3frac (problem 3.3.3)

Percentage Accurate: 69.4% → 99.4%
Time: 11.8s
Alternatives: 6
Speedup: 0.1×

Specification

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

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

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 6 alternatives:

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

Initial Program: 69.4% 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: 99.4% accurate, 0.1× speedup?

\[\begin{array}{l} \\ 2 \cdot {x}^{-3} + \frac{2}{{x}^{5}} \end{array} \]
(FPCore (x) :precision binary64 (+ (* 2.0 (pow x -3.0)) (/ 2.0 (pow x 5.0))))
double code(double x) {
	return (2.0 * pow(x, -3.0)) + (2.0 / pow(x, 5.0));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (2.0d0 * (x ** (-3.0d0))) + (2.0d0 / (x ** 5.0d0))
end function
public static double code(double x) {
	return (2.0 * Math.pow(x, -3.0)) + (2.0 / Math.pow(x, 5.0));
}
def code(x):
	return (2.0 * math.pow(x, -3.0)) + (2.0 / math.pow(x, 5.0))
function code(x)
	return Float64(Float64(2.0 * (x ^ -3.0)) + Float64(2.0 / (x ^ 5.0)))
end
function tmp = code(x)
	tmp = (2.0 * (x ^ -3.0)) + (2.0 / (x ^ 5.0));
end
code[x_] := N[(N[(2.0 * N[Power[x, -3.0], $MachinePrecision]), $MachinePrecision] + N[(2.0 / N[Power[x, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
2 \cdot {x}^{-3} + \frac{2}{{x}^{5}}
\end{array}
Derivation
  1. Initial program 71.9%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
    3. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
    4. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    5. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
    7. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-171.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative71.9%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+71.8%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative71.8%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-171.8%

      \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    13. metadata-eval71.8%

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*71.8%

      \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    15. metadata-eval71.8%

      \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    16. metadata-eval71.8%

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
    20. metadata-eval71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified71.8%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 98.5%

    \[\leadsto \color{blue}{2 \cdot \frac{1}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{5}}} \]
  6. Step-by-step derivation
    1. associate-*r/98.5%

      \[\leadsto \color{blue}{\frac{2 \cdot 1}{{x}^{3}}} + 2 \cdot \frac{1}{{x}^{5}} \]
    2. metadata-eval98.5%

      \[\leadsto \frac{\color{blue}{2}}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{5}} \]
    3. associate-*r/98.5%

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

      \[\leadsto \frac{2}{{x}^{3}} + \frac{\color{blue}{2}}{{x}^{5}} \]
  7. Simplified98.5%

    \[\leadsto \color{blue}{\frac{2}{{x}^{3}} + \frac{2}{{x}^{5}}} \]
  8. Step-by-step derivation
    1. div-inv98.5%

      \[\leadsto \color{blue}{2 \cdot \frac{1}{{x}^{3}}} + \frac{2}{{x}^{5}} \]
    2. pow-flip99.1%

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

      \[\leadsto 2 \cdot {x}^{\color{blue}{-3}} + \frac{2}{{x}^{5}} \]
  9. Applied egg-rr99.1%

    \[\leadsto \color{blue}{2 \cdot {x}^{-3}} + \frac{2}{{x}^{5}} \]
  10. Final simplification99.1%

    \[\leadsto 2 \cdot {x}^{-3} + \frac{2}{{x}^{5}} \]
  11. Add Preprocessing

Alternative 2: 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 71.9%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
    3. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
    4. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    5. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
    7. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-171.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative71.9%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+71.8%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative71.8%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-171.8%

      \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    13. metadata-eval71.8%

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*71.8%

      \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    15. metadata-eval71.8%

      \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    16. metadata-eval71.8%

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
    20. metadata-eval71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified71.8%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 97.8%

    \[\leadsto \color{blue}{\frac{2}{{x}^{3}}} \]
  6. Step-by-step derivation
    1. div-inv98.5%

      \[\leadsto \color{blue}{2 \cdot \frac{1}{{x}^{3}}} + \frac{2}{{x}^{5}} \]
    2. pow-flip99.1%

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

      \[\leadsto 2 \cdot {x}^{\color{blue}{-3}} + \frac{2}{{x}^{5}} \]
  7. Applied egg-rr98.4%

    \[\leadsto \color{blue}{2 \cdot {x}^{-3}} \]
  8. Final simplification98.4%

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

Alternative 3: 44.8% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 5 \cdot 10^{+85}:\\ \;\;\;\;\frac{-2}{x} + x \cdot \frac{\frac{2}{x + 1}}{x + -1}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x} + \frac{2}{x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 5e+85)
   (+ (/ -2.0 x) (* x (/ (/ 2.0 (+ x 1.0)) (+ x -1.0))))
   (+ (/ -2.0 x) (/ 2.0 x))))
double code(double x) {
	double tmp;
	if (x <= 5e+85) {
		tmp = (-2.0 / x) + (x * ((2.0 / (x + 1.0)) / (x + -1.0)));
	} else {
		tmp = (-2.0 / x) + (2.0 / x);
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= 5d+85) then
        tmp = ((-2.0d0) / x) + (x * ((2.0d0 / (x + 1.0d0)) / (x + (-1.0d0))))
    else
        tmp = ((-2.0d0) / x) + (2.0d0 / x)
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= 5e+85) {
		tmp = (-2.0 / x) + (x * ((2.0 / (x + 1.0)) / (x + -1.0)));
	} else {
		tmp = (-2.0 / x) + (2.0 / x);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= 5e+85:
		tmp = (-2.0 / x) + (x * ((2.0 / (x + 1.0)) / (x + -1.0)))
	else:
		tmp = (-2.0 / x) + (2.0 / x)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= 5e+85)
		tmp = Float64(Float64(-2.0 / x) + Float64(x * Float64(Float64(2.0 / Float64(x + 1.0)) / Float64(x + -1.0))));
	else
		tmp = Float64(Float64(-2.0 / x) + Float64(2.0 / x));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= 5e+85)
		tmp = (-2.0 / x) + (x * ((2.0 / (x + 1.0)) / (x + -1.0)));
	else
		tmp = (-2.0 / x) + (2.0 / x);
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, 5e+85], N[(N[(-2.0 / x), $MachinePrecision] + N[(x * N[(N[(2.0 / N[(x + 1.0), $MachinePrecision]), $MachinePrecision] / N[(x + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-2.0 / x), $MachinePrecision] + N[(2.0 / x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 5 \cdot 10^{+85}:\\
\;\;\;\;\frac{-2}{x} + x \cdot \frac{\frac{2}{x + 1}}{x + -1}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 5.0000000000000001e85

    1. Initial program 57.6%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg57.6%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
      3. metadata-eval57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
      4. metadata-eval57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      5. metadata-eval57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
      7. metadata-eval57.6%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-157.6%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative57.6%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+57.5%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative57.5%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-157.5%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval57.5%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*57.5%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval57.5%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval57.5%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative57.5%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative57.5%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
      19. sub-neg57.5%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
      20. metadata-eval57.5%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
    3. Simplified57.5%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. frac-add19.6%

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

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

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

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

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

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

        \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{\color{blue}{1 \cdot 1}}{\left(1 + x\right) \cdot \left(x + -1\right)} \]
      8. frac-times15.8%

        \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \color{blue}{\left(\frac{1}{1 + x} \cdot \frac{1}{x + -1}\right)} \]
      9. clear-num15.8%

        \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \left(\frac{1}{1 + x} \cdot \color{blue}{\frac{1}{\frac{x + -1}{1}}}\right) \]
      10. frac-times18.4%

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

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

        \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\color{blue}{\left(x + 1\right)} \cdot \frac{x + -1}{1}} \]
      13. /-rgt-identity18.4%

        \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\left(x + 1\right) \cdot \color{blue}{\left(x + -1\right)}} \]
    6. Applied egg-rr18.4%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    7. Step-by-step derivation
      1. associate-*r/19.6%

        \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot 1}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
      2. *-rgt-identity19.6%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(x + 1\right) + \left(x + -1\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      3. associate-+l+19.6%

        \[\leadsto \frac{-2}{x} + \frac{\color{blue}{x + \left(1 + \left(x + -1\right)\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      4. +-commutative19.6%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(1 + \color{blue}{\left(-1 + x\right)}\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      5. associate-+r+19.6%

        \[\leadsto \frac{-2}{x} + \frac{x + \color{blue}{\left(\left(1 + -1\right) + x\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      6. metadata-eval19.6%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(\color{blue}{0} + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
      7. *-commutative19.6%

        \[\leadsto \frac{-2}{x} + \frac{x + \left(0 + x\right)}{\color{blue}{\left(x + -1\right) \cdot \left(x + 1\right)}} \]
    8. Simplified19.6%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + -1\right) \cdot \left(x + 1\right)}} \]
    9. Applied egg-rr54.2%

      \[\leadsto \color{blue}{\frac{\left(\left(x + x\right) \cdot \frac{1}{x + 1}\right) \cdot x + \left(x + -1\right) \cdot -2}{\left(x + -1\right) \cdot x}} \]
    10. Step-by-step derivation
      1. frac-add57.4%

        \[\leadsto \color{blue}{\frac{\left(x + x\right) \cdot \frac{1}{x + 1}}{x + -1} + \frac{-2}{x}} \]
      2. *-commutative57.4%

        \[\leadsto \frac{\color{blue}{\frac{1}{x + 1} \cdot \left(x + x\right)}}{x + -1} + \frac{-2}{x} \]
      3. associate-*l/20.3%

        \[\leadsto \color{blue}{\frac{\frac{1}{x + 1}}{x + -1} \cdot \left(x + x\right)} + \frac{-2}{x} \]
      4. fma-def9.1%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + x, \frac{-2}{x}\right)} \]
      5. add-exp-log2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + \color{blue}{e^{\log x}}, \frac{-2}{x}\right) \]
      6. log1p-expm1-u2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\color{blue}{\mathsf{log1p}\left(\mathsf{expm1}\left(\log x\right)\right)}}, \frac{-2}{x}\right) \]
      7. expm1-def2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{e^{\log x} - 1}\right)}, \frac{-2}{x}\right) \]
      8. add-exp-log2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{x} - 1\right)}, \frac{-2}{x}\right) \]
      9. *-un-lft-identity2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{1 \cdot x} - 1\right)}, \frac{-2}{x}\right) \]
      10. fma-neg2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(1, x, -1\right)}\right)}, \frac{-2}{x}\right) \]
      11. metadata-eval2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\mathsf{fma}\left(1, x, \color{blue}{-1}\right)\right)}, \frac{-2}{x}\right) \]
      12. fma-def2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{1 \cdot x + -1}\right)}, \frac{-2}{x}\right) \]
      13. *-un-lft-identity2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{x} + -1\right)}, \frac{-2}{x}\right) \]
      14. log1p-udef2.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\color{blue}{\log \left(1 + \left(x + -1\right)\right)}}, \frac{-2}{x}\right) \]
      15. add-exp-log9.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + \color{blue}{\left(1 + \left(x + -1\right)\right)}, \frac{-2}{x}\right) \]
      16. associate-+l+9.1%

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, \color{blue}{\left(x + 1\right) + \left(x + -1\right)}, \frac{-2}{x}\right) \]
      17. fma-def20.3%

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

      \[\leadsto \color{blue}{\frac{2 \cdot x}{\left(x + 1\right) \cdot \left(x + -1\right)} + \frac{-2}{x}} \]
    12. Step-by-step derivation
      1. associate-/r*57.5%

        \[\leadsto \color{blue}{\frac{\frac{2 \cdot x}{x + 1}}{x + -1}} + \frac{-2}{x} \]
      2. div-inv57.5%

        \[\leadsto \color{blue}{\frac{2 \cdot x}{x + 1} \cdot \frac{1}{x + -1}} + \frac{-2}{x} \]
      3. *-un-lft-identity57.5%

        \[\leadsto \frac{2 \cdot x}{\color{blue}{1 \cdot \left(x + 1\right)}} \cdot \frac{1}{x + -1} + \frac{-2}{x} \]
      4. times-frac57.5%

        \[\leadsto \color{blue}{\left(\frac{2}{1} \cdot \frac{x}{x + 1}\right)} \cdot \frac{1}{x + -1} + \frac{-2}{x} \]
      5. metadata-eval57.5%

        \[\leadsto \left(\color{blue}{2} \cdot \frac{x}{x + 1}\right) \cdot \frac{1}{x + -1} + \frac{-2}{x} \]
    13. Applied egg-rr57.5%

      \[\leadsto \color{blue}{\left(2 \cdot \frac{x}{x + 1}\right) \cdot \frac{1}{x + -1}} + \frac{-2}{x} \]
    14. Step-by-step derivation
      1. associate-*r/57.5%

        \[\leadsto \color{blue}{\frac{\left(2 \cdot \frac{x}{x + 1}\right) \cdot 1}{x + -1}} + \frac{-2}{x} \]
      2. *-rgt-identity57.5%

        \[\leadsto \frac{\color{blue}{2 \cdot \frac{x}{x + 1}}}{x + -1} + \frac{-2}{x} \]
      3. associate-*r/57.5%

        \[\leadsto \frac{\color{blue}{\frac{2 \cdot x}{x + 1}}}{x + -1} + \frac{-2}{x} \]
      4. *-commutative57.5%

        \[\leadsto \frac{\frac{\color{blue}{x \cdot 2}}{x + 1}}{x + -1} + \frac{-2}{x} \]
      5. associate-*r/57.4%

        \[\leadsto \frac{\color{blue}{x \cdot \frac{2}{x + 1}}}{x + -1} + \frac{-2}{x} \]
      6. *-lft-identity57.4%

        \[\leadsto \frac{x \cdot \frac{2}{x + 1}}{\color{blue}{1 \cdot \left(x + -1\right)}} + \frac{-2}{x} \]
      7. times-frac20.3%

        \[\leadsto \color{blue}{\frac{x}{1} \cdot \frac{\frac{2}{x + 1}}{x + -1}} + \frac{-2}{x} \]
      8. /-rgt-identity20.3%

        \[\leadsto \color{blue}{x} \cdot \frac{\frac{2}{x + 1}}{x + -1} + \frac{-2}{x} \]
    15. Simplified20.3%

      \[\leadsto \color{blue}{x \cdot \frac{\frac{2}{x + 1}}{x + -1}} + \frac{-2}{x} \]

    if 5.0000000000000001e85 < x

    1. Initial program 94.9%

      \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
    2. Step-by-step derivation
      1. sub-neg94.9%

        \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
      2. distribute-neg-frac94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
      3. metadata-eval94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
      4. metadata-eval94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      5. metadata-eval94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
      6. associate-/r*94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
      7. metadata-eval94.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
      8. neg-mul-194.9%

        \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
      9. +-commutative94.9%

        \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
      10. associate-+l+94.9%

        \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      11. +-commutative94.9%

        \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
      12. neg-mul-194.9%

        \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      13. metadata-eval94.9%

        \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      14. associate-/r*94.9%

        \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      15. metadata-eval94.9%

        \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      16. metadata-eval94.9%

        \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
      17. +-commutative94.9%

        \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
      18. +-commutative94.9%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
      19. sub-neg94.9%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
      20. metadata-eval94.9%

        \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
    3. Simplified94.9%

      \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 94.9%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{2}{x}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification48.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 5 \cdot 10^{+85}:\\ \;\;\;\;\frac{-2}{x} + x \cdot \frac{\frac{2}{x + 1}}{x + -1}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2}{x} + \frac{2}{x}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 69.3% accurate, 1.0× speedup?

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

\\
\frac{x}{x + 1} \cdot \frac{2}{x + -1} + \frac{-2}{x}
\end{array}
Derivation
  1. Initial program 71.9%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
    3. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
    4. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    5. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
    7. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-171.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative71.9%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+71.8%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative71.8%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-171.8%

      \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    13. metadata-eval71.8%

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*71.8%

      \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    15. metadata-eval71.8%

      \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    16. metadata-eval71.8%

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
    20. metadata-eval71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified71.8%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-add19.3%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(x + -1\right)}} \]
    2. div-inv17.5%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1\right) \cdot \frac{1}{\left(1 + x\right) \cdot \left(x + -1\right)}} \]
    3. *-un-lft-identity17.5%

      \[\leadsto \frac{-2}{x} + \left(\color{blue}{\left(x + -1\right)} + \left(1 + x\right) \cdot 1\right) \cdot \frac{1}{\left(1 + x\right) \cdot \left(x + -1\right)} \]
    4. *-rgt-identity17.5%

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

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

      \[\leadsto \frac{-2}{x} + \left(\color{blue}{\left(x + 1\right)} + \left(x + -1\right)\right) \cdot \frac{1}{\left(1 + x\right) \cdot \left(x + -1\right)} \]
    7. metadata-eval17.5%

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{\color{blue}{1 \cdot 1}}{\left(1 + x\right) \cdot \left(x + -1\right)} \]
    8. frac-times16.7%

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \color{blue}{\left(\frac{1}{1 + x} \cdot \frac{1}{x + -1}\right)} \]
    9. clear-num16.7%

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \left(\frac{1}{1 + x} \cdot \color{blue}{\frac{1}{\frac{x + -1}{1}}}\right) \]
    10. frac-times17.5%

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \color{blue}{\frac{1 \cdot 1}{\left(1 + x\right) \cdot \frac{x + -1}{1}}} \]
    11. metadata-eval17.5%

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

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\color{blue}{\left(x + 1\right)} \cdot \frac{x + -1}{1}} \]
    13. /-rgt-identity17.5%

      \[\leadsto \frac{-2}{x} + \left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\left(x + 1\right) \cdot \color{blue}{\left(x + -1\right)}} \]
  6. Applied egg-rr17.5%

    \[\leadsto \frac{-2}{x} + \color{blue}{\left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot \frac{1}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
  7. Step-by-step derivation
    1. associate-*r/19.3%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{\left(\left(x + 1\right) + \left(x + -1\right)\right) \cdot 1}{\left(x + 1\right) \cdot \left(x + -1\right)}} \]
    2. *-rgt-identity19.3%

      \[\leadsto \frac{-2}{x} + \frac{\color{blue}{\left(x + 1\right) + \left(x + -1\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    3. associate-+l+19.3%

      \[\leadsto \frac{-2}{x} + \frac{\color{blue}{x + \left(1 + \left(x + -1\right)\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    4. +-commutative19.3%

      \[\leadsto \frac{-2}{x} + \frac{x + \left(1 + \color{blue}{\left(-1 + x\right)}\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    5. associate-+r+19.3%

      \[\leadsto \frac{-2}{x} + \frac{x + \color{blue}{\left(\left(1 + -1\right) + x\right)}}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    6. metadata-eval19.3%

      \[\leadsto \frac{-2}{x} + \frac{x + \left(\color{blue}{0} + x\right)}{\left(x + 1\right) \cdot \left(x + -1\right)} \]
    7. *-commutative19.3%

      \[\leadsto \frac{-2}{x} + \frac{x + \left(0 + x\right)}{\color{blue}{\left(x + -1\right) \cdot \left(x + 1\right)}} \]
  8. Simplified19.3%

    \[\leadsto \frac{-2}{x} + \color{blue}{\frac{x + \left(0 + x\right)}{\left(x + -1\right) \cdot \left(x + 1\right)}} \]
  9. Applied egg-rr68.3%

    \[\leadsto \color{blue}{\frac{\left(\left(x + x\right) \cdot \frac{1}{x + 1}\right) \cdot x + \left(x + -1\right) \cdot -2}{\left(x + -1\right) \cdot x}} \]
  10. Step-by-step derivation
    1. frac-add71.8%

      \[\leadsto \color{blue}{\frac{\left(x + x\right) \cdot \frac{1}{x + 1}}{x + -1} + \frac{-2}{x}} \]
    2. *-commutative71.8%

      \[\leadsto \frac{\color{blue}{\frac{1}{x + 1} \cdot \left(x + x\right)}}{x + -1} + \frac{-2}{x} \]
    3. associate-*l/21.3%

      \[\leadsto \color{blue}{\frac{\frac{1}{x + 1}}{x + -1} \cdot \left(x + x\right)} + \frac{-2}{x} \]
    4. fma-def8.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + x, \frac{-2}{x}\right)} \]
    5. add-exp-log3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + \color{blue}{e^{\log x}}, \frac{-2}{x}\right) \]
    6. log1p-expm1-u3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\color{blue}{\mathsf{log1p}\left(\mathsf{expm1}\left(\log x\right)\right)}}, \frac{-2}{x}\right) \]
    7. expm1-def3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{e^{\log x} - 1}\right)}, \frac{-2}{x}\right) \]
    8. add-exp-log3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{x} - 1\right)}, \frac{-2}{x}\right) \]
    9. *-un-lft-identity3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{1 \cdot x} - 1\right)}, \frac{-2}{x}\right) \]
    10. fma-neg3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{\mathsf{fma}\left(1, x, -1\right)}\right)}, \frac{-2}{x}\right) \]
    11. metadata-eval3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\mathsf{fma}\left(1, x, \color{blue}{-1}\right)\right)}, \frac{-2}{x}\right) \]
    12. fma-def3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{1 \cdot x + -1}\right)}, \frac{-2}{x}\right) \]
    13. *-un-lft-identity3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\mathsf{log1p}\left(\color{blue}{x} + -1\right)}, \frac{-2}{x}\right) \]
    14. log1p-udef3.7%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + e^{\color{blue}{\log \left(1 + \left(x + -1\right)\right)}}, \frac{-2}{x}\right) \]
    15. add-exp-log8.0%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, x + \color{blue}{\left(1 + \left(x + -1\right)\right)}, \frac{-2}{x}\right) \]
    16. associate-+l+8.0%

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{x + 1}}{x + -1}, \color{blue}{\left(x + 1\right) + \left(x + -1\right)}, \frac{-2}{x}\right) \]
    17. fma-def21.3%

      \[\leadsto \color{blue}{\frac{\frac{1}{x + 1}}{x + -1} \cdot \left(\left(x + 1\right) + \left(x + -1\right)\right) + \frac{-2}{x}} \]
  11. Applied egg-rr19.3%

    \[\leadsto \color{blue}{\frac{2 \cdot x}{\left(x + 1\right) \cdot \left(x + -1\right)} + \frac{-2}{x}} \]
  12. Step-by-step derivation
    1. *-commutative19.3%

      \[\leadsto \frac{\color{blue}{x \cdot 2}}{\left(x + 1\right) \cdot \left(x + -1\right)} + \frac{-2}{x} \]
    2. times-frac71.8%

      \[\leadsto \color{blue}{\frac{x}{x + 1} \cdot \frac{2}{x + -1}} + \frac{-2}{x} \]
  13. Applied egg-rr71.8%

    \[\leadsto \color{blue}{\frac{x}{x + 1} \cdot \frac{2}{x + -1}} + \frac{-2}{x} \]
  14. Final simplification71.8%

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

Alternative 5: 67.8% 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 71.9%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
    3. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
    4. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    5. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
    7. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-171.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative71.9%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+71.8%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative71.8%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-171.8%

      \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    13. metadata-eval71.8%

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*71.8%

      \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    15. metadata-eval71.8%

      \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    16. metadata-eval71.8%

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
    20. metadata-eval71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified71.8%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 69.5%

    \[\leadsto \frac{-2}{x} + \color{blue}{\frac{2}{x}} \]
  6. Final simplification69.5%

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

Alternative 6: 5.1% accurate, 5.0× speedup?

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

\\
\frac{-2}{x}
\end{array}
Derivation
  1. Initial program 71.9%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{-2}{x}}\right) + \frac{1}{x - 1} \]
    3. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{-2}}{x}\right) + \frac{1}{x - 1} \]
    4. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\color{blue}{\frac{2}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    5. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \color{blue}{\frac{2}{\left(-1\right) \cdot x}}\right) + \frac{1}{x - 1} \]
    7. metadata-eval71.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-171.9%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative71.9%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+71.8%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative71.8%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-171.8%

      \[\leadsto \frac{2}{\color{blue}{-1 \cdot x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    13. metadata-eval71.8%

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*71.8%

      \[\leadsto \color{blue}{\frac{\frac{2}{-1}}{x}} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    15. metadata-eval71.8%

      \[\leadsto \frac{\frac{2}{\color{blue}{-1}}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    16. metadata-eval71.8%

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{\color{blue}{x + \left(-1\right)}}\right) \]
    20. metadata-eval71.8%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified71.8%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 5.0%

    \[\leadsto \color{blue}{\frac{-2}{x}} \]
  6. Final simplification5.0%

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

Developer target: 99.1% 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 2024039 
(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))))