u99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(\mathsf{expm1}\left(\mathsf{log1p}\left(x \cdot x + -1\right)\right)\right)}} \]
    4. expm1-undefine99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)} - 1\right)}} \]
    5. pow-sub99.9%

      \[\leadsto \color{blue}{\frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)}\right)}}{{\left(e^{1}\right)}^{1}}} \]
    6. fma-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(x, x, -1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    7. metadata-eval99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\mathsf{fma}\left(x, x, \color{blue}{-1}\right)\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    8. fma-neg99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{x \cdot x - 1}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    9. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{{\left(x \cdot x\right)}^{1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    10. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{e^{\log \left(x \cdot x\right) \cdot 1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    11. expm1-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{expm1}\left(\log \left(x \cdot x\right) \cdot 1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    12. log1p-expm1-u99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\color{blue}{\log \left(x \cdot x\right) \cdot 1}}\right)}}{{\left(e^{1}\right)}^{1}} \]
    13. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left({\left(x \cdot x\right)}^{1}\right)}}}{{\left(e^{1}\right)}^{1}} \]
    14. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    15. exp-prod99.9%

      \[\leadsto \frac{\color{blue}{e^{1 \cdot \left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    16. *-un-lft-identity99.9%

      \[\leadsto \frac{e^{\color{blue}{x \cdot x}}}{{\left(e^{1}\right)}^{1}} \]
    17. pow299.9%

      \[\leadsto \frac{e^{\color{blue}{{x}^{2}}}}{{\left(e^{1}\right)}^{1}} \]
    18. pow199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    19. exp-1-e99.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e}} \]
  6. Applied egg-rr99.9%

    \[\leadsto \color{blue}{\frac{e^{{x}^{2}}}{e}} \]
  7. Step-by-step derivation
    1. e-exp-199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    2. div-exp100.0%

      \[\leadsto \color{blue}{e^{{x}^{2} - 1}} \]
    3. unpow2100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} - 1} \]
    4. difference-of-sqr-199.9%

      \[\leadsto e^{\color{blue}{\left(x + 1\right) \cdot \left(x - 1\right)}} \]
    5. sub-neg99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \color{blue}{\left(x + \left(-1\right)\right)}} \]
    6. metadata-eval99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \left(x + \color{blue}{-1}\right)} \]
    7. add-log-exp99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \color{blue}{\log \left(e^{x + -1}\right)}} \]
    8. log-pow99.9%

      \[\leadsto e^{\color{blue}{\log \left({\left(e^{x + -1}\right)}^{\left(x + 1\right)}\right)}} \]
    9. add-exp-log100.0%

      \[\leadsto \color{blue}{{\left(e^{x + -1}\right)}^{\left(x + 1\right)}} \]
    10. pow-plus76.9%

      \[\leadsto \color{blue}{{\left(e^{x + -1}\right)}^{x} \cdot e^{x + -1}} \]
    11. add-sqr-sqrt76.9%

      \[\leadsto {\left(e^{x + -1}\right)}^{x} \cdot \color{blue}{\left(\sqrt{e^{x + -1}} \cdot \sqrt{e^{x + -1}}\right)} \]
    12. associate-*r*76.9%

      \[\leadsto \color{blue}{\left({\left(e^{x + -1}\right)}^{x} \cdot \sqrt{e^{x + -1}}\right) \cdot \sqrt{e^{x + -1}}} \]
    13. +-commutative76.9%

      \[\leadsto \left({\left(e^{\color{blue}{-1 + x}}\right)}^{x} \cdot \sqrt{e^{x + -1}}\right) \cdot \sqrt{e^{x + -1}} \]
    14. +-commutative76.9%

      \[\leadsto \left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{\color{blue}{-1 + x}}}\right) \cdot \sqrt{e^{x + -1}} \]
    15. +-commutative76.9%

      \[\leadsto \left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}\right) \cdot \sqrt{e^{\color{blue}{-1 + x}}} \]
  8. Applied egg-rr76.9%

    \[\leadsto \color{blue}{\left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}\right) \cdot \sqrt{e^{-1 + x}}} \]
  9. Step-by-step derivation
    1. add-log-exp76.5%

      \[\leadsto \color{blue}{\log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)} \cdot \sqrt{e^{-1 + x}} \]
    2. *-un-lft-identity76.5%

      \[\leadsto \log \color{blue}{\left(1 \cdot e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)} \cdot \sqrt{e^{-1 + x}} \]
    3. log-prod76.5%

      \[\leadsto \color{blue}{\left(\log 1 + \log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)\right)} \cdot \sqrt{e^{-1 + x}} \]
    4. metadata-eval76.5%

      \[\leadsto \left(\color{blue}{0} + \log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)\right) \cdot \sqrt{e^{-1 + x}} \]
    5. add-log-exp76.9%

      \[\leadsto \left(0 + \color{blue}{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right) \cdot \sqrt{e^{-1 + x}} \]
    6. pow1/276.9%

      \[\leadsto \left(0 + {\left(e^{-1 + x}\right)}^{x} \cdot \color{blue}{{\left(e^{-1 + x}\right)}^{0.5}}\right) \cdot \sqrt{e^{-1 + x}} \]
    7. pow-prod-up76.9%

      \[\leadsto \left(0 + \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}}\right) \cdot \sqrt{e^{-1 + x}} \]
  10. Applied egg-rr76.9%

    \[\leadsto \color{blue}{\left(0 + {\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}\right)} \cdot \sqrt{e^{-1 + x}} \]
  11. Step-by-step derivation
    1. +-lft-identity76.9%

      \[\leadsto \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}} \cdot \sqrt{e^{-1 + x}} \]
  12. Simplified76.9%

    \[\leadsto \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}} \cdot \sqrt{e^{-1 + x}} \]
  13. Add Preprocessing

Alternative 2: 100.0% accurate, 0.3× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ {\left(e^{-1 + x\_m}\right)}^{\left(x\_m + 0.5\right)} \cdot e^{\left(-1 + x\_m\right) \cdot 0.5} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (* (pow (exp (+ -1.0 x_m)) (+ x_m 0.5)) (exp (* (+ -1.0 x_m) 0.5))))
x_m = fabs(x);
double code(double x_m) {
	return pow(exp((-1.0 + x_m)), (x_m + 0.5)) * exp(((-1.0 + x_m) * 0.5));
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = (exp(((-1.0d0) + x_m)) ** (x_m + 0.5d0)) * exp((((-1.0d0) + x_m) * 0.5d0))
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return Math.pow(Math.exp((-1.0 + x_m)), (x_m + 0.5)) * Math.exp(((-1.0 + x_m) * 0.5));
}
x_m = math.fabs(x)
def code(x_m):
	return math.pow(math.exp((-1.0 + x_m)), (x_m + 0.5)) * math.exp(((-1.0 + x_m) * 0.5))
x_m = abs(x)
function code(x_m)
	return Float64((exp(Float64(-1.0 + x_m)) ^ Float64(x_m + 0.5)) * exp(Float64(Float64(-1.0 + x_m) * 0.5)))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = (exp((-1.0 + x_m)) ^ (x_m + 0.5)) * exp(((-1.0 + x_m) * 0.5));
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(N[Power[N[Exp[N[(-1.0 + x$95$m), $MachinePrecision]], $MachinePrecision], N[(x$95$m + 0.5), $MachinePrecision]], $MachinePrecision] * N[Exp[N[(N[(-1.0 + x$95$m), $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
{\left(e^{-1 + x\_m}\right)}^{\left(x\_m + 0.5\right)} \cdot e^{\left(-1 + x\_m\right) \cdot 0.5}
\end{array}
Derivation
  1. Initial program 100.0%

    \[e^{-\left(1 - x \cdot x\right)} \]
  2. Step-by-step derivation
    1. neg-sub0100.0%

      \[\leadsto e^{\color{blue}{0 - \left(1 - x \cdot x\right)}} \]
    2. sqr-neg100.0%

      \[\leadsto e^{0 - \left(1 - \color{blue}{\left(-x\right) \cdot \left(-x\right)}\right)} \]
    3. associate--r-100.0%

      \[\leadsto e^{\color{blue}{\left(0 - 1\right) + \left(-x\right) \cdot \left(-x\right)}} \]
    4. metadata-eval100.0%

      \[\leadsto e^{\color{blue}{-1} + \left(-x\right) \cdot \left(-x\right)} \]
    5. +-commutative100.0%

      \[\leadsto e^{\color{blue}{\left(-x\right) \cdot \left(-x\right) + -1}} \]
    6. sqr-neg100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} + -1} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{e^{x \cdot x + -1}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-un-lft-identity100.0%

      \[\leadsto e^{\color{blue}{1 \cdot \left(x \cdot x + -1\right)}} \]
    2. exp-prod99.9%

      \[\leadsto \color{blue}{{\left(e^{1}\right)}^{\left(x \cdot x + -1\right)}} \]
    3. expm1-log1p-u99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(\mathsf{expm1}\left(\mathsf{log1p}\left(x \cdot x + -1\right)\right)\right)}} \]
    4. expm1-undefine99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)} - 1\right)}} \]
    5. pow-sub99.9%

      \[\leadsto \color{blue}{\frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)}\right)}}{{\left(e^{1}\right)}^{1}}} \]
    6. fma-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(x, x, -1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    7. metadata-eval99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\mathsf{fma}\left(x, x, \color{blue}{-1}\right)\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    8. fma-neg99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{x \cdot x - 1}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    9. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{{\left(x \cdot x\right)}^{1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    10. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{e^{\log \left(x \cdot x\right) \cdot 1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    11. expm1-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{expm1}\left(\log \left(x \cdot x\right) \cdot 1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    12. log1p-expm1-u99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\color{blue}{\log \left(x \cdot x\right) \cdot 1}}\right)}}{{\left(e^{1}\right)}^{1}} \]
    13. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left({\left(x \cdot x\right)}^{1}\right)}}}{{\left(e^{1}\right)}^{1}} \]
    14. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    15. exp-prod99.9%

      \[\leadsto \frac{\color{blue}{e^{1 \cdot \left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    16. *-un-lft-identity99.9%

      \[\leadsto \frac{e^{\color{blue}{x \cdot x}}}{{\left(e^{1}\right)}^{1}} \]
    17. pow299.9%

      \[\leadsto \frac{e^{\color{blue}{{x}^{2}}}}{{\left(e^{1}\right)}^{1}} \]
    18. pow199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    19. exp-1-e99.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e}} \]
  6. Applied egg-rr99.9%

    \[\leadsto \color{blue}{\frac{e^{{x}^{2}}}{e}} \]
  7. Step-by-step derivation
    1. e-exp-199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    2. div-exp100.0%

      \[\leadsto \color{blue}{e^{{x}^{2} - 1}} \]
    3. unpow2100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} - 1} \]
    4. difference-of-sqr-199.9%

      \[\leadsto e^{\color{blue}{\left(x + 1\right) \cdot \left(x - 1\right)}} \]
    5. sub-neg99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \color{blue}{\left(x + \left(-1\right)\right)}} \]
    6. metadata-eval99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \left(x + \color{blue}{-1}\right)} \]
    7. add-log-exp99.9%

      \[\leadsto e^{\left(x + 1\right) \cdot \color{blue}{\log \left(e^{x + -1}\right)}} \]
    8. log-pow99.9%

      \[\leadsto e^{\color{blue}{\log \left({\left(e^{x + -1}\right)}^{\left(x + 1\right)}\right)}} \]
    9. add-exp-log100.0%

      \[\leadsto \color{blue}{{\left(e^{x + -1}\right)}^{\left(x + 1\right)}} \]
    10. pow-plus76.9%

      \[\leadsto \color{blue}{{\left(e^{x + -1}\right)}^{x} \cdot e^{x + -1}} \]
    11. add-sqr-sqrt76.9%

      \[\leadsto {\left(e^{x + -1}\right)}^{x} \cdot \color{blue}{\left(\sqrt{e^{x + -1}} \cdot \sqrt{e^{x + -1}}\right)} \]
    12. associate-*r*76.9%

      \[\leadsto \color{blue}{\left({\left(e^{x + -1}\right)}^{x} \cdot \sqrt{e^{x + -1}}\right) \cdot \sqrt{e^{x + -1}}} \]
    13. +-commutative76.9%

      \[\leadsto \left({\left(e^{\color{blue}{-1 + x}}\right)}^{x} \cdot \sqrt{e^{x + -1}}\right) \cdot \sqrt{e^{x + -1}} \]
    14. +-commutative76.9%

      \[\leadsto \left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{\color{blue}{-1 + x}}}\right) \cdot \sqrt{e^{x + -1}} \]
    15. +-commutative76.9%

      \[\leadsto \left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}\right) \cdot \sqrt{e^{\color{blue}{-1 + x}}} \]
  8. Applied egg-rr76.9%

    \[\leadsto \color{blue}{\left({\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}\right) \cdot \sqrt{e^{-1 + x}}} \]
  9. Step-by-step derivation
    1. add-log-exp76.5%

      \[\leadsto \color{blue}{\log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)} \cdot \sqrt{e^{-1 + x}} \]
    2. *-un-lft-identity76.5%

      \[\leadsto \log \color{blue}{\left(1 \cdot e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)} \cdot \sqrt{e^{-1 + x}} \]
    3. log-prod76.5%

      \[\leadsto \color{blue}{\left(\log 1 + \log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)\right)} \cdot \sqrt{e^{-1 + x}} \]
    4. metadata-eval76.5%

      \[\leadsto \left(\color{blue}{0} + \log \left(e^{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right)\right) \cdot \sqrt{e^{-1 + x}} \]
    5. add-log-exp76.9%

      \[\leadsto \left(0 + \color{blue}{{\left(e^{-1 + x}\right)}^{x} \cdot \sqrt{e^{-1 + x}}}\right) \cdot \sqrt{e^{-1 + x}} \]
    6. pow1/276.9%

      \[\leadsto \left(0 + {\left(e^{-1 + x}\right)}^{x} \cdot \color{blue}{{\left(e^{-1 + x}\right)}^{0.5}}\right) \cdot \sqrt{e^{-1 + x}} \]
    7. pow-prod-up76.9%

      \[\leadsto \left(0 + \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}}\right) \cdot \sqrt{e^{-1 + x}} \]
  10. Applied egg-rr76.9%

    \[\leadsto \color{blue}{\left(0 + {\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}\right)} \cdot \sqrt{e^{-1 + x}} \]
  11. Step-by-step derivation
    1. +-lft-identity76.9%

      \[\leadsto \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}} \cdot \sqrt{e^{-1 + x}} \]
  12. Simplified76.9%

    \[\leadsto \color{blue}{{\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)}} \cdot \sqrt{e^{-1 + x}} \]
  13. Step-by-step derivation
    1. pow1/276.9%

      \[\leadsto {\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)} \cdot \color{blue}{{\left(e^{-1 + x}\right)}^{0.5}} \]
    2. pow-exp76.9%

      \[\leadsto {\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)} \cdot \color{blue}{e^{\left(-1 + x\right) \cdot 0.5}} \]
  14. Applied egg-rr76.9%

    \[\leadsto {\left(e^{-1 + x}\right)}^{\left(x + 0.5\right)} \cdot \color{blue}{e^{\left(-1 + x\right) \cdot 0.5}} \]
  15. Add Preprocessing

Alternative 3: 100.0% accurate, 0.5× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \frac{{\left(e^{x\_m}\right)}^{x\_m}}{e} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (/ (pow (exp x_m) x_m) E))
x_m = fabs(x);
double code(double x_m) {
	return pow(exp(x_m), x_m) / ((double) M_E);
}
x_m = Math.abs(x);
public static double code(double x_m) {
	return Math.pow(Math.exp(x_m), x_m) / Math.E;
}
x_m = math.fabs(x)
def code(x_m):
	return math.pow(math.exp(x_m), x_m) / math.e
x_m = abs(x)
function code(x_m)
	return Float64((exp(x_m) ^ x_m) / exp(1))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = (exp(x_m) ^ x_m) / 2.71828182845904523536;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(N[Power[N[Exp[x$95$m], $MachinePrecision], x$95$m], $MachinePrecision] / E), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
\frac{{\left(e^{x\_m}\right)}^{x\_m}}{e}
\end{array}
Derivation
  1. Initial program 100.0%

    \[e^{-\left(1 - x \cdot x\right)} \]
  2. Step-by-step derivation
    1. neg-sub0100.0%

      \[\leadsto e^{\color{blue}{0 - \left(1 - x \cdot x\right)}} \]
    2. sqr-neg100.0%

      \[\leadsto e^{0 - \left(1 - \color{blue}{\left(-x\right) \cdot \left(-x\right)}\right)} \]
    3. associate--r-100.0%

      \[\leadsto e^{\color{blue}{\left(0 - 1\right) + \left(-x\right) \cdot \left(-x\right)}} \]
    4. metadata-eval100.0%

      \[\leadsto e^{\color{blue}{-1} + \left(-x\right) \cdot \left(-x\right)} \]
    5. +-commutative100.0%

      \[\leadsto e^{\color{blue}{\left(-x\right) \cdot \left(-x\right) + -1}} \]
    6. sqr-neg100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} + -1} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{e^{x \cdot x + -1}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-un-lft-identity100.0%

      \[\leadsto e^{\color{blue}{1 \cdot \left(x \cdot x + -1\right)}} \]
    2. exp-prod99.9%

      \[\leadsto \color{blue}{{\left(e^{1}\right)}^{\left(x \cdot x + -1\right)}} \]
    3. expm1-log1p-u99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(\mathsf{expm1}\left(\mathsf{log1p}\left(x \cdot x + -1\right)\right)\right)}} \]
    4. expm1-undefine99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)} - 1\right)}} \]
    5. pow-sub99.9%

      \[\leadsto \color{blue}{\frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)}\right)}}{{\left(e^{1}\right)}^{1}}} \]
    6. fma-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(x, x, -1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    7. metadata-eval99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\mathsf{fma}\left(x, x, \color{blue}{-1}\right)\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    8. fma-neg99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{x \cdot x - 1}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    9. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{{\left(x \cdot x\right)}^{1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    10. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{e^{\log \left(x \cdot x\right) \cdot 1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    11. expm1-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{expm1}\left(\log \left(x \cdot x\right) \cdot 1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    12. log1p-expm1-u99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\color{blue}{\log \left(x \cdot x\right) \cdot 1}}\right)}}{{\left(e^{1}\right)}^{1}} \]
    13. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left({\left(x \cdot x\right)}^{1}\right)}}}{{\left(e^{1}\right)}^{1}} \]
    14. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    15. exp-prod99.9%

      \[\leadsto \frac{\color{blue}{e^{1 \cdot \left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    16. *-un-lft-identity99.9%

      \[\leadsto \frac{e^{\color{blue}{x \cdot x}}}{{\left(e^{1}\right)}^{1}} \]
    17. pow299.9%

      \[\leadsto \frac{e^{\color{blue}{{x}^{2}}}}{{\left(e^{1}\right)}^{1}} \]
    18. pow199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    19. exp-1-e99.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e}} \]
  6. Applied egg-rr99.9%

    \[\leadsto \color{blue}{\frac{e^{{x}^{2}}}{e}} \]
  7. Step-by-step derivation
    1. unpow299.9%

      \[\leadsto \frac{e^{\color{blue}{x \cdot x}}}{e} \]
    2. exp-prod100.0%

      \[\leadsto \frac{\color{blue}{{\left(e^{x}\right)}^{x}}}{e} \]
  8. Applied egg-rr100.0%

    \[\leadsto \frac{\color{blue}{{\left(e^{x}\right)}^{x}}}{e} \]
  9. Add Preprocessing

Alternative 4: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ e^{-1 + x\_m \cdot x\_m} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (exp (+ -1.0 (* x_m x_m))))
x_m = fabs(x);
double code(double x_m) {
	return exp((-1.0 + (x_m * x_m)));
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = exp(((-1.0d0) + (x_m * x_m)))
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return Math.exp((-1.0 + (x_m * x_m)));
}
x_m = math.fabs(x)
def code(x_m):
	return math.exp((-1.0 + (x_m * x_m)))
x_m = abs(x)
function code(x_m)
	return exp(Float64(-1.0 + Float64(x_m * x_m)))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = exp((-1.0 + (x_m * x_m)));
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[Exp[N[(-1.0 + N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
e^{-1 + x\_m \cdot x\_m}
\end{array}
Derivation
  1. Initial program 100.0%

    \[e^{-\left(1 - x \cdot x\right)} \]
  2. Step-by-step derivation
    1. neg-sub0100.0%

      \[\leadsto e^{\color{blue}{0 - \left(1 - x \cdot x\right)}} \]
    2. sqr-neg100.0%

      \[\leadsto e^{0 - \left(1 - \color{blue}{\left(-x\right) \cdot \left(-x\right)}\right)} \]
    3. associate--r-100.0%

      \[\leadsto e^{\color{blue}{\left(0 - 1\right) + \left(-x\right) \cdot \left(-x\right)}} \]
    4. metadata-eval100.0%

      \[\leadsto e^{\color{blue}{-1} + \left(-x\right) \cdot \left(-x\right)} \]
    5. +-commutative100.0%

      \[\leadsto e^{\color{blue}{\left(-x\right) \cdot \left(-x\right) + -1}} \]
    6. sqr-neg100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} + -1} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{e^{x \cdot x + -1}} \]
  4. Add Preprocessing
  5. Final simplification100.0%

    \[\leadsto e^{-1 + x \cdot x} \]
  6. Add Preprocessing

Alternative 5: 50.7% accurate, 35.3× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \frac{1}{e} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (/ 1.0 E))
x_m = fabs(x);
double code(double x_m) {
	return 1.0 / ((double) M_E);
}
x_m = Math.abs(x);
public static double code(double x_m) {
	return 1.0 / Math.E;
}
x_m = math.fabs(x)
def code(x_m):
	return 1.0 / math.e
x_m = abs(x)
function code(x_m)
	return Float64(1.0 / exp(1))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = 1.0 / 2.71828182845904523536;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(1.0 / E), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
\frac{1}{e}
\end{array}
Derivation
  1. Initial program 100.0%

    \[e^{-\left(1 - x \cdot x\right)} \]
  2. Step-by-step derivation
    1. neg-sub0100.0%

      \[\leadsto e^{\color{blue}{0 - \left(1 - x \cdot x\right)}} \]
    2. sqr-neg100.0%

      \[\leadsto e^{0 - \left(1 - \color{blue}{\left(-x\right) \cdot \left(-x\right)}\right)} \]
    3. associate--r-100.0%

      \[\leadsto e^{\color{blue}{\left(0 - 1\right) + \left(-x\right) \cdot \left(-x\right)}} \]
    4. metadata-eval100.0%

      \[\leadsto e^{\color{blue}{-1} + \left(-x\right) \cdot \left(-x\right)} \]
    5. +-commutative100.0%

      \[\leadsto e^{\color{blue}{\left(-x\right) \cdot \left(-x\right) + -1}} \]
    6. sqr-neg100.0%

      \[\leadsto e^{\color{blue}{x \cdot x} + -1} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{e^{x \cdot x + -1}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-un-lft-identity100.0%

      \[\leadsto e^{\color{blue}{1 \cdot \left(x \cdot x + -1\right)}} \]
    2. exp-prod99.9%

      \[\leadsto \color{blue}{{\left(e^{1}\right)}^{\left(x \cdot x + -1\right)}} \]
    3. expm1-log1p-u99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(\mathsf{expm1}\left(\mathsf{log1p}\left(x \cdot x + -1\right)\right)\right)}} \]
    4. expm1-undefine99.9%

      \[\leadsto {\left(e^{1}\right)}^{\color{blue}{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)} - 1\right)}} \]
    5. pow-sub99.9%

      \[\leadsto \color{blue}{\frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(x \cdot x + -1\right)}\right)}}{{\left(e^{1}\right)}^{1}}} \]
    6. fma-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(x, x, -1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    7. metadata-eval99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\mathsf{fma}\left(x, x, \color{blue}{-1}\right)\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    8. fma-neg99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{x \cdot x - 1}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    9. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{{\left(x \cdot x\right)}^{1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    10. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{e^{\log \left(x \cdot x\right) \cdot 1}} - 1\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    11. expm1-define99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\mathsf{log1p}\left(\color{blue}{\mathsf{expm1}\left(\log \left(x \cdot x\right) \cdot 1\right)}\right)}\right)}}{{\left(e^{1}\right)}^{1}} \]
    12. log1p-expm1-u99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\left(e^{\color{blue}{\log \left(x \cdot x\right) \cdot 1}}\right)}}{{\left(e^{1}\right)}^{1}} \]
    13. pow-to-exp99.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left({\left(x \cdot x\right)}^{1}\right)}}}{{\left(e^{1}\right)}^{1}} \]
    14. pow199.9%

      \[\leadsto \frac{{\left(e^{1}\right)}^{\color{blue}{\left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    15. exp-prod99.9%

      \[\leadsto \frac{\color{blue}{e^{1 \cdot \left(x \cdot x\right)}}}{{\left(e^{1}\right)}^{1}} \]
    16. *-un-lft-identity99.9%

      \[\leadsto \frac{e^{\color{blue}{x \cdot x}}}{{\left(e^{1}\right)}^{1}} \]
    17. pow299.9%

      \[\leadsto \frac{e^{\color{blue}{{x}^{2}}}}{{\left(e^{1}\right)}^{1}} \]
    18. pow199.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e^{1}}} \]
    19. exp-1-e99.9%

      \[\leadsto \frac{e^{{x}^{2}}}{\color{blue}{e}} \]
  6. Applied egg-rr99.9%

    \[\leadsto \color{blue}{\frac{e^{{x}^{2}}}{e}} \]
  7. Taylor expanded in x around 0 54.5%

    \[\leadsto \frac{\color{blue}{1}}{e} \]
  8. Add Preprocessing

Reproduce

?
herbie shell --seed 2024128 
(FPCore (x)
  :name "exp neg sub"
  :precision binary64
  (exp (- (- 1.0 (* x x)))))