
(FPCore (a b) :precision binary64 (log (+ (exp a) (exp b))))
double code(double a, double b) {
return log((exp(a) + exp(b)));
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = log((exp(a) + exp(b)))
end function
public static double code(double a, double b) {
return Math.log((Math.exp(a) + Math.exp(b)));
}
def code(a, b): return math.log((math.exp(a) + math.exp(b)))
function code(a, b) return log(Float64(exp(a) + exp(b))) end
function tmp = code(a, b) tmp = log((exp(a) + exp(b))); end
code[a_, b_] := N[Log[N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(e^{a} + e^{b}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b) :precision binary64 (log (+ (exp a) (exp b))))
double code(double a, double b) {
return log((exp(a) + exp(b)));
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = log((exp(a) + exp(b)))
end function
public static double code(double a, double b) {
return Math.log((Math.exp(a) + Math.exp(b)));
}
def code(a, b): return math.log((math.exp(a) + math.exp(b)))
function code(a, b) return log(Float64(exp(a) + exp(b))) end
function tmp = code(a, b) tmp = log((exp(a) + exp(b))); end
code[a_, b_] := N[Log[N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(e^{a} + e^{b}\right)
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= (exp a) 0.0) (/ b (+ (exp a) 1.0)) (log (+ (exp a) (exp b)))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (exp(a) <= 0.0) {
tmp = b / (exp(a) + 1.0);
} else {
tmp = log((exp(a) + exp(b)));
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (exp(a) <= 0.0d0) then
tmp = b / (exp(a) + 1.0d0)
else
tmp = log((exp(a) + exp(b)))
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (Math.exp(a) <= 0.0) {
tmp = b / (Math.exp(a) + 1.0);
} else {
tmp = Math.log((Math.exp(a) + Math.exp(b)));
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if math.exp(a) <= 0.0: tmp = b / (math.exp(a) + 1.0) else: tmp = math.log((math.exp(a) + math.exp(b))) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (exp(a) <= 0.0) tmp = Float64(b / Float64(exp(a) + 1.0)); else tmp = log(Float64(exp(a) + exp(b))); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (exp(a) <= 0.0)
tmp = b / (exp(a) + 1.0);
else
tmp = log((exp(a) + exp(b)));
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[N[Exp[a], $MachinePrecision], 0.0], N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;e^{a} \leq 0:\\
\;\;\;\;\frac{b}{e^{a} + 1}\\
\mathbf{else}:\\
\;\;\;\;\log \left(e^{a} + e^{b}\right)\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (+ (log1p (exp a)) (/ b (+ (exp a) 1.0))))
assert(a < b);
double code(double a, double b) {
return log1p(exp(a)) + (b / (exp(a) + 1.0));
}
assert a < b;
public static double code(double a, double b) {
return Math.log1p(Math.exp(a)) + (b / (Math.exp(a) + 1.0));
}
[a, b] = sort([a, b]) def code(a, b): return math.log1p(math.exp(a)) + (b / (math.exp(a) + 1.0))
a, b = sort([a, b]) function code(a, b) return Float64(log1p(exp(a)) + Float64(b / Float64(exp(a) + 1.0))) end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := N[(N[Log[1 + N[Exp[a], $MachinePrecision]], $MachinePrecision] + N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\mathsf{log1p}\left(e^{a}\right) + \frac{b}{e^{a} + 1}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= (exp a) 0.0) (/ b (+ (exp a) 1.0)) (log1p (exp b))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (exp(a) <= 0.0) {
tmp = b / (exp(a) + 1.0);
} else {
tmp = log1p(exp(b));
}
return tmp;
}
assert a < b;
public static double code(double a, double b) {
double tmp;
if (Math.exp(a) <= 0.0) {
tmp = b / (Math.exp(a) + 1.0);
} else {
tmp = Math.log1p(Math.exp(b));
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if math.exp(a) <= 0.0: tmp = b / (math.exp(a) + 1.0) else: tmp = math.log1p(math.exp(b)) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (exp(a) <= 0.0) tmp = Float64(b / Float64(exp(a) + 1.0)); else tmp = log1p(exp(b)); end return tmp end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[N[Exp[a], $MachinePrecision], 0.0], N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[Log[1 + N[Exp[b], $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;e^{a} \leq 0:\\
\;\;\;\;\frac{b}{e^{a} + 1}\\
\mathbf{else}:\\
\;\;\;\;\mathsf{log1p}\left(e^{b}\right)\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= (exp a) 0.0) (/ b (+ (exp a) 1.0)) (+ (log 2.0) (* b (+ 0.5 (* a -0.25))))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (exp(a) <= 0.0) {
tmp = b / (exp(a) + 1.0);
} else {
tmp = log(2.0) + (b * (0.5 + (a * -0.25)));
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (exp(a) <= 0.0d0) then
tmp = b / (exp(a) + 1.0d0)
else
tmp = log(2.0d0) + (b * (0.5d0 + (a * (-0.25d0))))
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (Math.exp(a) <= 0.0) {
tmp = b / (Math.exp(a) + 1.0);
} else {
tmp = Math.log(2.0) + (b * (0.5 + (a * -0.25)));
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if math.exp(a) <= 0.0: tmp = b / (math.exp(a) + 1.0) else: tmp = math.log(2.0) + (b * (0.5 + (a * -0.25))) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (exp(a) <= 0.0) tmp = Float64(b / Float64(exp(a) + 1.0)); else tmp = Float64(log(2.0) + Float64(b * Float64(0.5 + Float64(a * -0.25)))); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (exp(a) <= 0.0)
tmp = b / (exp(a) + 1.0);
else
tmp = log(2.0) + (b * (0.5 + (a * -0.25)));
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[N[Exp[a], $MachinePrecision], 0.0], N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(b * N[(0.5 + N[(a * -0.25), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;e^{a} \leq 0:\\
\;\;\;\;\frac{b}{e^{a} + 1}\\
\mathbf{else}:\\
\;\;\;\;\log 2 + b \cdot \left(0.5 + a \cdot -0.25\right)\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= (exp a) 0.0) (/ b (+ (exp a) 1.0)) (+ (log 2.0) (* b (+ (* b 0.125) 0.5)))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (exp(a) <= 0.0) {
tmp = b / (exp(a) + 1.0);
} else {
tmp = log(2.0) + (b * ((b * 0.125) + 0.5));
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (exp(a) <= 0.0d0) then
tmp = b / (exp(a) + 1.0d0)
else
tmp = log(2.0d0) + (b * ((b * 0.125d0) + 0.5d0))
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (Math.exp(a) <= 0.0) {
tmp = b / (Math.exp(a) + 1.0);
} else {
tmp = Math.log(2.0) + (b * ((b * 0.125) + 0.5));
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if math.exp(a) <= 0.0: tmp = b / (math.exp(a) + 1.0) else: tmp = math.log(2.0) + (b * ((b * 0.125) + 0.5)) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (exp(a) <= 0.0) tmp = Float64(b / Float64(exp(a) + 1.0)); else tmp = Float64(log(2.0) + Float64(b * Float64(Float64(b * 0.125) + 0.5))); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (exp(a) <= 0.0)
tmp = b / (exp(a) + 1.0);
else
tmp = log(2.0) + (b * ((b * 0.125) + 0.5));
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[N[Exp[a], $MachinePrecision], 0.0], N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(b * N[(N[(b * 0.125), $MachinePrecision] + 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;e^{a} \leq 0:\\
\;\;\;\;\frac{b}{e^{a} + 1}\\
\mathbf{else}:\\
\;\;\;\;\log 2 + b \cdot \left(b \cdot 0.125 + 0.5\right)\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= (exp a) 0.0) (/ b (+ (exp a) 1.0)) (+ (log 2.0) (* b 0.5))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (exp(a) <= 0.0) {
tmp = b / (exp(a) + 1.0);
} else {
tmp = log(2.0) + (b * 0.5);
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (exp(a) <= 0.0d0) then
tmp = b / (exp(a) + 1.0d0)
else
tmp = log(2.0d0) + (b * 0.5d0)
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (Math.exp(a) <= 0.0) {
tmp = b / (Math.exp(a) + 1.0);
} else {
tmp = Math.log(2.0) + (b * 0.5);
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if math.exp(a) <= 0.0: tmp = b / (math.exp(a) + 1.0) else: tmp = math.log(2.0) + (b * 0.5) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (exp(a) <= 0.0) tmp = Float64(b / Float64(exp(a) + 1.0)); else tmp = Float64(log(2.0) + Float64(b * 0.5)); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (exp(a) <= 0.0)
tmp = b / (exp(a) + 1.0);
else
tmp = log(2.0) + (b * 0.5);
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[N[Exp[a], $MachinePrecision], 0.0], N[(b / N[(N[Exp[a], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(b * 0.5), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;e^{a} \leq 0:\\
\;\;\;\;\frac{b}{e^{a} + 1}\\
\mathbf{else}:\\
\;\;\;\;\log 2 + b \cdot 0.5\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= a -115.0) (* b 0.5) (+ (log 2.0) (* b 0.5))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (a <= -115.0) {
tmp = b * 0.5;
} else {
tmp = log(2.0) + (b * 0.5);
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (a <= (-115.0d0)) then
tmp = b * 0.5d0
else
tmp = log(2.0d0) + (b * 0.5d0)
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (a <= -115.0) {
tmp = b * 0.5;
} else {
tmp = Math.log(2.0) + (b * 0.5);
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if a <= -115.0: tmp = b * 0.5 else: tmp = math.log(2.0) + (b * 0.5) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (a <= -115.0) tmp = Float64(b * 0.5); else tmp = Float64(log(2.0) + Float64(b * 0.5)); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (a <= -115.0)
tmp = b * 0.5;
else
tmp = log(2.0) + (b * 0.5);
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[a, -115.0], N[(b * 0.5), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(b * 0.5), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;a \leq -115:\\
\;\;\;\;b \cdot 0.5\\
\mathbf{else}:\\
\;\;\;\;\log 2 + b \cdot 0.5\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= a -110.0) (* b 0.5) (log (+ b 2.0))))
assert(a < b);
double code(double a, double b) {
double tmp;
if (a <= -110.0) {
tmp = b * 0.5;
} else {
tmp = log((b + 2.0));
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (a <= (-110.0d0)) then
tmp = b * 0.5d0
else
tmp = log((b + 2.0d0))
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (a <= -110.0) {
tmp = b * 0.5;
} else {
tmp = Math.log((b + 2.0));
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if a <= -110.0: tmp = b * 0.5 else: tmp = math.log((b + 2.0)) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (a <= -110.0) tmp = Float64(b * 0.5); else tmp = log(Float64(b + 2.0)); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (a <= -110.0)
tmp = b * 0.5;
else
tmp = log((b + 2.0));
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[a, -110.0], N[(b * 0.5), $MachinePrecision], N[Log[N[(b + 2.0), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;a \leq -110:\\
\;\;\;\;b \cdot 0.5\\
\mathbf{else}:\\
\;\;\;\;\log \left(b + 2\right)\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (if (<= a -170.0) (* b 0.5) (log 2.0)))
assert(a < b);
double code(double a, double b) {
double tmp;
if (a <= -170.0) {
tmp = b * 0.5;
} else {
tmp = log(2.0);
}
return tmp;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8) :: tmp
if (a <= (-170.0d0)) then
tmp = b * 0.5d0
else
tmp = log(2.0d0)
end if
code = tmp
end function
assert a < b;
public static double code(double a, double b) {
double tmp;
if (a <= -170.0) {
tmp = b * 0.5;
} else {
tmp = Math.log(2.0);
}
return tmp;
}
[a, b] = sort([a, b]) def code(a, b): tmp = 0 if a <= -170.0: tmp = b * 0.5 else: tmp = math.log(2.0) return tmp
a, b = sort([a, b]) function code(a, b) tmp = 0.0 if (a <= -170.0) tmp = Float64(b * 0.5); else tmp = log(2.0); end return tmp end
a, b = num2cell(sort([a, b])){:}
function tmp_2 = code(a, b)
tmp = 0.0;
if (a <= -170.0)
tmp = b * 0.5;
else
tmp = log(2.0);
end
tmp_2 = tmp;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := If[LessEqual[a, -170.0], N[(b * 0.5), $MachinePrecision], N[Log[2.0], $MachinePrecision]]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
\begin{array}{l}
\mathbf{if}\;a \leq -170:\\
\;\;\;\;b \cdot 0.5\\
\mathbf{else}:\\
\;\;\;\;\log 2\\
\end{array}
\end{array}
NOTE: a and b should be sorted in increasing order before calling this function. (FPCore (a b) :precision binary64 (* b 0.5))
assert(a < b);
double code(double a, double b) {
return b * 0.5;
}
NOTE: a and b should be sorted in increasing order before calling this function.
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = b * 0.5d0
end function
assert a < b;
public static double code(double a, double b) {
return b * 0.5;
}
[a, b] = sort([a, b]) def code(a, b): return b * 0.5
a, b = sort([a, b]) function code(a, b) return Float64(b * 0.5) end
a, b = num2cell(sort([a, b])){:}
function tmp = code(a, b)
tmp = b * 0.5;
end
NOTE: a and b should be sorted in increasing order before calling this function. code[a_, b_] := N[(b * 0.5), $MachinePrecision]
\begin{array}{l}
[a, b] = \mathsf{sort}([a, b])\\
\\
b \cdot 0.5
\end{array}
herbie shell --seed 2023348
(FPCore (a b)
:name "symmetry log of sum of exp"
:precision binary64
(log (+ (exp a) (exp b))))