Data.Approximate.Numerics:blog from approximate-0.2.2.1

Percentage Accurate: 99.7% → 99.9%
Time: 4.3s
Alternatives: 7
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 7 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?

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

\\
6 \cdot \frac{1 - x}{\mathsf{fma}\left(-4, \sqrt{x}, -1\right) - x}
\end{array}
Derivation
  1. Initial program 99.7%

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

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

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

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

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

      \[\leadsto \color{blue}{\frac{x - 1}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \cdot 6} \]
  4. Applied rewrites99.9%

    \[\leadsto \color{blue}{\frac{1 - x}{\mathsf{fma}\left(-4, \sqrt{x}, -1\right) - x} \cdot 6} \]
  5. Final simplification99.9%

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

Alternative 2: 97.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(x - 1\right) \cdot 6\\ \mathbf{if}\;\frac{t\_0}{4 \cdot \sqrt{x} + \left(x + 1\right)} \leq -5:\\ \;\;\;\;\frac{t\_0}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{6 \cdot x}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (* (- x 1.0) 6.0)))
   (if (<= (/ t_0 (+ (* 4.0 (sqrt x)) (+ x 1.0))) -5.0)
     (/ t_0 (fma (sqrt x) 4.0 1.0))
     (/ (* 6.0 x) (fma (sqrt x) 4.0 (- x -1.0))))))
double code(double x) {
	double t_0 = (x - 1.0) * 6.0;
	double tmp;
	if ((t_0 / ((4.0 * sqrt(x)) + (x + 1.0))) <= -5.0) {
		tmp = t_0 / fma(sqrt(x), 4.0, 1.0);
	} else {
		tmp = (6.0 * x) / fma(sqrt(x), 4.0, (x - -1.0));
	}
	return tmp;
}
function code(x)
	t_0 = Float64(Float64(x - 1.0) * 6.0)
	tmp = 0.0
	if (Float64(t_0 / Float64(Float64(4.0 * sqrt(x)) + Float64(x + 1.0))) <= -5.0)
		tmp = Float64(t_0 / fma(sqrt(x), 4.0, 1.0));
	else
		tmp = Float64(Float64(6.0 * x) / fma(sqrt(x), 4.0, Float64(x - -1.0)));
	end
	return tmp
end
code[x_] := Block[{t$95$0 = N[(N[(x - 1.0), $MachinePrecision] * 6.0), $MachinePrecision]}, If[LessEqual[N[(t$95$0 / N[(N[(4.0 * N[Sqrt[x], $MachinePrecision]), $MachinePrecision] + N[(x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -5.0], N[(t$95$0 / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + 1.0), $MachinePrecision]), $MachinePrecision], N[(N[(6.0 * x), $MachinePrecision] / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + N[(x - -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(x - 1\right) \cdot 6\\
\mathbf{if}\;\frac{t\_0}{4 \cdot \sqrt{x} + \left(x + 1\right)} \leq -5:\\
\;\;\;\;\frac{t\_0}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{6 \cdot x}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\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)))) < -5

    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. *-commutativeN/A

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

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
      4. lower-sqrt.f6499.2

        \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\mathsf{fma}\left(\color{blue}{\sqrt{x}}, 4, 1\right)} \]
    5. Applied rewrites99.2%

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

    if -5 < (/.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 99.6%

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

      \[\leadsto \frac{\color{blue}{6 \cdot x}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    4. Step-by-step derivation
      1. lower-*.f6497.6

        \[\leadsto \frac{\color{blue}{6 \cdot x}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
    5. Applied rewrites97.6%

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

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

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

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

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

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

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

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

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

        \[\leadsto \frac{6 \cdot x}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}} \]
    7. Applied rewrites97.6%

      \[\leadsto \frac{6 \cdot x}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.4%

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

Alternative 3: 97.4% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{\left(x - 1\right) \cdot 6}{4 \cdot \sqrt{x} + \left(x + 1\right)} \leq -5:\\ \;\;\;\;\mathsf{fma}\left(4, \sqrt{x}, -1\right) \cdot \mathsf{fma}\left(96, x, 6\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{6 \cdot x}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (/ (* (- x 1.0) 6.0) (+ (* 4.0 (sqrt x)) (+ x 1.0))) -5.0)
   (* (fma 4.0 (sqrt x) -1.0) (fma 96.0 x 6.0))
   (/ (* 6.0 x) (fma (sqrt x) 4.0 (- x -1.0)))))
double code(double x) {
	double tmp;
	if ((((x - 1.0) * 6.0) / ((4.0 * sqrt(x)) + (x + 1.0))) <= -5.0) {
		tmp = fma(4.0, sqrt(x), -1.0) * fma(96.0, x, 6.0);
	} else {
		tmp = (6.0 * x) / fma(sqrt(x), 4.0, (x - -1.0));
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (Float64(Float64(Float64(x - 1.0) * 6.0) / Float64(Float64(4.0 * sqrt(x)) + Float64(x + 1.0))) <= -5.0)
		tmp = Float64(fma(4.0, sqrt(x), -1.0) * fma(96.0, x, 6.0));
	else
		tmp = Float64(Float64(6.0 * x) / fma(sqrt(x), 4.0, Float64(x - -1.0)));
	end
	return tmp
end
code[x_] := If[LessEqual[N[(N[(N[(x - 1.0), $MachinePrecision] * 6.0), $MachinePrecision] / N[(N[(4.0 * N[Sqrt[x], $MachinePrecision]), $MachinePrecision] + N[(x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -5.0], N[(N[(4.0 * N[Sqrt[x], $MachinePrecision] + -1.0), $MachinePrecision] * N[(96.0 * x + 6.0), $MachinePrecision]), $MachinePrecision], N[(N[(6.0 * x), $MachinePrecision] / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + N[(x - -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{\left(x - 1\right) \cdot 6}{4 \cdot \sqrt{x} + \left(x + 1\right)} \leq -5:\\
\;\;\;\;\mathsf{fma}\left(4, \sqrt{x}, -1\right) \cdot \mathsf{fma}\left(96, x, 6\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{6 \cdot x}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\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)))) < -5

    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

      \[\leadsto \color{blue}{\frac{-6}{1 + 4 \cdot \sqrt{x}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

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

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

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

        \[\leadsto \frac{-6}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
      5. lower-sqrt.f6499.2

        \[\leadsto \frac{-6}{\mathsf{fma}\left(\color{blue}{\sqrt{x}}, 4, 1\right)} \]
    5. Applied rewrites99.2%

      \[\leadsto \color{blue}{\frac{-6}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
    6. Step-by-step derivation
      1. Applied rewrites99.2%

        \[\leadsto \frac{-6}{\mathsf{fma}\left(16, x, -1\right)} \cdot \color{blue}{\mathsf{fma}\left(4, \sqrt{x}, -1\right)} \]
      2. Taylor expanded in x around 0

        \[\leadsto \left(6 + 96 \cdot x\right) \cdot \mathsf{fma}\left(\color{blue}{4}, \sqrt{x}, -1\right) \]
      3. Step-by-step derivation
        1. Applied rewrites99.2%

          \[\leadsto \mathsf{fma}\left(96, x, 6\right) \cdot \mathsf{fma}\left(\color{blue}{4}, \sqrt{x}, -1\right) \]

        if -5 < (/.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 99.6%

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

          \[\leadsto \frac{\color{blue}{6 \cdot x}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
        4. Step-by-step derivation
          1. lower-*.f6497.6

            \[\leadsto \frac{\color{blue}{6 \cdot x}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
        5. Applied rewrites97.6%

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

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

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

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

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

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

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

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

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

            \[\leadsto \frac{6 \cdot x}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}} \]
        7. Applied rewrites97.6%

          \[\leadsto \frac{6 \cdot x}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}} \]
      4. Recombined 2 regimes into one program.
      5. Final simplification98.4%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(x - 1\right) \cdot 6}{4 \cdot \sqrt{x} + \left(x + 1\right)} \leq -5:\\ \;\;\;\;\mathsf{fma}\left(4, \sqrt{x}, -1\right) \cdot \mathsf{fma}\left(96, x, 6\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{6 \cdot x}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}\\ \end{array} \]
      6. Add Preprocessing

      Alternative 4: 99.7% accurate, 1.1× speedup?

      \[\begin{array}{l} \\ \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)} \end{array} \]
      (FPCore (x)
       :precision binary64
       (/ (fma x 6.0 -6.0) (fma (sqrt x) 4.0 (- x -1.0))))
      double code(double x) {
      	return fma(x, 6.0, -6.0) / fma(sqrt(x), 4.0, (x - -1.0));
      }
      
      function code(x)
      	return Float64(fma(x, 6.0, -6.0) / fma(sqrt(x), 4.0, Float64(x - -1.0)))
      end
      
      code[x_] := N[(N[(x * 6.0 + -6.0), $MachinePrecision] / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + N[(x - -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, x - -1\right)}
      \end{array}
      
      Derivation
      1. Initial program 99.7%

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

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

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

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

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

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

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

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

          \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(x, 6, \mathsf{neg}\left(6\right)\right)}}{\left(x + 1\right) + 4 \cdot \sqrt{x}} \]
        9. metadata-eval99.8

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

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

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

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

          \[\leadsto \frac{\mathsf{fma}\left(x, 6, -6\right)}{\color{blue}{\sqrt{x} \cdot 4} + \left(x + 1\right)} \]
        14. lower-fma.f6499.8

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

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

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

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

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

          \[\leadsto \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, \color{blue}{x - \left(\mathsf{neg}\left(1\right)\right)}\right)} \]
        20. metadata-eval99.8

          \[\leadsto \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, x - \color{blue}{-1}\right)} \]
      4. Applied rewrites99.8%

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

      Alternative 5: 52.0% accurate, 1.2× speedup?

      \[\begin{array}{l} \\ \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)} \end{array} \]
      (FPCore (x) :precision binary64 (/ (fma x 6.0 -6.0) (fma (sqrt x) 4.0 1.0)))
      double code(double x) {
      	return fma(x, 6.0, -6.0) / fma(sqrt(x), 4.0, 1.0);
      }
      
      function code(x)
      	return Float64(fma(x, 6.0, -6.0) / fma(sqrt(x), 4.0, 1.0))
      end
      
      code[x_] := N[(N[(x * 6.0 + -6.0), $MachinePrecision] / N[(N[Sqrt[x], $MachinePrecision] * 4.0 + 1.0), $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \frac{\mathsf{fma}\left(x, 6, -6\right)}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}
      \end{array}
      
      Derivation
      1. Initial program 99.7%

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

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

          \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
        4. lower-sqrt.f6453.2

          \[\leadsto \frac{6 \cdot \left(x - 1\right)}{\mathsf{fma}\left(\color{blue}{\sqrt{x}}, 4, 1\right)} \]
      5. Applied rewrites53.2%

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

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

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

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

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

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

          \[\leadsto \frac{x \cdot 6 + \color{blue}{-6}}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)} \]
        7. lower-fma.f6453.1

          \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(x, 6, -6\right)}}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)} \]
      7. Applied rewrites53.1%

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

      Alternative 6: 51.7% accurate, 1.9× speedup?

      \[\begin{array}{l} \\ 6 \cdot \mathsf{fma}\left(4, \sqrt{x}, -1\right) \end{array} \]
      (FPCore (x) :precision binary64 (* 6.0 (fma 4.0 (sqrt x) -1.0)))
      double code(double x) {
      	return 6.0 * fma(4.0, sqrt(x), -1.0);
      }
      
      function code(x)
      	return Float64(6.0 * fma(4.0, sqrt(x), -1.0))
      end
      
      code[x_] := N[(6.0 * N[(4.0 * N[Sqrt[x], $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      6 \cdot \mathsf{fma}\left(4, \sqrt{x}, -1\right)
      \end{array}
      
      Derivation
      1. Initial program 99.7%

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

        \[\leadsto \color{blue}{\frac{-6}{1 + 4 \cdot \sqrt{x}}} \]
      4. Step-by-step derivation
        1. lower-/.f64N/A

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

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

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

          \[\leadsto \frac{-6}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
        5. lower-sqrt.f6450.5

          \[\leadsto \frac{-6}{\mathsf{fma}\left(\color{blue}{\sqrt{x}}, 4, 1\right)} \]
      5. Applied rewrites50.5%

        \[\leadsto \color{blue}{\frac{-6}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
      6. Step-by-step derivation
        1. Applied rewrites50.5%

          \[\leadsto \frac{-6}{\mathsf{fma}\left(16, x, -1\right)} \cdot \color{blue}{\mathsf{fma}\left(4, \sqrt{x}, -1\right)} \]
        2. Taylor expanded in x around 0

          \[\leadsto 6 \cdot \mathsf{fma}\left(\color{blue}{4}, \sqrt{x}, -1\right) \]
        3. Step-by-step derivation
          1. Applied rewrites53.0%

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

          Alternative 7: 4.4% accurate, 2.0× speedup?

          \[\begin{array}{l} \\ \left(4 \cdot \sqrt{x}\right) \cdot 6 \end{array} \]
          (FPCore (x) :precision binary64 (* (* 4.0 (sqrt x)) 6.0))
          double code(double x) {
          	return (4.0 * sqrt(x)) * 6.0;
          }
          
          real(8) function code(x)
              real(8), intent (in) :: x
              code = (4.0d0 * sqrt(x)) * 6.0d0
          end function
          
          public static double code(double x) {
          	return (4.0 * Math.sqrt(x)) * 6.0;
          }
          
          def code(x):
          	return (4.0 * math.sqrt(x)) * 6.0
          
          function code(x)
          	return Float64(Float64(4.0 * sqrt(x)) * 6.0)
          end
          
          function tmp = code(x)
          	tmp = (4.0 * sqrt(x)) * 6.0;
          end
          
          code[x_] := N[(N[(4.0 * N[Sqrt[x], $MachinePrecision]), $MachinePrecision] * 6.0), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          \left(4 \cdot \sqrt{x}\right) \cdot 6
          \end{array}
          
          Derivation
          1. Initial program 99.7%

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

            \[\leadsto \color{blue}{\frac{-6}{1 + 4 \cdot \sqrt{x}}} \]
          4. Step-by-step derivation
            1. lower-/.f64N/A

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

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

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

              \[\leadsto \frac{-6}{\color{blue}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
            5. lower-sqrt.f6450.5

              \[\leadsto \frac{-6}{\mathsf{fma}\left(\color{blue}{\sqrt{x}}, 4, 1\right)} \]
          5. Applied rewrites50.5%

            \[\leadsto \color{blue}{\frac{-6}{\mathsf{fma}\left(\sqrt{x}, 4, 1\right)}} \]
          6. Step-by-step derivation
            1. Applied rewrites50.5%

              \[\leadsto \frac{-6}{\mathsf{fma}\left(16, x, -1\right)} \cdot \color{blue}{\mathsf{fma}\left(4, \sqrt{x}, -1\right)} \]
            2. Taylor expanded in x around 0

              \[\leadsto 6 \cdot \mathsf{fma}\left(\color{blue}{4}, \sqrt{x}, -1\right) \]
            3. Step-by-step derivation
              1. Applied rewrites53.0%

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

                \[\leadsto 6 \cdot \left(-4 \cdot \color{blue}{\left(\sqrt{x} \cdot {\left(\sqrt{-1}\right)}^{2}\right)}\right) \]
              3. Step-by-step derivation
                1. Applied rewrites4.4%

                  \[\leadsto 6 \cdot \left(\sqrt{x} \cdot \color{blue}{4}\right) \]
                2. Final simplification4.4%

                  \[\leadsto \left(4 \cdot \sqrt{x}\right) \cdot 6 \]
                3. 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 2024308 
                (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)))))