
(FPCore (x) :precision binary64 (+ (/ 1.0 (- x 1.0)) (/ x (+ x 1.0))))
double code(double x) {
return (1.0 / (x - 1.0)) + (x / (x + 1.0));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (1.0d0 / (x - 1.0d0)) + (x / (x + 1.0d0))
end function
public static double code(double x) {
return (1.0 / (x - 1.0)) + (x / (x + 1.0));
}
def code(x): return (1.0 / (x - 1.0)) + (x / (x + 1.0))
function code(x) return Float64(Float64(1.0 / Float64(x - 1.0)) + Float64(x / Float64(x + 1.0))) end
function tmp = code(x) tmp = (1.0 / (x - 1.0)) + (x / (x + 1.0)); end
code[x_] := N[(N[(1.0 / N[(x - 1.0), $MachinePrecision]), $MachinePrecision] + N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{x - 1} + \frac{x}{x + 1}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (+ (/ 1.0 (- x 1.0)) (/ x (+ x 1.0))))
double code(double x) {
return (1.0 / (x - 1.0)) + (x / (x + 1.0));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (1.0d0 / (x - 1.0d0)) + (x / (x + 1.0d0))
end function
public static double code(double x) {
return (1.0 / (x - 1.0)) + (x / (x + 1.0));
}
def code(x): return (1.0 / (x - 1.0)) + (x / (x + 1.0))
function code(x) return Float64(Float64(1.0 / Float64(x - 1.0)) + Float64(x / Float64(x + 1.0))) end
function tmp = code(x) tmp = (1.0 / (x - 1.0)) + (x / (x + 1.0)); end
code[x_] := N[(N[(1.0 / N[(x - 1.0), $MachinePrecision]), $MachinePrecision] + N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{x - 1} + \frac{x}{x + 1}
\end{array}
(FPCore (x) :precision binary64 (/ (- (/ -1.0 x) x) (- (/ 1.0 x) x)))
double code(double x) {
return ((-1.0 / x) - x) / ((1.0 / x) - x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = (((-1.0d0) / x) - x) / ((1.0d0 / x) - x)
end function
public static double code(double x) {
return ((-1.0 / x) - x) / ((1.0 / x) - x);
}
def code(x): return ((-1.0 / x) - x) / ((1.0 / x) - x)
function code(x) return Float64(Float64(Float64(-1.0 / x) - x) / Float64(Float64(1.0 / x) - x)) end
function tmp = code(x) tmp = ((-1.0 / x) - x) / ((1.0 / x) - x); end
code[x_] := N[(N[(N[(-1.0 / x), $MachinePrecision] - x), $MachinePrecision] / N[(N[(1.0 / x), $MachinePrecision] - x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{-1}{x} - x}{\frac{1}{x} - x}
\end{array}
Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/76.1%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.8%
Applied egg-rr99.8%
Simplified100.0%
Taylor expanded in x around 0 100.0%
neg-mul-1100.0%
+-commutative100.0%
unsub-neg100.0%
Simplified100.0%
Final simplification100.0%
(FPCore (x) :precision binary64 (if (or (<= x -1.75) (not (<= x 1.0))) (/ (- (/ -1.0 x) x) (- x)) (+ (/ x (+ x 1.0)) (- -1.0 x))))
double code(double x) {
double tmp;
if ((x <= -1.75) || !(x <= 1.0)) {
tmp = ((-1.0 / x) - x) / -x;
} else {
tmp = (x / (x + 1.0)) + (-1.0 - x);
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: tmp
if ((x <= (-1.75d0)) .or. (.not. (x <= 1.0d0))) then
tmp = (((-1.0d0) / x) - x) / -x
else
tmp = (x / (x + 1.0d0)) + ((-1.0d0) - x)
end if
code = tmp
end function
public static double code(double x) {
double tmp;
if ((x <= -1.75) || !(x <= 1.0)) {
tmp = ((-1.0 / x) - x) / -x;
} else {
tmp = (x / (x + 1.0)) + (-1.0 - x);
}
return tmp;
}
def code(x): tmp = 0 if (x <= -1.75) or not (x <= 1.0): tmp = ((-1.0 / x) - x) / -x else: tmp = (x / (x + 1.0)) + (-1.0 - x) return tmp
function code(x) tmp = 0.0 if ((x <= -1.75) || !(x <= 1.0)) tmp = Float64(Float64(Float64(-1.0 / x) - x) / Float64(-x)); else tmp = Float64(Float64(x / Float64(x + 1.0)) + Float64(-1.0 - x)); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if ((x <= -1.75) || ~((x <= 1.0))) tmp = ((-1.0 / x) - x) / -x; else tmp = (x / (x + 1.0)) + (-1.0 - x); end tmp_2 = tmp; end
code[x_] := If[Or[LessEqual[x, -1.75], N[Not[LessEqual[x, 1.0]], $MachinePrecision]], N[(N[(N[(-1.0 / x), $MachinePrecision] - x), $MachinePrecision] / (-x)), $MachinePrecision], N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(-1.0 - x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.75 \lor \neg \left(x \leq 1\right):\\
\;\;\;\;\frac{\frac{-1}{x} - x}{-x}\\
\mathbf{else}:\\
\;\;\;\;\frac{x}{x + 1} + \left(-1 - x\right)\\
\end{array}
\end{array}
if x < -1.75 or 1 < x Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/53.3%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.7%
Applied egg-rr99.7%
Simplified100.0%
Taylor expanded in x around 0 100.0%
neg-mul-1100.0%
+-commutative100.0%
unsub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 97.9%
mul-1-neg97.9%
Simplified97.9%
if -1.75 < x < 1Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 97.6%
sub-neg97.6%
neg-mul-197.6%
metadata-eval97.6%
+-commutative97.6%
unsub-neg97.6%
Simplified97.6%
Final simplification97.8%
(FPCore (x)
:precision binary64
(let* ((t_0 (/ x (+ x 1.0))))
(if (<= x -1.0)
(+ (/ 1.0 x) t_0)
(if (<= x 1.0) (+ t_0 (- -1.0 x)) (/ (- (/ -1.0 x) x) (- x))))))
double code(double x) {
double t_0 = x / (x + 1.0);
double tmp;
if (x <= -1.0) {
tmp = (1.0 / x) + t_0;
} else if (x <= 1.0) {
tmp = t_0 + (-1.0 - x);
} else {
tmp = ((-1.0 / x) - x) / -x;
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
real(8) :: tmp
t_0 = x / (x + 1.0d0)
if (x <= (-1.0d0)) then
tmp = (1.0d0 / x) + t_0
else if (x <= 1.0d0) then
tmp = t_0 + ((-1.0d0) - x)
else
tmp = (((-1.0d0) / x) - x) / -x
end if
code = tmp
end function
public static double code(double x) {
double t_0 = x / (x + 1.0);
double tmp;
if (x <= -1.0) {
tmp = (1.0 / x) + t_0;
} else if (x <= 1.0) {
tmp = t_0 + (-1.0 - x);
} else {
tmp = ((-1.0 / x) - x) / -x;
}
return tmp;
}
def code(x): t_0 = x / (x + 1.0) tmp = 0 if x <= -1.0: tmp = (1.0 / x) + t_0 elif x <= 1.0: tmp = t_0 + (-1.0 - x) else: tmp = ((-1.0 / x) - x) / -x return tmp
function code(x) t_0 = Float64(x / Float64(x + 1.0)) tmp = 0.0 if (x <= -1.0) tmp = Float64(Float64(1.0 / x) + t_0); elseif (x <= 1.0) tmp = Float64(t_0 + Float64(-1.0 - x)); else tmp = Float64(Float64(Float64(-1.0 / x) - x) / Float64(-x)); end return tmp end
function tmp_2 = code(x) t_0 = x / (x + 1.0); tmp = 0.0; if (x <= -1.0) tmp = (1.0 / x) + t_0; elseif (x <= 1.0) tmp = t_0 + (-1.0 - x); else tmp = ((-1.0 / x) - x) / -x; end tmp_2 = tmp; end
code[x_] := Block[{t$95$0 = N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, -1.0], N[(N[(1.0 / x), $MachinePrecision] + t$95$0), $MachinePrecision], If[LessEqual[x, 1.0], N[(t$95$0 + N[(-1.0 - x), $MachinePrecision]), $MachinePrecision], N[(N[(N[(-1.0 / x), $MachinePrecision] - x), $MachinePrecision] / (-x)), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{x}{x + 1}\\
\mathbf{if}\;x \leq -1:\\
\;\;\;\;\frac{1}{x} + t_0\\
\mathbf{elif}\;x \leq 1:\\
\;\;\;\;t_0 + \left(-1 - x\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{-1}{x} - x}{-x}\\
\end{array}
\end{array}
if x < -1Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around inf 98.6%
if -1 < x < 1Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 97.6%
sub-neg97.6%
neg-mul-197.6%
metadata-eval97.6%
+-commutative97.6%
unsub-neg97.6%
Simplified97.6%
if 1 < x Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add99.9%
*-un-lft-identity99.9%
+-commutative99.9%
+-commutative99.9%
Applied egg-rr99.9%
*-rgt-identity99.9%
associate-*l/54.4%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.7%
Applied egg-rr99.7%
Simplified100.0%
Taylor expanded in x around 0 100.0%
neg-mul-1100.0%
+-commutative100.0%
unsub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 97.2%
mul-1-neg97.2%
Simplified97.2%
Final simplification97.8%
(FPCore (x) :precision binary64 (if (or (<= x -1.0) (not (<= x 1.78))) (/ (- (/ -1.0 x) x) (- x)) (+ x (/ 1.0 (+ -1.0 x)))))
double code(double x) {
double tmp;
if ((x <= -1.0) || !(x <= 1.78)) {
tmp = ((-1.0 / x) - x) / -x;
} else {
tmp = x + (1.0 / (-1.0 + x));
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: tmp
if ((x <= (-1.0d0)) .or. (.not. (x <= 1.78d0))) then
tmp = (((-1.0d0) / x) - x) / -x
else
tmp = x + (1.0d0 / ((-1.0d0) + x))
end if
code = tmp
end function
public static double code(double x) {
double tmp;
if ((x <= -1.0) || !(x <= 1.78)) {
tmp = ((-1.0 / x) - x) / -x;
} else {
tmp = x + (1.0 / (-1.0 + x));
}
return tmp;
}
def code(x): tmp = 0 if (x <= -1.0) or not (x <= 1.78): tmp = ((-1.0 / x) - x) / -x else: tmp = x + (1.0 / (-1.0 + x)) return tmp
function code(x) tmp = 0.0 if ((x <= -1.0) || !(x <= 1.78)) tmp = Float64(Float64(Float64(-1.0 / x) - x) / Float64(-x)); else tmp = Float64(x + Float64(1.0 / Float64(-1.0 + x))); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if ((x <= -1.0) || ~((x <= 1.78))) tmp = ((-1.0 / x) - x) / -x; else tmp = x + (1.0 / (-1.0 + x)); end tmp_2 = tmp; end
code[x_] := If[Or[LessEqual[x, -1.0], N[Not[LessEqual[x, 1.78]], $MachinePrecision]], N[(N[(N[(-1.0 / x), $MachinePrecision] - x), $MachinePrecision] / (-x)), $MachinePrecision], N[(x + N[(1.0 / N[(-1.0 + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1.78\right):\\
\;\;\;\;\frac{\frac{-1}{x} - x}{-x}\\
\mathbf{else}:\\
\;\;\;\;x + \frac{1}{-1 + x}\\
\end{array}
\end{array}
if x < -1 or 1.78000000000000003 < x Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/53.3%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.7%
Applied egg-rr99.7%
Simplified100.0%
Taylor expanded in x around 0 100.0%
neg-mul-1100.0%
+-commutative100.0%
unsub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 97.9%
mul-1-neg97.9%
Simplified97.9%
if -1 < x < 1.78000000000000003Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 97.6%
Final simplification97.8%
(FPCore (x) :precision binary64 (if (<= x -1.0) 1.0 (if (<= x 1.92) (+ x (/ 1.0 (+ -1.0 x))) 1.0)))
double code(double x) {
double tmp;
if (x <= -1.0) {
tmp = 1.0;
} else if (x <= 1.92) {
tmp = x + (1.0 / (-1.0 + x));
} else {
tmp = 1.0;
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: tmp
if (x <= (-1.0d0)) then
tmp = 1.0d0
else if (x <= 1.92d0) then
tmp = x + (1.0d0 / ((-1.0d0) + x))
else
tmp = 1.0d0
end if
code = tmp
end function
public static double code(double x) {
double tmp;
if (x <= -1.0) {
tmp = 1.0;
} else if (x <= 1.92) {
tmp = x + (1.0 / (-1.0 + x));
} else {
tmp = 1.0;
}
return tmp;
}
def code(x): tmp = 0 if x <= -1.0: tmp = 1.0 elif x <= 1.92: tmp = x + (1.0 / (-1.0 + x)) else: tmp = 1.0 return tmp
function code(x) tmp = 0.0 if (x <= -1.0) tmp = 1.0; elseif (x <= 1.92) tmp = Float64(x + Float64(1.0 / Float64(-1.0 + x))); else tmp = 1.0; end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (x <= -1.0) tmp = 1.0; elseif (x <= 1.92) tmp = x + (1.0 / (-1.0 + x)); else tmp = 1.0; end tmp_2 = tmp; end
code[x_] := If[LessEqual[x, -1.0], 1.0, If[LessEqual[x, 1.92], N[(x + N[(1.0 / N[(-1.0 + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1:\\
\;\;\;\;1\\
\mathbf{elif}\;x \leq 1.92:\\
\;\;\;\;x + \frac{1}{-1 + x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -1 or 1.9199999999999999 < x Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/53.3%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.7%
Applied egg-rr99.7%
Simplified100.0%
Taylor expanded in x around inf 97.8%
if -1 < x < 1.9199999999999999Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 97.6%
Final simplification97.7%
(FPCore (x) :precision binary64 (if (<= x -1.0) 1.0 (if (<= x 1.0) -1.0 1.0)))
double code(double x) {
double tmp;
if (x <= -1.0) {
tmp = 1.0;
} else if (x <= 1.0) {
tmp = -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: tmp
if (x <= (-1.0d0)) then
tmp = 1.0d0
else if (x <= 1.0d0) then
tmp = -1.0d0
else
tmp = 1.0d0
end if
code = tmp
end function
public static double code(double x) {
double tmp;
if (x <= -1.0) {
tmp = 1.0;
} else if (x <= 1.0) {
tmp = -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(x): tmp = 0 if x <= -1.0: tmp = 1.0 elif x <= 1.0: tmp = -1.0 else: tmp = 1.0 return tmp
function code(x) tmp = 0.0 if (x <= -1.0) tmp = 1.0; elseif (x <= 1.0) tmp = -1.0; else tmp = 1.0; end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (x <= -1.0) tmp = 1.0; elseif (x <= 1.0) tmp = -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[x_] := If[LessEqual[x, -1.0], 1.0, If[LessEqual[x, 1.0], -1.0, 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1:\\
\;\;\;\;1\\
\mathbf{elif}\;x \leq 1:\\
\;\;\;\;-1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -1 or 1 < x Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/53.3%
associate-/l*100.0%
Simplified100.0%
frac-2neg100.0%
div-inv99.7%
Applied egg-rr99.7%
Simplified100.0%
Taylor expanded in x around inf 97.8%
if -1 < x < 1Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 97.6%
Final simplification97.7%
(FPCore (x) :precision binary64 (+ (/ x (+ x 1.0)) (/ 1.0 (+ -1.0 x))))
double code(double x) {
return (x / (x + 1.0)) + (1.0 / (-1.0 + x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (x / (x + 1.0d0)) + (1.0d0 / ((-1.0d0) + x))
end function
public static double code(double x) {
return (x / (x + 1.0)) + (1.0 / (-1.0 + x));
}
def code(x): return (x / (x + 1.0)) + (1.0 / (-1.0 + x))
function code(x) return Float64(Float64(x / Float64(x + 1.0)) + Float64(1.0 / Float64(-1.0 + x))) end
function tmp = code(x) tmp = (x / (x + 1.0)) + (1.0 / (-1.0 + x)); end
code[x_] := N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(-1.0 + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{x}{x + 1} + \frac{1}{-1 + x}
\end{array}
Initial program 100.0%
Final simplification100.0%
(FPCore (x) :precision binary64 -2.0)
double code(double x) {
return -2.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = -2.0d0
end function
public static double code(double x) {
return -2.0;
}
def code(x): return -2.0
function code(x) return -2.0 end
function tmp = code(x) tmp = -2.0; end
code[x_] := -2.0
\begin{array}{l}
\\
-2
\end{array}
Initial program 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
clear-num100.0%
frac-add100.0%
*-un-lft-identity100.0%
+-commutative100.0%
+-commutative100.0%
Applied egg-rr100.0%
*-rgt-identity100.0%
associate-*l/76.1%
associate-/l*100.0%
Simplified100.0%
associate-/r/99.8%
div-inv99.7%
associate-*r*99.7%
Applied egg-rr99.7%
Taylor expanded in x around inf 51.9%
sub-neg51.9%
+-commutative51.9%
metadata-eval51.9%
associate-+l+51.9%
associate-*r/51.9%
metadata-eval51.9%
Simplified51.9%
Applied egg-rr10.0%
Final simplification10.0%
(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 100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 48.4%
Final simplification48.4%
herbie shell --seed 2024026
(FPCore (x)
:name "Asymptote B"
:precision binary64
(+ (/ 1.0 (- x 1.0)) (/ x (+ x 1.0))))