ENA, Section 1.4, Mentioned, B

Percentage Accurate: 87.7% → 99.6%
Time: 4.9s
Alternatives: 5
Speedup: 1.0×

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: 87.7% 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: 99.6% accurate, 0.1× 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 87.7%

    \[\frac{10}{1 - x \cdot x} \]
  2. Step-by-step derivation
    1. sub-neg87.7%

      \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
    2. +-commutative87.7%

      \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
    3. neg-sub087.7%

      \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
    4. associate-+l-87.7%

      \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
    5. sub0-neg87.7%

      \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
    6. neg-mul-187.7%

      \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
    7. associate-/r*87.7%

      \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
    8. metadata-eval87.7%

      \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
    9. fma-neg99.6%

      \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
    10. metadata-eval99.6%

      \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
  4. Final simplification99.6%

    \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \]

Alternative 2: 13.5% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \cdot x \leq 1:\\ \;\;\;\;\frac{10}{x \cdot x}\\ \mathbf{else}:\\ \;\;\;\;-10\\ \end{array} \end{array} \]
(FPCore (x) :precision binary64 (if (<= (* x x) 1.0) (/ 10.0 (* x x)) -10.0))
double code(double x) {
	double tmp;
	if ((x * x) <= 1.0) {
		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 ((x * x) <= 1.0d0) 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 ((x * x) <= 1.0) {
		tmp = 10.0 / (x * x);
	} else {
		tmp = -10.0;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x * x) <= 1.0:
		tmp = 10.0 / (x * x)
	else:
		tmp = -10.0
	return tmp
function code(x)
	tmp = 0.0
	if (Float64(x * x) <= 1.0)
		tmp = Float64(10.0 / Float64(x * x));
	else
		tmp = -10.0;
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x * x) <= 1.0)
		tmp = 10.0 / (x * x);
	else
		tmp = -10.0;
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[N[(x * x), $MachinePrecision], 1.0], N[(10.0 / N[(x * x), $MachinePrecision]), $MachinePrecision], -10.0]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \cdot x \leq 1:\\
\;\;\;\;\frac{10}{x \cdot x}\\

\mathbf{else}:\\
\;\;\;\;-10\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 x x) < 1

    1. Initial program 88.3%

      \[\frac{10}{1 - x \cdot x} \]
    2. Step-by-step derivation
      1. sub-neg88.3%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      2. +-commutative88.3%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
      3. neg-sub088.3%

        \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
      4. associate-+l-88.3%

        \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
      5. sub0-neg88.3%

        \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
      6. neg-mul-188.3%

        \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
      7. associate-/r*88.3%

        \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
      8. metadata-eval88.3%

        \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
      9. fma-neg99.6%

        \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
      10. metadata-eval99.6%

        \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
    4. Step-by-step derivation
      1. frac-2neg99.6%

        \[\leadsto \color{blue}{\frac{--10}{-\mathsf{fma}\left(x, x, -1\right)}} \]
      2. metadata-eval99.6%

        \[\leadsto \frac{\color{blue}{10}}{-\mathsf{fma}\left(x, x, -1\right)} \]
      3. fma-udef88.3%

        \[\leadsto \frac{10}{-\color{blue}{\left(x \cdot x + -1\right)}} \]
      4. distribute-neg-in88.3%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + \left(--1\right)}} \]
      5. metadata-eval88.3%

        \[\leadsto \frac{10}{\left(-x \cdot x\right) + \color{blue}{1}} \]
      6. +-commutative88.3%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      7. sub-neg88.3%

        \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
      8. add-sqr-sqrt88.3%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x}} \cdot \sqrt{\frac{10}{1 - x \cdot x}}} \]
      9. sqrt-unprod88.3%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}}} \]
      10. pow1/288.3%

        \[\leadsto \color{blue}{{\left(\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}\right)}^{0.5}} \]
      11. pow288.3%

        \[\leadsto {\color{blue}{\left({\left(\frac{10}{1 - x \cdot x}\right)}^{2}\right)}}^{0.5} \]
      12. metadata-eval88.3%

        \[\leadsto {\left({\left(\frac{\color{blue}{--10}}{1 - x \cdot x}\right)}^{2}\right)}^{0.5} \]
      13. sub-neg88.3%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{1 + \left(-x \cdot x\right)}}\right)}^{2}\right)}^{0.5} \]
      14. +-commutative88.3%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{\left(-x \cdot x\right) + 1}}\right)}^{2}\right)}^{0.5} \]
      15. metadata-eval88.3%

        \[\leadsto {\left({\left(\frac{--10}{\left(-x \cdot x\right) + \color{blue}{\left(--1\right)}}\right)}^{2}\right)}^{0.5} \]
      16. distribute-neg-in88.3%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{-\left(x \cdot x + -1\right)}}\right)}^{2}\right)}^{0.5} \]
      17. fma-udef99.6%

        \[\leadsto {\left({\left(\frac{--10}{-\color{blue}{\mathsf{fma}\left(x, x, -1\right)}}\right)}^{2}\right)}^{0.5} \]
      18. frac-2neg99.6%

        \[\leadsto {\left({\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{2}\right)}^{0.5} \]
      19. pow299.6%

        \[\leadsto {\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \cdot \frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      20. frac-times99.6%

        \[\leadsto {\color{blue}{\left(\frac{-10 \cdot -10}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      21. metadata-eval99.6%

        \[\leadsto {\left(\frac{\color{blue}{100}}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}^{0.5} \]
      22. pow299.6%

        \[\leadsto {\left(\frac{100}{\color{blue}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}\right)}^{0.5} \]
    5. Applied egg-rr99.6%

      \[\leadsto \color{blue}{{\left(\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}\right)}^{0.5}} \]
    6. Step-by-step derivation
      1. unpow1/299.6%

        \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    7. Simplified99.6%

      \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    8. Taylor expanded in x around inf 13.5%

      \[\leadsto \color{blue}{\frac{10}{{x}^{2}}} \]
    9. Step-by-step derivation
      1. unpow213.5%

        \[\leadsto \frac{10}{\color{blue}{x \cdot x}} \]
    10. Simplified13.5%

      \[\leadsto \color{blue}{\frac{10}{x \cdot x}} \]

    if 1 < (*.f64 x x)

    1. Initial program 86.8%

      \[\frac{10}{1 - x \cdot x} \]
    2. Step-by-step derivation
      1. sub-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      2. +-commutative86.8%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
      3. neg-sub086.8%

        \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
      4. associate-+l-86.8%

        \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
      5. sub0-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
      6. neg-mul-186.8%

        \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
      7. associate-/r*86.8%

        \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
      8. metadata-eval86.8%

        \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
      9. fma-neg99.7%

        \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
      10. metadata-eval99.7%

        \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
    3. Simplified99.7%

      \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
    4. Step-by-step derivation
      1. frac-2neg99.7%

        \[\leadsto \color{blue}{\frac{--10}{-\mathsf{fma}\left(x, x, -1\right)}} \]
      2. metadata-eval99.7%

        \[\leadsto \frac{\color{blue}{10}}{-\mathsf{fma}\left(x, x, -1\right)} \]
      3. fma-udef86.8%

        \[\leadsto \frac{10}{-\color{blue}{\left(x \cdot x + -1\right)}} \]
      4. distribute-neg-in86.8%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + \left(--1\right)}} \]
      5. metadata-eval86.8%

        \[\leadsto \frac{10}{\left(-x \cdot x\right) + \color{blue}{1}} \]
      6. +-commutative86.8%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      7. sub-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x}} \cdot \sqrt{\frac{10}{1 - x \cdot x}}} \]
      9. sqrt-unprod1.5%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}}} \]
      10. pow1/21.5%

        \[\leadsto \color{blue}{{\left(\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}\right)}^{0.5}} \]
      11. pow21.5%

        \[\leadsto {\color{blue}{\left({\left(\frac{10}{1 - x \cdot x}\right)}^{2}\right)}}^{0.5} \]
      12. metadata-eval1.5%

        \[\leadsto {\left({\left(\frac{\color{blue}{--10}}{1 - x \cdot x}\right)}^{2}\right)}^{0.5} \]
      13. sub-neg1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{1 + \left(-x \cdot x\right)}}\right)}^{2}\right)}^{0.5} \]
      14. +-commutative1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{\left(-x \cdot x\right) + 1}}\right)}^{2}\right)}^{0.5} \]
      15. metadata-eval1.5%

        \[\leadsto {\left({\left(\frac{--10}{\left(-x \cdot x\right) + \color{blue}{\left(--1\right)}}\right)}^{2}\right)}^{0.5} \]
      16. distribute-neg-in1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{-\left(x \cdot x + -1\right)}}\right)}^{2}\right)}^{0.5} \]
      17. fma-udef1.5%

        \[\leadsto {\left({\left(\frac{--10}{-\color{blue}{\mathsf{fma}\left(x, x, -1\right)}}\right)}^{2}\right)}^{0.5} \]
      18. frac-2neg1.5%

        \[\leadsto {\left({\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{2}\right)}^{0.5} \]
      19. pow21.5%

        \[\leadsto {\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \cdot \frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      20. frac-times1.5%

        \[\leadsto {\color{blue}{\left(\frac{-10 \cdot -10}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      21. metadata-eval1.5%

        \[\leadsto {\left(\frac{\color{blue}{100}}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}^{0.5} \]
      22. pow21.5%

        \[\leadsto {\left(\frac{100}{\color{blue}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}\right)}^{0.5} \]
    5. Applied egg-rr1.5%

      \[\leadsto \color{blue}{{\left(\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}\right)}^{0.5}} \]
    6. Step-by-step derivation
      1. unpow1/21.5%

        \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    7. Simplified1.5%

      \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    8. Taylor expanded in x around 0 13.5%

      \[\leadsto \color{blue}{-10} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification13.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot x \leq 1:\\ \;\;\;\;\frac{10}{x \cdot x}\\ \mathbf{else}:\\ \;\;\;\;-10\\ \end{array} \]

Alternative 3: 87.7% 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}
Derivation
  1. Initial program 87.7%

    \[\frac{10}{1 - x \cdot x} \]
  2. Final simplification87.7%

    \[\leadsto \frac{10}{1 - x \cdot x} \]

Alternative 4: 13.5% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \cdot x \leq 1:\\ \;\;\;\;10\\ \mathbf{else}:\\ \;\;\;\;-10\\ \end{array} \end{array} \]
(FPCore (x) :precision binary64 (if (<= (* x x) 1.0) 10.0 -10.0))
double code(double x) {
	double tmp;
	if ((x * x) <= 1.0) {
		tmp = 10.0;
	} else {
		tmp = -10.0;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if ((x * x) <= 1.0d0) then
        tmp = 10.0d0
    else
        tmp = -10.0d0
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if ((x * x) <= 1.0) {
		tmp = 10.0;
	} else {
		tmp = -10.0;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if (x * x) <= 1.0:
		tmp = 10.0
	else:
		tmp = -10.0
	return tmp
function code(x)
	tmp = 0.0
	if (Float64(x * x) <= 1.0)
		tmp = 10.0;
	else
		tmp = -10.0;
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if ((x * x) <= 1.0)
		tmp = 10.0;
	else
		tmp = -10.0;
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[N[(x * x), $MachinePrecision], 1.0], 10.0, -10.0]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \cdot x \leq 1:\\
\;\;\;\;10\\

\mathbf{else}:\\
\;\;\;\;-10\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 x x) < 1

    1. Initial program 88.3%

      \[\frac{10}{1 - x \cdot x} \]
    2. Step-by-step derivation
      1. sub-neg88.3%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      2. +-commutative88.3%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
      3. neg-sub088.3%

        \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
      4. associate-+l-88.3%

        \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
      5. sub0-neg88.3%

        \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
      6. neg-mul-188.3%

        \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
      7. associate-/r*88.3%

        \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
      8. metadata-eval88.3%

        \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
      9. fma-neg99.6%

        \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
      10. metadata-eval99.6%

        \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
    4. Taylor expanded in x around 0 13.5%

      \[\leadsto \color{blue}{10} \]

    if 1 < (*.f64 x x)

    1. Initial program 86.8%

      \[\frac{10}{1 - x \cdot x} \]
    2. Step-by-step derivation
      1. sub-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      2. +-commutative86.8%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
      3. neg-sub086.8%

        \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
      4. associate-+l-86.8%

        \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
      5. sub0-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
      6. neg-mul-186.8%

        \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
      7. associate-/r*86.8%

        \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
      8. metadata-eval86.8%

        \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
      9. fma-neg99.7%

        \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
      10. metadata-eval99.7%

        \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
    3. Simplified99.7%

      \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
    4. Step-by-step derivation
      1. frac-2neg99.7%

        \[\leadsto \color{blue}{\frac{--10}{-\mathsf{fma}\left(x, x, -1\right)}} \]
      2. metadata-eval99.7%

        \[\leadsto \frac{\color{blue}{10}}{-\mathsf{fma}\left(x, x, -1\right)} \]
      3. fma-udef86.8%

        \[\leadsto \frac{10}{-\color{blue}{\left(x \cdot x + -1\right)}} \]
      4. distribute-neg-in86.8%

        \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + \left(--1\right)}} \]
      5. metadata-eval86.8%

        \[\leadsto \frac{10}{\left(-x \cdot x\right) + \color{blue}{1}} \]
      6. +-commutative86.8%

        \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
      7. sub-neg86.8%

        \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x}} \cdot \sqrt{\frac{10}{1 - x \cdot x}}} \]
      9. sqrt-unprod1.5%

        \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}}} \]
      10. pow1/21.5%

        \[\leadsto \color{blue}{{\left(\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}\right)}^{0.5}} \]
      11. pow21.5%

        \[\leadsto {\color{blue}{\left({\left(\frac{10}{1 - x \cdot x}\right)}^{2}\right)}}^{0.5} \]
      12. metadata-eval1.5%

        \[\leadsto {\left({\left(\frac{\color{blue}{--10}}{1 - x \cdot x}\right)}^{2}\right)}^{0.5} \]
      13. sub-neg1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{1 + \left(-x \cdot x\right)}}\right)}^{2}\right)}^{0.5} \]
      14. +-commutative1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{\left(-x \cdot x\right) + 1}}\right)}^{2}\right)}^{0.5} \]
      15. metadata-eval1.5%

        \[\leadsto {\left({\left(\frac{--10}{\left(-x \cdot x\right) + \color{blue}{\left(--1\right)}}\right)}^{2}\right)}^{0.5} \]
      16. distribute-neg-in1.5%

        \[\leadsto {\left({\left(\frac{--10}{\color{blue}{-\left(x \cdot x + -1\right)}}\right)}^{2}\right)}^{0.5} \]
      17. fma-udef1.5%

        \[\leadsto {\left({\left(\frac{--10}{-\color{blue}{\mathsf{fma}\left(x, x, -1\right)}}\right)}^{2}\right)}^{0.5} \]
      18. frac-2neg1.5%

        \[\leadsto {\left({\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{2}\right)}^{0.5} \]
      19. pow21.5%

        \[\leadsto {\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \cdot \frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      20. frac-times1.5%

        \[\leadsto {\color{blue}{\left(\frac{-10 \cdot -10}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
      21. metadata-eval1.5%

        \[\leadsto {\left(\frac{\color{blue}{100}}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}^{0.5} \]
      22. pow21.5%

        \[\leadsto {\left(\frac{100}{\color{blue}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}\right)}^{0.5} \]
    5. Applied egg-rr1.5%

      \[\leadsto \color{blue}{{\left(\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}\right)}^{0.5}} \]
    6. Step-by-step derivation
      1. unpow1/21.5%

        \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    7. Simplified1.5%

      \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
    8. Taylor expanded in x around 0 13.5%

      \[\leadsto \color{blue}{-10} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification13.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot x \leq 1:\\ \;\;\;\;10\\ \mathbf{else}:\\ \;\;\;\;-10\\ \end{array} \]

Alternative 5: 5.6% accurate, 7.0× 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 87.7%

    \[\frac{10}{1 - x \cdot x} \]
  2. Step-by-step derivation
    1. sub-neg87.7%

      \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
    2. +-commutative87.7%

      \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + 1}} \]
    3. neg-sub087.7%

      \[\leadsto \frac{10}{\color{blue}{\left(0 - x \cdot x\right)} + 1} \]
    4. associate-+l-87.7%

      \[\leadsto \frac{10}{\color{blue}{0 - \left(x \cdot x - 1\right)}} \]
    5. sub0-neg87.7%

      \[\leadsto \frac{10}{\color{blue}{-\left(x \cdot x - 1\right)}} \]
    6. neg-mul-187.7%

      \[\leadsto \frac{10}{\color{blue}{-1 \cdot \left(x \cdot x - 1\right)}} \]
    7. associate-/r*87.7%

      \[\leadsto \color{blue}{\frac{\frac{10}{-1}}{x \cdot x - 1}} \]
    8. metadata-eval87.7%

      \[\leadsto \frac{\color{blue}{-10}}{x \cdot x - 1} \]
    9. fma-neg99.6%

      \[\leadsto \frac{-10}{\color{blue}{\mathsf{fma}\left(x, x, -1\right)}} \]
    10. metadata-eval99.6%

      \[\leadsto \frac{-10}{\mathsf{fma}\left(x, x, \color{blue}{-1}\right)} \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}} \]
  4. Step-by-step derivation
    1. frac-2neg99.6%

      \[\leadsto \color{blue}{\frac{--10}{-\mathsf{fma}\left(x, x, -1\right)}} \]
    2. metadata-eval99.6%

      \[\leadsto \frac{\color{blue}{10}}{-\mathsf{fma}\left(x, x, -1\right)} \]
    3. fma-udef87.7%

      \[\leadsto \frac{10}{-\color{blue}{\left(x \cdot x + -1\right)}} \]
    4. distribute-neg-in87.7%

      \[\leadsto \frac{10}{\color{blue}{\left(-x \cdot x\right) + \left(--1\right)}} \]
    5. metadata-eval87.7%

      \[\leadsto \frac{10}{\left(-x \cdot x\right) + \color{blue}{1}} \]
    6. +-commutative87.7%

      \[\leadsto \frac{10}{\color{blue}{1 + \left(-x \cdot x\right)}} \]
    7. sub-neg87.7%

      \[\leadsto \frac{10}{\color{blue}{1 - x \cdot x}} \]
    8. add-sqr-sqrt53.8%

      \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x}} \cdot \sqrt{\frac{10}{1 - x \cdot x}}} \]
    9. sqrt-unprod54.4%

      \[\leadsto \color{blue}{\sqrt{\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}}} \]
    10. pow1/254.4%

      \[\leadsto \color{blue}{{\left(\frac{10}{1 - x \cdot x} \cdot \frac{10}{1 - x \cdot x}\right)}^{0.5}} \]
    11. pow254.4%

      \[\leadsto {\color{blue}{\left({\left(\frac{10}{1 - x \cdot x}\right)}^{2}\right)}}^{0.5} \]
    12. metadata-eval54.4%

      \[\leadsto {\left({\left(\frac{\color{blue}{--10}}{1 - x \cdot x}\right)}^{2}\right)}^{0.5} \]
    13. sub-neg54.4%

      \[\leadsto {\left({\left(\frac{--10}{\color{blue}{1 + \left(-x \cdot x\right)}}\right)}^{2}\right)}^{0.5} \]
    14. +-commutative54.4%

      \[\leadsto {\left({\left(\frac{--10}{\color{blue}{\left(-x \cdot x\right) + 1}}\right)}^{2}\right)}^{0.5} \]
    15. metadata-eval54.4%

      \[\leadsto {\left({\left(\frac{--10}{\left(-x \cdot x\right) + \color{blue}{\left(--1\right)}}\right)}^{2}\right)}^{0.5} \]
    16. distribute-neg-in54.4%

      \[\leadsto {\left({\left(\frac{--10}{\color{blue}{-\left(x \cdot x + -1\right)}}\right)}^{2}\right)}^{0.5} \]
    17. fma-udef61.3%

      \[\leadsto {\left({\left(\frac{--10}{-\color{blue}{\mathsf{fma}\left(x, x, -1\right)}}\right)}^{2}\right)}^{0.5} \]
    18. frac-2neg61.3%

      \[\leadsto {\left({\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{2}\right)}^{0.5} \]
    19. pow261.3%

      \[\leadsto {\color{blue}{\left(\frac{-10}{\mathsf{fma}\left(x, x, -1\right)} \cdot \frac{-10}{\mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
    20. frac-times61.3%

      \[\leadsto {\color{blue}{\left(\frac{-10 \cdot -10}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}}^{0.5} \]
    21. metadata-eval61.3%

      \[\leadsto {\left(\frac{\color{blue}{100}}{\mathsf{fma}\left(x, x, -1\right) \cdot \mathsf{fma}\left(x, x, -1\right)}\right)}^{0.5} \]
    22. pow261.3%

      \[\leadsto {\left(\frac{100}{\color{blue}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}\right)}^{0.5} \]
  5. Applied egg-rr61.3%

    \[\leadsto \color{blue}{{\left(\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}\right)}^{0.5}} \]
  6. Step-by-step derivation
    1. unpow1/261.3%

      \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
  7. Simplified61.3%

    \[\leadsto \color{blue}{\sqrt{\frac{100}{{\left(\mathsf{fma}\left(x, x, -1\right)\right)}^{2}}}} \]
  8. Taylor expanded in x around 0 6.2%

    \[\leadsto \color{blue}{-10} \]
  9. Final simplification6.2%

    \[\leadsto -10 \]

Reproduce

?
herbie shell --seed 2023207 
(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))))