Numeric.SpecFunctions:log1p from math-functions-0.1.5.2, A

Percentage Accurate: 99.9% → 99.9%
Time: 8.1s
Alternatives: 8
Speedup: 1.0×

Specification

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

\\
x \cdot \left(1 - x \cdot y\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 8 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: 99.9% accurate, 1.0× speedup?

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

\\
x \cdot \left(1 - x \cdot y\right)
\end{array}

Alternative 1: 99.9% accurate, 1.0× speedup?

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

\\
x \cdot \left(1 - x \cdot y\right)
\end{array}
Derivation
  1. Initial program 99.9%

    \[x \cdot \left(1 - x \cdot y\right) \]
  2. Add Preprocessing
  3. Add Preprocessing

Alternative 2: 80.5% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot \left(1 - x \cdot y\right)\\ t_1 := x \cdot \left(y \cdot \left(-x\right)\right)\\ \mathbf{if}\;t\_0 \leq -2 \cdot 10^{+262}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t\_0 \leq 10^{+103}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (* x (- 1.0 (* x y)))) (t_1 (* x (* y (- x)))))
   (if (<= t_0 -2e+262) t_1 (if (<= t_0 1e+103) (* x 1.0) t_1))))
double code(double x, double y) {
	double t_0 = x * (1.0 - (x * y));
	double t_1 = x * (y * -x);
	double tmp;
	if (t_0 <= -2e+262) {
		tmp = t_1;
	} else if (t_0 <= 1e+103) {
		tmp = x * 1.0;
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = x * (1.0d0 - (x * y))
    t_1 = x * (y * -x)
    if (t_0 <= (-2d+262)) then
        tmp = t_1
    else if (t_0 <= 1d+103) then
        tmp = x * 1.0d0
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double t_0 = x * (1.0 - (x * y));
	double t_1 = x * (y * -x);
	double tmp;
	if (t_0 <= -2e+262) {
		tmp = t_1;
	} else if (t_0 <= 1e+103) {
		tmp = x * 1.0;
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(x, y):
	t_0 = x * (1.0 - (x * y))
	t_1 = x * (y * -x)
	tmp = 0
	if t_0 <= -2e+262:
		tmp = t_1
	elif t_0 <= 1e+103:
		tmp = x * 1.0
	else:
		tmp = t_1
	return tmp
function code(x, y)
	t_0 = Float64(x * Float64(1.0 - Float64(x * y)))
	t_1 = Float64(x * Float64(y * Float64(-x)))
	tmp = 0.0
	if (t_0 <= -2e+262)
		tmp = t_1;
	elseif (t_0 <= 1e+103)
		tmp = Float64(x * 1.0);
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(x, y)
	t_0 = x * (1.0 - (x * y));
	t_1 = x * (y * -x);
	tmp = 0.0;
	if (t_0 <= -2e+262)
		tmp = t_1;
	elseif (t_0 <= 1e+103)
		tmp = x * 1.0;
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[x_, y_] := Block[{t$95$0 = N[(x * N[(1.0 - N[(x * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(x * N[(y * (-x)), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -2e+262], t$95$1, If[LessEqual[t$95$0, 1e+103], N[(x * 1.0), $MachinePrecision], t$95$1]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot \left(1 - x \cdot y\right)\\
t_1 := x \cdot \left(y \cdot \left(-x\right)\right)\\
\mathbf{if}\;t\_0 \leq -2 \cdot 10^{+262}:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t\_0 \leq 10^{+103}:\\
\;\;\;\;x \cdot 1\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < -2e262 or 1e103 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y)))

    1. Initial program 99.9%

      \[x \cdot \left(1 - x \cdot y\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

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

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

        \[\leadsto x \cdot \color{blue}{\left(\mathsf{neg}\left(x \cdot y\right)\right)} \]
      3. lower-*.f6492.6

        \[\leadsto x \cdot \left(-\color{blue}{x \cdot y}\right) \]
    5. Applied rewrites92.6%

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

    if -2e262 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < 1e103

    1. Initial program 99.9%

      \[x \cdot \left(1 - x \cdot y\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto x \cdot \color{blue}{1} \]
    4. Step-by-step derivation
      1. Applied rewrites84.1%

        \[\leadsto x \cdot \color{blue}{1} \]
    5. Recombined 2 regimes into one program.
    6. Final simplification87.6%

      \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -2 \cdot 10^{+262}:\\ \;\;\;\;x \cdot \left(y \cdot \left(-x\right)\right)\\ \mathbf{elif}\;x \cdot \left(1 - x \cdot y\right) \leq 10^{+103}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(y \cdot \left(-x\right)\right)\\ \end{array} \]
    7. Add Preprocessing

    Alternative 3: 62.9% accurate, 0.3× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot \left(1 - x \cdot y\right)\\ \mathbf{if}\;t\_0 \leq -5 \cdot 10^{+266}:\\ \;\;\;\;y \cdot \left(-x\right)\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+222}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \end{array} \]
    (FPCore (x y)
     :precision binary64
     (let* ((t_0 (* x (- 1.0 (* x y)))))
       (if (<= t_0 -5e+266) (* y (- x)) (if (<= t_0 5e+222) (* x 1.0) (* x x)))))
    double code(double x, double y) {
    	double t_0 = x * (1.0 - (x * y));
    	double tmp;
    	if (t_0 <= -5e+266) {
    		tmp = y * -x;
    	} else if (t_0 <= 5e+222) {
    		tmp = x * 1.0;
    	} else {
    		tmp = x * x;
    	}
    	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 = x * (1.0d0 - (x * y))
        if (t_0 <= (-5d+266)) then
            tmp = y * -x
        else if (t_0 <= 5d+222) then
            tmp = x * 1.0d0
        else
            tmp = x * x
        end if
        code = tmp
    end function
    
    public static double code(double x, double y) {
    	double t_0 = x * (1.0 - (x * y));
    	double tmp;
    	if (t_0 <= -5e+266) {
    		tmp = y * -x;
    	} else if (t_0 <= 5e+222) {
    		tmp = x * 1.0;
    	} else {
    		tmp = x * x;
    	}
    	return tmp;
    }
    
    def code(x, y):
    	t_0 = x * (1.0 - (x * y))
    	tmp = 0
    	if t_0 <= -5e+266:
    		tmp = y * -x
    	elif t_0 <= 5e+222:
    		tmp = x * 1.0
    	else:
    		tmp = x * x
    	return tmp
    
    function code(x, y)
    	t_0 = Float64(x * Float64(1.0 - Float64(x * y)))
    	tmp = 0.0
    	if (t_0 <= -5e+266)
    		tmp = Float64(y * Float64(-x));
    	elseif (t_0 <= 5e+222)
    		tmp = Float64(x * 1.0);
    	else
    		tmp = Float64(x * x);
    	end
    	return tmp
    end
    
    function tmp_2 = code(x, y)
    	t_0 = x * (1.0 - (x * y));
    	tmp = 0.0;
    	if (t_0 <= -5e+266)
    		tmp = y * -x;
    	elseif (t_0 <= 5e+222)
    		tmp = x * 1.0;
    	else
    		tmp = x * x;
    	end
    	tmp_2 = tmp;
    end
    
    code[x_, y_] := Block[{t$95$0 = N[(x * N[(1.0 - N[(x * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -5e+266], N[(y * (-x)), $MachinePrecision], If[LessEqual[t$95$0, 5e+222], N[(x * 1.0), $MachinePrecision], N[(x * x), $MachinePrecision]]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := x \cdot \left(1 - x \cdot y\right)\\
    \mathbf{if}\;t\_0 \leq -5 \cdot 10^{+266}:\\
    \;\;\;\;y \cdot \left(-x\right)\\
    
    \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+222}:\\
    \;\;\;\;x \cdot 1\\
    
    \mathbf{else}:\\
    \;\;\;\;x \cdot x\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < -4.9999999999999999e266

      1. Initial program 99.9%

        \[x \cdot \left(1 - x \cdot y\right) \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

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

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

          \[\leadsto \color{blue}{\mathsf{neg}\left(x \cdot y\right)} \]
        3. lower-*.f6423.8

          \[\leadsto -\color{blue}{x \cdot y} \]
      5. Applied rewrites23.8%

        \[\leadsto \color{blue}{-x \cdot y} \]

      if -4.9999999999999999e266 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < 5.00000000000000023e222

      1. Initial program 99.9%

        \[x \cdot \left(1 - x \cdot y\right) \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto x \cdot \color{blue}{1} \]
      4. Step-by-step derivation
        1. Applied rewrites79.8%

          \[\leadsto x \cdot \color{blue}{1} \]

        if 5.00000000000000023e222 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y)))

        1. Initial program 100.0%

          \[x \cdot \left(1 - x \cdot y\right) \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift-*.f64N/A

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

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

            \[\leadsto x \cdot \color{blue}{\left(1 + \left(\mathsf{neg}\left(x \cdot y\right)\right)\right)} \]
          4. +-commutativeN/A

            \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x \cdot y\right)\right) + 1\right)} \]
          5. distribute-lft-inN/A

            \[\leadsto \color{blue}{x \cdot \left(\mathsf{neg}\left(x \cdot y\right)\right) + x \cdot 1} \]
          6. lift-*.f64N/A

            \[\leadsto x \cdot \left(\mathsf{neg}\left(\color{blue}{x \cdot y}\right)\right) + x \cdot 1 \]
          7. distribute-lft-neg-inN/A

            \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x\right)\right) \cdot y\right)} + x \cdot 1 \]
          8. associate-*r*N/A

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

            \[\leadsto \left(x \cdot \left(\mathsf{neg}\left(x\right)\right)\right) \cdot y + \color{blue}{x} \]
          10. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(\mathsf{neg}\left(x\right)\right), y, x\right)} \]
          11. lower-*.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot \left(\mathsf{neg}\left(x\right)\right)}, y, x\right) \]
          12. lower-neg.f6495.6

            \[\leadsto \mathsf{fma}\left(x \cdot \color{blue}{\left(-x\right)}, y, x\right) \]
        4. Applied rewrites95.6%

          \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(-x\right), y, x\right)} \]
        5. Applied rewrites0.6%

          \[\leadsto \color{blue}{\frac{x \cdot \left(x \cdot \left(x \cdot y\right)\right) - x \cdot \left(y \cdot \left(x \cdot \left(x \cdot \left(x \cdot y\right)\right)\right)\right)}{x \cdot \left(x \cdot y\right)}} \]
        6. Taylor expanded in y around inf

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

            \[\leadsto \color{blue}{x \cdot x} \]
          2. lower-*.f6463.6

            \[\leadsto \color{blue}{x \cdot x} \]
        8. Applied rewrites63.6%

          \[\leadsto \color{blue}{x \cdot x} \]
      5. Recombined 3 regimes into one program.
      6. Final simplification66.9%

        \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -5 \cdot 10^{+266}:\\ \;\;\;\;y \cdot \left(-x\right)\\ \mathbf{elif}\;x \cdot \left(1 - x \cdot y\right) \leq 5 \cdot 10^{+222}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \]
      7. Add Preprocessing

      Alternative 4: 63.1% accurate, 0.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot \left(1 - x \cdot y\right)\\ \mathbf{if}\;t\_0 \leq -2 \cdot 10^{+302}:\\ \;\;\;\;x \cdot y\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+222}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \end{array} \]
      (FPCore (x y)
       :precision binary64
       (let* ((t_0 (* x (- 1.0 (* x y)))))
         (if (<= t_0 -2e+302) (* x y) (if (<= t_0 5e+222) (* x 1.0) (* x x)))))
      double code(double x, double y) {
      	double t_0 = x * (1.0 - (x * y));
      	double tmp;
      	if (t_0 <= -2e+302) {
      		tmp = x * y;
      	} else if (t_0 <= 5e+222) {
      		tmp = x * 1.0;
      	} else {
      		tmp = x * x;
      	}
      	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 = x * (1.0d0 - (x * y))
          if (t_0 <= (-2d+302)) then
              tmp = x * y
          else if (t_0 <= 5d+222) then
              tmp = x * 1.0d0
          else
              tmp = x * x
          end if
          code = tmp
      end function
      
      public static double code(double x, double y) {
      	double t_0 = x * (1.0 - (x * y));
      	double tmp;
      	if (t_0 <= -2e+302) {
      		tmp = x * y;
      	} else if (t_0 <= 5e+222) {
      		tmp = x * 1.0;
      	} else {
      		tmp = x * x;
      	}
      	return tmp;
      }
      
      def code(x, y):
      	t_0 = x * (1.0 - (x * y))
      	tmp = 0
      	if t_0 <= -2e+302:
      		tmp = x * y
      	elif t_0 <= 5e+222:
      		tmp = x * 1.0
      	else:
      		tmp = x * x
      	return tmp
      
      function code(x, y)
      	t_0 = Float64(x * Float64(1.0 - Float64(x * y)))
      	tmp = 0.0
      	if (t_0 <= -2e+302)
      		tmp = Float64(x * y);
      	elseif (t_0 <= 5e+222)
      		tmp = Float64(x * 1.0);
      	else
      		tmp = Float64(x * x);
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y)
      	t_0 = x * (1.0 - (x * y));
      	tmp = 0.0;
      	if (t_0 <= -2e+302)
      		tmp = x * y;
      	elseif (t_0 <= 5e+222)
      		tmp = x * 1.0;
      	else
      		tmp = x * x;
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_] := Block[{t$95$0 = N[(x * N[(1.0 - N[(x * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -2e+302], N[(x * y), $MachinePrecision], If[LessEqual[t$95$0, 5e+222], N[(x * 1.0), $MachinePrecision], N[(x * x), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_0 := x \cdot \left(1 - x \cdot y\right)\\
      \mathbf{if}\;t\_0 \leq -2 \cdot 10^{+302}:\\
      \;\;\;\;x \cdot y\\
      
      \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+222}:\\
      \;\;\;\;x \cdot 1\\
      
      \mathbf{else}:\\
      \;\;\;\;x \cdot x\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 3 regimes
      2. if (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < -2.0000000000000002e302

        1. Initial program 100.0%

          \[x \cdot \left(1 - x \cdot y\right) \]
        2. Add Preprocessing
        3. Taylor expanded in x around inf

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

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

            \[\leadsto \color{blue}{\mathsf{neg}\left(x \cdot y\right)} \]
          3. lower-*.f6425.6

            \[\leadsto -\color{blue}{x \cdot y} \]
        5. Applied rewrites25.6%

          \[\leadsto \color{blue}{-x \cdot y} \]
        6. Step-by-step derivation
          1. Applied rewrites20.9%

            \[\leadsto y \cdot \color{blue}{x} \]

          if -2.0000000000000002e302 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < 5.00000000000000023e222

          1. Initial program 99.9%

            \[x \cdot \left(1 - x \cdot y\right) \]
          2. Add Preprocessing
          3. Taylor expanded in x around 0

            \[\leadsto x \cdot \color{blue}{1} \]
          4. Step-by-step derivation
            1. Applied rewrites77.6%

              \[\leadsto x \cdot \color{blue}{1} \]

            if 5.00000000000000023e222 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y)))

            1. Initial program 100.0%

              \[x \cdot \left(1 - x \cdot y\right) \]
            2. Add Preprocessing
            3. Step-by-step derivation
              1. lift-*.f64N/A

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

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

                \[\leadsto x \cdot \color{blue}{\left(1 + \left(\mathsf{neg}\left(x \cdot y\right)\right)\right)} \]
              4. +-commutativeN/A

                \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x \cdot y\right)\right) + 1\right)} \]
              5. distribute-lft-inN/A

                \[\leadsto \color{blue}{x \cdot \left(\mathsf{neg}\left(x \cdot y\right)\right) + x \cdot 1} \]
              6. lift-*.f64N/A

                \[\leadsto x \cdot \left(\mathsf{neg}\left(\color{blue}{x \cdot y}\right)\right) + x \cdot 1 \]
              7. distribute-lft-neg-inN/A

                \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x\right)\right) \cdot y\right)} + x \cdot 1 \]
              8. associate-*r*N/A

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

                \[\leadsto \left(x \cdot \left(\mathsf{neg}\left(x\right)\right)\right) \cdot y + \color{blue}{x} \]
              10. lower-fma.f64N/A

                \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(\mathsf{neg}\left(x\right)\right), y, x\right)} \]
              11. lower-*.f64N/A

                \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot \left(\mathsf{neg}\left(x\right)\right)}, y, x\right) \]
              12. lower-neg.f6495.6

                \[\leadsto \mathsf{fma}\left(x \cdot \color{blue}{\left(-x\right)}, y, x\right) \]
            4. Applied rewrites95.6%

              \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(-x\right), y, x\right)} \]
            5. Applied rewrites0.6%

              \[\leadsto \color{blue}{\frac{x \cdot \left(x \cdot \left(x \cdot y\right)\right) - x \cdot \left(y \cdot \left(x \cdot \left(x \cdot \left(x \cdot y\right)\right)\right)\right)}{x \cdot \left(x \cdot y\right)}} \]
            6. Taylor expanded in y around inf

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

                \[\leadsto \color{blue}{x \cdot x} \]
              2. lower-*.f6463.6

                \[\leadsto \color{blue}{x \cdot x} \]
            8. Applied rewrites63.6%

              \[\leadsto \color{blue}{x \cdot x} \]
          5. Recombined 3 regimes into one program.
          6. Final simplification66.1%

            \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -2 \cdot 10^{+302}:\\ \;\;\;\;x \cdot y\\ \mathbf{elif}\;x \cdot \left(1 - x \cdot y\right) \leq 5 \cdot 10^{+222}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \]
          7. Add Preprocessing

          Alternative 5: 17.7% accurate, 0.6× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -2 \cdot 10^{-161}:\\ \;\;\;\;x \cdot y\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \end{array} \]
          (FPCore (x y)
           :precision binary64
           (if (<= (* x (- 1.0 (* x y))) -2e-161) (* x y) (* x x)))
          double code(double x, double y) {
          	double tmp;
          	if ((x * (1.0 - (x * y))) <= -2e-161) {
          		tmp = x * y;
          	} else {
          		tmp = x * x;
          	}
          	return tmp;
          }
          
          real(8) function code(x, y)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              real(8) :: tmp
              if ((x * (1.0d0 - (x * y))) <= (-2d-161)) then
                  tmp = x * y
              else
                  tmp = x * x
              end if
              code = tmp
          end function
          
          public static double code(double x, double y) {
          	double tmp;
          	if ((x * (1.0 - (x * y))) <= -2e-161) {
          		tmp = x * y;
          	} else {
          		tmp = x * x;
          	}
          	return tmp;
          }
          
          def code(x, y):
          	tmp = 0
          	if (x * (1.0 - (x * y))) <= -2e-161:
          		tmp = x * y
          	else:
          		tmp = x * x
          	return tmp
          
          function code(x, y)
          	tmp = 0.0
          	if (Float64(x * Float64(1.0 - Float64(x * y))) <= -2e-161)
          		tmp = Float64(x * y);
          	else
          		tmp = Float64(x * x);
          	end
          	return tmp
          end
          
          function tmp_2 = code(x, y)
          	tmp = 0.0;
          	if ((x * (1.0 - (x * y))) <= -2e-161)
          		tmp = x * y;
          	else
          		tmp = x * x;
          	end
          	tmp_2 = tmp;
          end
          
          code[x_, y_] := If[LessEqual[N[(x * N[(1.0 - N[(x * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -2e-161], N[(x * y), $MachinePrecision], N[(x * x), $MachinePrecision]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -2 \cdot 10^{-161}:\\
          \;\;\;\;x \cdot y\\
          
          \mathbf{else}:\\
          \;\;\;\;x \cdot x\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y))) < -2.00000000000000006e-161

            1. Initial program 99.9%

              \[x \cdot \left(1 - x \cdot y\right) \]
            2. Add Preprocessing
            3. Taylor expanded in x around inf

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

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

                \[\leadsto \color{blue}{\mathsf{neg}\left(x \cdot y\right)} \]
              3. lower-*.f6412.7

                \[\leadsto -\color{blue}{x \cdot y} \]
            5. Applied rewrites12.7%

              \[\leadsto \color{blue}{-x \cdot y} \]
            6. Step-by-step derivation
              1. Applied rewrites10.7%

                \[\leadsto y \cdot \color{blue}{x} \]

              if -2.00000000000000006e-161 < (*.f64 x (-.f64 #s(literal 1 binary64) (*.f64 x y)))

              1. Initial program 99.9%

                \[x \cdot \left(1 - x \cdot y\right) \]
              2. Add Preprocessing
              3. Step-by-step derivation
                1. lift-*.f64N/A

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

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

                  \[\leadsto x \cdot \color{blue}{\left(1 + \left(\mathsf{neg}\left(x \cdot y\right)\right)\right)} \]
                4. +-commutativeN/A

                  \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x \cdot y\right)\right) + 1\right)} \]
                5. distribute-lft-inN/A

                  \[\leadsto \color{blue}{x \cdot \left(\mathsf{neg}\left(x \cdot y\right)\right) + x \cdot 1} \]
                6. lift-*.f64N/A

                  \[\leadsto x \cdot \left(\mathsf{neg}\left(\color{blue}{x \cdot y}\right)\right) + x \cdot 1 \]
                7. distribute-lft-neg-inN/A

                  \[\leadsto x \cdot \color{blue}{\left(\left(\mathsf{neg}\left(x\right)\right) \cdot y\right)} + x \cdot 1 \]
                8. associate-*r*N/A

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

                  \[\leadsto \left(x \cdot \left(\mathsf{neg}\left(x\right)\right)\right) \cdot y + \color{blue}{x} \]
                10. lower-fma.f64N/A

                  \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(\mathsf{neg}\left(x\right)\right), y, x\right)} \]
                11. lower-*.f64N/A

                  \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot \left(\mathsf{neg}\left(x\right)\right)}, y, x\right) \]
                12. lower-neg.f6495.4

                  \[\leadsto \mathsf{fma}\left(x \cdot \color{blue}{\left(-x\right)}, y, x\right) \]
              4. Applied rewrites95.4%

                \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot \left(-x\right), y, x\right)} \]
              5. Applied rewrites27.1%

                \[\leadsto \color{blue}{\frac{x \cdot \left(x \cdot \left(x \cdot y\right)\right) - x \cdot \left(y \cdot \left(x \cdot \left(x \cdot \left(x \cdot y\right)\right)\right)\right)}{x \cdot \left(x \cdot y\right)}} \]
              6. Taylor expanded in y around inf

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

                  \[\leadsto \color{blue}{x \cdot x} \]
                2. lower-*.f6421.9

                  \[\leadsto \color{blue}{x \cdot x} \]
              8. Applied rewrites21.9%

                \[\leadsto \color{blue}{x \cdot x} \]
            7. Recombined 2 regimes into one program.
            8. Final simplification17.4%

              \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot \left(1 - x \cdot y\right) \leq -2 \cdot 10^{-161}:\\ \;\;\;\;x \cdot y\\ \mathbf{else}:\\ \;\;\;\;x \cdot x\\ \end{array} \]
            9. Add Preprocessing

            Alternative 6: 10.1% accurate, 2.3× speedup?

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

              \[x \cdot \left(1 - x \cdot y\right) \]
            2. Add Preprocessing
            3. Taylor expanded in x around inf

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

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

                \[\leadsto \color{blue}{\mathsf{neg}\left(x \cdot y\right)} \]
              3. lower-*.f6410.4

                \[\leadsto -\color{blue}{x \cdot y} \]
            5. Applied rewrites10.4%

              \[\leadsto \color{blue}{-x \cdot y} \]
            6. Step-by-step derivation
              1. Applied rewrites9.6%

                \[\leadsto y \cdot \color{blue}{x} \]
              2. Final simplification9.6%

                \[\leadsto x \cdot y \]
              3. Add Preprocessing

              Alternative 7: 4.4% accurate, 4.7× speedup?

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

                \[x \cdot \left(1 - x \cdot y\right) \]
              2. Add Preprocessing
              3. Applied rewrites69.3%

                \[\leadsto \color{blue}{\left(-x \cdot \mathsf{fma}\left(x, x \cdot \left(y \cdot y\right), 1\right)\right) \cdot \frac{1}{\mathsf{fma}\left(x, y, -1\right)}} \]
              4. Taylor expanded in x around -inf

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

                  \[\leadsto \color{blue}{\mathsf{neg}\left(y\right)} \]
                2. lower-neg.f644.0

                  \[\leadsto \color{blue}{-y} \]
              6. Applied rewrites4.0%

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

              Alternative 8: 3.1% accurate, 14.0× 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%

                \[x \cdot \left(1 - x \cdot y\right) \]
              2. Add Preprocessing
              3. Taylor expanded in x around 0

                \[\leadsto \color{blue}{1} \]
              4. Step-by-step derivation
                1. Applied rewrites3.1%

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

                Reproduce

                ?
                herbie shell --seed 2024223 
                (FPCore (x y)
                  :name "Numeric.SpecFunctions:log1p from math-functions-0.1.5.2, A"
                  :precision binary64
                  (* x (- 1.0 (* x y))))