Asymptote A

Percentage Accurate: 78.0% → 99.9%
Time: 5.9s
Alternatives: 5
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 5 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: 78.0% 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?

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

\\
\frac{\frac{-2}{1 - x}}{-1 - x}
\end{array}
Derivation
  1. Initial program 77.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.9%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.9%

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

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.9%

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

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.9%

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac77.9%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr77.9%

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

    \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x}}{-1 - x}} \]
  8. Final simplification99.9%

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

Alternative 2: 99.3% accurate, 1.2× speedup?

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

\\
\frac{2}{\left(-1 - x\right) \cdot \left(x + -1\right)}
\end{array}
Derivation
  1. Initial program 77.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.9%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.9%

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

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.9%

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

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.9%

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac77.9%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr77.9%

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

    \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x}}{-1 - x}} \]
  8. Step-by-step derivation
    1. flip--99.6%

      \[\leadsto \frac{\frac{-2}{1 - x}}{\color{blue}{\frac{-1 \cdot -1 - x \cdot x}{-1 + x}}} \]
    2. associate-/r/93.2%

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

      \[\leadsto \frac{\frac{-2}{1 - x}}{\color{blue}{1} - x \cdot x} \cdot \left(-1 + x\right) \]
    4. pow293.2%

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

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

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

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

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \left(\color{blue}{\left(0 - 1\right)} + x\right) \]
    3. associate--r-93.2%

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \color{blue}{\left(0 - \left(1 - x\right)\right)} \]
    4. neg-sub093.2%

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \color{blue}{\left(-\left(1 - x\right)\right)} \]
    5. associate-*l/99.6%

      \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x} \cdot \left(-\left(1 - x\right)\right)}{1 - {x}^{2}}} \]
    6. associate-/l*99.5%

      \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}}} \]
    7. metadata-eval99.5%

      \[\leadsto \frac{\color{blue}{-2}}{1 - x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    8. distribute-neg-frac99.5%

      \[\leadsto \color{blue}{\left(-\frac{2}{1 - x}\right)} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    9. distribute-neg-frac299.5%

      \[\leadsto \color{blue}{\frac{2}{-\left(1 - x\right)}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    10. neg-sub099.5%

      \[\leadsto \frac{2}{\color{blue}{0 - \left(1 - x\right)}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    11. associate--r-99.5%

      \[\leadsto \frac{2}{\color{blue}{\left(0 - 1\right) + x}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    12. metadata-eval99.5%

      \[\leadsto \frac{2}{\color{blue}{-1} + x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    13. +-commutative99.5%

      \[\leadsto \frac{2}{\color{blue}{x + -1}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    14. neg-sub099.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{0 - \left(1 - x\right)}}{1 - {x}^{2}} \]
    15. associate--r-99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{\left(0 - 1\right) + x}}{1 - {x}^{2}} \]
    16. metadata-eval99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{-1} + x}{1 - {x}^{2}} \]
    17. +-commutative99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{x + -1}}{1 - {x}^{2}} \]
  11. Simplified99.5%

    \[\leadsto \color{blue}{\frac{2}{x + -1} \cdot \frac{x + -1}{1 - {x}^{2}}} \]
  12. Step-by-step derivation
    1. *-commutative99.5%

      \[\leadsto \color{blue}{\frac{x + -1}{1 - {x}^{2}} \cdot \frac{2}{x + -1}} \]
    2. clear-num99.5%

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

      \[\leadsto \frac{1}{\frac{\color{blue}{-1 \cdot -1} - {x}^{2}}{x + -1}} \cdot \frac{2}{x + -1} \]
    4. unpow299.5%

      \[\leadsto \frac{1}{\frac{-1 \cdot -1 - \color{blue}{x \cdot x}}{x + -1}} \cdot \frac{2}{x + -1} \]
    5. +-commutative99.5%

      \[\leadsto \frac{1}{\frac{-1 \cdot -1 - x \cdot x}{\color{blue}{-1 + x}}} \cdot \frac{2}{x + -1} \]
    6. flip--99.8%

      \[\leadsto \frac{1}{\color{blue}{-1 - x}} \cdot \frac{2}{x + -1} \]
    7. frac-times99.6%

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

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

      \[\leadsto \frac{2}{\left(-1 - x\right) \cdot \color{blue}{\left(-1 + x\right)}} \]
  13. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\frac{2}{\left(-1 - x\right) \cdot \left(-1 + x\right)}} \]
  14. Step-by-step derivation
    1. +-commutative99.6%

      \[\leadsto \frac{2}{\left(-1 - x\right) \cdot \color{blue}{\left(x + -1\right)}} \]
  15. Simplified99.6%

    \[\leadsto \color{blue}{\frac{2}{\left(-1 - x\right) \cdot \left(x + -1\right)}} \]
  16. Final simplification99.6%

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

Alternative 3: 52.2% accurate, 1.8× speedup?

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

\\
\frac{-2}{x + -1}
\end{array}
Derivation
  1. Initial program 77.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.9%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.9%

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

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.9%

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

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.9%

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{1 - x} + \left(-\frac{1}{-1 - x}\right)} \]
    2. distribute-neg-frac77.9%

      \[\leadsto \frac{1}{1 - x} + \color{blue}{\frac{-1}{-1 - x}} \]
    3. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} + \frac{\color{blue}{-1}}{-1 - x} \]
  6. Applied egg-rr77.9%

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

    \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x}}{-1 - x}} \]
  8. Step-by-step derivation
    1. flip--99.6%

      \[\leadsto \frac{\frac{-2}{1 - x}}{\color{blue}{\frac{-1 \cdot -1 - x \cdot x}{-1 + x}}} \]
    2. associate-/r/93.2%

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

      \[\leadsto \frac{\frac{-2}{1 - x}}{\color{blue}{1} - x \cdot x} \cdot \left(-1 + x\right) \]
    4. pow293.2%

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

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

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

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

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \left(\color{blue}{\left(0 - 1\right)} + x\right) \]
    3. associate--r-93.2%

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \color{blue}{\left(0 - \left(1 - x\right)\right)} \]
    4. neg-sub093.2%

      \[\leadsto \frac{\frac{-2}{1 - x}}{1 - {x}^{2}} \cdot \color{blue}{\left(-\left(1 - x\right)\right)} \]
    5. associate-*l/99.6%

      \[\leadsto \color{blue}{\frac{\frac{-2}{1 - x} \cdot \left(-\left(1 - x\right)\right)}{1 - {x}^{2}}} \]
    6. associate-/l*99.5%

      \[\leadsto \color{blue}{\frac{-2}{1 - x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}}} \]
    7. metadata-eval99.5%

      \[\leadsto \frac{\color{blue}{-2}}{1 - x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    8. distribute-neg-frac99.5%

      \[\leadsto \color{blue}{\left(-\frac{2}{1 - x}\right)} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    9. distribute-neg-frac299.5%

      \[\leadsto \color{blue}{\frac{2}{-\left(1 - x\right)}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    10. neg-sub099.5%

      \[\leadsto \frac{2}{\color{blue}{0 - \left(1 - x\right)}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    11. associate--r-99.5%

      \[\leadsto \frac{2}{\color{blue}{\left(0 - 1\right) + x}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    12. metadata-eval99.5%

      \[\leadsto \frac{2}{\color{blue}{-1} + x} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    13. +-commutative99.5%

      \[\leadsto \frac{2}{\color{blue}{x + -1}} \cdot \frac{-\left(1 - x\right)}{1 - {x}^{2}} \]
    14. neg-sub099.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{0 - \left(1 - x\right)}}{1 - {x}^{2}} \]
    15. associate--r-99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{\left(0 - 1\right) + x}}{1 - {x}^{2}} \]
    16. metadata-eval99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{-1} + x}{1 - {x}^{2}} \]
    17. +-commutative99.5%

      \[\leadsto \frac{2}{x + -1} \cdot \frac{\color{blue}{x + -1}}{1 - {x}^{2}} \]
  11. Simplified99.5%

    \[\leadsto \color{blue}{\frac{2}{x + -1} \cdot \frac{x + -1}{1 - {x}^{2}}} \]
  12. Taylor expanded in x around 0 51.9%

    \[\leadsto \frac{2}{x + -1} \cdot \color{blue}{-1} \]
  13. Final simplification51.9%

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

Alternative 4: 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 77.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.9%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.9%

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

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.9%

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

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.9%

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 50.3%

    \[\leadsto \frac{1}{1 - x} - \color{blue}{-1} \]
  6. Taylor expanded in x around inf 10.7%

    \[\leadsto \color{blue}{1} \]
  7. Final simplification10.7%

    \[\leadsto 1 \]
  8. 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 77.9%

    \[\frac{1}{x + 1} - \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg77.9%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\frac{1}{x - 1}\right)} \]
    2. +-commutative77.9%

      \[\leadsto \color{blue}{\left(-\frac{1}{x - 1}\right) + \frac{1}{x + 1}} \]
    3. distribute-neg-frac277.9%

      \[\leadsto \color{blue}{\frac{1}{-\left(x - 1\right)}} + \frac{1}{x + 1} \]
    4. neg-sub077.9%

      \[\leadsto \frac{1}{\color{blue}{0 - \left(x - 1\right)}} + \frac{1}{x + 1} \]
    5. associate-+l-77.9%

      \[\leadsto \frac{1}{\color{blue}{\left(0 - x\right) + 1}} + \frac{1}{x + 1} \]
    6. neg-sub077.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{\color{blue}{-\left(-\left(x + 1\right)\right)}} \]
    8. distribute-neg-in77.9%

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

      \[\leadsto \frac{1}{\left(-x\right) + 1} + \frac{1}{-\color{blue}{\left(\left(-x\right) - 1\right)}} \]
    10. distribute-neg-frac277.9%

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

      \[\leadsto \color{blue}{\frac{1}{\left(-x\right) + 1} - \frac{1}{\left(-x\right) - 1}} \]
    12. +-commutative77.9%

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

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-x\right) + \left(-1\right)}} \]
    15. +-commutative77.9%

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

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{\left(-1\right) - x}} \]
    17. metadata-eval77.9%

      \[\leadsto \frac{1}{1 - x} - \frac{1}{\color{blue}{-1} - x} \]
  3. Simplified77.9%

    \[\leadsto \color{blue}{\frac{1}{1 - x} - \frac{1}{-1 - x}} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 51.0%

    \[\leadsto \color{blue}{2} \]
  6. Final simplification51.0%

    \[\leadsto 2 \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024041 
(FPCore (x)
  :name "Asymptote A"
  :precision binary64
  (- (/ 1.0 (+ x 1.0)) (/ 1.0 (- x 1.0))))