3frac (problem 3.3.3)

Percentage Accurate: 68.9% → 99.7%
Time: 11.5s
Alternatives: 8
Speedup: 1.0×

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 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 68.9% 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: 99.7% accurate, 0.0× speedup?

\[\begin{array}{l} \\ \left(2 + 2 \cdot \left(\frac{1}{x} \cdot \frac{1}{x} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \end{array} \]
(FPCore (x)
 :precision binary64
 (*
  (+ 2.0 (* 2.0 (+ (* (/ 1.0 x) (/ 1.0 x)) (+ (pow x -6.0) (pow x -4.0)))))
  (pow x -3.0)))
double code(double x) {
	return (2.0 + (2.0 * (((1.0 / x) * (1.0 / x)) + (pow(x, -6.0) + pow(x, -4.0))))) * pow(x, -3.0);
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (2.0d0 + (2.0d0 * (((1.0d0 / x) * (1.0d0 / x)) + ((x ** (-6.0d0)) + (x ** (-4.0d0)))))) * (x ** (-3.0d0))
end function
public static double code(double x) {
	return (2.0 + (2.0 * (((1.0 / x) * (1.0 / x)) + (Math.pow(x, -6.0) + Math.pow(x, -4.0))))) * Math.pow(x, -3.0);
}
def code(x):
	return (2.0 + (2.0 * (((1.0 / x) * (1.0 / x)) + (math.pow(x, -6.0) + math.pow(x, -4.0))))) * math.pow(x, -3.0)
function code(x)
	return Float64(Float64(2.0 + Float64(2.0 * Float64(Float64(Float64(1.0 / x) * Float64(1.0 / x)) + Float64((x ^ -6.0) + (x ^ -4.0))))) * (x ^ -3.0))
end
function tmp = code(x)
	tmp = (2.0 + (2.0 * (((1.0 / x) * (1.0 / x)) + ((x ^ -6.0) + (x ^ -4.0))))) * (x ^ -3.0);
end
code[x_] := N[(N[(2.0 + N[(2.0 * N[(N[(N[(1.0 / x), $MachinePrecision] * N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + N[(N[Power[x, -6.0], $MachinePrecision] + N[Power[x, -4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Power[x, -3.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(2 + 2 \cdot \left(\frac{1}{x} \cdot \frac{1}{x} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 98.2%

    \[\leadsto \color{blue}{\frac{2 + \left(2 \cdot \frac{1}{{x}^{2}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}}} \]
  6. Step-by-step derivation
    1. associate-*r/98.2%

      \[\leadsto \frac{2 + \left(\color{blue}{\frac{2 \cdot 1}{{x}^{2}}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}} \]
    2. metadata-eval98.2%

      \[\leadsto \frac{2 + \left(\frac{\color{blue}{2}}{{x}^{2}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}} \]
    3. +-commutative98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \color{blue}{\left(\frac{2}{{x}^{4}} + 2 \cdot \frac{1}{{x}^{6}}\right)}\right)}{{x}^{3}} \]
    4. associate-*r/98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \color{blue}{\frac{2 \cdot 1}{{x}^{6}}}\right)\right)}{{x}^{3}} \]
    5. metadata-eval98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{\color{blue}{2}}{{x}^{6}}\right)\right)}{{x}^{3}} \]
  7. Simplified98.2%

    \[\leadsto \color{blue}{\frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)}{{x}^{3}}} \]
  8. Step-by-step derivation
    1. div-inv98.2%

      \[\leadsto \color{blue}{\left(2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)\right) \cdot \frac{1}{{x}^{3}}} \]
    2. div-inv98.2%

      \[\leadsto \left(2 + \left(\color{blue}{2 \cdot \frac{1}{{x}^{2}}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    3. fma-define98.2%

      \[\leadsto \left(2 + \color{blue}{\mathsf{fma}\left(2, \frac{1}{{x}^{2}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)}\right) \cdot \frac{1}{{x}^{3}} \]
    4. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, \color{blue}{{x}^{\left(-2\right)}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    5. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{\color{blue}{-2}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    6. +-commutative98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{\frac{2}{{x}^{6}} + \frac{2}{{x}^{4}}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    7. div-inv98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot \frac{1}{{x}^{6}}} + \frac{2}{{x}^{4}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    8. fma-define98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{\mathsf{fma}\left(2, \frac{1}{{x}^{6}}, \frac{2}{{x}^{4}}\right)}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    9. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, \color{blue}{{x}^{\left(-6\right)}}, \frac{2}{{x}^{4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    10. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{\color{blue}{-6}}, \frac{2}{{x}^{4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    11. div-inv98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, \color{blue}{2 \cdot \frac{1}{{x}^{4}}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    12. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot \color{blue}{{x}^{\left(-4\right)}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    13. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{\color{blue}{-4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    14. pow-flip99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot \color{blue}{{x}^{\left(-3\right)}} \]
    15. metadata-eval99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot {x}^{\color{blue}{-3}} \]
  9. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot {x}^{-3}} \]
  10. Step-by-step derivation
    1. fma-undefine99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot {x}^{-6} + 2 \cdot {x}^{-4}}\right)\right) \cdot {x}^{-3} \]
    2. distribute-lft-out99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot \left({x}^{-6} + {x}^{-4}\right)}\right)\right) \cdot {x}^{-3} \]
  11. Simplified99.6%

    \[\leadsto \color{blue}{\left(2 + \mathsf{fma}\left(2, {x}^{-2}, 2 \cdot \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3}} \]
  12. Step-by-step derivation
    1. fma-undefine99.6%

      \[\leadsto \left(2 + \color{blue}{\left(2 \cdot {x}^{-2} + 2 \cdot \left({x}^{-6} + {x}^{-4}\right)\right)}\right) \cdot {x}^{-3} \]
  13. Applied egg-rr99.6%

    \[\leadsto \left(2 + \color{blue}{\left(2 \cdot {x}^{-2} + 2 \cdot \left({x}^{-6} + {x}^{-4}\right)\right)}\right) \cdot {x}^{-3} \]
  14. Step-by-step derivation
    1. distribute-lft-out99.6%

      \[\leadsto \left(2 + \color{blue}{2 \cdot \left({x}^{-2} + \left({x}^{-6} + {x}^{-4}\right)\right)}\right) \cdot {x}^{-3} \]
  15. Simplified99.6%

    \[\leadsto \left(2 + \color{blue}{2 \cdot \left({x}^{-2} + \left({x}^{-6} + {x}^{-4}\right)\right)}\right) \cdot {x}^{-3} \]
  16. Step-by-step derivation
    1. metadata-eval99.6%

      \[\leadsto \left(2 + 2 \cdot \left({x}^{\color{blue}{\left(-1 + -1\right)}} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \]
    2. pow-prod-up99.6%

      \[\leadsto \left(2 + 2 \cdot \left(\color{blue}{{x}^{-1} \cdot {x}^{-1}} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \]
    3. inv-pow99.6%

      \[\leadsto \left(2 + 2 \cdot \left(\color{blue}{\frac{1}{x}} \cdot {x}^{-1} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \]
    4. inv-pow99.6%

      \[\leadsto \left(2 + 2 \cdot \left(\frac{1}{x} \cdot \color{blue}{\frac{1}{x}} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \]
  17. Applied egg-rr99.6%

    \[\leadsto \left(2 + 2 \cdot \left(\color{blue}{\frac{1}{x} \cdot \frac{1}{x}} + \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3} \]
  18. Add Preprocessing

Alternative 2: 99.0% accurate, 0.1× speedup?

\[\begin{array}{l} \\ 2 \cdot {x}^{-3} \end{array} \]
(FPCore (x) :precision binary64 (* 2.0 (pow x -3.0)))
double code(double x) {
	return 2.0 * pow(x, -3.0);
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 2.0d0 * (x ** (-3.0d0))
end function
public static double code(double x) {
	return 2.0 * Math.pow(x, -3.0);
}
def code(x):
	return 2.0 * math.pow(x, -3.0)
function code(x)
	return Float64(2.0 * (x ^ -3.0))
end
function tmp = code(x)
	tmp = 2.0 * (x ^ -3.0);
end
code[x_] := N[(2.0 * N[Power[x, -3.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
2 \cdot {x}^{-3}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 98.2%

    \[\leadsto \color{blue}{\frac{2 + \left(2 \cdot \frac{1}{{x}^{2}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}}} \]
  6. Step-by-step derivation
    1. associate-*r/98.2%

      \[\leadsto \frac{2 + \left(\color{blue}{\frac{2 \cdot 1}{{x}^{2}}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}} \]
    2. metadata-eval98.2%

      \[\leadsto \frac{2 + \left(\frac{\color{blue}{2}}{{x}^{2}} + \left(2 \cdot \frac{1}{{x}^{6}} + \frac{2}{{x}^{4}}\right)\right)}{{x}^{3}} \]
    3. +-commutative98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \color{blue}{\left(\frac{2}{{x}^{4}} + 2 \cdot \frac{1}{{x}^{6}}\right)}\right)}{{x}^{3}} \]
    4. associate-*r/98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \color{blue}{\frac{2 \cdot 1}{{x}^{6}}}\right)\right)}{{x}^{3}} \]
    5. metadata-eval98.2%

      \[\leadsto \frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{\color{blue}{2}}{{x}^{6}}\right)\right)}{{x}^{3}} \]
  7. Simplified98.2%

    \[\leadsto \color{blue}{\frac{2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)}{{x}^{3}}} \]
  8. Step-by-step derivation
    1. div-inv98.2%

      \[\leadsto \color{blue}{\left(2 + \left(\frac{2}{{x}^{2}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)\right) \cdot \frac{1}{{x}^{3}}} \]
    2. div-inv98.2%

      \[\leadsto \left(2 + \left(\color{blue}{2 \cdot \frac{1}{{x}^{2}}} + \left(\frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    3. fma-define98.2%

      \[\leadsto \left(2 + \color{blue}{\mathsf{fma}\left(2, \frac{1}{{x}^{2}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)}\right) \cdot \frac{1}{{x}^{3}} \]
    4. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, \color{blue}{{x}^{\left(-2\right)}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    5. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{\color{blue}{-2}}, \frac{2}{{x}^{4}} + \frac{2}{{x}^{6}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    6. +-commutative98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{\frac{2}{{x}^{6}} + \frac{2}{{x}^{4}}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    7. div-inv98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot \frac{1}{{x}^{6}}} + \frac{2}{{x}^{4}}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    8. fma-define98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{\mathsf{fma}\left(2, \frac{1}{{x}^{6}}, \frac{2}{{x}^{4}}\right)}\right)\right) \cdot \frac{1}{{x}^{3}} \]
    9. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, \color{blue}{{x}^{\left(-6\right)}}, \frac{2}{{x}^{4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    10. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{\color{blue}{-6}}, \frac{2}{{x}^{4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    11. div-inv98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, \color{blue}{2 \cdot \frac{1}{{x}^{4}}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    12. pow-flip98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot \color{blue}{{x}^{\left(-4\right)}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    13. metadata-eval98.2%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{\color{blue}{-4}}\right)\right)\right) \cdot \frac{1}{{x}^{3}} \]
    14. pow-flip99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot \color{blue}{{x}^{\left(-3\right)}} \]
    15. metadata-eval99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot {x}^{\color{blue}{-3}} \]
  9. Applied egg-rr99.6%

    \[\leadsto \color{blue}{\left(2 + \mathsf{fma}\left(2, {x}^{-2}, \mathsf{fma}\left(2, {x}^{-6}, 2 \cdot {x}^{-4}\right)\right)\right) \cdot {x}^{-3}} \]
  10. Step-by-step derivation
    1. fma-undefine99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot {x}^{-6} + 2 \cdot {x}^{-4}}\right)\right) \cdot {x}^{-3} \]
    2. distribute-lft-out99.6%

      \[\leadsto \left(2 + \mathsf{fma}\left(2, {x}^{-2}, \color{blue}{2 \cdot \left({x}^{-6} + {x}^{-4}\right)}\right)\right) \cdot {x}^{-3} \]
  11. Simplified99.6%

    \[\leadsto \color{blue}{\left(2 + \mathsf{fma}\left(2, {x}^{-2}, 2 \cdot \left({x}^{-6} + {x}^{-4}\right)\right)\right) \cdot {x}^{-3}} \]
  12. Taylor expanded in x around inf 98.9%

    \[\leadsto \color{blue}{2} \cdot {x}^{-3} \]
  13. Add Preprocessing

Alternative 3: 68.9% accurate, 1.0× speedup?

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

\\
\left(\frac{1}{1 + x} - \frac{2}{x}\right) + \frac{1}{x + -1}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Add Preprocessing
  3. Final simplification66.6%

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

Alternative 4: 67.5% accurate, 1.4× speedup?

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

\\
\frac{1 + \frac{1}{x}}{x} + \frac{-1}{x}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 65.5%

    \[\leadsto \color{blue}{\frac{1 + \frac{1}{x}}{x}} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right) \]
  6. Taylor expanded in x around inf 65.4%

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

Alternative 5: 67.6% accurate, 1.7× speedup?

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

\\
\frac{-1}{x} + \frac{1}{x + -1}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 65.4%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-1}{x}} \]
  6. Final simplification65.4%

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

Alternative 6: 67.4% accurate, 2.1× speedup?

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

\\
\frac{1}{x} + \frac{-1}{x}
\end{array}
Derivation
  1. Initial program 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 65.4%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-1}{x}} \]
  6. Taylor expanded in x around inf 65.2%

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

Alternative 7: 5.0% 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 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

    \[\leadsto \color{blue}{\frac{1}{x + -1} + \left(\frac{-2}{x} - \frac{1}{-1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 65.4%

    \[\leadsto \frac{1}{x + -1} + \color{blue}{\frac{-1}{x}} \]
  6. Taylor expanded in x around 0 4.8%

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

Alternative 8: 5.0% 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 66.6%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. +-commutative66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\frac{1}{x + 1} - \frac{2}{x}\right)} \]
    2. associate-+r-66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}} \]
    3. sub-neg66.6%

      \[\leadsto \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) + \left(-\frac{2}{x}\right)} \]
    4. remove-double-neg66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(-\left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    5. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{\left(0 - \left(-x\right)\right)} + 1}\right) + \left(-\frac{2}{x}\right) \]
    6. associate-+l-66.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{0 - \left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    7. neg-sub066.6%

      \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{\color{blue}{-\left(\left(-x\right) - 1\right)}}\right) + \left(-\frac{2}{x}\right) \]
    8. distribute-neg-frac266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \color{blue}{\left(-\frac{1}{\left(-x\right) - 1}\right)}\right) + \left(-\frac{2}{x}\right) \]
    9. distribute-frac-neg266.6%

      \[\leadsto \left(\frac{1}{x - 1} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) + \color{blue}{\frac{2}{-x}} \]
    10. associate-+r+66.6%

      \[\leadsto \color{blue}{\frac{1}{x - 1} + \left(\left(-\frac{1}{\left(-x\right) - 1}\right) + \frac{2}{-x}\right)} \]
    11. +-commutative66.6%

      \[\leadsto \frac{1}{x - 1} + \color{blue}{\left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right)} \]
    12. remove-double-neg66.6%

      \[\leadsto \color{blue}{\left(-\left(-\frac{1}{x - 1}\right)\right)} + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    13. distribute-neg-frac266.6%

      \[\leadsto \left(-\color{blue}{\frac{1}{-\left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    14. sub0-neg66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{0 - \left(x - 1\right)}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    15. associate-+l-66.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(0 - x\right) + 1}}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
    16. neg-sub066.6%

      \[\leadsto \left(-\frac{1}{\color{blue}{\left(-x\right)} + 1}\right) + \left(\frac{2}{-x} + \left(-\frac{1}{\left(-x\right) - 1}\right)\right) \]
  3. Simplified66.6%

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

    \[\leadsto \color{blue}{\frac{-2}{x}} \]
  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 2024185 
(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))))