Given's Rotation SVD example, simplified

Percentage Accurate: 76.0% → 99.9%
Time: 11.5s
Alternatives: 15
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ 1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \end{array} \]
(FPCore (x)
 :precision binary64
 (- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))
double code(double x) {
	return 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
}
public static double code(double x) {
	return 1.0 - Math.sqrt((0.5 * (1.0 + (1.0 / Math.hypot(1.0, x)))));
}
def code(x):
	return 1.0 - math.sqrt((0.5 * (1.0 + (1.0 / math.hypot(1.0, x)))))
function code(x)
	return Float64(1.0 - sqrt(Float64(0.5 * Float64(1.0 + Float64(1.0 / hypot(1.0, x))))))
end
function tmp = code(x)
	tmp = 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
end
code[x_] := N[(1.0 - N[Sqrt[N[(0.5 * N[(1.0 + N[(1.0 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\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 15 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 76.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \end{array} \]
(FPCore (x)
 :precision binary64
 (- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))
double code(double x) {
	return 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
}
public static double code(double x) {
	return 1.0 - Math.sqrt((0.5 * (1.0 + (1.0 / Math.hypot(1.0, x)))));
}
def code(x):
	return 1.0 - math.sqrt((0.5 * (1.0 + (1.0 / math.hypot(1.0, x)))))
function code(x)
	return Float64(1.0 - sqrt(Float64(0.5 * Float64(1.0 + Float64(1.0 / hypot(1.0, x))))))
end
function tmp = code(x)
	tmp = 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
end
code[x_] := N[(1.0 - N[Sqrt[N[(0.5 * N[(1.0 + N[(1.0 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

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

Alternative 1: 99.9% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}\\ \mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 1.005:\\ \;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}}{1 + \sqrt{t\_0}}}{t\_0}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (+ 0.5 (/ 0.5 (sqrt (fma x x 1.0))))))
   (if (<= (hypot 1.0 x) 1.005)
     (*
      (* x x)
      (fma
       (* x x)
       (fma (* x x) (fma (* x x) -0.056243896484375 0.0673828125) -0.0859375)
       0.125))
     (/ (/ (- 0.25 (/ 0.25 (fma x x 1.0))) (+ 1.0 (sqrt t_0))) t_0))))
double code(double x) {
	double t_0 = 0.5 + (0.5 / sqrt(fma(x, x, 1.0)));
	double tmp;
	if (hypot(1.0, x) <= 1.005) {
		tmp = (x * x) * fma((x * x), fma((x * x), fma((x * x), -0.056243896484375, 0.0673828125), -0.0859375), 0.125);
	} else {
		tmp = ((0.25 - (0.25 / fma(x, x, 1.0))) / (1.0 + sqrt(t_0))) / t_0;
	}
	return tmp;
}
function code(x)
	t_0 = Float64(0.5 + Float64(0.5 / sqrt(fma(x, x, 1.0))))
	tmp = 0.0
	if (hypot(1.0, x) <= 1.005)
		tmp = Float64(Float64(x * x) * fma(Float64(x * x), fma(Float64(x * x), fma(Float64(x * x), -0.056243896484375, 0.0673828125), -0.0859375), 0.125));
	else
		tmp = Float64(Float64(Float64(0.25 - Float64(0.25 / fma(x, x, 1.0))) / Float64(1.0 + sqrt(t_0))) / t_0);
	end
	return tmp
end
code[x_] := Block[{t$95$0 = N[(0.5 + N[(0.5 / N[Sqrt[N[(x * x + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 1.005], N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * -0.056243896484375 + 0.0673828125), $MachinePrecision] + -0.0859375), $MachinePrecision] + 0.125), $MachinePrecision]), $MachinePrecision], N[(N[(N[(0.25 - N[(0.25 / N[(x * x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[Sqrt[t$95$0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}\\
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 1.005:\\
\;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{\frac{0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}}{1 + \sqrt{t\_0}}}{t\_0}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (hypot.f64 #s(literal 1 binary64) x) < 1.0049999999999999

    1. Initial program 54.3%

      \[1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \]
    2. Add Preprocessing
    3. Applied rewrites54.4%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}} + -0.5}{-1 + \left(-\sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}\right)}} \]
    4. Taylor expanded in x around 0

      \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right)} \]
    5. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right)} \]
      2. unpow2N/A

        \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right) \]
      3. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right) \]
      4. +-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right) + \frac{1}{8}\right)} \]
      5. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\mathsf{fma}\left({x}^{2}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right)} \]
      6. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(\color{blue}{x \cdot x}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right) \]
      7. lower-*.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(\color{blue}{x \cdot x}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right) \]
      8. sub-negN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \color{blue}{{x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) + \left(\mathsf{neg}\left(\frac{11}{128}\right)\right)}, \frac{1}{8}\right) \]
      9. metadata-evalN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) + \color{blue}{\frac{-11}{128}}, \frac{1}{8}\right) \]
      10. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right)}, \frac{1}{8}\right) \]
      11. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      12. lower-*.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      13. +-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{\frac{-1843}{32768} \cdot {x}^{2} + \frac{69}{1024}}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      14. *-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{{x}^{2} \cdot \frac{-1843}{32768}} + \frac{69}{1024}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      15. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{-1843}{32768}, \frac{69}{1024}\right)}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      16. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{-1843}{32768}, \frac{69}{1024}\right), \frac{-11}{128}\right), \frac{1}{8}\right) \]
      17. lower-*.f64100.0

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right) \]
    6. Applied rewrites100.0%

      \[\leadsto \color{blue}{\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)} \]

    if 1.0049999999999999 < (hypot.f64 #s(literal 1 binary64) x)

    1. Initial program 98.4%

      \[1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \]
    2. Add Preprocessing
    3. Applied rewrites99.8%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}} + -0.5}{-1 + \left(-\sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}\right)}} \]
    4. Applied rewrites99.9%

      \[\leadsto \color{blue}{\frac{\left(\frac{0.25}{\mathsf{fma}\left(x, x, 1\right)} + -0.25\right) \cdot \frac{-1}{1 + \sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}}}{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

        \[\leadsto \frac{\left(\frac{\frac{1}{4}}{\mathsf{fma}\left(x, x, 1\right)} + \frac{-1}{4}\right) \cdot \color{blue}{\frac{-1}{1 + \sqrt{\frac{1}{2} + \frac{\frac{1}{2}}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}}}}{\frac{1}{2} + \frac{\frac{1}{2}}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}} \]
      3. associate-*r/N/A

        \[\leadsto \frac{\color{blue}{\frac{\left(\frac{\frac{1}{4}}{\mathsf{fma}\left(x, x, 1\right)} + \frac{-1}{4}\right) \cdot -1}{1 + \sqrt{\frac{1}{2} + \frac{\frac{1}{2}}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}}}}{\frac{1}{2} + \frac{\frac{1}{2}}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}} \]
    6. Applied rewrites99.9%

      \[\leadsto \frac{\color{blue}{\frac{0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}}{1 + \sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}}}}{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 2: 99.9% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}\\ \mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 1.005:\\ \;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)\\ \mathbf{else}:\\ \;\;\;\;\left(0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}\right) \cdot \frac{1}{t\_0 \cdot \left(1 + \sqrt{t\_0}\right)}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (+ 0.5 (/ 0.5 (sqrt (fma x x 1.0))))))
   (if (<= (hypot 1.0 x) 1.005)
     (*
      (* x x)
      (fma
       (* x x)
       (fma (* x x) (fma (* x x) -0.056243896484375 0.0673828125) -0.0859375)
       0.125))
     (* (- 0.25 (/ 0.25 (fma x x 1.0))) (/ 1.0 (* t_0 (+ 1.0 (sqrt t_0))))))))
double code(double x) {
	double t_0 = 0.5 + (0.5 / sqrt(fma(x, x, 1.0)));
	double tmp;
	if (hypot(1.0, x) <= 1.005) {
		tmp = (x * x) * fma((x * x), fma((x * x), fma((x * x), -0.056243896484375, 0.0673828125), -0.0859375), 0.125);
	} else {
		tmp = (0.25 - (0.25 / fma(x, x, 1.0))) * (1.0 / (t_0 * (1.0 + sqrt(t_0))));
	}
	return tmp;
}
function code(x)
	t_0 = Float64(0.5 + Float64(0.5 / sqrt(fma(x, x, 1.0))))
	tmp = 0.0
	if (hypot(1.0, x) <= 1.005)
		tmp = Float64(Float64(x * x) * fma(Float64(x * x), fma(Float64(x * x), fma(Float64(x * x), -0.056243896484375, 0.0673828125), -0.0859375), 0.125));
	else
		tmp = Float64(Float64(0.25 - Float64(0.25 / fma(x, x, 1.0))) * Float64(1.0 / Float64(t_0 * Float64(1.0 + sqrt(t_0)))));
	end
	return tmp
end
code[x_] := Block[{t$95$0 = N[(0.5 + N[(0.5 / N[Sqrt[N[(x * x + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 1.005], N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * -0.056243896484375 + 0.0673828125), $MachinePrecision] + -0.0859375), $MachinePrecision] + 0.125), $MachinePrecision]), $MachinePrecision], N[(N[(0.25 - N[(0.25 / N[(x * x + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(1.0 / N[(t$95$0 * N[(1.0 + N[Sqrt[t$95$0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}\\
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 1.005:\\
\;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)\\

\mathbf{else}:\\
\;\;\;\;\left(0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}\right) \cdot \frac{1}{t\_0 \cdot \left(1 + \sqrt{t\_0}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (hypot.f64 #s(literal 1 binary64) x) < 1.0049999999999999

    1. Initial program 53.4%

      \[1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \]
    2. Add Preprocessing
    3. Applied rewrites53.5%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}} + -0.5}{-1 + \left(-\sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}\right)}} \]
    4. Taylor expanded in x around 0

      \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right)} \]
    5. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right)} \]
      2. unpow2N/A

        \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right) \]
      3. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{8} + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right)\right) \]
      4. +-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}\right) + \frac{1}{8}\right)} \]
      5. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\mathsf{fma}\left({x}^{2}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right)} \]
      6. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(\color{blue}{x \cdot x}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right) \]
      7. lower-*.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(\color{blue}{x \cdot x}, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) - \frac{11}{128}, \frac{1}{8}\right) \]
      8. sub-negN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \color{blue}{{x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) + \left(\mathsf{neg}\left(\frac{11}{128}\right)\right)}, \frac{1}{8}\right) \]
      9. metadata-evalN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, {x}^{2} \cdot \left(\frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}\right) + \color{blue}{\frac{-11}{128}}, \frac{1}{8}\right) \]
      10. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right)}, \frac{1}{8}\right) \]
      11. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      12. lower-*.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{69}{1024} + \frac{-1843}{32768} \cdot {x}^{2}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      13. +-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{\frac{-1843}{32768} \cdot {x}^{2} + \frac{69}{1024}}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      14. *-commutativeN/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{{x}^{2} \cdot \frac{-1843}{32768}} + \frac{69}{1024}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      15. lower-fma.f64N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{-1843}{32768}, \frac{69}{1024}\right)}, \frac{-11}{128}\right), \frac{1}{8}\right) \]
      16. unpow2N/A

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{-1843}{32768}, \frac{69}{1024}\right), \frac{-11}{128}\right), \frac{1}{8}\right) \]
      17. lower-*.f6499.9

        \[\leadsto \left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(\color{blue}{x \cdot x}, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right) \]
    6. Applied rewrites99.9%

      \[\leadsto \color{blue}{\left(x \cdot x\right) \cdot \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, \mathsf{fma}\left(x \cdot x, -0.056243896484375, 0.0673828125\right), -0.0859375\right), 0.125\right)} \]

    if 1.0049999999999999 < (hypot.f64 #s(literal 1 binary64) x)

    1. Initial program 98.5%

      \[1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)} \]
    2. Add Preprocessing
    3. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}} + -0.5}{-1 + \left(-\sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}\right)}} \]
    4. Applied rewrites99.9%

      \[\leadsto \color{blue}{\frac{\left(\frac{0.25}{\mathsf{fma}\left(x, x, 1\right)} + -0.25\right) \cdot \frac{-1}{1 + \sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}}}{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}} \]
    5. Applied rewrites99.9%

      \[\leadsto \color{blue}{\left(0.25 - \frac{0.25}{\mathsf{fma}\left(x, x, 1\right)}\right) \cdot \frac{1}{\left(0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}\right) \cdot \left(1 + \sqrt{0.5 + \frac{0.5}{\sqrt{\mathsf{fma}\left(x, x, 1\right)}}}\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Reproduce

?
herbie shell --seed 2024228 
(FPCore (x)
  :name "Given's Rotation SVD example, simplified"
  :precision binary64
  (- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))