Octave 3.8, jcobi/2

Percentage Accurate: 24.7% → 80.1%
Time: 3.7s
Alternatives: 5
Speedup: 4.3×

Specification

?
\[\left(\alpha > -1 \land \beta > -1\right) \land i > 0\]
\[\begin{array}{l} t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\ \frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2} \end{array} \]
(FPCore (alpha beta i)
  :precision binary64
  (let* ((t_0 (+ (+ alpha beta) (* 2.0 i))))
  (/
   (+ (/ (/ (* (+ alpha beta) (- beta alpha)) t_0) (+ t_0 2.0)) 1.0)
   2.0)))
double code(double alpha, double beta, double i) {
	double t_0 = (alpha + beta) + (2.0 * i);
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
}
real(8) function code(alpha, beta, i)
use fmin_fmax_functions
    real(8), intent (in) :: alpha
    real(8), intent (in) :: beta
    real(8), intent (in) :: i
    real(8) :: t_0
    t_0 = (alpha + beta) + (2.0d0 * i)
    code = (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0d0)) + 1.0d0) / 2.0d0
end function
public static double code(double alpha, double beta, double i) {
	double t_0 = (alpha + beta) + (2.0 * i);
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
}
def code(alpha, beta, i):
	t_0 = (alpha + beta) + (2.0 * i)
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0
function code(alpha, beta, i)
	t_0 = Float64(Float64(alpha + beta) + Float64(2.0 * i))
	return Float64(Float64(Float64(Float64(Float64(Float64(alpha + beta) * Float64(beta - alpha)) / t_0) / Float64(t_0 + 2.0)) + 1.0) / 2.0)
end
function tmp = code(alpha, beta, i)
	t_0 = (alpha + beta) + (2.0 * i);
	tmp = (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
end
code[alpha_, beta_, i_] := Block[{t$95$0 = N[(N[(alpha + beta), $MachinePrecision] + N[(2.0 * i), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[(N[(alpha + beta), $MachinePrecision] * N[(beta - alpha), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] / N[(t$95$0 + 2.0), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / 2.0), $MachinePrecision]]
\begin{array}{l}
t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\
\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2}
\end{array}

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 5 alternatives:

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

Initial Program: 24.7% accurate, 1.0× speedup?

\[\begin{array}{l} t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\ \frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2} \end{array} \]
(FPCore (alpha beta i)
  :precision binary64
  (let* ((t_0 (+ (+ alpha beta) (* 2.0 i))))
  (/
   (+ (/ (/ (* (+ alpha beta) (- beta alpha)) t_0) (+ t_0 2.0)) 1.0)
   2.0)))
double code(double alpha, double beta, double i) {
	double t_0 = (alpha + beta) + (2.0 * i);
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
}
real(8) function code(alpha, beta, i)
use fmin_fmax_functions
    real(8), intent (in) :: alpha
    real(8), intent (in) :: beta
    real(8), intent (in) :: i
    real(8) :: t_0
    t_0 = (alpha + beta) + (2.0d0 * i)
    code = (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0d0)) + 1.0d0) / 2.0d0
end function
public static double code(double alpha, double beta, double i) {
	double t_0 = (alpha + beta) + (2.0 * i);
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
}
def code(alpha, beta, i):
	t_0 = (alpha + beta) + (2.0 * i)
	return (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0
function code(alpha, beta, i)
	t_0 = Float64(Float64(alpha + beta) + Float64(2.0 * i))
	return Float64(Float64(Float64(Float64(Float64(Float64(alpha + beta) * Float64(beta - alpha)) / t_0) / Float64(t_0 + 2.0)) + 1.0) / 2.0)
end
function tmp = code(alpha, beta, i)
	t_0 = (alpha + beta) + (2.0 * i);
	tmp = (((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0;
end
code[alpha_, beta_, i_] := Block[{t$95$0 = N[(N[(alpha + beta), $MachinePrecision] + N[(2.0 * i), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[(N[(alpha + beta), $MachinePrecision] * N[(beta - alpha), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] / N[(t$95$0 + 2.0), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / 2.0), $MachinePrecision]]
\begin{array}{l}
t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\
\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2}
\end{array}

Alternative 1: 80.1% accurate, 1.0× speedup?

\[\begin{array}{l} \mathbf{if}\;i \leq 7.8 \cdot 10^{-292}:\\ \;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{\beta - \alpha}{\mathsf{fma}\left(i, 2, \beta + \alpha\right)}, \frac{\beta + \alpha}{\mathsf{fma}\left(i, 2, \left(\beta + \alpha\right) - -2\right)}, 1\right) \cdot 0.5\\ \end{array} \]
(FPCore (alpha beta i)
  :precision binary64
  (if (<= i 7.8e-292)
  (fma -1.0 0.5 0.5)
  (*
   (fma
    (/ (- beta alpha) (fma i 2.0 (+ beta alpha)))
    (/ (+ beta alpha) (fma i 2.0 (- (+ beta alpha) -2.0)))
    1.0)
   0.5)))
double code(double alpha, double beta, double i) {
	double tmp;
	if (i <= 7.8e-292) {
		tmp = fma(-1.0, 0.5, 0.5);
	} else {
		tmp = fma(((beta - alpha) / fma(i, 2.0, (beta + alpha))), ((beta + alpha) / fma(i, 2.0, ((beta + alpha) - -2.0))), 1.0) * 0.5;
	}
	return tmp;
}
function code(alpha, beta, i)
	tmp = 0.0
	if (i <= 7.8e-292)
		tmp = fma(-1.0, 0.5, 0.5);
	else
		tmp = Float64(fma(Float64(Float64(beta - alpha) / fma(i, 2.0, Float64(beta + alpha))), Float64(Float64(beta + alpha) / fma(i, 2.0, Float64(Float64(beta + alpha) - -2.0))), 1.0) * 0.5);
	end
	return tmp
end
code[alpha_, beta_, i_] := If[LessEqual[i, 7.8e-292], N[(-1.0 * 0.5 + 0.5), $MachinePrecision], N[(N[(N[(N[(beta - alpha), $MachinePrecision] / N[(i * 2.0 + N[(beta + alpha), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(beta + alpha), $MachinePrecision] / N[(i * 2.0 + N[(N[(beta + alpha), $MachinePrecision] - -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}
\mathbf{if}\;i \leq 7.8 \cdot 10^{-292}:\\
\;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\frac{\beta - \alpha}{\mathsf{fma}\left(i, 2, \beta + \alpha\right)}, \frac{\beta + \alpha}{\mathsf{fma}\left(i, 2, \left(\beta + \alpha\right) - -2\right)}, 1\right) \cdot 0.5\\


\end{array}
Derivation
  1. Split input into 2 regimes
  2. if i < 7.8e-292

    1. Initial program 24.7%

      \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
    2. Taylor expanded in alpha around inf

      \[\leadsto \frac{\color{blue}{-1} + 1}{2} \]
    3. Step-by-step derivation
      1. Applied rewrites72.6%

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

          \[\leadsto \color{blue}{\frac{-1 + 1}{2}} \]
        2. lift-+.f64N/A

          \[\leadsto \frac{\color{blue}{-1 + 1}}{2} \]
        3. div-addN/A

          \[\leadsto \color{blue}{\frac{-1}{2} + \frac{1}{2}} \]
        4. mult-flipN/A

          \[\leadsto \color{blue}{-1 \cdot \frac{1}{2}} + \frac{1}{2} \]
        5. metadata-evalN/A

          \[\leadsto -1 \cdot \color{blue}{\frac{1}{2}} + \frac{1}{2} \]
        6. metadata-evalN/A

          \[\leadsto -1 \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}} \]
        7. lower-fma.f6472.6%

          \[\leadsto \color{blue}{\mathsf{fma}\left(-1, 0.5, 0.5\right)} \]
      3. Applied rewrites72.6%

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

      if 7.8e-292 < i

      1. Initial program 24.7%

        \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
      2. Step-by-step derivation
        1. lift-/.f64N/A

          \[\leadsto \color{blue}{\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2}} \]
        2. mult-flipN/A

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

          \[\leadsto \color{blue}{\left(\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1\right) \cdot \frac{1}{2}} \]
      3. Applied rewrites21.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\beta - \alpha, \frac{\beta + \alpha}{\left(\mathsf{fma}\left(i, 2, \beta + \alpha\right) - -2\right) \cdot \mathsf{fma}\left(i, 2, \beta + \alpha\right)}, 1\right) \cdot 0.5} \]
      4. Step-by-step derivation
        1. lift-fma.f64N/A

          \[\leadsto \color{blue}{\left(\left(\beta - \alpha\right) \cdot \frac{\beta + \alpha}{\left(\mathsf{fma}\left(i, 2, \beta + \alpha\right) - -2\right) \cdot \mathsf{fma}\left(i, 2, \beta + \alpha\right)} + 1\right)} \cdot \frac{1}{2} \]
      5. Applied rewrites45.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\beta - \alpha}{\mathsf{fma}\left(i, 2, \beta + \alpha\right)}, \frac{\beta + \alpha}{\mathsf{fma}\left(i, 2, \left(\beta + \alpha\right) - -2\right)}, 1\right)} \cdot 0.5 \]
    4. Recombined 2 regimes into one program.
    5. Add Preprocessing

    Alternative 2: 79.0% accurate, 1.7× speedup?

    \[\begin{array}{l} \mathbf{if}\;i \leq 7.8 \cdot 10^{-292}:\\ \;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\ \mathbf{elif}\;i \leq 6.4 \cdot 10^{+233}:\\ \;\;\;\;\mathsf{fma}\left(\frac{\alpha - \beta}{-2 - \left(\beta + \alpha\right)}, 0.5, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.5\\ \end{array} \]
    (FPCore (alpha beta i)
      :precision binary64
      (if (<= i 7.8e-292)
      (fma -1.0 0.5 0.5)
      (if (<= i 6.4e+233)
        (fma (/ (- alpha beta) (- -2.0 (+ beta alpha))) 0.5 0.5)
        0.5)))
    double code(double alpha, double beta, double i) {
    	double tmp;
    	if (i <= 7.8e-292) {
    		tmp = fma(-1.0, 0.5, 0.5);
    	} else if (i <= 6.4e+233) {
    		tmp = fma(((alpha - beta) / (-2.0 - (beta + alpha))), 0.5, 0.5);
    	} else {
    		tmp = 0.5;
    	}
    	return tmp;
    }
    
    function code(alpha, beta, i)
    	tmp = 0.0
    	if (i <= 7.8e-292)
    		tmp = fma(-1.0, 0.5, 0.5);
    	elseif (i <= 6.4e+233)
    		tmp = fma(Float64(Float64(alpha - beta) / Float64(-2.0 - Float64(beta + alpha))), 0.5, 0.5);
    	else
    		tmp = 0.5;
    	end
    	return tmp
    end
    
    code[alpha_, beta_, i_] := If[LessEqual[i, 7.8e-292], N[(-1.0 * 0.5 + 0.5), $MachinePrecision], If[LessEqual[i, 6.4e+233], N[(N[(N[(alpha - beta), $MachinePrecision] / N[(-2.0 - N[(beta + alpha), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.5 + 0.5), $MachinePrecision], 0.5]]
    
    \begin{array}{l}
    \mathbf{if}\;i \leq 7.8 \cdot 10^{-292}:\\
    \;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\
    
    \mathbf{elif}\;i \leq 6.4 \cdot 10^{+233}:\\
    \;\;\;\;\mathsf{fma}\left(\frac{\alpha - \beta}{-2 - \left(\beta + \alpha\right)}, 0.5, 0.5\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;0.5\\
    
    
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if i < 7.8e-292

      1. Initial program 24.7%

        \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
      2. Taylor expanded in alpha around inf

        \[\leadsto \frac{\color{blue}{-1} + 1}{2} \]
      3. Step-by-step derivation
        1. Applied rewrites72.6%

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

            \[\leadsto \color{blue}{\frac{-1 + 1}{2}} \]
          2. lift-+.f64N/A

            \[\leadsto \frac{\color{blue}{-1 + 1}}{2} \]
          3. div-addN/A

            \[\leadsto \color{blue}{\frac{-1}{2} + \frac{1}{2}} \]
          4. mult-flipN/A

            \[\leadsto \color{blue}{-1 \cdot \frac{1}{2}} + \frac{1}{2} \]
          5. metadata-evalN/A

            \[\leadsto -1 \cdot \color{blue}{\frac{1}{2}} + \frac{1}{2} \]
          6. metadata-evalN/A

            \[\leadsto -1 \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}} \]
          7. lower-fma.f6472.6%

            \[\leadsto \color{blue}{\mathsf{fma}\left(-1, 0.5, 0.5\right)} \]
        3. Applied rewrites72.6%

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

        if 7.8e-292 < i < 6.4000000000000004e233

        1. Initial program 24.7%

          \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
        2. Taylor expanded in i around 0

          \[\leadsto \frac{\color{blue}{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}} + 1}{2} \]
        3. Step-by-step derivation
          1. lower-/.f64N/A

            \[\leadsto \frac{\frac{\beta - \alpha}{\color{blue}{2 + \left(\alpha + \beta\right)}} + 1}{2} \]
          2. lower--.f64N/A

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

            \[\leadsto \frac{\frac{\beta - \alpha}{2 + \color{blue}{\left(\alpha + \beta\right)}} + 1}{2} \]
          4. lower-+.f6447.5%

            \[\leadsto \frac{\frac{\beta - \alpha}{2 + \left(\alpha + \color{blue}{\beta}\right)} + 1}{2} \]
        4. Applied rewrites47.5%

          \[\leadsto \frac{\color{blue}{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}} + 1}{2} \]
        5. Step-by-step derivation
          1. lift-/.f64N/A

            \[\leadsto \color{blue}{\frac{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} + 1}{2}} \]
          2. lift-+.f64N/A

            \[\leadsto \frac{\color{blue}{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} + 1}}{2} \]
          3. div-addN/A

            \[\leadsto \color{blue}{\frac{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}}{2} + \frac{1}{2}} \]
          4. mult-flipN/A

            \[\leadsto \color{blue}{\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \cdot \frac{1}{2}} + \frac{1}{2} \]
          5. metadata-evalN/A

            \[\leadsto \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \cdot \color{blue}{\frac{1}{2}} + \frac{1}{2} \]
          6. metadata-evalN/A

            \[\leadsto \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}} \]
          7. lower-fma.f6447.5%

            \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}, 0.5, 0.5\right)} \]
        6. Applied rewrites47.5%

          \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\alpha - \beta}{-2 - \left(\beta + \alpha\right)}, 0.5, 0.5\right)} \]

        if 6.4000000000000004e233 < i

        1. Initial program 24.7%

          \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
        2. Taylor expanded in i around inf

          \[\leadsto \color{blue}{\frac{1}{2}} \]
        3. Step-by-step derivation
          1. Applied rewrites19.7%

            \[\leadsto \color{blue}{0.5} \]
        4. Recombined 3 regimes into one program.
        5. Add Preprocessing

        Alternative 3: 73.3% accurate, 4.3× speedup?

        \[\begin{array}{l} \mathbf{if}\;i \leq 1.35 \cdot 10^{+231}:\\ \;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.5\\ \end{array} \]
        (FPCore (alpha beta i)
          :precision binary64
          (if (<= i 1.35e+231) (fma -1.0 0.5 0.5) 0.5))
        double code(double alpha, double beta, double i) {
        	double tmp;
        	if (i <= 1.35e+231) {
        		tmp = fma(-1.0, 0.5, 0.5);
        	} else {
        		tmp = 0.5;
        	}
        	return tmp;
        }
        
        function code(alpha, beta, i)
        	tmp = 0.0
        	if (i <= 1.35e+231)
        		tmp = fma(-1.0, 0.5, 0.5);
        	else
        		tmp = 0.5;
        	end
        	return tmp
        end
        
        code[alpha_, beta_, i_] := If[LessEqual[i, 1.35e+231], N[(-1.0 * 0.5 + 0.5), $MachinePrecision], 0.5]
        
        \begin{array}{l}
        \mathbf{if}\;i \leq 1.35 \cdot 10^{+231}:\\
        \;\;\;\;\mathsf{fma}\left(-1, 0.5, 0.5\right)\\
        
        \mathbf{else}:\\
        \;\;\;\;0.5\\
        
        
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if i < 1.35e231

          1. Initial program 24.7%

            \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
          2. Taylor expanded in alpha around inf

            \[\leadsto \frac{\color{blue}{-1} + 1}{2} \]
          3. Step-by-step derivation
            1. Applied rewrites72.6%

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

                \[\leadsto \color{blue}{\frac{-1 + 1}{2}} \]
              2. lift-+.f64N/A

                \[\leadsto \frac{\color{blue}{-1 + 1}}{2} \]
              3. div-addN/A

                \[\leadsto \color{blue}{\frac{-1}{2} + \frac{1}{2}} \]
              4. mult-flipN/A

                \[\leadsto \color{blue}{-1 \cdot \frac{1}{2}} + \frac{1}{2} \]
              5. metadata-evalN/A

                \[\leadsto -1 \cdot \color{blue}{\frac{1}{2}} + \frac{1}{2} \]
              6. metadata-evalN/A

                \[\leadsto -1 \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}} \]
              7. lower-fma.f6472.6%

                \[\leadsto \color{blue}{\mathsf{fma}\left(-1, 0.5, 0.5\right)} \]
            3. Applied rewrites72.6%

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

            if 1.35e231 < i

            1. Initial program 24.7%

              \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
            2. Taylor expanded in i around inf

              \[\leadsto \color{blue}{\frac{1}{2}} \]
            3. Step-by-step derivation
              1. Applied rewrites19.7%

                \[\leadsto \color{blue}{0.5} \]
            4. Recombined 2 regimes into one program.
            5. Add Preprocessing

            Alternative 4: 23.8% accurate, 0.9× speedup?

            \[\begin{array}{l} t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\ \mathbf{if}\;\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2} \leq 0.6:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;2 \cdot 0.5\\ \end{array} \]
            (FPCore (alpha beta i)
              :precision binary64
              (let* ((t_0 (+ (+ alpha beta) (* 2.0 i))))
              (if (<=
                   (/
                    (+
                     (/ (/ (* (+ alpha beta) (- beta alpha)) t_0) (+ t_0 2.0))
                     1.0)
                    2.0)
                   0.6)
                0.5
                (* 2.0 0.5))))
            double code(double alpha, double beta, double i) {
            	double t_0 = (alpha + beta) + (2.0 * i);
            	double tmp;
            	if (((((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0) <= 0.6) {
            		tmp = 0.5;
            	} else {
            		tmp = 2.0 * 0.5;
            	}
            	return tmp;
            }
            
            real(8) function code(alpha, beta, i)
            use fmin_fmax_functions
                real(8), intent (in) :: alpha
                real(8), intent (in) :: beta
                real(8), intent (in) :: i
                real(8) :: t_0
                real(8) :: tmp
                t_0 = (alpha + beta) + (2.0d0 * i)
                if (((((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0d0)) + 1.0d0) / 2.0d0) <= 0.6d0) then
                    tmp = 0.5d0
                else
                    tmp = 2.0d0 * 0.5d0
                end if
                code = tmp
            end function
            
            public static double code(double alpha, double beta, double i) {
            	double t_0 = (alpha + beta) + (2.0 * i);
            	double tmp;
            	if (((((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0) <= 0.6) {
            		tmp = 0.5;
            	} else {
            		tmp = 2.0 * 0.5;
            	}
            	return tmp;
            }
            
            def code(alpha, beta, i):
            	t_0 = (alpha + beta) + (2.0 * i)
            	tmp = 0
            	if ((((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0) <= 0.6:
            		tmp = 0.5
            	else:
            		tmp = 2.0 * 0.5
            	return tmp
            
            function code(alpha, beta, i)
            	t_0 = Float64(Float64(alpha + beta) + Float64(2.0 * i))
            	tmp = 0.0
            	if (Float64(Float64(Float64(Float64(Float64(Float64(alpha + beta) * Float64(beta - alpha)) / t_0) / Float64(t_0 + 2.0)) + 1.0) / 2.0) <= 0.6)
            		tmp = 0.5;
            	else
            		tmp = Float64(2.0 * 0.5);
            	end
            	return tmp
            end
            
            function tmp_2 = code(alpha, beta, i)
            	t_0 = (alpha + beta) + (2.0 * i);
            	tmp = 0.0;
            	if (((((((alpha + beta) * (beta - alpha)) / t_0) / (t_0 + 2.0)) + 1.0) / 2.0) <= 0.6)
            		tmp = 0.5;
            	else
            		tmp = 2.0 * 0.5;
            	end
            	tmp_2 = tmp;
            end
            
            code[alpha_, beta_, i_] := Block[{t$95$0 = N[(N[(alpha + beta), $MachinePrecision] + N[(2.0 * i), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(N[(N[(N[(N[(alpha + beta), $MachinePrecision] * N[(beta - alpha), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] / N[(t$95$0 + 2.0), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / 2.0), $MachinePrecision], 0.6], 0.5, N[(2.0 * 0.5), $MachinePrecision]]]
            
            \begin{array}{l}
            t_0 := \left(\alpha + \beta\right) + 2 \cdot i\\
            \mathbf{if}\;\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{t\_0}}{t\_0 + 2} + 1}{2} \leq 0.6:\\
            \;\;\;\;0.5\\
            
            \mathbf{else}:\\
            \;\;\;\;2 \cdot 0.5\\
            
            
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if (/.f64 (+.f64 (/.f64 (/.f64 (*.f64 (+.f64 alpha beta) (-.f64 beta alpha)) (+.f64 (+.f64 alpha beta) (*.f64 #s(literal 2 binary64) i))) (+.f64 (+.f64 (+.f64 alpha beta) (*.f64 #s(literal 2 binary64) i)) #s(literal 2 binary64))) #s(literal 1 binary64)) #s(literal 2 binary64)) < 0.59999999999999998

              1. Initial program 24.7%

                \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
              2. Taylor expanded in i around inf

                \[\leadsto \color{blue}{\frac{1}{2}} \]
              3. Step-by-step derivation
                1. Applied rewrites19.7%

                  \[\leadsto \color{blue}{0.5} \]

                if 0.59999999999999998 < (/.f64 (+.f64 (/.f64 (/.f64 (*.f64 (+.f64 alpha beta) (-.f64 beta alpha)) (+.f64 (+.f64 alpha beta) (*.f64 #s(literal 2 binary64) i))) (+.f64 (+.f64 (+.f64 alpha beta) (*.f64 #s(literal 2 binary64) i)) #s(literal 2 binary64))) #s(literal 1 binary64)) #s(literal 2 binary64))

                1. Initial program 24.7%

                  \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
                2. Step-by-step derivation
                  1. lift-/.f64N/A

                    \[\leadsto \color{blue}{\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2}} \]
                  2. mult-flipN/A

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

                    \[\leadsto \color{blue}{\left(\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1\right) \cdot \frac{1}{2}} \]
                3. Applied rewrites21.7%

                  \[\leadsto \color{blue}{\mathsf{fma}\left(\beta - \alpha, \frac{\beta + \alpha}{\left(\mathsf{fma}\left(i, 2, \beta + \alpha\right) - -2\right) \cdot \mathsf{fma}\left(i, 2, \beta + \alpha\right)}, 1\right) \cdot 0.5} \]
                4. Taylor expanded in beta around inf

                  \[\leadsto \color{blue}{2} \cdot 0.5 \]
                5. Step-by-step derivation
                  1. Applied rewrites11.3%

                    \[\leadsto \color{blue}{2} \cdot 0.5 \]
                6. Recombined 2 regimes into one program.
                7. Add Preprocessing

                Alternative 5: 19.7% accurate, 42.2× speedup?

                \[0.5 \]
                (FPCore (alpha beta i)
                  :precision binary64
                  0.5)
                double code(double alpha, double beta, double i) {
                	return 0.5;
                }
                
                real(8) function code(alpha, beta, i)
                use fmin_fmax_functions
                    real(8), intent (in) :: alpha
                    real(8), intent (in) :: beta
                    real(8), intent (in) :: i
                    code = 0.5d0
                end function
                
                public static double code(double alpha, double beta, double i) {
                	return 0.5;
                }
                
                def code(alpha, beta, i):
                	return 0.5
                
                function code(alpha, beta, i)
                	return 0.5
                end
                
                function tmp = code(alpha, beta, i)
                	tmp = 0.5;
                end
                
                code[alpha_, beta_, i_] := 0.5
                
                0.5
                
                Derivation
                1. Initial program 24.7%

                  \[\frac{\frac{\frac{\left(\alpha + \beta\right) \cdot \left(\beta - \alpha\right)}{\left(\alpha + \beta\right) + 2 \cdot i}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) + 2} + 1}{2} \]
                2. Taylor expanded in i around inf

                  \[\leadsto \color{blue}{\frac{1}{2}} \]
                3. Step-by-step derivation
                  1. Applied rewrites19.7%

                    \[\leadsto \color{blue}{0.5} \]
                  2. Add Preprocessing

                  Reproduce

                  ?
                  herbie shell --seed 2025313 -o setup:search
                  (FPCore (alpha beta i)
                    :name "Octave 3.8, jcobi/2"
                    :precision binary64
                    :pre (and (and (> alpha -1.0) (> beta -1.0)) (> i 0.0))
                    (/ (+ (/ (/ (* (+ alpha beta) (- beta alpha)) (+ (+ alpha beta) (* 2.0 i))) (+ (+ (+ alpha beta) (* 2.0 i)) 2.0)) 1.0) 2.0))