sqrt D (should all be same)

Percentage Accurate: 54.1% → 99.4%
Time: 12.4s
Alternatives: 6
Speedup: 4.9×

Specification

?
\[\begin{array}{l} \\ \sqrt{2 \cdot {x}^{2}} \end{array} \]
(FPCore (x) :precision binary64 (sqrt (* 2.0 (pow x 2.0))))
double code(double x) {
	return sqrt((2.0 * pow(x, 2.0)));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sqrt((2.0d0 * (x ** 2.0d0)))
end function
public static double code(double x) {
	return Math.sqrt((2.0 * Math.pow(x, 2.0)));
}
def code(x):
	return math.sqrt((2.0 * math.pow(x, 2.0)))
function code(x)
	return sqrt(Float64(2.0 * (x ^ 2.0)))
end
function tmp = code(x)
	tmp = sqrt((2.0 * (x ^ 2.0)));
end
code[x_] := N[Sqrt[N[(2.0 * N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2 \cdot {x}^{2}}
\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: 54.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{2 \cdot {x}^{2}} \end{array} \]
(FPCore (x) :precision binary64 (sqrt (* 2.0 (pow x 2.0))))
double code(double x) {
	return sqrt((2.0 * pow(x, 2.0)));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sqrt((2.0d0 * (x ** 2.0d0)))
end function
public static double code(double x) {
	return Math.sqrt((2.0 * Math.pow(x, 2.0)));
}
def code(x):
	return math.sqrt((2.0 * math.pow(x, 2.0)))
function code(x)
	return sqrt(Float64(2.0 * (x ^ 2.0)))
end
function tmp = code(x)
	tmp = sqrt((2.0 * (x ^ 2.0)));
end
code[x_] := N[Sqrt[N[(2.0 * N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{2 \cdot {x}^{2}}
\end{array}

Alternative 1: 99.4% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\ \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\sqrt{2 \cdot x}}{{x}^{-0.5}}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -2e-310)
   (/ (* -2.0 x) (sqrt 2.0))
   (/ (sqrt (* 2.0 x)) (pow x -0.5))))
double code(double x) {
	double tmp;
	if (x <= -2e-310) {
		tmp = (-2.0 * x) / sqrt(2.0);
	} else {
		tmp = sqrt((2.0 * x)) / pow(x, -0.5);
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-2d-310)) then
        tmp = ((-2.0d0) * x) / sqrt(2.0d0)
    else
        tmp = sqrt((2.0d0 * x)) / (x ** (-0.5d0))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -2e-310) {
		tmp = (-2.0 * x) / Math.sqrt(2.0);
	} else {
		tmp = Math.sqrt((2.0 * x)) / Math.pow(x, -0.5);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -2e-310:
		tmp = (-2.0 * x) / math.sqrt(2.0)
	else:
		tmp = math.sqrt((2.0 * x)) / math.pow(x, -0.5)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -2e-310)
		tmp = Float64(Float64(-2.0 * x) / sqrt(2.0));
	else
		tmp = Float64(sqrt(Float64(2.0 * x)) / (x ^ -0.5));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -2e-310)
		tmp = (-2.0 * x) / sqrt(2.0);
	else
		tmp = sqrt((2.0 * x)) / (x ^ -0.5);
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -2e-310], N[(N[(-2.0 * x), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[N[(2.0 * x), $MachinePrecision]], $MachinePrecision] / N[Power[x, -0.5], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\
\;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\sqrt{2 \cdot x}}{{x}^{-0.5}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1.999999999999994e-310

    1. Initial program 53.3%

      \[\sqrt{2 \cdot {x}^{2}} \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
    4. Step-by-step derivation
      1. associate-*r*N/A

        \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
      3. mul-1-negN/A

        \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
      4. lower-neg.f64N/A

        \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
      5. lower-sqrt.f6499.3

        \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
    5. Applied rewrites99.3%

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

        \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \color{blue}{\left(-{4}^{0.125}\right)} \]
      2. Step-by-step derivation
        1. Applied rewrites99.4%

          \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \left(-\sqrt{\sqrt{2}}\right) \]
        2. Step-by-step derivation
          1. Applied rewrites99.4%

            \[\leadsto \frac{-2 \cdot x}{\color{blue}{\sqrt{2}}} \]

          if -1.999999999999994e-310 < x

          1. Initial program 49.7%

            \[\sqrt{2 \cdot {x}^{2}} \]
          2. Add Preprocessing
          3. Taylor expanded in x around -inf

            \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
          4. Step-by-step derivation
            1. associate-*r*N/A

              \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
            2. lower-*.f64N/A

              \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
            3. mul-1-negN/A

              \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
            4. lower-neg.f64N/A

              \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
            5. lower-sqrt.f642.1

              \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
          5. Applied rewrites2.1%

            \[\leadsto \color{blue}{\left(-x\right) \cdot \sqrt{2}} \]
          6. Step-by-step derivation
            1. Applied rewrites2.1%

              \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \color{blue}{\left(-{4}^{0.125}\right)} \]
            2. Applied rewrites99.6%

              \[\leadsto \frac{\sqrt{2 \cdot x}}{\color{blue}{{x}^{-0.5}}} \]
          7. Recombined 2 regimes into one program.
          8. Add Preprocessing

          Alternative 2: 99.4% accurate, 3.2× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\ \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{x} \cdot \sqrt{2 \cdot x}\\ \end{array} \end{array} \]
          (FPCore (x)
           :precision binary64
           (if (<= x -2e-310) (/ (* -2.0 x) (sqrt 2.0)) (* (sqrt x) (sqrt (* 2.0 x)))))
          double code(double x) {
          	double tmp;
          	if (x <= -2e-310) {
          		tmp = (-2.0 * x) / sqrt(2.0);
          	} else {
          		tmp = sqrt(x) * sqrt((2.0 * x));
          	}
          	return tmp;
          }
          
          real(8) function code(x)
              real(8), intent (in) :: x
              real(8) :: tmp
              if (x <= (-2d-310)) then
                  tmp = ((-2.0d0) * x) / sqrt(2.0d0)
              else
                  tmp = sqrt(x) * sqrt((2.0d0 * x))
              end if
              code = tmp
          end function
          
          public static double code(double x) {
          	double tmp;
          	if (x <= -2e-310) {
          		tmp = (-2.0 * x) / Math.sqrt(2.0);
          	} else {
          		tmp = Math.sqrt(x) * Math.sqrt((2.0 * x));
          	}
          	return tmp;
          }
          
          def code(x):
          	tmp = 0
          	if x <= -2e-310:
          		tmp = (-2.0 * x) / math.sqrt(2.0)
          	else:
          		tmp = math.sqrt(x) * math.sqrt((2.0 * x))
          	return tmp
          
          function code(x)
          	tmp = 0.0
          	if (x <= -2e-310)
          		tmp = Float64(Float64(-2.0 * x) / sqrt(2.0));
          	else
          		tmp = Float64(sqrt(x) * sqrt(Float64(2.0 * x)));
          	end
          	return tmp
          end
          
          function tmp_2 = code(x)
          	tmp = 0.0;
          	if (x <= -2e-310)
          		tmp = (-2.0 * x) / sqrt(2.0);
          	else
          		tmp = sqrt(x) * sqrt((2.0 * x));
          	end
          	tmp_2 = tmp;
          end
          
          code[x_] := If[LessEqual[x, -2e-310], N[(N[(-2.0 * x), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[x], $MachinePrecision] * N[Sqrt[N[(2.0 * x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\
          \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\
          
          \mathbf{else}:\\
          \;\;\;\;\sqrt{x} \cdot \sqrt{2 \cdot x}\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if x < -1.999999999999994e-310

            1. Initial program 53.3%

              \[\sqrt{2 \cdot {x}^{2}} \]
            2. Add Preprocessing
            3. Taylor expanded in x around -inf

              \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
            4. Step-by-step derivation
              1. associate-*r*N/A

                \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
              2. lower-*.f64N/A

                \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
              3. mul-1-negN/A

                \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
              4. lower-neg.f64N/A

                \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
              5. lower-sqrt.f6499.3

                \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
            5. Applied rewrites99.3%

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

                \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \color{blue}{\left(-{4}^{0.125}\right)} \]
              2. Step-by-step derivation
                1. Applied rewrites99.4%

                  \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \left(-\sqrt{\sqrt{2}}\right) \]
                2. Step-by-step derivation
                  1. Applied rewrites99.4%

                    \[\leadsto \frac{-2 \cdot x}{\color{blue}{\sqrt{2}}} \]

                  if -1.999999999999994e-310 < x

                  1. Initial program 49.7%

                    \[\sqrt{2 \cdot {x}^{2}} \]
                  2. Add Preprocessing
                  3. Taylor expanded in x around -inf

                    \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
                  4. Step-by-step derivation
                    1. associate-*r*N/A

                      \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                    2. lower-*.f64N/A

                      \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                    3. mul-1-negN/A

                      \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
                    4. lower-neg.f64N/A

                      \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
                    5. lower-sqrt.f642.1

                      \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
                  5. Applied rewrites2.1%

                    \[\leadsto \color{blue}{\left(-x\right) \cdot \sqrt{2}} \]
                  6. Step-by-step derivation
                    1. Applied rewrites99.5%

                      \[\leadsto \sqrt{x \cdot 2} \cdot \color{blue}{\sqrt{x}} \]
                  7. Recombined 2 regimes into one program.
                  8. Final simplification99.4%

                    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\ \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{x} \cdot \sqrt{2 \cdot x}\\ \end{array} \]
                  9. Add Preprocessing

                  Alternative 3: 99.3% accurate, 3.5× speedup?

                  \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\ \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2} \cdot x\\ \end{array} \end{array} \]
                  (FPCore (x)
                   :precision binary64
                   (if (<= x -2e-310) (/ (* -2.0 x) (sqrt 2.0)) (* (sqrt 2.0) x)))
                  double code(double x) {
                  	double tmp;
                  	if (x <= -2e-310) {
                  		tmp = (-2.0 * x) / sqrt(2.0);
                  	} else {
                  		tmp = sqrt(2.0) * x;
                  	}
                  	return tmp;
                  }
                  
                  real(8) function code(x)
                      real(8), intent (in) :: x
                      real(8) :: tmp
                      if (x <= (-2d-310)) then
                          tmp = ((-2.0d0) * x) / sqrt(2.0d0)
                      else
                          tmp = sqrt(2.0d0) * x
                      end if
                      code = tmp
                  end function
                  
                  public static double code(double x) {
                  	double tmp;
                  	if (x <= -2e-310) {
                  		tmp = (-2.0 * x) / Math.sqrt(2.0);
                  	} else {
                  		tmp = Math.sqrt(2.0) * x;
                  	}
                  	return tmp;
                  }
                  
                  def code(x):
                  	tmp = 0
                  	if x <= -2e-310:
                  		tmp = (-2.0 * x) / math.sqrt(2.0)
                  	else:
                  		tmp = math.sqrt(2.0) * x
                  	return tmp
                  
                  function code(x)
                  	tmp = 0.0
                  	if (x <= -2e-310)
                  		tmp = Float64(Float64(-2.0 * x) / sqrt(2.0));
                  	else
                  		tmp = Float64(sqrt(2.0) * x);
                  	end
                  	return tmp
                  end
                  
                  function tmp_2 = code(x)
                  	tmp = 0.0;
                  	if (x <= -2e-310)
                  		tmp = (-2.0 * x) / sqrt(2.0);
                  	else
                  		tmp = sqrt(2.0) * x;
                  	end
                  	tmp_2 = tmp;
                  end
                  
                  code[x_] := If[LessEqual[x, -2e-310], N[(N[(-2.0 * x), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[2.0], $MachinePrecision] * x), $MachinePrecision]]
                  
                  \begin{array}{l}
                  
                  \\
                  \begin{array}{l}
                  \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\
                  \;\;\;\;\frac{-2 \cdot x}{\sqrt{2}}\\
                  
                  \mathbf{else}:\\
                  \;\;\;\;\sqrt{2} \cdot x\\
                  
                  
                  \end{array}
                  \end{array}
                  
                  Derivation
                  1. Split input into 2 regimes
                  2. if x < -1.999999999999994e-310

                    1. Initial program 53.3%

                      \[\sqrt{2 \cdot {x}^{2}} \]
                    2. Add Preprocessing
                    3. Taylor expanded in x around -inf

                      \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
                    4. Step-by-step derivation
                      1. associate-*r*N/A

                        \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                      2. lower-*.f64N/A

                        \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                      3. mul-1-negN/A

                        \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
                      4. lower-neg.f64N/A

                        \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
                      5. lower-sqrt.f6499.3

                        \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
                    5. Applied rewrites99.3%

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

                        \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \color{blue}{\left(-{4}^{0.125}\right)} \]
                      2. Step-by-step derivation
                        1. Applied rewrites99.4%

                          \[\leadsto \left({4}^{0.125} \cdot x\right) \cdot \left(-\sqrt{\sqrt{2}}\right) \]
                        2. Step-by-step derivation
                          1. Applied rewrites99.4%

                            \[\leadsto \frac{-2 \cdot x}{\color{blue}{\sqrt{2}}} \]

                          if -1.999999999999994e-310 < x

                          1. Initial program 49.7%

                            \[\sqrt{2 \cdot {x}^{2}} \]
                          2. Add Preprocessing
                          3. Applied rewrites99.5%

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

                        Alternative 4: 99.3% accurate, 4.9× speedup?

                        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\ \;\;\;\;\left(-x\right) \cdot \sqrt{2}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2} \cdot x\\ \end{array} \end{array} \]
                        (FPCore (x)
                         :precision binary64
                         (if (<= x -2e-310) (* (- x) (sqrt 2.0)) (* (sqrt 2.0) x)))
                        double code(double x) {
                        	double tmp;
                        	if (x <= -2e-310) {
                        		tmp = -x * sqrt(2.0);
                        	} else {
                        		tmp = sqrt(2.0) * x;
                        	}
                        	return tmp;
                        }
                        
                        real(8) function code(x)
                            real(8), intent (in) :: x
                            real(8) :: tmp
                            if (x <= (-2d-310)) then
                                tmp = -x * sqrt(2.0d0)
                            else
                                tmp = sqrt(2.0d0) * x
                            end if
                            code = tmp
                        end function
                        
                        public static double code(double x) {
                        	double tmp;
                        	if (x <= -2e-310) {
                        		tmp = -x * Math.sqrt(2.0);
                        	} else {
                        		tmp = Math.sqrt(2.0) * x;
                        	}
                        	return tmp;
                        }
                        
                        def code(x):
                        	tmp = 0
                        	if x <= -2e-310:
                        		tmp = -x * math.sqrt(2.0)
                        	else:
                        		tmp = math.sqrt(2.0) * x
                        	return tmp
                        
                        function code(x)
                        	tmp = 0.0
                        	if (x <= -2e-310)
                        		tmp = Float64(Float64(-x) * sqrt(2.0));
                        	else
                        		tmp = Float64(sqrt(2.0) * x);
                        	end
                        	return tmp
                        end
                        
                        function tmp_2 = code(x)
                        	tmp = 0.0;
                        	if (x <= -2e-310)
                        		tmp = -x * sqrt(2.0);
                        	else
                        		tmp = sqrt(2.0) * x;
                        	end
                        	tmp_2 = tmp;
                        end
                        
                        code[x_] := If[LessEqual[x, -2e-310], N[((-x) * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[2.0], $MachinePrecision] * x), $MachinePrecision]]
                        
                        \begin{array}{l}
                        
                        \\
                        \begin{array}{l}
                        \mathbf{if}\;x \leq -2 \cdot 10^{-310}:\\
                        \;\;\;\;\left(-x\right) \cdot \sqrt{2}\\
                        
                        \mathbf{else}:\\
                        \;\;\;\;\sqrt{2} \cdot x\\
                        
                        
                        \end{array}
                        \end{array}
                        
                        Derivation
                        1. Split input into 2 regimes
                        2. if x < -1.999999999999994e-310

                          1. Initial program 53.3%

                            \[\sqrt{2 \cdot {x}^{2}} \]
                          2. Add Preprocessing
                          3. Taylor expanded in x around -inf

                            \[\leadsto \color{blue}{-1 \cdot \left(x \cdot \sqrt{2}\right)} \]
                          4. Step-by-step derivation
                            1. associate-*r*N/A

                              \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                            2. lower-*.f64N/A

                              \[\leadsto \color{blue}{\left(-1 \cdot x\right) \cdot \sqrt{2}} \]
                            3. mul-1-negN/A

                              \[\leadsto \color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot \sqrt{2} \]
                            4. lower-neg.f64N/A

                              \[\leadsto \color{blue}{\left(-x\right)} \cdot \sqrt{2} \]
                            5. lower-sqrt.f6499.3

                              \[\leadsto \left(-x\right) \cdot \color{blue}{\sqrt{2}} \]
                          5. Applied rewrites99.3%

                            \[\leadsto \color{blue}{\left(-x\right) \cdot \sqrt{2}} \]

                          if -1.999999999999994e-310 < x

                          1. Initial program 49.7%

                            \[\sqrt{2 \cdot {x}^{2}} \]
                          2. Add Preprocessing
                          3. Applied rewrites99.5%

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

                        Alternative 5: 53.1% accurate, 5.3× speedup?

                        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -4.1 \cdot 10^{-206}:\\ \;\;\;\;\sqrt{2}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2} \cdot x\\ \end{array} \end{array} \]
                        (FPCore (x)
                         :precision binary64
                         (if (<= x -4.1e-206) (sqrt 2.0) (* (sqrt 2.0) x)))
                        double code(double x) {
                        	double tmp;
                        	if (x <= -4.1e-206) {
                        		tmp = sqrt(2.0);
                        	} else {
                        		tmp = sqrt(2.0) * x;
                        	}
                        	return tmp;
                        }
                        
                        real(8) function code(x)
                            real(8), intent (in) :: x
                            real(8) :: tmp
                            if (x <= (-4.1d-206)) then
                                tmp = sqrt(2.0d0)
                            else
                                tmp = sqrt(2.0d0) * x
                            end if
                            code = tmp
                        end function
                        
                        public static double code(double x) {
                        	double tmp;
                        	if (x <= -4.1e-206) {
                        		tmp = Math.sqrt(2.0);
                        	} else {
                        		tmp = Math.sqrt(2.0) * x;
                        	}
                        	return tmp;
                        }
                        
                        def code(x):
                        	tmp = 0
                        	if x <= -4.1e-206:
                        		tmp = math.sqrt(2.0)
                        	else:
                        		tmp = math.sqrt(2.0) * x
                        	return tmp
                        
                        function code(x)
                        	tmp = 0.0
                        	if (x <= -4.1e-206)
                        		tmp = sqrt(2.0);
                        	else
                        		tmp = Float64(sqrt(2.0) * x);
                        	end
                        	return tmp
                        end
                        
                        function tmp_2 = code(x)
                        	tmp = 0.0;
                        	if (x <= -4.1e-206)
                        		tmp = sqrt(2.0);
                        	else
                        		tmp = sqrt(2.0) * x;
                        	end
                        	tmp_2 = tmp;
                        end
                        
                        code[x_] := If[LessEqual[x, -4.1e-206], N[Sqrt[2.0], $MachinePrecision], N[(N[Sqrt[2.0], $MachinePrecision] * x), $MachinePrecision]]
                        
                        \begin{array}{l}
                        
                        \\
                        \begin{array}{l}
                        \mathbf{if}\;x \leq -4.1 \cdot 10^{-206}:\\
                        \;\;\;\;\sqrt{2}\\
                        
                        \mathbf{else}:\\
                        \;\;\;\;\sqrt{2} \cdot x\\
                        
                        
                        \end{array}
                        \end{array}
                        
                        Derivation
                        1. Split input into 2 regimes
                        2. if x < -4.10000000000000016e-206

                          1. Initial program 61.6%

                            \[\sqrt{2 \cdot {x}^{2}} \]
                          2. Add Preprocessing
                          3. Applied rewrites5.7%

                            \[\leadsto \color{blue}{\sqrt{2}} \]

                          if -4.10000000000000016e-206 < x

                          1. Initial program 44.0%

                            \[\sqrt{2 \cdot {x}^{2}} \]
                          2. Add Preprocessing
                          3. Applied rewrites86.9%

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

                        Alternative 6: 5.4% accurate, 10.6× speedup?

                        \[\begin{array}{l} \\ \sqrt{2} \end{array} \]
                        (FPCore (x) :precision binary64 (sqrt 2.0))
                        double code(double x) {
                        	return sqrt(2.0);
                        }
                        
                        real(8) function code(x)
                            real(8), intent (in) :: x
                            code = sqrt(2.0d0)
                        end function
                        
                        public static double code(double x) {
                        	return Math.sqrt(2.0);
                        }
                        
                        def code(x):
                        	return math.sqrt(2.0)
                        
                        function code(x)
                        	return sqrt(2.0)
                        end
                        
                        function tmp = code(x)
                        	tmp = sqrt(2.0);
                        end
                        
                        code[x_] := N[Sqrt[2.0], $MachinePrecision]
                        
                        \begin{array}{l}
                        
                        \\
                        \sqrt{2}
                        \end{array}
                        
                        Derivation
                        1. Initial program 51.5%

                          \[\sqrt{2 \cdot {x}^{2}} \]
                        2. Add Preprocessing
                        3. Applied rewrites5.1%

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

                        Reproduce

                        ?
                        herbie shell --seed 2024288 
                        (FPCore (x)
                          :name "sqrt D (should all be same)"
                          :precision binary64
                          (sqrt (* 2.0 (pow x 2.0))))