ENA, Section 1.4, Mentioned, B

Percentage Accurate: 87.8% → 99.5%
Time: 6.4s
Alternatives: 5
Speedup: 1.1×

Specification

?
\[0.999 \leq x \land x \leq 1.001\]
\[\begin{array}{l} \\ \frac{10}{1 - x \cdot x} \end{array} \]
(FPCore (x) :precision binary64 (/ 10.0 (- 1.0 (* x x))))
double code(double x) {
	return 10.0 / (1.0 - (x * x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 10.0d0 / (1.0d0 - (x * x))
end function
public static double code(double x) {
	return 10.0 / (1.0 - (x * x));
}
def code(x):
	return 10.0 / (1.0 - (x * x))
function code(x)
	return Float64(10.0 / Float64(1.0 - Float64(x * x)))
end
function tmp = code(x)
	tmp = 10.0 / (1.0 - (x * x));
end
code[x_] := N[(10.0 / N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{10}{1 - x \cdot 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 5 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: 87.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{10}{1 - x \cdot x} \end{array} \]
(FPCore (x) :precision binary64 (/ 10.0 (- 1.0 (* x x))))
double code(double x) {
	return 10.0 / (1.0 - (x * x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 10.0d0 / (1.0d0 - (x * x))
end function
public static double code(double x) {
	return 10.0 / (1.0 - (x * x));
}
def code(x):
	return 10.0 / (1.0 - (x * x))
function code(x)
	return Float64(10.0 / Float64(1.0 - Float64(x * x)))
end
function tmp = code(x)
	tmp = 10.0 / (1.0 - (x * x));
end
code[x_] := N[(10.0 / N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{10}{1 - x \cdot x}
\end{array}

Alternative 1: 99.5% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 - {x}^{4}\\ \frac{-10 \cdot t\_0}{\mathsf{fma}\left(t\_0, \left(x - 1\right) \cdot x, t\_0 \cdot \left(x - 1\right)\right)} \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (- 1.0 (pow x 4.0))))
   (/ (* -10.0 t_0) (fma t_0 (* (- x 1.0) x) (* t_0 (- x 1.0))))))
double code(double x) {
	double t_0 = 1.0 - pow(x, 4.0);
	return (-10.0 * t_0) / fma(t_0, ((x - 1.0) * x), (t_0 * (x - 1.0)));
}
function code(x)
	t_0 = Float64(1.0 - (x ^ 4.0))
	return Float64(Float64(-10.0 * t_0) / fma(t_0, Float64(Float64(x - 1.0) * x), Float64(t_0 * Float64(x - 1.0))))
end
code[x_] := Block[{t$95$0 = N[(1.0 - N[Power[x, 4.0], $MachinePrecision]), $MachinePrecision]}, N[(N[(-10.0 * t$95$0), $MachinePrecision] / N[(t$95$0 * N[(N[(x - 1.0), $MachinePrecision] * x), $MachinePrecision] + N[(t$95$0 * N[(x - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 - {x}^{4}\\
\frac{-10 \cdot t\_0}{\mathsf{fma}\left(t\_0, \left(x - 1\right) \cdot x, t\_0 \cdot \left(x - 1\right)\right)}
\end{array}
\end{array}
Derivation
  1. Initial program 87.8%

    \[\frac{10}{1 - x \cdot x} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{10}{1 - x \cdot x}} \]
    2. lift--.f64N/A

      \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
    3. lift-*.f64N/A

      \[\leadsto \frac{10}{1 - \color{blue}{x \cdot x}} \]
    4. rem-square-sqrtN/A

      \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\left(\sqrt{x} \cdot \sqrt{x}\right)}} \]
    5. sqrt-prodN/A

      \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\sqrt{x \cdot x}}} \]
    6. sqr-neg-revN/A

      \[\leadsto \frac{10}{1 - x \cdot \sqrt{\color{blue}{\left(\mathsf{neg}\left(x\right)\right) \cdot \left(\mathsf{neg}\left(x\right)\right)}}} \]
    7. pow2N/A

      \[\leadsto \frac{10}{1 - x \cdot \sqrt{\color{blue}{{\left(\mathsf{neg}\left(x\right)\right)}^{2}}}} \]
    8. sqrt-pow1N/A

      \[\leadsto \frac{10}{1 - x \cdot \color{blue}{{\left(\mathsf{neg}\left(x\right)\right)}^{\left(\frac{2}{2}\right)}}} \]
    9. metadata-evalN/A

      \[\leadsto \frac{10}{1 - x \cdot {\left(\mathsf{neg}\left(x\right)\right)}^{\color{blue}{1}}} \]
    10. unpow1N/A

      \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\left(\mathsf{neg}\left(x\right)\right)}} \]
    11. distribute-rgt-neg-inN/A

      \[\leadsto \frac{10}{1 - \color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right)}} \]
    12. sqr-abs-revN/A

      \[\leadsto \frac{10}{1 - \left(\mathsf{neg}\left(\color{blue}{\left|x\right| \cdot \left|x\right|}\right)\right)} \]
    13. sqr-neg-revN/A

      \[\leadsto \frac{10}{1 - \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(\left|x\right|\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}\right)\right)} \]
    14. distribute-lft-neg-inN/A

      \[\leadsto \frac{10}{1 - \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\left|x\right|\right)\right)\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}} \]
    15. fp-cancel-sign-sub-invN/A

      \[\leadsto \frac{10}{\color{blue}{1 + \left(\mathsf{neg}\left(\left|x\right|\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}} \]
    16. sqr-neg-revN/A

      \[\leadsto \frac{10}{1 + \color{blue}{\left|x\right| \cdot \left|x\right|}} \]
    17. sqr-abs-revN/A

      \[\leadsto \frac{10}{1 + \color{blue}{x \cdot x}} \]
    18. lift-*.f64N/A

      \[\leadsto \frac{10}{1 + \color{blue}{x \cdot x}} \]
    19. frac-2negN/A

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

      \[\leadsto \color{blue}{\frac{\mathsf{neg}\left(10\right)}{\mathsf{neg}\left(\left(1 + x \cdot x\right)\right)}} \]
    21. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{-10}}{\mathsf{neg}\left(\left(1 + x \cdot x\right)\right)} \]
    22. +-commutativeN/A

      \[\leadsto \frac{-10}{\mathsf{neg}\left(\color{blue}{\left(x \cdot x + 1\right)}\right)} \]
    23. distribute-neg-inN/A

      \[\leadsto \frac{-10}{\color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right) + \left(\mathsf{neg}\left(1\right)\right)}} \]
  4. Applied rewrites99.5%

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

      \[\leadsto \frac{-10}{\color{blue}{x \cdot x + -1}} \]
    2. difference-of-sqr--1N/A

      \[\leadsto \frac{-10}{\color{blue}{\left(x + 1\right) \cdot \left(x - 1\right)}} \]
    3. difference-of-sqr-1-revN/A

      \[\leadsto \frac{-10}{\color{blue}{x \cdot x - 1}} \]
    4. pow2N/A

      \[\leadsto \frac{-10}{\color{blue}{{x}^{2}} - 1} \]
    5. pow-to-expN/A

      \[\leadsto \frac{-10}{\color{blue}{e^{\log x \cdot 2}} - 1} \]
    6. rem-log-expN/A

      \[\leadsto \frac{-10}{e^{\color{blue}{\log \left(e^{\log x \cdot 2}\right)}} - 1} \]
    7. pow-to-expN/A

      \[\leadsto \frac{-10}{e^{\log \color{blue}{\left({x}^{2}\right)}} - 1} \]
    8. pow2N/A

      \[\leadsto \frac{-10}{e^{\log \color{blue}{\left(x \cdot x\right)}} - 1} \]
    9. lift-*.f64N/A

      \[\leadsto \frac{-10}{e^{\log \color{blue}{\left(x \cdot x\right)}} - 1} \]
    10. lower-expm1.f64N/A

      \[\leadsto \frac{-10}{\color{blue}{\mathsf{expm1}\left(\log \left(x \cdot x\right)\right)}} \]
    11. lift-*.f64N/A

      \[\leadsto \frac{-10}{\mathsf{expm1}\left(\log \color{blue}{\left(x \cdot x\right)}\right)} \]
    12. pow2N/A

      \[\leadsto \frac{-10}{\mathsf{expm1}\left(\log \color{blue}{\left({x}^{2}\right)}\right)} \]
    13. log-powN/A

      \[\leadsto \frac{-10}{\mathsf{expm1}\left(\color{blue}{2 \cdot \log x}\right)} \]
    14. lower-*.f64N/A

      \[\leadsto \frac{-10}{\mathsf{expm1}\left(\color{blue}{2 \cdot \log x}\right)} \]
    15. lower-log.f6499.4

      \[\leadsto \frac{-10}{\mathsf{expm1}\left(2 \cdot \color{blue}{\log x}\right)} \]
  6. Applied rewrites99.4%

    \[\leadsto \frac{-10}{\color{blue}{\mathsf{expm1}\left(2 \cdot \log x\right)}} \]
  7. Applied rewrites99.5%

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

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

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\left(1 - {x}^{4}\right) \cdot \color{blue}{\left(x \cdot x + -1\right)}} \]
    3. difference-of-sqr--1N/A

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\left(1 - {x}^{4}\right) \cdot \color{blue}{\left(\left(x + 1\right) \cdot \left(x - 1\right)\right)}} \]
    4. rem-square-sqrtN/A

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

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

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

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

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

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

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

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

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\left(1 - {x}^{4}\right) \cdot \left(\left(x - 1\right) \cdot \left(\sqrt{x} \cdot \color{blue}{\sqrt{x}} + 1\right)\right)} \]
    13. rem-square-sqrtN/A

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\left(1 - {x}^{4}\right) \cdot \left(\left(x - 1\right) \cdot \left(\color{blue}{x} + 1\right)\right)} \]
    14. distribute-lft-inN/A

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\left(1 - {x}^{4}\right) \cdot \color{blue}{\left(\left(x - 1\right) \cdot x + \left(x - 1\right) \cdot 1\right)}} \]
    15. distribute-lft-inN/A

      \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\color{blue}{\left(1 - {x}^{4}\right) \cdot \left(\left(x - 1\right) \cdot x\right) + \left(1 - {x}^{4}\right) \cdot \left(\left(x - 1\right) \cdot 1\right)}} \]
  9. Applied rewrites99.5%

    \[\leadsto \frac{-10 \cdot \left(1 - {x}^{4}\right)}{\color{blue}{\mathsf{fma}\left(1 - {x}^{4}, \left(x - 1\right) \cdot x, \left(1 - {x}^{4}\right) \cdot \left(x - 1\right)\right)}} \]
  10. Add Preprocessing

Alternative 2: 13.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{10}{1 - x \cdot x} \leq -5000:\\ \;\;\;\;\left(-10 \cdot x\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(x, x, 1\right) \cdot 10\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (/ 10.0 (- 1.0 (* x x))) -5000.0)
   (* (* -10.0 x) x)
   (* (fma x x 1.0) 10.0)))
double code(double x) {
	double tmp;
	if ((10.0 / (1.0 - (x * x))) <= -5000.0) {
		tmp = (-10.0 * x) * x;
	} else {
		tmp = fma(x, x, 1.0) * 10.0;
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (Float64(10.0 / Float64(1.0 - Float64(x * x))) <= -5000.0)
		tmp = Float64(Float64(-10.0 * x) * x);
	else
		tmp = Float64(fma(x, x, 1.0) * 10.0);
	end
	return tmp
end
code[x_] := If[LessEqual[N[(10.0 / N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -5000.0], N[(N[(-10.0 * x), $MachinePrecision] * x), $MachinePrecision], N[(N[(x * x + 1.0), $MachinePrecision] * 10.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{10}{1 - x \cdot x} \leq -5000:\\
\;\;\;\;\left(-10 \cdot x\right) \cdot x\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(x, x, 1\right) \cdot 10\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 #s(literal 10 binary64) (-.f64 #s(literal 1 binary64) (*.f64 x x))) < -5e3

    1. Initial program 86.7%

      \[\frac{10}{1 - x \cdot x} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{10 + 10 \cdot {x}^{2}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{10 \cdot {x}^{2} + 10} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot 10} + 10 \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, 10, 10\right)} \]
      4. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
      5. lower-*.f641.5

        \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
    5. Applied rewrites1.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, 10, 10\right)} \]
    6. Step-by-step derivation
      1. Applied rewrites1.5%

        \[\leadsto \mathsf{fma}\left(x, x, 1\right) \cdot \color{blue}{10} \]
      2. Applied rewrites11.9%

        \[\leadsto \mathsf{fma}\left(-x, x, 1\right) \cdot 10 \]
      3. Taylor expanded in x around inf

        \[\leadsto -10 \cdot \color{blue}{{x}^{2}} \]
      4. Step-by-step derivation
        1. Applied rewrites13.5%

          \[\leadsto \left(-10 \cdot x\right) \cdot \color{blue}{x} \]

        if -5e3 < (/.f64 #s(literal 10 binary64) (-.f64 #s(literal 1 binary64) (*.f64 x x)))

        1. Initial program 88.3%

          \[\frac{10}{1 - x \cdot x} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{10 + 10 \cdot {x}^{2}} \]
        4. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \color{blue}{10 \cdot {x}^{2} + 10} \]
          2. *-commutativeN/A

            \[\leadsto \color{blue}{{x}^{2} \cdot 10} + 10 \]
          3. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, 10, 10\right)} \]
          4. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
          5. lower-*.f6413.7

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
        5. Applied rewrites13.7%

          \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, 10, 10\right)} \]
        6. Step-by-step derivation
          1. Applied rewrites13.7%

            \[\leadsto \mathsf{fma}\left(x, x, 1\right) \cdot \color{blue}{10} \]
        7. Recombined 2 regimes into one program.
        8. Add Preprocessing

        Alternative 3: 13.5% accurate, 0.8× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;1 - x \cdot x \leq -1 \cdot 10^{-6}:\\ \;\;\;\;\left(-10 \cdot x\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;10\\ \end{array} \end{array} \]
        (FPCore (x)
         :precision binary64
         (if (<= (- 1.0 (* x x)) -1e-6) (* (* -10.0 x) x) 10.0))
        double code(double x) {
        	double tmp;
        	if ((1.0 - (x * x)) <= -1e-6) {
        		tmp = (-10.0 * x) * x;
        	} else {
        		tmp = 10.0;
        	}
        	return tmp;
        }
        
        real(8) function code(x)
            real(8), intent (in) :: x
            real(8) :: tmp
            if ((1.0d0 - (x * x)) <= (-1d-6)) then
                tmp = ((-10.0d0) * x) * x
            else
                tmp = 10.0d0
            end if
            code = tmp
        end function
        
        public static double code(double x) {
        	double tmp;
        	if ((1.0 - (x * x)) <= -1e-6) {
        		tmp = (-10.0 * x) * x;
        	} else {
        		tmp = 10.0;
        	}
        	return tmp;
        }
        
        def code(x):
        	tmp = 0
        	if (1.0 - (x * x)) <= -1e-6:
        		tmp = (-10.0 * x) * x
        	else:
        		tmp = 10.0
        	return tmp
        
        function code(x)
        	tmp = 0.0
        	if (Float64(1.0 - Float64(x * x)) <= -1e-6)
        		tmp = Float64(Float64(-10.0 * x) * x);
        	else
        		tmp = 10.0;
        	end
        	return tmp
        end
        
        function tmp_2 = code(x)
        	tmp = 0.0;
        	if ((1.0 - (x * x)) <= -1e-6)
        		tmp = (-10.0 * x) * x;
        	else
        		tmp = 10.0;
        	end
        	tmp_2 = tmp;
        end
        
        code[x_] := If[LessEqual[N[(1.0 - N[(x * x), $MachinePrecision]), $MachinePrecision], -1e-6], N[(N[(-10.0 * x), $MachinePrecision] * x), $MachinePrecision], 10.0]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        \mathbf{if}\;1 - x \cdot x \leq -1 \cdot 10^{-6}:\\
        \;\;\;\;\left(-10 \cdot x\right) \cdot x\\
        
        \mathbf{else}:\\
        \;\;\;\;10\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (-.f64 #s(literal 1 binary64) (*.f64 x x)) < -9.99999999999999955e-7

          1. Initial program 86.7%

            \[\frac{10}{1 - x \cdot x} \]
          2. Add Preprocessing
          3. Taylor expanded in x around 0

            \[\leadsto \color{blue}{10 + 10 \cdot {x}^{2}} \]
          4. Step-by-step derivation
            1. +-commutativeN/A

              \[\leadsto \color{blue}{10 \cdot {x}^{2} + 10} \]
            2. *-commutativeN/A

              \[\leadsto \color{blue}{{x}^{2} \cdot 10} + 10 \]
            3. lower-fma.f64N/A

              \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, 10, 10\right)} \]
            4. unpow2N/A

              \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
            5. lower-*.f641.5

              \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, 10, 10\right) \]
          5. Applied rewrites1.5%

            \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, 10, 10\right)} \]
          6. Step-by-step derivation
            1. Applied rewrites1.5%

              \[\leadsto \mathsf{fma}\left(x, x, 1\right) \cdot \color{blue}{10} \]
            2. Applied rewrites11.9%

              \[\leadsto \mathsf{fma}\left(-x, x, 1\right) \cdot 10 \]
            3. Taylor expanded in x around inf

              \[\leadsto -10 \cdot \color{blue}{{x}^{2}} \]
            4. Step-by-step derivation
              1. Applied rewrites13.5%

                \[\leadsto \left(-10 \cdot x\right) \cdot \color{blue}{x} \]

              if -9.99999999999999955e-7 < (-.f64 #s(literal 1 binary64) (*.f64 x x))

              1. Initial program 88.3%

                \[\frac{10}{1 - x \cdot x} \]
              2. Add Preprocessing
              3. Taylor expanded in x around 0

                \[\leadsto \color{blue}{10} \]
              4. Step-by-step derivation
                1. Applied rewrites13.5%

                  \[\leadsto \color{blue}{10} \]
              5. Recombined 2 regimes into one program.
              6. Add Preprocessing

              Alternative 4: 99.6% accurate, 1.1× speedup?

              \[\begin{array}{l} \\ \frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \end{array} \]
              (FPCore (x) :precision binary64 (/ -10.0 (fma x x -1.0)))
              double code(double x) {
              	return -10.0 / fma(x, x, -1.0);
              }
              
              function code(x)
              	return Float64(-10.0 / fma(x, x, -1.0))
              end
              
              code[x_] := N[(-10.0 / N[(x * x + -1.0), $MachinePrecision]), $MachinePrecision]
              
              \begin{array}{l}
              
              \\
              \frac{-10}{\mathsf{fma}\left(x, x, -1\right)}
              \end{array}
              
              Derivation
              1. Initial program 87.8%

                \[\frac{10}{1 - x \cdot x} \]
              2. Add Preprocessing
              3. Step-by-step derivation
                1. lift-/.f64N/A

                  \[\leadsto \color{blue}{\frac{10}{1 - x \cdot x}} \]
                2. lift--.f64N/A

                  \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
                3. lift-*.f64N/A

                  \[\leadsto \frac{10}{1 - \color{blue}{x \cdot x}} \]
                4. rem-square-sqrtN/A

                  \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\left(\sqrt{x} \cdot \sqrt{x}\right)}} \]
                5. sqrt-prodN/A

                  \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\sqrt{x \cdot x}}} \]
                6. sqr-neg-revN/A

                  \[\leadsto \frac{10}{1 - x \cdot \sqrt{\color{blue}{\left(\mathsf{neg}\left(x\right)\right) \cdot \left(\mathsf{neg}\left(x\right)\right)}}} \]
                7. pow2N/A

                  \[\leadsto \frac{10}{1 - x \cdot \sqrt{\color{blue}{{\left(\mathsf{neg}\left(x\right)\right)}^{2}}}} \]
                8. sqrt-pow1N/A

                  \[\leadsto \frac{10}{1 - x \cdot \color{blue}{{\left(\mathsf{neg}\left(x\right)\right)}^{\left(\frac{2}{2}\right)}}} \]
                9. metadata-evalN/A

                  \[\leadsto \frac{10}{1 - x \cdot {\left(\mathsf{neg}\left(x\right)\right)}^{\color{blue}{1}}} \]
                10. unpow1N/A

                  \[\leadsto \frac{10}{1 - x \cdot \color{blue}{\left(\mathsf{neg}\left(x\right)\right)}} \]
                11. distribute-rgt-neg-inN/A

                  \[\leadsto \frac{10}{1 - \color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right)}} \]
                12. sqr-abs-revN/A

                  \[\leadsto \frac{10}{1 - \left(\mathsf{neg}\left(\color{blue}{\left|x\right| \cdot \left|x\right|}\right)\right)} \]
                13. sqr-neg-revN/A

                  \[\leadsto \frac{10}{1 - \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(\left|x\right|\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}\right)\right)} \]
                14. distribute-lft-neg-inN/A

                  \[\leadsto \frac{10}{1 - \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\left|x\right|\right)\right)\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}} \]
                15. fp-cancel-sign-sub-invN/A

                  \[\leadsto \frac{10}{\color{blue}{1 + \left(\mathsf{neg}\left(\left|x\right|\right)\right) \cdot \left(\mathsf{neg}\left(\left|x\right|\right)\right)}} \]
                16. sqr-neg-revN/A

                  \[\leadsto \frac{10}{1 + \color{blue}{\left|x\right| \cdot \left|x\right|}} \]
                17. sqr-abs-revN/A

                  \[\leadsto \frac{10}{1 + \color{blue}{x \cdot x}} \]
                18. lift-*.f64N/A

                  \[\leadsto \frac{10}{1 + \color{blue}{x \cdot x}} \]
                19. frac-2negN/A

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

                  \[\leadsto \color{blue}{\frac{\mathsf{neg}\left(10\right)}{\mathsf{neg}\left(\left(1 + x \cdot x\right)\right)}} \]
                21. metadata-evalN/A

                  \[\leadsto \frac{\color{blue}{-10}}{\mathsf{neg}\left(\left(1 + x \cdot x\right)\right)} \]
                22. +-commutativeN/A

                  \[\leadsto \frac{-10}{\mathsf{neg}\left(\color{blue}{\left(x \cdot x + 1\right)}\right)} \]
                23. distribute-neg-inN/A

                  \[\leadsto \frac{-10}{\color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right) + \left(\mathsf{neg}\left(1\right)\right)}} \]
              4. Applied rewrites99.5%

                \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
              5. Add Preprocessing

              Alternative 5: 9.5% accurate, 20.0× speedup?

              \[\begin{array}{l} \\ 10 \end{array} \]
              (FPCore (x) :precision binary64 10.0)
              double code(double x) {
              	return 10.0;
              }
              
              real(8) function code(x)
                  real(8), intent (in) :: x
                  code = 10.0d0
              end function
              
              public static double code(double x) {
              	return 10.0;
              }
              
              def code(x):
              	return 10.0
              
              function code(x)
              	return 10.0
              end
              
              function tmp = code(x)
              	tmp = 10.0;
              end
              
              code[x_] := 10.0
              
              \begin{array}{l}
              
              \\
              10
              \end{array}
              
              Derivation
              1. Initial program 87.8%

                \[\frac{10}{1 - x \cdot x} \]
              2. Add Preprocessing
              3. Taylor expanded in x around 0

                \[\leadsto \color{blue}{10} \]
              4. Step-by-step derivation
                1. Applied rewrites9.4%

                  \[\leadsto \color{blue}{10} \]
                2. Add Preprocessing

                Reproduce

                ?
                herbie shell --seed 2024326 
                (FPCore (x)
                  :name "ENA, Section 1.4, Mentioned, B"
                  :precision binary64
                  :pre (and (<= 0.999 x) (<= x 1.001))
                  (/ 10.0 (- 1.0 (* x x))))