Asymptote A

Percentage Accurate: 78.1% → 99.9%
Time: 9.3s
Alternatives: 6
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 6 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: 78.1% 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?

\[\begin{array}{l} \\ \frac{\frac{2}{x + -1}}{-1 - x} \end{array} \]
(FPCore (x) :precision binary64 (/ (/ 2.0 (+ x -1.0)) (- -1.0 x)))
double code(double x) {
	return (2.0 / (x + -1.0)) / (-1.0 - x);
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (2.0d0 / (x + (-1.0d0))) / ((-1.0d0) - x)
end function
public static double code(double x) {
	return (2.0 / (x + -1.0)) / (-1.0 - x);
}
def code(x):
	return (2.0 / (x + -1.0)) / (-1.0 - x)
function code(x)
	return Float64(Float64(2.0 / Float64(x + -1.0)) / Float64(-1.0 - x))
end
function tmp = code(x)
	tmp = (2.0 / (x + -1.0)) / (-1.0 - x);
end
code[x_] := N[(N[(2.0 / N[(x + -1.0), $MachinePrecision]), $MachinePrecision] / N[(-1.0 - x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{2}{x + -1}}{-1 - x}
\end{array}
Derivation
  1. Initial program 77.7%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.7%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.7%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.7%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.7%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg77.7%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.7%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub78.4%

      \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
    2. *-rgt-identity78.4%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
    3. metadata-eval78.4%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
    4. div-inv78.4%

      \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
    5. associate-/r*78.4%

      \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
    6. metadata-eval78.4%

      \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    7. div-inv78.4%

      \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
    8. *-un-lft-identity78.4%

      \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
    9. associate--l-81.3%

      \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
    10. div-inv81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    11. metadata-eval81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    12. *-rgt-identity81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
    13. div-inv81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
    14. metadata-eval81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
    15. *-rgt-identity81.3%

      \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
  6. Applied egg-rr81.3%

    \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
  7. Step-by-step derivation
    1. div-sub81.3%

      \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} - \frac{x + \left(1 - x\right)}{1 - x}}}{-1 - x} \]
    2. sub-neg81.3%

      \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}}{-1 - x} \]
    3. frac-2neg81.3%

      \[\leadsto \frac{\color{blue}{\frac{--1}{-\left(1 - x\right)}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    4. metadata-eval81.3%

      \[\leadsto \frac{\frac{\color{blue}{1}}{-\left(1 - x\right)} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    5. flip--81.3%

      \[\leadsto \frac{\frac{1}{-\color{blue}{\frac{1 \cdot 1 - x \cdot x}{1 + x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    6. metadata-eval81.3%

      \[\leadsto \frac{\frac{1}{-\frac{\color{blue}{1} - x \cdot x}{1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    7. metadata-eval81.3%

      \[\leadsto \frac{\frac{1}{-\frac{\color{blue}{-1 \cdot -1} - x \cdot x}{1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    8. +-commutative81.3%

      \[\leadsto \frac{\frac{1}{-\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{x + 1}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    9. distribute-neg-frac281.3%

      \[\leadsto \frac{\frac{1}{\color{blue}{\frac{-1 \cdot -1 - x \cdot x}{-\left(x + 1\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    10. mul-1-neg81.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 \cdot \left(x + 1\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    11. +-commutative81.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{-1 \cdot \color{blue}{\left(1 + x\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    12. distribute-lft-in81.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 \cdot 1 + -1 \cdot x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    13. metadata-eval81.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1} + -1 \cdot x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    14. neg-mul-181.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{-1 + \color{blue}{\left(-x\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    15. sub-neg81.3%

      \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 - x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    16. flip-+81.3%

      \[\leadsto \frac{\frac{1}{\color{blue}{-1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    17. +-commutative81.3%

      \[\leadsto \frac{\frac{1}{\color{blue}{x + -1}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
    18. associate-+r-81.3%

      \[\leadsto \frac{\frac{1}{x + -1} + \left(-\frac{\color{blue}{\left(x + 1\right) - x}}{1 - x}\right)}{-1 - x} \]
    19. +-commutative81.3%

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

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

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

      \[\leadsto \frac{\frac{1}{x + -1} + \color{blue}{\frac{1 + \left(x - x\right)}{-\left(1 - x\right)}}}{-1 - x} \]
    2. +-inverses99.9%

      \[\leadsto \frac{\frac{1}{x + -1} + \frac{1 + \color{blue}{0}}{-\left(1 - x\right)}}{-1 - x} \]
    3. metadata-eval99.9%

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

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

      \[\leadsto \frac{\frac{1}{x + -1} + \frac{1}{\color{blue}{\left(0 - 1\right) + x}}}{-1 - x} \]
    6. metadata-eval99.9%

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

      \[\leadsto \frac{\frac{1}{x + -1} + \frac{1}{\color{blue}{x + -1}}}{-1 - x} \]
    8. count-299.9%

      \[\leadsto \frac{\color{blue}{2 \cdot \frac{1}{x + -1}}}{-1 - x} \]
    9. associate-*r/99.9%

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

      \[\leadsto \frac{\frac{\color{blue}{2}}{x + -1}}{-1 - x} \]
  10. Simplified99.9%

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

Alternative 2: 74.3% accurate, 1.0× speedup?

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

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

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


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

    1. Initial program 86.6%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg86.6%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative86.6%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac286.6%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub086.6%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-86.6%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub086.6%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac286.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg86.6%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative86.6%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg86.6%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified86.6%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 69.0%

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

    if 1 < x

    1. Initial program 51.6%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg51.6%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative51.6%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac251.6%

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

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-51.6%

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

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac251.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg51.6%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative51.6%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg51.6%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified51.6%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-sub52.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(1 - x\right) \cdot \left(-1 - x\right)}} \]
      2. *-rgt-identity52.9%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\left(\left(1 - x\right) \cdot 1\right)} \cdot \left(-1 - x\right)} \]
      3. metadata-eval52.9%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\left(\left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}\right) \cdot \left(-1 - x\right)} \]
      4. div-inv52.9%

        \[\leadsto \frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\color{blue}{\frac{1 - x}{1}} \cdot \left(-1 - x\right)} \]
      5. associate-/r*52.9%

        \[\leadsto \color{blue}{\frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot 1}{\frac{1 - x}{1}}}{-1 - x}} \]
      6. metadata-eval52.9%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \left(1 - x\right) \cdot \color{blue}{\frac{1}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      7. div-inv52.9%

        \[\leadsto \frac{\frac{1 \cdot \left(-1 - x\right) - \color{blue}{\frac{1 - x}{1}}}{\frac{1 - x}{1}}}{-1 - x} \]
      8. *-un-lft-identity52.9%

        \[\leadsto \frac{\frac{\color{blue}{\left(-1 - x\right)} - \frac{1 - x}{1}}{\frac{1 - x}{1}}}{-1 - x} \]
      9. associate--l-59.4%

        \[\leadsto \frac{\frac{\color{blue}{-1 - \left(x + \frac{1 - x}{1}\right)}}{\frac{1 - x}{1}}}{-1 - x} \]
      10. div-inv59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      11. metadata-eval59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right) \cdot \color{blue}{1}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      12. *-rgt-identity59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \color{blue}{\left(1 - x\right)}\right)}{\frac{1 - x}{1}}}{-1 - x} \]
      13. div-inv59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{\left(1 - x\right) \cdot \frac{1}{1}}}}{-1 - x} \]
      14. metadata-eval59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\left(1 - x\right) \cdot \color{blue}{1}}}{-1 - x} \]
      15. *-rgt-identity59.4%

        \[\leadsto \frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{\color{blue}{1 - x}}}{-1 - x} \]
    6. Applied egg-rr59.4%

      \[\leadsto \color{blue}{\frac{\frac{-1 - \left(x + \left(1 - x\right)\right)}{1 - x}}{-1 - x}} \]
    7. Step-by-step derivation
      1. div-sub59.4%

        \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} - \frac{x + \left(1 - x\right)}{1 - x}}}{-1 - x} \]
      2. sub-neg59.4%

        \[\leadsto \frac{\color{blue}{\frac{-1}{1 - x} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}}{-1 - x} \]
      3. frac-2neg59.4%

        \[\leadsto \frac{\color{blue}{\frac{--1}{-\left(1 - x\right)}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      4. metadata-eval59.4%

        \[\leadsto \frac{\frac{\color{blue}{1}}{-\left(1 - x\right)} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      5. flip--59.4%

        \[\leadsto \frac{\frac{1}{-\color{blue}{\frac{1 \cdot 1 - x \cdot x}{1 + x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      6. metadata-eval59.4%

        \[\leadsto \frac{\frac{1}{-\frac{\color{blue}{1} - x \cdot x}{1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      7. metadata-eval59.4%

        \[\leadsto \frac{\frac{1}{-\frac{\color{blue}{-1 \cdot -1} - x \cdot x}{1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      8. +-commutative59.4%

        \[\leadsto \frac{\frac{1}{-\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{x + 1}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      9. distribute-neg-frac259.4%

        \[\leadsto \frac{\frac{1}{\color{blue}{\frac{-1 \cdot -1 - x \cdot x}{-\left(x + 1\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      10. mul-1-neg59.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 \cdot \left(x + 1\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      11. +-commutative59.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{-1 \cdot \color{blue}{\left(1 + x\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      12. distribute-lft-in59.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 \cdot 1 + -1 \cdot x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      13. metadata-eval59.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1} + -1 \cdot x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      14. neg-mul-159.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{-1 + \color{blue}{\left(-x\right)}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      15. sub-neg59.4%

        \[\leadsto \frac{\frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 - x}}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      16. flip-+59.4%

        \[\leadsto \frac{\frac{1}{\color{blue}{-1 + x}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      17. +-commutative59.4%

        \[\leadsto \frac{\frac{1}{\color{blue}{x + -1}} + \left(-\frac{x + \left(1 - x\right)}{1 - x}\right)}{-1 - x} \]
      18. associate-+r-59.4%

        \[\leadsto \frac{\frac{1}{x + -1} + \left(-\frac{\color{blue}{\left(x + 1\right) - x}}{1 - x}\right)}{-1 - x} \]
      19. +-commutative59.4%

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

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

      \[\leadsto \frac{\color{blue}{\frac{1}{x + -1} + \left(-\frac{1 + \left(x - x\right)}{1 - x}\right)}}{-1 - x} \]
    9. Step-by-step derivation
      1. distribute-neg-frac299.8%

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

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

        \[\leadsto \frac{\frac{1}{x + -1} + \frac{\color{blue}{1}}{-\left(1 - x\right)}}{-1 - x} \]
      4. neg-sub099.8%

        \[\leadsto \frac{\frac{1}{x + -1} + \frac{1}{\color{blue}{0 - \left(1 - x\right)}}}{-1 - x} \]
      5. associate--r-99.8%

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

        \[\leadsto \frac{\frac{1}{x + -1} + \frac{1}{\color{blue}{-1} + x}}{-1 - x} \]
      7. +-commutative99.8%

        \[\leadsto \frac{\frac{1}{x + -1} + \frac{1}{\color{blue}{x + -1}}}{-1 - x} \]
      8. count-299.8%

        \[\leadsto \frac{\color{blue}{2 \cdot \frac{1}{x + -1}}}{-1 - x} \]
      9. associate-*r/99.8%

        \[\leadsto \frac{\color{blue}{\frac{2 \cdot 1}{x + -1}}}{-1 - x} \]
      10. metadata-eval99.8%

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

      \[\leadsto \frac{\color{blue}{\frac{2}{x + -1}}}{-1 - x} \]
    11. Taylor expanded in x around inf 98.6%

      \[\leadsto \frac{\frac{2}{x + -1}}{\color{blue}{-1 \cdot x}} \]
    12. Step-by-step derivation
      1. neg-mul-198.6%

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

      \[\leadsto \frac{\frac{2}{x + -1}}{\color{blue}{-x}} \]
    14. Taylor expanded in x around inf 99.2%

      \[\leadsto \frac{\frac{2}{\color{blue}{x}}}{-x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification76.7%

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

Alternative 3: 99.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{-2}{\left(x + -1\right) \cdot \left(x + 1\right)} \end{array} \]
(FPCore (x) :precision binary64 (/ -2.0 (* (+ x -1.0) (+ x 1.0))))
double code(double x) {
	return -2.0 / ((x + -1.0) * (x + 1.0));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (-2.0d0) / ((x + (-1.0d0)) * (x + 1.0d0))
end function
public static double code(double x) {
	return -2.0 / ((x + -1.0) * (x + 1.0));
}
def code(x):
	return -2.0 / ((x + -1.0) * (x + 1.0))
function code(x)
	return Float64(-2.0 / Float64(Float64(x + -1.0) * Float64(x + 1.0)))
end
function tmp = code(x)
	tmp = -2.0 / ((x + -1.0) * (x + 1.0));
end
code[x_] := N[(-2.0 / N[(N[(x + -1.0), $MachinePrecision] * N[(x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2}{\left(x + -1\right) \cdot \left(x + 1\right)}
\end{array}
Derivation
  1. Initial program 77.7%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.7%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.7%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.7%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.7%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg77.7%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.7%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac77.7%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval77.7%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr77.7%

    \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
  7. Simplified98.9%

    \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
  8. Final simplification98.9%

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

Alternative 4: 52.2% accurate, 1.4× speedup?

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

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

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


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

    1. Initial program 86.6%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg86.6%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative86.6%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac286.6%

        \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
      4. neg-sub086.6%

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-86.6%

        \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
      6. neg-sub086.6%

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg86.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac286.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg86.6%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative86.6%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg86.6%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval86.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified86.6%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 69.0%

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

    if 1 < x

    1. Initial program 51.6%

      \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg51.6%

        \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
      2. +-commutative51.6%

        \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
      3. distribute-neg-frac251.6%

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

        \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
      5. associate-+l-51.6%

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

        \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
      7. remove-double-neg51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
      8. distribute-neg-in51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
      9. sub-neg51.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
      10. distribute-neg-frac251.6%

        \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
      11. sub-neg51.6%

        \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
      12. +-commutative51.6%

        \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
      13. unsub-neg51.6%

        \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
      14. sub-neg51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
      15. +-commutative51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
      16. unsub-neg51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
      17. metadata-eval51.6%

        \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
    3. Simplified51.6%

      \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. sub-neg51.6%

        \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
      2. distribute-neg-frac51.6%

        \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
      3. metadata-eval51.6%

        \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
    6. Applied egg-rr51.6%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \frac{-1}{-1 - x}} \]
    7. Simplified97.9%

      \[\leadsto \color{blue}{\frac{-2}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    8. Taylor expanded in x around inf 96.8%

      \[\leadsto \frac{-2}{\left(x + 1\right) \cdot \color{blue}{x}} \]
    9. Taylor expanded in x around 0 6.7%

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

Alternative 5: 51.2% accurate, 11.0× speedup?

\[\begin{array}{l} \\ 2 \end{array} \]
(FPCore (x) :precision binary64 2.0)
double code(double x) {
	return 2.0;
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 2.0d0
end function
public static double code(double x) {
	return 2.0;
}
def code(x):
	return 2.0
function code(x)
	return 2.0
end
function tmp = code(x)
	tmp = 2.0;
end
code[x_] := 2.0
\begin{array}{l}

\\
2
\end{array}
Derivation
  1. Initial program 77.7%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.7%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.7%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.7%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.7%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg77.7%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.7%

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

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

Alternative 6: 10.8% accurate, 11.0× speedup?

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

\\
1
\end{array}
Derivation
  1. Initial program 77.7%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.7%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.7%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.7%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.7%

      \[\leadsto \frac{1}{\color{blue}{\left(-x\right)} + 1} + \frac{1}{x + 1} \]
    7. remove-double-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) + \left(-1\right)\right)}} \]
    9. sub-neg77.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.7%

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)} \]
    11. sub-neg77.7%

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.7%

      \[\leadsto \frac{1}{\color{blue}{1 + \left(-x\right)}} - \frac{1}{\left(-x\right) - 1} \]
    13. unsub-neg77.7%

      \[\leadsto \frac{1}{\color{blue}{1 - x}} - \frac{1}{\left(-x\right) - 1} \]
    14. sub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) + \left(-x\right)}} \]
    16. unsub-neg77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.7%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.7%

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

    \[\leadsto \frac{1}{1 - x} - \color{blue}{-1} \]
  6. Taylor expanded in x around inf 10.9%

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

Reproduce

?
herbie shell --seed 2024110 
(FPCore (x)
  :name "Asymptote A"
  :precision binary64
  (- (/ 1.0 (+ x 1.0)) (/ 1.0 (- x 1.0))))