Data.Approximate.Numerics:blog from approximate-0.2.2.1

Percentage Accurate: 99.7% → 99.9%
Time: 11.3s
Alternatives: 15
Speedup: 1.1×

Specification

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

\\
\frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \sqrt{x}}
\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 15 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: 99.7% accurate, 1.0× speedup?

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

\\
\frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \sqrt{x}}
\end{array}

Alternative 1: 99.9% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{x + -1}{x + \mathsf{fma}\left(4, \sqrt{x}, 1\right)} \cdot 6 \end{array} \]
(FPCore (x)
 :precision binary64
 (* (/ (+ x -1.0) (+ x (fma 4.0 (sqrt x) 1.0))) 6.0))
double code(double x) {
	return ((x + -1.0) / (x + fma(4.0, sqrt(x), 1.0))) * 6.0;
}
function code(x)
	return Float64(Float64(Float64(x + -1.0) / Float64(x + fma(4.0, sqrt(x), 1.0))) * 6.0)
end
code[x_] := N[(N[(N[(x + -1.0), $MachinePrecision] / N[(x + N[(4.0 * N[Sqrt[x], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 6.0), $MachinePrecision]
\begin{array}{l}

\\
\frac{x + -1}{x + \mathsf{fma}\left(4, \sqrt{x}, 1\right)} \cdot 6
\end{array}
Derivation
  1. Initial program 99.8%

    \[\frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. flip--N/A

      \[\leadsto \frac{6 \cdot \color{blue}{\frac{x \cdot x - 1 \cdot 1}{x + 1}}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    2. lift-+.f64N/A

      \[\leadsto \frac{6 \cdot \frac{x \cdot x - 1 \cdot 1}{\color{blue}{x + 1}}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    3. associate-*r/N/A

      \[\leadsto \frac{\color{blue}{\frac{6 \cdot \left(x \cdot x - 1 \cdot 1\right)}{x + 1}}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    4. lift-+.f64N/A

      \[\leadsto \frac{\frac{6 \cdot \left(x \cdot x - 1 \cdot 1\right)}{x + 1}}{\color{blue}{\left(x + 1\right)} + 4 \cdot \sqrt{x}} \]
    5. lift-sqrt.f64N/A

      \[\leadsto \frac{\frac{6 \cdot \left(x \cdot x - 1 \cdot 1\right)}{x + 1}}{\left(x + 1\right) + 4 \cdot \color{blue}{\sqrt{x}}} \]
    6. lift-*.f64N/A

      \[\leadsto \frac{\frac{6 \cdot \left(x \cdot x - 1 \cdot 1\right)}{x + 1}}{\left(x + 1\right) + \color{blue}{4 \cdot \sqrt{x}}} \]
    7. lift-+.f64N/A

      \[\leadsto \frac{\frac{6 \cdot \left(x \cdot x - 1 \cdot 1\right)}{x + 1}}{\color{blue}{\left(x + 1\right) + 4 \cdot \sqrt{x}}} \]
    8. associate-*r/N/A

      \[\leadsto \frac{\color{blue}{6 \cdot \frac{x \cdot x - 1 \cdot 1}{x + 1}}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    9. lift-+.f64N/A

      \[\leadsto \frac{6 \cdot \frac{x \cdot x - 1 \cdot 1}{\color{blue}{x + 1}}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    10. flip--N/A

      \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    11. lift--.f64N/A

      \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    12. *-commutativeN/A

      \[\leadsto \frac{\color{blue}{\left(x - 1\right) \cdot 6}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    13. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{x - 1}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \cdot 6} \]
    14. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{x - 1}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \cdot 6} \]
  4. Applied egg-rr99.9%

    \[\leadsto \color{blue}{\frac{x + -1}{x + \mathsf{fma}\left(4, \sqrt{x}, 1\right)} \cdot 6} \]
  5. Add Preprocessing

Alternative 2: 97.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{\left(x + -1\right) \cdot 6}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \leq -4:\\ \;\;\;\;\frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}\\ \mathbf{else}:\\ \;\;\;\;6 \cdot \frac{x + -1}{\mathsf{fma}\left(\sqrt{x}, 4, x\right)}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (/ (* (+ x -1.0) 6.0) (+ (+ x 1.0) (* 4.0 (sqrt x)))) -4.0)
   (/ (fma x 6.0 -6.0) (fma 4.0 (sqrt x) 1.0))
   (* 6.0 (/ (+ x -1.0) (fma (sqrt x) 4.0 x)))))
double code(double x) {
	double tmp;
	if ((((x + -1.0) * 6.0) / ((x + 1.0) + (4.0 * sqrt(x)))) <= -4.0) {
		tmp = fma(x, 6.0, -6.0) / fma(4.0, sqrt(x), 1.0);
	} else {
		tmp = 6.0 * ((x + -1.0) / fma(sqrt(x), 4.0, x));
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (Float64(Float64(Float64(x + -1.0) * 6.0) / Float64(Float64(x + 1.0) + Float64(4.0 * sqrt(x)))) <= -4.0)
		tmp = Float64(fma(x, 6.0, -6.0) / fma(4.0, sqrt(x), 1.0));
	else
		tmp = Float64(6.0 * Float64(Float64(x + -1.0) / fma(sqrt(x), 4.0, x)));
	end
	return tmp
end
code[x_] := If[LessEqual[N[(N[(N[(x + -1.0), $MachinePrecision] * 6.0), $MachinePrecision] / N[(N[(x + 1.0), $MachinePrecision] + N[(4.0 * N[Sqrt[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -4.0], N[(N[(x * 6.0 + -6.0), $MachinePrecision] / N[(4.0 * N[Sqrt[x], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(6.0 * N[(N[(x + -1.0), $MachinePrecision] / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{\left(x + -1\right) \cdot 6}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \leq -4:\\
\;\;\;\;\frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}\\

\mathbf{else}:\\
\;\;\;\;6 \cdot \frac{x + -1}{\mathsf{fma}\left(\sqrt{x}, 4, x\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 #s(literal 6 binary64) (-.f64 x #s(literal 1 binary64))) (+.f64 (+.f64 x #s(literal 1 binary64)) (*.f64 #s(literal 4 binary64) (sqrt.f64 x)))) < -4

    1. Initial program 99.9%

      \[\frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{1 + 4 \cdot \sqrt{x}}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{4 \cdot \sqrt{x} + 1}} \]
      2. lower-fma.f64N/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}} \]
      3. lower-sqrt.f6498.3

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\mathsf{fma}\left(4, \color{blue}{\sqrt{x}}, 1\right)} \]
    5. Simplified98.3%

      \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}} \]
    6. Step-by-step derivation
      1. sub-negN/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x + \left(\mathsf{neg}\left(1\right)\right)\right)}}{4 \cdot \sqrt{x} + 1} \]
      2. metadata-evalN/A

        \[\leadsto \frac{6 \cdot \left(x + \color{blue}{-1}\right)}{4 \cdot \sqrt{x} + 1} \]
      3. lift-+.f64N/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x + -1\right)}}{4 \cdot \sqrt{x} + 1} \]
      4. lift-sqrt.f64N/A

        \[\leadsto \frac{6 \cdot \left(x + -1\right)}{4 \cdot \color{blue}{\sqrt{x}} + 1} \]
      5. lift-fma.f64N/A

        \[\leadsto \frac{6 \cdot \left(x + -1\right)}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}} \]
      6. lift-+.f64N/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x + -1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      7. metadata-evalN/A

        \[\leadsto \frac{6 \cdot \left(x + \color{blue}{\left(\mathsf{neg}\left(1\right)\right)}\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      8. sub-negN/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      9. lift--.f64N/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      10. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{6 \cdot \left(x - 1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      11. lift-/.f6498.3

        \[\leadsto \color{blue}{\frac{6 \cdot \left(x - 1\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}} \]
      12. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{6 \cdot \left(x - 1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      13. lift--.f64N/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      14. sub-negN/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x + \left(\mathsf{neg}\left(1\right)\right)\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      15. metadata-evalN/A

        \[\leadsto \frac{6 \cdot \left(x + \color{blue}{-1}\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      16. distribute-rgt-inN/A

        \[\leadsto \frac{\color{blue}{x \cdot 6 + -1 \cdot 6}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      17. metadata-evalN/A

        \[\leadsto \frac{x \cdot 6 + \color{blue}{-6}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
      18. lower-fma.f6498.3

        \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(x, 6, -6\right)}}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)} \]
    7. Applied egg-rr98.3%

      \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}} \]

    if -4 < (/.f64 (*.f64 #s(literal 6 binary64) (-.f64 x #s(literal 1 binary64))) (+.f64 (+.f64 x #s(literal 1 binary64)) (*.f64 #s(literal 4 binary64) (sqrt.f64 x))))

    1. Initial program 99.4%

      \[\frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \frac{6 \cdot \color{blue}{\left(x - 1\right)}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{6 \cdot \left(x - 1\right)}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
      3. lift-+.f64N/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\left(x + 1\right)} + 4 \cdot \sqrt{x}} \]
      4. lift-sqrt.f64N/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + 4 \cdot \color{blue}{\sqrt{x}}} \]
      5. lift-*.f64N/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\left(x + 1\right) + \color{blue}{4 \cdot \sqrt{x}}} \]
      6. lift-+.f64N/A

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\left(x + 1\right) + 4 \cdot \sqrt{x}}} \]
      7. clear-numN/A

        \[\leadsto \color{blue}{\frac{1}{\frac{\left(x + 1\right) + 4 \cdot \sqrt{x}}{6 \cdot \left(x - 1\right)}}} \]
      8. lift-*.f64N/A

        \[\leadsto \frac{1}{\frac{\left(x + 1\right) + 4 \cdot \sqrt{x}}{\color{blue}{6 \cdot \left(x - 1\right)}}} \]
      9. associate-/r*N/A

        \[\leadsto \frac{1}{\color{blue}{\frac{\frac{\left(x + 1\right) + 4 \cdot \sqrt{x}}{6}}{x - 1}}} \]
      10. associate-/r/N/A

        \[\leadsto \color{blue}{\frac{1}{\frac{\left(x + 1\right) + 4 \cdot \sqrt{x}}{6}} \cdot \left(x - 1\right)} \]
      11. clear-numN/A

        \[\leadsto \color{blue}{\frac{6}{\left(x + 1\right) + 4 \cdot \sqrt{x}}} \cdot \left(x - 1\right) \]
      12. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{6}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \cdot \left(x - 1\right)} \]
    4. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\frac{-6}{\mathsf{fma}\left(\sqrt{x}, -4, -1\right) - x} \cdot \left(x + -1\right)} \]
    5. Taylor expanded in x around inf

      \[\leadsto \frac{-6}{\color{blue}{-4 \cdot \sqrt{x}} - x} \cdot \left(x + -1\right) \]
    6. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x} \cdot -4} - x} \cdot \left(x + -1\right) \]
      2. lower-*.f64N/A

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x} \cdot -4} - x} \cdot \left(x + -1\right) \]
      3. lower-sqrt.f6497.2

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x}} \cdot -4 - x} \cdot \left(x + -1\right) \]
    7. Simplified97.2%

      \[\leadsto \frac{-6}{\color{blue}{\sqrt{x} \cdot -4} - x} \cdot \left(x + -1\right) \]
    8. Step-by-step derivation
      1. lift-sqrt.f64N/A

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x}} \cdot -4 - x} \cdot \left(x + -1\right) \]
      2. lift-*.f64N/A

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x} \cdot -4} - x} \cdot \left(x + -1\right) \]
      3. lift--.f64N/A

        \[\leadsto \frac{-6}{\color{blue}{\sqrt{x} \cdot -4 - x}} \cdot \left(x + -1\right) \]
      4. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{-6}{\sqrt{x} \cdot -4 - x}} \cdot \left(x + -1\right) \]
      5. lift-+.f64N/A

        \[\leadsto \frac{-6}{\sqrt{x} \cdot -4 - x} \cdot \color{blue}{\left(x + -1\right)} \]
      6. lift-*.f6497.2

        \[\leadsto \color{blue}{\frac{-6}{\sqrt{x} \cdot -4 - x} \cdot \left(x + -1\right)} \]
      7. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{-6}{\sqrt{x} \cdot -4 - x}} \cdot \left(x + -1\right) \]
      8. frac-2negN/A

        \[\leadsto \color{blue}{\frac{\mathsf{neg}\left(-6\right)}{\mathsf{neg}\left(\left(\sqrt{x} \cdot -4 - x\right)\right)}} \cdot \left(x + -1\right) \]
      9. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{6}}{\mathsf{neg}\left(\left(\sqrt{x} \cdot -4 - x\right)\right)} \cdot \left(x + -1\right) \]
      10. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{6}{\mathsf{neg}\left(\left(\sqrt{x} \cdot -4 - x\right)\right)}} \cdot \left(x + -1\right) \]
      11. neg-sub0N/A

        \[\leadsto \frac{6}{\color{blue}{0 - \left(\sqrt{x} \cdot -4 - x\right)}} \cdot \left(x + -1\right) \]
      12. lift--.f64N/A

        \[\leadsto \frac{6}{0 - \color{blue}{\left(\sqrt{x} \cdot -4 - x\right)}} \cdot \left(x + -1\right) \]
      13. associate-+l-N/A

        \[\leadsto \frac{6}{\color{blue}{\left(0 - \sqrt{x} \cdot -4\right) + x}} \cdot \left(x + -1\right) \]
      14. neg-sub0N/A

        \[\leadsto \frac{6}{\color{blue}{\left(\mathsf{neg}\left(\sqrt{x} \cdot -4\right)\right)} + x} \cdot \left(x + -1\right) \]
      15. lift-*.f64N/A

        \[\leadsto \frac{6}{\left(\mathsf{neg}\left(\color{blue}{\sqrt{x} \cdot -4}\right)\right) + x} \cdot \left(x + -1\right) \]
      16. *-commutativeN/A

        \[\leadsto \frac{6}{\left(\mathsf{neg}\left(\color{blue}{-4 \cdot \sqrt{x}}\right)\right) + x} \cdot \left(x + -1\right) \]
      17. distribute-lft-neg-inN/A

        \[\leadsto \frac{6}{\color{blue}{\left(\mathsf{neg}\left(-4\right)\right) \cdot \sqrt{x}} + x} \cdot \left(x + -1\right) \]
      18. metadata-evalN/A

        \[\leadsto \frac{6}{\color{blue}{4} \cdot \sqrt{x} + x} \cdot \left(x + -1\right) \]
      19. lower-fma.f6497.2

        \[\leadsto \frac{6}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \cdot \left(x + -1\right) \]
    9. Applied egg-rr97.2%

      \[\leadsto \color{blue}{\frac{6}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot \left(x + -1\right)} \]
    10. Step-by-step derivation
      1. lift-sqrt.f64N/A

        \[\leadsto \frac{6}{4 \cdot \color{blue}{\sqrt{x}} + x} \cdot \left(x + -1\right) \]
      2. lift-fma.f64N/A

        \[\leadsto \frac{6}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \cdot \left(x + -1\right) \]
      3. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{6}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \cdot \left(x + -1\right) \]
      4. lift-+.f64N/A

        \[\leadsto \frac{6}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot \color{blue}{\left(x + -1\right)} \]
      5. *-commutativeN/A

        \[\leadsto \color{blue}{\left(x + -1\right) \cdot \frac{6}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \]
      6. lift-/.f64N/A

        \[\leadsto \left(x + -1\right) \cdot \color{blue}{\frac{6}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \]
      7. clear-numN/A

        \[\leadsto \left(x + -1\right) \cdot \color{blue}{\frac{1}{\frac{\mathsf{fma}\left(4, \sqrt{x}, x\right)}{6}}} \]
      8. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\left(x + -1\right) \cdot 1}{\frac{\mathsf{fma}\left(4, \sqrt{x}, x\right)}{6}}} \]
      9. div-invN/A

        \[\leadsto \frac{\left(x + -1\right) \cdot 1}{\color{blue}{\mathsf{fma}\left(4, \sqrt{x}, x\right) \cdot \frac{1}{6}}} \]
      10. metadata-evalN/A

        \[\leadsto \frac{\left(x + -1\right) \cdot 1}{\mathsf{fma}\left(4, \sqrt{x}, x\right) \cdot \color{blue}{\frac{1}{6}}} \]
      11. metadata-evalN/A

        \[\leadsto \frac{\left(x + -1\right) \cdot 1}{\mathsf{fma}\left(4, \sqrt{x}, x\right) \cdot \color{blue}{\left(\mathsf{neg}\left(\frac{-1}{6}\right)\right)}} \]
      12. times-fracN/A

        \[\leadsto \color{blue}{\frac{x + -1}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot \frac{1}{\mathsf{neg}\left(\frac{-1}{6}\right)}} \]
      13. metadata-evalN/A

        \[\leadsto \frac{x + -1}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot \frac{1}{\color{blue}{\frac{1}{6}}} \]
      14. metadata-evalN/A

        \[\leadsto \frac{x + -1}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot \color{blue}{6} \]
      15. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{x + -1}{\mathsf{fma}\left(4, \sqrt{x}, x\right)} \cdot 6} \]
      16. lower-/.f6497.4

        \[\leadsto \color{blue}{\frac{x + -1}{\mathsf{fma}\left(4, \sqrt{x}, x\right)}} \cdot 6 \]
      17. lift-fma.f64N/A

        \[\leadsto \frac{x + -1}{\color{blue}{4 \cdot \sqrt{x} + x}} \cdot 6 \]
      18. *-commutativeN/A

        \[\leadsto \frac{x + -1}{\color{blue}{\sqrt{x} \cdot 4} + x} \cdot 6 \]
      19. lower-fma.f6497.4

        \[\leadsto \frac{x + -1}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, x\right)}} \cdot 6 \]
    11. Applied egg-rr97.4%

      \[\leadsto \color{blue}{\frac{x + -1}{\mathsf{fma}\left(\sqrt{x}, 4, x\right)} \cdot 6} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(x + -1\right) \cdot 6}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \leq -4:\\ \;\;\;\;\frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(4, \sqrt{x}, 1\right)}\\ \mathbf{else}:\\ \;\;\;\;6 \cdot \frac{x + -1}{\mathsf{fma}\left(\sqrt{x}, 4, x\right)}\\ \end{array} \]
  5. Add Preprocessing

Developer Target 1: 99.9% accurate, 0.9× speedup?

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

\\
\frac{6}{\frac{\left(x + 1\right) + 4 \cdot \sqrt{x}}{x - 1}}
\end{array}

Reproduce

?
herbie shell --seed 2024218 
(FPCore (x)
  :name "Data.Approximate.Numerics:blog from approximate-0.2.2.1"
  :precision binary64

  :alt
  (! :herbie-platform default (/ 6 (/ (+ (+ x 1) (* 4 (sqrt x))) (- x 1))))

  (/ (* 6.0 (- x 1.0)) (+ (+ x 1.0) (* 4.0 (sqrt x)))))