
(FPCore (a b) :precision binary64 (/ (exp a) (+ (exp a) (exp b))))
double code(double a, double b) {
return exp(a) / (exp(a) + exp(b));
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = exp(a) / (exp(a) + exp(b))
end function
public static double code(double a, double b) {
return Math.exp(a) / (Math.exp(a) + Math.exp(b));
}
def code(a, b): return math.exp(a) / (math.exp(a) + math.exp(b))
function code(a, b) return Float64(exp(a) / Float64(exp(a) + exp(b))) end
function tmp = code(a, b) tmp = exp(a) / (exp(a) + exp(b)); end
code[a_, b_] := N[(N[Exp[a], $MachinePrecision] / N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{e^{a}}{e^{a} + e^{b}}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b) :precision binary64 (/ (exp a) (+ (exp a) (exp b))))
double code(double a, double b) {
return exp(a) / (exp(a) + exp(b));
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = exp(a) / (exp(a) + exp(b))
end function
public static double code(double a, double b) {
return Math.exp(a) / (Math.exp(a) + Math.exp(b));
}
def code(a, b): return math.exp(a) / (math.exp(a) + math.exp(b))
function code(a, b) return Float64(exp(a) / Float64(exp(a) + exp(b))) end
function tmp = code(a, b) tmp = exp(a) / (exp(a) + exp(b)); end
code[a_, b_] := N[(N[Exp[a], $MachinePrecision] / N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{e^{a}}{e^{a} + e^{b}}
\end{array}
(FPCore (a b) :precision binary64 (exp (- (log1p (exp (- b a))))))
double code(double a, double b) {
return exp(-log1p(exp((b - a))));
}
public static double code(double a, double b) {
return Math.exp(-Math.log1p(Math.exp((b - a))));
}
def code(a, b): return math.exp(-math.log1p(math.exp((b - a))))
function code(a, b) return exp(Float64(-log1p(exp(Float64(b - a))))) end
code[a_, b_] := N[Exp[(-N[Log[1 + N[Exp[N[(b - a), $MachinePrecision]], $MachinePrecision]], $MachinePrecision])], $MachinePrecision]
\begin{array}{l}
\\
e^{-\mathsf{log1p}\left(e^{b - a}\right)}
\end{array}
Initial program 99.6%
*-lft-identity99.6%
associate-*l/99.6%
associate-/r/99.6%
remove-double-neg99.6%
unsub-neg99.6%
div-sub71.1%
*-lft-identity71.1%
associate-*l/71.1%
lft-mult-inverse99.6%
sub-neg99.6%
distribute-frac-neg99.6%
remove-double-neg99.6%
div-exp100.0%
Simplified100.0%
add-exp-log100.0%
log-rec100.0%
log1p-define100.0%
Applied egg-rr100.0%
Final simplification100.0%
(FPCore (a b) :precision binary64 (if (<= a -750000.0) (/ (exp a) a) (/ 1.0 (+ 1.0 (exp b)))))
double code(double a, double b) {
double tmp;
if (a <= -750000.0) {
tmp = exp(a) / a;
} else {
tmp = 1.0 / (1.0 + exp(b));
}
return tmp;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (a <= (-750000.0d0)) then
tmp = exp(a) / a
else
tmp = 1.0d0 / (1.0d0 + exp(b))
end if
code = tmp
end function
public static double code(double a, double b) {
double tmp;
if (a <= -750000.0) {
tmp = Math.exp(a) / a;
} else {
tmp = 1.0 / (1.0 + Math.exp(b));
}
return tmp;
}
def code(a, b): tmp = 0 if a <= -750000.0: tmp = math.exp(a) / a else: tmp = 1.0 / (1.0 + math.exp(b)) return tmp
function code(a, b) tmp = 0.0 if (a <= -750000.0) tmp = Float64(exp(a) / a); else tmp = Float64(1.0 / Float64(1.0 + exp(b))); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (a <= -750000.0) tmp = exp(a) / a; else tmp = 1.0 / (1.0 + exp(b)); end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[a, -750000.0], N[(N[Exp[a], $MachinePrecision] / a), $MachinePrecision], N[(1.0 / N[(1.0 + N[Exp[b], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;a \leq -750000:\\
\;\;\;\;\frac{e^{a}}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{1 + e^{b}}\\
\end{array}
\end{array}
if a < -7.5e5Initial program 100.0%
Taylor expanded in b around 0 100.0%
Taylor expanded in a around 0 100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in a around inf 100.0%
if -7.5e5 < a Initial program 99.4%
*-lft-identity99.4%
associate-*l/99.4%
associate-/r/99.4%
remove-double-neg99.4%
unsub-neg99.4%
div-sub98.9%
*-lft-identity98.9%
associate-*l/98.9%
lft-mult-inverse99.4%
sub-neg99.4%
distribute-frac-neg99.4%
remove-double-neg99.4%
div-exp99.9%
Simplified99.9%
Taylor expanded in a around 0 98.0%
Final simplification98.5%
(FPCore (a b) :precision binary64 (if (<= a -2.2) (/ (exp a) a) (+ 0.5 (* a 0.25))))
double code(double a, double b) {
double tmp;
if (a <= -2.2) {
tmp = exp(a) / a;
} else {
tmp = 0.5 + (a * 0.25);
}
return tmp;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (a <= (-2.2d0)) then
tmp = exp(a) / a
else
tmp = 0.5d0 + (a * 0.25d0)
end if
code = tmp
end function
public static double code(double a, double b) {
double tmp;
if (a <= -2.2) {
tmp = Math.exp(a) / a;
} else {
tmp = 0.5 + (a * 0.25);
}
return tmp;
}
def code(a, b): tmp = 0 if a <= -2.2: tmp = math.exp(a) / a else: tmp = 0.5 + (a * 0.25) return tmp
function code(a, b) tmp = 0.0 if (a <= -2.2) tmp = Float64(exp(a) / a); else tmp = Float64(0.5 + Float64(a * 0.25)); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (a <= -2.2) tmp = exp(a) / a; else tmp = 0.5 + (a * 0.25); end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[a, -2.2], N[(N[Exp[a], $MachinePrecision] / a), $MachinePrecision], N[(0.5 + N[(a * 0.25), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;a \leq -2.2:\\
\;\;\;\;\frac{e^{a}}{a}\\
\mathbf{else}:\\
\;\;\;\;0.5 + a \cdot 0.25\\
\end{array}
\end{array}
if a < -2.2000000000000002Initial program 100.0%
Taylor expanded in b around 0 100.0%
Taylor expanded in a around 0 100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in a around inf 100.0%
if -2.2000000000000002 < a Initial program 99.4%
*-lft-identity99.4%
associate-*l/99.4%
associate-/r/99.4%
remove-double-neg99.4%
unsub-neg99.4%
div-sub99.4%
*-lft-identity99.4%
associate-*l/99.4%
lft-mult-inverse99.4%
sub-neg99.4%
distribute-frac-neg99.4%
remove-double-neg99.4%
div-exp99.9%
Simplified99.9%
Taylor expanded in b around 0 62.3%
Taylor expanded in a around 0 62.0%
*-commutative62.0%
Simplified62.0%
Final simplification72.9%
(FPCore (a b) :precision binary64 (/ 1.0 (+ (exp (- b a)) 1.0)))
double code(double a, double b) {
return 1.0 / (exp((b - a)) + 1.0);
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = 1.0d0 / (exp((b - a)) + 1.0d0)
end function
public static double code(double a, double b) {
return 1.0 / (Math.exp((b - a)) + 1.0);
}
def code(a, b): return 1.0 / (math.exp((b - a)) + 1.0)
function code(a, b) return Float64(1.0 / Float64(exp(Float64(b - a)) + 1.0)) end
function tmp = code(a, b) tmp = 1.0 / (exp((b - a)) + 1.0); end
code[a_, b_] := N[(1.0 / N[(N[Exp[N[(b - a), $MachinePrecision]], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{e^{b - a} + 1}
\end{array}
Initial program 99.6%
*-lft-identity99.6%
associate-*l/99.6%
associate-/r/99.6%
remove-double-neg99.6%
unsub-neg99.6%
div-sub71.1%
*-lft-identity71.1%
associate-*l/71.1%
lft-mult-inverse99.6%
sub-neg99.6%
distribute-frac-neg99.6%
remove-double-neg99.6%
div-exp100.0%
Simplified100.0%
Final simplification100.0%
(FPCore (a b) :precision binary64 (if (<= b -6.2e-12) 1.0 (+ 0.5 (* a 0.25))))
double code(double a, double b) {
double tmp;
if (b <= -6.2e-12) {
tmp = 1.0;
} else {
tmp = 0.5 + (a * 0.25);
}
return tmp;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (b <= (-6.2d-12)) then
tmp = 1.0d0
else
tmp = 0.5d0 + (a * 0.25d0)
end if
code = tmp
end function
public static double code(double a, double b) {
double tmp;
if (b <= -6.2e-12) {
tmp = 1.0;
} else {
tmp = 0.5 + (a * 0.25);
}
return tmp;
}
def code(a, b): tmp = 0 if b <= -6.2e-12: tmp = 1.0 else: tmp = 0.5 + (a * 0.25) return tmp
function code(a, b) tmp = 0.0 if (b <= -6.2e-12) tmp = 1.0; else tmp = Float64(0.5 + Float64(a * 0.25)); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (b <= -6.2e-12) tmp = 1.0; else tmp = 0.5 + (a * 0.25); end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[b, -6.2e-12], 1.0, N[(0.5 + N[(a * 0.25), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -6.2 \cdot 10^{-12}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;0.5 + a \cdot 0.25\\
\end{array}
\end{array}
if b < -6.2000000000000002e-12Initial program 100.0%
*-lft-identity100.0%
associate-*l/100.0%
associate-/r/100.0%
remove-double-neg100.0%
unsub-neg100.0%
div-sub97.1%
*-lft-identity97.1%
associate-*l/97.1%
lft-mult-inverse100.0%
sub-neg100.0%
distribute-frac-neg100.0%
remove-double-neg100.0%
div-exp100.0%
Simplified100.0%
add-exp-log100.0%
log-rec100.0%
log1p-define100.0%
Applied egg-rr100.0%
exp-neg100.0%
log1p-undefine100.0%
add-exp-log100.0%
add-sqr-sqrt100.0%
associate-/r*100.0%
Applied egg-rr97.2%
*-inverses97.2%
Simplified97.2%
if -6.2000000000000002e-12 < b Initial program 99.5%
*-lft-identity99.5%
associate-*l/99.5%
associate-/r/99.5%
remove-double-neg99.5%
unsub-neg99.5%
div-sub66.9%
*-lft-identity66.9%
associate-*l/66.9%
lft-mult-inverse99.5%
sub-neg99.5%
distribute-frac-neg99.5%
remove-double-neg99.5%
div-exp100.0%
Simplified100.0%
Taylor expanded in b around 0 81.3%
Taylor expanded in a around 0 49.2%
*-commutative49.2%
Simplified49.2%
Final simplification55.8%
(FPCore (a b) :precision binary64 (if (<= b -1.22) 1.0 (/ 1.0 (- 2.0 a))))
double code(double a, double b) {
double tmp;
if (b <= -1.22) {
tmp = 1.0;
} else {
tmp = 1.0 / (2.0 - a);
}
return tmp;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (b <= (-1.22d0)) then
tmp = 1.0d0
else
tmp = 1.0d0 / (2.0d0 - a)
end if
code = tmp
end function
public static double code(double a, double b) {
double tmp;
if (b <= -1.22) {
tmp = 1.0;
} else {
tmp = 1.0 / (2.0 - a);
}
return tmp;
}
def code(a, b): tmp = 0 if b <= -1.22: tmp = 1.0 else: tmp = 1.0 / (2.0 - a) return tmp
function code(a, b) tmp = 0.0 if (b <= -1.22) tmp = 1.0; else tmp = Float64(1.0 / Float64(2.0 - a)); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (b <= -1.22) tmp = 1.0; else tmp = 1.0 / (2.0 - a); end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[b, -1.22], 1.0, N[(1.0 / N[(2.0 - a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -1.22:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{2 - a}\\
\end{array}
\end{array}
if b < -1.21999999999999997Initial program 100.0%
*-lft-identity100.0%
associate-*l/100.0%
associate-/r/100.0%
remove-double-neg100.0%
unsub-neg100.0%
div-sub100.0%
*-lft-identity100.0%
associate-*l/100.0%
lft-mult-inverse100.0%
sub-neg100.0%
distribute-frac-neg100.0%
remove-double-neg100.0%
div-exp100.0%
Simplified100.0%
add-exp-log100.0%
log-rec100.0%
log1p-define100.0%
Applied egg-rr100.0%
exp-neg100.0%
log1p-undefine100.0%
add-exp-log100.0%
add-sqr-sqrt100.0%
associate-/r*100.0%
Applied egg-rr100.0%
*-inverses100.0%
Simplified100.0%
if -1.21999999999999997 < b Initial program 99.5%
*-lft-identity99.5%
associate-*l/99.5%
associate-/r/99.5%
remove-double-neg99.5%
unsub-neg99.5%
div-sub66.6%
*-lft-identity66.6%
associate-*l/66.6%
lft-mult-inverse99.5%
sub-neg99.5%
distribute-frac-neg99.5%
remove-double-neg99.5%
div-exp100.0%
Simplified100.0%
Taylor expanded in b around 0 81.3%
Taylor expanded in a around 0 49.6%
neg-mul-149.6%
unsub-neg49.6%
Simplified49.6%
Final simplification56.3%
(FPCore (a b) :precision binary64 (if (<= b -1.1) 1.0 0.5))
double code(double a, double b) {
double tmp;
if (b <= -1.1) {
tmp = 1.0;
} else {
tmp = 0.5;
}
return tmp;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (b <= (-1.1d0)) then
tmp = 1.0d0
else
tmp = 0.5d0
end if
code = tmp
end function
public static double code(double a, double b) {
double tmp;
if (b <= -1.1) {
tmp = 1.0;
} else {
tmp = 0.5;
}
return tmp;
}
def code(a, b): tmp = 0 if b <= -1.1: tmp = 1.0 else: tmp = 0.5 return tmp
function code(a, b) tmp = 0.0 if (b <= -1.1) tmp = 1.0; else tmp = 0.5; end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (b <= -1.1) tmp = 1.0; else tmp = 0.5; end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[b, -1.1], 1.0, 0.5]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -1.1:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;0.5\\
\end{array}
\end{array}
if b < -1.1000000000000001Initial program 100.0%
*-lft-identity100.0%
associate-*l/100.0%
associate-/r/100.0%
remove-double-neg100.0%
unsub-neg100.0%
div-sub100.0%
*-lft-identity100.0%
associate-*l/100.0%
lft-mult-inverse100.0%
sub-neg100.0%
distribute-frac-neg100.0%
remove-double-neg100.0%
div-exp100.0%
Simplified100.0%
add-exp-log100.0%
log-rec100.0%
log1p-define100.0%
Applied egg-rr100.0%
exp-neg100.0%
log1p-undefine100.0%
add-exp-log100.0%
add-sqr-sqrt100.0%
associate-/r*100.0%
Applied egg-rr100.0%
*-inverses100.0%
Simplified100.0%
if -1.1000000000000001 < b Initial program 99.5%
*-lft-identity99.5%
associate-*l/99.5%
associate-/r/99.5%
remove-double-neg99.5%
unsub-neg99.5%
div-sub66.6%
*-lft-identity66.6%
associate-*l/66.6%
lft-mult-inverse99.5%
sub-neg99.5%
distribute-frac-neg99.5%
remove-double-neg99.5%
div-exp100.0%
Simplified100.0%
Taylor expanded in a around 0 74.8%
Taylor expanded in b around 0 47.8%
Final simplification54.8%
(FPCore (a b) :precision binary64 0.5)
double code(double a, double b) {
return 0.5;
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = 0.5d0
end function
public static double code(double a, double b) {
return 0.5;
}
def code(a, b): return 0.5
function code(a, b) return 0.5 end
function tmp = code(a, b) tmp = 0.5; end
code[a_, b_] := 0.5
\begin{array}{l}
\\
0.5
\end{array}
Initial program 99.6%
*-lft-identity99.6%
associate-*l/99.6%
associate-/r/99.6%
remove-double-neg99.6%
unsub-neg99.6%
div-sub71.1%
*-lft-identity71.1%
associate-*l/71.1%
lft-mult-inverse99.6%
sub-neg99.6%
distribute-frac-neg99.6%
remove-double-neg99.6%
div-exp100.0%
Simplified100.0%
Taylor expanded in a around 0 78.1%
Taylor expanded in b around 0 44.0%
Final simplification44.0%
(FPCore (a b) :precision binary64 (/ 1.0 (+ 1.0 (exp (- b a)))))
double code(double a, double b) {
return 1.0 / (1.0 + exp((b - a)));
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = 1.0d0 / (1.0d0 + exp((b - a)))
end function
public static double code(double a, double b) {
return 1.0 / (1.0 + Math.exp((b - a)));
}
def code(a, b): return 1.0 / (1.0 + math.exp((b - a)))
function code(a, b) return Float64(1.0 / Float64(1.0 + exp(Float64(b - a)))) end
function tmp = code(a, b) tmp = 1.0 / (1.0 + exp((b - a))); end
code[a_, b_] := N[(1.0 / N[(1.0 + N[Exp[N[(b - a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{1 + e^{b - a}}
\end{array}
herbie shell --seed 2024050
(FPCore (a b)
:name "Quotient of sum of exps"
:precision binary64
:alt
(/ 1.0 (+ 1.0 (exp (- b a))))
(/ (exp a) (+ (exp a) (exp b))))