3frac (problem 3.3.3)

Percentage Accurate: 69.8% → 99.8%
Time: 9.0s
Alternatives: 6
Speedup: 1.4×

Specification

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

\\
\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \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: 69.8% accurate, 1.0× speedup?

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

\\
\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}
\end{array}

Alternative 1: 99.8% accurate, 1.4× speedup?

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

\\
\frac{\frac{2}{x}}{\left(-1 - x\right) \cdot \left(1 - x\right)}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-2neg68.3%

      \[\leadsto \frac{1}{x + -1} + \left(\color{blue}{\frac{--2}{-x}} - \frac{1}{-1 - x}\right) \]
    2. frac-2neg68.3%

      \[\leadsto \frac{1}{x + -1} + \left(\frac{--2}{-x} - \color{blue}{\frac{-1}{-\left(-1 - x\right)}}\right) \]
    3. metadata-eval68.3%

      \[\leadsto \frac{1}{x + -1} + \left(\frac{--2}{-x} - \frac{\color{blue}{-1}}{-\left(-1 - x\right)}\right) \]
    4. frac-sub19.7%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\left(--2\right) \cdot \left(-\left(-1 - x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)}} \]
    5. metadata-eval19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{2} \cdot \left(-\left(-1 - x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    6. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(-\color{blue}{\left(-1 + \left(-x\right)\right)}\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    7. distribute-neg-in19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \color{blue}{\left(\left(--1\right) + \left(-\left(-x\right)\right)\right)} - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    8. metadata-eval19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(\color{blue}{1} + \left(-\left(-x\right)\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    9. neg-mul-119.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 + \left(-\color{blue}{-1 \cdot x}\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    10. *-commutative19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 + \left(-\color{blue}{x \cdot -1}\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    11. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \color{blue}{\left(1 - x \cdot -1\right)} - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    12. *-commutative19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \color{blue}{-1 \cdot x}\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    13. neg-mul-119.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \color{blue}{\left(-x\right)}\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\left(-1 - x\right)\right)} \]
    14. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(-\color{blue}{\left(-1 + \left(-x\right)\right)}\right)} \]
    15. distribute-neg-in19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \color{blue}{\left(\left(--1\right) + \left(-\left(-x\right)\right)\right)}} \]
    16. metadata-eval19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(\color{blue}{1} + \left(-\left(-x\right)\right)\right)} \]
    17. neg-mul-119.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 + \left(-\color{blue}{-1 \cdot x}\right)\right)} \]
    18. *-commutative19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 + \left(-\color{blue}{x \cdot -1}\right)\right)} \]
    19. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \color{blue}{\left(1 - x \cdot -1\right)}} \]
    20. *-commutative19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \color{blue}{-1 \cdot x}\right)} \]
  6. Applied egg-rr19.7%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{2 \cdot \left(1 - \left(-x\right)\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)}} \]
  7. Step-by-step derivation
    1. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \color{blue}{\left(1 + \left(-\left(-x\right)\right)\right)} - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    2. remove-double-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{2 \cdot \left(1 + \color{blue}{x}\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    3. distribute-lft-in19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{\left(2 \cdot 1 + 2 \cdot x\right)} - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    4. metadata-eval19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(\color{blue}{2} + 2 \cdot x\right) - \left(-x\right) \cdot -1}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    5. *-commutative19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - \color{blue}{-1 \cdot \left(-x\right)}}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    6. neg-mul-119.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - \color{blue}{\left(-\left(-x\right)\right)}}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    7. remove-double-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - \color{blue}{x}}{\left(-x\right) \cdot \left(1 - \left(-x\right)\right)} \]
    8. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\left(-x\right) \cdot \color{blue}{\left(1 + \left(-\left(-x\right)\right)\right)}} \]
    9. remove-double-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\left(-x\right) \cdot \left(1 + \color{blue}{x}\right)} \]
    10. distribute-lft-in19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\color{blue}{\left(-x\right) \cdot 1 + \left(-x\right) \cdot x}} \]
    11. *-rgt-identity19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\color{blue}{\left(-x\right)} + \left(-x\right) \cdot x} \]
    12. neg-mul-119.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\color{blue}{-1 \cdot x} + \left(-x\right) \cdot x} \]
    13. distribute-rgt-in19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{\color{blue}{x \cdot \left(-1 + \left(-x\right)\right)}} \]
    14. sub-neg19.7%

      \[\leadsto \frac{1}{x + -1} + \frac{\left(2 + 2 \cdot x\right) - x}{x \cdot \color{blue}{\left(-1 - x\right)}} \]
  8. Simplified19.7%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\left(2 + 2 \cdot x\right) - x}{x \cdot \left(-1 - x\right)}} \]
  9. Taylor expanded in x around 0 19.7%

    \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{2 + x}}{x \cdot \left(-1 - x\right)} \]
  10. Step-by-step derivation
    1. +-commutative19.7%

      \[\leadsto \color{blue}{\frac{2 + x}{x \cdot \left(-1 - x\right)} + \frac{1}{x + -1}} \]
    2. associate-/r*68.3%

      \[\leadsto \color{blue}{\frac{\frac{2 + x}{x}}{-1 - x}} + \frac{1}{x + -1} \]
    3. frac-2neg68.3%

      \[\leadsto \frac{\frac{2 + x}{x}}{-1 - x} + \color{blue}{\frac{-1}{-\left(x + -1\right)}} \]
    4. metadata-eval68.3%

      \[\leadsto \frac{\frac{2 + x}{x}}{-1 - x} + \frac{\color{blue}{-1}}{-\left(x + -1\right)} \]
    5. frac-add68.3%

      \[\leadsto \color{blue}{\frac{\frac{2 + x}{x} \cdot \left(-\left(x + -1\right)\right) + \left(-1 - x\right) \cdot -1}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)}} \]
  11. Applied egg-rr68.3%

    \[\leadsto \color{blue}{\frac{\frac{2 + x}{x} \cdot \left(-\left(x + -1\right)\right) + \left(-1 - x\right) \cdot -1}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)}} \]
  12. Step-by-step derivation
    1. *-commutative68.3%

      \[\leadsto \frac{\color{blue}{\left(-\left(x + -1\right)\right) \cdot \frac{2 + x}{x}} + \left(-1 - x\right) \cdot -1}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    2. *-commutative68.3%

      \[\leadsto \frac{\left(-\left(x + -1\right)\right) \cdot \frac{2 + x}{x} + \color{blue}{-1 \cdot \left(-1 - x\right)}}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    3. mul-1-neg68.3%

      \[\leadsto \frac{\left(-\left(x + -1\right)\right) \cdot \frac{2 + x}{x} + \color{blue}{\left(-\left(-1 - x\right)\right)}}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    4. unsub-neg68.3%

      \[\leadsto \frac{\color{blue}{\left(-\left(x + -1\right)\right) \cdot \frac{2 + x}{x} - \left(-1 - x\right)}}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    5. *-commutative68.3%

      \[\leadsto \frac{\color{blue}{\frac{2 + x}{x} \cdot \left(-\left(x + -1\right)\right)} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    6. associate-*l/19.9%

      \[\leadsto \frac{\color{blue}{\frac{\left(2 + x\right) \cdot \left(-\left(x + -1\right)\right)}{x}} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    7. associate-/l*68.3%

      \[\leadsto \frac{\color{blue}{\left(2 + x\right) \cdot \frac{-\left(x + -1\right)}{x}} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    8. distribute-neg-in68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{\color{blue}{\left(-x\right) + \left(--1\right)}}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    9. metadata-eval68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{\left(-x\right) + \color{blue}{1}}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    10. +-commutative68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{\color{blue}{1 + \left(-x\right)}}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    11. unsub-neg68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{\color{blue}{1 - x}}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(-\left(x + -1\right)\right)} \]
    12. distribute-neg-in68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{1 - x}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \color{blue}{\left(\left(-x\right) + \left(--1\right)\right)}} \]
    13. metadata-eval68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{1 - x}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(\left(-x\right) + \color{blue}{1}\right)} \]
    14. +-commutative68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{1 - x}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \color{blue}{\left(1 + \left(-x\right)\right)}} \]
    15. unsub-neg68.3%

      \[\leadsto \frac{\left(2 + x\right) \cdot \frac{1 - x}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \color{blue}{\left(1 - x\right)}} \]
  13. Simplified68.3%

    \[\leadsto \color{blue}{\frac{\left(2 + x\right) \cdot \frac{1 - x}{x} - \left(-1 - x\right)}{\left(-1 - x\right) \cdot \left(1 - x\right)}} \]
  14. Taylor expanded in x around 0 99.8%

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

Alternative 2: 68.4% accurate, 1.7× speedup?

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

\\
\frac{1}{x + -1} + \frac{-1}{x}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 66.0%

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

Alternative 3: 6.3% accurate, 2.1× speedup?

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

\\
\frac{1 + \frac{-1}{x}}{x}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub19.7%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-2 \cdot \left(-1 - x\right) - x \cdot 1}{x \cdot \left(-1 - x\right)}} \]
    2. associate-/r*68.3%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\frac{-2 \cdot \left(-1 - x\right) - x \cdot 1}{x}}{-1 - x}} \]
    3. *-rgt-identity68.3%

      \[\leadsto \frac{1}{x + -1} + \frac{\frac{-2 \cdot \left(-1 - x\right) - \color{blue}{x}}{x}}{-1 - x} \]
    4. fma-neg68.3%

      \[\leadsto \frac{1}{x + -1} + \frac{\frac{\color{blue}{\mathsf{fma}\left(-2, -1 - x, -x\right)}}{x}}{-1 - x} \]
  6. Applied egg-rr68.3%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\frac{\mathsf{fma}\left(-2, -1 - x, -x\right)}{x}}{-1 - x}} \]
  7. Taylor expanded in x around 0 6.3%

    \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{\frac{2}{x}}}{-1 - x} \]
  8. Taylor expanded in x around inf 6.3%

    \[\leadsto \color{blue}{\frac{1 - \frac{1}{x}}{x}} \]
  9. Final simplification6.3%

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

Alternative 4: 6.3% accurate, 5.0× speedup?

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

\\
\frac{1}{x}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-sub19.7%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-2 \cdot \left(-1 - x\right) - x \cdot 1}{x \cdot \left(-1 - x\right)}} \]
    2. associate-/r*68.3%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\frac{-2 \cdot \left(-1 - x\right) - x \cdot 1}{x}}{-1 - x}} \]
    3. *-rgt-identity68.3%

      \[\leadsto \frac{1}{x + -1} + \frac{\frac{-2 \cdot \left(-1 - x\right) - \color{blue}{x}}{x}}{-1 - x} \]
    4. fma-neg68.3%

      \[\leadsto \frac{1}{x + -1} + \frac{\frac{\color{blue}{\mathsf{fma}\left(-2, -1 - x, -x\right)}}{x}}{-1 - x} \]
  6. Applied egg-rr68.3%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{\frac{\mathsf{fma}\left(-2, -1 - x, -x\right)}{x}}{-1 - x}} \]
  7. Taylor expanded in x around 0 6.3%

    \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{\frac{2}{x}}}{-1 - x} \]
  8. Taylor expanded in x around inf 6.3%

    \[\leadsto \color{blue}{\frac{1}{x}} \]
  9. Add Preprocessing

Alternative 5: 5.1% accurate, 5.0× speedup?

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

\\
\frac{-1}{x}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 66.4%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{-1 \cdot \frac{1 + \frac{1}{x}}{x}} \]
  6. Step-by-step derivation
    1. associate-*r/66.4%

      \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-1 \cdot \left(1 + \frac{1}{x}\right)}{x}} \]
    2. neg-mul-166.4%

      \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{-\left(1 + \frac{1}{x}\right)}}{x} \]
    3. distribute-neg-in66.4%

      \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{\left(-1\right) + \left(-\frac{1}{x}\right)}}{x} \]
    4. metadata-eval66.4%

      \[\leadsto \frac{1}{x + -1} + \frac{\color{blue}{-1} + \left(-\frac{1}{x}\right)}{x} \]
    5. distribute-neg-frac66.4%

      \[\leadsto \frac{1}{x + -1} + \frac{-1 + \color{blue}{\frac{-1}{x}}}{x} \]
    6. metadata-eval66.4%

      \[\leadsto \frac{1}{x + -1} + \frac{-1 + \frac{\color{blue}{-1}}{x}}{x} \]
  7. Simplified66.4%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-1 + \frac{-1}{x}}{x}} \]
  8. Taylor expanded in x around 0 48.9%

    \[\leadsto \color{blue}{\frac{-1 \cdot x - 1}{{x}^{2}}} \]
  9. Step-by-step derivation
    1. sub-neg48.9%

      \[\leadsto \frac{\color{blue}{-1 \cdot x + \left(-1\right)}}{{x}^{2}} \]
    2. neg-mul-148.9%

      \[\leadsto \frac{\color{blue}{\left(-x\right)} + \left(-1\right)}{{x}^{2}} \]
    3. metadata-eval48.9%

      \[\leadsto \frac{\left(-x\right) + \color{blue}{-1}}{{x}^{2}} \]
    4. +-commutative48.9%

      \[\leadsto \frac{\color{blue}{-1 + \left(-x\right)}}{{x}^{2}} \]
    5. sub-neg48.9%

      \[\leadsto \frac{\color{blue}{-1 - x}}{{x}^{2}} \]
    6. unpow248.9%

      \[\leadsto \frac{-1 - x}{\color{blue}{x \cdot x}} \]
    7. associate-/r*4.9%

      \[\leadsto \color{blue}{\frac{\frac{-1 - x}{x}}{x}} \]
    8. sub-neg4.9%

      \[\leadsto \frac{\frac{\color{blue}{-1 + \left(-x\right)}}{x}}{x} \]
    9. +-commutative4.9%

      \[\leadsto \frac{\frac{\color{blue}{\left(-x\right) + -1}}{x}}{x} \]
    10. metadata-eval4.9%

      \[\leadsto \frac{\frac{\left(-x\right) + \color{blue}{\left(-1\right)}}{x}}{x} \]
    11. neg-mul-14.9%

      \[\leadsto \frac{\frac{\color{blue}{-1 \cdot x} + \left(-1\right)}{x}}{x} \]
    12. sub-neg4.9%

      \[\leadsto \frac{\frac{\color{blue}{-1 \cdot x - 1}}{x}}{x} \]
    13. div-sub4.9%

      \[\leadsto \frac{\color{blue}{\frac{-1 \cdot x}{x} - \frac{1}{x}}}{x} \]
    14. associate-/l*4.9%

      \[\leadsto \frac{\color{blue}{-1 \cdot \frac{x}{x}} - \frac{1}{x}}{x} \]
    15. *-inverses4.9%

      \[\leadsto \frac{-1 \cdot \color{blue}{1} - \frac{1}{x}}{x} \]
    16. metadata-eval4.9%

      \[\leadsto \frac{\color{blue}{-1} - \frac{1}{x}}{x} \]
  10. Simplified4.9%

    \[\leadsto \color{blue}{\frac{-1 - \frac{1}{x}}{x}} \]
  11. Taylor expanded in x around inf 4.9%

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

Alternative 6: 5.1% accurate, 5.0× speedup?

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

\\
\frac{-2}{x}
\end{array}
Derivation
  1. Initial program 68.3%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg68.2%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-68.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub068.2%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg268.2%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+68.3%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative68.3%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg68.3%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac268.3%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-68.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub068.3%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified68.3%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 4.9%

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

Developer Target 1: 99.2% accurate, 1.7× speedup?

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

\\
\frac{2}{x \cdot \left(x \cdot x - 1\right)}
\end{array}

Reproduce

?
herbie shell --seed 2024121 
(FPCore (x)
  :name "3frac (problem 3.3.3)"
  :precision binary64
  :pre (> (fabs x) 1.0)

  :alt
  (! :herbie-platform default (/ 2 (* x (- (* x x) 1))))

  (+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (- x 1.0))))