Octave 3.8, jcobi/1

Percentage Accurate: 74.1% → 99.4%
Time: 7.7s
Alternatives: 13
Speedup: 0.7×

Specification

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

\\
\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}
\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: 74.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2} \end{array} \]
(FPCore (alpha beta)
 :precision binary64
 (/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2.0)) 1.0) 2.0))
double code(double alpha, double beta) {
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
}
real(8) function code(alpha, beta)
    real(8), intent (in) :: alpha
    real(8), intent (in) :: beta
    code = (((beta - alpha) / ((alpha + beta) + 2.0d0)) + 1.0d0) / 2.0d0
end function
public static double code(double alpha, double beta) {
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
}
def code(alpha, beta):
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0
function code(alpha, beta)
	return Float64(Float64(Float64(Float64(beta - alpha) / Float64(Float64(alpha + beta) + 2.0)) + 1.0) / 2.0)
end
function tmp = code(alpha, beta)
	tmp = (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
end
code[alpha_, beta_] := N[(N[(N[(N[(beta - alpha), $MachinePrecision] / N[(N[(alpha + beta), $MachinePrecision] + 2.0), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / 2.0), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}
\end{array}

Alternative 1: 99.4% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}\\ \mathbf{if}\;t\_0 \leq -1:\\ \;\;\;\;\frac{1 + \beta}{\alpha}\\ \mathbf{else}:\\ \;\;\;\;\frac{1 + t\_0}{2}\\ \end{array} \end{array} \]
(FPCore (alpha beta)
 :precision binary64
 (let* ((t_0 (/ (- beta alpha) (+ 2.0 (+ alpha beta)))))
   (if (<= t_0 -1.0) (/ (+ 1.0 beta) alpha) (/ (+ 1.0 t_0) 2.0))))
double code(double alpha, double beta) {
	double t_0 = (beta - alpha) / (2.0 + (alpha + beta));
	double tmp;
	if (t_0 <= -1.0) {
		tmp = (1.0 + beta) / alpha;
	} else {
		tmp = (1.0 + t_0) / 2.0;
	}
	return tmp;
}
real(8) function code(alpha, beta)
    real(8), intent (in) :: alpha
    real(8), intent (in) :: beta
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (beta - alpha) / (2.0d0 + (alpha + beta))
    if (t_0 <= (-1.0d0)) then
        tmp = (1.0d0 + beta) / alpha
    else
        tmp = (1.0d0 + t_0) / 2.0d0
    end if
    code = tmp
end function
public static double code(double alpha, double beta) {
	double t_0 = (beta - alpha) / (2.0 + (alpha + beta));
	double tmp;
	if (t_0 <= -1.0) {
		tmp = (1.0 + beta) / alpha;
	} else {
		tmp = (1.0 + t_0) / 2.0;
	}
	return tmp;
}
def code(alpha, beta):
	t_0 = (beta - alpha) / (2.0 + (alpha + beta))
	tmp = 0
	if t_0 <= -1.0:
		tmp = (1.0 + beta) / alpha
	else:
		tmp = (1.0 + t_0) / 2.0
	return tmp
function code(alpha, beta)
	t_0 = Float64(Float64(beta - alpha) / Float64(2.0 + Float64(alpha + beta)))
	tmp = 0.0
	if (t_0 <= -1.0)
		tmp = Float64(Float64(1.0 + beta) / alpha);
	else
		tmp = Float64(Float64(1.0 + t_0) / 2.0);
	end
	return tmp
end
function tmp_2 = code(alpha, beta)
	t_0 = (beta - alpha) / (2.0 + (alpha + beta));
	tmp = 0.0;
	if (t_0 <= -1.0)
		tmp = (1.0 + beta) / alpha;
	else
		tmp = (1.0 + t_0) / 2.0;
	end
	tmp_2 = tmp;
end
code[alpha_, beta_] := Block[{t$95$0 = N[(N[(beta - alpha), $MachinePrecision] / N[(2.0 + N[(alpha + beta), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -1.0], N[(N[(1.0 + beta), $MachinePrecision] / alpha), $MachinePrecision], N[(N[(1.0 + t$95$0), $MachinePrecision] / 2.0), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}\\
\mathbf{if}\;t\_0 \leq -1:\\
\;\;\;\;\frac{1 + \beta}{\alpha}\\

\mathbf{else}:\\
\;\;\;\;\frac{1 + t\_0}{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (-.f64 beta alpha) (+.f64 (+.f64 alpha beta) #s(literal 2 binary64))) < -1

    1. Initial program 5.1%

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

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{2 + 2 \cdot \beta}{\alpha}} \]
    4. Step-by-step derivation
      1. associate-*r/N/A

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

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

        \[\leadsto \frac{\frac{1}{2} \cdot \color{blue}{\left(2 \cdot \beta + 2\right)}}{\alpha} \]
      4. distribute-lft-inN/A

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

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

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

        \[\leadsto \frac{\color{blue}{1} \cdot \beta + 1}{\alpha} \]
      8. *-lft-identityN/A

        \[\leadsto \frac{\color{blue}{\beta} + 1}{\alpha} \]
      9. lower-+.f64100.0

        \[\leadsto \frac{\color{blue}{\beta + 1}}{\alpha} \]
    5. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{\beta + 1}{\alpha}} \]

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

    1. Initial program 100.0%

      \[\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification100.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \leq -1:\\ \;\;\;\;\frac{1 + \beta}{\alpha}\\ \mathbf{else}:\\ \;\;\;\;\frac{1 + \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}}{2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 97.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}\\ \mathbf{if}\;t\_0 \leq -1:\\ \;\;\;\;\frac{1 + \beta}{\alpha}\\ \mathbf{elif}\;t\_0 \leq 0.001:\\ \;\;\;\;\mathsf{fma}\left(\frac{\alpha}{-2 - \alpha}, 0.5, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(1 + \alpha, \frac{-1}{\beta}, 1\right)\\ \end{array} \end{array} \]
(FPCore (alpha beta)
 :precision binary64
 (let* ((t_0 (/ (- beta alpha) (+ 2.0 (+ alpha beta)))))
   (if (<= t_0 -1.0)
     (/ (+ 1.0 beta) alpha)
     (if (<= t_0 0.001)
       (fma (/ alpha (- -2.0 alpha)) 0.5 0.5)
       (fma (+ 1.0 alpha) (/ -1.0 beta) 1.0)))))
double code(double alpha, double beta) {
	double t_0 = (beta - alpha) / (2.0 + (alpha + beta));
	double tmp;
	if (t_0 <= -1.0) {
		tmp = (1.0 + beta) / alpha;
	} else if (t_0 <= 0.001) {
		tmp = fma((alpha / (-2.0 - alpha)), 0.5, 0.5);
	} else {
		tmp = fma((1.0 + alpha), (-1.0 / beta), 1.0);
	}
	return tmp;
}
function code(alpha, beta)
	t_0 = Float64(Float64(beta - alpha) / Float64(2.0 + Float64(alpha + beta)))
	tmp = 0.0
	if (t_0 <= -1.0)
		tmp = Float64(Float64(1.0 + beta) / alpha);
	elseif (t_0 <= 0.001)
		tmp = fma(Float64(alpha / Float64(-2.0 - alpha)), 0.5, 0.5);
	else
		tmp = fma(Float64(1.0 + alpha), Float64(-1.0 / beta), 1.0);
	end
	return tmp
end
code[alpha_, beta_] := Block[{t$95$0 = N[(N[(beta - alpha), $MachinePrecision] / N[(2.0 + N[(alpha + beta), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -1.0], N[(N[(1.0 + beta), $MachinePrecision] / alpha), $MachinePrecision], If[LessEqual[t$95$0, 0.001], N[(N[(alpha / N[(-2.0 - alpha), $MachinePrecision]), $MachinePrecision] * 0.5 + 0.5), $MachinePrecision], N[(N[(1.0 + alpha), $MachinePrecision] * N[(-1.0 / beta), $MachinePrecision] + 1.0), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)}\\
\mathbf{if}\;t\_0 \leq -1:\\
\;\;\;\;\frac{1 + \beta}{\alpha}\\

\mathbf{elif}\;t\_0 \leq 0.001:\\
\;\;\;\;\mathsf{fma}\left(\frac{\alpha}{-2 - \alpha}, 0.5, 0.5\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (/.f64 (-.f64 beta alpha) (+.f64 (+.f64 alpha beta) #s(literal 2 binary64))) < -1

    1. Initial program 5.3%

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

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{2 + 2 \cdot \beta}{\alpha}} \]
    4. Step-by-step derivation
      1. associate-*r/N/A

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

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

        \[\leadsto \frac{\frac{1}{2} \cdot \color{blue}{\left(2 \cdot \beta + 2\right)}}{\alpha} \]
      4. distribute-lft-inN/A

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

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

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

        \[\leadsto \frac{\color{blue}{1} \cdot \beta + 1}{\alpha} \]
      8. *-lft-identityN/A

        \[\leadsto \frac{\color{blue}{\beta} + 1}{\alpha} \]
      9. lower-+.f64100.0

        \[\leadsto \frac{\color{blue}{\beta + 1}}{\alpha} \]
    5. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{\beta + 1}{\alpha}} \]

    if -1 < (/.f64 (-.f64 beta alpha) (+.f64 (+.f64 alpha beta) #s(literal 2 binary64))) < 1e-3

    1. Initial program 98.7%

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

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\frac{\beta}{2 + \beta} + 1\right)} \]
      2. distribute-rgt-inN/A

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

        \[\leadsto \frac{\beta}{2 + \beta} \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}} \]
      4. lower-fma.f64N/A

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

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

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\color{blue}{\beta + 2}}, \frac{1}{2}, \frac{1}{2}\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\beta + \color{blue}{\left(\mathsf{neg}\left(-2\right)\right)}}, \frac{1}{2}, \frac{1}{2}\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\beta + \left(\mathsf{neg}\left(\color{blue}{-1 \cdot 2}\right)\right)}, \frac{1}{2}, \frac{1}{2}\right) \]
      9. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\color{blue}{\beta - -1 \cdot 2}}, \frac{1}{2}, \frac{1}{2}\right) \]
      10. lower--.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\color{blue}{\beta - -1 \cdot 2}}, \frac{1}{2}, \frac{1}{2}\right) \]
      11. metadata-eval95.0

        \[\leadsto \mathsf{fma}\left(\frac{\beta}{\beta - \color{blue}{-2}}, 0.5, 0.5\right) \]
    5. Applied rewrites95.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\beta}{\beta - -2}, 0.5, 0.5\right)} \]
    6. Taylor expanded in beta around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(1 - \frac{\alpha}{2 + \alpha}\right)} \]
    7. Step-by-step derivation
      1. sub-negN/A

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\left(\mathsf{neg}\left(\frac{\alpha}{2 + \alpha}\right)\right) + 1\right)} \]
      3. distribute-rgt-inN/A

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

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\frac{\alpha}{2 + \alpha}\right), \frac{1}{2}, \frac{1}{2}\right)} \]
      6. distribute-neg-frac2N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\alpha}{\mathsf{neg}\left(\left(2 + \alpha\right)\right)}}, \frac{1}{2}, \frac{1}{2}\right) \]
      7. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\alpha}{\mathsf{neg}\left(\left(2 + \alpha\right)\right)}}, \frac{1}{2}, \frac{1}{2}\right) \]
      8. distribute-neg-inN/A

        \[\leadsto \mathsf{fma}\left(\frac{\alpha}{\color{blue}{\left(\mathsf{neg}\left(2\right)\right) + \left(\mathsf{neg}\left(\alpha\right)\right)}}, \frac{1}{2}, \frac{1}{2}\right) \]
      9. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\alpha}{\color{blue}{-2} + \left(\mathsf{neg}\left(\alpha\right)\right)}, \frac{1}{2}, \frac{1}{2}\right) \]
      10. unsub-negN/A

        \[\leadsto \mathsf{fma}\left(\frac{\alpha}{\color{blue}{-2 - \alpha}}, \frac{1}{2}, \frac{1}{2}\right) \]
      11. lower--.f6496.4

        \[\leadsto \mathsf{fma}\left(\frac{\alpha}{\color{blue}{-2 - \alpha}}, 0.5, 0.5\right) \]
    8. Applied rewrites96.4%

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

    if 1e-3 < (/.f64 (-.f64 beta alpha) (+.f64 (+.f64 alpha beta) #s(literal 2 binary64)))

    1. Initial program 100.0%

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

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

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

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

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

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

        \[\leadsto \mathsf{fma}\left(\frac{-1 \cdot \alpha - \color{blue}{\left(\alpha + 2\right)}}{\beta}, \frac{1}{2}, 1\right) \]
      6. associate--r+N/A

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\left(-1 \cdot \alpha - \alpha\right) - 2}}{\beta}, \frac{1}{2}, 1\right) \]
      7. sub-negN/A

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\left(-1 \cdot \alpha - \alpha\right) + \left(\mathsf{neg}\left(2\right)\right)}}{\beta}, \frac{1}{2}, 1\right) \]
      8. *-lft-identityN/A

        \[\leadsto \mathsf{fma}\left(\frac{\left(-1 \cdot \alpha - \color{blue}{1 \cdot \alpha}\right) + \left(\mathsf{neg}\left(2\right)\right)}{\beta}, \frac{1}{2}, 1\right) \]
      9. distribute-rgt-out--N/A

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

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

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

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

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

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

        \[\leadsto \mathsf{fma}\left(\frac{\mathsf{fma}\left(\alpha, \color{blue}{-2}, -1 \cdot 2\right)}{\beta}, \frac{1}{2}, 1\right) \]
      16. metadata-eval97.2

        \[\leadsto \mathsf{fma}\left(\frac{\mathsf{fma}\left(\alpha, -2, \color{blue}{-2}\right)}{\beta}, 0.5, 1\right) \]
    5. Applied rewrites97.2%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\mathsf{fma}\left(\alpha, -2, -2\right)}{\beta}, 0.5, 1\right)} \]
    6. Taylor expanded in alpha around 0

      \[\leadsto \left(1 + -1 \cdot \frac{\alpha}{\beta}\right) - \color{blue}{\frac{1}{\beta}} \]
    7. Step-by-step derivation
      1. Applied rewrites97.2%

        \[\leadsto \mathsf{fma}\left(\alpha + 1, \color{blue}{\frac{-1}{\beta}}, 1\right) \]
    8. Recombined 3 regimes into one program.
    9. Final simplification97.6%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \leq -1:\\ \;\;\;\;\frac{1 + \beta}{\alpha}\\ \mathbf{elif}\;\frac{\beta - \alpha}{2 + \left(\alpha + \beta\right)} \leq 0.001:\\ \;\;\;\;\mathsf{fma}\left(\frac{\alpha}{-2 - \alpha}, 0.5, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(1 + \alpha, \frac{-1}{\beta}, 1\right)\\ \end{array} \]
    10. Add Preprocessing

    Reproduce

    ?
    herbie shell --seed 2024230 
    (FPCore (alpha beta)
      :name "Octave 3.8, jcobi/1"
      :precision binary64
      :pre (and (> alpha -1.0) (> beta -1.0))
      (/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2.0)) 1.0) 2.0))