
(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 59.5%
sub-neg59.5%
associate-+l+76.7%
cancel-sign-sub76.7%
log1p-def82.1%
cancel-sign-sub82.1%
+-commutative82.1%
unsub-neg82.1%
*-rgt-identity82.1%
distribute-lft-out--82.1%
expm1-def98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (x y z t) :precision binary64 (if (<= y -2.3e+177) x (+ x (/ -1.0 (/ 1.0 (* y (/ (expm1 z) t)))))))
double code(double x, double y, double z, double t) {
double tmp;
if (y <= -2.3e+177) {
tmp = x;
} else {
tmp = x + (-1.0 / (1.0 / (y * (expm1(z) / t))));
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (y <= -2.3e+177) {
tmp = x;
} else {
tmp = x + (-1.0 / (1.0 / (y * (Math.expm1(z) / t))));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if y <= -2.3e+177: tmp = x else: tmp = x + (-1.0 / (1.0 / (y * (math.expm1(z) / t)))) return tmp
function code(x, y, z, t) tmp = 0.0 if (y <= -2.3e+177) tmp = x; else tmp = Float64(x + Float64(-1.0 / Float64(1.0 / Float64(y * Float64(expm1(z) / t))))); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[y, -2.3e+177], x, N[(x + N[(-1.0 / N[(1.0 / N[(y * N[(N[(Exp[z] - 1), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -2.3 \cdot 10^{+177}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x + \frac{-1}{\frac{1}{y \cdot \frac{\mathsf{expm1}\left(z\right)}{t}}}\\
\end{array}
\end{array}
if y < -2.2999999999999999e177Initial program 50.6%
sub-neg50.6%
associate-+l+77.5%
cancel-sign-sub77.5%
log1p-def77.5%
cancel-sign-sub77.5%
+-commutative77.5%
unsub-neg77.5%
*-rgt-identity77.5%
distribute-lft-out--77.5%
expm1-def100.0%
Simplified100.0%
Taylor expanded in x around inf 56.8%
if -2.2999999999999999e177 < y Initial program 60.6%
sub-neg60.6%
associate-+l+76.6%
cancel-sign-sub76.6%
log1p-def82.7%
cancel-sign-sub82.7%
+-commutative82.7%
unsub-neg82.7%
*-rgt-identity82.7%
distribute-lft-out--82.7%
expm1-def98.3%
Simplified98.3%
Taylor expanded in y around 0 78.5%
clear-num78.5%
inv-pow78.5%
expm1-udef89.5%
Applied egg-rr89.5%
unpow-189.5%
associate-/r*89.7%
Simplified89.7%
clear-num89.8%
inv-pow89.8%
div-inv89.3%
clear-num89.3%
Applied egg-rr89.3%
unpow-189.3%
*-commutative89.3%
associate-*l/89.5%
associate-*r/90.0%
Simplified90.0%
Final simplification86.3%
(FPCore (x y z t) :precision binary64 (if (<= y -2e+176) x (- x (/ (expm1 z) (/ t y)))))
double code(double x, double y, double z, double t) {
double tmp;
if (y <= -2e+176) {
tmp = x;
} else {
tmp = x - (expm1(z) / (t / y));
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if (y <= -2e+176) {
tmp = x;
} else {
tmp = x - (Math.expm1(z) / (t / y));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if y <= -2e+176: tmp = x else: tmp = x - (math.expm1(z) / (t / y)) return tmp
function code(x, y, z, t) tmp = 0.0 if (y <= -2e+176) tmp = x; else tmp = Float64(x - Float64(expm1(z) / Float64(t / y))); end return tmp end
code[x_, y_, z_, t_] := If[LessEqual[y, -2e+176], x, N[(x - N[(N[(Exp[z] - 1), $MachinePrecision] / N[(t / y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -2 \cdot 10^{+176}:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\mathsf{expm1}\left(z\right)}{\frac{t}{y}}\\
\end{array}
\end{array}
if y < -2e176Initial program 50.6%
sub-neg50.6%
associate-+l+77.5%
cancel-sign-sub77.5%
log1p-def77.5%
cancel-sign-sub77.5%
+-commutative77.5%
unsub-neg77.5%
*-rgt-identity77.5%
distribute-lft-out--77.5%
expm1-def100.0%
Simplified100.0%
Taylor expanded in x around inf 56.8%
if -2e176 < y Initial program 60.6%
sub-neg60.6%
associate-+l+76.6%
cancel-sign-sub76.6%
log1p-def82.7%
cancel-sign-sub82.7%
+-commutative82.7%
unsub-neg82.7%
*-rgt-identity82.7%
distribute-lft-out--82.7%
expm1-def98.3%
Simplified98.3%
Taylor expanded in y around 0 78.5%
clear-num78.5%
inv-pow78.5%
expm1-udef89.5%
Applied egg-rr89.5%
unpow-189.5%
associate-/r*89.7%
Simplified89.7%
clear-num89.8%
add-cube-cbrt89.5%
*-un-lft-identity89.5%
times-frac89.5%
pow289.5%
Applied egg-rr89.5%
/-rgt-identity89.5%
associate-*r/89.5%
unpow289.5%
rem-3cbrt-lft89.8%
Simplified89.8%
Final simplification86.2%
(FPCore (x y z t) :precision binary64 (if (<= z -0.0114) x (- x (* z (/ y t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -0.0114) {
tmp = x;
} else {
tmp = x - (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) :: tmp
if (z <= (-0.0114d0)) then
tmp = x
else
tmp = x - (z * (y / t))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -0.0114) {
tmp = x;
} else {
tmp = x - (z * (y / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -0.0114: tmp = x else: tmp = x - (z * (y / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -0.0114) tmp = x; else tmp = Float64(x - Float64(z * Float64(y / t))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (z <= -0.0114) tmp = x; else tmp = x - (z * (y / t)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[z, -0.0114], x, N[(x - N[(z * N[(y / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -0.0114:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - z \cdot \frac{y}{t}\\
\end{array}
\end{array}
if z < -0.0114Initial program 84.7%
sub-neg84.7%
associate-+l+84.7%
cancel-sign-sub84.7%
log1p-def100.0%
cancel-sign-sub100.0%
+-commutative100.0%
unsub-neg100.0%
*-rgt-identity100.0%
distribute-lft-out--100.0%
expm1-def100.0%
Simplified100.0%
Taylor expanded in x around inf 68.0%
if -0.0114 < z Initial program 47.9%
sub-neg47.9%
associate-+l+73.0%
cancel-sign-sub73.0%
log1p-def73.8%
cancel-sign-sub73.8%
+-commutative73.8%
unsub-neg73.8%
*-rgt-identity73.8%
distribute-lft-out--73.8%
expm1-def97.7%
Simplified97.7%
Taylor expanded in z around 0 86.4%
associate-/l*87.3%
associate-/r/85.6%
Simplified85.6%
Final simplification80.0%
(FPCore (x y z t) :precision binary64 (if (<= z -0.000106) x (- x (/ y (/ t z)))))
double code(double x, double y, double z, double t) {
double tmp;
if (z <= -0.000106) {
tmp = x;
} else {
tmp = x - (y / (t / z));
}
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 <= (-0.000106d0)) then
tmp = x
else
tmp = x - (y / (t / z))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (z <= -0.000106) {
tmp = x;
} else {
tmp = x - (y / (t / z));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if z <= -0.000106: tmp = x else: tmp = x - (y / (t / z)) return tmp
function code(x, y, z, t) tmp = 0.0 if (z <= -0.000106) tmp = x; else tmp = Float64(x - Float64(y / Float64(t / z))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (z <= -0.000106) tmp = x; else tmp = x - (y / (t / z)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[z, -0.000106], x, N[(x - N[(y / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -0.000106:\\
\;\;\;\;x\\
\mathbf{else}:\\
\;\;\;\;x - \frac{y}{\frac{t}{z}}\\
\end{array}
\end{array}
if z < -1.06e-4Initial program 84.7%
sub-neg84.7%
associate-+l+84.7%
cancel-sign-sub84.7%
log1p-def100.0%
cancel-sign-sub100.0%
+-commutative100.0%
unsub-neg100.0%
*-rgt-identity100.0%
distribute-lft-out--100.0%
expm1-def100.0%
Simplified100.0%
Taylor expanded in x around inf 68.0%
if -1.06e-4 < z Initial program 47.9%
sub-neg47.9%
associate-+l+73.0%
cancel-sign-sub73.0%
log1p-def73.8%
cancel-sign-sub73.8%
+-commutative73.8%
unsub-neg73.8%
*-rgt-identity73.8%
distribute-lft-out--73.8%
expm1-def97.7%
Simplified97.7%
Taylor expanded in z around 0 86.4%
associate-/l*87.3%
Simplified87.3%
Final simplification81.1%
(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 59.5%
sub-neg59.5%
associate-+l+76.7%
cancel-sign-sub76.7%
log1p-def82.1%
cancel-sign-sub82.1%
+-commutative82.1%
unsub-neg82.1%
*-rgt-identity82.1%
distribute-lft-out--82.1%
expm1-def98.4%
Simplified98.4%
Taylor expanded in x around inf 71.1%
Final simplification71.1%
(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 2023322
(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)))