Asymptote C

Percentage Accurate: 54.5% → 99.3%
Time: 7.1s
Alternatives: 10
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \frac{x}{x + 1} - \frac{x + 1}{x - 1} \end{array} \]
(FPCore (x) :precision binary64 (- (/ x (+ x 1.0)) (/ (+ x 1.0) (- x 1.0))))
double code(double x) {
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (x / (x + 1.0d0)) - ((x + 1.0d0) / (x - 1.0d0))
end function
public static double code(double x) {
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
}
def code(x):
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0))
function code(x)
	return Float64(Float64(x / Float64(x + 1.0)) - Float64(Float64(x + 1.0) / Float64(x - 1.0)))
end
function tmp = code(x)
	tmp = (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
end
code[x_] := N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(N[(x + 1.0), $MachinePrecision] / N[(x - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{x}{x + 1} - \frac{x + 1}{x - 1}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 10 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 54.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{x}{x + 1} - \frac{x + 1}{x - 1} \end{array} \]
(FPCore (x) :precision binary64 (- (/ x (+ x 1.0)) (/ (+ x 1.0) (- x 1.0))))
double code(double x) {
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (x / (x + 1.0d0)) - ((x + 1.0d0) / (x - 1.0d0))
end function
public static double code(double x) {
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
}
def code(x):
	return (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0))
function code(x)
	return Float64(Float64(x / Float64(x + 1.0)) - Float64(Float64(x + 1.0) / Float64(x - 1.0)))
end
function tmp = code(x)
	tmp = (x / (x + 1.0)) - ((x + 1.0) / (x - 1.0));
end
code[x_] := N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(N[(x + 1.0), $MachinePrecision] / N[(x - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{x}{x + 1} - \frac{x + 1}{x - 1}
\end{array}

Alternative 1: 99.3% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{x}{x + 1}\\ \mathbf{if}\;t\_0 + \frac{x + 1}{1 - x} \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;t\_0 + \left(\frac{x}{1 - x} + \frac{1}{1 - x}\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (/ x (+ x 1.0))))
   (if (<= (+ t_0 (/ (+ x 1.0) (- 1.0 x))) 5e-13)
     (/ (+ -1.0 (+ -2.0 (/ (+ -1.0 (/ -3.0 x)) x))) x)
     (+ t_0 (+ (/ x (- 1.0 x)) (/ 1.0 (- 1.0 x)))))))
double code(double x) {
	double t_0 = x / (x + 1.0);
	double tmp;
	if ((t_0 + ((x + 1.0) / (1.0 - x))) <= 5e-13) {
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	} else {
		tmp = t_0 + ((x / (1.0 - x)) + (1.0 / (1.0 - 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 ((t_0 + ((x + 1.0d0) / (1.0d0 - x))) <= 5d-13) then
        tmp = ((-1.0d0) + ((-2.0d0) + (((-1.0d0) + ((-3.0d0) / x)) / x))) / x
    else
        tmp = t_0 + ((x / (1.0d0 - x)) + (1.0d0 / (1.0d0 - x)))
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = x / (x + 1.0);
	double tmp;
	if ((t_0 + ((x + 1.0) / (1.0 - x))) <= 5e-13) {
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	} else {
		tmp = t_0 + ((x / (1.0 - x)) + (1.0 / (1.0 - x)));
	}
	return tmp;
}
def code(x):
	t_0 = x / (x + 1.0)
	tmp = 0
	if (t_0 + ((x + 1.0) / (1.0 - x))) <= 5e-13:
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x
	else:
		tmp = t_0 + ((x / (1.0 - x)) + (1.0 / (1.0 - x)))
	return tmp
function code(x)
	t_0 = Float64(x / Float64(x + 1.0))
	tmp = 0.0
	if (Float64(t_0 + Float64(Float64(x + 1.0) / Float64(1.0 - x))) <= 5e-13)
		tmp = Float64(Float64(-1.0 + Float64(-2.0 + Float64(Float64(-1.0 + Float64(-3.0 / x)) / x))) / x);
	else
		tmp = Float64(t_0 + Float64(Float64(x / Float64(1.0 - x)) + Float64(1.0 / Float64(1.0 - x))));
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = x / (x + 1.0);
	tmp = 0.0;
	if ((t_0 + ((x + 1.0) / (1.0 - x))) <= 5e-13)
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	else
		tmp = t_0 + ((x / (1.0 - x)) + (1.0 / (1.0 - x)));
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(t$95$0 + N[(N[(x + 1.0), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 5e-13], N[(N[(-1.0 + N[(-2.0 + N[(N[(-1.0 + N[(-3.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], N[(t$95$0 + N[(N[(x / N[(1.0 - x), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{x}{x + 1}\\
\mathbf{if}\;t\_0 + \frac{x + 1}{1 - x} \leq 5 \cdot 10^{-13}:\\
\;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\

\mathbf{else}:\\
\;\;\;\;t\_0 + \left(\frac{x}{1 - x} + \frac{1}{1 - x}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64)))) < 4.9999999999999999e-13

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.4%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg99.4%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval99.4%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative99.4%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg99.4%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg99.4%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/99.4%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval99.4%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]
    8. Step-by-step derivation
      1. expm1-log1p-u0.0%

        \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 - \frac{1 + \frac{3}{x}}{x}\right)\right)}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(\color{blue}{-3 + \left(-\frac{1 + \frac{3}{x}}{x}\right)}\right)\right)}{x} \]
      3. distribute-neg-frac0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \color{blue}{\frac{-\left(1 + \frac{3}{x}\right)}{x}}\right)\right)}{x} \]
      4. +-commutative0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{-\color{blue}{\left(\frac{3}{x} + 1\right)}}{x}\right)\right)}{x} \]
      5. distribute-neg-in0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\left(-\frac{3}{x}\right) + \left(-1\right)}}{x}\right)\right)}{x} \]
      6. distribute-frac-neg20.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{3}{-x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      7. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{\color{blue}{--3}}{-x} + \left(-1\right)}{x}\right)\right)}{x} \]
      8. frac-2neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{-3}{x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      9. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + \color{blue}{-1}}{x}\right)\right)}{x} \]
    9. Applied egg-rr0.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}}{x} \]
    10. Step-by-step derivation
      1. expm1-undefine0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} - 1}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}}{x} \]
      3. log1p-undefine0.0%

        \[\leadsto \frac{e^{\color{blue}{\log \left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}} + \left(-1\right)}{x} \]
      4. rem-exp-log99.4%

        \[\leadsto \frac{\color{blue}{\left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)} + \left(-1\right)}{x} \]
      5. associate-+r+99.5%

        \[\leadsto \frac{\color{blue}{\left(\left(1 + -3\right) + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}{x} \]
      6. metadata-eval99.5%

        \[\leadsto \frac{\left(\color{blue}{-2} + \frac{\frac{-3}{x} + -1}{x}\right) + \left(-1\right)}{x} \]
      7. +-commutative99.5%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1 + \frac{-3}{x}}}{x}\right) + \left(-1\right)}{x} \]
      8. metadata-eval99.5%

        \[\leadsto \frac{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + \color{blue}{-1}}{x} \]
    11. Simplified99.5%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + -1}}{x} \]

    if 4.9999999999999999e-13 < (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64))))

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. div-sub100.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(\frac{-1}{1 - x} - \frac{x}{1 - x}\right)} \]
      2. sub-neg100.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(\frac{-1}{1 - x} + \left(-\frac{x}{1 - x}\right)\right)} \]
      3. frac-2neg100.0%

        \[\leadsto \frac{x}{x + 1} - \left(\color{blue}{\frac{--1}{-\left(1 - x\right)}} + \left(-\frac{x}{1 - x}\right)\right) \]
      4. metadata-eval100.0%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{\color{blue}{1}}{-\left(1 - x\right)} + \left(-\frac{x}{1 - x}\right)\right) \]
      5. flip--99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{-\color{blue}{\frac{1 \cdot 1 - x \cdot x}{1 + x}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      6. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{-\frac{\color{blue}{1} - x \cdot x}{1 + x}} + \left(-\frac{x}{1 - x}\right)\right) \]
      7. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{-\frac{\color{blue}{-1 \cdot -1} - x \cdot x}{1 + x}} + \left(-\frac{x}{1 - x}\right)\right) \]
      8. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{-\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{x + 1}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      9. distribute-neg-frac299.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\color{blue}{\frac{-1 \cdot -1 - x \cdot x}{-\left(x + 1\right)}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      10. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{-\color{blue}{\left(1 + x\right)}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      11. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{\left(-1\right) + \left(-x\right)}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      12. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1} + \left(-x\right)}} + \left(-\frac{x}{1 - x}\right)\right) \]
      13. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 - x}}} + \left(-\frac{x}{1 - x}\right)\right) \]
      14. flip-+100.0%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\color{blue}{-1 + x}} + \left(-\frac{x}{1 - x}\right)\right) \]
      15. +-commutative100.0%

        \[\leadsto \frac{x}{x + 1} - \left(\frac{1}{\color{blue}{x + -1}} + \left(-\frac{x}{1 - x}\right)\right) \]
    6. Applied egg-rr100.0%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(\frac{1}{x + -1} + \left(-\frac{x}{1 - x}\right)\right)} \]
    7. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(\frac{1}{x + -1} - \frac{x}{1 - x}\right)} \]
    8. Simplified100.0%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(\frac{1}{x + -1} - \frac{x}{1 - x}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{x + 1} + \left(\frac{x}{1 - x} + \frac{1}{1 - x}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.4% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \mathbf{if}\;t\_0 \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (+ (/ x (+ x 1.0)) (/ (+ x 1.0) (- 1.0 x)))))
   (if (<= t_0 5e-13) (/ (+ -1.0 (+ -2.0 (/ (+ -1.0 (/ -3.0 x)) x))) x) t_0)))
double code(double x) {
	double t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	double tmp;
	if (t_0 <= 5e-13) {
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	} else {
		tmp = t_0;
	}
	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)) + ((x + 1.0d0) / (1.0d0 - x))
    if (t_0 <= 5d-13) then
        tmp = ((-1.0d0) + ((-2.0d0) + (((-1.0d0) + ((-3.0d0) / x)) / x))) / x
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	double tmp;
	if (t_0 <= 5e-13) {
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x):
	t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))
	tmp = 0
	if t_0 <= 5e-13:
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x
	else:
		tmp = t_0
	return tmp
function code(x)
	t_0 = Float64(Float64(x / Float64(x + 1.0)) + Float64(Float64(x + 1.0) / Float64(1.0 - x)))
	tmp = 0.0
	if (t_0 <= 5e-13)
		tmp = Float64(Float64(-1.0 + Float64(-2.0 + Float64(Float64(-1.0 + Float64(-3.0 / x)) / x))) / x);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	tmp = 0.0;
	if (t_0 <= 5e-13)
		tmp = (-1.0 + (-2.0 + ((-1.0 + (-3.0 / x)) / x))) / x;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(x + 1.0), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, 5e-13], N[(N[(-1.0 + N[(-2.0 + N[(N[(-1.0 + N[(-3.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], t$95$0]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{x}{x + 1} + \frac{x + 1}{1 - x}\\
\mathbf{if}\;t\_0 \leq 5 \cdot 10^{-13}:\\
\;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64)))) < 4.9999999999999999e-13

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.4%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg99.4%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval99.4%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative99.4%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg99.4%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg99.4%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/99.4%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval99.4%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]
    8. Step-by-step derivation
      1. expm1-log1p-u0.0%

        \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 - \frac{1 + \frac{3}{x}}{x}\right)\right)}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(\color{blue}{-3 + \left(-\frac{1 + \frac{3}{x}}{x}\right)}\right)\right)}{x} \]
      3. distribute-neg-frac0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \color{blue}{\frac{-\left(1 + \frac{3}{x}\right)}{x}}\right)\right)}{x} \]
      4. +-commutative0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{-\color{blue}{\left(\frac{3}{x} + 1\right)}}{x}\right)\right)}{x} \]
      5. distribute-neg-in0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\left(-\frac{3}{x}\right) + \left(-1\right)}}{x}\right)\right)}{x} \]
      6. distribute-frac-neg20.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{3}{-x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      7. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{\color{blue}{--3}}{-x} + \left(-1\right)}{x}\right)\right)}{x} \]
      8. frac-2neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{-3}{x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      9. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + \color{blue}{-1}}{x}\right)\right)}{x} \]
    9. Applied egg-rr0.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}}{x} \]
    10. Step-by-step derivation
      1. expm1-undefine0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} - 1}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}}{x} \]
      3. log1p-undefine0.0%

        \[\leadsto \frac{e^{\color{blue}{\log \left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}} + \left(-1\right)}{x} \]
      4. rem-exp-log99.4%

        \[\leadsto \frac{\color{blue}{\left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)} + \left(-1\right)}{x} \]
      5. associate-+r+99.5%

        \[\leadsto \frac{\color{blue}{\left(\left(1 + -3\right) + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}{x} \]
      6. metadata-eval99.5%

        \[\leadsto \frac{\left(\color{blue}{-2} + \frac{\frac{-3}{x} + -1}{x}\right) + \left(-1\right)}{x} \]
      7. +-commutative99.5%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1 + \frac{-3}{x}}}{x}\right) + \left(-1\right)}{x} \]
      8. metadata-eval99.5%

        \[\leadsto \frac{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + \color{blue}{-1}}{x} \]
    11. Simplified99.5%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + -1}}{x} \]

    if 4.9999999999999999e-13 < (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64))))

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.4% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \mathbf{if}\;t\_0 \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (+ (/ x (+ x 1.0)) (/ (+ x 1.0) (- 1.0 x)))))
   (if (<= t_0 5e-13) (/ (+ -3.0 (/ (- -1.0 (/ 3.0 x)) x)) x) t_0)))
double code(double x) {
	double t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	double tmp;
	if (t_0 <= 5e-13) {
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	} else {
		tmp = t_0;
	}
	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)) + ((x + 1.0d0) / (1.0d0 - x))
    if (t_0 <= 5d-13) then
        tmp = ((-3.0d0) + (((-1.0d0) - (3.0d0 / x)) / x)) / x
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	double tmp;
	if (t_0 <= 5e-13) {
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x):
	t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))
	tmp = 0
	if t_0 <= 5e-13:
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x
	else:
		tmp = t_0
	return tmp
function code(x)
	t_0 = Float64(Float64(x / Float64(x + 1.0)) + Float64(Float64(x + 1.0) / Float64(1.0 - x)))
	tmp = 0.0
	if (t_0 <= 5e-13)
		tmp = Float64(Float64(-3.0 + Float64(Float64(-1.0 - Float64(3.0 / x)) / x)) / x);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = (x / (x + 1.0)) + ((x + 1.0) / (1.0 - x));
	tmp = 0.0;
	if (t_0 <= 5e-13)
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(x + 1.0), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, 5e-13], N[(N[(-3.0 + N[(N[(-1.0 - N[(3.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], t$95$0]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{x}{x + 1} + \frac{x + 1}{1 - x}\\
\mathbf{if}\;t\_0 \leq 5 \cdot 10^{-13}:\\
\;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64)))) < 4.9999999999999999e-13

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.4%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg99.4%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval99.4%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative99.4%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg99.4%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg99.4%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/99.4%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval99.4%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]

    if 4.9999999999999999e-13 < (-.f64 (/.f64 x (+.f64 x #s(literal 1 binary64))) (/.f64 (+.f64 x #s(literal 1 binary64)) (-.f64 x #s(literal 1 binary64))))

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 5 \cdot 10^{-13}:\\ \;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.1% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.0)
   (/ (+ -1.0 (+ -2.0 (/ -1.0 x))) x)
   (if (<= x 1.0)
     (+ 1.0 (* x (+ x 3.0)))
     (/ (+ -3.0 (/ (- -1.0 (/ 3.0 x)) x)) x))))
double code(double x) {
	double tmp;
	if (x <= -1.0) {
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	} else if (x <= 1.0) {
		tmp = 1.0 + (x * (x + 3.0));
	} else {
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.0d0)) then
        tmp = ((-1.0d0) + ((-2.0d0) + ((-1.0d0) / x))) / x
    else if (x <= 1.0d0) then
        tmp = 1.0d0 + (x * (x + 3.0d0))
    else
        tmp = ((-3.0d0) + (((-1.0d0) - (3.0d0 / x)) / x)) / x
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.0) {
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	} else if (x <= 1.0) {
		tmp = 1.0 + (x * (x + 3.0));
	} else {
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.0:
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x
	elif x <= 1.0:
		tmp = 1.0 + (x * (x + 3.0))
	else:
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.0)
		tmp = Float64(Float64(-1.0 + Float64(-2.0 + Float64(-1.0 / x))) / x);
	elseif (x <= 1.0)
		tmp = Float64(1.0 + Float64(x * Float64(x + 3.0)));
	else
		tmp = Float64(Float64(-3.0 + Float64(Float64(-1.0 - Float64(3.0 / x)) / x)) / x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.0)
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	elseif (x <= 1.0)
		tmp = 1.0 + (x * (x + 3.0));
	else
		tmp = (-3.0 + ((-1.0 - (3.0 / x)) / x)) / x;
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.0], N[(N[(-1.0 + N[(-2.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], If[LessEqual[x, 1.0], N[(1.0 + N[(x * N[(x + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-3.0 + N[(N[(-1.0 - N[(3.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1:\\
\;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\

\mathbf{elif}\;x \leq 1:\\
\;\;\;\;1 + x \cdot \left(x + 3\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1

    1. Initial program 6.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg26.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub06.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub06.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified6.0%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 100.0%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval100.0%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative100.0%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg100.0%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg100.0%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/100.0%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval100.0%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]
    8. Step-by-step derivation
      1. expm1-log1p-u0.0%

        \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 - \frac{1 + \frac{3}{x}}{x}\right)\right)}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(\color{blue}{-3 + \left(-\frac{1 + \frac{3}{x}}{x}\right)}\right)\right)}{x} \]
      3. distribute-neg-frac0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \color{blue}{\frac{-\left(1 + \frac{3}{x}\right)}{x}}\right)\right)}{x} \]
      4. +-commutative0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{-\color{blue}{\left(\frac{3}{x} + 1\right)}}{x}\right)\right)}{x} \]
      5. distribute-neg-in0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\left(-\frac{3}{x}\right) + \left(-1\right)}}{x}\right)\right)}{x} \]
      6. distribute-frac-neg20.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{3}{-x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      7. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{\color{blue}{--3}}{-x} + \left(-1\right)}{x}\right)\right)}{x} \]
      8. frac-2neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{-3}{x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      9. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + \color{blue}{-1}}{x}\right)\right)}{x} \]
    9. Applied egg-rr0.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}}{x} \]
    10. Step-by-step derivation
      1. expm1-undefine0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} - 1}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}}{x} \]
      3. log1p-undefine0.0%

        \[\leadsto \frac{e^{\color{blue}{\log \left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}} + \left(-1\right)}{x} \]
      4. rem-exp-log100.0%

        \[\leadsto \frac{\color{blue}{\left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)} + \left(-1\right)}{x} \]
      5. associate-+r+100.0%

        \[\leadsto \frac{\color{blue}{\left(\left(1 + -3\right) + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}{x} \]
      6. metadata-eval100.0%

        \[\leadsto \frac{\left(\color{blue}{-2} + \frac{\frac{-3}{x} + -1}{x}\right) + \left(-1\right)}{x} \]
      7. +-commutative100.0%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1 + \frac{-3}{x}}}{x}\right) + \left(-1\right)}{x} \]
      8. metadata-eval100.0%

        \[\leadsto \frac{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + \color{blue}{-1}}{x} \]
    11. Simplified100.0%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + -1}}{x} \]
    12. Taylor expanded in x around inf 100.0%

      \[\leadsto \frac{\color{blue}{-1 \cdot \left(2 + \frac{1}{x}\right)} + -1}{x} \]
    13. Step-by-step derivation
      1. mul-1-neg100.0%

        \[\leadsto \frac{\color{blue}{\left(-\left(2 + \frac{1}{x}\right)\right)} + -1}{x} \]
      2. distribute-neg-in100.0%

        \[\leadsto \frac{\color{blue}{\left(\left(-2\right) + \left(-\frac{1}{x}\right)\right)} + -1}{x} \]
      3. metadata-eval100.0%

        \[\leadsto \frac{\left(\color{blue}{-2} + \left(-\frac{1}{x}\right)\right) + -1}{x} \]
      4. distribute-neg-frac100.0%

        \[\leadsto \frac{\left(-2 + \color{blue}{\frac{-1}{x}}\right) + -1}{x} \]
      5. metadata-eval100.0%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1}}{x}\right) + -1}{x} \]
    14. Simplified100.0%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1}{x}\right)} + -1}{x} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.4%

      \[\leadsto \color{blue}{1 + x \cdot \left(3 + x\right)} \]

    if 1 < x

    1. Initial program 8.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg28.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub08.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub08.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified8.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.0%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg99.0%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval99.0%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative99.0%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg99.0%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg99.0%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/99.0%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval99.0%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified99.0%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 + \frac{-1 - \frac{3}{x}}{x}}{x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 98.9% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 1.0)))
   (/ (+ -3.0 (/ -1.0 x)) x)
   (+ 1.0 (* x (+ x 3.0)))))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = (-3.0 + (-1.0 / x)) / x;
	} else {
		tmp = 1.0 + (x * (x + 3.0));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if ((x <= (-1.0d0)) .or. (.not. (x <= 1.0d0))) then
        tmp = ((-3.0d0) + ((-1.0d0) / x)) / x
    else
        tmp = 1.0d0 + (x * (x + 3.0d0))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = (-3.0 + (-1.0 / x)) / x;
	} else {
		tmp = 1.0 + (x * (x + 3.0));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 1.0):
		tmp = (-3.0 + (-1.0 / x)) / x
	else:
		tmp = 1.0 + (x * (x + 3.0))
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 1.0))
		tmp = Float64(Float64(-3.0 + Float64(-1.0 / x)) / x);
	else
		tmp = Float64(1.0 + Float64(x * Float64(x + 3.0)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x <= -1.0) || ~((x <= 1.0)))
		tmp = (-3.0 + (-1.0 / x)) / x;
	else
		tmp = 1.0 + (x * (x + 3.0));
	end
	tmp_2 = tmp;
end
code[x_] := If[Or[LessEqual[x, -1.0], N[Not[LessEqual[x, 1.0]], $MachinePrecision]], N[(N[(-3.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], N[(1.0 + N[(x * N[(x + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\
\;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\

\mathbf{else}:\\
\;\;\;\;1 + x \cdot \left(x + 3\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1 or 1 < x

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.1%

      \[\leadsto \color{blue}{-1 \cdot \frac{3 + \frac{1}{x}}{x}} \]
    6. Step-by-step derivation
      1. associate-*r/99.1%

        \[\leadsto \color{blue}{\frac{-1 \cdot \left(3 + \frac{1}{x}\right)}{x}} \]
      2. neg-mul-199.1%

        \[\leadsto \frac{\color{blue}{-\left(3 + \frac{1}{x}\right)}}{x} \]
      3. distribute-neg-in99.1%

        \[\leadsto \frac{\color{blue}{\left(-3\right) + \left(-\frac{1}{x}\right)}}{x} \]
      4. metadata-eval99.1%

        \[\leadsto \frac{\color{blue}{-3} + \left(-\frac{1}{x}\right)}{x} \]
      5. distribute-neg-frac99.1%

        \[\leadsto \frac{-3 + \color{blue}{\frac{-1}{x}}}{x} \]
      6. metadata-eval99.1%

        \[\leadsto \frac{-3 + \frac{\color{blue}{-1}}{x}}{x} \]
    7. Simplified99.1%

      \[\leadsto \color{blue}{\frac{-3 + \frac{-1}{x}}{x}} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.4%

      \[\leadsto \color{blue}{1 + x \cdot \left(3 + x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 98.4% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 1.0))) (/ -3.0 x) (+ 1.0 (* x (+ x 3.0)))))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0 + (x * (x + 3.0));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if ((x <= (-1.0d0)) .or. (.not. (x <= 1.0d0))) then
        tmp = (-3.0d0) / x
    else
        tmp = 1.0d0 + (x * (x + 3.0d0))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0 + (x * (x + 3.0));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 1.0):
		tmp = -3.0 / x
	else:
		tmp = 1.0 + (x * (x + 3.0))
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 1.0))
		tmp = Float64(-3.0 / x);
	else
		tmp = Float64(1.0 + Float64(x * Float64(x + 3.0)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x <= -1.0) || ~((x <= 1.0)))
		tmp = -3.0 / x;
	else
		tmp = 1.0 + (x * (x + 3.0));
	end
	tmp_2 = tmp;
end
code[x_] := If[Or[LessEqual[x, -1.0], N[Not[LessEqual[x, 1.0]], $MachinePrecision]], N[(-3.0 / x), $MachinePrecision], N[(1.0 + N[(x * N[(x + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\
\;\;\;\;\frac{-3}{x}\\

\mathbf{else}:\\
\;\;\;\;1 + x \cdot \left(x + 3\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1 or 1 < x

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 98.6%

      \[\leadsto \color{blue}{\frac{-3}{x}} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.4%

      \[\leadsto \color{blue}{1 + x \cdot \left(3 + x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 98.9% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.0)
   (/ (+ -1.0 (+ -2.0 (/ -1.0 x))) x)
   (if (<= x 1.0) (+ 1.0 (* x (+ x 3.0))) (/ (+ -3.0 (/ -1.0 x)) x))))
double code(double x) {
	double tmp;
	if (x <= -1.0) {
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	} else if (x <= 1.0) {
		tmp = 1.0 + (x * (x + 3.0));
	} else {
		tmp = (-3.0 + (-1.0 / x)) / x;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.0d0)) then
        tmp = ((-1.0d0) + ((-2.0d0) + ((-1.0d0) / x))) / x
    else if (x <= 1.0d0) then
        tmp = 1.0d0 + (x * (x + 3.0d0))
    else
        tmp = ((-3.0d0) + ((-1.0d0) / x)) / x
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.0) {
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	} else if (x <= 1.0) {
		tmp = 1.0 + (x * (x + 3.0));
	} else {
		tmp = (-3.0 + (-1.0 / x)) / x;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.0:
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x
	elif x <= 1.0:
		tmp = 1.0 + (x * (x + 3.0))
	else:
		tmp = (-3.0 + (-1.0 / x)) / x
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.0)
		tmp = Float64(Float64(-1.0 + Float64(-2.0 + Float64(-1.0 / x))) / x);
	elseif (x <= 1.0)
		tmp = Float64(1.0 + Float64(x * Float64(x + 3.0)));
	else
		tmp = Float64(Float64(-3.0 + Float64(-1.0 / x)) / x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.0)
		tmp = (-1.0 + (-2.0 + (-1.0 / x))) / x;
	elseif (x <= 1.0)
		tmp = 1.0 + (x * (x + 3.0));
	else
		tmp = (-3.0 + (-1.0 / x)) / x;
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.0], N[(N[(-1.0 + N[(-2.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], If[LessEqual[x, 1.0], N[(1.0 + N[(x * N[(x + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-3.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1:\\
\;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\

\mathbf{elif}\;x \leq 1:\\
\;\;\;\;1 + x \cdot \left(x + 3\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1

    1. Initial program 6.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg26.0%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub06.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub06.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg6.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified6.0%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 100.0%

      \[\leadsto \color{blue}{\frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} - 3}{x}} \]
    6. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto \frac{\color{blue}{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \left(-3\right)}}{x} \]
      2. metadata-eval100.0%

        \[\leadsto \frac{-1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x} + \color{blue}{-3}}{x} \]
      3. +-commutative100.0%

        \[\leadsto \frac{\color{blue}{-3 + -1 \cdot \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      4. mul-1-neg100.0%

        \[\leadsto \frac{-3 + \color{blue}{\left(-\frac{1 + 3 \cdot \frac{1}{x}}{x}\right)}}{x} \]
      5. unsub-neg100.0%

        \[\leadsto \frac{\color{blue}{-3 - \frac{1 + 3 \cdot \frac{1}{x}}{x}}}{x} \]
      6. associate-*r/100.0%

        \[\leadsto \frac{-3 - \frac{1 + \color{blue}{\frac{3 \cdot 1}{x}}}{x}}{x} \]
      7. metadata-eval100.0%

        \[\leadsto \frac{-3 - \frac{1 + \frac{\color{blue}{3}}{x}}{x}}{x} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{\frac{-3 - \frac{1 + \frac{3}{x}}{x}}{x}} \]
    8. Step-by-step derivation
      1. expm1-log1p-u0.0%

        \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 - \frac{1 + \frac{3}{x}}{x}\right)\right)}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(\color{blue}{-3 + \left(-\frac{1 + \frac{3}{x}}{x}\right)}\right)\right)}{x} \]
      3. distribute-neg-frac0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \color{blue}{\frac{-\left(1 + \frac{3}{x}\right)}{x}}\right)\right)}{x} \]
      4. +-commutative0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{-\color{blue}{\left(\frac{3}{x} + 1\right)}}{x}\right)\right)}{x} \]
      5. distribute-neg-in0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\left(-\frac{3}{x}\right) + \left(-1\right)}}{x}\right)\right)}{x} \]
      6. distribute-frac-neg20.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{3}{-x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      7. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{\color{blue}{--3}}{-x} + \left(-1\right)}{x}\right)\right)}{x} \]
      8. frac-2neg0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\color{blue}{\frac{-3}{x}} + \left(-1\right)}{x}\right)\right)}{x} \]
      9. metadata-eval0.0%

        \[\leadsto \frac{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + \color{blue}{-1}}{x}\right)\right)}{x} \]
    9. Applied egg-rr0.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}}{x} \]
    10. Step-by-step derivation
      1. expm1-undefine0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} - 1}}{x} \]
      2. sub-neg0.0%

        \[\leadsto \frac{\color{blue}{e^{\mathsf{log1p}\left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}}{x} \]
      3. log1p-undefine0.0%

        \[\leadsto \frac{e^{\color{blue}{\log \left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)}} + \left(-1\right)}{x} \]
      4. rem-exp-log100.0%

        \[\leadsto \frac{\color{blue}{\left(1 + \left(-3 + \frac{\frac{-3}{x} + -1}{x}\right)\right)} + \left(-1\right)}{x} \]
      5. associate-+r+100.0%

        \[\leadsto \frac{\color{blue}{\left(\left(1 + -3\right) + \frac{\frac{-3}{x} + -1}{x}\right)} + \left(-1\right)}{x} \]
      6. metadata-eval100.0%

        \[\leadsto \frac{\left(\color{blue}{-2} + \frac{\frac{-3}{x} + -1}{x}\right) + \left(-1\right)}{x} \]
      7. +-commutative100.0%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1 + \frac{-3}{x}}}{x}\right) + \left(-1\right)}{x} \]
      8. metadata-eval100.0%

        \[\leadsto \frac{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + \color{blue}{-1}}{x} \]
    11. Simplified100.0%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1 + \frac{-3}{x}}{x}\right) + -1}}{x} \]
    12. Taylor expanded in x around inf 100.0%

      \[\leadsto \frac{\color{blue}{-1 \cdot \left(2 + \frac{1}{x}\right)} + -1}{x} \]
    13. Step-by-step derivation
      1. mul-1-neg100.0%

        \[\leadsto \frac{\color{blue}{\left(-\left(2 + \frac{1}{x}\right)\right)} + -1}{x} \]
      2. distribute-neg-in100.0%

        \[\leadsto \frac{\color{blue}{\left(\left(-2\right) + \left(-\frac{1}{x}\right)\right)} + -1}{x} \]
      3. metadata-eval100.0%

        \[\leadsto \frac{\left(\color{blue}{-2} + \left(-\frac{1}{x}\right)\right) + -1}{x} \]
      4. distribute-neg-frac100.0%

        \[\leadsto \frac{\left(-2 + \color{blue}{\frac{-1}{x}}\right) + -1}{x} \]
      5. metadata-eval100.0%

        \[\leadsto \frac{\left(-2 + \frac{\color{blue}{-1}}{x}\right) + -1}{x} \]
    14. Simplified100.0%

      \[\leadsto \frac{\color{blue}{\left(-2 + \frac{-1}{x}\right)} + -1}{x} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.4%

      \[\leadsto \color{blue}{1 + x \cdot \left(3 + x\right)} \]

    if 1 < x

    1. Initial program 8.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg28.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub08.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub08.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg8.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified8.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 98.3%

      \[\leadsto \color{blue}{-1 \cdot \frac{3 + \frac{1}{x}}{x}} \]
    6. Step-by-step derivation
      1. associate-*r/98.3%

        \[\leadsto \color{blue}{\frac{-1 \cdot \left(3 + \frac{1}{x}\right)}{x}} \]
      2. neg-mul-198.3%

        \[\leadsto \frac{\color{blue}{-\left(3 + \frac{1}{x}\right)}}{x} \]
      3. distribute-neg-in98.3%

        \[\leadsto \frac{\color{blue}{\left(-3\right) + \left(-\frac{1}{x}\right)}}{x} \]
      4. metadata-eval98.3%

        \[\leadsto \frac{\color{blue}{-3} + \left(-\frac{1}{x}\right)}{x} \]
      5. distribute-neg-frac98.3%

        \[\leadsto \frac{-3 + \color{blue}{\frac{-1}{x}}}{x} \]
      6. metadata-eval98.3%

        \[\leadsto \frac{-3 + \frac{\color{blue}{-1}}{x}}{x} \]
    7. Simplified98.3%

      \[\leadsto \color{blue}{\frac{-3 + \frac{-1}{x}}{x}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1:\\ \;\;\;\;\frac{-1 + \left(-2 + \frac{-1}{x}\right)}{x}\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 + \frac{-1}{x}}{x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 98.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot 3\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 1.0))) (/ -3.0 x) (+ 1.0 (* x 3.0))))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0 + (x * 3.0);
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if ((x <= (-1.0d0)) .or. (.not. (x <= 1.0d0))) then
        tmp = (-3.0d0) / x
    else
        tmp = 1.0d0 + (x * 3.0d0)
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0 + (x * 3.0);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 1.0):
		tmp = -3.0 / x
	else:
		tmp = 1.0 + (x * 3.0)
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 1.0))
		tmp = Float64(-3.0 / x);
	else
		tmp = Float64(1.0 + Float64(x * 3.0));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x <= -1.0) || ~((x <= 1.0)))
		tmp = -3.0 / x;
	else
		tmp = 1.0 + (x * 3.0);
	end
	tmp_2 = tmp;
end
code[x_] := If[Or[LessEqual[x, -1.0], N[Not[LessEqual[x, 1.0]], $MachinePrecision]], N[(-3.0 / x), $MachinePrecision], N[(1.0 + N[(x * 3.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\
\;\;\;\;\frac{-3}{x}\\

\mathbf{else}:\\
\;\;\;\;1 + x \cdot 3\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1 or 1 < x

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 98.6%

      \[\leadsto \color{blue}{\frac{-3}{x}} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 98.7%

      \[\leadsto \color{blue}{1 + 3 \cdot x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot 3\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 97.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 1.0))) (/ -3.0 x) 1.0))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if ((x <= (-1.0d0)) .or. (.not. (x <= 1.0d0))) then
        tmp = (-3.0d0) / x
    else
        tmp = 1.0d0
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = 1.0;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 1.0):
		tmp = -3.0 / x
	else:
		tmp = 1.0
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 1.0))
		tmp = Float64(-3.0 / x);
	else
		tmp = 1.0;
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x <= -1.0) || ~((x <= 1.0)))
		tmp = -3.0 / x;
	else
		tmp = 1.0;
	end
	tmp_2 = tmp;
end
code[x_] := If[Or[LessEqual[x, -1.0], N[Not[LessEqual[x, 1.0]], $MachinePrecision]], N[(-3.0 / x), $MachinePrecision], 1.0]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\
\;\;\;\;\frac{-3}{x}\\

\mathbf{else}:\\
\;\;\;\;1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1 or 1 < x

    1. Initial program 7.6%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg27.6%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub07.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg7.6%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 98.6%

      \[\leadsto \color{blue}{\frac{-3}{x}} \]

    if -1 < x < 1

    1. Initial program 99.9%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg299.9%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub099.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg99.9%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 97.2%

      \[\leadsto \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \]
  5. Add Preprocessing

Alternative 10: 50.7% accurate, 13.0× speedup?

\[\begin{array}{l} \\ 1 \end{array} \]
(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}
Derivation
  1. Initial program 50.5%

    \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
  2. Step-by-step derivation
    1. remove-double-neg50.5%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
    2. distribute-neg-frac50.5%

      \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
    3. distribute-neg-in50.5%

      \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
    4. sub-neg50.5%

      \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
    5. distribute-frac-neg250.5%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
    6. sub-neg50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
    7. +-commutative50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
    8. unsub-neg50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
    9. metadata-eval50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
    10. neg-sub050.5%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
    11. associate-+l-50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
    12. neg-sub050.5%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
    13. +-commutative50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
    14. unsub-neg50.5%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
  3. Simplified50.5%

    \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 47.0%

    \[\leadsto \color{blue}{1} \]
  6. Add Preprocessing

Reproduce

?
herbie shell --seed 2024135 
(FPCore (x)
  :name "Asymptote C"
  :precision binary64
  (- (/ x (+ x 1.0)) (/ (+ x 1.0) (- x 1.0))))