Linear.Quaternion:$clog from linear-1.19.1.3

Percentage Accurate: 69.4% → 99.8%
Time: 9.8s
Alternatives: 4
Speedup: 1.0×

Specification

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

\\
\sqrt{x \cdot x + 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 4 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: 69.4% accurate, 1.0× speedup?

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

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

Alternative 1: 99.8% accurate, 0.9× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \cdot x\_m \leq 2 \cdot 10^{+257}:\\ \;\;\;\;\sqrt{x\_m \cdot x\_m + y}\\ \mathbf{else}:\\ \;\;\;\;x\_m\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m y)
 :precision binary64
 (if (<= (* x_m x_m) 2e+257) (sqrt (+ (* x_m x_m) y)) x_m))
x_m = fabs(x);
double code(double x_m, double y) {
	double tmp;
	if ((x_m * x_m) <= 2e+257) {
		tmp = sqrt(((x_m * x_m) + y));
	} else {
		tmp = x_m;
	}
	return tmp;
}
x_m = abs(x)
real(8) function code(x_m, y)
    real(8), intent (in) :: x_m
    real(8), intent (in) :: y
    real(8) :: tmp
    if ((x_m * x_m) <= 2d+257) then
        tmp = sqrt(((x_m * x_m) + y))
    else
        tmp = x_m
    end if
    code = tmp
end function
x_m = Math.abs(x);
public static double code(double x_m, double y) {
	double tmp;
	if ((x_m * x_m) <= 2e+257) {
		tmp = Math.sqrt(((x_m * x_m) + y));
	} else {
		tmp = x_m;
	}
	return tmp;
}
x_m = math.fabs(x)
def code(x_m, y):
	tmp = 0
	if (x_m * x_m) <= 2e+257:
		tmp = math.sqrt(((x_m * x_m) + y))
	else:
		tmp = x_m
	return tmp
x_m = abs(x)
function code(x_m, y)
	tmp = 0.0
	if (Float64(x_m * x_m) <= 2e+257)
		tmp = sqrt(Float64(Float64(x_m * x_m) + y));
	else
		tmp = x_m;
	end
	return tmp
end
x_m = abs(x);
function tmp_2 = code(x_m, y)
	tmp = 0.0;
	if ((x_m * x_m) <= 2e+257)
		tmp = sqrt(((x_m * x_m) + y));
	else
		tmp = x_m;
	end
	tmp_2 = tmp;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_, y_] := If[LessEqual[N[(x$95$m * x$95$m), $MachinePrecision], 2e+257], N[Sqrt[N[(N[(x$95$m * x$95$m), $MachinePrecision] + y), $MachinePrecision]], $MachinePrecision], x$95$m]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
\mathbf{if}\;x\_m \cdot x\_m \leq 2 \cdot 10^{+257}:\\
\;\;\;\;\sqrt{x\_m \cdot x\_m + y}\\

\mathbf{else}:\\
\;\;\;\;x\_m\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 x x) < 2.00000000000000006e257

    1. Initial program 100.0%

      \[\sqrt{x \cdot x + y} \]
    2. Add Preprocessing

    if 2.00000000000000006e257 < (*.f64 x x)

    1. Initial program 23.4%

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

      \[\leadsto \color{blue}{x} \]
    4. Step-by-step derivation
      1. Simplified46.4%

        \[\leadsto \color{blue}{x} \]
    5. Recombined 2 regimes into one program.
    6. Add Preprocessing

    Alternative 2: 86.1% accurate, 1.0× speedup?

    \[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;x\_m \leq 1.42 \cdot 10^{+17}:\\ \;\;\;\;\sqrt{y}\\ \mathbf{else}:\\ \;\;\;\;x\_m + 0.5 \cdot \frac{y}{x\_m}\\ \end{array} \end{array} \]
    x_m = (fabs.f64 x)
    (FPCore (x_m y)
     :precision binary64
     (if (<= x_m 1.42e+17) (sqrt y) (+ x_m (* 0.5 (/ y x_m)))))
    x_m = fabs(x);
    double code(double x_m, double y) {
    	double tmp;
    	if (x_m <= 1.42e+17) {
    		tmp = sqrt(y);
    	} else {
    		tmp = x_m + (0.5 * (y / x_m));
    	}
    	return tmp;
    }
    
    x_m = abs(x)
    real(8) function code(x_m, y)
        real(8), intent (in) :: x_m
        real(8), intent (in) :: y
        real(8) :: tmp
        if (x_m <= 1.42d+17) then
            tmp = sqrt(y)
        else
            tmp = x_m + (0.5d0 * (y / x_m))
        end if
        code = tmp
    end function
    
    x_m = Math.abs(x);
    public static double code(double x_m, double y) {
    	double tmp;
    	if (x_m <= 1.42e+17) {
    		tmp = Math.sqrt(y);
    	} else {
    		tmp = x_m + (0.5 * (y / x_m));
    	}
    	return tmp;
    }
    
    x_m = math.fabs(x)
    def code(x_m, y):
    	tmp = 0
    	if x_m <= 1.42e+17:
    		tmp = math.sqrt(y)
    	else:
    		tmp = x_m + (0.5 * (y / x_m))
    	return tmp
    
    x_m = abs(x)
    function code(x_m, y)
    	tmp = 0.0
    	if (x_m <= 1.42e+17)
    		tmp = sqrt(y);
    	else
    		tmp = Float64(x_m + Float64(0.5 * Float64(y / x_m)));
    	end
    	return tmp
    end
    
    x_m = abs(x);
    function tmp_2 = code(x_m, y)
    	tmp = 0.0;
    	if (x_m <= 1.42e+17)
    		tmp = sqrt(y);
    	else
    		tmp = x_m + (0.5 * (y / x_m));
    	end
    	tmp_2 = tmp;
    end
    
    x_m = N[Abs[x], $MachinePrecision]
    code[x$95$m_, y_] := If[LessEqual[x$95$m, 1.42e+17], N[Sqrt[y], $MachinePrecision], N[(x$95$m + N[(0.5 * N[(y / x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
    
    \begin{array}{l}
    x_m = \left|x\right|
    
    \\
    \begin{array}{l}
    \mathbf{if}\;x\_m \leq 1.42 \cdot 10^{+17}:\\
    \;\;\;\;\sqrt{y}\\
    
    \mathbf{else}:\\
    \;\;\;\;x\_m + 0.5 \cdot \frac{y}{x\_m}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if x < 1.42e17

      1. Initial program 76.6%

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

        \[\leadsto \color{blue}{\sqrt{y}} \]
      4. Step-by-step derivation
        1. sqrt-lowering-sqrt.f6446.2%

          \[\leadsto \mathsf{sqrt.f64}\left(y\right) \]
      5. Simplified46.2%

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

      if 1.42e17 < x

      1. Initial program 50.7%

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

        \[\leadsto \color{blue}{x \cdot \left(1 + \frac{1}{2} \cdot \frac{y}{{x}^{2}}\right)} \]
      4. Step-by-step derivation
        1. distribute-lft-inN/A

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

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

          \[\leadsto \mathsf{+.f64}\left(x, \color{blue}{\left(x \cdot \left(\frac{1}{2} \cdot \frac{y}{{x}^{2}}\right)\right)}\right) \]
        4. *-commutativeN/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\left(\frac{1}{2} \cdot \frac{y}{{x}^{2}}\right) \cdot \color{blue}{x}\right)\right) \]
        5. associate-*l*N/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \color{blue}{\left(\frac{y}{{x}^{2}} \cdot x\right)}\right)\right) \]
        6. associate-*l/N/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y \cdot x}{\color{blue}{{x}^{2}}}\right)\right) \]
        7. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y \cdot x}{x \cdot \color{blue}{x}}\right)\right) \]
        8. times-fracN/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \left(\frac{y}{x} \cdot \color{blue}{\frac{x}{x}}\right)\right)\right) \]
        9. *-inversesN/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \left(\frac{y}{x} \cdot 1\right)\right)\right) \]
        10. *-rgt-identityN/A

          \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y}{\color{blue}{x}}\right)\right) \]
        11. *-lowering-*.f64N/A

          \[\leadsto \mathsf{+.f64}\left(x, \mathsf{*.f64}\left(\frac{1}{2}, \color{blue}{\left(\frac{y}{x}\right)}\right)\right) \]
        12. /-lowering-/.f6495.1%

          \[\leadsto \mathsf{+.f64}\left(x, \mathsf{*.f64}\left(\frac{1}{2}, \mathsf{/.f64}\left(y, \color{blue}{x}\right)\right)\right) \]
      5. Simplified95.1%

        \[\leadsto \color{blue}{x + 0.5 \cdot \frac{y}{x}} \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 3: 68.7% accurate, 15.0× speedup?

    \[\begin{array}{l} x_m = \left|x\right| \\ x\_m + 0.5 \cdot \frac{y}{x\_m} \end{array} \]
    x_m = (fabs.f64 x)
    (FPCore (x_m y) :precision binary64 (+ x_m (* 0.5 (/ y x_m))))
    x_m = fabs(x);
    double code(double x_m, double y) {
    	return x_m + (0.5 * (y / x_m));
    }
    
    x_m = abs(x)
    real(8) function code(x_m, y)
        real(8), intent (in) :: x_m
        real(8), intent (in) :: y
        code = x_m + (0.5d0 * (y / x_m))
    end function
    
    x_m = Math.abs(x);
    public static double code(double x_m, double y) {
    	return x_m + (0.5 * (y / x_m));
    }
    
    x_m = math.fabs(x)
    def code(x_m, y):
    	return x_m + (0.5 * (y / x_m))
    
    x_m = abs(x)
    function code(x_m, y)
    	return Float64(x_m + Float64(0.5 * Float64(y / x_m)))
    end
    
    x_m = abs(x);
    function tmp = code(x_m, y)
    	tmp = x_m + (0.5 * (y / x_m));
    end
    
    x_m = N[Abs[x], $MachinePrecision]
    code[x$95$m_, y_] := N[(x$95$m + N[(0.5 * N[(y / x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    x_m = \left|x\right|
    
    \\
    x\_m + 0.5 \cdot \frac{y}{x\_m}
    \end{array}
    
    Derivation
    1. Initial program 68.9%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + \frac{1}{2} \cdot \frac{y}{{x}^{2}}\right)} \]
    4. Step-by-step derivation
      1. distribute-lft-inN/A

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

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

        \[\leadsto \mathsf{+.f64}\left(x, \color{blue}{\left(x \cdot \left(\frac{1}{2} \cdot \frac{y}{{x}^{2}}\right)\right)}\right) \]
      4. *-commutativeN/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\left(\frac{1}{2} \cdot \frac{y}{{x}^{2}}\right) \cdot \color{blue}{x}\right)\right) \]
      5. associate-*l*N/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \color{blue}{\left(\frac{y}{{x}^{2}} \cdot x\right)}\right)\right) \]
      6. associate-*l/N/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y \cdot x}{\color{blue}{{x}^{2}}}\right)\right) \]
      7. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y \cdot x}{x \cdot \color{blue}{x}}\right)\right) \]
      8. times-fracN/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \left(\frac{y}{x} \cdot \color{blue}{\frac{x}{x}}\right)\right)\right) \]
      9. *-inversesN/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \left(\frac{y}{x} \cdot 1\right)\right)\right) \]
      10. *-rgt-identityN/A

        \[\leadsto \mathsf{+.f64}\left(x, \left(\frac{1}{2} \cdot \frac{y}{\color{blue}{x}}\right)\right) \]
      11. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(x, \mathsf{*.f64}\left(\frac{1}{2}, \color{blue}{\left(\frac{y}{x}\right)}\right)\right) \]
      12. /-lowering-/.f6432.3%

        \[\leadsto \mathsf{+.f64}\left(x, \mathsf{*.f64}\left(\frac{1}{2}, \mathsf{/.f64}\left(y, \color{blue}{x}\right)\right)\right) \]
    5. Simplified32.3%

      \[\leadsto \color{blue}{x + 0.5 \cdot \frac{y}{x}} \]
    6. Add Preprocessing

    Alternative 4: 68.2% accurate, 105.0× speedup?

    \[\begin{array}{l} x_m = \left|x\right| \\ x\_m \end{array} \]
    x_m = (fabs.f64 x)
    (FPCore (x_m y) :precision binary64 x_m)
    x_m = fabs(x);
    double code(double x_m, double y) {
    	return x_m;
    }
    
    x_m = abs(x)
    real(8) function code(x_m, y)
        real(8), intent (in) :: x_m
        real(8), intent (in) :: y
        code = x_m
    end function
    
    x_m = Math.abs(x);
    public static double code(double x_m, double y) {
    	return x_m;
    }
    
    x_m = math.fabs(x)
    def code(x_m, y):
    	return x_m
    
    x_m = abs(x)
    function code(x_m, y)
    	return x_m
    end
    
    x_m = abs(x);
    function tmp = code(x_m, y)
    	tmp = x_m;
    end
    
    x_m = N[Abs[x], $MachinePrecision]
    code[x$95$m_, y_] := x$95$m
    
    \begin{array}{l}
    x_m = \left|x\right|
    
    \\
    x\_m
    \end{array}
    
    Derivation
    1. Initial program 68.9%

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

      \[\leadsto \color{blue}{x} \]
    4. Step-by-step derivation
      1. Simplified32.0%

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

      Developer Target 1: 98.4% accurate, 0.9× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_0 := 0.5 \cdot \frac{y}{x} + x\\ \mathbf{if}\;x < -1.5097698010472593 \cdot 10^{+153}:\\ \;\;\;\;-t\_0\\ \mathbf{elif}\;x < 5.582399551122541 \cdot 10^{+57}:\\ \;\;\;\;\sqrt{x \cdot x + y}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
      (FPCore (x y)
       :precision binary64
       (let* ((t_0 (+ (* 0.5 (/ y x)) x)))
         (if (< x -1.5097698010472593e+153)
           (- t_0)
           (if (< x 5.582399551122541e+57) (sqrt (+ (* x x) y)) t_0))))
      double code(double x, double y) {
      	double t_0 = (0.5 * (y / x)) + x;
      	double tmp;
      	if (x < -1.5097698010472593e+153) {
      		tmp = -t_0;
      	} else if (x < 5.582399551122541e+57) {
      		tmp = sqrt(((x * x) + y));
      	} else {
      		tmp = t_0;
      	}
      	return tmp;
      }
      
      real(8) function code(x, y)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          real(8) :: t_0
          real(8) :: tmp
          t_0 = (0.5d0 * (y / x)) + x
          if (x < (-1.5097698010472593d+153)) then
              tmp = -t_0
          else if (x < 5.582399551122541d+57) then
              tmp = sqrt(((x * x) + y))
          else
              tmp = t_0
          end if
          code = tmp
      end function
      
      public static double code(double x, double y) {
      	double t_0 = (0.5 * (y / x)) + x;
      	double tmp;
      	if (x < -1.5097698010472593e+153) {
      		tmp = -t_0;
      	} else if (x < 5.582399551122541e+57) {
      		tmp = Math.sqrt(((x * x) + y));
      	} else {
      		tmp = t_0;
      	}
      	return tmp;
      }
      
      def code(x, y):
      	t_0 = (0.5 * (y / x)) + x
      	tmp = 0
      	if x < -1.5097698010472593e+153:
      		tmp = -t_0
      	elif x < 5.582399551122541e+57:
      		tmp = math.sqrt(((x * x) + y))
      	else:
      		tmp = t_0
      	return tmp
      
      function code(x, y)
      	t_0 = Float64(Float64(0.5 * Float64(y / x)) + x)
      	tmp = 0.0
      	if (x < -1.5097698010472593e+153)
      		tmp = Float64(-t_0);
      	elseif (x < 5.582399551122541e+57)
      		tmp = sqrt(Float64(Float64(x * x) + y));
      	else
      		tmp = t_0;
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y)
      	t_0 = (0.5 * (y / x)) + x;
      	tmp = 0.0;
      	if (x < -1.5097698010472593e+153)
      		tmp = -t_0;
      	elseif (x < 5.582399551122541e+57)
      		tmp = sqrt(((x * x) + y));
      	else
      		tmp = t_0;
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_] := Block[{t$95$0 = N[(N[(0.5 * N[(y / x), $MachinePrecision]), $MachinePrecision] + x), $MachinePrecision]}, If[Less[x, -1.5097698010472593e+153], (-t$95$0), If[Less[x, 5.582399551122541e+57], N[Sqrt[N[(N[(x * x), $MachinePrecision] + y), $MachinePrecision]], $MachinePrecision], t$95$0]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_0 := 0.5 \cdot \frac{y}{x} + x\\
      \mathbf{if}\;x < -1.5097698010472593 \cdot 10^{+153}:\\
      \;\;\;\;-t\_0\\
      
      \mathbf{elif}\;x < 5.582399551122541 \cdot 10^{+57}:\\
      \;\;\;\;\sqrt{x \cdot x + y}\\
      
      \mathbf{else}:\\
      \;\;\;\;t\_0\\
      
      
      \end{array}
      \end{array}
      

      Reproduce

      ?
      herbie shell --seed 2024192 
      (FPCore (x y)
        :name "Linear.Quaternion:$clog from linear-1.19.1.3"
        :precision binary64
      
        :alt
        (! :herbie-platform default (if (< x -1509769801047259300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (- (+ (* 1/2 (/ y x)) x)) (if (< x 5582399551122541000000000000000000000000000000000000000000) (sqrt (+ (* x x) y)) (+ (* 1/2 (/ y x)) x))))
      
        (sqrt (+ (* x x) y)))