Quotient of sum of exps

Percentage Accurate: 99.0% → 100.0%
Time: 5.5s
Alternatives: 13
Speedup: 2.7×

Specification

?
\[\begin{array}{l} \\ \frac{e^{a}}{e^{a} + e^{b}} \end{array} \]
(FPCore (a b) :precision binary64 (/ (exp a) (+ (exp a) (exp b))))
double code(double a, double b) {
	return exp(a) / (exp(a) + exp(b));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = exp(a) / (exp(a) + exp(b))
end function
public static double code(double a, double b) {
	return Math.exp(a) / (Math.exp(a) + Math.exp(b));
}
def code(a, b):
	return math.exp(a) / (math.exp(a) + math.exp(b))
function code(a, b)
	return Float64(exp(a) / Float64(exp(a) + exp(b)))
end
function tmp = code(a, b)
	tmp = exp(a) / (exp(a) + exp(b));
end
code[a_, b_] := N[(N[Exp[a], $MachinePrecision] / N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{e^{a}}{e^{a} + e^{b}}
\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 13 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: 99.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{e^{a}}{e^{a} + e^{b}} \end{array} \]
(FPCore (a b) :precision binary64 (/ (exp a) (+ (exp a) (exp b))))
double code(double a, double b) {
	return exp(a) / (exp(a) + exp(b));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = exp(a) / (exp(a) + exp(b))
end function
public static double code(double a, double b) {
	return Math.exp(a) / (Math.exp(a) + Math.exp(b));
}
def code(a, b):
	return math.exp(a) / (math.exp(a) + math.exp(b))
function code(a, b)
	return Float64(exp(a) / Float64(exp(a) + exp(b)))
end
function tmp = code(a, b)
	tmp = exp(a) / (exp(a) + exp(b));
end
code[a_, b_] := N[(N[Exp[a], $MachinePrecision] / N[(N[Exp[a], $MachinePrecision] + N[Exp[b], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{e^{a}}{e^{a} + e^{b}}
\end{array}

Alternative 1: 100.0% accurate, 2.7× speedup?

\[\begin{array}{l} \\ \frac{-1}{-1 - e^{b - a}} \end{array} \]
(FPCore (a b) :precision binary64 (/ -1.0 (- -1.0 (exp (- b a)))))
double code(double a, double b) {
	return -1.0 / (-1.0 - exp((b - a)));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (-1.0d0) / ((-1.0d0) - exp((b - a)))
end function
public static double code(double a, double b) {
	return -1.0 / (-1.0 - Math.exp((b - a)));
}
def code(a, b):
	return -1.0 / (-1.0 - math.exp((b - a)))
function code(a, b)
	return Float64(-1.0 / Float64(-1.0 - exp(Float64(b - a))))
end
function tmp = code(a, b)
	tmp = -1.0 / (-1.0 - exp((b - a)));
end
code[a_, b_] := N[(-1.0 / N[(-1.0 - N[Exp[N[(b - a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-1}{-1 - e^{b - a}}
\end{array}
Derivation
  1. Initial program 99.2%

    \[\frac{e^{a}}{e^{a} + e^{b}} \]
  2. Add Preprocessing
  3. Taylor expanded in b around 0

    \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
  4. Step-by-step derivation
    1. Applied rewrites65.0%

      \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
    2. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{e^{a}}{e^{a} + 1}} \]
      2. div-invN/A

        \[\leadsto \color{blue}{e^{a} \cdot \frac{1}{e^{a} + 1}} \]
      3. remove-double-divN/A

        \[\leadsto \color{blue}{\frac{1}{\frac{1}{e^{a}}}} \cdot \frac{1}{e^{a} + 1} \]
      4. lift-exp.f64N/A

        \[\leadsto \frac{1}{\frac{1}{\color{blue}{e^{a}}}} \cdot \frac{1}{e^{a} + 1} \]
      5. exp-negN/A

        \[\leadsto \frac{1}{\color{blue}{e^{\mathsf{neg}\left(a\right)}}} \cdot \frac{1}{e^{a} + 1} \]
      6. lift-neg.f64N/A

        \[\leadsto \frac{1}{e^{\color{blue}{-a}}} \cdot \frac{1}{e^{a} + 1} \]
      7. lift-exp.f64N/A

        \[\leadsto \frac{1}{\color{blue}{e^{-a}}} \cdot \frac{1}{e^{a} + 1} \]
      8. frac-2negN/A

        \[\leadsto \frac{1}{e^{-a}} \cdot \color{blue}{\frac{\mathsf{neg}\left(1\right)}{\mathsf{neg}\left(\left(e^{a} + 1\right)\right)}} \]
      9. metadata-evalN/A

        \[\leadsto \frac{1}{e^{-a}} \cdot \frac{\color{blue}{-1}}{\mathsf{neg}\left(\left(e^{a} + 1\right)\right)} \]
      10. frac-timesN/A

        \[\leadsto \color{blue}{\frac{1 \cdot -1}{e^{-a} \cdot \left(\mathsf{neg}\left(\left(e^{a} + 1\right)\right)\right)}} \]
      11. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{-1}}{e^{-a} \cdot \left(\mathsf{neg}\left(\left(e^{a} + 1\right)\right)\right)} \]
      12. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{e^{-a} \cdot \left(\mathsf{neg}\left(\left(e^{a} + 1\right)\right)\right)}} \]
      13. lower-*.f64N/A

        \[\leadsto \frac{-1}{\color{blue}{e^{-a} \cdot \left(\mathsf{neg}\left(\left(e^{a} + 1\right)\right)\right)}} \]
      14. lower-neg.f6465.0

        \[\leadsto \frac{-1}{e^{-a} \cdot \color{blue}{\left(-\left(e^{a} + 1\right)\right)}} \]
      15. lift-+.f64N/A

        \[\leadsto \frac{-1}{e^{-a} \cdot \left(-\color{blue}{\left(e^{a} + 1\right)}\right)} \]
      16. +-commutativeN/A

        \[\leadsto \frac{-1}{e^{-a} \cdot \left(-\color{blue}{\left(1 + e^{a}\right)}\right)} \]
      17. lower-+.f6465.0

        \[\leadsto \frac{-1}{e^{-a} \cdot \left(-\color{blue}{\left(1 + e^{a}\right)}\right)} \]
    3. Applied rewrites65.0%

      \[\leadsto \color{blue}{\frac{-1}{e^{-a} \cdot \left(-\left(1 + e^{a}\right)\right)}} \]
    4. Taylor expanded in b around inf

      \[\leadsto \frac{-1}{\color{blue}{-1 \cdot \left(e^{\mathsf{neg}\left(a\right)} \cdot \left(e^{a} + e^{b}\right)\right)}} \]
    5. Step-by-step derivation
      1. associate-*r*N/A

        \[\leadsto \frac{-1}{\color{blue}{\left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot \left(e^{a} + e^{b}\right)}} \]
      2. distribute-lft-inN/A

        \[\leadsto \frac{-1}{\color{blue}{\left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{a} + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{-1}{\color{blue}{\left(\mathsf{neg}\left(e^{\mathsf{neg}\left(a\right)}\right)\right)} \cdot e^{a} + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}} \]
      4. distribute-lft-neg-outN/A

        \[\leadsto \frac{-1}{\color{blue}{\left(\mathsf{neg}\left(e^{\mathsf{neg}\left(a\right)} \cdot e^{a}\right)\right)} + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}} \]
      5. exp-negN/A

        \[\leadsto \frac{-1}{\left(\mathsf{neg}\left(\color{blue}{\frac{1}{e^{a}}} \cdot e^{a}\right)\right) + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}} \]
      6. lft-mult-inverseN/A

        \[\leadsto \frac{-1}{\left(\mathsf{neg}\left(\color{blue}{1}\right)\right) + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}} \]
      7. metadata-evalN/A

        \[\leadsto \frac{-1}{\color{blue}{-1} + \left(-1 \cdot e^{\mathsf{neg}\left(a\right)}\right) \cdot e^{b}} \]
      8. mul-1-negN/A

        \[\leadsto \frac{-1}{-1 + \color{blue}{\left(\mathsf{neg}\left(e^{\mathsf{neg}\left(a\right)}\right)\right)} \cdot e^{b}} \]
      9. distribute-lft-neg-inN/A

        \[\leadsto \frac{-1}{-1 + \color{blue}{\left(\mathsf{neg}\left(e^{\mathsf{neg}\left(a\right)} \cdot e^{b}\right)\right)}} \]
      10. unsub-negN/A

        \[\leadsto \frac{-1}{\color{blue}{-1 - e^{\mathsf{neg}\left(a\right)} \cdot e^{b}}} \]
      11. lower--.f64N/A

        \[\leadsto \frac{-1}{\color{blue}{-1 - e^{\mathsf{neg}\left(a\right)} \cdot e^{b}}} \]
      12. *-commutativeN/A

        \[\leadsto \frac{-1}{-1 - \color{blue}{e^{b} \cdot e^{\mathsf{neg}\left(a\right)}}} \]
      13. neg-mul-1N/A

        \[\leadsto \frac{-1}{-1 - e^{b} \cdot e^{\color{blue}{-1 \cdot a}}} \]
      14. prod-expN/A

        \[\leadsto \frac{-1}{-1 - \color{blue}{e^{b + -1 \cdot a}}} \]
      15. lower-exp.f64N/A

        \[\leadsto \frac{-1}{-1 - \color{blue}{e^{b + -1 \cdot a}}} \]
      16. neg-mul-1N/A

        \[\leadsto \frac{-1}{-1 - e^{b + \color{blue}{\left(\mathsf{neg}\left(a\right)\right)}}} \]
      17. unsub-negN/A

        \[\leadsto \frac{-1}{-1 - e^{\color{blue}{b - a}}} \]
      18. lower--.f64100.0

        \[\leadsto \frac{-1}{-1 - e^{\color{blue}{b - a}}} \]
    6. Applied rewrites100.0%

      \[\leadsto \frac{-1}{\color{blue}{-1 - e^{b - a}}} \]
    7. Add Preprocessing

    Alternative 2: 98.2% accurate, 2.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -55000000000000:\\ \;\;\;\;\frac{e^{a}}{1 + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{e^{b} + 1}\\ \end{array} \end{array} \]
    (FPCore (a b)
     :precision binary64
     (if (<= a -55000000000000.0) (/ (exp a) (+ 1.0 1.0)) (/ 1.0 (+ (exp b) 1.0))))
    double code(double a, double b) {
    	double tmp;
    	if (a <= -55000000000000.0) {
    		tmp = exp(a) / (1.0 + 1.0);
    	} else {
    		tmp = 1.0 / (exp(b) + 1.0);
    	}
    	return tmp;
    }
    
    real(8) function code(a, b)
        real(8), intent (in) :: a
        real(8), intent (in) :: b
        real(8) :: tmp
        if (a <= (-55000000000000.0d0)) then
            tmp = exp(a) / (1.0d0 + 1.0d0)
        else
            tmp = 1.0d0 / (exp(b) + 1.0d0)
        end if
        code = tmp
    end function
    
    public static double code(double a, double b) {
    	double tmp;
    	if (a <= -55000000000000.0) {
    		tmp = Math.exp(a) / (1.0 + 1.0);
    	} else {
    		tmp = 1.0 / (Math.exp(b) + 1.0);
    	}
    	return tmp;
    }
    
    def code(a, b):
    	tmp = 0
    	if a <= -55000000000000.0:
    		tmp = math.exp(a) / (1.0 + 1.0)
    	else:
    		tmp = 1.0 / (math.exp(b) + 1.0)
    	return tmp
    
    function code(a, b)
    	tmp = 0.0
    	if (a <= -55000000000000.0)
    		tmp = Float64(exp(a) / Float64(1.0 + 1.0));
    	else
    		tmp = Float64(1.0 / Float64(exp(b) + 1.0));
    	end
    	return tmp
    end
    
    function tmp_2 = code(a, b)
    	tmp = 0.0;
    	if (a <= -55000000000000.0)
    		tmp = exp(a) / (1.0 + 1.0);
    	else
    		tmp = 1.0 / (exp(b) + 1.0);
    	end
    	tmp_2 = tmp;
    end
    
    code[a_, b_] := If[LessEqual[a, -55000000000000.0], N[(N[Exp[a], $MachinePrecision] / N[(1.0 + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Exp[b], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;a \leq -55000000000000:\\
    \;\;\;\;\frac{e^{a}}{1 + 1}\\
    
    \mathbf{else}:\\
    \;\;\;\;\frac{1}{e^{b} + 1}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if a < -5.5e13

      1. Initial program 100.0%

        \[\frac{e^{a}}{e^{a} + e^{b}} \]
      2. Add Preprocessing
      3. Taylor expanded in b around 0

        \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
      4. Step-by-step derivation
        1. Applied rewrites100.0%

          \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
        2. Taylor expanded in a around 0

          \[\leadsto \frac{e^{a}}{\color{blue}{1} + 1} \]
        3. Step-by-step derivation
          1. Applied rewrites100.0%

            \[\leadsto \frac{e^{a}}{\color{blue}{1} + 1} \]

          if -5.5e13 < a

          1. Initial program 98.9%

            \[\frac{e^{a}}{e^{a} + e^{b}} \]
          2. Add Preprocessing
          3. Taylor expanded in a around 0

            \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
          4. Step-by-step derivation
            1. lower-/.f64N/A

              \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
            2. +-commutativeN/A

              \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
            3. lower-+.f64N/A

              \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
            4. lower-exp.f6498.2

              \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
          5. Applied rewrites98.2%

            \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
        4. Recombined 2 regimes into one program.
        5. Final simplification98.7%

          \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -55000000000000:\\ \;\;\;\;\frac{e^{a}}{1 + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{e^{b} + 1}\\ \end{array} \]
        6. Add Preprocessing

        Alternative 3: 93.0% accurate, 2.6× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -1 \cdot 10^{+103}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{e^{b} + 1}\\ \end{array} \end{array} \]
        (FPCore (a b)
         :precision binary64
         (if (<= a -1e+103)
           (/ 1.0 (+ (fma (fma (fma 0.16666666666666666 a 0.5) a 1.0) a 1.0) 1.0))
           (/ 1.0 (+ (exp b) 1.0))))
        double code(double a, double b) {
        	double tmp;
        	if (a <= -1e+103) {
        		tmp = 1.0 / (fma(fma(fma(0.16666666666666666, a, 0.5), a, 1.0), a, 1.0) + 1.0);
        	} else {
        		tmp = 1.0 / (exp(b) + 1.0);
        	}
        	return tmp;
        }
        
        function code(a, b)
        	tmp = 0.0
        	if (a <= -1e+103)
        		tmp = Float64(1.0 / Float64(fma(fma(fma(0.16666666666666666, a, 0.5), a, 1.0), a, 1.0) + 1.0));
        	else
        		tmp = Float64(1.0 / Float64(exp(b) + 1.0));
        	end
        	return tmp
        end
        
        code[a_, b_] := If[LessEqual[a, -1e+103], N[(1.0 / N[(N[(N[(N[(0.16666666666666666 * a + 0.5), $MachinePrecision] * a + 1.0), $MachinePrecision] * a + 1.0), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Exp[b], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        \mathbf{if}\;a \leq -1 \cdot 10^{+103}:\\
        \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1}\\
        
        \mathbf{else}:\\
        \;\;\;\;\frac{1}{e^{b} + 1}\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if a < -1e103

          1. Initial program 100.0%

            \[\frac{e^{a}}{e^{a} + e^{b}} \]
          2. Add Preprocessing
          3. Taylor expanded in b around 0

            \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
          4. Step-by-step derivation
            1. Applied rewrites100.0%

              \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
            2. Taylor expanded in a around 0

              \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a \cdot \left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right)\right)} + 1} \]
            3. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \frac{e^{a}}{\color{blue}{\left(a \cdot \left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right) + 1\right)} + 1} \]
              2. *-commutativeN/A

                \[\leadsto \frac{e^{a}}{\left(\color{blue}{\left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right) \cdot a} + 1\right) + 1} \]
              3. lower-fma.f64N/A

                \[\leadsto \frac{e^{a}}{\color{blue}{\mathsf{fma}\left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right), a, 1\right)} + 1} \]
              4. +-commutativeN/A

                \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right) + 1}, a, 1\right) + 1} \]
              5. *-commutativeN/A

                \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{\left(\frac{1}{2} + \frac{1}{6} \cdot a\right) \cdot a} + 1, a, 1\right) + 1} \]
              6. lower-fma.f64N/A

                \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{6} \cdot a, a, 1\right)}, a, 1\right) + 1} \]
              7. +-commutativeN/A

                \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\frac{1}{6} \cdot a + \frac{1}{2}}, a, 1\right), a, 1\right) + 1} \]
              8. lower-fma.f64100.0

                \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(0.16666666666666666, a, 0.5\right)}, a, 1\right), a, 1\right) + 1} \]
            4. Applied rewrites100.0%

              \[\leadsto \frac{e^{a}}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right)} + 1} \]
            5. Taylor expanded in a around 0

              \[\leadsto \frac{\color{blue}{1}}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{6}, a, \frac{1}{2}\right), a, 1\right), a, 1\right) + 1} \]
            6. Step-by-step derivation
              1. Applied rewrites100.0%

                \[\leadsto \frac{\color{blue}{1}}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1} \]

              if -1e103 < a

              1. Initial program 99.0%

                \[\frac{e^{a}}{e^{a} + e^{b}} \]
              2. Add Preprocessing
              3. Taylor expanded in a around 0

                \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
              4. Step-by-step derivation
                1. lower-/.f64N/A

                  \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                2. +-commutativeN/A

                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                3. lower-+.f64N/A

                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                4. lower-exp.f6494.9

                  \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
              5. Applied rewrites94.9%

                \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
            7. Recombined 2 regimes into one program.
            8. Add Preprocessing

            Alternative 4: 70.2% accurate, 8.1× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 3 \cdot 10^{+79}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\ \end{array} \end{array} \]
            (FPCore (a b)
             :precision binary64
             (if (<= b 3e+79)
               (/ 1.0 (+ (fma (fma (fma 0.16666666666666666 a 0.5) a 1.0) a 1.0) 1.0))
               (/ 1.0 (* (* (fma 0.16666666666666666 b 0.5) b) b))))
            double code(double a, double b) {
            	double tmp;
            	if (b <= 3e+79) {
            		tmp = 1.0 / (fma(fma(fma(0.16666666666666666, a, 0.5), a, 1.0), a, 1.0) + 1.0);
            	} else {
            		tmp = 1.0 / ((fma(0.16666666666666666, b, 0.5) * b) * b);
            	}
            	return tmp;
            }
            
            function code(a, b)
            	tmp = 0.0
            	if (b <= 3e+79)
            		tmp = Float64(1.0 / Float64(fma(fma(fma(0.16666666666666666, a, 0.5), a, 1.0), a, 1.0) + 1.0));
            	else
            		tmp = Float64(1.0 / Float64(Float64(fma(0.16666666666666666, b, 0.5) * b) * b));
            	end
            	return tmp
            end
            
            code[a_, b_] := If[LessEqual[b, 3e+79], N[(1.0 / N[(N[(N[(N[(0.16666666666666666 * a + 0.5), $MachinePrecision] * a + 1.0), $MachinePrecision] * a + 1.0), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[(0.16666666666666666 * b + 0.5), $MachinePrecision] * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision]]
            
            \begin{array}{l}
            
            \\
            \begin{array}{l}
            \mathbf{if}\;b \leq 3 \cdot 10^{+79}:\\
            \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1}\\
            
            \mathbf{else}:\\
            \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\
            
            
            \end{array}
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if b < 2.99999999999999974e79

              1. Initial program 99.0%

                \[\frac{e^{a}}{e^{a} + e^{b}} \]
              2. Add Preprocessing
              3. Taylor expanded in b around 0

                \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
              4. Step-by-step derivation
                1. Applied rewrites71.0%

                  \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                2. Taylor expanded in a around 0

                  \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a \cdot \left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right)\right)} + 1} \]
                3. Step-by-step derivation
                  1. +-commutativeN/A

                    \[\leadsto \frac{e^{a}}{\color{blue}{\left(a \cdot \left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right) + 1\right)} + 1} \]
                  2. *-commutativeN/A

                    \[\leadsto \frac{e^{a}}{\left(\color{blue}{\left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right)\right) \cdot a} + 1\right) + 1} \]
                  3. lower-fma.f64N/A

                    \[\leadsto \frac{e^{a}}{\color{blue}{\mathsf{fma}\left(1 + a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right), a, 1\right)} + 1} \]
                  4. +-commutativeN/A

                    \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{a \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot a\right) + 1}, a, 1\right) + 1} \]
                  5. *-commutativeN/A

                    \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{\left(\frac{1}{2} + \frac{1}{6} \cdot a\right) \cdot a} + 1, a, 1\right) + 1} \]
                  6. lower-fma.f64N/A

                    \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{6} \cdot a, a, 1\right)}, a, 1\right) + 1} \]
                  7. +-commutativeN/A

                    \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\frac{1}{6} \cdot a + \frac{1}{2}}, a, 1\right), a, 1\right) + 1} \]
                  8. lower-fma.f6470.7

                    \[\leadsto \frac{e^{a}}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(0.16666666666666666, a, 0.5\right)}, a, 1\right), a, 1\right) + 1} \]
                4. Applied rewrites70.7%

                  \[\leadsto \frac{e^{a}}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right)} + 1} \]
                5. Taylor expanded in a around 0

                  \[\leadsto \frac{\color{blue}{1}}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{6}, a, \frac{1}{2}\right), a, 1\right), a, 1\right) + 1} \]
                6. Step-by-step derivation
                  1. Applied rewrites66.0%

                    \[\leadsto \frac{\color{blue}{1}}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, a, 0.5\right), a, 1\right), a, 1\right) + 1} \]

                  if 2.99999999999999974e79 < b

                  1. Initial program 100.0%

                    \[\frac{e^{a}}{e^{a} + e^{b}} \]
                  2. Add Preprocessing
                  3. Taylor expanded in a around 0

                    \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                  4. Step-by-step derivation
                    1. lower-/.f64N/A

                      \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                    2. +-commutativeN/A

                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                    3. lower-+.f64N/A

                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                    4. lower-exp.f64100.0

                      \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                  5. Applied rewrites100.0%

                    \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                  6. Taylor expanded in b around 0

                    \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + b \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot b\right)\right)}} \]
                  7. Step-by-step derivation
                    1. Applied rewrites90.9%

                      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), \color{blue}{b}, 2\right)} \]
                    2. Taylor expanded in b around inf

                      \[\leadsto \frac{1}{{b}^{3} \cdot \left(\frac{1}{6} + \color{blue}{\frac{1}{2} \cdot \frac{1}{b}}\right)} \]
                    3. Step-by-step derivation
                      1. Applied rewrites90.9%

                        \[\leadsto \frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b} \]
                    4. Recombined 2 regimes into one program.
                    5. Add Preprocessing

                    Alternative 5: 66.9% accurate, 8.7× speedup?

                    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 3 \cdot 10^{+79}:\\ \;\;\;\;\frac{1 + a}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, a, 1\right), a, 1\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\ \end{array} \end{array} \]
                    (FPCore (a b)
                     :precision binary64
                     (if (<= b 3e+79)
                       (/ (+ 1.0 a) (+ (fma (fma 0.5 a 1.0) a 1.0) 1.0))
                       (/ 1.0 (* (* (fma 0.16666666666666666 b 0.5) b) b))))
                    double code(double a, double b) {
                    	double tmp;
                    	if (b <= 3e+79) {
                    		tmp = (1.0 + a) / (fma(fma(0.5, a, 1.0), a, 1.0) + 1.0);
                    	} else {
                    		tmp = 1.0 / ((fma(0.16666666666666666, b, 0.5) * b) * b);
                    	}
                    	return tmp;
                    }
                    
                    function code(a, b)
                    	tmp = 0.0
                    	if (b <= 3e+79)
                    		tmp = Float64(Float64(1.0 + a) / Float64(fma(fma(0.5, a, 1.0), a, 1.0) + 1.0));
                    	else
                    		tmp = Float64(1.0 / Float64(Float64(fma(0.16666666666666666, b, 0.5) * b) * b));
                    	end
                    	return tmp
                    end
                    
                    code[a_, b_] := If[LessEqual[b, 3e+79], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(N[(0.5 * a + 1.0), $MachinePrecision] * a + 1.0), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[(0.16666666666666666 * b + 0.5), $MachinePrecision] * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision]]
                    
                    \begin{array}{l}
                    
                    \\
                    \begin{array}{l}
                    \mathbf{if}\;b \leq 3 \cdot 10^{+79}:\\
                    \;\;\;\;\frac{1 + a}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, a, 1\right), a, 1\right) + 1}\\
                    
                    \mathbf{else}:\\
                    \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\
                    
                    
                    \end{array}
                    \end{array}
                    
                    Derivation
                    1. Split input into 2 regimes
                    2. if b < 2.99999999999999974e79

                      1. Initial program 99.0%

                        \[\frac{e^{a}}{e^{a} + e^{b}} \]
                      2. Add Preprocessing
                      3. Taylor expanded in b around 0

                        \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                      4. Step-by-step derivation
                        1. Applied rewrites71.0%

                          \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                        2. Taylor expanded in a around 0

                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                        3. Step-by-step derivation
                          1. lower-+.f6470.3

                            \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                        4. Applied rewrites70.3%

                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                        5. Taylor expanded in a around 0

                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                        6. Step-by-step derivation
                          1. lower-+.f6447.4

                            \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                        7. Applied rewrites47.4%

                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                        8. Taylor expanded in a around 0

                          \[\leadsto \frac{1 + a}{\color{blue}{\left(1 + a \cdot \left(1 + \frac{1}{2} \cdot a\right)\right)} + 1} \]
                        9. Step-by-step derivation
                          1. +-commutativeN/A

                            \[\leadsto \frac{1 + a}{\color{blue}{\left(a \cdot \left(1 + \frac{1}{2} \cdot a\right) + 1\right)} + 1} \]
                          2. *-commutativeN/A

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

                            \[\leadsto \frac{1 + a}{\color{blue}{\mathsf{fma}\left(1 + \frac{1}{2} \cdot a, a, 1\right)} + 1} \]
                          4. +-commutativeN/A

                            \[\leadsto \frac{1 + a}{\mathsf{fma}\left(\color{blue}{\frac{1}{2} \cdot a + 1}, a, 1\right) + 1} \]
                          5. lower-fma.f6460.0

                            \[\leadsto \frac{1 + a}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(0.5, a, 1\right)}, a, 1\right) + 1} \]
                        10. Applied rewrites60.0%

                          \[\leadsto \frac{1 + a}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, a, 1\right), a, 1\right)} + 1} \]

                        if 2.99999999999999974e79 < b

                        1. Initial program 100.0%

                          \[\frac{e^{a}}{e^{a} + e^{b}} \]
                        2. Add Preprocessing
                        3. Taylor expanded in a around 0

                          \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                        4. Step-by-step derivation
                          1. lower-/.f64N/A

                            \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                          2. +-commutativeN/A

                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                          3. lower-+.f64N/A

                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                          4. lower-exp.f64100.0

                            \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                        5. Applied rewrites100.0%

                          \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                        6. Taylor expanded in b around 0

                          \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + b \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot b\right)\right)}} \]
                        7. Step-by-step derivation
                          1. Applied rewrites90.9%

                            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), \color{blue}{b}, 2\right)} \]
                          2. Taylor expanded in b around inf

                            \[\leadsto \frac{1}{{b}^{3} \cdot \left(\frac{1}{6} + \color{blue}{\frac{1}{2} \cdot \frac{1}{b}}\right)} \]
                          3. Step-by-step derivation
                            1. Applied rewrites90.9%

                              \[\leadsto \frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b} \]
                          4. Recombined 2 regimes into one program.
                          5. Add Preprocessing

                          Alternative 6: 58.3% accurate, 8.7× speedup?

                          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 8.8 \cdot 10^{-13}:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), b, 2\right)}\\ \end{array} \end{array} \]
                          (FPCore (a b)
                           :precision binary64
                           (if (<= b 8.8e-13)
                             (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0))
                             (/ 1.0 (fma (fma (fma 0.16666666666666666 b 0.5) b 1.0) b 2.0))))
                          double code(double a, double b) {
                          	double tmp;
                          	if (b <= 8.8e-13) {
                          		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                          	} else {
                          		tmp = 1.0 / fma(fma(fma(0.16666666666666666, b, 0.5), b, 1.0), b, 2.0);
                          	}
                          	return tmp;
                          }
                          
                          function code(a, b)
                          	tmp = 0.0
                          	if (b <= 8.8e-13)
                          		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                          	else
                          		tmp = Float64(1.0 / fma(fma(fma(0.16666666666666666, b, 0.5), b, 1.0), b, 2.0));
                          	end
                          	return tmp
                          end
                          
                          code[a_, b_] := If[LessEqual[b, 8.8e-13], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[(0.16666666666666666 * b + 0.5), $MachinePrecision] * b + 1.0), $MachinePrecision] * b + 2.0), $MachinePrecision]), $MachinePrecision]]
                          
                          \begin{array}{l}
                          
                          \\
                          \begin{array}{l}
                          \mathbf{if}\;b \leq 8.8 \cdot 10^{-13}:\\
                          \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                          
                          \mathbf{else}:\\
                          \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), b, 2\right)}\\
                          
                          
                          \end{array}
                          \end{array}
                          
                          Derivation
                          1. Split input into 2 regimes
                          2. if b < 8.79999999999999986e-13

                            1. Initial program 98.9%

                              \[\frac{e^{a}}{e^{a} + e^{b}} \]
                            2. Add Preprocessing
                            3. Taylor expanded in b around 0

                              \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                            4. Step-by-step derivation
                              1. Applied rewrites74.1%

                                \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                              2. Taylor expanded in a around 0

                                \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                              3. Step-by-step derivation
                                1. lower-+.f6473.4

                                  \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                              4. Applied rewrites73.4%

                                \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                              5. Taylor expanded in a around 0

                                \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                              6. Step-by-step derivation
                                1. lower-+.f6451.4

                                  \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                              7. Applied rewrites51.4%

                                \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                              if 8.79999999999999986e-13 < b

                              1. Initial program 100.0%

                                \[\frac{e^{a}}{e^{a} + e^{b}} \]
                              2. Add Preprocessing
                              3. Taylor expanded in a around 0

                                \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                              4. Step-by-step derivation
                                1. lower-/.f64N/A

                                  \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                2. +-commutativeN/A

                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                3. lower-+.f64N/A

                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                4. lower-exp.f64100.0

                                  \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                              5. Applied rewrites100.0%

                                \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                              6. Taylor expanded in b around 0

                                \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + b \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot b\right)\right)}} \]
                              7. Step-by-step derivation
                                1. Applied rewrites73.1%

                                  \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), \color{blue}{b}, 2\right)} \]
                              8. Recombined 2 regimes into one program.
                              9. Add Preprocessing

                              Alternative 7: 58.1% accurate, 9.0× speedup?

                              \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 1.15:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b, b, b\right)}\\ \end{array} \end{array} \]
                              (FPCore (a b)
                               :precision binary64
                               (if (<= b 1.15)
                                 (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0))
                                 (/ 1.0 (fma (* (fma 0.16666666666666666 b 0.5) b) b b))))
                              double code(double a, double b) {
                              	double tmp;
                              	if (b <= 1.15) {
                              		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                              	} else {
                              		tmp = 1.0 / fma((fma(0.16666666666666666, b, 0.5) * b), b, b);
                              	}
                              	return tmp;
                              }
                              
                              function code(a, b)
                              	tmp = 0.0
                              	if (b <= 1.15)
                              		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                              	else
                              		tmp = Float64(1.0 / fma(Float64(fma(0.16666666666666666, b, 0.5) * b), b, b));
                              	end
                              	return tmp
                              end
                              
                              code[a_, b_] := If[LessEqual[b, 1.15], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[(0.16666666666666666 * b + 0.5), $MachinePrecision] * b), $MachinePrecision] * b + b), $MachinePrecision]), $MachinePrecision]]
                              
                              \begin{array}{l}
                              
                              \\
                              \begin{array}{l}
                              \mathbf{if}\;b \leq 1.15:\\
                              \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                              
                              \mathbf{else}:\\
                              \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b, b, b\right)}\\
                              
                              
                              \end{array}
                              \end{array}
                              
                              Derivation
                              1. Split input into 2 regimes
                              2. if b < 1.1499999999999999

                                1. Initial program 98.9%

                                  \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                2. Add Preprocessing
                                3. Taylor expanded in b around 0

                                  \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                4. Step-by-step derivation
                                  1. Applied rewrites73.8%

                                    \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                  2. Taylor expanded in a around 0

                                    \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                  3. Step-by-step derivation
                                    1. lower-+.f6473.1

                                      \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                  4. Applied rewrites73.1%

                                    \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                  5. Taylor expanded in a around 0

                                    \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                  6. Step-by-step derivation
                                    1. lower-+.f6451.4

                                      \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                  7. Applied rewrites51.4%

                                    \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                                  if 1.1499999999999999 < b

                                  1. Initial program 100.0%

                                    \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                  2. Add Preprocessing
                                  3. Taylor expanded in a around 0

                                    \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                  4. Step-by-step derivation
                                    1. lower-/.f64N/A

                                      \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                    2. +-commutativeN/A

                                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                    3. lower-+.f64N/A

                                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                    4. lower-exp.f64100.0

                                      \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                  5. Applied rewrites100.0%

                                    \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                  6. Taylor expanded in b around 0

                                    \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + b \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot b\right)\right)}} \]
                                  7. Step-by-step derivation
                                    1. Applied rewrites73.0%

                                      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), \color{blue}{b}, 2\right)} \]
                                    2. Taylor expanded in b around inf

                                      \[\leadsto \frac{1}{{b}^{3} \cdot \left(\frac{1}{6} + \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{b} + \frac{1}{{b}^{2}}\right)}\right)} \]
                                    3. Step-by-step derivation
                                      1. Applied rewrites73.0%

                                        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b, b, b\right)} \]
                                    4. Recombined 2 regimes into one program.
                                    5. Add Preprocessing

                                    Alternative 8: 58.1% accurate, 9.3× speedup?

                                    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 1.65:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\ \end{array} \end{array} \]
                                    (FPCore (a b)
                                     :precision binary64
                                     (if (<= b 1.65)
                                       (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0))
                                       (/ 1.0 (* (* (fma 0.16666666666666666 b 0.5) b) b))))
                                    double code(double a, double b) {
                                    	double tmp;
                                    	if (b <= 1.65) {
                                    		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                    	} else {
                                    		tmp = 1.0 / ((fma(0.16666666666666666, b, 0.5) * b) * b);
                                    	}
                                    	return tmp;
                                    }
                                    
                                    function code(a, b)
                                    	tmp = 0.0
                                    	if (b <= 1.65)
                                    		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                                    	else
                                    		tmp = Float64(1.0 / Float64(Float64(fma(0.16666666666666666, b, 0.5) * b) * b));
                                    	end
                                    	return tmp
                                    end
                                    
                                    code[a_, b_] := If[LessEqual[b, 1.65], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[(0.16666666666666666 * b + 0.5), $MachinePrecision] * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision]]
                                    
                                    \begin{array}{l}
                                    
                                    \\
                                    \begin{array}{l}
                                    \mathbf{if}\;b \leq 1.65:\\
                                    \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                                    
                                    \mathbf{else}:\\
                                    \;\;\;\;\frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b}\\
                                    
                                    
                                    \end{array}
                                    \end{array}
                                    
                                    Derivation
                                    1. Split input into 2 regimes
                                    2. if b < 1.6499999999999999

                                      1. Initial program 98.9%

                                        \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                      2. Add Preprocessing
                                      3. Taylor expanded in b around 0

                                        \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                      4. Step-by-step derivation
                                        1. Applied rewrites73.8%

                                          \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                        2. Taylor expanded in a around 0

                                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                        3. Step-by-step derivation
                                          1. lower-+.f6473.1

                                            \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                        4. Applied rewrites73.1%

                                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                        5. Taylor expanded in a around 0

                                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                        6. Step-by-step derivation
                                          1. lower-+.f6451.4

                                            \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                        7. Applied rewrites51.4%

                                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                                        if 1.6499999999999999 < b

                                        1. Initial program 100.0%

                                          \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                        2. Add Preprocessing
                                        3. Taylor expanded in a around 0

                                          \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                        4. Step-by-step derivation
                                          1. lower-/.f64N/A

                                            \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                          2. +-commutativeN/A

                                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                          3. lower-+.f64N/A

                                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                          4. lower-exp.f64100.0

                                            \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                        5. Applied rewrites100.0%

                                          \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                        6. Taylor expanded in b around 0

                                          \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + b \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot b\right)\right)}} \]
                                        7. Step-by-step derivation
                                          1. Applied rewrites73.0%

                                            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right), b, 1\right), \color{blue}{b}, 2\right)} \]
                                          2. Taylor expanded in b around inf

                                            \[\leadsto \frac{1}{{b}^{3} \cdot \left(\frac{1}{6} + \color{blue}{\frac{1}{2} \cdot \frac{1}{b}}\right)} \]
                                          3. Step-by-step derivation
                                            1. Applied rewrites73.0%

                                              \[\leadsto \frac{1}{\left(\mathsf{fma}\left(0.16666666666666666, b, 0.5\right) \cdot b\right) \cdot b} \]
                                          4. Recombined 2 regimes into one program.
                                          5. Add Preprocessing

                                          Alternative 9: 53.4% accurate, 10.5× speedup?

                                          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 8.8 \cdot 10^{-13}:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, b, 1\right), b, 2\right)}\\ \end{array} \end{array} \]
                                          (FPCore (a b)
                                           :precision binary64
                                           (if (<= b 8.8e-13)
                                             (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0))
                                             (/ 1.0 (fma (fma 0.5 b 1.0) b 2.0))))
                                          double code(double a, double b) {
                                          	double tmp;
                                          	if (b <= 8.8e-13) {
                                          		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                          	} else {
                                          		tmp = 1.0 / fma(fma(0.5, b, 1.0), b, 2.0);
                                          	}
                                          	return tmp;
                                          }
                                          
                                          function code(a, b)
                                          	tmp = 0.0
                                          	if (b <= 8.8e-13)
                                          		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                                          	else
                                          		tmp = Float64(1.0 / fma(fma(0.5, b, 1.0), b, 2.0));
                                          	end
                                          	return tmp
                                          end
                                          
                                          code[a_, b_] := If[LessEqual[b, 8.8e-13], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(0.5 * b + 1.0), $MachinePrecision] * b + 2.0), $MachinePrecision]), $MachinePrecision]]
                                          
                                          \begin{array}{l}
                                          
                                          \\
                                          \begin{array}{l}
                                          \mathbf{if}\;b \leq 8.8 \cdot 10^{-13}:\\
                                          \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                                          
                                          \mathbf{else}:\\
                                          \;\;\;\;\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, b, 1\right), b, 2\right)}\\
                                          
                                          
                                          \end{array}
                                          \end{array}
                                          
                                          Derivation
                                          1. Split input into 2 regimes
                                          2. if b < 8.79999999999999986e-13

                                            1. Initial program 98.9%

                                              \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                            2. Add Preprocessing
                                            3. Taylor expanded in b around 0

                                              \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                            4. Step-by-step derivation
                                              1. Applied rewrites74.1%

                                                \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                              2. Taylor expanded in a around 0

                                                \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                              3. Step-by-step derivation
                                                1. lower-+.f6473.4

                                                  \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                              4. Applied rewrites73.4%

                                                \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                              5. Taylor expanded in a around 0

                                                \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                              6. Step-by-step derivation
                                                1. lower-+.f6451.4

                                                  \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                              7. Applied rewrites51.4%

                                                \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                                              if 8.79999999999999986e-13 < b

                                              1. Initial program 100.0%

                                                \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                              2. Add Preprocessing
                                              3. Taylor expanded in a around 0

                                                \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                              4. Step-by-step derivation
                                                1. lower-/.f64N/A

                                                  \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                2. +-commutativeN/A

                                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                3. lower-+.f64N/A

                                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                4. lower-exp.f64100.0

                                                  \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                              5. Applied rewrites100.0%

                                                \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                              6. Taylor expanded in b around 0

                                                \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + \frac{1}{2} \cdot b\right)}} \]
                                              7. Step-by-step derivation
                                                1. Applied rewrites57.4%

                                                  \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, b, 1\right), \color{blue}{b}, 2\right)} \]
                                              8. Recombined 2 regimes into one program.
                                              9. Add Preprocessing

                                              Alternative 10: 53.1% accurate, 10.9× speedup?

                                              \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 1.22:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\mathsf{fma}\left(b, 0.5, 1\right) \cdot b}\\ \end{array} \end{array} \]
                                              (FPCore (a b)
                                               :precision binary64
                                               (if (<= b 1.22)
                                                 (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0))
                                                 (/ 1.0 (* (fma b 0.5 1.0) b))))
                                              double code(double a, double b) {
                                              	double tmp;
                                              	if (b <= 1.22) {
                                              		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                              	} else {
                                              		tmp = 1.0 / (fma(b, 0.5, 1.0) * b);
                                              	}
                                              	return tmp;
                                              }
                                              
                                              function code(a, b)
                                              	tmp = 0.0
                                              	if (b <= 1.22)
                                              		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                                              	else
                                              		tmp = Float64(1.0 / Float64(fma(b, 0.5, 1.0) * b));
                                              	end
                                              	return tmp
                                              end
                                              
                                              code[a_, b_] := If[LessEqual[b, 1.22], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(b * 0.5 + 1.0), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision]]
                                              
                                              \begin{array}{l}
                                              
                                              \\
                                              \begin{array}{l}
                                              \mathbf{if}\;b \leq 1.22:\\
                                              \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                                              
                                              \mathbf{else}:\\
                                              \;\;\;\;\frac{1}{\mathsf{fma}\left(b, 0.5, 1\right) \cdot b}\\
                                              
                                              
                                              \end{array}
                                              \end{array}
                                              
                                              Derivation
                                              1. Split input into 2 regimes
                                              2. if b < 1.21999999999999997

                                                1. Initial program 98.9%

                                                  \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                2. Add Preprocessing
                                                3. Taylor expanded in b around 0

                                                  \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                4. Step-by-step derivation
                                                  1. Applied rewrites73.8%

                                                    \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                  2. Taylor expanded in a around 0

                                                    \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                  3. Step-by-step derivation
                                                    1. lower-+.f6473.1

                                                      \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                  4. Applied rewrites73.1%

                                                    \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                  5. Taylor expanded in a around 0

                                                    \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                                  6. Step-by-step derivation
                                                    1. lower-+.f6451.4

                                                      \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                                  7. Applied rewrites51.4%

                                                    \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                                                  if 1.21999999999999997 < b

                                                  1. Initial program 100.0%

                                                    \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                  2. Add Preprocessing
                                                  3. Taylor expanded in a around 0

                                                    \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                  4. Step-by-step derivation
                                                    1. lower-/.f64N/A

                                                      \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                    2. +-commutativeN/A

                                                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                    3. lower-+.f64N/A

                                                      \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                    4. lower-exp.f64100.0

                                                      \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                                  5. Applied rewrites100.0%

                                                    \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                                  6. Taylor expanded in b around 0

                                                    \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + \frac{1}{2} \cdot b\right)}} \]
                                                  7. Step-by-step derivation
                                                    1. Applied rewrites57.0%

                                                      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, b, 1\right), \color{blue}{b}, 2\right)} \]
                                                    2. Taylor expanded in b around inf

                                                      \[\leadsto \frac{1}{{b}^{2} \cdot \left(\frac{1}{2} + \color{blue}{\frac{1}{b}}\right)} \]
                                                    3. Step-by-step derivation
                                                      1. Applied rewrites57.0%

                                                        \[\leadsto \frac{1}{\mathsf{fma}\left(b, 0.5, 1\right) \cdot b} \]
                                                    4. Recombined 2 regimes into one program.
                                                    5. Add Preprocessing

                                                    Alternative 11: 53.1% accurate, 11.2× speedup?

                                                    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 2:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(0.5 \cdot b\right) \cdot b}\\ \end{array} \end{array} \]
                                                    (FPCore (a b)
                                                     :precision binary64
                                                     (if (<= b 2.0) (/ (+ 1.0 a) (+ (+ 1.0 a) 1.0)) (/ 1.0 (* (* 0.5 b) b))))
                                                    double code(double a, double b) {
                                                    	double tmp;
                                                    	if (b <= 2.0) {
                                                    		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                                    	} else {
                                                    		tmp = 1.0 / ((0.5 * b) * b);
                                                    	}
                                                    	return tmp;
                                                    }
                                                    
                                                    real(8) function code(a, b)
                                                        real(8), intent (in) :: a
                                                        real(8), intent (in) :: b
                                                        real(8) :: tmp
                                                        if (b <= 2.0d0) then
                                                            tmp = (1.0d0 + a) / ((1.0d0 + a) + 1.0d0)
                                                        else
                                                            tmp = 1.0d0 / ((0.5d0 * b) * b)
                                                        end if
                                                        code = tmp
                                                    end function
                                                    
                                                    public static double code(double a, double b) {
                                                    	double tmp;
                                                    	if (b <= 2.0) {
                                                    		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                                    	} else {
                                                    		tmp = 1.0 / ((0.5 * b) * b);
                                                    	}
                                                    	return tmp;
                                                    }
                                                    
                                                    def code(a, b):
                                                    	tmp = 0
                                                    	if b <= 2.0:
                                                    		tmp = (1.0 + a) / ((1.0 + a) + 1.0)
                                                    	else:
                                                    		tmp = 1.0 / ((0.5 * b) * b)
                                                    	return tmp
                                                    
                                                    function code(a, b)
                                                    	tmp = 0.0
                                                    	if (b <= 2.0)
                                                    		tmp = Float64(Float64(1.0 + a) / Float64(Float64(1.0 + a) + 1.0));
                                                    	else
                                                    		tmp = Float64(1.0 / Float64(Float64(0.5 * b) * b));
                                                    	end
                                                    	return tmp
                                                    end
                                                    
                                                    function tmp_2 = code(a, b)
                                                    	tmp = 0.0;
                                                    	if (b <= 2.0)
                                                    		tmp = (1.0 + a) / ((1.0 + a) + 1.0);
                                                    	else
                                                    		tmp = 1.0 / ((0.5 * b) * b);
                                                    	end
                                                    	tmp_2 = tmp;
                                                    end
                                                    
                                                    code[a_, b_] := If[LessEqual[b, 2.0], N[(N[(1.0 + a), $MachinePrecision] / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(0.5 * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision]]
                                                    
                                                    \begin{array}{l}
                                                    
                                                    \\
                                                    \begin{array}{l}
                                                    \mathbf{if}\;b \leq 2:\\
                                                    \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\
                                                    
                                                    \mathbf{else}:\\
                                                    \;\;\;\;\frac{1}{\left(0.5 \cdot b\right) \cdot b}\\
                                                    
                                                    
                                                    \end{array}
                                                    \end{array}
                                                    
                                                    Derivation
                                                    1. Split input into 2 regimes
                                                    2. if b < 2

                                                      1. Initial program 98.9%

                                                        \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                      2. Add Preprocessing
                                                      3. Taylor expanded in b around 0

                                                        \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                      4. Step-by-step derivation
                                                        1. Applied rewrites73.8%

                                                          \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                        2. Taylor expanded in a around 0

                                                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                        3. Step-by-step derivation
                                                          1. lower-+.f6473.1

                                                            \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                        4. Applied rewrites73.1%

                                                          \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                        5. Taylor expanded in a around 0

                                                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                                        6. Step-by-step derivation
                                                          1. lower-+.f6451.4

                                                            \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]
                                                        7. Applied rewrites51.4%

                                                          \[\leadsto \frac{\color{blue}{1 + a}}{\left(1 + a\right) + 1} \]

                                                        if 2 < b

                                                        1. Initial program 100.0%

                                                          \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                        2. Add Preprocessing
                                                        3. Taylor expanded in a around 0

                                                          \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                        4. Step-by-step derivation
                                                          1. lower-/.f64N/A

                                                            \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                          2. +-commutativeN/A

                                                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                          3. lower-+.f64N/A

                                                            \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                          4. lower-exp.f64100.0

                                                            \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                                        5. Applied rewrites100.0%

                                                          \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                                        6. Taylor expanded in b around 0

                                                          \[\leadsto \frac{1}{2 + \color{blue}{b \cdot \left(1 + \frac{1}{2} \cdot b\right)}} \]
                                                        7. Step-by-step derivation
                                                          1. Applied rewrites57.0%

                                                            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.5, b, 1\right), \color{blue}{b}, 2\right)} \]
                                                          2. Taylor expanded in b around inf

                                                            \[\leadsto \frac{1}{\frac{1}{2} \cdot {b}^{\color{blue}{2}}} \]
                                                          3. Step-by-step derivation
                                                            1. Applied rewrites57.0%

                                                              \[\leadsto \frac{1}{\left(b \cdot 0.5\right) \cdot b} \]
                                                          4. Recombined 2 regimes into one program.
                                                          5. Final simplification53.1%

                                                            \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq 2:\\ \;\;\;\;\frac{1 + a}{\left(1 + a\right) + 1}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(0.5 \cdot b\right) \cdot b}\\ \end{array} \]
                                                          6. Add Preprocessing

                                                          Alternative 12: 38.7% accurate, 17.5× speedup?

                                                          \[\begin{array}{l} \\ \frac{1}{\left(1 + a\right) + 1} \end{array} \]
                                                          (FPCore (a b) :precision binary64 (/ 1.0 (+ (+ 1.0 a) 1.0)))
                                                          double code(double a, double b) {
                                                          	return 1.0 / ((1.0 + a) + 1.0);
                                                          }
                                                          
                                                          real(8) function code(a, b)
                                                              real(8), intent (in) :: a
                                                              real(8), intent (in) :: b
                                                              code = 1.0d0 / ((1.0d0 + a) + 1.0d0)
                                                          end function
                                                          
                                                          public static double code(double a, double b) {
                                                          	return 1.0 / ((1.0 + a) + 1.0);
                                                          }
                                                          
                                                          def code(a, b):
                                                          	return 1.0 / ((1.0 + a) + 1.0)
                                                          
                                                          function code(a, b)
                                                          	return Float64(1.0 / Float64(Float64(1.0 + a) + 1.0))
                                                          end
                                                          
                                                          function tmp = code(a, b)
                                                          	tmp = 1.0 / ((1.0 + a) + 1.0);
                                                          end
                                                          
                                                          code[a_, b_] := N[(1.0 / N[(N[(1.0 + a), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]
                                                          
                                                          \begin{array}{l}
                                                          
                                                          \\
                                                          \frac{1}{\left(1 + a\right) + 1}
                                                          \end{array}
                                                          
                                                          Derivation
                                                          1. Initial program 99.2%

                                                            \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                          2. Add Preprocessing
                                                          3. Taylor expanded in b around 0

                                                            \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                          4. Step-by-step derivation
                                                            1. Applied rewrites65.0%

                                                              \[\leadsto \frac{e^{a}}{e^{a} + \color{blue}{1}} \]
                                                            2. Taylor expanded in a around 0

                                                              \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                            3. Step-by-step derivation
                                                              1. lower-+.f6464.5

                                                                \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                            4. Applied rewrites64.5%

                                                              \[\leadsto \frac{e^{a}}{\color{blue}{\left(1 + a\right)} + 1} \]
                                                            5. Taylor expanded in a around 0

                                                              \[\leadsto \frac{\color{blue}{1}}{\left(1 + a\right) + 1} \]
                                                            6. Step-by-step derivation
                                                              1. Applied rewrites36.9%

                                                                \[\leadsto \frac{\color{blue}{1}}{\left(1 + a\right) + 1} \]
                                                              2. Add Preprocessing

                                                              Alternative 13: 38.3% accurate, 315.0× speedup?

                                                              \[\begin{array}{l} \\ 0.5 \end{array} \]
                                                              (FPCore (a b) :precision binary64 0.5)
                                                              double code(double a, double b) {
                                                              	return 0.5;
                                                              }
                                                              
                                                              real(8) function code(a, b)
                                                                  real(8), intent (in) :: a
                                                                  real(8), intent (in) :: b
                                                                  code = 0.5d0
                                                              end function
                                                              
                                                              public static double code(double a, double b) {
                                                              	return 0.5;
                                                              }
                                                              
                                                              def code(a, b):
                                                              	return 0.5
                                                              
                                                              function code(a, b)
                                                              	return 0.5
                                                              end
                                                              
                                                              function tmp = code(a, b)
                                                              	tmp = 0.5;
                                                              end
                                                              
                                                              code[a_, b_] := 0.5
                                                              
                                                              \begin{array}{l}
                                                              
                                                              \\
                                                              0.5
                                                              \end{array}
                                                              
                                                              Derivation
                                                              1. Initial program 99.2%

                                                                \[\frac{e^{a}}{e^{a} + e^{b}} \]
                                                              2. Add Preprocessing
                                                              3. Taylor expanded in a around 0

                                                                \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                              4. Step-by-step derivation
                                                                1. lower-/.f64N/A

                                                                  \[\leadsto \color{blue}{\frac{1}{1 + e^{b}}} \]
                                                                2. +-commutativeN/A

                                                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                                3. lower-+.f64N/A

                                                                  \[\leadsto \frac{1}{\color{blue}{e^{b} + 1}} \]
                                                                4. lower-exp.f6483.2

                                                                  \[\leadsto \frac{1}{\color{blue}{e^{b}} + 1} \]
                                                              5. Applied rewrites83.2%

                                                                \[\leadsto \color{blue}{\frac{1}{e^{b} + 1}} \]
                                                              6. Taylor expanded in b around 0

                                                                \[\leadsto \frac{1}{2} \]
                                                              7. Step-by-step derivation
                                                                1. Applied rewrites36.3%

                                                                  \[\leadsto 0.5 \]
                                                                2. Add Preprocessing

                                                                Developer Target 1: 100.0% accurate, 2.7× speedup?

                                                                \[\begin{array}{l} \\ \frac{1}{1 + e^{b - a}} \end{array} \]
                                                                (FPCore (a b) :precision binary64 (/ 1.0 (+ 1.0 (exp (- b a)))))
                                                                double code(double a, double b) {
                                                                	return 1.0 / (1.0 + exp((b - a)));
                                                                }
                                                                
                                                                real(8) function code(a, b)
                                                                    real(8), intent (in) :: a
                                                                    real(8), intent (in) :: b
                                                                    code = 1.0d0 / (1.0d0 + exp((b - a)))
                                                                end function
                                                                
                                                                public static double code(double a, double b) {
                                                                	return 1.0 / (1.0 + Math.exp((b - a)));
                                                                }
                                                                
                                                                def code(a, b):
                                                                	return 1.0 / (1.0 + math.exp((b - a)))
                                                                
                                                                function code(a, b)
                                                                	return Float64(1.0 / Float64(1.0 + exp(Float64(b - a))))
                                                                end
                                                                
                                                                function tmp = code(a, b)
                                                                	tmp = 1.0 / (1.0 + exp((b - a)));
                                                                end
                                                                
                                                                code[a_, b_] := N[(1.0 / N[(1.0 + N[Exp[N[(b - a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
                                                                
                                                                \begin{array}{l}
                                                                
                                                                \\
                                                                \frac{1}{1 + e^{b - a}}
                                                                \end{array}
                                                                

                                                                Reproduce

                                                                ?
                                                                herbie shell --seed 2024254 
                                                                (FPCore (a b)
                                                                  :name "Quotient of sum of exps"
                                                                  :precision binary64
                                                                
                                                                  :alt
                                                                  (! :herbie-platform default (/ 1 (+ 1 (exp (- b a)))))
                                                                
                                                                  (/ (exp a) (+ (exp a) (exp b))))