
(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 9 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 -2.6)
(- 0.0 (* y x))
(+
(log 2.0)
(* x (+ (- 0.5 y) (* x (+ 0.125 (* -0.005208333333333333 (* x x)))))))))
double code(double x, double y) {
double tmp;
if (x <= -2.6) {
tmp = 0.0 - (y * x);
} else {
tmp = log(2.0) + (x * ((0.5 - y) + (x * (0.125 + (-0.005208333333333333 * (x * x))))));
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-2.6d0)) then
tmp = 0.0d0 - (y * x)
else
tmp = log(2.0d0) + (x * ((0.5d0 - y) + (x * (0.125d0 + ((-0.005208333333333333d0) * (x * x))))))
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -2.6) {
tmp = 0.0 - (y * x);
} else {
tmp = Math.log(2.0) + (x * ((0.5 - y) + (x * (0.125 + (-0.005208333333333333 * (x * x))))));
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -2.6: tmp = 0.0 - (y * x) else: tmp = math.log(2.0) + (x * ((0.5 - y) + (x * (0.125 + (-0.005208333333333333 * (x * x)))))) return tmp
function code(x, y) tmp = 0.0 if (x <= -2.6) tmp = Float64(0.0 - Float64(y * x)); else tmp = Float64(log(2.0) + Float64(x * Float64(Float64(0.5 - y) + Float64(x * Float64(0.125 + Float64(-0.005208333333333333 * Float64(x * x))))))); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -2.6) tmp = 0.0 - (y * x); else tmp = log(2.0) + (x * ((0.5 - y) + (x * (0.125 + (-0.005208333333333333 * (x * x)))))); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -2.6], N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(x * N[(N[(0.5 - y), $MachinePrecision] + N[(x * N[(0.125 + N[(-0.005208333333333333 * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.6:\\
\;\;\;\;0 - y \cdot x\\
\mathbf{else}:\\
\;\;\;\;\log 2 + x \cdot \left(\left(0.5 - y\right) + x \cdot \left(0.125 + -0.005208333333333333 \cdot \left(x \cdot x\right)\right)\right)\\
\end{array}
\end{array}
if x < -2.60000000000000009Initial program 99.4%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6499.4%
Simplified99.4%
Applied egg-rr99.4%
if -2.60000000000000009 < x Initial program 98.8%
Taylor expanded in x around 0
+-lowering-+.f64N/A
log-lowering-log.f64N/A
*-lowering-*.f64N/A
+-commutativeN/A
associate--l+N/A
+-commutativeN/A
+-lowering-+.f64N/A
--lowering--.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6499.4%
Simplified99.4%
Final simplification99.4%
(FPCore (x y) :precision binary64 (fma (- 0.0 y) x (log1p (exp x))))
double code(double x, double y) {
return fma((0.0 - y), x, log1p(exp(x)));
}
function code(x, y) return fma(Float64(0.0 - y), x, log1p(exp(x))) end
code[x_, y_] := N[(N[(0.0 - y), $MachinePrecision] * x + N[Log[1 + N[Exp[x], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(0 - y, x, \mathsf{log1p}\left(e^{x}\right)\right)
\end{array}
Initial program 99.0%
sub-negN/A
+-commutativeN/A
*-commutativeN/A
distribute-lft-neg-inN/A
fma-defineN/A
fma-lowering-fma.f64N/A
neg-sub0N/A
--lowering--.f64N/A
log1p-defineN/A
log1p-lowering-log1p.f64N/A
exp-lowering-exp.f6499.2%
Applied egg-rr99.2%
(FPCore (x y) :precision binary64 (- (log1p (exp x)) (* y x)))
double code(double x, double y) {
return log1p(exp(x)) - (y * x);
}
public static double code(double x, double y) {
return Math.log1p(Math.exp(x)) - (y * x);
}
def code(x, y): return math.log1p(math.exp(x)) - (y * x)
function code(x, y) return Float64(log1p(exp(x)) - Float64(y * x)) end
code[x_, y_] := N[(N[Log[1 + N[Exp[x], $MachinePrecision]], $MachinePrecision] - N[(y * x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{log1p}\left(e^{x}\right) - y \cdot x
\end{array}
Initial program 99.0%
--lowering--.f64N/A
log1p-defineN/A
log1p-lowering-log1p.f64N/A
exp-lowering-exp.f64N/A
*-lowering-*.f6499.2%
Simplified99.2%
Final simplification99.2%
(FPCore (x y) :precision binary64 (if (<= x -38.0) (- 0.0 (* y x)) (+ (log 2.0) (* x (+ 0.5 (- (* x 0.125) y))))))
double code(double x, double y) {
double tmp;
if (x <= -38.0) {
tmp = 0.0 - (y * x);
} else {
tmp = log(2.0) + (x * (0.5 + ((x * 0.125) - y)));
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-38.0d0)) then
tmp = 0.0d0 - (y * x)
else
tmp = log(2.0d0) + (x * (0.5d0 + ((x * 0.125d0) - y)))
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -38.0) {
tmp = 0.0 - (y * x);
} else {
tmp = Math.log(2.0) + (x * (0.5 + ((x * 0.125) - y)));
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -38.0: tmp = 0.0 - (y * x) else: tmp = math.log(2.0) + (x * (0.5 + ((x * 0.125) - y))) return tmp
function code(x, y) tmp = 0.0 if (x <= -38.0) tmp = Float64(0.0 - Float64(y * x)); else tmp = Float64(log(2.0) + Float64(x * Float64(0.5 + Float64(Float64(x * 0.125) - y)))); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -38.0) tmp = 0.0 - (y * x); else tmp = log(2.0) + (x * (0.5 + ((x * 0.125) - y))); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -38.0], N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(x * N[(0.5 + N[(N[(x * 0.125), $MachinePrecision] - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -38:\\
\;\;\;\;0 - y \cdot x\\
\mathbf{else}:\\
\;\;\;\;\log 2 + x \cdot \left(0.5 + \left(x \cdot 0.125 - y\right)\right)\\
\end{array}
\end{array}
if x < -38Initial program 99.4%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6499.4%
Simplified99.4%
Applied egg-rr99.4%
if -38 < x Initial program 98.8%
Taylor expanded in x around 0
+-lowering-+.f64N/A
log-lowering-log.f64N/A
*-lowering-*.f64N/A
associate--l+N/A
+-lowering-+.f64N/A
--lowering--.f64N/A
*-commutativeN/A
*-lowering-*.f6499.3%
Simplified99.3%
Final simplification99.4%
(FPCore (x y) :precision binary64 (if (<= x -1.38) (- 0.0 (* y x)) (+ (log 2.0) (* x (- 0.5 y)))))
double code(double x, double y) {
double tmp;
if (x <= -1.38) {
tmp = 0.0 - (y * x);
} else {
tmp = log(2.0) + (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 <= (-1.38d0)) then
tmp = 0.0d0 - (y * x)
else
tmp = log(2.0d0) + (x * (0.5d0 - y))
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -1.38) {
tmp = 0.0 - (y * x);
} else {
tmp = Math.log(2.0) + (x * (0.5 - y));
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -1.38: tmp = 0.0 - (y * x) else: tmp = math.log(2.0) + (x * (0.5 - y)) return tmp
function code(x, y) tmp = 0.0 if (x <= -1.38) tmp = Float64(0.0 - Float64(y * x)); else tmp = Float64(log(2.0) + Float64(x * Float64(0.5 - y))); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -1.38) tmp = 0.0 - (y * x); else tmp = log(2.0) + (x * (0.5 - y)); end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -1.38], N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision], N[(N[Log[2.0], $MachinePrecision] + N[(x * N[(0.5 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.38:\\
\;\;\;\;0 - y \cdot x\\
\mathbf{else}:\\
\;\;\;\;\log 2 + x \cdot \left(0.5 - y\right)\\
\end{array}
\end{array}
if x < -1.3799999999999999Initial program 99.4%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6499.4%
Simplified99.4%
Applied egg-rr99.4%
if -1.3799999999999999 < x Initial program 98.8%
Taylor expanded in x around 0
+-lowering-+.f64N/A
log-lowering-log.f64N/A
*-lowering-*.f64N/A
--lowering--.f6499.2%
Simplified99.2%
Final simplification99.3%
(FPCore (x y) :precision binary64 (let* ((t_0 (- 0.0 (* y x)))) (if (<= x -3.2e-76) t_0 (if (<= x 2.1e-35) (log 2.0) t_0))))
double code(double x, double y) {
double t_0 = 0.0 - (y * x);
double tmp;
if (x <= -3.2e-76) {
tmp = t_0;
} else if (x <= 2.1e-35) {
tmp = log(2.0);
} else {
tmp = t_0;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: t_0
real(8) :: tmp
t_0 = 0.0d0 - (y * x)
if (x <= (-3.2d-76)) then
tmp = t_0
else if (x <= 2.1d-35) then
tmp = log(2.0d0)
else
tmp = t_0
end if
code = tmp
end function
public static double code(double x, double y) {
double t_0 = 0.0 - (y * x);
double tmp;
if (x <= -3.2e-76) {
tmp = t_0;
} else if (x <= 2.1e-35) {
tmp = Math.log(2.0);
} else {
tmp = t_0;
}
return tmp;
}
def code(x, y): t_0 = 0.0 - (y * x) tmp = 0 if x <= -3.2e-76: tmp = t_0 elif x <= 2.1e-35: tmp = math.log(2.0) else: tmp = t_0 return tmp
function code(x, y) t_0 = Float64(0.0 - Float64(y * x)) tmp = 0.0 if (x <= -3.2e-76) tmp = t_0; elseif (x <= 2.1e-35) tmp = log(2.0); else tmp = t_0; end return tmp end
function tmp_2 = code(x, y) t_0 = 0.0 - (y * x); tmp = 0.0; if (x <= -3.2e-76) tmp = t_0; elseif (x <= 2.1e-35) tmp = log(2.0); else tmp = t_0; end tmp_2 = tmp; end
code[x_, y_] := Block[{t$95$0 = N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, -3.2e-76], t$95$0, If[LessEqual[x, 2.1e-35], N[Log[2.0], $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 0 - y \cdot x\\
\mathbf{if}\;x \leq -3.2 \cdot 10^{-76}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;x \leq 2.1 \cdot 10^{-35}:\\
\;\;\;\;\log 2\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if x < -3.1999999999999998e-76 or 2.1e-35 < x Initial program 97.9%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6487.9%
Simplified87.9%
Applied egg-rr87.9%
if -3.1999999999999998e-76 < x < 2.1e-35Initial program 100.0%
Taylor expanded in x around 0
log-lowering-log.f6483.1%
Simplified83.1%
Final simplification85.3%
(FPCore (x y) :precision binary64 (if (<= x -52.0) (- 0.0 (* y x)) (- (log1p 1.0) (* y x))))
double code(double x, double y) {
double tmp;
if (x <= -52.0) {
tmp = 0.0 - (y * x);
} else {
tmp = log1p(1.0) - (y * x);
}
return tmp;
}
public static double code(double x, double y) {
double tmp;
if (x <= -52.0) {
tmp = 0.0 - (y * x);
} else {
tmp = Math.log1p(1.0) - (y * x);
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -52.0: tmp = 0.0 - (y * x) else: tmp = math.log1p(1.0) - (y * x) return tmp
function code(x, y) tmp = 0.0 if (x <= -52.0) tmp = Float64(0.0 - Float64(y * x)); else tmp = Float64(log1p(1.0) - Float64(y * x)); end return tmp end
code[x_, y_] := If[LessEqual[x, -52.0], N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision], N[(N[Log[1 + 1.0], $MachinePrecision] - N[(y * x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -52:\\
\;\;\;\;0 - y \cdot x\\
\mathbf{else}:\\
\;\;\;\;\mathsf{log1p}\left(1\right) - y \cdot x\\
\end{array}
\end{array}
if x < -52Initial program 99.4%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6499.4%
Simplified99.4%
Applied egg-rr99.4%
if -52 < x Initial program 98.8%
--lowering--.f64N/A
log1p-defineN/A
log1p-lowering-log1p.f64N/A
exp-lowering-exp.f64N/A
*-lowering-*.f6498.8%
Simplified98.8%
Taylor expanded in x around 0
Simplified98.2%
Final simplification98.6%
(FPCore (x y) :precision binary64 (- 0.0 (* y x)))
double code(double x, double y) {
return 0.0 - (y * x);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = 0.0d0 - (y * x)
end function
public static double code(double x, double y) {
return 0.0 - (y * x);
}
def code(x, y): return 0.0 - (y * x)
function code(x, y) return Float64(0.0 - Float64(y * x)) end
function tmp = code(x, y) tmp = 0.0 - (y * x); end
code[x_, y_] := N[(0.0 - N[(y * x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0 - y \cdot x
\end{array}
Initial program 99.0%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6450.3%
Simplified50.3%
Applied egg-rr50.3%
Final simplification50.3%
(FPCore (x y) :precision binary64 (* y x))
double code(double x, double y) {
return y * x;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = y * x
end function
public static double code(double x, double y) {
return y * x;
}
def code(x, y): return y * x
function code(x, y) return Float64(y * x) end
function tmp = code(x, y) tmp = y * x; end
code[x_, y_] := N[(y * x), $MachinePrecision]
\begin{array}{l}
\\
y \cdot x
\end{array}
Initial program 99.0%
Taylor expanded in x around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
*-lowering-*.f6450.3%
Simplified50.3%
flip3--N/A
Applied egg-rr2.2%
(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 2024150
(FPCore (x y)
:name "Logistic regression 2"
:precision binary64
:alt
(! :herbie-platform default (if (<= x 0) (- (log (+ 1 (exp x))) (* x y)) (- (log (+ 1 (exp (- x)))) (* (- x) (- 1 y)))))
(- (log (+ 1.0 (exp x))) (* x y)))