
(FPCore (x) :precision binary64 (+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (- x 1.0))))
double code(double x) {
return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((1.0d0 / (x + 1.0d0)) - (2.0d0 / x)) + (1.0d0 / (x - 1.0d0))
end function
public static double code(double x) {
return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0));
}
def code(x): return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0))
function code(x) return Float64(Float64(Float64(1.0 / Float64(x + 1.0)) - Float64(2.0 / x)) + Float64(1.0 / Float64(x - 1.0))) end
function tmp = code(x) tmp = ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0)); end
code[x_] := N[(N[(N[(1.0 / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(x - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (- x 1.0))))
double code(double x) {
return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((1.0d0 / (x + 1.0d0)) - (2.0d0 / x)) + (1.0d0 / (x - 1.0d0))
end function
public static double code(double x) {
return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0));
}
def code(x): return ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0))
function code(x) return Float64(Float64(Float64(1.0 / Float64(x + 1.0)) - Float64(2.0 / x)) + Float64(1.0 / Float64(x - 1.0))) end
function tmp = code(x) tmp = ((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x - 1.0)); end
code[x_] := N[(N[(N[(1.0 / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(x - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}
\end{array}
(FPCore (x) :precision binary64 (* (fma (fma 2.0 (pow x -2.0) 2.0) (pow x -2.0) 2.0) (pow x -3.0)))
double code(double x) {
return fma(fma(2.0, pow(x, -2.0), 2.0), pow(x, -2.0), 2.0) * pow(x, -3.0);
}
function code(x) return Float64(fma(fma(2.0, (x ^ -2.0), 2.0), (x ^ -2.0), 2.0) * (x ^ -3.0)) end
code[x_] := N[(N[(N[(2.0 * N[Power[x, -2.0], $MachinePrecision] + 2.0), $MachinePrecision] * N[Power[x, -2.0], $MachinePrecision] + 2.0), $MachinePrecision] * N[Power[x, -3.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(2, {x}^{-2}, 2\right), {x}^{-2}, 2\right) \cdot {x}^{-3}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
Taylor expanded in x around -inf 99.5%
associate-*r/99.5%
Simplified99.5%
div-inv99.5%
+-commutative99.5%
div-inv99.5%
fma-define99.5%
+-commutative99.5%
div-inv99.5%
fma-define99.5%
pow-flip99.5%
metadata-eval99.5%
pow-flip99.5%
metadata-eval99.5%
pow-flip99.8%
metadata-eval99.8%
Applied egg-rr99.8%
(FPCore (x) :precision binary64 (* (/ -2.0 x) (/ 1.0 (* (+ x -1.0) (- -1.0 x)))))
double code(double x) {
return (-2.0 / x) * (1.0 / ((x + -1.0) * (-1.0 - x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((-2.0d0) / x) * (1.0d0 / ((x + (-1.0d0)) * ((-1.0d0) - x)))
end function
public static double code(double x) {
return (-2.0 / x) * (1.0 / ((x + -1.0) * (-1.0 - x)));
}
def code(x): return (-2.0 / x) * (1.0 / ((x + -1.0) * (-1.0 - x)))
function code(x) return Float64(Float64(-2.0 / x) * Float64(1.0 / Float64(Float64(x + -1.0) * Float64(-1.0 - x)))) end
function tmp = code(x) tmp = (-2.0 / x) * (1.0 / ((x + -1.0) * (-1.0 - x))); end
code[x_] := N[(N[(-2.0 / x), $MachinePrecision] * N[(1.0 / N[(N[(x + -1.0), $MachinePrecision] * N[(-1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2}{x} \cdot \frac{1}{\left(x + -1\right) \cdot \left(-1 - x\right)}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
+-commutative72.2%
associate-+l-72.2%
Applied egg-rr72.2%
frac-sub17.6%
frac-sub18.8%
*-un-lft-identity18.8%
Applied egg-rr18.8%
*-commutative18.8%
*-rgt-identity18.8%
associate--l+18.8%
sub-neg18.8%
associate--r+18.8%
metadata-eval18.8%
neg-sub018.8%
remove-double-neg18.8%
*-commutative18.8%
Simplified18.8%
Taylor expanded in x around 0 99.6%
associate-/r*99.8%
div-inv99.8%
Applied egg-rr99.8%
(FPCore (x) :precision binary64 (/ -2.0 (* x (* (+ x -1.0) (- -1.0 x)))))
double code(double x) {
return -2.0 / (x * ((x + -1.0) * (-1.0 - x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-2.0d0) / (x * ((x + (-1.0d0)) * ((-1.0d0) - x)))
end function
public static double code(double x) {
return -2.0 / (x * ((x + -1.0) * (-1.0 - x)));
}
def code(x): return -2.0 / (x * ((x + -1.0) * (-1.0 - x)))
function code(x) return Float64(-2.0 / Float64(x * Float64(Float64(x + -1.0) * Float64(-1.0 - x)))) end
function tmp = code(x) tmp = -2.0 / (x * ((x + -1.0) * (-1.0 - x))); end
code[x_] := N[(-2.0 / N[(x * N[(N[(x + -1.0), $MachinePrecision] * N[(-1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2}{x \cdot \left(\left(x + -1\right) \cdot \left(-1 - x\right)\right)}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
+-commutative72.2%
associate-+l-72.2%
Applied egg-rr72.2%
frac-sub17.6%
frac-sub18.8%
*-un-lft-identity18.8%
Applied egg-rr18.8%
*-commutative18.8%
*-rgt-identity18.8%
associate--l+18.8%
sub-neg18.8%
associate--r+18.8%
metadata-eval18.8%
neg-sub018.8%
remove-double-neg18.8%
*-commutative18.8%
Simplified18.8%
Taylor expanded in x around 0 99.6%
(FPCore (x) :precision binary64 (+ (/ 1.0 (+ x -1.0)) (/ -1.0 x)))
double code(double x) {
return (1.0 / (x + -1.0)) + (-1.0 / x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = (1.0d0 / (x + (-1.0d0))) + ((-1.0d0) / x)
end function
public static double code(double x) {
return (1.0 / (x + -1.0)) + (-1.0 / x);
}
def code(x): return (1.0 / (x + -1.0)) + (-1.0 / x)
function code(x) return Float64(Float64(1.0 / Float64(x + -1.0)) + Float64(-1.0 / x)) end
function tmp = code(x) tmp = (1.0 / (x + -1.0)) + (-1.0 / x); end
code[x_] := N[(N[(1.0 / N[(x + -1.0), $MachinePrecision]), $MachinePrecision] + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{x + -1} + \frac{-1}{x}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
Taylor expanded in x around inf 71.4%
(FPCore (x) :precision binary64 (- (/ -2.0 x) (/ -2.0 x)))
double code(double x) {
return (-2.0 / x) - (-2.0 / x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((-2.0d0) / x) - ((-2.0d0) / x)
end function
public static double code(double x) {
return (-2.0 / x) - (-2.0 / x);
}
def code(x): return (-2.0 / x) - (-2.0 / x)
function code(x) return Float64(Float64(-2.0 / x) - Float64(-2.0 / x)) end
function tmp = code(x) tmp = (-2.0 / x) - (-2.0 / x); end
code[x_] := N[(N[(-2.0 / x), $MachinePrecision] - N[(-2.0 / x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2}{x} - \frac{-2}{x}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
+-commutative72.2%
associate-+l-72.2%
Applied egg-rr72.2%
frac-sub17.6%
*-un-lft-identity17.6%
Applied egg-rr17.6%
*-rgt-identity17.6%
associate--l+17.6%
sub-neg17.6%
associate--r+17.6%
metadata-eval17.6%
neg-sub017.6%
remove-double-neg17.6%
*-commutative17.6%
Simplified17.6%
Taylor expanded in x around inf 71.2%
(FPCore (x) :precision binary64 (/ -1.0 x))
double code(double x) {
return -1.0 / x;
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-1.0d0) / x
end function
public static double code(double x) {
return -1.0 / x;
}
def code(x): return -1.0 / x
function code(x) return Float64(-1.0 / x) end
function tmp = code(x) tmp = -1.0 / x; end
code[x_] := N[(-1.0 / x), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{x}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
Taylor expanded in x around inf 71.4%
Taylor expanded in x around 0 5.2%
(FPCore (x) :precision binary64 (/ -2.0 x))
double code(double x) {
return -2.0 / x;
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-2.0d0) / x
end function
public static double code(double x) {
return -2.0 / x;
}
def code(x): return -2.0 / x
function code(x) return Float64(-2.0 / x) end
function tmp = code(x) tmp = -2.0 / x; end
code[x_] := N[(-2.0 / x), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2}{x}
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
Taylor expanded in x around 0 5.2%
(FPCore (x) :precision binary64 1.0)
double code(double x) {
return 1.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0
end function
public static double code(double x) {
return 1.0;
}
def code(x): return 1.0
function code(x) return 1.0 end
function tmp = code(x) tmp = 1.0; end
code[x_] := 1.0
\begin{array}{l}
\\
1
\end{array}
Initial program 72.2%
+-commutative72.2%
associate-+r-72.2%
sub-neg72.2%
remove-double-neg72.2%
neg-sub072.2%
associate-+l-72.2%
neg-sub072.2%
distribute-neg-frac272.2%
distribute-frac-neg272.2%
associate-+r+72.2%
+-commutative72.2%
remove-double-neg72.2%
distribute-neg-frac272.2%
sub0-neg72.2%
associate-+l-72.2%
neg-sub072.2%
Simplified72.2%
Taylor expanded in x around 0 3.3%
Taylor expanded in x around inf 3.3%
(FPCore (x) :precision binary64 (/ 2.0 (* x (- (* x x) 1.0))))
double code(double x) {
return 2.0 / (x * ((x * x) - 1.0));
}
real(8) function code(x)
real(8), intent (in) :: x
code = 2.0d0 / (x * ((x * x) - 1.0d0))
end function
public static double code(double x) {
return 2.0 / (x * ((x * x) - 1.0));
}
def code(x): return 2.0 / (x * ((x * x) - 1.0))
function code(x) return Float64(2.0 / Float64(x * Float64(Float64(x * x) - 1.0))) end
function tmp = code(x) tmp = 2.0 / (x * ((x * x) - 1.0)); end
code[x_] := N[(2.0 / N[(x * N[(N[(x * x), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{2}{x \cdot \left(x \cdot x - 1\right)}
\end{array}
herbie shell --seed 2024103
(FPCore (x)
:name "3frac (problem 3.3.3)"
:precision binary64
:pre (> (fabs x) 1.0)
:alt
(/ 2.0 (* x (- (* x x) 1.0)))
(+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (- x 1.0))))