Asymptote A

Percentage Accurate: 77.5% → 99.9%
Time: 7.3s
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?

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

\\
\frac{\frac{-2}{x\_m + 1}}{x\_m + -1}
\end{array}
Derivation
  1. Initial program 78.0%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative78.0%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac278.0%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-78.0%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac278.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative78.0%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg78.0%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac78.0%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
  7. Simplified99.6%

    \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
  8. Step-by-step derivation
    1. associate-/r*99.9%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x + 1}}{x + -1}} \]
    2. metadata-eval99.9%

      \[\leadsto \frac{\frac{-2}{x + 1}}{x + \color{blue}{\left(-1\right)}} \]
    3. sub-neg99.9%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\color{blue}{x - 1}} \]
    4. flip--99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\color{blue}{\frac{x \cdot x - 1 \cdot 1}{x + 1}}} \]
    5. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - \color{blue}{1}}{x + 1}} \]
    6. difference-of-sqr-199.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\color{blue}{\left(x + 1\right) \cdot \left(x - 1\right)}}{x + 1}} \]
    7. sub-neg99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\left(x + 1\right) \cdot \color{blue}{\left(x + \left(-1\right)\right)}}{x + 1}} \]
    8. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\left(x + 1\right) \cdot \left(x + \color{blue}{-1}\right)}{x + 1}} \]
    9. associate-/r/93.1%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x + 1}}{\left(x + 1\right) \cdot \left(x + -1\right)} \cdot \left(x + 1\right)} \]
    10. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1 + x}}}{\left(x + 1\right) \cdot \left(x + -1\right)} \cdot \left(x + 1\right) \]
    11. metadata-eval93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\left(x + 1\right) \cdot \left(x + \color{blue}{\left(-1\right)}\right)} \cdot \left(x + 1\right) \]
    12. sub-neg93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\left(x + 1\right) \cdot \color{blue}{\left(x - 1\right)}} \cdot \left(x + 1\right) \]
    13. difference-of-sqr-193.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\color{blue}{x \cdot x - 1}} \cdot \left(x + 1\right) \]
    14. fma-neg93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \cdot \left(x + 1\right) \]
    15. metadata-eval93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \cdot \left(x + 1\right) \]
    16. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \color{blue}{\left(1 + x\right)} \]
  9. Applied egg-rr93.1%

    \[\leadsto \color{blue}{\frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right)} \]
  10. Step-by-step derivation
    1. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{\color{blue}{x + 1}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    2. lft-mult-inverse93.0%

      \[\leadsto \frac{\frac{-2}{x + \color{blue}{\frac{1}{x} \cdot x}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    3. *-un-lft-identity93.0%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1 \cdot x} + \frac{1}{x} \cdot x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    4. distribute-rgt-in93.0%

      \[\leadsto \frac{\frac{-2}{\color{blue}{x \cdot \left(1 + \frac{1}{x}\right)}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    5. associate-/r/99.5%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x \cdot \left(1 + \frac{1}{x}\right)}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}}} \]
    6. distribute-rgt-in99.5%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1 \cdot x + \frac{1}{x} \cdot x}}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    7. *-un-lft-identity99.5%

      \[\leadsto \frac{\frac{-2}{\color{blue}{x} + \frac{1}{x} \cdot x}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    8. lft-mult-inverse99.6%

      \[\leadsto \frac{\frac{-2}{x + \color{blue}{1}}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    9. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)}{1 + x}} \]
    10. fma-neg99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\color{blue}{x \cdot x - 1}}{1 + x}} \]
    11. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - \color{blue}{-1 \cdot -1}}{1 + x}} \]
    12. +-commutative99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - -1 \cdot -1}{\color{blue}{x + 1}}} \]
    13. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - -1 \cdot -1}{x + \color{blue}{\left(--1\right)}}} \]
    14. sub-neg99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - -1 \cdot -1}{\color{blue}{x - -1}}} \]
    15. flip-+99.9%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\color{blue}{x + -1}} \]
  11. Applied egg-rr99.9%

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

Alternative 2: 98.3% accurate, 0.9× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 0.75:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{-2}{x\_m}}{x\_m + -1}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= x_m 0.75) 2.0 (/ (/ -2.0 x_m) (+ x_m -1.0))))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 0.75) {
		tmp = 2.0;
	} else {
		tmp = (-2.0 / x_m) / (x_m + -1.0);
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (x_m <= 0.75d0) then
        tmp = 2.0d0
    else
        tmp = ((-2.0d0) / x_m) / (x_m + (-1.0d0))
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (x_m <= 0.75) {
		tmp = 2.0;
	} else {
		tmp = (-2.0 / x_m) / (x_m + -1.0);
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 0.75:
		tmp = 2.0
	else:
		tmp = (-2.0 / x_m) / (x_m + -1.0)
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 0.75)
		tmp = 2.0;
	else
		tmp = Float64(Float64(-2.0 / x_m) / Float64(x_m + -1.0));
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (x_m <= 0.75)
		tmp = 2.0;
	else
		tmp = (-2.0 / x_m) / (x_m + -1.0);
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[x$95$m, 0.75], 2.0, N[(N[(-2.0 / x$95$m), $MachinePrecision] / N[(x$95$m + -1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 0.75:\\
\;\;\;\;2\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.75

    1. Initial program 85.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.3%

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

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 64.0%

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

    if 0.75 < x

    1. Initial program 58.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative58.3%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac258.3%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-58.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg58.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg58.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac258.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative58.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg58.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval58.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac58.3%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval58.3%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr58.3%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
    7. Simplified98.8%

      \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    8. Taylor expanded in x around inf 97.6%

      \[\leadsto \frac{-2}{\color{blue}{x} \cdot \left(x + -1\right)} \]
    9. Step-by-step derivation
      1. associate-/r*98.6%

        \[\leadsto \color{blue}{\frac{\frac{-2}{x}}{x + -1}} \]
      2. div-inv98.3%

        \[\leadsto \color{blue}{\frac{-2}{x} \cdot \frac{1}{x + -1}} \]
    10. Applied egg-rr98.3%

      \[\leadsto \color{blue}{\frac{-2}{x} \cdot \frac{1}{x + -1}} \]
    11. Step-by-step derivation
      1. associate-*r/98.6%

        \[\leadsto \color{blue}{\frac{\frac{-2}{x} \cdot 1}{x + -1}} \]
      2. *-rgt-identity98.6%

        \[\leadsto \frac{\color{blue}{\frac{-2}{x}}}{x + -1} \]
    12. Simplified98.6%

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

Alternative 3: 97.8% accurate, 0.9× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 0.75:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x\_m \cdot \left(x\_m + -1\right)}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= x_m 0.75) 2.0 (/ -2.0 (* x_m (+ x_m -1.0)))))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 0.75) {
		tmp = 2.0;
	} else {
		tmp = -2.0 / (x_m * (x_m + -1.0));
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (x_m <= 0.75d0) then
        tmp = 2.0d0
    else
        tmp = (-2.0d0) / (x_m * (x_m + (-1.0d0)))
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (x_m <= 0.75) {
		tmp = 2.0;
	} else {
		tmp = -2.0 / (x_m * (x_m + -1.0));
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 0.75:
		tmp = 2.0
	else:
		tmp = -2.0 / (x_m * (x_m + -1.0))
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 0.75)
		tmp = 2.0;
	else
		tmp = Float64(-2.0 / Float64(x_m * Float64(x_m + -1.0)));
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (x_m <= 0.75)
		tmp = 2.0;
	else
		tmp = -2.0 / (x_m * (x_m + -1.0));
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[x$95$m, 0.75], 2.0, N[(-2.0 / N[(x$95$m * N[(x$95$m + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 0.75:\\
\;\;\;\;2\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.75

    1. Initial program 85.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.3%

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

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 64.0%

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

    if 0.75 < x

    1. Initial program 58.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative58.3%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac258.3%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-58.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg58.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg58.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac258.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative58.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg58.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval58.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac58.3%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval58.3%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr58.3%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
    7. Simplified98.8%

      \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    8. Taylor expanded in x around inf 97.6%

      \[\leadsto \frac{-2}{\color{blue}{x} \cdot \left(x + -1\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 4: 52.5% accurate, 1.1× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{1}{x\_m}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (if (<= x_m 1.0) 2.0 (* -2.0 (/ 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 * (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) * (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 * (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 * (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(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 * (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[(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}:\\
\;\;\;\;-2 \cdot \frac{1}{x\_m}\\


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

    1. Initial program 85.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative85.3%

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

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-85.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub085.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in85.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg85.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg85.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative85.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg85.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg85.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval85.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 64.0%

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

    if 1 < x

    1. Initial program 58.3%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative58.3%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac258.3%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-58.3%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub058.3%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg58.3%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg58.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac258.3%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative58.3%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg58.3%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg58.3%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval58.3%

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

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg58.3%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac58.3%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval58.3%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr58.3%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
    7. Simplified98.8%

      \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    8. Taylor expanded in x around inf 97.6%

      \[\leadsto \frac{-2}{\color{blue}{x} \cdot \left(x + -1\right)} \]
    9. Taylor expanded in x around 0 4.8%

      \[\leadsto \color{blue}{\frac{2}{x}} \]
    10. Step-by-step derivation
      1. add-sqr-sqrt4.8%

        \[\leadsto \color{blue}{\sqrt{\frac{2}{x}} \cdot \sqrt{\frac{2}{x}}} \]
      2. sqrt-unprod53.5%

        \[\leadsto \color{blue}{\sqrt{\frac{2}{x} \cdot \frac{2}{x}}} \]
      3. frac-times55.4%

        \[\leadsto \sqrt{\color{blue}{\frac{2 \cdot 2}{x \cdot x}}} \]
      4. metadata-eval55.4%

        \[\leadsto \sqrt{\frac{\color{blue}{4}}{x \cdot x}} \]
      5. metadata-eval55.4%

        \[\leadsto \sqrt{\frac{\color{blue}{-2 \cdot -2}}{x \cdot x}} \]
      6. frac-times53.5%

        \[\leadsto \sqrt{\color{blue}{\frac{-2}{x} \cdot \frac{-2}{x}}} \]
      7. sqrt-unprod0.0%

        \[\leadsto \color{blue}{\sqrt{\frac{-2}{x}} \cdot \sqrt{\frac{-2}{x}}} \]
      8. add-sqr-sqrt6.8%

        \[\leadsto \color{blue}{\frac{-2}{x}} \]
      9. clear-num6.8%

        \[\leadsto \color{blue}{\frac{1}{\frac{x}{-2}}} \]
      10. associate-/r/6.8%

        \[\leadsto \color{blue}{\frac{1}{x} \cdot -2} \]
    11. Applied egg-rr6.8%

      \[\leadsto \color{blue}{\frac{1}{x} \cdot -2} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification48.6%

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

Alternative 5: 99.9% accurate, 1.2× speedup?

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

\\
\frac{\frac{-2}{x\_m + -1}}{x\_m + 1}
\end{array}
Derivation
  1. Initial program 78.0%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative78.0%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac278.0%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-78.0%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac278.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative78.0%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg78.0%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac78.0%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
  7. Simplified99.6%

    \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
  8. Step-by-step derivation
    1. associate-/r*99.9%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x + 1}}{x + -1}} \]
    2. metadata-eval99.9%

      \[\leadsto \frac{\frac{-2}{x + 1}}{x + \color{blue}{\left(-1\right)}} \]
    3. sub-neg99.9%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\color{blue}{x - 1}} \]
    4. flip--99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\color{blue}{\frac{x \cdot x - 1 \cdot 1}{x + 1}}} \]
    5. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{x \cdot x - \color{blue}{1}}{x + 1}} \]
    6. difference-of-sqr-199.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\color{blue}{\left(x + 1\right) \cdot \left(x - 1\right)}}{x + 1}} \]
    7. sub-neg99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\left(x + 1\right) \cdot \color{blue}{\left(x + \left(-1\right)\right)}}{x + 1}} \]
    8. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{x + 1}}{\frac{\left(x + 1\right) \cdot \left(x + \color{blue}{-1}\right)}{x + 1}} \]
    9. associate-/r/93.1%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x + 1}}{\left(x + 1\right) \cdot \left(x + -1\right)} \cdot \left(x + 1\right)} \]
    10. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1 + x}}}{\left(x + 1\right) \cdot \left(x + -1\right)} \cdot \left(x + 1\right) \]
    11. metadata-eval93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\left(x + 1\right) \cdot \left(x + \color{blue}{\left(-1\right)}\right)} \cdot \left(x + 1\right) \]
    12. sub-neg93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\left(x + 1\right) \cdot \color{blue}{\left(x - 1\right)}} \cdot \left(x + 1\right) \]
    13. difference-of-sqr-193.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\color{blue}{x \cdot x - 1}} \cdot \left(x + 1\right) \]
    14. fma-neg93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \cdot \left(x + 1\right) \]
    15. metadata-eval93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \cdot \left(x + 1\right) \]
    16. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \color{blue}{\left(1 + x\right)} \]
  9. Applied egg-rr93.1%

    \[\leadsto \color{blue}{\frac{\frac{-2}{1 + x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right)} \]
  10. Step-by-step derivation
    1. +-commutative93.1%

      \[\leadsto \frac{\frac{-2}{\color{blue}{x + 1}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    2. lft-mult-inverse93.0%

      \[\leadsto \frac{\frac{-2}{x + \color{blue}{\frac{1}{x} \cdot x}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    3. *-un-lft-identity93.0%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1 \cdot x} + \frac{1}{x} \cdot x}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    4. distribute-rgt-in93.0%

      \[\leadsto \frac{\frac{-2}{\color{blue}{x \cdot \left(1 + \frac{1}{x}\right)}}}{\mathsf{fma}\left(x, x, -1\right)} \cdot \left(1 + x\right) \]
    5. associate-/r/99.5%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x \cdot \left(1 + \frac{1}{x}\right)}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}}} \]
    6. +-commutative99.5%

      \[\leadsto \frac{\frac{-2}{x \cdot \color{blue}{\left(\frac{1}{x} + 1\right)}}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    7. distribute-rgt-in99.5%

      \[\leadsto \frac{\frac{-2}{\color{blue}{\frac{1}{x} \cdot x + 1 \cdot x}}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    8. lft-mult-inverse99.6%

      \[\leadsto \frac{\frac{-2}{\color{blue}{1} + 1 \cdot x}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    9. *-un-lft-identity99.6%

      \[\leadsto \frac{\frac{-2}{1 + \color{blue}{x}}}{\frac{\mathsf{fma}\left(x, x, -1\right)}{1 + x}} \]
    10. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)}{1 + x}} \]
    11. fma-neg99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{\color{blue}{x \cdot x - 1}}{1 + x}} \]
    12. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{x \cdot x - \color{blue}{-1 \cdot -1}}{1 + x}} \]
    13. +-commutative99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{x \cdot x - -1 \cdot -1}{\color{blue}{x + 1}}} \]
    14. metadata-eval99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{x \cdot x - -1 \cdot -1}{x + \color{blue}{\left(--1\right)}}} \]
    15. sub-neg99.6%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\frac{x \cdot x - -1 \cdot -1}{\color{blue}{x - -1}}} \]
    16. flip-+99.9%

      \[\leadsto \frac{\frac{-2}{1 + x}}{\color{blue}{x + -1}} \]
    17. associate-/l/99.6%

      \[\leadsto \color{blue}{\frac{-2}{\left(x + -1\right) \cdot \left(1 + x\right)}} \]
    18. associate-/r*99.9%

      \[\leadsto \color{blue}{\frac{\frac{-2}{x + -1}}{1 + x}} \]
    19. +-commutative99.9%

      \[\leadsto \frac{\frac{-2}{x + -1}}{\color{blue}{x + 1}} \]
  11. Applied egg-rr99.9%

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

Alternative 6: 99.4% accurate, 1.2× speedup?

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

\\
\frac{-2}{\left(x\_m + 1\right) \cdot \left(x\_m + -1\right)}
\end{array}
Derivation
  1. Initial program 78.0%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative78.0%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac278.0%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-78.0%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac278.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative78.0%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg78.0%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac78.0%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
  7. Simplified99.6%

    \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
  8. Add Preprocessing

Alternative 7: 50.4% 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 78.0%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative78.0%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac278.0%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-78.0%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac278.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative78.0%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg78.0%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 47.5%

    \[\leadsto \color{blue}{2} \]
  6. Add Preprocessing

Alternative 8: 10.7% 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 78.0%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative78.0%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac278.0%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-78.0%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub078.0%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg78.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac278.0%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg78.0%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative78.0%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg78.0%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval78.0%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 46.9%

    \[\leadsto \frac{1}{1 - x} - \color{blue}{-1} \]
  6. Taylor expanded in x around inf 10.2%

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

Reproduce

?
herbie shell --seed 2024129 
(FPCore (x)
  :name "Asymptote A"
  :precision binary64
  (- (/ 1.0 (+ x 1.0)) (/ 1.0 (- x 1.0))))