
(FPCore (x) :precision binary64 (/ (exp x) (- (exp x) 1.0)))
double code(double x) {
return exp(x) / (exp(x) - 1.0);
}
real(8) function code(x)
real(8), intent (in) :: x
code = exp(x) / (exp(x) - 1.0d0)
end function
public static double code(double x) {
return Math.exp(x) / (Math.exp(x) - 1.0);
}
def code(x): return math.exp(x) / (math.exp(x) - 1.0)
function code(x) return Float64(exp(x) / Float64(exp(x) - 1.0)) end
function tmp = code(x) tmp = exp(x) / (exp(x) - 1.0); end
code[x_] := N[(N[Exp[x], $MachinePrecision] / N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{e^{x}}{e^{x} - 1}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (/ (exp x) (- (exp x) 1.0)))
double code(double x) {
return exp(x) / (exp(x) - 1.0);
}
real(8) function code(x)
real(8), intent (in) :: x
code = exp(x) / (exp(x) - 1.0d0)
end function
public static double code(double x) {
return Math.exp(x) / (Math.exp(x) - 1.0);
}
def code(x): return math.exp(x) / (math.exp(x) - 1.0)
function code(x) return Float64(exp(x) / Float64(exp(x) - 1.0)) end
function tmp = code(x) tmp = exp(x) / (exp(x) - 1.0); end
code[x_] := N[(N[Exp[x], $MachinePrecision] / N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{e^{x}}{e^{x} - 1}
\end{array}
(FPCore (x) :precision binary64 (/ -1.0 (expm1 (- x))))
double code(double x) {
return -1.0 / expm1(-x);
}
public static double code(double x) {
return -1.0 / Math.expm1(-x);
}
def code(x): return -1.0 / math.expm1(-x)
function code(x) return Float64(-1.0 / expm1(Float64(-x))) end
code[x_] := N[(-1.0 / N[(Exp[(-x)] - 1), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{\mathsf{expm1}\left(-x\right)}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Final simplification100.0%
(FPCore (x)
:precision binary64
(/
-1.0
(*
x
(+
-1.0
(* x (+ 0.5 (* x (- (* x 0.041666666666666664) 0.16666666666666666))))))))
double code(double x) {
return -1.0 / (x * (-1.0 + (x * (0.5 + (x * ((x * 0.041666666666666664) - 0.16666666666666666))))));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-1.0d0) / (x * ((-1.0d0) + (x * (0.5d0 + (x * ((x * 0.041666666666666664d0) - 0.16666666666666666d0))))))
end function
public static double code(double x) {
return -1.0 / (x * (-1.0 + (x * (0.5 + (x * ((x * 0.041666666666666664) - 0.16666666666666666))))));
}
def code(x): return -1.0 / (x * (-1.0 + (x * (0.5 + (x * ((x * 0.041666666666666664) - 0.16666666666666666))))))
function code(x) return Float64(-1.0 / Float64(x * Float64(-1.0 + Float64(x * Float64(0.5 + Float64(x * Float64(Float64(x * 0.041666666666666664) - 0.16666666666666666))))))) end
function tmp = code(x) tmp = -1.0 / (x * (-1.0 + (x * (0.5 + (x * ((x * 0.041666666666666664) - 0.16666666666666666)))))); end
code[x_] := N[(-1.0 / N[(x * N[(-1.0 + N[(x * N[(0.5 + N[(x * N[(N[(x * 0.041666666666666664), $MachinePrecision] - 0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{x \cdot \left(-1 + x \cdot \left(0.5 + x \cdot \left(x \cdot 0.041666666666666664 - 0.16666666666666666\right)\right)\right)}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 92.5%
Final simplification92.5%
(FPCore (x) :precision binary64 (/ -1.0 (* x (+ -1.0 (* x (+ 0.5 (* x -0.16666666666666666)))))))
double code(double x) {
return -1.0 / (x * (-1.0 + (x * (0.5 + (x * -0.16666666666666666)))));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-1.0d0) / (x * ((-1.0d0) + (x * (0.5d0 + (x * (-0.16666666666666666d0))))))
end function
public static double code(double x) {
return -1.0 / (x * (-1.0 + (x * (0.5 + (x * -0.16666666666666666)))));
}
def code(x): return -1.0 / (x * (-1.0 + (x * (0.5 + (x * -0.16666666666666666)))))
function code(x) return Float64(-1.0 / Float64(x * Float64(-1.0 + Float64(x * Float64(0.5 + Float64(x * -0.16666666666666666)))))) end
function tmp = code(x) tmp = -1.0 / (x * (-1.0 + (x * (0.5 + (x * -0.16666666666666666))))); end
code[x_] := N[(-1.0 / N[(x * N[(-1.0 + N[(x * N[(0.5 + N[(x * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{x \cdot \left(-1 + x \cdot \left(0.5 + x \cdot -0.16666666666666666\right)\right)}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 90.8%
Final simplification90.8%
(FPCore (x) :precision binary64 (/ -1.0 (* x (+ -1.0 (* x 0.5)))))
double code(double x) {
return -1.0 / (x * (-1.0 + (x * 0.5)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-1.0d0) / (x * ((-1.0d0) + (x * 0.5d0)))
end function
public static double code(double x) {
return -1.0 / (x * (-1.0 + (x * 0.5)));
}
def code(x): return -1.0 / (x * (-1.0 + (x * 0.5)))
function code(x) return Float64(-1.0 / Float64(x * Float64(-1.0 + Float64(x * 0.5)))) end
function tmp = code(x) tmp = -1.0 / (x * (-1.0 + (x * 0.5))); end
code[x_] := N[(-1.0 / N[(x * N[(-1.0 + N[(x * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{x \cdot \left(-1 + x \cdot 0.5\right)}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 87.1%
Final simplification87.1%
(FPCore (x) :precision binary64 (- 0.5 (/ -1.0 x)))
double code(double x) {
return 0.5 - (-1.0 / x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.5d0 - ((-1.0d0) / x)
end function
public static double code(double x) {
return 0.5 - (-1.0 / x);
}
def code(x): return 0.5 - (-1.0 / x)
function code(x) return Float64(0.5 - Float64(-1.0 / x)) end
function tmp = code(x) tmp = 0.5 - (-1.0 / x); end
code[x_] := N[(0.5 - N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.5 - \frac{-1}{x}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 87.1%
sub-neg87.1%
metadata-eval87.1%
distribute-rgt-in87.1%
*-commutative87.1%
Applied egg-rr87.1%
Taylor expanded in x around 0 71.6%
+-commutative71.6%
*-commutative71.6%
metadata-eval71.6%
sub-neg71.6%
div-sub71.6%
*-commutative71.6%
associate-*l/71.6%
metadata-eval71.6%
associate-*r/71.6%
associate-*l*71.6%
lft-mult-inverse71.6%
metadata-eval71.6%
Simplified71.6%
Final simplification71.6%
(FPCore (x) :precision binary64 (/ 1.0 x))
double code(double x) {
return 1.0 / x;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0 / x
end function
public static double code(double x) {
return 1.0 / x;
}
def code(x): return 1.0 / x
function code(x) return Float64(1.0 / x) end
function tmp = code(x) tmp = 1.0 / x; end
code[x_] := N[(1.0 / x), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{x}
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 71.6%
Final simplification71.6%
(FPCore (x) :precision binary64 -0.5)
double code(double x) {
return -0.5;
}
real(8) function code(x)
real(8), intent (in) :: x
code = -0.5d0
end function
public static double code(double x) {
return -0.5;
}
def code(x): return -0.5
function code(x) return -0.5 end
function tmp = code(x) tmp = -0.5; end
code[x_] := -0.5
\begin{array}{l}
\\
-0.5
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 71.6%
*-commutative71.6%
Simplified71.6%
frac-2neg71.6%
mul-1-neg71.6%
div-inv71.6%
+-commutative71.6%
fma-define71.6%
add-sqr-sqrt28.5%
sqrt-unprod30.4%
mul-1-neg30.4%
mul-1-neg30.4%
sqr-neg30.4%
sqrt-unprod0.3%
add-sqr-sqrt1.5%
Applied egg-rr1.5%
associate-*r/1.5%
*-rgt-identity1.5%
distribute-neg-frac1.5%
*-lft-identity1.5%
associate-*l/1.5%
fma-undefine1.5%
distribute-lft-in1.5%
*-commutative1.5%
associate-*l*1.5%
*-commutative1.5%
associate-*l*1.5%
lft-mult-inverse1.5%
metadata-eval1.5%
*-rgt-identity1.5%
mul-1-neg1.5%
distribute-lft-in1.5%
metadata-eval1.5%
neg-mul-11.5%
distribute-neg-frac1.5%
metadata-eval1.5%
Simplified1.5%
Taylor expanded in x around inf 3.0%
Final simplification3.0%
(FPCore (x) :precision binary64 0.5)
double code(double x) {
return 0.5;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.5d0
end function
public static double code(double x) {
return 0.5;
}
def code(x): return 0.5
function code(x) return 0.5 end
function tmp = code(x) tmp = 0.5; end
code[x_] := 0.5
\begin{array}{l}
\\
0.5
\end{array}
Initial program 33.3%
sub-neg33.3%
+-commutative33.3%
rgt-mult-inverse6.8%
exp-neg6.8%
distribute-rgt-neg-out6.8%
*-rgt-identity6.8%
distribute-lft-in6.7%
neg-sub06.7%
associate-+l-6.7%
neg-sub06.1%
associate-/r*6.1%
*-rgt-identity6.1%
associate-*r/6.1%
rgt-mult-inverse32.7%
distribute-frac-neg232.7%
distribute-neg-frac32.7%
metadata-eval32.7%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around 0 71.6%
*-commutative71.6%
Simplified71.6%
Taylor expanded in x around inf 3.7%
Final simplification3.7%
(FPCore (x) :precision binary64 (/ (- 1.0) (expm1 (- x))))
double code(double x) {
return -1.0 / expm1(-x);
}
public static double code(double x) {
return -1.0 / Math.expm1(-x);
}
def code(x): return -1.0 / math.expm1(-x)
function code(x) return Float64(Float64(-1.0) / expm1(Float64(-x))) end
code[x_] := N[((-1.0) / N[(Exp[(-x)] - 1), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{\mathsf{expm1}\left(-x\right)}
\end{array}
herbie shell --seed 2024075
(FPCore (x)
:name "expq2 (section 3.11)"
:precision binary64
:pre (> 710.0 x)
:alt
(/ (- 1.0) (expm1 (- x)))
(/ (exp x) (- (exp x) 1.0)))