
(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 64.3%
sub-neg64.3%
associate-+l+78.0%
cancel-sign-sub78.0%
log1p-define82.0%
cancel-sign-sub82.0%
+-commutative82.0%
unsub-neg82.0%
*-rgt-identity82.0%
distribute-lft-out--82.0%
expm1-define97.7%
Simplified97.7%
Final simplification97.7%
(FPCore (x y z t) :precision binary64 (+ x (/ (/ -1.0 t) (+ 0.5 (/ 1.0 (* y (expm1 z)))))))
double code(double x, double y, double z, double t) {
return x + ((-1.0 / t) / (0.5 + (1.0 / (y * expm1(z)))));
}
public static double code(double x, double y, double z, double t) {
return x + ((-1.0 / t) / (0.5 + (1.0 / (y * Math.expm1(z)))));
}
def code(x, y, z, t): return x + ((-1.0 / t) / (0.5 + (1.0 / (y * math.expm1(z)))))
function code(x, y, z, t) return Float64(x + Float64(Float64(-1.0 / t) / Float64(0.5 + Float64(1.0 / Float64(y * expm1(z)))))) end
code[x_, y_, z_, t_] := N[(x + N[(N[(-1.0 / t), $MachinePrecision] / N[(0.5 + N[(1.0 / N[(y * N[(Exp[z] - 1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{\frac{-1}{t}}{0.5 + \frac{1}{y \cdot \mathsf{expm1}\left(z\right)}}
\end{array}
Initial program 64.3%
sub-neg64.3%
associate-+l+78.0%
cancel-sign-sub78.0%
log1p-define82.0%
cancel-sign-sub82.0%
+-commutative82.0%
unsub-neg82.0%
*-rgt-identity82.0%
distribute-lft-out--82.0%
expm1-define97.7%
Simplified97.7%
clear-num97.7%
inv-pow97.7%
Applied egg-rr97.7%
clear-num97.7%
associate-/r/97.6%
Applied egg-rr97.6%
unpow-197.6%
*-commutative97.6%
associate-/r*97.6%
Applied egg-rr97.6%
Taylor expanded in y around 0 78.2%
expm1-define88.8%
Simplified88.8%
Final simplification88.8%
(FPCore (x y z t) :precision binary64 (if (<= y -7.2e+142) x (- x (* y (/ (expm1 z) t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (y <= -7.2e+142) {
tmp = x;
} 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 <= -7.2e+142) {
tmp = x;
} else {
tmp = x - (y * (Math.expm1(z) / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if y <= -7.2e+142: tmp = x else: tmp = x - (y * (math.expm1(z) / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if (y <= -7.2e+142) tmp = x; else tmp = Float64(x - Float64(y * Float64(expm1(z) / t))); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[y, -7.2e+142], x, N[(x - N[(y * N[(N[(Exp[z] - 1), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -7.2 \cdot 10^{+142}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - y \cdot \frac{\mathsf{expm1}\left(z\right)}{t}\\
\end{array}
\end{array}
if y < -7.2000000000000003e142Initial program 63.8%
sub-neg63.8%
associate-+l+81.3%
cancel-sign-sub81.3%
log1p-define81.3%
cancel-sign-sub81.3%
+-commutative81.3%
unsub-neg81.3%
*-rgt-identity81.3%
distribute-lft-out--81.6%
expm1-define99.7%
Simplified99.7%
Taylor expanded in x around inf 59.0%
if -7.2000000000000003e142 < y Initial program 64.4%
sub-neg64.4%
associate-+l+77.5%
cancel-sign-sub77.5%
log1p-define82.1%
cancel-sign-sub82.1%
+-commutative82.1%
unsub-neg82.1%
*-rgt-identity82.1%
distribute-lft-out--82.1%
expm1-define97.5%
Simplified97.5%
Taylor expanded in y around 0 80.0%
expm1-define90.4%
associate-/l*91.1%
Simplified91.1%
Final simplification87.6%
(FPCore (x y z t) :precision binary64 (if (<= z -6.2e-31) x (+ x (* y (* z (/ -1.0 t))))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -6.2e-31) {
tmp = x;
} else {
tmp = x + (y * (z * (-1.0 / 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 <= (-6.2d-31)) then
tmp = x
else
tmp = x + (y * (z * ((-1.0d0) / t)))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -6.2e-31) {
tmp = x;
} else {
tmp = x + (y * (z * (-1.0 / t)));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -6.2e-31: tmp = x else: tmp = x + (y * (z * (-1.0 / t))) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -6.2e-31) tmp = x; else tmp = Float64(x + Float64(y * Float64(z * Float64(-1.0 / t)))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (z <= -6.2e-31) tmp = x; else tmp = x + (y * (z * (-1.0 / t))); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[z, -6.2e-31], x, N[(x + N[(y * N[(z * N[(-1.0 / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -6.2 \cdot 10^{-31}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x + y \cdot \left(z \cdot \frac{-1}{t}\right)\\
\end{array}
\end{array}
if z < -6.19999999999999999e-31Initial program 85.4%
sub-neg85.4%
associate-+l+85.6%
cancel-sign-sub85.6%
log1p-define97.2%
cancel-sign-sub97.2%
+-commutative97.2%
unsub-neg97.2%
*-rgt-identity97.2%
distribute-lft-out--97.4%
expm1-define99.9%
Simplified99.9%
Taylor expanded in x around inf 72.3%
if -6.19999999999999999e-31 < z Initial program 54.2%
sub-neg54.2%
associate-+l+74.3%
cancel-sign-sub74.3%
log1p-define74.7%
cancel-sign-sub74.7%
+-commutative74.7%
unsub-neg74.7%
*-rgt-identity74.7%
distribute-lft-out--74.7%
expm1-define96.7%
Simplified96.7%
Taylor expanded in z around 0 87.8%
frac-2neg87.8%
div-inv87.7%
distribute-rgt-neg-in87.7%
neg-mul-187.7%
associate-/r*87.7%
metadata-eval87.7%
Applied egg-rr87.7%
associate-*l*88.7%
Simplified88.7%
frac-2neg88.7%
metadata-eval88.7%
div-inv88.7%
frac-2neg88.7%
clear-num88.3%
Applied egg-rr88.3%
associate-/r/88.7%
Simplified88.7%
Final simplification83.4%
(FPCore (x y z t) :precision binary64 (if (<= z -1.3e-31) x (- x (* y (/ z t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -1.3e-31) {
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 <= (-1.3d-31)) 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 <= -1.3e-31) {
tmp = x;
} else {
tmp = x - (y * (z / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -1.3e-31: tmp = x else: tmp = x - (y * (z / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -1.3e-31) 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 <= -1.3e-31) tmp = x; else tmp = x - (y * (z / t)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[z, -1.3e-31], x, N[(x - N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -1.3 \cdot 10^{-31}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - y \cdot \frac{z}{t}\\
\end{array}
\end{array}
if z < -1.29999999999999998e-31Initial program 85.4%
sub-neg85.4%
associate-+l+85.6%
cancel-sign-sub85.6%
log1p-define97.2%
cancel-sign-sub97.2%
+-commutative97.2%
unsub-neg97.2%
*-rgt-identity97.2%
distribute-lft-out--97.4%
expm1-define99.9%
Simplified99.9%
Taylor expanded in x around inf 72.3%
if -1.29999999999999998e-31 < z Initial program 54.2%
sub-neg54.2%
associate-+l+74.3%
cancel-sign-sub74.3%
log1p-define74.7%
cancel-sign-sub74.7%
+-commutative74.7%
unsub-neg74.7%
*-rgt-identity74.7%
distribute-lft-out--74.7%
expm1-define96.7%
Simplified96.7%
Taylor expanded in z around 0 87.8%
associate-/l*88.7%
Simplified88.7%
Final simplification83.4%
(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 64.3%
sub-neg64.3%
associate-+l+78.0%
cancel-sign-sub78.0%
log1p-define82.0%
cancel-sign-sub82.0%
+-commutative82.0%
unsub-neg82.0%
*-rgt-identity82.0%
distribute-lft-out--82.0%
expm1-define97.7%
Simplified97.7%
Taylor expanded in x around inf 73.6%
Final simplification73.6%
(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 2024046
(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)))