Asymptote A

Percentage Accurate: 77.5% → 99.9%
Time: 10.2s
Alternatives: 8
Speedup: 1.2×

Specification

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

\\
\frac{1}{x + 1} - \frac{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: 77.5% accurate, 1.0× speedup?

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

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

Alternative 1: 99.9% accurate, 1.2× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \frac{\frac{-2}{1 - x\_m}}{-1 - x\_m} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (/ (/ -2.0 (- 1.0 x_m)) (- -1.0 x_m)))
x_m = fabs(x);
double code(double x_m) {
	return (-2.0 / (1.0 - x_m)) / (-1.0 - x_m);
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = ((-2.0d0) / (1.0d0 - x_m)) / ((-1.0d0) - x_m)
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return (-2.0 / (1.0 - x_m)) / (-1.0 - x_m);
}
x_m = math.fabs(x)
def code(x_m):
	return (-2.0 / (1.0 - x_m)) / (-1.0 - x_m)
x_m = abs(x)
function code(x_m)
	return Float64(Float64(-2.0 / Float64(1.0 - x_m)) / Float64(-1.0 - x_m))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = (-2.0 / (1.0 - x_m)) / (-1.0 - x_m);
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(N[(-2.0 / N[(1.0 - x$95$m), $MachinePrecision]), $MachinePrecision] / N[(-1.0 - x$95$m), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
\frac{\frac{-2}{1 - x\_m}}{-1 - x\_m}
\end{array}
Derivation
  1. Initial program 76.3%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative76.3%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac276.3%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-76.3%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac276.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative76.3%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg76.3%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified76.3%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub76.6%

      \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. *-rgt-identity76.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
    3. metadata-eval76.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
    4. div-inv76.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
    5. associate-/r*76.6%

      \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
    6. metadata-eval76.6%

      \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    7. div-inv76.6%

      \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    8. *-un-lft-identity76.6%

      \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
    9. associate--l-79.8%

      \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
    10. div-inv79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    11. metadata-eval79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    12. *-rgt-identity79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    13. div-inv79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
    14. metadata-eval79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
    15. *-rgt-identity79.8%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
  6. Applied egg-rr79.8%

    \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
  7. Step-by-step derivation
    1. div-sub79.8%

      \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} - \frac{x + \left(1 - x\right)}{1 - x}}}{-1 - x} \]
    2. sub-neg79.8%

      \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}}{-1 - x} \]
  8. Applied egg-rr79.8%

    \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}}{-1 - x} \]
  9. Step-by-step derivation
    1. sub-neg79.8%

      \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} - \frac{x + \left(1 - x\right)}{1 - x}}}{-1 - x} \]
    2. div-sub79.8%

      \[\leadsto \frac{\color{blue}{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}}{-1 - x} \]
    3. +-commutative79.8%

      \[\leadsto \frac{\frac{-1 - \color{blue}{\left(\left(1 - x\right) + x\right)}}{1 - x}}{-1 - x} \]
    4. associate--r-99.8%

      \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
    5. +-inverses99.8%

      \[\leadsto \frac{\frac{-1 - \left(1 - \color{blue}{0}\right)}{1 - x}}{-1 - x} \]
    6. metadata-eval99.8%

      \[\leadsto \frac{\frac{-1 - \color{blue}{1}}{1 - x}}{-1 - x} \]
    7. metadata-eval99.8%

      \[\leadsto \frac{\frac{\color{blue}{-2}}{1 - x}}{-1 - x} \]
  10. Simplified99.8%

    \[\leadsto \frac{\color{blue}{\frac{-2}{1 - x}}}{-1 - x} \]
  11. Final simplification99.8%

    \[\leadsto \frac{\frac{-2}{1 - x}}{-1 - x} \]
  12. Add Preprocessing

Alternative 2: 97.9% accurate, 0.9× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{2}{x\_m \cdot \left(-1 - x\_m\right)}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= x_m 1.0) 2.0 (/ 2.0 (* x_m (- -1.0 x_m)))))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = 2.0 / (x_m * (-1.0 - x_m));
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (x_m <= 1.0d0) then
        tmp = 2.0d0
    else
        tmp = 2.0d0 / (x_m * ((-1.0d0) - x_m))
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = 2.0 / (x_m * (-1.0 - x_m));
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 1.0:
		tmp = 2.0
	else:
		tmp = 2.0 / (x_m * (-1.0 - x_m))
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = Float64(2.0 / Float64(x_m * Float64(-1.0 - x_m)));
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = 2.0 / (x_m * (-1.0 - x_m));
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[x$95$m, 1.0], 2.0, N[(2.0 / N[(x$95$m * N[(-1.0 - x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 1:\\
\;\;\;\;2\\

\mathbf{else}:\\
\;\;\;\;\frac{2}{x\_m \cdot \left(-1 - x\_m\right)}\\


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

    1. Initial program 85.0%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.0%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac285.0%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.0%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac285.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.0%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.0%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified85.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 69.4%

      \[\leadsto \color{blue}{2} \]

    if 1 < x

    1. Initial program 51.4%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative51.4%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac251.4%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-51.4%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac251.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative51.4%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg51.4%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified51.4%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub52.5%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*52.5%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. metadata-eval52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      7. div-inv52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. *-un-lft-identity52.5%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-58.7%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr58.7%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Taylor expanded in x around inf 98.6%

      \[\leadsto \frac{\color{blue}{\frac{2}{x}}}{-1 - x} \]
    8. Step-by-step derivation
      1. *-un-lft-identity98.6%

        \[\leadsto \color{blue}{1 \cdot \frac{\frac{2}{x}}{-1 - x}} \]
    9. Applied egg-rr98.6%

      \[\leadsto \color{blue}{1 \cdot \frac{\frac{2}{x}}{-1 - x}} \]
    10. Step-by-step derivation
      1. *-lft-identity98.6%

        \[\leadsto \color{blue}{\frac{\frac{2}{x}}{-1 - x}} \]
      2. associate-/r*97.8%

        \[\leadsto \color{blue}{\frac{2}{x \cdot \left(-1 - x\right)}} \]
    11. Simplified97.8%

      \[\leadsto \color{blue}{\frac{2}{x \cdot \left(-1 - x\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification76.8%

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

Alternative 3: 98.4% accurate, 0.9× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{2}{x\_m}}{-1 - x\_m}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= x_m 1.0) 2.0 (/ (/ 2.0 x_m) (- -1.0 x_m))))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = (2.0 / x_m) / (-1.0 - x_m);
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (x_m <= 1.0d0) then
        tmp = 2.0d0
    else
        tmp = (2.0d0 / x_m) / ((-1.0d0) - x_m)
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = (2.0 / x_m) / (-1.0 - x_m);
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 1.0:
		tmp = 2.0
	else:
		tmp = (2.0 / x_m) / (-1.0 - x_m)
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = Float64(Float64(2.0 / x_m) / Float64(-1.0 - x_m));
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = (2.0 / x_m) / (-1.0 - x_m);
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[x$95$m, 1.0], 2.0, N[(N[(2.0 / x$95$m), $MachinePrecision] / N[(-1.0 - x$95$m), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 1:\\
\;\;\;\;2\\

\mathbf{else}:\\
\;\;\;\;\frac{\frac{2}{x\_m}}{-1 - x\_m}\\


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

    1. Initial program 85.0%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.0%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac285.0%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.0%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac285.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.0%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.0%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified85.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 69.4%

      \[\leadsto \color{blue}{2} \]

    if 1 < x

    1. Initial program 51.4%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative51.4%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac251.4%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-51.4%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac251.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative51.4%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg51.4%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified51.4%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub52.5%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*52.5%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. metadata-eval52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      7. div-inv52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. *-un-lft-identity52.5%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-58.7%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr58.7%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Taylor expanded in x around inf 98.6%

      \[\leadsto \frac{\color{blue}{\frac{2}{x}}}{-1 - x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification77.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{2}{x}}{-1 - x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.4% accurate, 1.2× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \frac{-2}{\left(1 - x\_m\right) \cdot \left(-1 - x\_m\right)} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (/ -2.0 (* (- 1.0 x_m) (- -1.0 x_m))))
x_m = fabs(x);
double code(double x_m) {
	return -2.0 / ((1.0 - x_m) * (-1.0 - x_m));
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = (-2.0d0) / ((1.0d0 - x_m) * ((-1.0d0) - x_m))
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return -2.0 / ((1.0 - x_m) * (-1.0 - x_m));
}
x_m = math.fabs(x)
def code(x_m):
	return -2.0 / ((1.0 - x_m) * (-1.0 - x_m))
x_m = abs(x)
function code(x_m)
	return Float64(-2.0 / Float64(Float64(1.0 - x_m) * Float64(-1.0 - x_m)))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = -2.0 / ((1.0 - x_m) * (-1.0 - x_m));
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(-2.0 / N[(N[(1.0 - x$95$m), $MachinePrecision] * N[(-1.0 - x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
\frac{-2}{\left(1 - x\_m\right) \cdot \left(-1 - x\_m\right)}
\end{array}
Derivation
  1. Initial program 76.3%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative76.3%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac276.3%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-76.3%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac276.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative76.3%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg76.3%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified76.3%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac76.3%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr76.3%

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

    \[\leadsto \color{blue}{\frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
  8. Final simplification99.7%

    \[\leadsto \frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)} \]
  9. Add Preprocessing

Alternative 5: 53.2% accurate, 1.4× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x\_m}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (if (<= x_m 1.0) 2.0 (/ -2.0 x_m)))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = -2.0 / x_m;
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (x_m <= 1.0d0) then
        tmp = 2.0d0
    else
        tmp = (-2.0d0) / x_m
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (x_m <= 1.0) {
		tmp = 2.0;
	} else {
		tmp = -2.0 / x_m;
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 1.0:
		tmp = 2.0
	else:
		tmp = -2.0 / x_m
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = Float64(-2.0 / x_m);
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (x_m <= 1.0)
		tmp = 2.0;
	else
		tmp = -2.0 / x_m;
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[x$95$m, 1.0], 2.0, N[(-2.0 / x$95$m), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 1:\\
\;\;\;\;2\\

\mathbf{else}:\\
\;\;\;\;\frac{-2}{x\_m}\\


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

    1. Initial program 85.0%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.0%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac285.0%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.0%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.0%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac285.0%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.0%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.0%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.0%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.0%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified85.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 69.4%

      \[\leadsto \color{blue}{2} \]

    if 1 < x

    1. Initial program 51.4%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative51.4%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac251.4%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-51.4%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub051.4%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg51.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac251.4%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg51.4%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative51.4%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg51.4%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval51.4%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified51.4%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub52.5%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv52.5%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*52.5%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. metadata-eval52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      7. div-inv52.5%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. *-un-lft-identity52.5%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-58.7%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity58.7%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr58.7%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Taylor expanded in x around inf 98.6%

      \[\leadsto \frac{\color{blue}{\frac{2}{x}}}{-1 - x} \]
    8. Taylor expanded in x around 0 6.6%

      \[\leadsto \color{blue}{\frac{-2}{x}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification53.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 2.9% accurate, 11.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ -2 \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 -2.0)
x_m = fabs(x);
double code(double x_m) {
	return -2.0;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = -2.0d0
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return -2.0;
}
x_m = math.fabs(x)
def code(x_m):
	return -2.0
x_m = abs(x)
function code(x_m)
	return -2.0
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = -2.0;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := -2.0
\begin{array}{l}
x_m = \left|x\right|

\\
-2
\end{array}
Derivation
  1. Initial program 76.3%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative76.3%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac276.3%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-76.3%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac276.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative76.3%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg76.3%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified76.3%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac76.3%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr76.3%

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

    \[\leadsto \color{blue}{\frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
  8. Step-by-step derivation
    1. div-inv99.7%

      \[\leadsto \color{blue}{-2 \cdot \frac{1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. inv-pow99.7%

      \[\leadsto -2 \cdot \color{blue}{{\left(\left(1 - x\right) \cdot \left(-1 - x\right)\right)}^{-1}} \]
  9. Applied egg-rr48.4%

    \[\leadsto \color{blue}{-2 \cdot {\left(-1 - x\right)}^{-2}} \]
  10. Step-by-step derivation
    1. *-commutative48.4%

      \[\leadsto \color{blue}{{\left(-1 - x\right)}^{-2} \cdot -2} \]
  11. Simplified48.4%

    \[\leadsto \color{blue}{{\left(-1 - x\right)}^{-2} \cdot -2} \]
  12. Taylor expanded in x around 0 2.9%

    \[\leadsto \color{blue}{-2} \]
  13. Final simplification2.9%

    \[\leadsto -2 \]
  14. Add Preprocessing

Alternative 7: 10.8% accurate, 11.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ 1 \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 1.0)
x_m = fabs(x);
double code(double x_m) {
	return 1.0;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = 1.0d0
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return 1.0;
}
x_m = math.fabs(x)
def code(x_m):
	return 1.0
x_m = abs(x)
function code(x_m)
	return 1.0
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = 1.0;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := 1.0
\begin{array}{l}
x_m = \left|x\right|

\\
1
\end{array}
Derivation
  1. Initial program 76.3%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative76.3%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac276.3%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-76.3%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac276.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative76.3%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg76.3%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified76.3%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 51.6%

    \[\leadsto \frac{1}{1 - x} - \color{blue}{-1} \]
  6. Taylor expanded in x around inf 11.0%

    \[\leadsto \color{blue}{1} \]
  7. Final simplification11.0%

    \[\leadsto 1 \]
  8. Add Preprocessing

Alternative 8: 51.1% accurate, 11.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ 2 \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 2.0)
x_m = fabs(x);
double code(double x_m) {
	return 2.0;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = 2.0d0
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return 2.0;
}
x_m = math.fabs(x)
def code(x_m):
	return 2.0
x_m = abs(x)
function code(x_m)
	return 2.0
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = 2.0;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := 2.0
\begin{array}{l}
x_m = \left|x\right|

\\
2
\end{array}
Derivation
  1. Initial program 76.3%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative76.3%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac276.3%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-76.3%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub076.3%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg76.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac276.3%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg76.3%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative76.3%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg76.3%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval76.3%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified76.3%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 52.2%

    \[\leadsto \color{blue}{2} \]
  6. Final simplification52.2%

    \[\leadsto 2 \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024071 
(FPCore (x)
  :name "Asymptote A"
  :precision binary64
  (- (/ 1.0 (+ x 1.0)) (/ 1.0 (- x 1.0))))