
(FPCore (x y) :precision binary64 (- (log (+ 1.0 (exp x))) (* x y)))
double code(double x, double y) {
return log((1.0 + exp(x))) - (x * y);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = log((1.0d0 + exp(x))) - (x * y)
end function
public static double code(double x, double y) {
return Math.log((1.0 + Math.exp(x))) - (x * y);
}
def code(x, y): return math.log((1.0 + math.exp(x))) - (x * y)
function code(x, y) return Float64(log(Float64(1.0 + exp(x))) - Float64(x * y)) end
function tmp = code(x, y) tmp = log((1.0 + exp(x))) - (x * y); end
code[x_, y_] := N[(N[Log[N[(1.0 + N[Exp[x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[(x * y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\log \left(1 + e^{x}\right) - x \cdot y
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y) :precision binary64 (- (log (+ 1.0 (exp x))) (* x y)))
double code(double x, double y) {
return log((1.0 + exp(x))) - (x * y);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = log((1.0d0 + exp(x))) - (x * y)
end function
public static double code(double x, double y) {
return Math.log((1.0 + Math.exp(x))) - (x * y);
}
def code(x, y): return math.log((1.0 + math.exp(x))) - (x * y)
function code(x, y) return Float64(log(Float64(1.0 + exp(x))) - Float64(x * y)) end
function tmp = code(x, y) tmp = log((1.0 + exp(x))) - (x * y); end
code[x_, y_] := N[(N[Log[N[(1.0 + N[Exp[x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[(x * y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\log \left(1 + e^{x}\right) - x \cdot y
\end{array}
(FPCore (x y) :precision binary64 (if (<= x -340.0) (* x (- y)) (+ (* x (- 0.5 y)) (log 2.0))))
double code(double x, double y) {
double tmp;
if (x <= -340.0) {
tmp = x * -y;
} else {
tmp = (x * (0.5 - y)) + log(2.0);
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-340.0d0)) then
tmp = x * -y
else
tmp = (x * (0.5d0 - y)) + log(2.0d0)
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -340.0) {
tmp = x * -y;
} else {
tmp = (x * (0.5 - y)) + Math.log(2.0);
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -340.0: tmp = x * -y else: tmp = (x * (0.5 - y)) + math.log(2.0) return tmp
function code(x, y) tmp = 0.0 if (x <= -340.0) tmp = Float64(x * Float64(-y)); else tmp = Float64(Float64(x * Float64(0.5 - y)) + log(2.0)); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -340.0) tmp = x * -y; else tmp = (x * (0.5 - y)) + log(2.0); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -340.0], N[(x * (-y)), $MachinePrecision], N[(N[(x * N[(0.5 - y), $MachinePrecision]), $MachinePrecision] + N[Log[2.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -340:\\
\;\;\;\;x \cdot \left(-y\right)\\
\mathbf{else}:\\
\;\;\;\;x \cdot \left(0.5 - y\right) + \log 2\\
\end{array}
\end{array}
if x < -340Initial program 100.0%
log1p-def100.0%
Simplified100.0%
Taylor expanded in x around inf 100.0%
mul-1-neg100.0%
distribute-rgt-neg-out100.0%
Simplified100.0%
if -340 < x Initial program 98.3%
log1p-def98.3%
Simplified98.3%
Taylor expanded in x around 0 99.6%
Final simplification99.8%
(FPCore (x y) :precision binary64 (fma x (- y) (log1p (exp x))))
double code(double x, double y) {
return fma(x, -y, log1p(exp(x)));
}
function code(x, y) return fma(x, Float64(-y), log1p(exp(x))) end
code[x_, y_] := N[(x * (-y) + N[Log[1 + N[Exp[x], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(x, -y, \mathsf{log1p}\left(e^{x}\right)\right)
\end{array}
Initial program 98.8%
sub-neg98.8%
+-commutative98.8%
distribute-rgt-neg-in98.8%
fma-def98.9%
log1p-def98.9%
Simplified98.9%
Final simplification98.9%
(FPCore (x y) :precision binary64 (- (log1p (exp x)) (* x y)))
double code(double x, double y) {
return log1p(exp(x)) - (x * y);
}
public static double code(double x, double y) {
return Math.log1p(Math.exp(x)) - (x * y);
}
def code(x, y): return math.log1p(math.exp(x)) - (x * y)
function code(x, y) return Float64(log1p(exp(x)) - Float64(x * y)) end
code[x_, y_] := N[(N[Log[1 + N[Exp[x], $MachinePrecision]], $MachinePrecision] - N[(x * y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{log1p}\left(e^{x}\right) - x \cdot y
\end{array}
Initial program 98.8%
log1p-def98.9%
Simplified98.9%
Final simplification98.9%
(FPCore (x y) :precision binary64 (if (<= x -340.0) (* x (- y)) (- (log 2.0) (* x y))))
double code(double x, double y) {
double tmp;
if (x <= -340.0) {
tmp = x * -y;
} else {
tmp = log(2.0) - (x * y);
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-340.0d0)) then
tmp = x * -y
else
tmp = log(2.0d0) - (x * y)
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -340.0) {
tmp = x * -y;
} else {
tmp = Math.log(2.0) - (x * y);
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -340.0: tmp = x * -y else: tmp = math.log(2.0) - (x * y) return tmp
function code(x, y) tmp = 0.0 if (x <= -340.0) tmp = Float64(x * Float64(-y)); else tmp = Float64(log(2.0) - Float64(x * y)); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -340.0) tmp = x * -y; else tmp = log(2.0) - (x * y); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -340.0], N[(x * (-y)), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] - N[(x * y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -340:\\
\;\;\;\;x \cdot \left(-y\right)\\
\mathbf{else}:\\
\;\;\;\;\log 2 - x \cdot y\\
\end{array}
\end{array}
if x < -340Initial program 100.0%
log1p-def100.0%
Simplified100.0%
Taylor expanded in x around inf 100.0%
mul-1-neg100.0%
distribute-rgt-neg-out100.0%
Simplified100.0%
if -340 < x Initial program 98.3%
log1p-def98.3%
Simplified98.3%
Taylor expanded in x around 0 99.4%
Final simplification99.6%
(FPCore (x y) :precision binary64 (if (<= x -1e-61) (* x (- y)) (if (<= x 1.7e-68) (log 2.0) (* x (- 0.5 y)))))
double code(double x, double y) {
double tmp;
if (x <= -1e-61) {
tmp = x * -y;
} else if (x <= 1.7e-68) {
tmp = log(2.0);
} else {
tmp = x * (0.5 - y);
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-1d-61)) then
tmp = x * -y
else if (x <= 1.7d-68) then
tmp = log(2.0d0)
else
tmp = x * (0.5d0 - y)
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -1e-61) {
tmp = x * -y;
} else if (x <= 1.7e-68) {
tmp = Math.log(2.0);
} else {
tmp = x * (0.5 - y);
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -1e-61: tmp = x * -y elif x <= 1.7e-68: tmp = math.log(2.0) else: tmp = x * (0.5 - y) return tmp
function code(x, y) tmp = 0.0 if (x <= -1e-61) tmp = Float64(x * Float64(-y)); elseif (x <= 1.7e-68) tmp = log(2.0); else tmp = Float64(x * Float64(0.5 - y)); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -1e-61) tmp = x * -y; elseif (x <= 1.7e-68) tmp = log(2.0); else tmp = x * (0.5 - y); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -1e-61], N[(x * (-y)), $MachinePrecision], If[LessEqual[x, 1.7e-68], N[Log[2.0], $MachinePrecision], N[(x * N[(0.5 - y), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \cdot 10^{-61}:\\
\;\;\;\;x \cdot \left(-y\right)\\
\mathbf{elif}\;x \leq 1.7 \cdot 10^{-68}:\\
\;\;\;\;\log 2\\
\mathbf{else}:\\
\;\;\;\;x \cdot \left(0.5 - y\right)\\
\end{array}
\end{array}
if x < -1e-61Initial program 100.0%
log1p-def100.0%
Simplified100.0%
Taylor expanded in x around inf 95.1%
mul-1-neg95.1%
distribute-rgt-neg-out95.1%
Simplified95.1%
if -1e-61 < x < 1.70000000000000009e-68Initial program 100.0%
log1p-def100.0%
Simplified100.0%
Taylor expanded in x around 0 100.0%
Taylor expanded in y around 0 84.2%
Taylor expanded in x around 0 84.2%
if 1.70000000000000009e-68 < x Initial program 90.6%
log1p-def90.6%
Simplified90.6%
Taylor expanded in x around 0 100.0%
Taylor expanded in x around inf 85.3%
Final simplification88.4%
(FPCore (x y) :precision binary64 (* x (- y)))
double code(double x, double y) {
return x * -y;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = x * -y
end function
public static double code(double x, double y) {
return x * -y;
}
def code(x, y): return x * -y
function code(x, y) return Float64(x * Float64(-y)) end
function tmp = code(x, y) tmp = x * -y; end
code[x_, y_] := N[(x * (-y)), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(-y\right)
\end{array}
Initial program 98.8%
log1p-def98.9%
Simplified98.9%
Taylor expanded in x around inf 54.6%
mul-1-neg54.6%
distribute-rgt-neg-out54.6%
Simplified54.6%
Final simplification54.6%
(FPCore (x y) :precision binary64 (* x 0.5))
double code(double x, double y) {
return x * 0.5;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = x * 0.5d0
end function
public static double code(double x, double y) {
return x * 0.5;
}
def code(x, y): return x * 0.5
function code(x, y) return Float64(x * 0.5) end
function tmp = code(x, y) tmp = x * 0.5; end
code[x_, y_] := N[(x * 0.5), $MachinePrecision]
\begin{array}{l}
\\
x \cdot 0.5
\end{array}
Initial program 98.8%
log1p-def98.9%
Simplified98.9%
Taylor expanded in x around 0 82.3%
Taylor expanded in y around 0 47.7%
Taylor expanded in x around inf 3.5%
Final simplification3.5%
(FPCore (x y) :precision binary64 (if (<= x 0.0) (- (log (+ 1.0 (exp x))) (* x y)) (- (log (+ 1.0 (exp (- x)))) (* (- x) (- 1.0 y)))))
double code(double x, double y) {
double tmp;
if (x <= 0.0) {
tmp = log((1.0 + exp(x))) - (x * y);
} else {
tmp = log((1.0 + exp(-x))) - (-x * (1.0 - y));
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= 0.0d0) then
tmp = log((1.0d0 + exp(x))) - (x * y)
else
tmp = log((1.0d0 + exp(-x))) - (-x * (1.0d0 - y))
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= 0.0) {
tmp = Math.log((1.0 + Math.exp(x))) - (x * y);
} else {
tmp = Math.log((1.0 + Math.exp(-x))) - (-x * (1.0 - y));
}
return tmp;
}
def code(x, y): tmp = 0 if x <= 0.0: tmp = math.log((1.0 + math.exp(x))) - (x * y) else: tmp = math.log((1.0 + math.exp(-x))) - (-x * (1.0 - y)) return tmp
function code(x, y) tmp = 0.0 if (x <= 0.0) tmp = Float64(log(Float64(1.0 + exp(x))) - Float64(x * y)); else tmp = Float64(log(Float64(1.0 + exp(Float64(-x)))) - Float64(Float64(-x) * Float64(1.0 - y))); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= 0.0) tmp = log((1.0 + exp(x))) - (x * y); else tmp = log((1.0 + exp(-x))) - (-x * (1.0 - y)); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, 0.0], N[(N[Log[N[(1.0 + N[Exp[x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[(x * y), $MachinePrecision]), $MachinePrecision], N[(N[Log[N[(1.0 + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[((-x) * N[(1.0 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 0:\\
\;\;\;\;\log \left(1 + e^{x}\right) - x \cdot y\\
\mathbf{else}:\\
\;\;\;\;\log \left(1 + e^{-x}\right) - \left(-x\right) \cdot \left(1 - y\right)\\
\end{array}
\end{array}
herbie shell --seed 2023189
(FPCore (x y)
:name "Logistic regression 2"
:precision binary64
:herbie-target
(if (<= x 0.0) (- (log (+ 1.0 (exp x))) (* x y)) (- (log (+ 1.0 (exp (- x)))) (* (- x) (- 1.0 y))))
(- (log (+ 1.0 (exp x))) (* x y)))