3frac (problem 3.3.3)

Percentage Accurate: 69.1% → 98.9%
Time: 8.7s
Alternatives: 10
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 10 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: 69.1% 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: 98.9% 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 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.4%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.4%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.4%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.4%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.4%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.4%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.4%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.4%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.4%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 98.4%

    \[\leadsto \color{blue}{\frac{2}{{x}^{3}}} \]
  6. Step-by-step derivation
    1. expm1-log1p-u98.4%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)\right)} \]
    2. expm1-udef67.2%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)} - 1} \]
    3. div-inv67.2%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{2 \cdot \frac{1}{{x}^{3}}}\right)} - 1 \]
    4. pow-flip67.2%

      \[\leadsto e^{\mathsf{log1p}\left(2 \cdot \color{blue}{{x}^{\left(-3\right)}}\right)} - 1 \]
    5. metadata-eval67.2%

      \[\leadsto e^{\mathsf{log1p}\left(2 \cdot {x}^{\color{blue}{-3}}\right)} - 1 \]
  7. Applied egg-rr67.2%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(2 \cdot {x}^{-3}\right)} - 1} \]
  8. Step-by-step derivation
    1. expm1-def98.8%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(2 \cdot {x}^{-3}\right)\right)} \]
    2. expm1-log1p98.8%

      \[\leadsto \color{blue}{2 \cdot {x}^{-3}} \]
  9. Simplified98.8%

    \[\leadsto \color{blue}{2 \cdot {x}^{-3}} \]
  10. Final simplification98.8%

    \[\leadsto 2 \cdot {x}^{-3} \]
  11. Add Preprocessing

Alternative 2: 68.8% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(x + -1\right) \cdot \left(x + 1\right)\\ \mathbf{if}\;\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x + -1} \leq 4 \cdot 10^{-28}:\\ \;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{x \cdot \left(x + x\right) + t_0 \cdot -2}{x \cdot t_0}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (* (+ x -1.0) (+ x 1.0))))
   (if (<= (+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (+ x -1.0))) 4e-28)
     (+ (/ -2.0 x) (+ (/ 1.0 x) (/ -1.0 (- 1.0 x))))
     (/ (+ (* x (+ x x)) (* t_0 -2.0)) (* x t_0)))))
double code(double x) {
	double t_0 = (x + -1.0) * (x + 1.0);
	double tmp;
	if ((((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x + -1.0))) <= 4e-28) {
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	} else {
		tmp = ((x * (x + x)) + (t_0 * -2.0)) / (x * t_0);
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (x + (-1.0d0)) * (x + 1.0d0)
    if ((((1.0d0 / (x + 1.0d0)) - (2.0d0 / x)) + (1.0d0 / (x + (-1.0d0)))) <= 4d-28) then
        tmp = ((-2.0d0) / x) + ((1.0d0 / x) + ((-1.0d0) / (1.0d0 - x)))
    else
        tmp = ((x * (x + x)) + (t_0 * (-2.0d0))) / (x * t_0)
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = (x + -1.0) * (x + 1.0);
	double tmp;
	if ((((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x + -1.0))) <= 4e-28) {
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	} else {
		tmp = ((x * (x + x)) + (t_0 * -2.0)) / (x * t_0);
	}
	return tmp;
}
def code(x):
	t_0 = (x + -1.0) * (x + 1.0)
	tmp = 0
	if (((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x + -1.0))) <= 4e-28:
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)))
	else:
		tmp = ((x * (x + x)) + (t_0 * -2.0)) / (x * t_0)
	return tmp
function code(x)
	t_0 = Float64(Float64(x + -1.0) * Float64(x + 1.0))
	tmp = 0.0
	if (Float64(Float64(Float64(1.0 / Float64(x + 1.0)) - Float64(2.0 / x)) + Float64(1.0 / Float64(x + -1.0))) <= 4e-28)
		tmp = Float64(Float64(-2.0 / x) + Float64(Float64(1.0 / x) + Float64(-1.0 / Float64(1.0 - x))));
	else
		tmp = Float64(Float64(Float64(x * Float64(x + x)) + Float64(t_0 * -2.0)) / Float64(x * t_0));
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = (x + -1.0) * (x + 1.0);
	tmp = 0.0;
	if ((((1.0 / (x + 1.0)) - (2.0 / x)) + (1.0 / (x + -1.0))) <= 4e-28)
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	else
		tmp = ((x * (x + x)) + (t_0 * -2.0)) / (x * t_0);
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(N[(x + -1.0), $MachinePrecision] * N[(x + 1.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[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], 4e-28], N[(N[(-2.0 / x), $MachinePrecision] + N[(N[(1.0 / x), $MachinePrecision] + N[(-1.0 / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x * N[(x + x), $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * -2.0), $MachinePrecision]), $MachinePrecision] / N[(x * t$95$0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(x + -1\right) \cdot \left(x + 1\right)\\
\mathbf{if}\;\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x + -1} \leq 4 \cdot 10^{-28}:\\
\;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{x \cdot \left(x + x\right) + t_0 \cdot -2}{x \cdot t_0}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (+.f64 (-.f64 (/.f64 1 (+.f64 x 1)) (/.f64 2 x)) (/.f64 1 (-.f64 x 1))) < 3.99999999999999988e-28

    1. Initial program 68.9%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg68.9%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac68.9%

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

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

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

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*68.9%

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

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-168.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative68.9%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+68.8%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative68.8%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-168.8%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval68.8%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*68.8%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval68.8%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval68.8%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative68.8%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative68.8%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    3. Simplified68.8%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 67.8%

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

    if 3.99999999999999988e-28 < (+.f64 (-.f64 (/.f64 1 (+.f64 x 1)) (/.f64 2 x)) (/.f64 1 (-.f64 x 1)))

    1. Initial program 45.4%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg45.4%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
      3. metadata-eval45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
      4. metadata-eval45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      5. metadata-eval45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
      7. metadata-eval45.4%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-145.4%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative45.4%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+45.2%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative45.2%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-145.2%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval45.2%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*45.2%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval45.2%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval45.2%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative45.2%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative45.2%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    3. Simplified45.2%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg45.2%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \color{blue}{\frac{--1}{-\left(1 - x\right)}}\right) \]
      2. metadata-eval45.2%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{\color{blue}{1}}{-\left(1 - x\right)}\right) \]
      3. frac-add41.2%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1 \cdot \left(-\left(1 - x\right)\right) + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)}} \]
      4. *-un-lft-identity41.2%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(-\left(1 - x\right)\right)} + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      5. *-commutative41.2%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \color{blue}{1 \cdot \left(1 + x\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      6. +-commutative41.2%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + 1 \cdot \color{blue}{\left(x + 1\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      7. *-un-lft-identity41.2%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \color{blue}{\left(x + 1\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      8. +-commutative41.2%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{\color{blue}{\left(x + 1\right)} \cdot \left(-\left(1 - x\right)\right)} \]
    6. Applied egg-rr41.2%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{\left(x + 1\right) \cdot \left(-\left(1 - x\right)\right)}} \]
    7. Step-by-step derivation
      1. associate-/r*41.7%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)}} \]
      2. neg-sub041.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(0 - \left(1 - x\right)\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      3. associate--r-41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(\left(0 - 1\right) + x\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      4. metadata-eval41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(\color{blue}{-1} + x\right) + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      5. +-commutative41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(x + -1\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      6. neg-sub041.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{0 - \left(1 - x\right)}} \]
      7. associate--r-41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{\left(0 - 1\right) + x}} \]
      8. metadata-eval41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{-1} + x} \]
      9. +-commutative41.7%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{x + -1}} \]
      10. associate-/r*41.2%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(x + -1\right) + \left(x + 1\right)}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
      11. +-commutative41.2%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(x + 1\right) + \left(x + -1\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      12. associate-+l+41.2%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{x + \left(1 + \left(x + -1\right)\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      13. +-commutative41.2%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(1 + \color{blue}{\left(-1 + x\right)}\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      14. associate-+r+41.2%

        \[\leadsto \frac{-2}{x} + \frac{x + \color{blue}{\left(\left(1 + -1\right) + x\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      15. metadata-eval41.2%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(\color{blue}{0} + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    8. Simplified41.2%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    9. Step-by-step derivation
      1. +-commutative41.2%

        \[\leadsto \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} + \frac{-2}{x}} \]
      2. frac-add80.0%

        \[\leadsto \color{blue}{\frac{\left(x + \left(0 + x\right)\right) \cdot x + \left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x}} \]
      3. +-lft-identity80.0%

        \[\leadsto \frac{\left(x + \color{blue}{x}\right) \cdot x + \left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      4. +-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\color{blue}{\left(1 + x\right)} \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      5. *-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \color{blue}{\left(\left(x + -1\right) \cdot \left(1 + x\right)\right)} \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      6. +-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \color{blue}{\left(x + 1\right)}\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      7. +-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\color{blue}{\left(1 + x\right)} \cdot \left(x + -1\right)\right) \cdot x} \]
      8. *-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\color{blue}{\left(\left(x + -1\right) \cdot \left(1 + x\right)\right)} \cdot x} \]
      9. +-commutative80.0%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\left(x + -1\right) \cdot \color{blue}{\left(x + 1\right)}\right) \cdot x} \]
    10. Applied egg-rr80.0%

      \[\leadsto \color{blue}{\frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot x}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification68.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x + -1} \leq 4 \cdot 10^{-28}:\\ \;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{x \cdot \left(x + x\right) + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{x \cdot \left(\left(x + -1\right) \cdot \left(x + 1\right)\right)}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 45.2% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot \left(x + -1\right)\\ \mathbf{if}\;x \leq 140000000:\\ \;\;\;\;\frac{x \cdot \left(x + x\right) + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{t_0 + x \cdot t_0}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (* x (+ x -1.0))))
   (if (<= x 140000000.0)
     (/ (+ (* x (+ x x)) (* (* (+ x -1.0) (+ x 1.0)) -2.0)) (+ t_0 (* x t_0)))
     (+ (/ -2.0 x) (+ (/ 1.0 x) (/ -1.0 (- 1.0 x)))))))
double code(double x) {
	double t_0 = x * (x + -1.0);
	double tmp;
	if (x <= 140000000.0) {
		tmp = ((x * (x + x)) + (((x + -1.0) * (x + 1.0)) * -2.0)) / (t_0 + (x * t_0));
	} else {
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = x * (x + (-1.0d0))
    if (x <= 140000000.0d0) then
        tmp = ((x * (x + x)) + (((x + (-1.0d0)) * (x + 1.0d0)) * (-2.0d0))) / (t_0 + (x * t_0))
    else
        tmp = ((-2.0d0) / x) + ((1.0d0 / x) + ((-1.0d0) / (1.0d0 - x)))
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = x * (x + -1.0);
	double tmp;
	if (x <= 140000000.0) {
		tmp = ((x * (x + x)) + (((x + -1.0) * (x + 1.0)) * -2.0)) / (t_0 + (x * t_0));
	} else {
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	}
	return tmp;
}
def code(x):
	t_0 = x * (x + -1.0)
	tmp = 0
	if x <= 140000000.0:
		tmp = ((x * (x + x)) + (((x + -1.0) * (x + 1.0)) * -2.0)) / (t_0 + (x * t_0))
	else:
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)))
	return tmp
function code(x)
	t_0 = Float64(x * Float64(x + -1.0))
	tmp = 0.0
	if (x <= 140000000.0)
		tmp = Float64(Float64(Float64(x * Float64(x + x)) + Float64(Float64(Float64(x + -1.0) * Float64(x + 1.0)) * -2.0)) / Float64(t_0 + Float64(x * t_0)));
	else
		tmp = Float64(Float64(-2.0 / x) + Float64(Float64(1.0 / x) + Float64(-1.0 / Float64(1.0 - x))));
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = x * (x + -1.0);
	tmp = 0.0;
	if (x <= 140000000.0)
		tmp = ((x * (x + x)) + (((x + -1.0) * (x + 1.0)) * -2.0)) / (t_0 + (x * t_0));
	else
		tmp = (-2.0 / x) + ((1.0 / x) + (-1.0 / (1.0 - x)));
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(x * N[(x + -1.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, 140000000.0], N[(N[(N[(x * N[(x + x), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(x + -1.0), $MachinePrecision] * N[(x + 1.0), $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision] / N[(t$95$0 + N[(x * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-2.0 / x), $MachinePrecision] + N[(N[(1.0 / x), $MachinePrecision] + N[(-1.0 / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot \left(x + -1\right)\\
\mathbf{if}\;x \leq 140000000:\\
\;\;\;\;\frac{x \cdot \left(x + x\right) + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{t_0 + x \cdot t_0}\\

\mathbf{else}:\\
\;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 1.4e8

    1. Initial program 69.8%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg69.8%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
      3. metadata-eval69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
      4. metadata-eval69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      5. metadata-eval69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
      7. metadata-eval69.8%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-169.8%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative69.8%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+69.7%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative69.7%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-169.7%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval69.7%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*69.7%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval69.7%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval69.7%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative69.7%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative69.7%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    3. Simplified69.7%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-2neg69.7%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \color{blue}{\frac{--1}{-\left(1 - x\right)}}\right) \]
      2. metadata-eval69.7%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{\color{blue}{1}}{-\left(1 - x\right)}\right) \]
      3. frac-add16.9%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1 \cdot \left(-\left(1 - x\right)\right) + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)}} \]
      4. *-un-lft-identity16.9%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(-\left(1 - x\right)\right)} + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      5. *-commutative16.9%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \color{blue}{1 \cdot \left(1 + x\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      6. +-commutative16.9%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + 1 \cdot \color{blue}{\left(x + 1\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      7. *-un-lft-identity16.9%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \color{blue}{\left(x + 1\right)}}{\left(1 + x\right) \cdot \left(-\left(1 - x\right)\right)} \]
      8. +-commutative16.9%

        \[\leadsto \frac{-2}{x} + \frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{\color{blue}{\left(x + 1\right)} \cdot \left(-\left(1 - x\right)\right)} \]
    6. Applied egg-rr16.9%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{\left(x + 1\right) \cdot \left(-\left(1 - x\right)\right)}} \]
    7. Step-by-step derivation
      1. associate-/r*68.8%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\frac{\left(-\left(1 - x\right)\right) + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)}} \]
      2. neg-sub068.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(0 - \left(1 - x\right)\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      3. associate--r-68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(\left(0 - 1\right) + x\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      4. metadata-eval68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(\color{blue}{-1} + x\right) + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      5. +-commutative68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\color{blue}{\left(x + -1\right)} + \left(x + 1\right)}{x + 1}}{-\left(1 - x\right)} \]
      6. neg-sub068.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{0 - \left(1 - x\right)}} \]
      7. associate--r-68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{\left(0 - 1\right) + x}} \]
      8. metadata-eval68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{-1} + x} \]
      9. +-commutative68.8%

        \[\leadsto \frac{-2}{x} + \frac{\frac{\left(x + -1\right) + \left(x + 1\right)}{x + 1}}{\color{blue}{x + -1}} \]
      10. associate-/r*16.9%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(x + -1\right) + \left(x + 1\right)}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
      11. +-commutative16.9%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(x + 1\right) + \left(x + -1\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      12. associate-+l+16.9%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{x + \left(1 + \left(x + -1\right)\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      13. +-commutative16.9%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(1 + \color{blue}{\left(-1 + x\right)}\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      14. associate-+r+16.9%

        \[\leadsto \frac{-2}{x} + \frac{x + \color{blue}{\left(\left(1 + -1\right) + x\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      15. metadata-eval16.9%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(\color{blue}{0} + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    8. Simplified16.9%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    9. Step-by-step derivation
      1. +-commutative16.9%

        \[\leadsto \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} + \frac{-2}{x}} \]
      2. frac-add17.1%

        \[\leadsto \color{blue}{\frac{\left(x + \left(0 + x\right)\right) \cdot x + \left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x}} \]
      3. +-lft-identity17.1%

        \[\leadsto \frac{\left(x + \color{blue}{x}\right) \cdot x + \left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      4. +-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\color{blue}{\left(1 + x\right)} \cdot \left(x + -1\right)\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      5. *-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \color{blue}{\left(\left(x + -1\right) \cdot \left(1 + x\right)\right)} \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      6. +-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \color{blue}{\left(x + 1\right)}\right) \cdot -2}{\left(\left(x + 1\right) \cdot \left(x + -1\right)\right) \cdot x} \]
      7. +-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\color{blue}{\left(1 + x\right)} \cdot \left(x + -1\right)\right) \cdot x} \]
      8. *-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\color{blue}{\left(\left(x + -1\right) \cdot \left(1 + x\right)\right)} \cdot x} \]
      9. +-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\left(x + -1\right) \cdot \color{blue}{\left(x + 1\right)}\right) \cdot x} \]
    10. Applied egg-rr17.1%

      \[\leadsto \color{blue}{\frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot x}} \]
    11. Step-by-step derivation
      1. *-commutative17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\color{blue}{x \cdot \left(\left(x + -1\right) \cdot \left(x + 1\right)\right)}} \]
      2. distribute-lft-in17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{x \cdot \color{blue}{\left(\left(x + -1\right) \cdot x + \left(x + -1\right) \cdot 1\right)}} \]
      3. *-rgt-identity17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{x \cdot \left(\left(x + -1\right) \cdot x + \color{blue}{\left(x + -1\right)}\right)} \]
      4. distribute-rgt-in17.1%

        \[\leadsto \frac{\left(x + x\right) \cdot x + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{\color{blue}{\left(\left(x + -1\right) \cdot x\right) \cdot x + \left(x + -1\right) \cdot x}} \]
    12. Applied egg-rr17.1%

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

    if 1.4e8 < x

    1. Initial program 66.9%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg66.9%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
      3. metadata-eval66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
      4. metadata-eval66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      5. metadata-eval66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
      7. metadata-eval66.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-166.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative66.9%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+66.8%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative66.8%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-166.8%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval66.8%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*66.8%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval66.8%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval66.8%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative66.8%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative66.8%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    3. Simplified66.8%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 67.0%

      \[\leadsto \frac{-2}{x} + \left(\color{blue}{\frac{1}{x}} + \frac{-1}{1 - x}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification39.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 140000000:\\ \;\;\;\;\frac{x \cdot \left(x + x\right) + \left(\left(x + -1\right) \cdot \left(x + 1\right)\right) \cdot -2}{x \cdot \left(x + -1\right) + x \cdot \left(x \cdot \left(x + -1\right)\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 69.1% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \frac{1}{x + 1} + \frac{\frac{-1 + x \cdot 0.5}{x + -1}}{x \cdot -0.5} \end{array} \]
(FPCore (x)
 :precision binary64
 (+ (/ 1.0 (+ x 1.0)) (/ (/ (+ -1.0 (* x 0.5)) (+ x -1.0)) (* x -0.5))))
double code(double x) {
	return (1.0 / (x + 1.0)) + (((-1.0 + (x * 0.5)) / (x + -1.0)) / (x * -0.5));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (1.0d0 / (x + 1.0d0)) + ((((-1.0d0) + (x * 0.5d0)) / (x + (-1.0d0))) / (x * (-0.5d0)))
end function
public static double code(double x) {
	return (1.0 / (x + 1.0)) + (((-1.0 + (x * 0.5)) / (x + -1.0)) / (x * -0.5));
}
def code(x):
	return (1.0 / (x + 1.0)) + (((-1.0 + (x * 0.5)) / (x + -1.0)) / (x * -0.5))
function code(x)
	return Float64(Float64(1.0 / Float64(x + 1.0)) + Float64(Float64(Float64(-1.0 + Float64(x * 0.5)) / Float64(x + -1.0)) / Float64(x * -0.5)))
end
function tmp = code(x)
	tmp = (1.0 / (x + 1.0)) + (((-1.0 + (x * 0.5)) / (x + -1.0)) / (x * -0.5));
end
code[x_] := N[(N[(1.0 / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(-1.0 + N[(x * 0.5), $MachinePrecision]), $MachinePrecision] / N[(x + -1.0), $MachinePrecision]), $MachinePrecision] / N[(x * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{x + 1} + \frac{\frac{-1 + x \cdot 0.5}{x + -1}}{x \cdot -0.5}
\end{array}
Derivation
  1. Initial program 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. associate-+l-68.4%

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

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\left(\frac{2}{x} - \frac{1}{x - 1}\right)\right)} \]
    3. +-commutative68.4%

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

      \[\leadsto \frac{1}{1 + x} + \left(-\color{blue}{\left(\frac{2}{x} + \left(-\frac{1}{x - 1}\right)\right)}\right) \]
    5. distribute-neg-in68.4%

      \[\leadsto \frac{1}{1 + x} + \color{blue}{\left(\left(-\frac{2}{x}\right) + \left(-\left(-\frac{1}{x - 1}\right)\right)\right)} \]
    6. distribute-neg-frac68.4%

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

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

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

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

      \[\leadsto \frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. clear-num68.4%

      \[\leadsto \frac{1}{1 + x} + \left(\color{blue}{\frac{1}{\frac{x}{-2}}} + \frac{1}{x + -1}\right) \]
    2. frac-add18.4%

      \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{1 \cdot \left(x + -1\right) + \frac{x}{-2} \cdot 1}{\frac{x}{-2} \cdot \left(x + -1\right)}} \]
    3. *-un-lft-identity18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\color{blue}{\left(x + -1\right)} + \frac{x}{-2} \cdot 1}{\frac{x}{-2} \cdot \left(x + -1\right)} \]
    4. div-inv18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\left(x + -1\right) + \color{blue}{\left(x \cdot \frac{1}{-2}\right)} \cdot 1}{\frac{x}{-2} \cdot \left(x + -1\right)} \]
    5. metadata-eval18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\left(x + -1\right) + \left(x \cdot \color{blue}{-0.5}\right) \cdot 1}{\frac{x}{-2} \cdot \left(x + -1\right)} \]
    6. div-inv18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\left(x + -1\right) + \left(x \cdot -0.5\right) \cdot 1}{\color{blue}{\left(x \cdot \frac{1}{-2}\right)} \cdot \left(x + -1\right)} \]
    7. metadata-eval18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\left(x + -1\right) + \left(x \cdot -0.5\right) \cdot 1}{\left(x \cdot \color{blue}{-0.5}\right) \cdot \left(x + -1\right)} \]
  6. Applied egg-rr18.4%

    \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{\left(x + -1\right) + \left(x \cdot -0.5\right) \cdot 1}{\left(x \cdot -0.5\right) \cdot \left(x + -1\right)}} \]
  7. Step-by-step derivation
    1. *-rgt-identity18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\left(x + -1\right) + \color{blue}{x \cdot -0.5}}{\left(x \cdot -0.5\right) \cdot \left(x + -1\right)} \]
    2. +-commutative18.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\color{blue}{x \cdot -0.5 + \left(x + -1\right)}}{\left(x \cdot -0.5\right) \cdot \left(x + -1\right)} \]
    3. associate-/l/68.4%

      \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{\frac{x \cdot -0.5 + \left(x + -1\right)}{x + -1}}{x \cdot -0.5}} \]
    4. associate-+r+68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{\left(x \cdot -0.5 + x\right) + -1}}{x + -1}}{x \cdot -0.5} \]
    5. *-commutative68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\left(\color{blue}{-0.5 \cdot x} + x\right) + -1}{x + -1}}{x \cdot -0.5} \]
    6. distribute-lft1-in68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{\left(-0.5 + 1\right) \cdot x} + -1}{x + -1}}{x \cdot -0.5} \]
    7. metadata-eval68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{0.5} \cdot x + -1}{x + -1}}{x \cdot -0.5} \]
    8. metadata-eval68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{\left(-1 \cdot -0.5\right)} \cdot x + -1}{x + -1}}{x \cdot -0.5} \]
    9. associate-*r*68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{-1 \cdot \left(-0.5 \cdot x\right)} + -1}{x + -1}}{x \cdot -0.5} \]
    10. *-commutative68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{-1 \cdot \color{blue}{\left(x \cdot -0.5\right)} + -1}{x + -1}}{x \cdot -0.5} \]
    11. +-commutative68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{\color{blue}{-1 + -1 \cdot \left(x \cdot -0.5\right)}}{x + -1}}{x \cdot -0.5} \]
    12. *-commutative68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{-1 + \color{blue}{\left(x \cdot -0.5\right) \cdot -1}}{x + -1}}{x \cdot -0.5} \]
    13. associate-*l*68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{-1 + \color{blue}{x \cdot \left(-0.5 \cdot -1\right)}}{x + -1}}{x \cdot -0.5} \]
    14. metadata-eval68.4%

      \[\leadsto \frac{1}{1 + x} + \frac{\frac{-1 + x \cdot \color{blue}{0.5}}{x + -1}}{x \cdot -0.5} \]
  8. Simplified68.4%

    \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{\frac{-1 + x \cdot 0.5}{x + -1}}{x \cdot -0.5}} \]
  9. Final simplification68.4%

    \[\leadsto \frac{1}{x + 1} + \frac{\frac{-1 + x \cdot 0.5}{x + -1}}{x \cdot -0.5} \]
  10. Add Preprocessing

Alternative 5: 69.1% 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}
Derivation
  1. Initial program 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Add Preprocessing
  3. Final simplification68.4%

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

Alternative 6: 67.7% accurate, 1.2× speedup?

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

\\
\frac{-2}{x} + \left(\frac{1}{x} + \frac{-1}{1 - x}\right)
\end{array}
Derivation
  1. Initial program 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.4%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.4%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.4%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.4%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.4%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.4%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.4%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.4%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.4%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 66.7%

    \[\leadsto \frac{-2}{x} + \left(\color{blue}{\frac{1}{x}} + \frac{-1}{1 - x}\right) \]
  6. Final simplification66.7%

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

Alternative 7: 67.5% accurate, 2.1× speedup?

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

\\
\frac{-2}{x} + \frac{2}{x}
\end{array}
Derivation
  1. Initial program 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.4%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.4%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.4%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.4%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.4%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.4%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.4%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.4%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.4%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 66.5%

    \[\leadsto \frac{-2}{x} + \color{blue}{\frac{2}{x}} \]
  6. Final simplification66.5%

    \[\leadsto \frac{-2}{x} + \frac{2}{x} \]
  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 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.4%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.4%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.4%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.4%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.4%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.4%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.4%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.4%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.4%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
  3. Simplified68.4%

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

    \[\leadsto \color{blue}{\frac{-2}{x}} \]
  6. Final simplification4.9%

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

Alternative 9: 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 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. associate-+l-68.4%

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

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\left(\frac{2}{x} - \frac{1}{x - 1}\right)\right)} \]
    3. +-commutative68.4%

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

      \[\leadsto \frac{1}{1 + x} + \left(-\color{blue}{\left(\frac{2}{x} + \left(-\frac{1}{x - 1}\right)\right)}\right) \]
    5. distribute-neg-in68.4%

      \[\leadsto \frac{1}{1 + x} + \color{blue}{\left(\left(-\frac{2}{x}\right) + \left(-\left(-\frac{1}{x - 1}\right)\right)\right)} \]
    6. distribute-neg-frac68.4%

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

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

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

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

      \[\leadsto \frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 66.7%

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

    \[\leadsto \color{blue}{\frac{-1}{x}} \]
  7. Final simplification4.9%

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

Alternative 10: 3.4% accurate, 15.0× 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 68.4%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.4%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.4%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.4%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.4%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.4%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.4%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.4%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.4%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.4%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.4%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
  3. Simplified68.4%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{-1}{1 - x}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 3.4%

    \[\leadsto \frac{-2}{x} + \left(\color{blue}{1} + \frac{-1}{1 - x}\right) \]
  6. Taylor expanded in x around inf 3.4%

    \[\leadsto \color{blue}{1} \]
  7. Final simplification3.4%

    \[\leadsto 1 \]
  8. Add Preprocessing

Developer target: 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 2024010 
(FPCore (x)
  :name "3frac (problem 3.3.3)"
  :precision binary64
  :pre (> (fabs x) 1.0)

  :herbie-target
  (/ 2.0 (* x (- (* x x) 1.0)))

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