Given's Rotation SVD example

Percentage Accurate: 79.1% → 99.9%
Time: 10.6s
Alternatives: 6
Speedup: 0.7×

Specification

?
\[10^{-150} < \left|x\right| \land \left|x\right| < 10^{+150}\]
\[\begin{array}{l} \\ \sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \end{array} \]
(FPCore (p x)
 :precision binary64
 (sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))
double code(double p, double x) {
	return sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
}
real(8) function code(p, x)
    real(8), intent (in) :: p
    real(8), intent (in) :: x
    code = sqrt((0.5d0 * (1.0d0 + (x / sqrt((((4.0d0 * p) * p) + (x * x)))))))
end function
public static double code(double p, double x) {
	return Math.sqrt((0.5 * (1.0 + (x / Math.sqrt((((4.0 * p) * p) + (x * x)))))));
}
def code(p, x):
	return math.sqrt((0.5 * (1.0 + (x / math.sqrt((((4.0 * p) * p) + (x * x)))))))
function code(p, x)
	return sqrt(Float64(0.5 * Float64(1.0 + Float64(x / sqrt(Float64(Float64(Float64(4.0 * p) * p) + Float64(x * x)))))))
end
function tmp = code(p, x)
	tmp = sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
end
code[p_, x_] := N[Sqrt[N[(0.5 * N[(1.0 + N[(x / N[Sqrt[N[(N[(N[(4.0 * p), $MachinePrecision] * p), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)}
\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 6 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: 79.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \end{array} \]
(FPCore (p x)
 :precision binary64
 (sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))
double code(double p, double x) {
	return sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
}
real(8) function code(p, x)
    real(8), intent (in) :: p
    real(8), intent (in) :: x
    code = sqrt((0.5d0 * (1.0d0 + (x / sqrt((((4.0d0 * p) * p) + (x * x)))))))
end function
public static double code(double p, double x) {
	return Math.sqrt((0.5 * (1.0 + (x / Math.sqrt((((4.0 * p) * p) + (x * x)))))));
}
def code(p, x):
	return math.sqrt((0.5 * (1.0 + (x / math.sqrt((((4.0 * p) * p) + (x * x)))))))
function code(p, x)
	return sqrt(Float64(0.5 * Float64(1.0 + Float64(x / sqrt(Float64(Float64(Float64(4.0 * p) * p) + Float64(x * x)))))))
end
function tmp = code(p, x)
	tmp = sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
end
code[p_, x_] := N[Sqrt[N[(0.5 * N[(1.0 + N[(x / N[Sqrt[N[(N[(N[(4.0 * p), $MachinePrecision] * p), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)}
\end{array}

Alternative 1: 99.9% accurate, 0.3× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ \begin{array}{l} t_0 := \mathsf{hypot}\left(x, p\_m \cdot 2\right)\\ \mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.999999998:\\ \;\;\;\;\frac{p\_m}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{t\_0}} \cdot \sqrt{\mathsf{fma}\left(x, \frac{0.5}{t\_0}, 0.5\right)}\right)}\\ \end{array} \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x)
 :precision binary64
 (let* ((t_0 (hypot x (* p_m 2.0))))
   (if (<= (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))) -0.999999998)
     (/ p_m (- x))
     (sqrt
      (*
       (sqrt 0.5)
       (* (sqrt (+ 1.0 (/ x t_0))) (sqrt (fma x (/ 0.5 t_0) 0.5))))))))
p_m = fabs(p);
double code(double p_m, double x) {
	double t_0 = hypot(x, (p_m * 2.0));
	double tmp;
	if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.999999998) {
		tmp = p_m / -x;
	} else {
		tmp = sqrt((sqrt(0.5) * (sqrt((1.0 + (x / t_0))) * sqrt(fma(x, (0.5 / t_0), 0.5)))));
	}
	return tmp;
}
p_m = abs(p)
function code(p_m, x)
	t_0 = hypot(x, Float64(p_m * 2.0))
	tmp = 0.0
	if (Float64(x / sqrt(Float64(Float64(p_m * Float64(4.0 * p_m)) + Float64(x * x)))) <= -0.999999998)
		tmp = Float64(p_m / Float64(-x));
	else
		tmp = sqrt(Float64(sqrt(0.5) * Float64(sqrt(Float64(1.0 + Float64(x / t_0))) * sqrt(fma(x, Float64(0.5 / t_0), 0.5)))));
	end
	return tmp
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := Block[{t$95$0 = N[Sqrt[x ^ 2 + N[(p$95$m * 2.0), $MachinePrecision] ^ 2], $MachinePrecision]}, If[LessEqual[N[(x / N[Sqrt[N[(N[(p$95$m * N[(4.0 * p$95$m), $MachinePrecision]), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], -0.999999998], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[N[(N[Sqrt[0.5], $MachinePrecision] * N[(N[Sqrt[N[(1.0 + N[(x / t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(x * N[(0.5 / t$95$0), $MachinePrecision] + 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}
p_m = \left|p\right|

\\
\begin{array}{l}
t_0 := \mathsf{hypot}\left(x, p\_m \cdot 2\right)\\
\mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.999999998:\\
\;\;\;\;\frac{p\_m}{-x}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{t\_0}} \cdot \sqrt{\mathsf{fma}\left(x, \frac{0.5}{t\_0}, 0.5\right)}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) < -0.999999997999999946

    1. Initial program 14.6%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative14.6%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*14.6%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative14.6%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified14.6%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around -inf 62.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{p}{x}} \]
    6. Step-by-step derivation
      1. mul-1-neg62.2%

        \[\leadsto \color{blue}{-\frac{p}{x}} \]
      2. distribute-neg-frac262.2%

        \[\leadsto \color{blue}{\frac{p}{-x}} \]
    7. Simplified62.2%

      \[\leadsto \color{blue}{\frac{p}{-x}} \]

    if -0.999999997999999946 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x))))

    1. Initial program 99.8%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*99.8%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative99.8%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified99.8%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Applied egg-rr99.8%

      \[\leadsto \sqrt{\color{blue}{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)}\right)}} \]
    6. Step-by-step derivation
      1. fma-undefine99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\color{blue}{\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot 0.5 + 0.5}}\right)} \]
      2. metadata-eval99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot \color{blue}{\frac{0.5}{1}} + 0.5}\right)} \]
      3. times-frac99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\color{blue}{\frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p \cdot 2\right) \cdot 1}} + 0.5}\right)} \]
      4. *-rgt-identity99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\frac{x \cdot 0.5}{\color{blue}{\mathsf{hypot}\left(x, p \cdot 2\right)}} + 0.5}\right)} \]
      5. associate-/l*99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\color{blue}{x \cdot \frac{0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}} + 0.5}\right)} \]
      6. fma-define99.8%

        \[\leadsto \sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\color{blue}{\mathsf{fma}\left(x, \frac{0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5\right)}}\right)} \]
    7. Simplified99.8%

      \[\leadsto \sqrt{\color{blue}{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\mathsf{fma}\left(x, \frac{0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5\right)}\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification92.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{\sqrt{p \cdot \left(4 \cdot p\right) + x \cdot x}} \leq -0.999999998:\\ \;\;\;\;\frac{p}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\sqrt{0.5} \cdot \left(\sqrt{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot \sqrt{\mathsf{fma}\left(x, \frac{0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5\right)}\right)}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.8% accurate, 0.4× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ \begin{array}{l} \mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.998:\\ \;\;\;\;\frac{p\_m}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, p\_m \cdot 2\right)}}\right)}\\ \end{array} \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x)
 :precision binary64
 (if (<= (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))) -0.998)
   (/ p_m (- x))
   (sqrt (* 0.5 (log (exp (+ 1.0 (/ x (hypot x (* p_m 2.0))))))))))
p_m = fabs(p);
double code(double p_m, double x) {
	double tmp;
	if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998) {
		tmp = p_m / -x;
	} else {
		tmp = sqrt((0.5 * log(exp((1.0 + (x / hypot(x, (p_m * 2.0))))))));
	}
	return tmp;
}
p_m = Math.abs(p);
public static double code(double p_m, double x) {
	double tmp;
	if ((x / Math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998) {
		tmp = p_m / -x;
	} else {
		tmp = Math.sqrt((0.5 * Math.log(Math.exp((1.0 + (x / Math.hypot(x, (p_m * 2.0))))))));
	}
	return tmp;
}
p_m = math.fabs(p)
def code(p_m, x):
	tmp = 0
	if (x / math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998:
		tmp = p_m / -x
	else:
		tmp = math.sqrt((0.5 * math.log(math.exp((1.0 + (x / math.hypot(x, (p_m * 2.0))))))))
	return tmp
p_m = abs(p)
function code(p_m, x)
	tmp = 0.0
	if (Float64(x / sqrt(Float64(Float64(p_m * Float64(4.0 * p_m)) + Float64(x * x)))) <= -0.998)
		tmp = Float64(p_m / Float64(-x));
	else
		tmp = sqrt(Float64(0.5 * log(exp(Float64(1.0 + Float64(x / hypot(x, Float64(p_m * 2.0))))))));
	end
	return tmp
end
p_m = abs(p);
function tmp_2 = code(p_m, x)
	tmp = 0.0;
	if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998)
		tmp = p_m / -x;
	else
		tmp = sqrt((0.5 * log(exp((1.0 + (x / hypot(x, (p_m * 2.0))))))));
	end
	tmp_2 = tmp;
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := If[LessEqual[N[(x / N[Sqrt[N[(N[(p$95$m * N[(4.0 * p$95$m), $MachinePrecision]), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], -0.998], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[N[(0.5 * N[Log[N[Exp[N[(1.0 + N[(x / N[Sqrt[x ^ 2 + N[(p$95$m * 2.0), $MachinePrecision] ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
p_m = \left|p\right|

\\
\begin{array}{l}
\mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.998:\\
\;\;\;\;\frac{p\_m}{-x}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, p\_m \cdot 2\right)}}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) < -0.998

    1. Initial program 15.4%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative15.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative15.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified15.4%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around -inf 61.1%

      \[\leadsto \color{blue}{-1 \cdot \frac{p}{x}} \]
    6. Step-by-step derivation
      1. mul-1-neg61.1%

        \[\leadsto \color{blue}{-\frac{p}{x}} \]
      2. distribute-neg-frac261.1%

        \[\leadsto \color{blue}{\frac{p}{-x}} \]
    7. Simplified61.1%

      \[\leadsto \color{blue}{\frac{p}{-x}} \]

    if -0.998 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x))))

    1. Initial program 100.0%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. add-log-exp100.0%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\log \left(e^{1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}}\right)}} \]
      2. +-commutative100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{\color{blue}{x \cdot x + \left(4 \cdot p\right) \cdot p}}}}\right)} \]
      3. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{x \cdot x + \color{blue}{4 \cdot \left(p \cdot p\right)}}}}\right)} \]
      4. fma-undefine100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}}\right)} \]
      5. fma-undefine100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{\color{blue}{x \cdot x + 4 \cdot \left(p \cdot p\right)}}}}\right)} \]
      6. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{x \cdot x + \color{blue}{\left(4 \cdot p\right) \cdot p}}}}\right)} \]
      7. add-sqr-sqrt100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\sqrt{x \cdot x + \color{blue}{\sqrt{\left(4 \cdot p\right) \cdot p} \cdot \sqrt{\left(4 \cdot p\right) \cdot p}}}}}\right)} \]
      8. hypot-define100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\color{blue}{\mathsf{hypot}\left(x, \sqrt{\left(4 \cdot p\right) \cdot p}\right)}}}\right)} \]
      9. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, \sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)}}\right)}}\right)} \]
      10. *-commutative100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, \sqrt{\color{blue}{\left(p \cdot p\right) \cdot 4}}\right)}}\right)} \]
      11. sqrt-prod100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, \color{blue}{\sqrt{p \cdot p} \cdot \sqrt{4}}\right)}}\right)} \]
      12. sqrt-prod50.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, \color{blue}{\left(\sqrt{p} \cdot \sqrt{p}\right)} \cdot \sqrt{4}\right)}}\right)} \]
      13. add-sqr-sqrt100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, \color{blue}{p} \cdot \sqrt{4}\right)}}\right)} \]
      14. metadata-eval100.0%

        \[\leadsto \sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot \color{blue}{2}\right)}}\right)} \]
    4. Applied egg-rr100.0%

      \[\leadsto \sqrt{0.5 \cdot \color{blue}{\log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}}\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification91.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{\sqrt{p \cdot \left(4 \cdot p\right) + x \cdot x}} \leq -0.998:\\ \;\;\;\;\frac{p}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5 \cdot \log \left(e^{1 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}}\right)}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.8% accurate, 0.7× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ \begin{array}{l} \mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.998:\\ \;\;\;\;\frac{p\_m}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5 + \frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p\_m \cdot 2\right)}}\\ \end{array} \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x)
 :precision binary64
 (if (<= (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))) -0.998)
   (/ p_m (- x))
   (sqrt (+ 0.5 (/ (* x 0.5) (hypot x (* p_m 2.0)))))))
p_m = fabs(p);
double code(double p_m, double x) {
	double tmp;
	if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998) {
		tmp = p_m / -x;
	} else {
		tmp = sqrt((0.5 + ((x * 0.5) / hypot(x, (p_m * 2.0)))));
	}
	return tmp;
}
p_m = Math.abs(p);
public static double code(double p_m, double x) {
	double tmp;
	if ((x / Math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998) {
		tmp = p_m / -x;
	} else {
		tmp = Math.sqrt((0.5 + ((x * 0.5) / Math.hypot(x, (p_m * 2.0)))));
	}
	return tmp;
}
p_m = math.fabs(p)
def code(p_m, x):
	tmp = 0
	if (x / math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998:
		tmp = p_m / -x
	else:
		tmp = math.sqrt((0.5 + ((x * 0.5) / math.hypot(x, (p_m * 2.0)))))
	return tmp
p_m = abs(p)
function code(p_m, x)
	tmp = 0.0
	if (Float64(x / sqrt(Float64(Float64(p_m * Float64(4.0 * p_m)) + Float64(x * x)))) <= -0.998)
		tmp = Float64(p_m / Float64(-x));
	else
		tmp = sqrt(Float64(0.5 + Float64(Float64(x * 0.5) / hypot(x, Float64(p_m * 2.0)))));
	end
	return tmp
end
p_m = abs(p);
function tmp_2 = code(p_m, x)
	tmp = 0.0;
	if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.998)
		tmp = p_m / -x;
	else
		tmp = sqrt((0.5 + ((x * 0.5) / hypot(x, (p_m * 2.0)))));
	end
	tmp_2 = tmp;
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := If[LessEqual[N[(x / N[Sqrt[N[(N[(p$95$m * N[(4.0 * p$95$m), $MachinePrecision]), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], -0.998], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[N[(0.5 + N[(N[(x * 0.5), $MachinePrecision] / N[Sqrt[x ^ 2 + N[(p$95$m * 2.0), $MachinePrecision] ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
p_m = \left|p\right|

\\
\begin{array}{l}
\mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.998:\\
\;\;\;\;\frac{p\_m}{-x}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{0.5 + \frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p\_m \cdot 2\right)}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) < -0.998

    1. Initial program 15.4%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative15.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*15.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative15.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified15.4%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around -inf 61.1%

      \[\leadsto \color{blue}{-1 \cdot \frac{p}{x}} \]
    6. Step-by-step derivation
      1. mul-1-neg61.1%

        \[\leadsto \color{blue}{-\frac{p}{x}} \]
      2. distribute-neg-frac261.1%

        \[\leadsto \color{blue}{\frac{p}{-x}} \]
    7. Simplified61.1%

      \[\leadsto \color{blue}{\frac{p}{-x}} \]

    if -0.998 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x))))

    1. Initial program 100.0%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*100.0%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative100.0%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. associate-*r/100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\frac{0.5 \cdot x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
      2. clear-num100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\frac{1}{\frac{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}{0.5 \cdot x}}}} \]
      3. fma-undefine100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\sqrt{\color{blue}{x \cdot x + 4 \cdot \left(p \cdot p\right)}}}{0.5 \cdot x}}} \]
      4. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\sqrt{x \cdot x + \color{blue}{\left(4 \cdot p\right) \cdot p}}}{0.5 \cdot x}}} \]
      5. add-sqr-sqrt100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\sqrt{x \cdot x + \color{blue}{\sqrt{\left(4 \cdot p\right) \cdot p} \cdot \sqrt{\left(4 \cdot p\right) \cdot p}}}}{0.5 \cdot x}}} \]
      6. hypot-define100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\color{blue}{\mathsf{hypot}\left(x, \sqrt{\left(4 \cdot p\right) \cdot p}\right)}}{0.5 \cdot x}}} \]
      7. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, \sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)}}\right)}{0.5 \cdot x}}} \]
      8. *-commutative100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, \sqrt{\color{blue}{\left(p \cdot p\right) \cdot 4}}\right)}{0.5 \cdot x}}} \]
      9. sqrt-prod100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, \color{blue}{\sqrt{p \cdot p} \cdot \sqrt{4}}\right)}{0.5 \cdot x}}} \]
      10. sqrt-prod50.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, \color{blue}{\left(\sqrt{p} \cdot \sqrt{p}\right)} \cdot \sqrt{4}\right)}{0.5 \cdot x}}} \]
      11. add-sqr-sqrt100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, \color{blue}{p} \cdot \sqrt{4}\right)}{0.5 \cdot x}}} \]
      12. metadata-eval100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, p \cdot \color{blue}{2}\right)}{0.5 \cdot x}}} \]
      13. *-commutative100.0%

        \[\leadsto \sqrt{0.5 + \frac{1}{\frac{\mathsf{hypot}\left(x, p \cdot 2\right)}{\color{blue}{x \cdot 0.5}}}} \]
    6. Applied egg-rr100.0%

      \[\leadsto \sqrt{0.5 + \color{blue}{\frac{1}{\frac{\mathsf{hypot}\left(x, p \cdot 2\right)}{x \cdot 0.5}}}} \]
    7. Step-by-step derivation
      1. associate-/r/100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\frac{1}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot \left(x \cdot 0.5\right)}} \]
      2. associate-*r*100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\left(\frac{1}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot x\right) \cdot 0.5}} \]
      3. associate-*l/100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\frac{1 \cdot x}{\mathsf{hypot}\left(x, p \cdot 2\right)}} \cdot 0.5} \]
      4. *-lft-identity100.0%

        \[\leadsto \sqrt{0.5 + \frac{\color{blue}{x}}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot 0.5} \]
      5. metadata-eval100.0%

        \[\leadsto \sqrt{0.5 + \frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)} \cdot \color{blue}{\frac{0.5}{1}}} \]
      6. times-frac100.0%

        \[\leadsto \sqrt{0.5 + \color{blue}{\frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p \cdot 2\right) \cdot 1}}} \]
      7. *-rgt-identity100.0%

        \[\leadsto \sqrt{0.5 + \frac{x \cdot 0.5}{\color{blue}{\mathsf{hypot}\left(x, p \cdot 2\right)}}} \]
    8. Simplified100.0%

      \[\leadsto \sqrt{0.5 + \color{blue}{\frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification91.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x}{\sqrt{p \cdot \left(4 \cdot p\right) + x \cdot x}} \leq -0.998:\\ \;\;\;\;\frac{p}{-x}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5 + \frac{x \cdot 0.5}{\mathsf{hypot}\left(x, p \cdot 2\right)}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 68.9% accurate, 2.0× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ \begin{array}{l} \mathbf{if}\;p\_m \leq 2.45 \cdot 10^{-45}:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5}\\ \end{array} \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x) :precision binary64 (if (<= p_m 2.45e-45) 1.0 (sqrt 0.5)))
p_m = fabs(p);
double code(double p_m, double x) {
	double tmp;
	if (p_m <= 2.45e-45) {
		tmp = 1.0;
	} else {
		tmp = sqrt(0.5);
	}
	return tmp;
}
p_m = abs(p)
real(8) function code(p_m, x)
    real(8), intent (in) :: p_m
    real(8), intent (in) :: x
    real(8) :: tmp
    if (p_m <= 2.45d-45) then
        tmp = 1.0d0
    else
        tmp = sqrt(0.5d0)
    end if
    code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
	double tmp;
	if (p_m <= 2.45e-45) {
		tmp = 1.0;
	} else {
		tmp = Math.sqrt(0.5);
	}
	return tmp;
}
p_m = math.fabs(p)
def code(p_m, x):
	tmp = 0
	if p_m <= 2.45e-45:
		tmp = 1.0
	else:
		tmp = math.sqrt(0.5)
	return tmp
p_m = abs(p)
function code(p_m, x)
	tmp = 0.0
	if (p_m <= 2.45e-45)
		tmp = 1.0;
	else
		tmp = sqrt(0.5);
	end
	return tmp
end
p_m = abs(p);
function tmp_2 = code(p_m, x)
	tmp = 0.0;
	if (p_m <= 2.45e-45)
		tmp = 1.0;
	else
		tmp = sqrt(0.5);
	end
	tmp_2 = tmp;
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := If[LessEqual[p$95$m, 2.45e-45], 1.0, N[Sqrt[0.5], $MachinePrecision]]
\begin{array}{l}
p_m = \left|p\right|

\\
\begin{array}{l}
\mathbf{if}\;p\_m \leq 2.45 \cdot 10^{-45}:\\
\;\;\;\;1\\

\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if p < 2.4499999999999999e-45

    1. Initial program 78.1%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Add Preprocessing
    3. Applied egg-rr78.0%

      \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}\right)}^{0.3333333333333333}} \]
    4. Step-by-step derivation
      1. unpow1/378.0%

        \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
    5. Simplified78.0%

      \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
    6. Taylor expanded in x around inf 45.9%

      \[\leadsto \color{blue}{1} \]

    if 2.4499999999999999e-45 < p

    1. Initial program 90.9%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 88.0%

      \[\leadsto \color{blue}{\sqrt{0.5}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 5: 55.8% accurate, 23.8× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ \begin{array}{l} \mathbf{if}\;x \leq -9 \cdot 10^{-149}:\\ \;\;\;\;\frac{p\_m}{-x}\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x) :precision binary64 (if (<= x -9e-149) (/ p_m (- x)) 1.0))
p_m = fabs(p);
double code(double p_m, double x) {
	double tmp;
	if (x <= -9e-149) {
		tmp = p_m / -x;
	} else {
		tmp = 1.0;
	}
	return tmp;
}
p_m = abs(p)
real(8) function code(p_m, x)
    real(8), intent (in) :: p_m
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-9d-149)) then
        tmp = p_m / -x
    else
        tmp = 1.0d0
    end if
    code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
	double tmp;
	if (x <= -9e-149) {
		tmp = p_m / -x;
	} else {
		tmp = 1.0;
	}
	return tmp;
}
p_m = math.fabs(p)
def code(p_m, x):
	tmp = 0
	if x <= -9e-149:
		tmp = p_m / -x
	else:
		tmp = 1.0
	return tmp
p_m = abs(p)
function code(p_m, x)
	tmp = 0.0
	if (x <= -9e-149)
		tmp = Float64(p_m / Float64(-x));
	else
		tmp = 1.0;
	end
	return tmp
end
p_m = abs(p);
function tmp_2 = code(p_m, x)
	tmp = 0.0;
	if (x <= -9e-149)
		tmp = p_m / -x;
	else
		tmp = 1.0;
	end
	tmp_2 = tmp;
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := If[LessEqual[x, -9e-149], N[(p$95$m / (-x)), $MachinePrecision], 1.0]
\begin{array}{l}
p_m = \left|p\right|

\\
\begin{array}{l}
\mathbf{if}\;x \leq -9 \cdot 10^{-149}:\\
\;\;\;\;\frac{p\_m}{-x}\\

\mathbf{else}:\\
\;\;\;\;1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -8.9999999999999996e-149

    1. Initial program 63.4%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Step-by-step derivation
      1. +-commutative63.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}} + 1\right)}} \]
      2. sqr-neg63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + \color{blue}{\left(-x\right) \cdot \left(-x\right)}}} + 1\right)} \]
      3. associate-*l*63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(p \cdot p\right)} + \left(-x\right) \cdot \left(-x\right)}} + 1\right)} \]
      4. sqr-neg63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{4 \cdot \left(p \cdot p\right) + \color{blue}{x \cdot x}}} + 1\right)} \]
      5. fma-define63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\mathsf{fma}\left(4, p \cdot p, x \cdot x\right)}}} + 1\right)} \]
      6. sqr-neg63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\mathsf{fma}\left(4, \color{blue}{\left(-p\right) \cdot \left(-p\right)}, x \cdot x\right)}} + 1\right)} \]
      7. fma-define63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{4 \cdot \left(\left(-p\right) \cdot \left(-p\right)\right) + x \cdot x}}} + 1\right)} \]
      8. associate-*l*63.4%

        \[\leadsto \sqrt{0.5 \cdot \left(\frac{x}{\sqrt{\color{blue}{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right)} + x \cdot x}} + 1\right)} \]
      9. +-commutative63.4%

        \[\leadsto \sqrt{0.5 \cdot \color{blue}{\left(1 + \frac{x}{\sqrt{\left(4 \cdot \left(-p\right)\right) \cdot \left(-p\right) + x \cdot x}}\right)}} \]
    3. Simplified63.4%

      \[\leadsto \color{blue}{\sqrt{0.5 + 0.5 \cdot \frac{x}{\sqrt{\mathsf{fma}\left(x, x, 4 \cdot \left(p \cdot p\right)\right)}}}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around -inf 28.4%

      \[\leadsto \color{blue}{-1 \cdot \frac{p}{x}} \]
    6. Step-by-step derivation
      1. mul-1-neg28.4%

        \[\leadsto \color{blue}{-\frac{p}{x}} \]
      2. distribute-neg-frac228.4%

        \[\leadsto \color{blue}{\frac{p}{-x}} \]
    7. Simplified28.4%

      \[\leadsto \color{blue}{\frac{p}{-x}} \]

    if -8.9999999999999996e-149 < x

    1. Initial program 100.0%

      \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
    2. Add Preprocessing
    3. Applied egg-rr100.0%

      \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}\right)}^{0.3333333333333333}} \]
    4. Step-by-step derivation
      1. unpow1/3100.0%

        \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
    6. Taylor expanded in x around inf 61.4%

      \[\leadsto \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 35.7% accurate, 215.0× speedup?

\[\begin{array}{l} p_m = \left|p\right| \\ 1 \end{array} \]
p_m = (fabs.f64 p)
(FPCore (p_m x) :precision binary64 1.0)
p_m = fabs(p);
double code(double p_m, double x) {
	return 1.0;
}
p_m = abs(p)
real(8) function code(p_m, x)
    real(8), intent (in) :: p_m
    real(8), intent (in) :: x
    code = 1.0d0
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
	return 1.0;
}
p_m = math.fabs(p)
def code(p_m, x):
	return 1.0
p_m = abs(p)
function code(p_m, x)
	return 1.0
end
p_m = abs(p);
function tmp = code(p_m, x)
	tmp = 1.0;
end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := 1.0
\begin{array}{l}
p_m = \left|p\right|

\\
1
\end{array}
Derivation
  1. Initial program 82.1%

    \[\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)} \]
  2. Add Preprocessing
  3. Applied egg-rr82.1%

    \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}\right)}^{0.3333333333333333}} \]
  4. Step-by-step derivation
    1. unpow1/382.1%

      \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
  5. Simplified82.1%

    \[\leadsto \color{blue}{\sqrt[3]{{\left(\mathsf{fma}\left(\frac{x}{\mathsf{hypot}\left(x, p \cdot 2\right)}, 0.5, 0.5\right)\right)}^{1.5}}} \]
  6. Taylor expanded in x around inf 38.2%

    \[\leadsto \color{blue}{1} \]
  7. Add Preprocessing

Developer Target 1: 79.1% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \sqrt{0.5 + \frac{\mathsf{copysign}\left(0.5, x\right)}{\mathsf{hypot}\left(1, \frac{2 \cdot p}{x}\right)}} \end{array} \]
(FPCore (p x)
 :precision binary64
 (sqrt (+ 0.5 (/ (copysign 0.5 x) (hypot 1.0 (/ (* 2.0 p) x))))))
double code(double p, double x) {
	return sqrt((0.5 + (copysign(0.5, x) / hypot(1.0, ((2.0 * p) / x)))));
}
public static double code(double p, double x) {
	return Math.sqrt((0.5 + (Math.copySign(0.5, x) / Math.hypot(1.0, ((2.0 * p) / x)))));
}
def code(p, x):
	return math.sqrt((0.5 + (math.copysign(0.5, x) / math.hypot(1.0, ((2.0 * p) / x)))))
function code(p, x)
	return sqrt(Float64(0.5 + Float64(copysign(0.5, x) / hypot(1.0, Float64(Float64(2.0 * p) / x)))))
end
function tmp = code(p, x)
	tmp = sqrt((0.5 + ((sign(x) * abs(0.5)) / hypot(1.0, ((2.0 * p) / x)))));
end
code[p_, x_] := N[Sqrt[N[(0.5 + N[(N[With[{TMP1 = Abs[0.5], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision] / N[Sqrt[1.0 ^ 2 + N[(N[(2.0 * p), $MachinePrecision] / x), $MachinePrecision] ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{0.5 + \frac{\mathsf{copysign}\left(0.5, x\right)}{\mathsf{hypot}\left(1, \frac{2 \cdot p}{x}\right)}}
\end{array}

Reproduce

?
herbie shell --seed 2024144 
(FPCore (p x)
  :name "Given's Rotation SVD example"
  :precision binary64
  :pre (and (< 1e-150 (fabs x)) (< (fabs x) 1e+150))

  :alt
  (! :herbie-platform default (sqrt (+ 1/2 (/ (copysign 1/2 x) (hypot 1 (/ (* 2 p) x))))))

  (sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))