Asymptote C

Percentage Accurate: 54.8% → 99.5%
Time: 9.0s
Alternatives: 8
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 8 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: 54.8% 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: 99.5% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{\left(3 + \frac{2}{{x}^{2}}\right) - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{x + -1}{x + 1} - \frac{x + 1}{x}}{1 + \frac{-1}{x}}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (+ (/ x (+ x 1.0)) (/ (+ x 1.0) (- 1.0 x))) 4e-12)
   (/ (- (+ 3.0 (/ 2.0 (pow x 2.0))) (/ 2.0 x)) (- 1.0 x))
   (/ (- (/ (+ x -1.0) (+ x 1.0)) (/ (+ x 1.0) x)) (+ 1.0 (/ -1.0 x)))))
double code(double x) {
	double tmp;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12) {
		tmp = ((3.0 + (2.0 / pow(x, 2.0))) - (2.0 / x)) / (1.0 - x);
	} else {
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((x / (x + 1.0d0)) + ((x + 1.0d0) / (1.0d0 - x))) <= 4d-12) then
        tmp = ((3.0d0 + (2.0d0 / (x ** 2.0d0))) - (2.0d0 / x)) / (1.0d0 - x)
    else
        tmp = (((x + (-1.0d0)) / (x + 1.0d0)) - ((x + 1.0d0) / x)) / (1.0d0 + ((-1.0d0) / x))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12) {
		tmp = ((3.0 + (2.0 / Math.pow(x, 2.0))) - (2.0 / x)) / (1.0 - x);
	} else {
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if ((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12:
		tmp = ((3.0 + (2.0 / math.pow(x, 2.0))) - (2.0 / x)) / (1.0 - x)
	else:
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x))
	return tmp
function code(x)
	tmp = 0.0
	if (Float64(Float64(x / Float64(x + 1.0)) + Float64(Float64(x + 1.0) / Float64(1.0 - x))) <= 4e-12)
		tmp = Float64(Float64(Float64(3.0 + Float64(2.0 / (x ^ 2.0))) - Float64(2.0 / x)) / Float64(1.0 - x));
	else
		tmp = Float64(Float64(Float64(Float64(x + -1.0) / Float64(x + 1.0)) - Float64(Float64(x + 1.0) / x)) / Float64(1.0 + Float64(-1.0 / x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12)
		tmp = ((3.0 + (2.0 / (x ^ 2.0))) - (2.0 / x)) / (1.0 - x);
	else
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(x + 1.0), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 4e-12], N[(N[(N[(3.0 + N[(2.0 / N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[(x + -1.0), $MachinePrecision] / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(N[(x + 1.0), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\
\;\;\;\;\frac{\left(3 + \frac{2}{{x}^{2}}\right) - \frac{2}{x}}{1 - x}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 x 1))) < 3.99999999999999992e-12

    1. Initial program 8.5%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg8.5%

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

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified8.5%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg8.5%

        \[\leadsto \color{blue}{\frac{-x}{-\left(x + 1\right)}} - \frac{-1 - x}{1 - x} \]
      2. clear-num8.5%

        \[\leadsto \frac{-x}{-\left(x + 1\right)} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub9.7%

        \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\left(x + 1\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}}} \]
      4. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\color{blue}{\left(1 + x\right)}\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      5. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      6. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(\color{blue}{-1} + \left(-x\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      7. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      8. *-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{1 \cdot \left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      9. *-un-lft-identity9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      10. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-\color{blue}{\left(1 + x\right)}\right) \cdot \frac{1 - x}{-1 - x}} \]
      11. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot \frac{1 - x}{-1 - x}} \]
      12. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(\color{blue}{-1} + \left(-x\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      13. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(-1 - x\right)} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr9.7%

      \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 + -1 \cdot x}} \]
    8. Step-by-step derivation
      1. mul-1-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{1 + \color{blue}{\left(-x\right)}} \]
      2. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    9. Simplified9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    10. Taylor expanded in x around inf 99.3%

      \[\leadsto \frac{\color{blue}{\left(3 + 2 \cdot \frac{1}{{x}^{2}}\right) - 2 \cdot \frac{1}{x}}}{1 - x} \]
    11. Step-by-step derivation
      1. associate-*r/99.3%

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

        \[\leadsto \frac{\left(3 + \frac{\color{blue}{2}}{{x}^{2}}\right) - 2 \cdot \frac{1}{x}}{1 - x} \]
      3. associate-*r/99.3%

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

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

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

    if 3.99999999999999992e-12 < (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 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. Step-by-step derivation
      1. clear-num99.9%

        \[\leadsto \color{blue}{\frac{1}{\frac{x + 1}{x}}} - \frac{-1 - x}{1 - x} \]
      2. clear-num99.9%

        \[\leadsto \frac{1}{\frac{x + 1}{x}} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub99.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}}} \]
      4. *-un-lft-identity99.9%

        \[\leadsto \frac{\color{blue}{\frac{1 - x}{-1 - x}} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 100.0%

      \[\leadsto \frac{\frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\color{blue}{1 - \frac{1}{x}}} \]
    8. Step-by-step derivation
      1. div-sub99.9%

        \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 - \frac{1}{x}} - \frac{\frac{x + 1}{x} \cdot 1}{1 - \frac{1}{x}}} \]
      2. sub-neg99.9%

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

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

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

        \[\leadsto \frac{\frac{1 - x}{-1 - x}}{1 + \frac{\color{blue}{-1}}{x}} + \left(-\frac{\frac{x + 1}{x} \cdot 1}{1 - \frac{1}{x}}\right) \]
      6. *-rgt-identity99.9%

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

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

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

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

        \[\leadsto \frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} + \left(-\frac{\frac{1 + x}{x}}{1 + \frac{\color{blue}{-1}}{x}}\right) \]
    9. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} + \left(-\frac{\frac{1 + x}{x}}{1 + \frac{-1}{x}}\right)} \]
    10. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} - \frac{\frac{1 + x}{x}}{1 + \frac{-1}{x}}} \]
      2. div-sub100.0%

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{\left(3 + \frac{2}{{x}^{2}}\right) - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{x + -1}{x + 1} - \frac{x + 1}{x}}{1 + \frac{-1}{x}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.4% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{x + -1}{x + 1} - \frac{x + 1}{x}}{1 + \frac{-1}{x}}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (+ (/ x (+ x 1.0)) (/ (+ x 1.0) (- 1.0 x))) 4e-12)
   (/ (- 3.0 (/ 2.0 x)) (- 1.0 x))
   (/ (- (/ (+ x -1.0) (+ x 1.0)) (/ (+ x 1.0) x)) (+ 1.0 (/ -1.0 x)))))
double code(double x) {
	double tmp;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - x);
	} else {
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((x / (x + 1.0d0)) + ((x + 1.0d0) / (1.0d0 - x))) <= 4d-12) then
        tmp = (3.0d0 - (2.0d0 / x)) / (1.0d0 - x)
    else
        tmp = (((x + (-1.0d0)) / (x + 1.0d0)) - ((x + 1.0d0) / x)) / (1.0d0 + ((-1.0d0) / x))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - x);
	} else {
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if ((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12:
		tmp = (3.0 - (2.0 / x)) / (1.0 - x)
	else:
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x))
	return tmp
function code(x)
	tmp = 0.0
	if (Float64(Float64(x / Float64(x + 1.0)) + Float64(Float64(x + 1.0) / Float64(1.0 - x))) <= 4e-12)
		tmp = Float64(Float64(3.0 - Float64(2.0 / x)) / Float64(1.0 - x));
	else
		tmp = Float64(Float64(Float64(Float64(x + -1.0) / Float64(x + 1.0)) - Float64(Float64(x + 1.0) / x)) / Float64(1.0 + Float64(-1.0 / x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (((x / (x + 1.0)) + ((x + 1.0) / (1.0 - x))) <= 4e-12)
		tmp = (3.0 - (2.0 / x)) / (1.0 - x);
	else
		tmp = (((x + -1.0) / (x + 1.0)) - ((x + 1.0) / x)) / (1.0 + (-1.0 / x));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[N[(N[(x / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(x + 1.0), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 4e-12], N[(N[(3.0 - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[(x + -1.0), $MachinePrecision] / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] - N[(N[(x + 1.0), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[(-1.0 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\
\;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 x 1))) < 3.99999999999999992e-12

    1. Initial program 8.5%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg8.5%

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

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified8.5%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg8.5%

        \[\leadsto \color{blue}{\frac{-x}{-\left(x + 1\right)}} - \frac{-1 - x}{1 - x} \]
      2. clear-num8.5%

        \[\leadsto \frac{-x}{-\left(x + 1\right)} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub9.7%

        \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\left(x + 1\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}}} \]
      4. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\color{blue}{\left(1 + x\right)}\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      5. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      6. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(\color{blue}{-1} + \left(-x\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      7. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      8. *-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{1 \cdot \left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      9. *-un-lft-identity9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      10. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-\color{blue}{\left(1 + x\right)}\right) \cdot \frac{1 - x}{-1 - x}} \]
      11. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot \frac{1 - x}{-1 - x}} \]
      12. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(\color{blue}{-1} + \left(-x\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      13. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(-1 - x\right)} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr9.7%

      \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 + -1 \cdot x}} \]
    8. Step-by-step derivation
      1. mul-1-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{1 + \color{blue}{\left(-x\right)}} \]
      2. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    9. Simplified9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    10. Taylor expanded in x around inf 99.3%

      \[\leadsto \frac{\color{blue}{3 - 2 \cdot \frac{1}{x}}}{1 - x} \]
    11. Step-by-step derivation
      1. associate-*r/99.3%

        \[\leadsto \frac{3 - \color{blue}{\frac{2 \cdot 1}{x}}}{1 - x} \]
      2. metadata-eval99.3%

        \[\leadsto \frac{3 - \frac{\color{blue}{2}}{x}}{1 - x} \]
    12. Simplified99.3%

      \[\leadsto \frac{\color{blue}{3 - \frac{2}{x}}}{1 - x} \]

    if 3.99999999999999992e-12 < (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 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. Step-by-step derivation
      1. clear-num99.9%

        \[\leadsto \color{blue}{\frac{1}{\frac{x + 1}{x}}} - \frac{-1 - x}{1 - x} \]
      2. clear-num99.9%

        \[\leadsto \frac{1}{\frac{x + 1}{x}} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub99.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}}} \]
      4. *-un-lft-identity99.9%

        \[\leadsto \frac{\color{blue}{\frac{1 - x}{-1 - x}} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\frac{x + 1}{x} \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 100.0%

      \[\leadsto \frac{\frac{1 - x}{-1 - x} - \frac{x + 1}{x} \cdot 1}{\color{blue}{1 - \frac{1}{x}}} \]
    8. Step-by-step derivation
      1. div-sub99.9%

        \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 - \frac{1}{x}} - \frac{\frac{x + 1}{x} \cdot 1}{1 - \frac{1}{x}}} \]
      2. sub-neg99.9%

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

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

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

        \[\leadsto \frac{\frac{1 - x}{-1 - x}}{1 + \frac{\color{blue}{-1}}{x}} + \left(-\frac{\frac{x + 1}{x} \cdot 1}{1 - \frac{1}{x}}\right) \]
      6. *-rgt-identity99.9%

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

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

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

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

        \[\leadsto \frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} + \left(-\frac{\frac{1 + x}{x}}{1 + \frac{\color{blue}{-1}}{x}}\right) \]
    9. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} + \left(-\frac{\frac{1 + x}{x}}{1 + \frac{-1}{x}}\right)} \]
    10. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x}}{1 + \frac{-1}{x}} - \frac{\frac{1 + x}{x}}{1 + \frac{-1}{x}}} \]
      2. div-sub100.0%

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

      \[\leadsto \color{blue}{\frac{\frac{1 - x}{-1 - x} - \frac{1 + x}{x}}{1 + \frac{-1}{x}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{x + -1}{x + 1} - \frac{x + 1}{x}}{1 + \frac{-1}{x}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.4% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \mathbf{if}\;t\_0 \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (+ (/ x (+ x 1.0)) (/ (+ x 1.0) (- 1.0 x)))))
   (if (<= t_0 4e-12) (/ (- 3.0 (/ 2.0 x)) (- 1.0 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 <= 4e-12) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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 <= 4d-12) then
        tmp = (3.0d0 - (2.0d0 / x)) / (1.0d0 - 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 <= 4e-12) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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 <= 4e-12:
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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 <= 4e-12)
		tmp = Float64(Float64(3.0 - Float64(2.0 / x)) / Float64(1.0 - 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 <= 4e-12)
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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, 4e-12], N[(N[(3.0 - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $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 4 \cdot 10^{-12}:\\
\;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 x 1))) < 3.99999999999999992e-12

    1. Initial program 8.5%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in8.5%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg8.5%

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

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub08.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg8.5%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified8.5%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg8.5%

        \[\leadsto \color{blue}{\frac{-x}{-\left(x + 1\right)}} - \frac{-1 - x}{1 - x} \]
      2. clear-num8.5%

        \[\leadsto \frac{-x}{-\left(x + 1\right)} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub9.7%

        \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\left(x + 1\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}}} \]
      4. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\color{blue}{\left(1 + x\right)}\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      5. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      6. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(\color{blue}{-1} + \left(-x\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      7. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      8. *-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{1 \cdot \left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      9. *-un-lft-identity9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      10. +-commutative9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-\color{blue}{\left(1 + x\right)}\right) \cdot \frac{1 - x}{-1 - x}} \]
      11. distribute-neg-in9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot \frac{1 - x}{-1 - x}} \]
      12. metadata-eval9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(\color{blue}{-1} + \left(-x\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      13. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(-1 - x\right)} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr9.7%

      \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 + -1 \cdot x}} \]
    8. Step-by-step derivation
      1. mul-1-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{1 + \color{blue}{\left(-x\right)}} \]
      2. sub-neg9.7%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    9. Simplified9.7%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    10. Taylor expanded in x around inf 99.3%

      \[\leadsto \frac{\color{blue}{3 - 2 \cdot \frac{1}{x}}}{1 - x} \]
    11. Step-by-step derivation
      1. associate-*r/99.3%

        \[\leadsto \frac{3 - \color{blue}{\frac{2 \cdot 1}{x}}}{1 - x} \]
      2. metadata-eval99.3%

        \[\leadsto \frac{3 - \frac{\color{blue}{2}}{x}}{1 - x} \]
    12. Simplified99.3%

      \[\leadsto \frac{\color{blue}{3 - \frac{2}{x}}}{1 - x} \]

    if 3.99999999999999992e-12 < (-.f64 (/.f64 x (+.f64 x 1)) (/.f64 (+.f64 x 1) (-.f64 x 1)))

    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 simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{x + 1} + \frac{x + 1}{1 - x} \leq 4 \cdot 10^{-12}:\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{x + 1} + \frac{x + 1}{1 - x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.2% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 0.85\right):\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 0.85)))
   (/ (- 3.0 (/ 2.0 x)) (- 1.0 x))
   (+ 1.0 (* x (+ x 3.0)))))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 0.85)) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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 <= 0.85d0))) then
        tmp = (3.0d0 - (2.0d0 / x)) / (1.0d0 - 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 <= 0.85)) {
		tmp = (3.0 - (2.0 / x)) / (1.0 - x);
	} else {
		tmp = 1.0 + (x * (x + 3.0));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 0.85):
		tmp = (3.0 - (2.0 / x)) / (1.0 - x)
	else:
		tmp = 1.0 + (x * (x + 3.0))
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 0.85))
		tmp = Float64(Float64(3.0 - Float64(2.0 / x)) / Float64(1.0 - 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 <= 0.85)))
		tmp = (3.0 - (2.0 / x)) / (1.0 - 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, 0.85]], $MachinePrecision]], N[(N[(3.0 - N[(2.0 / x), $MachinePrecision]), $MachinePrecision] / N[(1.0 - x), $MachinePrecision]), $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 0.85\right):\\
\;\;\;\;\frac{3 - \frac{2}{x}}{1 - 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 0.849999999999999978 < x

    1. Initial program 9.2%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg29.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified9.2%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg9.2%

        \[\leadsto \color{blue}{\frac{-x}{-\left(x + 1\right)}} - \frac{-1 - x}{1 - x} \]
      2. clear-num9.2%

        \[\leadsto \frac{-x}{-\left(x + 1\right)} - \color{blue}{\frac{1}{\frac{1 - x}{-1 - x}}} \]
      3. frac-sub10.4%

        \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\left(x + 1\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}}} \]
      4. +-commutative10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-\color{blue}{\left(1 + x\right)}\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      5. distribute-neg-in10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      6. metadata-eval10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(\color{blue}{-1} + \left(-x\right)\right) \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      7. sub-neg10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)} \cdot 1}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      8. *-commutative10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{1 \cdot \left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      9. *-un-lft-identity10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \color{blue}{\left(-1 - x\right)}}{\left(-\left(x + 1\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      10. +-commutative10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-\color{blue}{\left(1 + x\right)}\right) \cdot \frac{1 - x}{-1 - x}} \]
      11. distribute-neg-in10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(\left(-1\right) + \left(-x\right)\right)} \cdot \frac{1 - x}{-1 - x}} \]
      12. metadata-eval10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(\color{blue}{-1} + \left(-x\right)\right) \cdot \frac{1 - x}{-1 - x}} \]
      13. sub-neg10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{\left(-1 - x\right)} \cdot \frac{1 - x}{-1 - x}} \]
    6. Applied egg-rr10.4%

      \[\leadsto \color{blue}{\frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \frac{1 - x}{-1 - x}}} \]
    7. Taylor expanded in x around 0 10.4%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 + -1 \cdot x}} \]
    8. Step-by-step derivation
      1. mul-1-neg10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{1 + \color{blue}{\left(-x\right)}} \]
      2. sub-neg10.4%

        \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    9. Simplified10.4%

      \[\leadsto \frac{\left(-x\right) \cdot \frac{1 - x}{-1 - x} - \left(-1 - x\right)}{\color{blue}{1 - x}} \]
    10. Taylor expanded in x around inf 98.8%

      \[\leadsto \frac{\color{blue}{3 - 2 \cdot \frac{1}{x}}}{1 - x} \]
    11. Step-by-step derivation
      1. associate-*r/98.8%

        \[\leadsto \frac{3 - \color{blue}{\frac{2 \cdot 1}{x}}}{1 - x} \]
      2. metadata-eval98.8%

        \[\leadsto \frac{3 - \frac{\color{blue}{2}}{x}}{1 - x} \]
    12. Simplified98.8%

      \[\leadsto \frac{\color{blue}{3 - \frac{2}{x}}}{1 - x} \]

    if -1 < x < 0.849999999999999978

    1. Initial program 100.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg100.0%

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

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

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

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg2100.0%

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

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

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

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

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub0100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub0100.0%

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

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

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

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.1%

      \[\leadsto \color{blue}{1 + \left(3 \cdot x + {x}^{2}\right)} \]
    6. Step-by-step derivation
      1. unpow299.1%

        \[\leadsto 1 + \left(3 \cdot x + \color{blue}{x \cdot x}\right) \]
      2. distribute-rgt-out99.1%

        \[\leadsto 1 + \color{blue}{x \cdot \left(3 + x\right)} \]
    7. Simplified99.1%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 0.85\right):\\ \;\;\;\;\frac{3 - \frac{2}{x}}{1 - x}\\ \mathbf{else}:\\ \;\;\;\;1 + x \cdot \left(x + 3\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 98.7% 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 9.2%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg29.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified9.2%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 97.7%

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

    if -1 < x < 1

    1. Initial program 100.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg100.0%

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

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

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

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg2100.0%

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

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

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

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

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub0100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub0100.0%

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

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

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

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 99.1%

      \[\leadsto \color{blue}{1 + \left(3 \cdot x + {x}^{2}\right)} \]
    6. Step-by-step derivation
      1. unpow299.1%

        \[\leadsto 1 + \left(3 \cdot x + \color{blue}{x \cdot x}\right) \]
      2. distribute-rgt-out99.1%

        \[\leadsto 1 + \color{blue}{x \cdot \left(3 + x\right)} \]
    7. Simplified99.1%

      \[\leadsto \color{blue}{1 + x \cdot \left(3 + x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.5%

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

Alternative 6: 98.6% 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 9.2%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg29.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified9.2%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 97.7%

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

    if -1 < x < 1

    1. Initial program 100.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg100.0%

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

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

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

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg2100.0%

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

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

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

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

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub0100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub0100.0%

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

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

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

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 98.9%

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

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

Alternative 7: 98.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1 \lor \neg \left(x \leq 1\right):\\ \;\;\;\;\frac{-3}{x}\\ \mathbf{else}:\\ \;\;\;\;x + 1\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (or (<= x -1.0) (not (<= x 1.0))) (/ -3.0 x) (+ x 1.0)))
double code(double x) {
	double tmp;
	if ((x <= -1.0) || !(x <= 1.0)) {
		tmp = -3.0 / x;
	} else {
		tmp = x + 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 = x + 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 = x + 1.0;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x <= -1.0) or not (x <= 1.0):
		tmp = -3.0 / x
	else:
		tmp = x + 1.0
	return tmp
function code(x)
	tmp = 0.0
	if ((x <= -1.0) || !(x <= 1.0))
		tmp = Float64(-3.0 / x);
	else
		tmp = Float64(x + 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 = x + 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], N[(x + 1.0), $MachinePrecision]]
\begin{array}{l}

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

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


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

    1. Initial program 9.2%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
      2. distribute-neg-frac9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
      3. distribute-neg-in9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
      4. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg29.2%

        \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
      6. sub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
      7. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
      8. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
      9. metadata-eval9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub09.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
      13. +-commutative9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
      14. unsub-neg9.2%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
    3. Simplified9.2%

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 97.7%

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

    if -1 < x < 1

    1. Initial program 100.0%

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
    2. Step-by-step derivation
      1. remove-double-neg100.0%

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

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

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

        \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
      5. distribute-frac-neg2100.0%

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

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

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

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

        \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
      10. neg-sub0100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
      11. associate-+l-100.0%

        \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
      12. neg-sub0100.0%

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

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

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

      \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 98.9%

      \[\leadsto \color{blue}{x} - \frac{-1 - x}{1 - x} \]
    6. Taylor expanded in x around 0 98.5%

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

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

Alternative 8: 51.6% 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 58.9%

    \[\frac{x}{x + 1} - \frac{x + 1}{x - 1} \]
  2. Step-by-step derivation
    1. remove-double-neg58.9%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\left(-\left(-\frac{x + 1}{x - 1}\right)\right)} \]
    2. distribute-neg-frac58.9%

      \[\leadsto \frac{x}{x + 1} - \left(-\color{blue}{\frac{-\left(x + 1\right)}{x - 1}}\right) \]
    3. distribute-neg-in58.9%

      \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{x - 1}\right) \]
    4. sub-neg58.9%

      \[\leadsto \frac{x}{x + 1} - \left(-\frac{\color{blue}{\left(-x\right) - 1}}{x - 1}\right) \]
    5. distribute-frac-neg258.9%

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{\left(-x\right) - 1}{-\left(x - 1\right)}} \]
    6. sub-neg58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-x\right) + \left(-1\right)}}{-\left(x - 1\right)} \]
    7. +-commutative58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) + \left(-x\right)}}{-\left(x - 1\right)} \]
    8. unsub-neg58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{\left(-1\right) - x}}{-\left(x - 1\right)} \]
    9. metadata-eval58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{-1} - x}{-\left(x - 1\right)} \]
    10. neg-sub058.9%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{0 - \left(x - 1\right)}} \]
    11. associate-+l-58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(0 - x\right) + 1}} \]
    12. neg-sub058.9%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{\left(-x\right)} + 1} \]
    13. +-commutative58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 + \left(-x\right)}} \]
    14. unsub-neg58.9%

      \[\leadsto \frac{x}{x + 1} - \frac{-1 - x}{\color{blue}{1 - x}} \]
  3. Simplified58.9%

    \[\leadsto \color{blue}{\frac{x}{x + 1} - \frac{-1 - x}{1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 55.4%

    \[\leadsto \color{blue}{1} \]
  6. Final simplification55.4%

    \[\leadsto 1 \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024039 
(FPCore (x)
  :name "Asymptote C"
  :precision binary64
  (- (/ x (+ x 1.0)) (/ (+ x 1.0) (- x 1.0))))