Linear.Projection:perspective from linear-1.19.1.3, A

Percentage Accurate: 100.0% → 100.0%
Time: 9.0s
Alternatives: 7
Speedup: 1.0×

Specification

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

\\
\frac{x + y}{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 7 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: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{x + y}{x - y} \end{array} \]
(FPCore (x y) :precision binary64 (/ (+ x y) (- x y)))
double code(double x, double y) {
	return (x + y) / (x - y);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (x + y) / (x - y)
end function
public static double code(double x, double y) {
	return (x + y) / (x - y);
}
def code(x, y):
	return (x + y) / (x - y)
function code(x, y)
	return Float64(Float64(x + y) / Float64(x - y))
end
function tmp = code(x, y)
	tmp = (x + y) / (x - y);
end
code[x_, y_] := N[(N[(x + y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{x + y}{x - y}
\end{array}

Alternative 1: 100.0% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \frac{y}{x - y} + \frac{x}{x - y} \end{array} \]
(FPCore (x y) :precision binary64 (+ (/ y (- x y)) (/ x (- x y))))
double code(double x, double y) {
	return (y / (x - y)) + (x / (x - y));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (y / (x - y)) + (x / (x - y))
end function
public static double code(double x, double y) {
	return (y / (x - y)) + (x / (x - y));
}
def code(x, y):
	return (y / (x - y)) + (x / (x - y))
function code(x, y)
	return Float64(Float64(y / Float64(x - y)) + Float64(x / Float64(x - y)))
end
function tmp = code(x, y)
	tmp = (y / (x - y)) + (x / (x - y));
end
code[x_, y_] := N[(N[(y / N[(x - y), $MachinePrecision]), $MachinePrecision] + N[(x / N[(x - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{y}{x - y} + \frac{x}{x - y}
\end{array}
Derivation
  1. Initial program 99.9%

    \[\frac{x + y}{x - y} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. div-invN/A

      \[\leadsto \color{blue}{\left(x + y\right) \cdot \frac{1}{x - y}} \]
    2. flip3--N/A

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

      \[\leadsto \left(x + y\right) \cdot \color{blue}{\frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}}} \]
    4. *-commutativeN/A

      \[\leadsto \color{blue}{\frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}} \cdot \left(x + y\right)} \]
    5. distribute-lft-inN/A

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}}, x, \frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}} \cdot y\right)} \]
    7. clear-numN/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{1}{\frac{{x}^{3} - {y}^{3}}{x \cdot x + \left(y \cdot y + x \cdot y\right)}}}, x, \frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}} \cdot y\right) \]
    8. flip3--N/A

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

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

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

      \[\leadsto \mathsf{fma}\left(\frac{1}{x - y}, x, \color{blue}{\frac{x \cdot x + \left(y \cdot y + x \cdot y\right)}{{x}^{3} - {y}^{3}} \cdot y}\right) \]
  4. Applied egg-rr99.8%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{x - y}, x, \frac{1}{x - y} \cdot y\right)} \]
  5. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \color{blue}{\frac{1}{x - y} \cdot y + \frac{1}{x - y} \cdot x} \]
    2. +-lowering-+.f64N/A

      \[\leadsto \color{blue}{\frac{1}{x - y} \cdot y + \frac{1}{x - y} \cdot x} \]
    3. *-commutativeN/A

      \[\leadsto \color{blue}{y \cdot \frac{1}{x - y}} + \frac{1}{x - y} \cdot x \]
    4. div-invN/A

      \[\leadsto \color{blue}{\frac{y}{x - y}} + \frac{1}{x - y} \cdot x \]
    5. /-lowering-/.f64N/A

      \[\leadsto \color{blue}{\frac{y}{x - y}} + \frac{1}{x - y} \cdot x \]
    6. --lowering--.f64N/A

      \[\leadsto \frac{y}{\color{blue}{x - y}} + \frac{1}{x - y} \cdot x \]
    7. *-commutativeN/A

      \[\leadsto \frac{y}{x - y} + \color{blue}{x \cdot \frac{1}{x - y}} \]
    8. un-div-invN/A

      \[\leadsto \frac{y}{x - y} + \color{blue}{\frac{x}{x - y}} \]
    9. /-lowering-/.f64N/A

      \[\leadsto \frac{y}{x - y} + \color{blue}{\frac{x}{x - y}} \]
    10. --lowering--.f64100.0

      \[\leadsto \frac{y}{x - y} + \frac{x}{\color{blue}{x - y}} \]
  6. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\frac{y}{x - y} + \frac{x}{x - y}} \]
  7. Add Preprocessing

Alternative 2: 97.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1 - \frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;\frac{y + x}{x}\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (/ (+ y x) (- x y)) -0.4) (- -1.0 (/ x y)) (/ (+ y x) x)))
double code(double x, double y) {
	double tmp;
	if (((y + x) / (x - y)) <= -0.4) {
		tmp = -1.0 - (x / y);
	} else {
		tmp = (y + x) / x;
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (((y + x) / (x - y)) <= (-0.4d0)) then
        tmp = (-1.0d0) - (x / y)
    else
        tmp = (y + x) / x
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if (((y + x) / (x - y)) <= -0.4) {
		tmp = -1.0 - (x / y);
	} else {
		tmp = (y + x) / x;
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if ((y + x) / (x - y)) <= -0.4:
		tmp = -1.0 - (x / y)
	else:
		tmp = (y + x) / x
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64(Float64(y + x) / Float64(x - y)) <= -0.4)
		tmp = Float64(-1.0 - Float64(x / y));
	else
		tmp = Float64(Float64(y + x) / x);
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (((y + x) / (x - y)) <= -0.4)
		tmp = -1.0 - (x / y);
	else
		tmp = (y + x) / x;
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[N[(N[(y + x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision], -0.4], N[(-1.0 - N[(x / y), $MachinePrecision]), $MachinePrecision], N[(N[(y + x), $MachinePrecision] / x), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\
\;\;\;\;-1 - \frac{x}{y}\\

\mathbf{else}:\\
\;\;\;\;\frac{y + x}{x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (+.f64 x y) (-.f64 x y)) < -0.40000000000000002

    1. Initial program 100.0%

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

      \[\leadsto \frac{\color{blue}{y}}{x - y} \]
    4. Step-by-step derivation
      1. Simplified97.6%

        \[\leadsto \frac{\color{blue}{y}}{x - y} \]
      2. Taylor expanded in y around inf

        \[\leadsto \color{blue}{-1 \cdot \frac{x}{y} - 1} \]
      3. Step-by-step derivation
        1. sub-negN/A

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

          \[\leadsto -1 \cdot \frac{x}{y} + \color{blue}{-1} \]
        3. +-commutativeN/A

          \[\leadsto \color{blue}{-1 + -1 \cdot \frac{x}{y}} \]
        4. mul-1-negN/A

          \[\leadsto -1 + \color{blue}{\left(\mathsf{neg}\left(\frac{x}{y}\right)\right)} \]
        5. sub-negN/A

          \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]
        6. --lowering--.f64N/A

          \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]
        7. /-lowering-/.f6497.7

          \[\leadsto -1 - \color{blue}{\frac{x}{y}} \]
      4. Simplified97.7%

        \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]

      if -0.40000000000000002 < (/.f64 (+.f64 x y) (-.f64 x y))

      1. Initial program 99.9%

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

        \[\leadsto \frac{x + y}{\color{blue}{x}} \]
      4. Step-by-step derivation
        1. Simplified99.0%

          \[\leadsto \frac{x + y}{\color{blue}{x}} \]
      5. Recombined 2 regimes into one program.
      6. Final simplification98.3%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1 - \frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;\frac{y + x}{x}\\ \end{array} \]
      7. Add Preprocessing

      Alternative 3: 97.8% accurate, 0.5× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1 - \frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;1 + \frac{y}{x}\\ \end{array} \end{array} \]
      (FPCore (x y)
       :precision binary64
       (if (<= (/ (+ y x) (- x y)) -0.4) (- -1.0 (/ x y)) (+ 1.0 (/ y x))))
      double code(double x, double y) {
      	double tmp;
      	if (((y + x) / (x - y)) <= -0.4) {
      		tmp = -1.0 - (x / y);
      	} else {
      		tmp = 1.0 + (y / x);
      	}
      	return tmp;
      }
      
      real(8) function code(x, y)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          real(8) :: tmp
          if (((y + x) / (x - y)) <= (-0.4d0)) then
              tmp = (-1.0d0) - (x / y)
          else
              tmp = 1.0d0 + (y / x)
          end if
          code = tmp
      end function
      
      public static double code(double x, double y) {
      	double tmp;
      	if (((y + x) / (x - y)) <= -0.4) {
      		tmp = -1.0 - (x / y);
      	} else {
      		tmp = 1.0 + (y / x);
      	}
      	return tmp;
      }
      
      def code(x, y):
      	tmp = 0
      	if ((y + x) / (x - y)) <= -0.4:
      		tmp = -1.0 - (x / y)
      	else:
      		tmp = 1.0 + (y / x)
      	return tmp
      
      function code(x, y)
      	tmp = 0.0
      	if (Float64(Float64(y + x) / Float64(x - y)) <= -0.4)
      		tmp = Float64(-1.0 - Float64(x / y));
      	else
      		tmp = Float64(1.0 + Float64(y / x));
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y)
      	tmp = 0.0;
      	if (((y + x) / (x - y)) <= -0.4)
      		tmp = -1.0 - (x / y);
      	else
      		tmp = 1.0 + (y / x);
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_] := If[LessEqual[N[(N[(y + x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision], -0.4], N[(-1.0 - N[(x / y), $MachinePrecision]), $MachinePrecision], N[(1.0 + N[(y / x), $MachinePrecision]), $MachinePrecision]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\
      \;\;\;\;-1 - \frac{x}{y}\\
      
      \mathbf{else}:\\
      \;\;\;\;1 + \frac{y}{x}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (/.f64 (+.f64 x y) (-.f64 x y)) < -0.40000000000000002

        1. Initial program 100.0%

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

          \[\leadsto \frac{\color{blue}{y}}{x - y} \]
        4. Step-by-step derivation
          1. Simplified97.6%

            \[\leadsto \frac{\color{blue}{y}}{x - y} \]
          2. Taylor expanded in y around inf

            \[\leadsto \color{blue}{-1 \cdot \frac{x}{y} - 1} \]
          3. Step-by-step derivation
            1. sub-negN/A

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

              \[\leadsto -1 \cdot \frac{x}{y} + \color{blue}{-1} \]
            3. +-commutativeN/A

              \[\leadsto \color{blue}{-1 + -1 \cdot \frac{x}{y}} \]
            4. mul-1-negN/A

              \[\leadsto -1 + \color{blue}{\left(\mathsf{neg}\left(\frac{x}{y}\right)\right)} \]
            5. sub-negN/A

              \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]
            6. --lowering--.f64N/A

              \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]
            7. /-lowering-/.f6497.7

              \[\leadsto -1 - \color{blue}{\frac{x}{y}} \]
          4. Simplified97.7%

            \[\leadsto \color{blue}{-1 - \frac{x}{y}} \]

          if -0.40000000000000002 < (/.f64 (+.f64 x y) (-.f64 x y))

          1. Initial program 99.9%

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

            \[\leadsto \frac{x + y}{\color{blue}{x}} \]
          4. Step-by-step derivation
            1. Simplified99.0%

              \[\leadsto \frac{x + y}{\color{blue}{x}} \]
            2. Taylor expanded in x around inf

              \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
            3. Step-by-step derivation
              1. +-lowering-+.f64N/A

                \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
              2. /-lowering-/.f6499.0

                \[\leadsto 1 + \color{blue}{\frac{y}{x}} \]
            4. Simplified99.0%

              \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
          5. Recombined 2 regimes into one program.
          6. Final simplification98.3%

            \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1 - \frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;1 + \frac{y}{x}\\ \end{array} \]
          7. Add Preprocessing

          Alternative 4: 97.8% accurate, 0.5× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1\\ \mathbf{else}:\\ \;\;\;\;1 + \frac{y}{x}\\ \end{array} \end{array} \]
          (FPCore (x y)
           :precision binary64
           (if (<= (/ (+ y x) (- x y)) -0.4) -1.0 (+ 1.0 (/ y x))))
          double code(double x, double y) {
          	double tmp;
          	if (((y + x) / (x - y)) <= -0.4) {
          		tmp = -1.0;
          	} else {
          		tmp = 1.0 + (y / x);
          	}
          	return tmp;
          }
          
          real(8) function code(x, y)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              real(8) :: tmp
              if (((y + x) / (x - y)) <= (-0.4d0)) then
                  tmp = -1.0d0
              else
                  tmp = 1.0d0 + (y / x)
              end if
              code = tmp
          end function
          
          public static double code(double x, double y) {
          	double tmp;
          	if (((y + x) / (x - y)) <= -0.4) {
          		tmp = -1.0;
          	} else {
          		tmp = 1.0 + (y / x);
          	}
          	return tmp;
          }
          
          def code(x, y):
          	tmp = 0
          	if ((y + x) / (x - y)) <= -0.4:
          		tmp = -1.0
          	else:
          		tmp = 1.0 + (y / x)
          	return tmp
          
          function code(x, y)
          	tmp = 0.0
          	if (Float64(Float64(y + x) / Float64(x - y)) <= -0.4)
          		tmp = -1.0;
          	else
          		tmp = Float64(1.0 + Float64(y / x));
          	end
          	return tmp
          end
          
          function tmp_2 = code(x, y)
          	tmp = 0.0;
          	if (((y + x) / (x - y)) <= -0.4)
          		tmp = -1.0;
          	else
          		tmp = 1.0 + (y / x);
          	end
          	tmp_2 = tmp;
          end
          
          code[x_, y_] := If[LessEqual[N[(N[(y + x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision], -0.4], -1.0, N[(1.0 + N[(y / x), $MachinePrecision]), $MachinePrecision]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\
          \;\;\;\;-1\\
          
          \mathbf{else}:\\
          \;\;\;\;1 + \frac{y}{x}\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if (/.f64 (+.f64 x y) (-.f64 x y)) < -0.40000000000000002

            1. Initial program 100.0%

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

              \[\leadsto \color{blue}{-1} \]
            4. Step-by-step derivation
              1. Simplified97.6%

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

              if -0.40000000000000002 < (/.f64 (+.f64 x y) (-.f64 x y))

              1. Initial program 99.9%

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

                \[\leadsto \frac{x + y}{\color{blue}{x}} \]
              4. Step-by-step derivation
                1. Simplified99.0%

                  \[\leadsto \frac{x + y}{\color{blue}{x}} \]
                2. Taylor expanded in x around inf

                  \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
                3. Step-by-step derivation
                  1. +-lowering-+.f64N/A

                    \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
                  2. /-lowering-/.f6499.0

                    \[\leadsto 1 + \color{blue}{\frac{y}{x}} \]
                4. Simplified99.0%

                  \[\leadsto \color{blue}{1 + \frac{y}{x}} \]
              5. Recombined 2 regimes into one program.
              6. Final simplification98.3%

                \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -0.4:\\ \;\;\;\;-1\\ \mathbf{else}:\\ \;\;\;\;1 + \frac{y}{x}\\ \end{array} \]
              7. Add Preprocessing

              Alternative 5: 97.8% accurate, 0.7× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -1 \cdot 10^{-309}:\\ \;\;\;\;-1\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]
              (FPCore (x y)
               :precision binary64
               (if (<= (/ (+ y x) (- x y)) -1e-309) -1.0 1.0))
              double code(double x, double y) {
              	double tmp;
              	if (((y + x) / (x - y)) <= -1e-309) {
              		tmp = -1.0;
              	} else {
              		tmp = 1.0;
              	}
              	return tmp;
              }
              
              real(8) function code(x, y)
                  real(8), intent (in) :: x
                  real(8), intent (in) :: y
                  real(8) :: tmp
                  if (((y + x) / (x - y)) <= (-1d-309)) then
                      tmp = -1.0d0
                  else
                      tmp = 1.0d0
                  end if
                  code = tmp
              end function
              
              public static double code(double x, double y) {
              	double tmp;
              	if (((y + x) / (x - y)) <= -1e-309) {
              		tmp = -1.0;
              	} else {
              		tmp = 1.0;
              	}
              	return tmp;
              }
              
              def code(x, y):
              	tmp = 0
              	if ((y + x) / (x - y)) <= -1e-309:
              		tmp = -1.0
              	else:
              		tmp = 1.0
              	return tmp
              
              function code(x, y)
              	tmp = 0.0
              	if (Float64(Float64(y + x) / Float64(x - y)) <= -1e-309)
              		tmp = -1.0;
              	else
              		tmp = 1.0;
              	end
              	return tmp
              end
              
              function tmp_2 = code(x, y)
              	tmp = 0.0;
              	if (((y + x) / (x - y)) <= -1e-309)
              		tmp = -1.0;
              	else
              		tmp = 1.0;
              	end
              	tmp_2 = tmp;
              end
              
              code[x_, y_] := If[LessEqual[N[(N[(y + x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision], -1e-309], -1.0, 1.0]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              \mathbf{if}\;\frac{y + x}{x - y} \leq -1 \cdot 10^{-309}:\\
              \;\;\;\;-1\\
              
              \mathbf{else}:\\
              \;\;\;\;1\\
              
              
              \end{array}
              \end{array}
              
              Derivation
              1. Split input into 2 regimes
              2. if (/.f64 (+.f64 x y) (-.f64 x y)) < -1.000000000000002e-309

                1. Initial program 100.0%

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

                  \[\leadsto \color{blue}{-1} \]
                4. Step-by-step derivation
                  1. Simplified97.6%

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

                  if -1.000000000000002e-309 < (/.f64 (+.f64 x y) (-.f64 x y))

                  1. Initial program 99.9%

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

                    \[\leadsto \color{blue}{1} \]
                  4. Step-by-step derivation
                    1. Simplified98.9%

                      \[\leadsto \color{blue}{1} \]
                  5. Recombined 2 regimes into one program.
                  6. Final simplification98.3%

                    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{y + x}{x - y} \leq -1 \cdot 10^{-309}:\\ \;\;\;\;-1\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \]
                  7. Add Preprocessing

                  Alternative 6: 100.0% accurate, 1.0× speedup?

                  \[\begin{array}{l} \\ \frac{y + x}{x - y} \end{array} \]
                  (FPCore (x y) :precision binary64 (/ (+ y x) (- x y)))
                  double code(double x, double y) {
                  	return (y + x) / (x - y);
                  }
                  
                  real(8) function code(x, y)
                      real(8), intent (in) :: x
                      real(8), intent (in) :: y
                      code = (y + x) / (x - y)
                  end function
                  
                  public static double code(double x, double y) {
                  	return (y + x) / (x - y);
                  }
                  
                  def code(x, y):
                  	return (y + x) / (x - y)
                  
                  function code(x, y)
                  	return Float64(Float64(y + x) / Float64(x - y))
                  end
                  
                  function tmp = code(x, y)
                  	tmp = (y + x) / (x - y);
                  end
                  
                  code[x_, y_] := N[(N[(y + x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]
                  
                  \begin{array}{l}
                  
                  \\
                  \frac{y + x}{x - y}
                  \end{array}
                  
                  Derivation
                  1. Initial program 99.9%

                    \[\frac{x + y}{x - y} \]
                  2. Add Preprocessing
                  3. Final simplification99.9%

                    \[\leadsto \frac{y + x}{x - y} \]
                  4. Add Preprocessing

                  Alternative 7: 48.1% accurate, 18.0× speedup?

                  \[\begin{array}{l} \\ -1 \end{array} \]
                  (FPCore (x y) :precision binary64 -1.0)
                  double code(double x, double y) {
                  	return -1.0;
                  }
                  
                  real(8) function code(x, y)
                      real(8), intent (in) :: x
                      real(8), intent (in) :: y
                      code = -1.0d0
                  end function
                  
                  public static double code(double x, double y) {
                  	return -1.0;
                  }
                  
                  def code(x, y):
                  	return -1.0
                  
                  function code(x, y)
                  	return -1.0
                  end
                  
                  function tmp = code(x, y)
                  	tmp = -1.0;
                  end
                  
                  code[x_, y_] := -1.0
                  
                  \begin{array}{l}
                  
                  \\
                  -1
                  \end{array}
                  
                  Derivation
                  1. Initial program 99.9%

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

                    \[\leadsto \color{blue}{-1} \]
                  4. Step-by-step derivation
                    1. Simplified48.8%

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

                    Developer Target 1: 100.0% accurate, 0.4× speedup?

                    \[\begin{array}{l} \\ \frac{1}{\frac{x}{x + y} - \frac{y}{x + y}} \end{array} \]
                    (FPCore (x y) :precision binary64 (/ 1.0 (- (/ x (+ x y)) (/ y (+ x y)))))
                    double code(double x, double y) {
                    	return 1.0 / ((x / (x + y)) - (y / (x + y)));
                    }
                    
                    real(8) function code(x, y)
                        real(8), intent (in) :: x
                        real(8), intent (in) :: y
                        code = 1.0d0 / ((x / (x + y)) - (y / (x + y)))
                    end function
                    
                    public static double code(double x, double y) {
                    	return 1.0 / ((x / (x + y)) - (y / (x + y)));
                    }
                    
                    def code(x, y):
                    	return 1.0 / ((x / (x + y)) - (y / (x + y)))
                    
                    function code(x, y)
                    	return Float64(1.0 / Float64(Float64(x / Float64(x + y)) - Float64(y / Float64(x + y))))
                    end
                    
                    function tmp = code(x, y)
                    	tmp = 1.0 / ((x / (x + y)) - (y / (x + y)));
                    end
                    
                    code[x_, y_] := N[(1.0 / N[(N[(x / N[(x + y), $MachinePrecision]), $MachinePrecision] - N[(y / N[(x + y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
                    
                    \begin{array}{l}
                    
                    \\
                    \frac{1}{\frac{x}{x + y} - \frac{y}{x + y}}
                    \end{array}
                    

                    Reproduce

                    ?
                    herbie shell --seed 2024196 
                    (FPCore (x y)
                      :name "Linear.Projection:perspective from linear-1.19.1.3, A"
                      :precision binary64
                    
                      :alt
                      (! :herbie-platform default (/ 1 (- (/ x (+ x y)) (/ y (+ x y)))))
                    
                      (/ (+ x y) (- x y)))