
(FPCore (x) :precision binary64 (let* ((t_0 (* (tan x) (tan x)))) (/ (- 1.0 t_0) (+ 1.0 t_0))))
double code(double x) {
double t_0 = tan(x) * tan(x);
return (1.0 - t_0) / (1.0 + t_0);
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = tan(x) * tan(x)
code = (1.0d0 - t_0) / (1.0d0 + t_0)
end function
public static double code(double x) {
double t_0 = Math.tan(x) * Math.tan(x);
return (1.0 - t_0) / (1.0 + t_0);
}
def code(x): t_0 = math.tan(x) * math.tan(x) return (1.0 - t_0) / (1.0 + t_0)
function code(x) t_0 = Float64(tan(x) * tan(x)) return Float64(Float64(1.0 - t_0) / Float64(1.0 + t_0)) end
function tmp = code(x) t_0 = tan(x) * tan(x); tmp = (1.0 - t_0) / (1.0 + t_0); end
code[x_] := Block[{t$95$0 = N[(N[Tan[x], $MachinePrecision] * N[Tan[x], $MachinePrecision]), $MachinePrecision]}, N[(N[(1.0 - t$95$0), $MachinePrecision] / N[(1.0 + t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan x \cdot \tan x\\
\frac{1 - t\_0}{1 + t\_0}
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (let* ((t_0 (* (tan x) (tan x)))) (/ (- 1.0 t_0) (+ 1.0 t_0))))
double code(double x) {
double t_0 = tan(x) * tan(x);
return (1.0 - t_0) / (1.0 + t_0);
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = tan(x) * tan(x)
code = (1.0d0 - t_0) / (1.0d0 + t_0)
end function
public static double code(double x) {
double t_0 = Math.tan(x) * Math.tan(x);
return (1.0 - t_0) / (1.0 + t_0);
}
def code(x): t_0 = math.tan(x) * math.tan(x) return (1.0 - t_0) / (1.0 + t_0)
function code(x) t_0 = Float64(tan(x) * tan(x)) return Float64(Float64(1.0 - t_0) / Float64(1.0 + t_0)) end
function tmp = code(x) t_0 = tan(x) * tan(x); tmp = (1.0 - t_0) / (1.0 + t_0); end
code[x_] := Block[{t$95$0 = N[(N[Tan[x], $MachinePrecision] * N[Tan[x], $MachinePrecision]), $MachinePrecision]}, N[(N[(1.0 - t$95$0), $MachinePrecision] / N[(1.0 + t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan x \cdot \tan x\\
\frac{1 - t\_0}{1 + t\_0}
\end{array}
\end{array}
(FPCore (x) :precision binary64 (/ (fma (tan x) (- (tan x)) 1.0) (- (pow (tan x) 2.0) -1.0)))
double code(double x) {
return fma(tan(x), -tan(x), 1.0) / (pow(tan(x), 2.0) - -1.0);
}
function code(x) return Float64(fma(tan(x), Float64(-tan(x)), 1.0) / Float64((tan(x) ^ 2.0) - -1.0)) end
code[x_] := N[(N[(N[Tan[x], $MachinePrecision] * (-N[Tan[x], $MachinePrecision]) + 1.0), $MachinePrecision] / N[(N[Power[N[Tan[x], $MachinePrecision], 2.0], $MachinePrecision] - -1.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\tan x, -\tan x, 1\right)}{{\tan x}^{2} - -1}
\end{array}
Initial program 99.4%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-rgt-neg-inN/A
lower-fma.f64N/A
lower-neg.f6499.5
Applied rewrites99.5%
lift-+.f64N/A
+-commutativeN/A
metadata-evalN/A
sub-negN/A
lower--.f6499.5
lift-*.f64N/A
pow2N/A
lift-pow.f6499.5
Applied rewrites99.5%
(FPCore (x) :precision binary64 (if (<= (* (tan x) (tan x)) 1.0) (/ 1.0 (- (pow (tan x) 2.0) -1.0)) (/ (- 1.0 (* x x)) (fma x x 1.0))))
double code(double x) {
double tmp;
if ((tan(x) * tan(x)) <= 1.0) {
tmp = 1.0 / (pow(tan(x), 2.0) - -1.0);
} else {
tmp = (1.0 - (x * x)) / fma(x, x, 1.0);
}
return tmp;
}
function code(x) tmp = 0.0 if (Float64(tan(x) * tan(x)) <= 1.0) tmp = Float64(1.0 / Float64((tan(x) ^ 2.0) - -1.0)); else tmp = Float64(Float64(1.0 - Float64(x * x)) / fma(x, x, 1.0)); end return tmp end
code[x_] := If[LessEqual[N[(N[Tan[x], $MachinePrecision] * N[Tan[x], $MachinePrecision]), $MachinePrecision], 1.0], N[(1.0 / N[(N[Power[N[Tan[x], $MachinePrecision], 2.0], $MachinePrecision] - -1.0), $MachinePrecision]), $MachinePrecision], N[(N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision] / N[(x * x + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\tan x \cdot \tan x \leq 1:\\
\;\;\;\;\frac{1}{{\tan x}^{2} - -1}\\
\mathbf{else}:\\
\;\;\;\;\frac{1 - x \cdot x}{\mathsf{fma}\left(x, x, 1\right)}\\
\end{array}
\end{array}
if (*.f64 (tan.f64 x) (tan.f64 x)) < 1Initial program 99.6%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-rgt-neg-inN/A
lower-fma.f64N/A
lower-neg.f6499.6
Applied rewrites99.6%
lift-+.f64N/A
+-commutativeN/A
metadata-evalN/A
sub-negN/A
lower--.f6499.6
lift-*.f64N/A
pow2N/A
lift-pow.f6499.6
Applied rewrites99.6%
Taylor expanded in x around 0
Applied rewrites72.8%
if 1 < (*.f64 (tan.f64 x) (tan.f64 x)) Initial program 99.1%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-rgt-neg-inN/A
lower-fma.f64N/A
lower-neg.f6499.1
Applied rewrites99.1%
lift-+.f64N/A
+-commutativeN/A
metadata-evalN/A
sub-negN/A
lower--.f6499.1
lift-*.f64N/A
pow2N/A
lift-pow.f6499.1
Applied rewrites99.1%
Taylor expanded in x around 0
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
unpow2N/A
lower-*.f644.3
Applied rewrites4.3%
Taylor expanded in x around 0
+-commutativeN/A
unpow2N/A
lower-fma.f6410.7
Applied rewrites10.7%
herbie shell --seed 2024226
(FPCore (x)
:name "Trigonometry B"
:precision binary64
(/ (- 1.0 (* (tan x) (tan x))) (+ 1.0 (* (tan x) (tan x)))))