
(FPCore (x y z t) :precision binary64 (- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))
double code(double x, double y, double z, double t) {
return x - (log(((1.0 - y) + (y * exp(z)))) / t);
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = x - (log(((1.0d0 - y) + (y * exp(z)))) / t)
end function
public static double code(double x, double y, double z, double t) {
return x - (Math.log(((1.0 - y) + (y * Math.exp(z)))) / t);
}
def code(x, y, z, t): return x - (math.log(((1.0 - y) + (y * math.exp(z)))) / t)
function code(x, y, z, t) return Float64(x - Float64(log(Float64(Float64(1.0 - y) + Float64(y * exp(z)))) / t)) end
function tmp = code(x, y, z, t) tmp = x - (log(((1.0 - y) + (y * exp(z)))) / t); end
code[x_, y_, z_, t_] := N[(x - N[(N[Log[N[(N[(1.0 - y), $MachinePrecision] + N[(y * N[Exp[z], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z t) :precision binary64 (- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))
double code(double x, double y, double z, double t) {
return x - (log(((1.0 - y) + (y * exp(z)))) / t);
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = x - (log(((1.0d0 - y) + (y * exp(z)))) / t)
end function
public static double code(double x, double y, double z, double t) {
return x - (Math.log(((1.0 - y) + (y * Math.exp(z)))) / t);
}
def code(x, y, z, t): return x - (math.log(((1.0 - y) + (y * math.exp(z)))) / t)
function code(x, y, z, t) return Float64(x - Float64(log(Float64(Float64(1.0 - y) + Float64(y * exp(z)))) / t)) end
function tmp = code(x, y, z, t) tmp = x - (log(((1.0 - y) + (y * exp(z)))) / t); end
code[x_, y_, z_, t_] := N[(x - N[(N[Log[N[(N[(1.0 - y), $MachinePrecision] + N[(y * N[Exp[z], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}
\end{array}
(FPCore (x y z t) :precision binary64 (- x (/ (log1p (* y (expm1 z))) t)))
double code(double x, double y, double z, double t) {
return x - (log1p((y * expm1(z))) / t);
}
public static double code(double x, double y, double z, double t) {
return x - (Math.log1p((y * Math.expm1(z))) / t);
}
def code(x, y, z, t): return x - (math.log1p((y * math.expm1(z))) / t)
function code(x, y, z, t) return Float64(x - Float64(log1p(Float64(y * expm1(z))) / t)) end
code[x_, y_, z_, t_] := N[(x - N[(N[Log[1 + N[(y * N[(Exp[z] - 1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - \frac{\mathsf{log1p}\left(y \cdot \mathsf{expm1}\left(z\right)\right)}{t}
\end{array}
Initial program 62.2%
associate-+l-73.7%
sub-neg73.7%
log1p-def79.0%
neg-sub079.0%
associate-+l-79.0%
neg-sub079.0%
neg-mul-179.0%
*-commutative79.0%
distribute-rgt-out79.0%
+-commutative79.0%
metadata-eval79.0%
sub-neg79.0%
expm1-def97.6%
Simplified97.6%
Final simplification97.6%
(FPCore (x y z t) :precision binary64 (if (<= z -4e-81) (- x (/ (expm1 z) (/ t y))) (+ x (* y (- (* z (* (/ z t) -0.5)) (/ z t))))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -4e-81) {
tmp = x - (expm1(z) / (t / y));
} else {
tmp = x + (y * ((z * ((z / t) * -0.5)) - (z / t)));
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -4e-81) {
tmp = x - (Math.expm1(z) / (t / y));
} else {
tmp = x + (y * ((z * ((z / t) * -0.5)) - (z / t)));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -4e-81: tmp = x - (math.expm1(z) / (t / y)) else: tmp = x + (y * ((z * ((z / t) * -0.5)) - (z / t))) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -4e-81) tmp = Float64(x - Float64(expm1(z) / Float64(t / y))); else tmp = Float64(x + Float64(y * Float64(Float64(z * Float64(Float64(z / t) * -0.5)) - Float64(z / t)))); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[z, -4e-81], N[(x - N[(N[(Exp[z] - 1), $MachinePrecision] / N[(t / y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x + N[(y * N[(N[(z * N[(N[(z / t), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision] - N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -4 \cdot 10^{-81}:\\
\;\;\;\;x - \frac{\mathsf{expm1}\left(z\right)}{\frac{t}{y}}\\
\mathbf{else}:\\
\;\;\;\;x + y \cdot \left(z \cdot \left(\frac{z}{t} \cdot -0.5\right) - \frac{z}{t}\right)\\
\end{array}
\end{array}
if z < -3.9999999999999998e-81Initial program 79.4%
associate-+l-80.5%
sub-neg80.5%
log1p-def91.7%
neg-sub091.7%
associate-+l-91.7%
neg-sub091.7%
neg-mul-191.7%
*-commutative91.7%
distribute-rgt-out91.8%
+-commutative91.8%
metadata-eval91.8%
sub-neg91.8%
expm1-def99.1%
Simplified99.1%
Taylor expanded in y around 0 73.3%
expm1-def76.7%
associate-/l*77.5%
Simplified77.5%
if -3.9999999999999998e-81 < z Initial program 50.6%
associate-+l-69.2%
sub-neg69.2%
log1p-def70.5%
neg-sub070.5%
associate-+l-70.5%
neg-sub070.5%
neg-mul-170.5%
*-commutative70.5%
distribute-rgt-out70.5%
+-commutative70.5%
metadata-eval70.5%
sub-neg70.5%
expm1-def96.6%
Simplified96.6%
Taylor expanded in y around 0 70.2%
expm1-def86.5%
associate-/l*84.4%
Simplified84.4%
Taylor expanded in z around 0 86.8%
*-commutative86.8%
associate-/l*86.8%
unpow286.8%
Simplified86.8%
Taylor expanded in y around -inf 88.6%
mul-1-neg88.6%
distribute-rgt-neg-in88.6%
mul-1-neg88.6%
unsub-neg88.6%
*-commutative88.6%
unpow288.6%
associate-*r/88.6%
associate-*l*88.6%
Simplified88.6%
Final simplification84.1%
(FPCore (x y z t) :precision binary64 (if (<= z -1.05e+22) (- x (/ (expm1 z) (/ t y))) (- x (/ (log1p (* y z)) t))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -1.05e+22) {
tmp = x - (expm1(z) / (t / y));
} else {
tmp = x - (log1p((y * z)) / t);
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -1.05e+22) {
tmp = x - (Math.expm1(z) / (t / y));
} else {
tmp = x - (Math.log1p((y * z)) / t);
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -1.05e+22: tmp = x - (math.expm1(z) / (t / y)) else: tmp = x - (math.log1p((y * z)) / t) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -1.05e+22) tmp = Float64(x - Float64(expm1(z) / Float64(t / y))); else tmp = Float64(x - Float64(log1p(Float64(y * z)) / t)); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[z, -1.05e+22], N[(x - N[(N[(Exp[z] - 1), $MachinePrecision] / N[(t / y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[1 + N[(y * z), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -1.05 \cdot 10^{+22}:\\
\;\;\;\;x - \frac{\mathsf{expm1}\left(z\right)}{\frac{t}{y}}\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\mathsf{log1p}\left(y \cdot z\right)}{t}\\
\end{array}
\end{array}
if z < -1.0499999999999999e22Initial program 85.4%
associate-+l-85.4%
sub-neg85.4%
log1p-def100.0%
neg-sub0100.0%
associate-+l-100.0%
neg-sub0100.0%
neg-mul-1100.0%
*-commutative100.0%
distribute-rgt-out100.0%
+-commutative100.0%
metadata-eval100.0%
sub-neg100.0%
expm1-def100.0%
Simplified100.0%
Taylor expanded in y around 0 78.9%
expm1-def78.9%
associate-/l*78.8%
Simplified78.8%
if -1.0499999999999999e22 < z Initial program 53.1%
remove-double-neg53.1%
sub0-neg53.1%
sub0-neg53.1%
remove-double-neg53.1%
sub-neg53.1%
associate-+l+69.2%
log1p-def70.8%
+-commutative70.8%
unsub-neg70.8%
Simplified70.8%
Taylor expanded in z around 0 70.5%
Taylor expanded in y around 0 95.9%
*-commutative95.9%
Simplified95.9%
Final simplification91.1%
(FPCore (x y z t) :precision binary64 (if (<= z -1.05e+22) (- x (/ (* y (expm1 z)) t)) (- x (/ (log1p (* y z)) t))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -1.05e+22) {
tmp = x - ((y * expm1(z)) / t);
} else {
tmp = x - (log1p((y * z)) / t);
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -1.05e+22) {
tmp = x - ((y * Math.expm1(z)) / t);
} else {
tmp = x - (Math.log1p((y * z)) / t);
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -1.05e+22: tmp = x - ((y * math.expm1(z)) / t) else: tmp = x - (math.log1p((y * z)) / t) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -1.05e+22) tmp = Float64(x - Float64(Float64(y * expm1(z)) / t)); else tmp = Float64(x - Float64(log1p(Float64(y * z)) / t)); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[z, -1.05e+22], N[(x - N[(N[(y * N[(Exp[z] - 1), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[1 + N[(y * z), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -1.05 \cdot 10^{+22}:\\
\;\;\;\;x - \frac{y \cdot \mathsf{expm1}\left(z\right)}{t}\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\mathsf{log1p}\left(y \cdot z\right)}{t}\\
\end{array}
\end{array}
if z < -1.0499999999999999e22Initial program 85.4%
associate-+l-85.4%
sub-neg85.4%
log1p-def100.0%
neg-sub0100.0%
associate-+l-100.0%
neg-sub0100.0%
neg-mul-1100.0%
*-commutative100.0%
distribute-rgt-out100.0%
+-commutative100.0%
metadata-eval100.0%
sub-neg100.0%
expm1-def100.0%
Simplified100.0%
Taylor expanded in y around 0 78.9%
expm1-def78.9%
*-commutative78.9%
Simplified78.9%
if -1.0499999999999999e22 < z Initial program 53.1%
remove-double-neg53.1%
sub0-neg53.1%
sub0-neg53.1%
remove-double-neg53.1%
sub-neg53.1%
associate-+l+69.2%
log1p-def70.8%
+-commutative70.8%
unsub-neg70.8%
Simplified70.8%
Taylor expanded in z around 0 70.5%
Taylor expanded in y around 0 95.9%
*-commutative95.9%
Simplified95.9%
Final simplification91.1%
(FPCore (x y z t) :precision binary64 (- x (* z (/ y t))))
double code(double x, double y, double z, double t) {
return x - (z * (y / t));
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = x - (z * (y / t))
end function
public static double code(double x, double y, double z, double t) {
return x - (z * (y / t));
}
def code(x, y, z, t): return x - (z * (y / t))
function code(x, y, z, t) return Float64(x - Float64(z * Float64(y / t))) end
function tmp = code(x, y, z, t) tmp = x - (z * (y / t)); end
code[x_, y_, z_, t_] := N[(x - N[(z * N[(y / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - z \cdot \frac{y}{t}
\end{array}
Initial program 62.2%
associate-+l-73.7%
sub-neg73.7%
log1p-def79.0%
neg-sub079.0%
associate-+l-79.0%
neg-sub079.0%
neg-mul-179.0%
*-commutative79.0%
distribute-rgt-out79.0%
+-commutative79.0%
metadata-eval79.0%
sub-neg79.0%
expm1-def97.6%
Simplified97.6%
Taylor expanded in z around 0 72.5%
associate-/l*73.9%
associate-/r/72.4%
Simplified72.4%
Final simplification72.4%
(FPCore (x y z t) :precision binary64 (- x (* y (/ z t))))
double code(double x, double y, double z, double t) {
return x - (y * (z / t));
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = x - (y * (z / t))
end function
public static double code(double x, double y, double z, double t) {
return x - (y * (z / t));
}
def code(x, y, z, t): return x - (y * (z / t))
function code(x, y, z, t) return Float64(x - Float64(y * Float64(z / t))) end
function tmp = code(x, y, z, t) tmp = x - (y * (z / t)); end
code[x_, y_, z_, t_] := N[(x - N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - y \cdot \frac{z}{t}
\end{array}
Initial program 62.2%
associate-+l-73.7%
sub-neg73.7%
log1p-def79.0%
neg-sub079.0%
associate-+l-79.0%
neg-sub079.0%
neg-mul-179.0%
*-commutative79.0%
distribute-rgt-out79.0%
+-commutative79.0%
metadata-eval79.0%
sub-neg79.0%
expm1-def97.6%
Simplified97.6%
Taylor expanded in z around 0 72.5%
associate-/l*73.9%
associate-/r/72.4%
Simplified72.4%
expm1-log1p-u67.6%
expm1-udef62.4%
*-commutative62.4%
clear-num62.4%
un-div-inv62.4%
Applied egg-rr62.4%
expm1-def67.6%
expm1-log1p72.4%
associate-/r/73.9%
Simplified73.9%
Final simplification73.9%
(FPCore (x y z t) :precision binary64 (- x (/ y (/ t z))))
double code(double x, double y, double z, double t) {
return x - (y / (t / z));
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = x - (y / (t / z))
end function
public static double code(double x, double y, double z, double t) {
return x - (y / (t / z));
}
def code(x, y, z, t): return x - (y / (t / z))
function code(x, y, z, t) return Float64(x - Float64(y / Float64(t / z))) end
function tmp = code(x, y, z, t) tmp = x - (y / (t / z)); end
code[x_, y_, z_, t_] := N[(x - N[(y / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - \frac{y}{\frac{t}{z}}
\end{array}
Initial program 62.2%
associate-+l-73.7%
sub-neg73.7%
log1p-def79.0%
neg-sub079.0%
associate-+l-79.0%
neg-sub079.0%
neg-mul-179.0%
*-commutative79.0%
distribute-rgt-out79.0%
+-commutative79.0%
metadata-eval79.0%
sub-neg79.0%
expm1-def97.6%
Simplified97.6%
Taylor expanded in z around 0 72.5%
associate-/l*73.9%
Simplified73.9%
Final simplification73.9%
(FPCore (x y z t)
:precision binary64
(let* ((t_1 (/ (- 0.5) (* y t))))
(if (< z -2.8874623088207947e+119)
(- (- x (/ t_1 (* z z))) (* t_1 (/ (/ 2.0 z) (* z z))))
(- x (/ (log (+ 1.0 (* z y))) t)))))
double code(double x, double y, double z, double t) {
double t_1 = -0.5 / (y * t);
double tmp;
if (z < -2.8874623088207947e+119) {
tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)));
} else {
tmp = x - (log((1.0 + (z * y))) / t);
}
return tmp;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
real(8) :: t_1
real(8) :: tmp
t_1 = -0.5d0 / (y * t)
if (z < (-2.8874623088207947d+119)) then
tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0d0 / z) / (z * z)))
else
tmp = x - (log((1.0d0 + (z * y))) / t)
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double t_1 = -0.5 / (y * t);
double tmp;
if (z < -2.8874623088207947e+119) {
tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)));
} else {
tmp = x - (Math.log((1.0 + (z * y))) / t);
}
return tmp;
}
def code(x, y, z, t): t_1 = -0.5 / (y * t) tmp = 0 if z < -2.8874623088207947e+119: tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z))) else: tmp = x - (math.log((1.0 + (z * y))) / t) return tmp
function code(x, y, z, t) t_1 = Float64(Float64(-0.5) / Float64(y * t)) tmp = 0.0 if (z < -2.8874623088207947e+119) tmp = Float64(Float64(x - Float64(t_1 / Float64(z * z))) - Float64(t_1 * Float64(Float64(2.0 / z) / Float64(z * z)))); else tmp = Float64(x - Float64(log(Float64(1.0 + Float64(z * y))) / t)); end return tmp end
function tmp_2 = code(x, y, z, t) t_1 = -0.5 / (y * t); tmp = 0.0; if (z < -2.8874623088207947e+119) tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z))); else tmp = x - (log((1.0 + (z * y))) / t); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[((-0.5) / N[(y * t), $MachinePrecision]), $MachinePrecision]}, If[Less[z, -2.8874623088207947e+119], N[(N[(x - N[(t$95$1 / N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(t$95$1 * N[(N[(2.0 / z), $MachinePrecision] / N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[N[(1.0 + N[(z * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \frac{-0.5}{y \cdot t}\\
\mathbf{if}\;z < -2.8874623088207947 \cdot 10^{+119}:\\
\;\;\;\;\left(x - \frac{t_1}{z \cdot z}\right) - t_1 \cdot \frac{\frac{2}{z}}{z \cdot z}\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\log \left(1 + z \cdot y\right)}{t}\\
\end{array}
\end{array}
herbie shell --seed 2023196
(FPCore (x y z t)
:name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"
:precision binary64
:herbie-target
(if (< z -2.8874623088207947e+119) (- (- x (/ (/ (- 0.5) (* y t)) (* z z))) (* (/ (- 0.5) (* y t)) (/ (/ 2.0 z) (* z z)))) (- x (/ (log (+ 1.0 (* z y))) t)))
(- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))