
(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 6 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 57.5%
associate-+l-73.7%
sub-neg73.7%
log1p-define80.5%
neg-sub080.5%
associate-+l-80.5%
neg-sub080.5%
+-commutative80.5%
unsub-neg80.5%
*-rgt-identity80.5%
distribute-lft-out--80.6%
expm1-define98.0%
Simplified98.0%
Final simplification98.0%
(FPCore (x y z t) :precision binary64 (if (<= y -1.9e+204) (/ (log1p (* y z)) (- t)) (- x (* y (/ (expm1 z) t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (y <= -1.9e+204) {
tmp = log1p((y * z)) / -t;
} else {
tmp = x - (y * (expm1(z) / t));
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (y <= -1.9e+204) {
tmp = Math.log1p((y * z)) / -t;
} else {
tmp = x - (y * (Math.expm1(z) / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if y <= -1.9e+204: tmp = math.log1p((y * z)) / -t else: tmp = x - (y * (math.expm1(z) / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if (y <= -1.9e+204) tmp = Float64(log1p(Float64(y * z)) / Float64(-t)); else tmp = Float64(x - Float64(y * Float64(expm1(z) / t))); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[y, -1.9e+204], N[(N[Log[1 + N[(y * z), $MachinePrecision]], $MachinePrecision] / (-t)), $MachinePrecision], N[(x - N[(y * N[(N[(Exp[z] - 1), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.9 \cdot 10^{+204}:\\
\;\;\;\;\frac{\mathsf{log1p}\left(y \cdot z\right)}{-t}\\
\mathbf{else}:\\
\;\;\;\;x - y \cdot \frac{\mathsf{expm1}\left(z\right)}{t}\\
\end{array}
\end{array}
if y < -1.8999999999999999e204Initial program 40.4%
associate-+l-56.3%
sub-neg56.3%
log1p-define56.3%
neg-sub056.3%
associate-+l-56.3%
neg-sub056.3%
+-commutative56.3%
unsub-neg56.3%
*-rgt-identity56.3%
distribute-lft-out--56.3%
expm1-define99.8%
Simplified99.8%
Taylor expanded in z around 0 59.8%
Taylor expanded in z around 0 63.3%
Taylor expanded in x around 0 43.2%
associate-*r/43.2%
log1p-define45.3%
*-commutative45.3%
neg-mul-145.3%
distribute-neg-frac45.3%
distribute-neg-frac245.3%
*-commutative45.3%
Simplified45.3%
if -1.8999999999999999e204 < y Initial program 59.0%
associate-+l-75.2%
sub-neg75.2%
log1p-define82.6%
neg-sub082.6%
associate-+l-82.6%
neg-sub082.6%
+-commutative82.6%
unsub-neg82.6%
*-rgt-identity82.6%
distribute-lft-out--82.6%
expm1-define97.9%
Simplified97.9%
Taylor expanded in y around 0 79.5%
associate-/l*79.5%
expm1-define92.5%
Simplified92.5%
Final simplification88.8%
(FPCore (x y z t) :precision binary64 (if (<= z -9e+78) (- x (* y (/ (expm1 z) t))) (- x (/ (log1p (* y z)) t))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -9e+78) {
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 <= -9e+78) {
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 <= -9e+78: 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 <= -9e+78) tmp = Float64(x - Float64(y * Float64(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, -9e+78], N[(x - N[(y * N[(N[(Exp[z] - 1), $MachinePrecision] / t), $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 -9 \cdot 10^{+78}:\\
\;\;\;\;x - y \cdot \frac{\mathsf{expm1}\left(z\right)}{t}\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\mathsf{log1p}\left(y \cdot z\right)}{t}\\
\end{array}
\end{array}
if z < -8.9999999999999999e78Initial program 71.8%
associate-+l-71.8%
sub-neg71.8%
log1p-define100.0%
neg-sub0100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
unsub-neg100.0%
*-rgt-identity100.0%
distribute-lft-out--100.0%
expm1-define100.0%
Simplified100.0%
Taylor expanded in y around 0 87.3%
associate-/l*87.2%
expm1-define87.2%
Simplified87.2%
if -8.9999999999999999e78 < z Initial program 53.3%
associate-+l-74.3%
sub-neg74.3%
log1p-define74.7%
neg-sub074.7%
associate-+l-74.7%
neg-sub074.7%
+-commutative74.7%
unsub-neg74.7%
*-rgt-identity74.7%
distribute-lft-out--74.7%
expm1-define97.5%
Simplified97.5%
Taylor expanded in z around 0 92.1%
Taylor expanded in z around 0 95.0%
Final simplification93.2%
(FPCore (x y z t) :precision binary64 (if (<= z -9e+78) (- x (/ (* y (expm1 z)) t)) (- x (/ (log1p (* y z)) t))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -9e+78) {
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 <= -9e+78) {
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 <= -9e+78: 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 <= -9e+78) 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, -9e+78], 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 -9 \cdot 10^{+78}:\\
\;\;\;\;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 < -8.9999999999999999e78Initial program 71.8%
associate-+l-71.8%
sub-neg71.8%
log1p-define100.0%
neg-sub0100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
unsub-neg100.0%
*-rgt-identity100.0%
distribute-lft-out--100.0%
expm1-define100.0%
Simplified100.0%
Taylor expanded in y around 0 87.3%
expm1-define87.3%
Simplified87.3%
if -8.9999999999999999e78 < z Initial program 53.3%
associate-+l-74.3%
sub-neg74.3%
log1p-define74.7%
neg-sub074.7%
associate-+l-74.7%
neg-sub074.7%
+-commutative74.7%
unsub-neg74.7%
*-rgt-identity74.7%
distribute-lft-out--74.7%
expm1-define97.5%
Simplified97.5%
Taylor expanded in z around 0 92.1%
Taylor expanded in z around 0 95.0%
Final simplification93.2%
(FPCore (x y z t) :precision binary64 (if (<= z -5.2e-29) x (- x (* y (/ z t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -5.2e-29) {
tmp = x;
} else {
tmp = x - (y * (z / 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) :: tmp
if (z <= (-5.2d-29)) then
tmp = x
else
tmp = x - (y * (z / t))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -5.2e-29) {
tmp = x;
} else {
tmp = x - (y * (z / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -5.2e-29: tmp = x else: tmp = x - (y * (z / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -5.2e-29) tmp = x; else tmp = Float64(x - Float64(y * Float64(z / t))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (z <= -5.2e-29) tmp = x; else tmp = x - (y * (z / t)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[z, -5.2e-29], x, N[(x - N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -5.2 \cdot 10^{-29}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - y \cdot \frac{z}{t}\\
\end{array}
\end{array}
if z < -5.2000000000000004e-29Initial program 77.0%
associate-+l-78.1%
sub-neg78.1%
log1p-define98.1%
neg-sub098.1%
associate-+l-98.1%
neg-sub098.1%
+-commutative98.1%
unsub-neg98.1%
*-rgt-identity98.1%
distribute-lft-out--98.2%
expm1-define100.0%
Simplified100.0%
Taylor expanded in x around inf 65.3%
if -5.2000000000000004e-29 < z Initial program 47.9%
associate-+l-71.5%
sub-neg71.5%
log1p-define71.8%
neg-sub071.8%
associate-+l-71.8%
neg-sub071.8%
+-commutative71.8%
unsub-neg71.8%
*-rgt-identity71.8%
distribute-lft-out--71.8%
expm1-define97.1%
Simplified97.1%
Taylor expanded in z around 0 89.8%
associate-/l*91.0%
Simplified91.0%
Final simplification82.5%
(FPCore (x y z t) :precision binary64 x)
double code(double x, double y, double z, double t) {
return x;
}
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
end function
public static double code(double x, double y, double z, double t) {
return x;
}
def code(x, y, z, t): return x
function code(x, y, z, t) return x end
function tmp = code(x, y, z, t) tmp = x; end
code[x_, y_, z_, t_] := x
\begin{array}{l}
\\
x
\end{array}
Initial program 57.5%
associate-+l-73.7%
sub-neg73.7%
log1p-define80.5%
neg-sub080.5%
associate-+l-80.5%
neg-sub080.5%
+-commutative80.5%
unsub-neg80.5%
*-rgt-identity80.5%
distribute-lft-out--80.6%
expm1-define98.0%
Simplified98.0%
Taylor expanded in x around inf 69.8%
Final simplification69.8%
(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 2024071
(FPCore (x y z t)
:name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"
:precision binary64
:alt
(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)))