
(FPCore (x) :precision binary64 (log (+ (/ 1.0 x) (/ (sqrt (- 1.0 (* x x))) x))))
double code(double x) {
return log(((1.0 / x) + (sqrt((1.0 - (x * x))) / x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = log(((1.0d0 / x) + (sqrt((1.0d0 - (x * x))) / x)))
end function
public static double code(double x) {
return Math.log(((1.0 / x) + (Math.sqrt((1.0 - (x * x))) / x)));
}
def code(x): return math.log(((1.0 / x) + (math.sqrt((1.0 - (x * x))) / x)))
function code(x) return log(Float64(Float64(1.0 / x) + Float64(sqrt(Float64(1.0 - Float64(x * x))) / x))) end
function tmp = code(x) tmp = log(((1.0 / x) + (sqrt((1.0 - (x * x))) / x))); end
code[x_] := N[Log[N[(N[(1.0 / x), $MachinePrecision] + N[(N[Sqrt[N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (log (+ (/ 1.0 x) (/ (sqrt (- 1.0 (* x x))) x))))
double code(double x) {
return log(((1.0 / x) + (sqrt((1.0 - (x * x))) / x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = log(((1.0d0 / x) + (sqrt((1.0d0 - (x * x))) / x)))
end function
public static double code(double x) {
return Math.log(((1.0 / x) + (Math.sqrt((1.0 - (x * x))) / x)));
}
def code(x): return math.log(((1.0 / x) + (math.sqrt((1.0 - (x * x))) / x)))
function code(x) return log(Float64(Float64(1.0 / x) + Float64(sqrt(Float64(1.0 - Float64(x * x))) / x))) end
function tmp = code(x) tmp = log(((1.0 / x) + (sqrt((1.0 - (x * x))) / x))); end
code[x_] := N[Log[N[(N[(1.0 / x), $MachinePrecision] + N[(N[Sqrt[N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\right)
\end{array}
(FPCore (x) :precision binary64 (log (/ (+ 1.0 (sqrt (- 1.0 (* x x)))) x)))
double code(double x) {
return log(((1.0 + sqrt((1.0 - (x * x)))) / x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = log(((1.0d0 + sqrt((1.0d0 - (x * x)))) / x))
end function
public static double code(double x) {
return Math.log(((1.0 + Math.sqrt((1.0 - (x * x)))) / x));
}
def code(x): return math.log(((1.0 + math.sqrt((1.0 - (x * x)))) / x))
function code(x) return log(Float64(Float64(1.0 + sqrt(Float64(1.0 - Float64(x * x)))) / x)) end
function tmp = code(x) tmp = log(((1.0 + sqrt((1.0 - (x * x)))) / x)); end
code[x_] := N[Log[N[(N[(1.0 + N[Sqrt[N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(\frac{1 + \sqrt{1 - x \cdot x}}{x}\right)
\end{array}
Initial program 100.0%
lift-+.f64N/A
lift-/.f64N/A
div-invN/A
lift-/.f64N/A
distribute-rgt1-inN/A
lift-/.f64N/A
un-div-invN/A
lower-/.f64N/A
+-commutativeN/A
lower-+.f64100.0
Applied rewrites100.0%
(FPCore (x) :precision binary64 (log (fma x -0.5 (/ 2.0 x))))
double code(double x) {
return log(fma(x, -0.5, (2.0 / x)));
}
function code(x) return log(fma(x, -0.5, Float64(2.0 / x))) end
code[x_] := N[Log[N[(x * -0.5 + N[(2.0 / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(\mathsf{fma}\left(x, -0.5, \frac{2}{x}\right)\right)
\end{array}
Initial program 100.0%
Taylor expanded in x around 0
lower-/.f64N/A
+-commutativeN/A
unpow2N/A
associate-*r*N/A
*-commutativeN/A
metadata-evalN/A
distribute-lft-neg-inN/A
*-commutativeN/A
lower-fma.f64N/A
distribute-rgt-neg-inN/A
metadata-evalN/A
lower-*.f64100.0
Applied rewrites100.0%
Taylor expanded in x around inf
Applied rewrites0.0%
Taylor expanded in x around inf
Applied rewrites100.0%
(FPCore (x) :precision binary64 (log (/ 2.0 x)))
double code(double x) {
return log((2.0 / x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = log((2.0d0 / x))
end function
public static double code(double x) {
return Math.log((2.0 / x));
}
def code(x): return math.log((2.0 / x))
function code(x) return log(Float64(2.0 / x)) end
function tmp = code(x) tmp = log((2.0 / x)); end
code[x_] := N[Log[N[(2.0 / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(\frac{2}{x}\right)
\end{array}
Initial program 100.0%
Taylor expanded in x around 0
lower-/.f6499.6
Applied rewrites99.6%
(FPCore (x) :precision binary64 (log (* x -0.5)))
double code(double x) {
return log((x * -0.5));
}
real(8) function code(x)
real(8), intent (in) :: x
code = log((x * (-0.5d0)))
end function
public static double code(double x) {
return Math.log((x * -0.5));
}
def code(x): return math.log((x * -0.5))
function code(x) return log(Float64(x * -0.5)) end
function tmp = code(x) tmp = log((x * -0.5)); end
code[x_] := N[Log[N[(x * -0.5), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\log \left(x \cdot -0.5\right)
\end{array}
Initial program 100.0%
Taylor expanded in x around 0
lower-/.f64N/A
+-commutativeN/A
unpow2N/A
associate-*r*N/A
*-commutativeN/A
metadata-evalN/A
distribute-lft-neg-inN/A
*-commutativeN/A
lower-fma.f64N/A
distribute-rgt-neg-inN/A
metadata-evalN/A
lower-*.f64100.0
Applied rewrites100.0%
Taylor expanded in x around inf
Applied rewrites0.0%
herbie shell --seed 2024223
(FPCore (x)
:name "Hyperbolic arc-(co)secant"
:precision binary64
(log (+ (/ 1.0 x) (/ (sqrt (- 1.0 (* x x))) x))))