
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
double code(double x, double y, double z) {
return ((x - ((y + 0.5) * log(y))) + y) - z;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = ((x - ((y + 0.5d0) * log(y))) + y) - z
end function
public static double code(double x, double y, double z) {
return ((x - ((y + 0.5) * Math.log(y))) + y) - z;
}
def code(x, y, z): return ((x - ((y + 0.5) * math.log(y))) + y) - z
function code(x, y, z) return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z) end
function tmp = code(x, y, z) tmp = ((x - ((y + 0.5) * log(y))) + y) - z; end
code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}
\\
\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
double code(double x, double y, double z) {
return ((x - ((y + 0.5) * log(y))) + y) - z;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = ((x - ((y + 0.5d0) * log(y))) + y) - z
end function
public static double code(double x, double y, double z) {
return ((x - ((y + 0.5) * Math.log(y))) + y) - z;
}
def code(x, y, z): return ((x - ((y + 0.5) * math.log(y))) + y) - z
function code(x, y, z) return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z) end
function tmp = code(x, y, z) tmp = ((x - ((y + 0.5) * log(y))) + y) - z; end
code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}
\\
\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z
\end{array}
(FPCore (x y z) :precision binary64 (+ x (fma (- (log y)) (+ 0.5 y) (- y z))))
double code(double x, double y, double z) {
return x + fma(-log(y), (0.5 + y), (y - z));
}
function code(x, y, z) return Float64(x + fma(Float64(-log(y)), Float64(0.5 + y), Float64(y - z))) end
code[x_, y_, z_] := N[(x + N[((-N[Log[y], $MachinePrecision]) * N[(0.5 + y), $MachinePrecision] + N[(y - z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \mathsf{fma}\left(-\log y, 0.5 + y, y - z\right)
\end{array}
Initial program 99.9%
lift--.f64N/A
lift-+.f64N/A
associate--l+N/A
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
associate-+l+N/A
lower-+.f64N/A
distribute-lft-neg-outN/A
*-commutativeN/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lower-neg.f64N/A
lift-+.f64N/A
+-commutativeN/A
lower-+.f64N/A
lower--.f6499.9
Applied rewrites99.9%
(FPCore (x y z)
:precision binary64
(if (<= y 1.1e+93)
(- (fma -0.5 (log y) x) z)
(if (<= y 1.55e+131)
(- y (fma (+ 0.5 y) (log y) z))
(+ x (* (- 1.0 (log y)) y)))))
double code(double x, double y, double z) {
double tmp;
if (y <= 1.1e+93) {
tmp = fma(-0.5, log(y), x) - z;
} else if (y <= 1.55e+131) {
tmp = y - fma((0.5 + y), log(y), z);
} else {
tmp = x + ((1.0 - log(y)) * y);
}
return tmp;
}
function code(x, y, z) tmp = 0.0 if (y <= 1.1e+93) tmp = Float64(fma(-0.5, log(y), x) - z); elseif (y <= 1.55e+131) tmp = Float64(y - fma(Float64(0.5 + y), log(y), z)); else tmp = Float64(x + Float64(Float64(1.0 - log(y)) * y)); end return tmp end
code[x_, y_, z_] := If[LessEqual[y, 1.1e+93], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], If[LessEqual[y, 1.55e+131], N[(y - N[(N[(0.5 + y), $MachinePrecision] * N[Log[y], $MachinePrecision] + z), $MachinePrecision]), $MachinePrecision], N[(x + N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq 1.1 \cdot 10^{+93}:\\
\;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
\mathbf{elif}\;y \leq 1.55 \cdot 10^{+131}:\\
\;\;\;\;y - \mathsf{fma}\left(0.5 + y, \log y, z\right)\\
\mathbf{else}:\\
\;\;\;\;x + \left(1 - \log y\right) \cdot y\\
\end{array}
\end{array}
if y < 1.10000000000000011e93Initial program 99.9%
Taylor expanded in y around 0
+-commutativeN/A
associate--r+N/A
lower--.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
lower-log.f6496.8
Applied rewrites96.8%
if 1.10000000000000011e93 < y < 1.55000000000000008e131Initial program 99.7%
Taylor expanded in x around 0
lower--.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-+.f64N/A
lower-log.f6493.6
Applied rewrites93.6%
if 1.55000000000000008e131 < y Initial program 99.6%
lift--.f64N/A
lift-+.f64N/A
associate--l+N/A
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
associate-+l+N/A
lower-+.f64N/A
distribute-lft-neg-outN/A
*-commutativeN/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lower-neg.f64N/A
lift-+.f64N/A
+-commutativeN/A
lower-+.f64N/A
lower--.f6499.8
Applied rewrites99.8%
Taylor expanded in y around inf
*-commutativeN/A
lower-*.f64N/A
*-lft-identityN/A
fp-cancel-sign-sub-invN/A
metadata-evalN/A
mul-1-negN/A
log-recN/A
remove-double-negN/A
lower--.f64N/A
lower-log.f6488.6
Applied rewrites88.6%
(FPCore (x y z) :precision binary64 (if (<= y 2.6e-25) (- (fma -0.5 (log y) x) z) (- (+ (- x (* (log y) y)) y) z)))
double code(double x, double y, double z) {
double tmp;
if (y <= 2.6e-25) {
tmp = fma(-0.5, log(y), x) - z;
} else {
tmp = ((x - (log(y) * y)) + y) - z;
}
return tmp;
}
function code(x, y, z) tmp = 0.0 if (y <= 2.6e-25) tmp = Float64(fma(-0.5, log(y), x) - z); else tmp = Float64(Float64(Float64(x - Float64(log(y) * y)) + y) - z); end return tmp end
code[x_, y_, z_] := If[LessEqual[y, 2.6e-25], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], N[(N[(N[(x - N[(N[Log[y], $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq 2.6 \cdot 10^{-25}:\\
\;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
\mathbf{else}:\\
\;\;\;\;\left(\left(x - \log y \cdot y\right) + y\right) - z\\
\end{array}
\end{array}
if y < 2.6e-25Initial program 100.0%
Taylor expanded in y around 0
+-commutativeN/A
associate--r+N/A
lower--.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
lower-log.f64100.0
Applied rewrites100.0%
if 2.6e-25 < y Initial program 99.7%
Taylor expanded in y around inf
*-commutativeN/A
associate-*r*N/A
mul-1-negN/A
log-recN/A
remove-double-negN/A
lower-*.f64N/A
lower-log.f6499.4
Applied rewrites99.4%
(FPCore (x y z) :precision binary64 (if (<= y 9.5e+114) (- (fma -0.5 (log y) x) z) (+ x (* (- 1.0 (log y)) y))))
double code(double x, double y, double z) {
double tmp;
if (y <= 9.5e+114) {
tmp = fma(-0.5, log(y), x) - z;
} else {
tmp = x + ((1.0 - log(y)) * y);
}
return tmp;
}
function code(x, y, z) tmp = 0.0 if (y <= 9.5e+114) tmp = Float64(fma(-0.5, log(y), x) - z); else tmp = Float64(x + Float64(Float64(1.0 - log(y)) * y)); end return tmp end
code[x_, y_, z_] := If[LessEqual[y, 9.5e+114], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], N[(x + N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq 9.5 \cdot 10^{+114}:\\
\;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
\mathbf{else}:\\
\;\;\;\;x + \left(1 - \log y\right) \cdot y\\
\end{array}
\end{array}
if y < 9.5000000000000001e114Initial program 99.9%
Taylor expanded in y around 0
+-commutativeN/A
associate--r+N/A
lower--.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
lower-log.f6495.9
Applied rewrites95.9%
if 9.5000000000000001e114 < y Initial program 99.6%
lift--.f64N/A
lift-+.f64N/A
associate--l+N/A
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
associate-+l+N/A
lower-+.f64N/A
distribute-lft-neg-outN/A
*-commutativeN/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lower-neg.f64N/A
lift-+.f64N/A
+-commutativeN/A
lower-+.f64N/A
lower--.f6499.7
Applied rewrites99.7%
Taylor expanded in y around inf
*-commutativeN/A
lower-*.f64N/A
*-lft-identityN/A
fp-cancel-sign-sub-invN/A
metadata-evalN/A
mul-1-negN/A
log-recN/A
remove-double-negN/A
lower--.f64N/A
lower-log.f6485.8
Applied rewrites85.8%
(FPCore (x y z) :precision binary64 (if (<= y 1.3e+115) (- (fma -0.5 (log y) x) z) (* (- 1.0 (log y)) y)))
double code(double x, double y, double z) {
double tmp;
if (y <= 1.3e+115) {
tmp = fma(-0.5, log(y), x) - z;
} else {
tmp = (1.0 - log(y)) * y;
}
return tmp;
}
function code(x, y, z) tmp = 0.0 if (y <= 1.3e+115) tmp = Float64(fma(-0.5, log(y), x) - z); else tmp = Float64(Float64(1.0 - log(y)) * y); end return tmp end
code[x_, y_, z_] := If[LessEqual[y, 1.3e+115], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq 1.3 \cdot 10^{+115}:\\
\;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
\mathbf{else}:\\
\;\;\;\;\left(1 - \log y\right) \cdot y\\
\end{array}
\end{array}
if y < 1.3e115Initial program 99.9%
Taylor expanded in y around 0
+-commutativeN/A
associate--r+N/A
lower--.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
lower-log.f6495.9
Applied rewrites95.9%
if 1.3e115 < y Initial program 99.6%
Taylor expanded in y around inf
*-commutativeN/A
mul-1-negN/A
log-recN/A
remove-double-negN/A
lower-*.f64N/A
lower--.f64N/A
lower-log.f6464.2
Applied rewrites64.2%
(FPCore (x y z) :precision binary64 (if (<= y 9.5e+114) (- (* -0.5 (log y)) z) (* (- 1.0 (log y)) y)))
double code(double x, double y, double z) {
double tmp;
if (y <= 9.5e+114) {
tmp = (-0.5 * log(y)) - z;
} else {
tmp = (1.0 - log(y)) * y;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if (y <= 9.5d+114) then
tmp = ((-0.5d0) * log(y)) - z
else
tmp = (1.0d0 - log(y)) * y
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double tmp;
if (y <= 9.5e+114) {
tmp = (-0.5 * Math.log(y)) - z;
} else {
tmp = (1.0 - Math.log(y)) * y;
}
return tmp;
}
def code(x, y, z): tmp = 0 if y <= 9.5e+114: tmp = (-0.5 * math.log(y)) - z else: tmp = (1.0 - math.log(y)) * y return tmp
function code(x, y, z) tmp = 0.0 if (y <= 9.5e+114) tmp = Float64(Float64(-0.5 * log(y)) - z); else tmp = Float64(Float64(1.0 - log(y)) * y); end return tmp end
function tmp_2 = code(x, y, z) tmp = 0.0; if (y <= 9.5e+114) tmp = (-0.5 * log(y)) - z; else tmp = (1.0 - log(y)) * y; end tmp_2 = tmp; end
code[x_, y_, z_] := If[LessEqual[y, 9.5e+114], N[(N[(-0.5 * N[Log[y], $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision], N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq 9.5 \cdot 10^{+114}:\\
\;\;\;\;-0.5 \cdot \log y - z\\
\mathbf{else}:\\
\;\;\;\;\left(1 - \log y\right) \cdot y\\
\end{array}
\end{array}
if y < 9.5000000000000001e114Initial program 99.9%
Taylor expanded in x around 0
lower--.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-+.f64N/A
lower-log.f6469.5
Applied rewrites69.5%
Taylor expanded in y around 0
Applied rewrites65.4%
if 9.5000000000000001e114 < y Initial program 99.6%
Taylor expanded in y around inf
*-commutativeN/A
mul-1-negN/A
log-recN/A
remove-double-negN/A
lower-*.f64N/A
lower--.f64N/A
lower-log.f6464.2
Applied rewrites64.2%
Final simplification65.1%
(FPCore (x y z) :precision binary64 (- (* -0.5 (log y)) z))
double code(double x, double y, double z) {
return (-0.5 * log(y)) - z;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = ((-0.5d0) * log(y)) - z
end function
public static double code(double x, double y, double z) {
return (-0.5 * Math.log(y)) - z;
}
def code(x, y, z): return (-0.5 * math.log(y)) - z
function code(x, y, z) return Float64(Float64(-0.5 * log(y)) - z) end
function tmp = code(x, y, z) tmp = (-0.5 * log(y)) - z; end
code[x_, y_, z_] := N[(N[(-0.5 * N[Log[y], $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \log y - z
\end{array}
Initial program 99.9%
Taylor expanded in x around 0
lower--.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-+.f64N/A
lower-log.f6472.0
Applied rewrites72.0%
Taylor expanded in y around 0
Applied rewrites49.7%
Final simplification49.7%
(FPCore (x y z) :precision binary64 (- z))
double code(double x, double y, double z) {
return -z;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = -z
end function
public static double code(double x, double y, double z) {
return -z;
}
def code(x, y, z): return -z
function code(x, y, z) return Float64(-z) end
function tmp = code(x, y, z) tmp = -z; end
code[x_, y_, z_] := (-z)
\begin{array}{l}
\\
-z
\end{array}
Initial program 99.9%
Taylor expanded in z around inf
mul-1-negN/A
lower-neg.f6435.1
Applied rewrites35.1%
(FPCore (x y z) :precision binary64 (- (- (+ y x) z) (* (+ y 0.5) (log y))))
double code(double x, double y, double z) {
return ((y + x) - z) - ((y + 0.5) * log(y));
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = ((y + x) - z) - ((y + 0.5d0) * log(y))
end function
public static double code(double x, double y, double z) {
return ((y + x) - z) - ((y + 0.5) * Math.log(y));
}
def code(x, y, z): return ((y + x) - z) - ((y + 0.5) * math.log(y))
function code(x, y, z) return Float64(Float64(Float64(y + x) - z) - Float64(Float64(y + 0.5) * log(y))) end
function tmp = code(x, y, z) tmp = ((y + x) - z) - ((y + 0.5) * log(y)); end
code[x_, y_, z_] := N[(N[(N[(y + x), $MachinePrecision] - z), $MachinePrecision] - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\left(y + x\right) - z\right) - \left(y + 0.5\right) \cdot \log y
\end{array}
herbie shell --seed 2024339
(FPCore (x y z)
:name "Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2"
:precision binary64
:alt
(! :herbie-platform default (- (- (+ y x) z) (* (+ y 1/2) (log y))))
(- (+ (- x (* (+ y 0.5) (log y))) y) z))