3frac (problem 3.3.3)

Percentage Accurate: 68.5% → 99.7%
Time: 12.5s
Alternatives: 8
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 8 alternatives:

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

Initial Program: 68.5% accurate, 1.0× speedup?

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

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

Alternative 1: 99.7% accurate, 0.0× speedup?

\[\begin{array}{l} \\ \frac{2}{{x}^{5}} + \left(2 \cdot {x}^{-3} + \frac{2}{{x}^{7}}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (+ (/ 2.0 (pow x 5.0)) (+ (* 2.0 (pow x -3.0)) (/ 2.0 (pow x 7.0)))))
double code(double x) {
	return (2.0 / pow(x, 5.0)) + ((2.0 * pow(x, -3.0)) + (2.0 / pow(x, 7.0)));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = (2.0d0 / (x ** 5.0d0)) + ((2.0d0 * (x ** (-3.0d0))) + (2.0d0 / (x ** 7.0d0)))
end function
public static double code(double x) {
	return (2.0 / Math.pow(x, 5.0)) + ((2.0 * Math.pow(x, -3.0)) + (2.0 / Math.pow(x, 7.0)));
}
def code(x):
	return (2.0 / math.pow(x, 5.0)) + ((2.0 * math.pow(x, -3.0)) + (2.0 / math.pow(x, 7.0)))
function code(x)
	return Float64(Float64(2.0 / (x ^ 5.0)) + Float64(Float64(2.0 * (x ^ -3.0)) + Float64(2.0 / (x ^ 7.0))))
end
function tmp = code(x)
	tmp = (2.0 / (x ^ 5.0)) + ((2.0 * (x ^ -3.0)) + (2.0 / (x ^ 7.0)));
end
code[x_] := N[(N[(2.0 / N[Power[x, 5.0], $MachinePrecision]), $MachinePrecision] + N[(N[(2.0 * N[Power[x, -3.0], $MachinePrecision]), $MachinePrecision] + N[(2.0 / N[Power[x, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{2}{{x}^{5}} + \left(2 \cdot {x}^{-3} + \frac{2}{{x}^{7}}\right)
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 99.1%

    \[\leadsto \color{blue}{2 \cdot \frac{1}{{x}^{5}} + \left(2 \cdot \frac{1}{{x}^{7}} + 2 \cdot \frac{1}{{x}^{3}}\right)} \]
  6. Step-by-step derivation
    1. associate-*r/99.1%

      \[\leadsto \color{blue}{\frac{2 \cdot 1}{{x}^{5}}} + \left(2 \cdot \frac{1}{{x}^{7}} + 2 \cdot \frac{1}{{x}^{3}}\right) \]
    2. metadata-eval99.1%

      \[\leadsto \frac{\color{blue}{2}}{{x}^{5}} + \left(2 \cdot \frac{1}{{x}^{7}} + 2 \cdot \frac{1}{{x}^{3}}\right) \]
    3. +-commutative99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \color{blue}{\left(2 \cdot \frac{1}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{7}}\right)} \]
    4. associate-*r/99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\frac{2 \cdot 1}{{x}^{3}}} + 2 \cdot \frac{1}{{x}^{7}}\right) \]
    5. metadata-eval99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\frac{\color{blue}{2}}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{7}}\right) \]
    6. associate-*r/99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\frac{2}{{x}^{3}} + \color{blue}{\frac{2 \cdot 1}{{x}^{7}}}\right) \]
    7. metadata-eval99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\frac{2}{{x}^{3}} + \frac{\color{blue}{2}}{{x}^{7}}\right) \]
  7. Simplified99.1%

    \[\leadsto \color{blue}{\frac{2}{{x}^{5}} + \left(\frac{2}{{x}^{3}} + \frac{2}{{x}^{7}}\right)} \]
  8. Step-by-step derivation
    1. expm1-log1p-u99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)\right)} + \frac{2}{{x}^{7}}\right) \]
    2. expm1-udef67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)} - 1\right)} + \frac{2}{{x}^{7}}\right) \]
    3. div-inv67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(\color{blue}{2 \cdot \frac{1}{{x}^{3}}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
    4. pow-flip67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(2 \cdot \color{blue}{{x}^{\left(-3\right)}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
    5. metadata-eval67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(2 \cdot {x}^{\color{blue}{-3}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
  9. Applied egg-rr67.9%

    \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\left(e^{\mathsf{log1p}\left(2 \cdot {x}^{-3}\right)} - 1\right)} + \frac{2}{{x}^{7}}\right) \]
  10. Step-by-step derivation
    1. expm1-def99.5%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(2 \cdot {x}^{-3}\right)\right)} + \frac{2}{{x}^{7}}\right) \]
    2. expm1-log1p99.5%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{2 \cdot {x}^{-3}} + \frac{2}{{x}^{7}}\right) \]
  11. Simplified99.5%

    \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{2 \cdot {x}^{-3}} + \frac{2}{{x}^{7}}\right) \]
  12. Final simplification99.5%

    \[\leadsto \frac{2}{{x}^{5}} + \left(2 \cdot {x}^{-3} + \frac{2}{{x}^{7}}\right) \]
  13. Add Preprocessing

Alternative 2: 98.7% accurate, 0.1× speedup?

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

\\
\frac{2}{{x}^{5}} + \frac{2}{{x}^{3}}
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 98.9%

    \[\leadsto \color{blue}{2 \cdot \frac{1}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{5}}} \]
  6. Step-by-step derivation
    1. associate-*r/98.9%

      \[\leadsto \color{blue}{\frac{2 \cdot 1}{{x}^{3}}} + 2 \cdot \frac{1}{{x}^{5}} \]
    2. metadata-eval98.9%

      \[\leadsto \frac{\color{blue}{2}}{{x}^{3}} + 2 \cdot \frac{1}{{x}^{5}} \]
    3. associate-*r/98.9%

      \[\leadsto \frac{2}{{x}^{3}} + \color{blue}{\frac{2 \cdot 1}{{x}^{5}}} \]
    4. metadata-eval98.9%

      \[\leadsto \frac{2}{{x}^{3}} + \frac{\color{blue}{2}}{{x}^{5}} \]
  7. Simplified98.9%

    \[\leadsto \color{blue}{\frac{2}{{x}^{3}} + \frac{2}{{x}^{5}}} \]
  8. Final simplification98.9%

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

Alternative 3: 99.0% accurate, 0.1× speedup?

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

\\
2 \cdot {x}^{-3}
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

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

    \[\leadsto \color{blue}{\frac{2}{{x}^{3}}} \]
  6. Step-by-step derivation
    1. expm1-log1p-u99.1%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)\right)} + \frac{2}{{x}^{7}}\right) \]
    2. expm1-udef67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{2}{{x}^{3}}\right)} - 1\right)} + \frac{2}{{x}^{7}}\right) \]
    3. div-inv67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(\color{blue}{2 \cdot \frac{1}{{x}^{3}}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
    4. pow-flip67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(2 \cdot \color{blue}{{x}^{\left(-3\right)}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
    5. metadata-eval67.9%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\left(e^{\mathsf{log1p}\left(2 \cdot {x}^{\color{blue}{-3}}\right)} - 1\right) + \frac{2}{{x}^{7}}\right) \]
  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-def99.5%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(2 \cdot {x}^{-3}\right)\right)} + \frac{2}{{x}^{7}}\right) \]
    2. expm1-log1p99.5%

      \[\leadsto \frac{2}{{x}^{5}} + \left(\color{blue}{2 \cdot {x}^{-3}} + \frac{2}{{x}^{7}}\right) \]
  9. Simplified98.8%

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

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

Alternative 4: 68.4% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot 0.5 - \frac{0.5}{x}\\ \frac{x + t\_0 \cdot -2}{x \cdot t\_0} \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (- (* x 0.5) (/ 0.5 x)))) (/ (+ x (* t_0 -2.0)) (* x t_0))))
double code(double x) {
	double t_0 = (x * 0.5) - (0.5 / x);
	return (x + (t_0 * -2.0)) / (x * t_0);
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    t_0 = (x * 0.5d0) - (0.5d0 / x)
    code = (x + (t_0 * (-2.0d0))) / (x * t_0)
end function
public static double code(double x) {
	double t_0 = (x * 0.5) - (0.5 / x);
	return (x + (t_0 * -2.0)) / (x * t_0);
}
def code(x):
	t_0 = (x * 0.5) - (0.5 / x)
	return (x + (t_0 * -2.0)) / (x * t_0)
function code(x)
	t_0 = Float64(Float64(x * 0.5) - Float64(0.5 / x))
	return Float64(Float64(x + Float64(t_0 * -2.0)) / Float64(x * t_0))
end
function tmp = code(x)
	t_0 = (x * 0.5) - (0.5 / x);
	tmp = (x + (t_0 * -2.0)) / (x * t_0);
end
code[x_] := Block[{t$95$0 = N[(N[(x * 0.5), $MachinePrecision] - N[(0.5 / x), $MachinePrecision]), $MachinePrecision]}, N[(N[(x + N[(t$95$0 * -2.0), $MachinePrecision]), $MachinePrecision] / N[(x * t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot 0.5 - \frac{0.5}{x}\\
\frac{x + t\_0 \cdot -2}{x \cdot t\_0}
\end{array}
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-add18.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(x + -1\right)}} \]
    2. clear-num20.7%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1}{\frac{\left(1 + x\right) \cdot \left(x + -1\right)}{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}}} \]
    3. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\color{blue}{\left(x + 1\right)} \cdot \left(x + -1\right)}{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}} \]
    4. *-un-lft-identity20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(x + -1\right)} + \left(1 + x\right) \cdot 1}} \]
    5. *-rgt-identity20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\left(x + -1\right) + \color{blue}{\left(1 + x\right)}}} \]
    6. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(1 + x\right) + \left(x + -1\right)}}} \]
    7. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(x + 1\right)} + \left(x + -1\right)}} \]
  6. Applied egg-rr20.7%

    \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\left(x + 1\right) + \left(x + -1\right)}}} \]
  7. Taylor expanded in x around 0 68.0%

    \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{0.5 \cdot x - 0.5 \cdot \frac{1}{x}}} \]
  8. Step-by-step derivation
    1. *-commutative68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{x \cdot 0.5} - 0.5 \cdot \frac{1}{x}} \]
    2. associate-*r/68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \color{blue}{\frac{0.5 \cdot 1}{x}}} \]
    3. metadata-eval68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \frac{\color{blue}{0.5}}{x}} \]
  9. Simplified68.0%

    \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{x \cdot 0.5 - \frac{0.5}{x}}} \]
  10. Step-by-step derivation
    1. +-commutative68.0%

      \[\leadsto \color{blue}{\frac{1}{x \cdot 0.5 - \frac{0.5}{x}} + \frac{-2}{x}} \]
    2. frac-add68.1%

      \[\leadsto \color{blue}{\frac{1 \cdot x + \left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot -2}{\left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot x}} \]
    3. *-un-lft-identity68.1%

      \[\leadsto \frac{\color{blue}{x} + \left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot -2}{\left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot x} \]
  11. Applied egg-rr68.1%

    \[\leadsto \color{blue}{\frac{x + \left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot -2}{\left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot x}} \]
  12. Final simplification68.1%

    \[\leadsto \frac{x + \left(x \cdot 0.5 - \frac{0.5}{x}\right) \cdot -2}{x \cdot \left(x \cdot 0.5 - \frac{0.5}{x}\right)} \]
  13. Add Preprocessing

Alternative 5: 68.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \frac{0.5}{x}} \end{array} \]
(FPCore (x) :precision binary64 (+ (/ -2.0 x) (/ 1.0 (- (* x 0.5) (/ 0.5 x)))))
double code(double x) {
	return (-2.0 / x) + (1.0 / ((x * 0.5) - (0.5 / x)));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = ((-2.0d0) / x) + (1.0d0 / ((x * 0.5d0) - (0.5d0 / x)))
end function
public static double code(double x) {
	return (-2.0 / x) + (1.0 / ((x * 0.5) - (0.5 / x)));
}
def code(x):
	return (-2.0 / x) + (1.0 / ((x * 0.5) - (0.5 / x)))
function code(x)
	return Float64(Float64(-2.0 / x) + Float64(1.0 / Float64(Float64(x * 0.5) - Float64(0.5 / x))))
end
function tmp = code(x)
	tmp = (-2.0 / x) + (1.0 / ((x * 0.5) - (0.5 / x)));
end
code[x_] := N[(N[(-2.0 / x), $MachinePrecision] + N[(1.0 / N[(N[(x * 0.5), $MachinePrecision] - N[(0.5 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2}{x} + \frac{1}{x \cdot 0.5 - \frac{0.5}{x}}
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-add18.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}{\left(1 + x\right) \cdot \left(x + -1\right)}} \]
    2. clear-num20.7%

      \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1}{\frac{\left(1 + x\right) \cdot \left(x + -1\right)}{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}}} \]
    3. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\color{blue}{\left(x + 1\right)} \cdot \left(x + -1\right)}{1 \cdot \left(x + -1\right) + \left(1 + x\right) \cdot 1}} \]
    4. *-un-lft-identity20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(x + -1\right)} + \left(1 + x\right) \cdot 1}} \]
    5. *-rgt-identity20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\left(x + -1\right) + \color{blue}{\left(1 + x\right)}}} \]
    6. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(1 + x\right) + \left(x + -1\right)}}} \]
    7. +-commutative20.7%

      \[\leadsto \frac{-2}{x} + \frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\color{blue}{\left(x + 1\right)} + \left(x + -1\right)}} \]
  6. Applied egg-rr20.7%

    \[\leadsto \frac{-2}{x} + \color{blue}{\frac{1}{\frac{\left(x + 1\right) \cdot \left(x + -1\right)}{\left(x + 1\right) + \left(x + -1\right)}}} \]
  7. Taylor expanded in x around 0 68.0%

    \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{0.5 \cdot x - 0.5 \cdot \frac{1}{x}}} \]
  8. Step-by-step derivation
    1. *-commutative68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{x \cdot 0.5} - 0.5 \cdot \frac{1}{x}} \]
    2. associate-*r/68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \color{blue}{\frac{0.5 \cdot 1}{x}}} \]
    3. metadata-eval68.0%

      \[\leadsto \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \frac{\color{blue}{0.5}}{x}} \]
  9. Simplified68.0%

    \[\leadsto \frac{-2}{x} + \frac{1}{\color{blue}{x \cdot 0.5 - \frac{0.5}{x}}} \]
  10. Final simplification68.0%

    \[\leadsto \frac{-2}{x} + \frac{1}{x \cdot 0.5 - \frac{0.5}{x}} \]
  11. Add Preprocessing

Alternative 6: 67.0% 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 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 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 7: 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 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. sub-neg68.0%

      \[\leadsto \color{blue}{\left(\frac{1}{x + 1} + \left(-\frac{2}{x}\right)\right)} + \frac{1}{x - 1} \]
    2. distribute-neg-frac68.0%

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

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

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{\frac{2}{\color{blue}{-1}}}{x}\right) + \frac{1}{x - 1} \]
    6. associate-/r*68.0%

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

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-1} \cdot x}\right) + \frac{1}{x - 1} \]
    8. neg-mul-168.0%

      \[\leadsto \left(\frac{1}{x + 1} + \frac{2}{\color{blue}{-x}}\right) + \frac{1}{x - 1} \]
    9. +-commutative68.0%

      \[\leadsto \color{blue}{\left(\frac{2}{-x} + \frac{1}{x + 1}\right)} + \frac{1}{x - 1} \]
    10. associate-+l+68.0%

      \[\leadsto \color{blue}{\frac{2}{-x} + \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    11. +-commutative68.0%

      \[\leadsto \frac{2}{-x} + \color{blue}{\left(\frac{1}{x - 1} + \frac{1}{x + 1}\right)} \]
    12. neg-mul-168.0%

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

      \[\leadsto \frac{2}{\color{blue}{\left(-1\right)} \cdot x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    14. associate-/r*68.0%

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

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

      \[\leadsto \frac{\color{blue}{-2}}{x} + \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) \]
    17. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \color{blue}{\left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)} \]
    18. +-commutative68.0%

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{\color{blue}{1 + x}} + \frac{1}{x - 1}\right) \]
    19. sub-neg68.0%

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

      \[\leadsto \frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{-2}{x} + \left(\frac{1}{1 + x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around 0 5.1%

    \[\leadsto \color{blue}{\frac{-2}{x}} \]
  6. Final simplification5.1%

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

Alternative 8: 3.4% accurate, 15.0× speedup?

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

\\
2
\end{array}
Derivation
  1. Initial program 68.0%

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1} \]
  2. Step-by-step derivation
    1. associate-+l-68.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} - \left(\frac{2}{x} - \frac{1}{x - 1}\right)} \]
    2. sub-neg68.0%

      \[\leadsto \color{blue}{\frac{1}{x + 1} + \left(-\left(\frac{2}{x} - \frac{1}{x - 1}\right)\right)} \]
    3. +-commutative68.0%

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

      \[\leadsto \frac{1}{1 + x} + \color{blue}{\left(0 - \left(\frac{2}{x} - \frac{1}{x - 1}\right)\right)} \]
    5. associate-+l-68.0%

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

      \[\leadsto \frac{1}{1 + x} + \left(\color{blue}{\left(-\frac{2}{x}\right)} + \frac{1}{x - 1}\right) \]
    7. distribute-neg-frac68.0%

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

      \[\leadsto \frac{1}{1 + x} + \left(\frac{\color{blue}{-2}}{x} + \frac{1}{x - 1}\right) \]
    9. sub-neg68.0%

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

      \[\leadsto \frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + \color{blue}{-1}}\right) \]
  3. Simplified68.0%

    \[\leadsto \color{blue}{\frac{1}{1 + x} + \left(\frac{-2}{x} + \frac{1}{x + -1}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. frac-2neg68.0%

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

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

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

      \[\leadsto \frac{1}{1 + x} + \frac{-2 \cdot \left(-\color{blue}{\left(-1 + x\right)}\right) + x \cdot -1}{x \cdot \left(-\left(x + -1\right)\right)} \]
    5. distribute-neg-in18.1%

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

      \[\leadsto \frac{1}{1 + x} + \frac{-2 \cdot \left(\color{blue}{1} + \left(-x\right)\right) + x \cdot -1}{x \cdot \left(-\left(x + -1\right)\right)} \]
    7. sub-neg18.1%

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

      \[\leadsto \frac{1}{1 + x} + \frac{-2 \cdot \left(1 - x\right) + \color{blue}{-1 \cdot x}}{x \cdot \left(-\left(x + -1\right)\right)} \]
    9. neg-mul-118.1%

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

      \[\leadsto \frac{1}{1 + x} + \frac{-2 \cdot \left(1 - x\right) + \left(-x\right)}{x \cdot \left(-\color{blue}{\left(-1 + x\right)}\right)} \]
    11. distribute-neg-in18.1%

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

      \[\leadsto \frac{1}{1 + x} + \frac{-2 \cdot \left(1 - x\right) + \left(-x\right)}{x \cdot \left(\color{blue}{1} + \left(-x\right)\right)} \]
    13. sub-neg18.1%

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

    \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{-2 \cdot \left(1 - x\right) + \left(-x\right)}{x \cdot \left(1 - x\right)}} \]
  7. Step-by-step derivation
    1. unsub-neg18.1%

      \[\leadsto \frac{1}{1 + x} + \frac{\color{blue}{-2 \cdot \left(1 - x\right) - x}}{x \cdot \left(1 - x\right)} \]
  8. Simplified18.1%

    \[\leadsto \frac{1}{1 + x} + \color{blue}{\frac{-2 \cdot \left(1 - x\right) - x}{x \cdot \left(1 - x\right)}} \]
  9. Taylor expanded in x around inf 16.7%

    \[\leadsto \frac{1}{1 + x} + \frac{\color{blue}{x}}{x \cdot \left(1 - x\right)} \]
  10. Taylor expanded in x around 0 3.4%

    \[\leadsto \color{blue}{2} \]
  11. Final simplification3.4%

    \[\leadsto 2 \]
  12. 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 2024041 
(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))))