Asymptote A

Percentage Accurate: 77.8% → 99.9%
Time: 6.8s
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: 77.8% 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, 0.7× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \frac{\frac{-1 - \left(1 + \left(x_m - x_m\right)\right)}{1 - x_m}}{-1 - x_m} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (/ (/ (- -1.0 (+ 1.0 (- x_m x_m))) (- 1.0 x_m)) (- -1.0 x_m)))
x_m = fabs(x);
double code(double x_m) {
	return ((-1.0 - (1.0 + (x_m - x_m))) / (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 = (((-1.0d0) - (1.0d0 + (x_m - x_m))) / (1.0d0 - x_m)) / ((-1.0d0) - x_m)
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return ((-1.0 - (1.0 + (x_m - x_m))) / (1.0 - x_m)) / (-1.0 - x_m);
}
x_m = math.fabs(x)
def code(x_m):
	return ((-1.0 - (1.0 + (x_m - x_m))) / (1.0 - x_m)) / (-1.0 - x_m)
x_m = abs(x)
function code(x_m)
	return Float64(Float64(Float64(-1.0 - Float64(1.0 + Float64(x_m - x_m))) / Float64(1.0 - x_m)) / Float64(-1.0 - x_m))
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = ((-1.0 - (1.0 + (x_m - x_m))) / (1.0 - x_m)) / (-1.0 - x_m);
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[(N[(N[(-1.0 - N[(1.0 + N[(x$95$m - x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / 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{-1 - \left(1 + \left(x_m - x_m\right)\right)}{1 - x_m}}{-1 - x_m}
\end{array}
Derivation
  1. Initial program 70.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative70.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac70.9%

      \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
    4. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
    5. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    6. metadata-eval70.9%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    7. associate-/r*70.9%

      \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
    8. metadata-eval70.9%

      \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
    9. neg-mul-170.9%

      \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    10. sub0-neg70.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    11. associate-+l-70.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    12. neg-sub070.9%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    13. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
    14. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
    15. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
    16. associate-/r*70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
    17. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
    18. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
    19. distribute-neg-in70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    20. sub-neg70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
    21. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    22. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
  3. Simplified70.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub71.6%

      \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. *-rgt-identity71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
    3. metadata-eval71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
    4. div-inv71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
    5. associate-/r*71.6%

      \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
    6. *-un-lft-identity71.6%

      \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x} \]
    7. metadata-eval71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    8. div-inv71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    9. associate--l-75.4%

      \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
    10. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    11. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    12. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    13. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
    14. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
    15. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
  6. Applied egg-rr75.4%

    \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
  7. Step-by-step derivation
    1. +-commutative75.4%

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

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

    \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
  9. Final simplification99.9%

    \[\leadsto \frac{\frac{-1 - \left(1 + \left(x - x\right)\right)}{1 - x}}{-1 - x} \]
  10. Add Preprocessing

Alternative 2: 98.1% accurate, 1.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x_m \leq 0.76:\\ \;\;\;\;\frac{-2}{x_m + \left(-1 - x_m\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{1 - x_m} \cdot \frac{-1}{x_m}\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= x_m 0.76)
   (/ -2.0 (+ x_m (- -1.0 x_m)))
   (* (/ -2.0 (- 1.0 x_m)) (/ -1.0 x_m))))
x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (x_m <= 0.76) {
		tmp = -2.0 / (x_m + (-1.0 - x_m));
	} else {
		tmp = (-2.0 / (1.0 - 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 <= 0.76d0) then
        tmp = (-2.0d0) / (x_m + ((-1.0d0) - x_m))
    else
        tmp = ((-2.0d0) / (1.0d0 - 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 <= 0.76) {
		tmp = -2.0 / (x_m + (-1.0 - x_m));
	} else {
		tmp = (-2.0 / (1.0 - x_m)) * (-1.0 / x_m);
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if x_m <= 0.76:
		tmp = -2.0 / (x_m + (-1.0 - x_m))
	else:
		tmp = (-2.0 / (1.0 - x_m)) * (-1.0 / x_m)
	return tmp
x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (x_m <= 0.76)
		tmp = Float64(-2.0 / Float64(x_m + Float64(-1.0 - x_m)));
	else
		tmp = Float64(Float64(-2.0 / Float64(1.0 - 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 <= 0.76)
		tmp = -2.0 / (x_m + (-1.0 - x_m));
	else
		tmp = (-2.0 / (1.0 - 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, 0.76], N[(-2.0 / N[(x$95$m + N[(-1.0 - x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 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|

\\
\begin{array}{l}
\mathbf{if}\;x_m \leq 0.76:\\
\;\;\;\;\frac{-2}{x_m + \left(-1 - x_m\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{-2}{1 - x_m} \cdot \frac{-1}{x_m}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.76000000000000001

    1. Initial program 78.7%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg78.7%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative78.7%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac78.7%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval78.7%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*78.7%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval78.7%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-178.7%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg78.7%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-78.7%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub078.7%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in78.7%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified78.7%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg78.7%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac78.7%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval78.7%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr78.7%

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

      \[\leadsto \color{blue}{\frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    8. Step-by-step derivation
      1. *-commutative99.9%

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

        \[\leadsto \frac{-2}{\left(-1 - x\right) \cdot \color{blue}{\left(1 + \left(-x\right)\right)}} \]
      3. distribute-lft-in99.9%

        \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right) \cdot 1 + \left(-1 - x\right) \cdot \left(-x\right)}} \]
      4. *-commutative99.9%

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

        \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right)} + \left(-1 - x\right) \cdot \left(-x\right)} \]
    9. Applied egg-rr99.9%

      \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right) + \left(-1 - x\right) \cdot \left(-x\right)}} \]
    10. Taylor expanded in x around 0 59.9%

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

    if 0.76000000000000001 < x

    1. Initial program 49.1%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg49.1%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative49.1%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac49.1%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval49.1%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*49.1%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval49.1%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-149.1%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg49.1%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-49.1%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub049.1%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      20. sub-neg49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified49.1%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg49.1%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac49.1%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval49.1%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr49.1%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
    7. Simplified97.8%

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

        \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x}}{-1 - x}} \]
      2. div-inv99.6%

        \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{1}{-1 - x}} \]
    9. Applied egg-rr99.6%

      \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{1}{-1 - x}} \]
    10. Taylor expanded in x around inf 96.5%

      \[\leadsto \frac{-2}{1 - x} \cdot \color{blue}{\frac{-1}{x}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification69.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 0.76:\\ \;\;\;\;\frac{-2}{x + \left(-1 - x\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{1 - x} \cdot \frac{-1}{x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.8% accurate, 1.0× speedup?

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

\\
\frac{-2}{1 - x_m} \cdot \frac{1}{-1 - x_m}
\end{array}
Derivation
  1. Initial program 70.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative70.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac70.9%

      \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
    4. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
    5. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    6. metadata-eval70.9%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    7. associate-/r*70.9%

      \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
    8. metadata-eval70.9%

      \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
    9. neg-mul-170.9%

      \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    10. sub0-neg70.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    11. associate-+l-70.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    12. neg-sub070.9%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    13. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
    14. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
    15. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
    16. associate-/r*70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
    17. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
    18. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
    19. distribute-neg-in70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    20. sub-neg70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
    21. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    22. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
  3. Simplified70.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval70.9%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr70.9%

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

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

      \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x}}{-1 - x}} \]
    2. div-inv99.7%

      \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{1}{-1 - x}} \]
  9. Applied egg-rr99.7%

    \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{1}{-1 - x}} \]
  10. Final simplification99.7%

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

Alternative 4: 75.5% accurate, 1.2× speedup?

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

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

\mathbf{else}:\\
\;\;\;\;0\\


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

    1. Initial program 78.7%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg78.7%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative78.7%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac78.7%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval78.7%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*78.7%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval78.7%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-178.7%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg78.7%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-78.7%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub078.7%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in78.7%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified78.7%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg78.7%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac78.7%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval78.7%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr78.7%

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

      \[\leadsto \color{blue}{\frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    8. Step-by-step derivation
      1. *-commutative99.9%

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

        \[\leadsto \frac{-2}{\left(-1 - x\right) \cdot \color{blue}{\left(1 + \left(-x\right)\right)}} \]
      3. distribute-lft-in99.9%

        \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right) \cdot 1 + \left(-1 - x\right) \cdot \left(-x\right)}} \]
      4. *-commutative99.9%

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

        \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right)} + \left(-1 - x\right) \cdot \left(-x\right)} \]
    9. Applied egg-rr99.9%

      \[\leadsto \frac{-2}{\color{blue}{\left(-1 - x\right) + \left(-1 - x\right) \cdot \left(-x\right)}} \]
    10. Taylor expanded in x around 0 59.9%

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

    if 1 < x

    1. Initial program 49.1%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg49.1%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative49.1%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac49.1%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval49.1%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*49.1%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval49.1%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-149.1%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg49.1%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-49.1%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub049.1%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      20. sub-neg49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified49.1%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub50.6%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*50.6%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. *-un-lft-identity50.6%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x} \]
      7. metadata-eval50.6%

        \[\leadsto \frac{\frac{\left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. div-inv50.6%

        \[\leadsto \frac{\frac{\left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-56.9%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr56.9%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Step-by-step derivation
      1. +-commutative56.9%

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

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

      \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
    9. Applied egg-rr44.6%

      \[\leadsto \color{blue}{0} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification55.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 1:\\ \;\;\;\;\frac{-2}{x + \left(-1 - x\right)}\\ \mathbf{else}:\\ \;\;\;\;0\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 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 70.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative70.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac70.9%

      \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
    4. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
    5. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    6. metadata-eval70.9%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    7. associate-/r*70.9%

      \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
    8. metadata-eval70.9%

      \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
    9. neg-mul-170.9%

      \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    10. sub0-neg70.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    11. associate-+l-70.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    12. neg-sub070.9%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    13. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
    14. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
    15. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
    16. associate-/r*70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
    17. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
    18. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
    19. distribute-neg-in70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    20. sub-neg70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
    21. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    22. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
  3. Simplified70.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval70.9%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr70.9%

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

    \[\leadsto \color{blue}{\frac{-2}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
  8. Final simplification99.3%

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

Alternative 6: 75.5% accurate, 3.5× speedup?

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

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

\mathbf{else}:\\
\;\;\;\;0\\


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

    1. Initial program 78.7%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg78.7%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative78.7%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac78.7%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval78.7%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval78.7%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*78.7%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval78.7%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-178.7%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg78.7%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-78.7%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub078.7%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in78.7%

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

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac78.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-178.7%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified78.7%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 60.2%

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

    if 1 < x

    1. Initial program 49.1%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg49.1%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative49.1%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac49.1%

        \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
      4. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
      5. metadata-eval49.1%

        \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      6. metadata-eval49.1%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
      7. associate-/r*49.1%

        \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
      8. metadata-eval49.1%

        \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
      9. neg-mul-149.1%

        \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      10. sub0-neg49.1%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      11. associate-+l-49.1%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      12. neg-sub049.1%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      13. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
      14. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
      15. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
      16. associate-/r*49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
      17. metadata-eval49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
      18. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
      19. distribute-neg-in49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      20. sub-neg49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
      21. distribute-neg-frac49.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      22. neg-mul-149.1%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
    3. Simplified49.1%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub50.6%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv50.6%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*50.6%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. *-un-lft-identity50.6%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x} \]
      7. metadata-eval50.6%

        \[\leadsto \frac{\frac{\left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. div-inv50.6%

        \[\leadsto \frac{\frac{\left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-56.9%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity56.9%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr56.9%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Step-by-step derivation
      1. +-commutative56.9%

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

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

      \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
    9. Applied egg-rr44.6%

      \[\leadsto \color{blue}{0} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification56.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 1:\\ \;\;\;\;2\\ \mathbf{else}:\\ \;\;\;\;0\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 2.9% accurate, 21.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ -0.3333333333333333 \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 -0.3333333333333333)
x_m = fabs(x);
double code(double x_m) {
	return -0.3333333333333333;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = -0.3333333333333333d0
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return -0.3333333333333333;
}
x_m = math.fabs(x)
def code(x_m):
	return -0.3333333333333333
x_m = abs(x)
function code(x_m)
	return -0.3333333333333333
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = -0.3333333333333333;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := -0.3333333333333333
\begin{array}{l}
x_m = \left|x\right|

\\
-0.3333333333333333
\end{array}
Derivation
  1. Initial program 70.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative70.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac70.9%

      \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
    4. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
    5. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    6. metadata-eval70.9%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    7. associate-/r*70.9%

      \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
    8. metadata-eval70.9%

      \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
    9. neg-mul-170.9%

      \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    10. sub0-neg70.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    11. associate-+l-70.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    12. neg-sub070.9%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    13. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
    14. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
    15. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
    16. associate-/r*70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
    17. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
    18. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
    19. distribute-neg-in70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    20. sub-neg70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
    21. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    22. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
  3. Simplified70.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub71.6%

      \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. *-rgt-identity71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
    3. metadata-eval71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
    4. div-inv71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
    5. associate-/r*71.6%

      \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
    6. *-un-lft-identity71.6%

      \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x} \]
    7. metadata-eval71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    8. div-inv71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    9. associate--l-75.4%

      \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
    10. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    11. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    12. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    13. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
    14. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
    15. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
  6. Applied egg-rr75.4%

    \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
  7. Step-by-step derivation
    1. +-commutative75.4%

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

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

    \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
  9. Applied egg-rr3.2%

    \[\leadsto \color{blue}{-0.3333333333333333} \]
  10. Final simplification3.2%

    \[\leadsto -0.3333333333333333 \]
  11. Add Preprocessing

Alternative 8: 27.5% accurate, 21.0× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ 0 \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 0.0)
x_m = fabs(x);
double code(double x_m) {
	return 0.0;
}
x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = 0.0d0
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return 0.0;
}
x_m = math.fabs(x)
def code(x_m):
	return 0.0
x_m = abs(x)
function code(x_m)
	return 0.0
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = 0.0;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := 0.0
\begin{array}{l}
x_m = \left|x\right|

\\
0
\end{array}
Derivation
  1. Initial program 70.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg70.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative70.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac70.9%

      \[\leadsto \color{blue}{\frac{-1}{x - 1}} + \frac{1}{x + 1} \]
    4. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{-1}}{x - 1} + \frac{1}{x + 1} \]
    5. metadata-eval70.9%

      \[\leadsto \frac{\color{blue}{\frac{1}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    6. metadata-eval70.9%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1}}}{x - 1} + \frac{1}{x + 1} \]
    7. associate-/r*70.9%

      \[\leadsto \color{blue}{\frac{1}{\left(-1\right) \cdot \left(x - 1\right)}} + \frac{1}{x + 1} \]
    8. metadata-eval70.9%

      \[\leadsto \frac{1}{\color{blue}{-1} \cdot \left(x - 1\right)} + \frac{1}{x + 1} \]
    9. neg-mul-170.9%

      \[\leadsto \frac{1}{\color{blue}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    10. sub0-neg70.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    11. associate-+l-70.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    12. neg-sub070.9%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    13. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\color{blue}{\frac{-1}{-1}}}{x + 1} \]
    14. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{\color{blue}{-1}}{-1}}{x + 1} \]
    15. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{\frac{-1}{\color{blue}{-1}}}{x + 1} \]
    16. associate-/r*70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\frac{-1}{\left(-1\right) \cdot \left(x + 1\right)}} \]
    17. metadata-eval70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-1} \cdot \left(x + 1\right)} \]
    18. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{-\left(x + 1\right)}} \]
    19. distribute-neg-in70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    20. sub-neg70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{-1}{\color{blue}{\left(-x\right) - 1}} \]
    21. distribute-neg-frac70.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    22. neg-mul-170.9%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{-1 \cdot \frac{1}{\left(-x\right) - 1}} \]
  3. Simplified70.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub71.6%

      \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. *-rgt-identity71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
    3. metadata-eval71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
    4. div-inv71.6%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
    5. associate-/r*71.6%

      \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
    6. *-un-lft-identity71.6%

      \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x} \]
    7. metadata-eval71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    8. div-inv71.6%

      \[\leadsto \frac{\frac{\left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    9. associate--l-75.4%

      \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
    10. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    11. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    12. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    13. div-inv75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
    14. metadata-eval75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
    15. *-rgt-identity75.4%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
  6. Applied egg-rr75.4%

    \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
  7. Step-by-step derivation
    1. +-commutative75.4%

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

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

    \[\leadsto \frac{\frac{-1 - \color{blue}{\left(1 - \left(x - x\right)\right)}}{1 - x}}{-1 - x} \]
  9. Applied egg-rr25.8%

    \[\leadsto \color{blue}{0} \]
  10. Final simplification25.8%

    \[\leadsto 0 \]
  11. Add Preprocessing

Reproduce

?
herbie shell --seed 2024011 
(FPCore (x)
  :name "Asymptote A"
  :precision binary64
  (- (/ 1.0 (+ x 1.0)) (/ 1.0 (- x 1.0))))