Data.Octree.Internal:octantDistance from Octree-0.5.4.2

Percentage Accurate: 53.9% → 100.0%
Time: 4.4s
Alternatives: 5
Speedup: 0.2×

Specification

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

\\
\sqrt{x \cdot x + y \cdot y}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 5 alternatives:

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

Initial Program: 53.9% accurate, 1.0× speedup?

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

\\
\sqrt{x \cdot x + y \cdot y}
\end{array}

Alternative 1: 100.0% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \mathsf{hypot}\left(y, x\right) \end{array} \]
(FPCore (x y) :precision binary64 (hypot y x))
double code(double x, double y) {
	return hypot(y, x);
}
public static double code(double x, double y) {
	return Math.hypot(y, x);
}
def code(x, y):
	return math.hypot(y, x)
function code(x, y)
	return hypot(y, x)
end
function tmp = code(x, y)
	tmp = hypot(y, x);
end
code[x_, y_] := N[Sqrt[y ^ 2 + x ^ 2], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{hypot}\left(y, x\right)
\end{array}
Derivation
  1. Initial program 52.9%

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

      \[\leadsto \color{blue}{\sqrt{x \cdot x + y \cdot y}} \]
    2. lift-+.f64N/A

      \[\leadsto \sqrt{\color{blue}{x \cdot x + y \cdot y}} \]
    3. +-commutativeN/A

      \[\leadsto \sqrt{\color{blue}{y \cdot y + x \cdot x}} \]
    4. lift-*.f64N/A

      \[\leadsto \sqrt{\color{blue}{y \cdot y} + x \cdot x} \]
    5. lift-*.f64N/A

      \[\leadsto \sqrt{y \cdot y + \color{blue}{x \cdot x}} \]
    6. lower-hypot.f64100.0

      \[\leadsto \color{blue}{\mathsf{hypot}\left(y, x\right)} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\mathsf{hypot}\left(y, x\right)} \]
  5. Add Preprocessing

Alternative 2: 26.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\frac{0.5}{y} \cdot x, x, y\right) \end{array} \]
(FPCore (x y) :precision binary64 (fma (* (/ 0.5 y) x) x y))
double code(double x, double y) {
	return fma(((0.5 / y) * x), x, y);
}
function code(x, y)
	return fma(Float64(Float64(0.5 / y) * x), x, y)
end
code[x_, y_] := N[(N[(N[(0.5 / y), $MachinePrecision] * x), $MachinePrecision] * x + y), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\frac{0.5}{y} \cdot x, x, y\right)
\end{array}
Derivation
  1. Initial program 52.9%

    \[\sqrt{x \cdot x + y \cdot y} \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

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

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{{x}^{2}}{y} + y} \]
    2. *-lft-identityN/A

      \[\leadsto \frac{1}{2} \cdot \frac{\color{blue}{1 \cdot {x}^{2}}}{y} + y \]
    3. associate-*l/N/A

      \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\frac{1}{y} \cdot {x}^{2}\right)} + y \]
    4. associate-*l*N/A

      \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{y}\right) \cdot {x}^{2}} + y \]
    5. lower-fma.f64N/A

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

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2} \cdot 1}{y}}, {x}^{2}, y\right) \]
    7. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\frac{1}{2}}}{y}, {x}^{2}, y\right) \]
    8. lower-/.f64N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2}}{y}}, {x}^{2}, y\right) \]
    9. unpow2N/A

      \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{y}, \color{blue}{x \cdot x}, y\right) \]
    10. lower-*.f6425.3

      \[\leadsto \mathsf{fma}\left(\frac{0.5}{y}, \color{blue}{x \cdot x}, y\right) \]
  5. Applied rewrites25.3%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{0.5}{y}, x \cdot x, y\right)} \]
  6. Step-by-step derivation
    1. Applied rewrites26.7%

      \[\leadsto \mathsf{fma}\left(\frac{0.5}{y} \cdot x, \color{blue}{x}, y\right) \]
    2. Add Preprocessing

    Alternative 3: 53.9% accurate, 1.1× speedup?

    \[\begin{array}{l} \\ \sqrt{\mathsf{fma}\left(y, y, x \cdot x\right)} \end{array} \]
    (FPCore (x y) :precision binary64 (sqrt (fma y y (* x x))))
    double code(double x, double y) {
    	return sqrt(fma(y, y, (x * x)));
    }
    
    function code(x, y)
    	return sqrt(fma(y, y, Float64(x * x)))
    end
    
    code[x_, y_] := N[Sqrt[N[(y * y + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \sqrt{\mathsf{fma}\left(y, y, x \cdot x\right)}
    \end{array}
    
    Derivation
    1. Initial program 52.9%

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

        \[\leadsto \sqrt{\color{blue}{x \cdot x + y \cdot y}} \]
      2. +-commutativeN/A

        \[\leadsto \sqrt{\color{blue}{y \cdot y + x \cdot x}} \]
      3. lift-*.f64N/A

        \[\leadsto \sqrt{\color{blue}{y \cdot y} + x \cdot x} \]
      4. lower-fma.f6452.9

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right)}} \]
    4. Applied rewrites52.9%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right)}} \]
    5. Add Preprocessing

    Alternative 4: 28.2% accurate, 1.5× speedup?

    \[\begin{array}{l} \\ \sqrt{y \cdot y} \end{array} \]
    (FPCore (x y) :precision binary64 (sqrt (* y y)))
    double code(double x, double y) {
    	return sqrt((y * y));
    }
    
    real(8) function code(x, y)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        code = sqrt((y * y))
    end function
    
    public static double code(double x, double y) {
    	return Math.sqrt((y * y));
    }
    
    def code(x, y):
    	return math.sqrt((y * y))
    
    function code(x, y)
    	return sqrt(Float64(y * y))
    end
    
    function tmp = code(x, y)
    	tmp = sqrt((y * y));
    end
    
    code[x_, y_] := N[Sqrt[N[(y * y), $MachinePrecision]], $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \sqrt{y \cdot y}
    \end{array}
    
    Derivation
    1. Initial program 52.9%

      \[\sqrt{x \cdot x + y \cdot y} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \sqrt{\color{blue}{{y}^{2}}} \]
    4. Step-by-step derivation
      1. unpow2N/A

        \[\leadsto \sqrt{\color{blue}{y \cdot y}} \]
      2. lower-*.f6426.9

        \[\leadsto \sqrt{\color{blue}{y \cdot y}} \]
    5. Applied rewrites26.9%

      \[\leadsto \sqrt{\color{blue}{y \cdot y}} \]
    6. Add Preprocessing

    Alternative 5: 27.2% accurate, 24.0× speedup?

    \[\begin{array}{l} \\ x \end{array} \]
    (FPCore (x y) :precision binary64 x)
    double code(double x, double y) {
    	return x;
    }
    
    real(8) function code(x, y)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        code = x
    end function
    
    public static double code(double x, double y) {
    	return x;
    }
    
    def code(x, y):
    	return x
    
    function code(x, y)
    	return x
    end
    
    function tmp = code(x, y)
    	tmp = x;
    end
    
    code[x_, y_] := x
    
    \begin{array}{l}
    
    \\
    x
    \end{array}
    
    Derivation
    1. Initial program 52.9%

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

      \[\leadsto \color{blue}{-1 \cdot x} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(x\right)} \]
      2. lower-neg.f6431.6

        \[\leadsto \color{blue}{-x} \]
    5. Applied rewrites31.6%

      \[\leadsto \color{blue}{-x} \]
    6. Step-by-step derivation
      1. Applied rewrites22.8%

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

      Developer Target 1: 73.7% accurate, 0.7× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x < -1.1236950826599826 \cdot 10^{+145}:\\ \;\;\;\;-x\\ \mathbf{elif}\;x < 1.116557621183362 \cdot 10^{+93}:\\ \;\;\;\;\sqrt{x \cdot x + y \cdot y}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \end{array} \]
      (FPCore (x y)
       :precision binary64
       (if (< x -1.1236950826599826e+145)
         (- x)
         (if (< x 1.116557621183362e+93) (sqrt (+ (* x x) (* y y))) x)))
      double code(double x, double y) {
      	double tmp;
      	if (x < -1.1236950826599826e+145) {
      		tmp = -x;
      	} else if (x < 1.116557621183362e+93) {
      		tmp = sqrt(((x * x) + (y * y)));
      	} else {
      		tmp = x;
      	}
      	return tmp;
      }
      
      real(8) function code(x, y)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          real(8) :: tmp
          if (x < (-1.1236950826599826d+145)) then
              tmp = -x
          else if (x < 1.116557621183362d+93) then
              tmp = sqrt(((x * x) + (y * y)))
          else
              tmp = x
          end if
          code = tmp
      end function
      
      public static double code(double x, double y) {
      	double tmp;
      	if (x < -1.1236950826599826e+145) {
      		tmp = -x;
      	} else if (x < 1.116557621183362e+93) {
      		tmp = Math.sqrt(((x * x) + (y * y)));
      	} else {
      		tmp = x;
      	}
      	return tmp;
      }
      
      def code(x, y):
      	tmp = 0
      	if x < -1.1236950826599826e+145:
      		tmp = -x
      	elif x < 1.116557621183362e+93:
      		tmp = math.sqrt(((x * x) + (y * y)))
      	else:
      		tmp = x
      	return tmp
      
      function code(x, y)
      	tmp = 0.0
      	if (x < -1.1236950826599826e+145)
      		tmp = Float64(-x);
      	elseif (x < 1.116557621183362e+93)
      		tmp = sqrt(Float64(Float64(x * x) + Float64(y * y)));
      	else
      		tmp = x;
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y)
      	tmp = 0.0;
      	if (x < -1.1236950826599826e+145)
      		tmp = -x;
      	elseif (x < 1.116557621183362e+93)
      		tmp = sqrt(((x * x) + (y * y)));
      	else
      		tmp = x;
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_] := If[Less[x, -1.1236950826599826e+145], (-x), If[Less[x, 1.116557621183362e+93], N[Sqrt[N[(N[(x * x), $MachinePrecision] + N[(y * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], x]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;x < -1.1236950826599826 \cdot 10^{+145}:\\
      \;\;\;\;-x\\
      
      \mathbf{elif}\;x < 1.116557621183362 \cdot 10^{+93}:\\
      \;\;\;\;\sqrt{x \cdot x + y \cdot y}\\
      
      \mathbf{else}:\\
      \;\;\;\;x\\
      
      
      \end{array}
      \end{array}
      

      Reproduce

      ?
      herbie shell --seed 2024298 
      (FPCore (x y)
        :name "Data.Octree.Internal:octantDistance  from Octree-0.5.4.2"
        :precision binary64
      
        :alt
        (! :herbie-platform default (if (< x -11236950826599826000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (- x) (if (< x 1116557621183362000000000000000000000000000000000000000000000000000000000000000000000000000000) (sqrt (+ (* x x) (* y y))) x)))
      
        (sqrt (+ (* x x) (* y y))))