Numeric.SpecFunctions:incompleteBetaApprox from math-functions-0.1.5.2, B

Percentage Accurate: 96.9% → 99.6%
Time: 8.6s
Alternatives: 6
Speedup: 1.5×

Specification

?
\[\begin{array}{l} \\ x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (* x (exp (+ (* y (- (log z) t)) (* a (- (log (- 1.0 z)) b))))))
double code(double x, double y, double z, double t, double a, double b) {
	return x * exp(((y * (log(z) - t)) + (a * (log((1.0 - z)) - b))));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = x * exp(((y * (log(z) - t)) + (a * (log((1.0d0 - z)) - b))))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return x * Math.exp(((y * (Math.log(z) - t)) + (a * (Math.log((1.0 - z)) - b))));
}
def code(x, y, z, t, a, b):
	return x * math.exp(((y * (math.log(z) - t)) + (a * (math.log((1.0 - z)) - b))))
function code(x, y, z, t, a, b)
	return Float64(x * exp(Float64(Float64(y * Float64(log(z) - t)) + Float64(a * Float64(log(Float64(1.0 - z)) - b)))))
end
function tmp = code(x, y, z, t, a, b)
	tmp = x * exp(((y * (log(z) - t)) + (a * (log((1.0 - z)) - b))));
end
code[x_, y_, z_, t_, a_, b_] := N[(x * N[Exp[N[(N[(y * N[(N[Log[z], $MachinePrecision] - t), $MachinePrecision]), $MachinePrecision] + N[(a * N[(N[Log[N[(1.0 - z), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 6 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: 96.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (* x (exp (+ (* y (- (log z) t)) (* a (- (log (- 1.0 z)) b))))))
double code(double x, double y, double z, double t, double a, double b) {
	return x * exp(((y * (log(z) - t)) + (a * (log((1.0 - z)) - b))));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = x * exp(((y * (log(z) - t)) + (a * (log((1.0d0 - z)) - b))))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return x * Math.exp(((y * (Math.log(z) - t)) + (a * (Math.log((1.0 - z)) - b))));
}
def code(x, y, z, t, a, b):
	return x * math.exp(((y * (math.log(z) - t)) + (a * (math.log((1.0 - z)) - b))))
function code(x, y, z, t, a, b)
	return Float64(x * exp(Float64(Float64(y * Float64(log(z) - t)) + Float64(a * Float64(log(Float64(1.0 - z)) - b)))))
end
function tmp = code(x, y, z, t, a, b)
	tmp = x * exp(((y * (log(z) - t)) + (a * (log((1.0 - z)) - b))));
end
code[x_, y_, z_, t_, a_, b_] := N[(x * N[Exp[N[(N[(y * N[(N[Log[z], $MachinePrecision] - t), $MachinePrecision]), $MachinePrecision] + N[(a * N[(N[Log[N[(1.0 - z), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)}
\end{array}

Alternative 1: 99.6% accurate, 1.5× speedup?

\[\begin{array}{l} \\ x \cdot e^{\mathsf{fma}\left(-a, z + b, \left(\log z - t\right) \cdot y\right)} \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (* x (exp (fma (- a) (+ z b) (* (- (log z) t) y)))))
double code(double x, double y, double z, double t, double a, double b) {
	return x * exp(fma(-a, (z + b), ((log(z) - t) * y)));
}
function code(x, y, z, t, a, b)
	return Float64(x * exp(fma(Float64(-a), Float64(z + b), Float64(Float64(log(z) - t) * y))))
end
code[x_, y_, z_, t_, a_, b_] := N[(x * N[Exp[N[((-a) * N[(z + b), $MachinePrecision] + N[(N[(N[Log[z], $MachinePrecision] - t), $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x \cdot e^{\mathsf{fma}\left(-a, z + b, \left(\log z - t\right) \cdot y\right)}
\end{array}
Derivation
  1. Initial program 94.7%

    \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
  2. Add Preprocessing
  3. Taylor expanded in z around 0

    \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + \left(-1 \cdot \left(a \cdot z\right) + y \cdot \left(\log z - t\right)\right)}} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot b\right) + -1 \cdot \left(a \cdot z\right)\right) + y \cdot \left(\log z - t\right)}} \]
    2. +-commutativeN/A

      \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot z\right) + -1 \cdot \left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
    3. associate-*r*N/A

      \[\leadsto x \cdot e^{\left(\color{blue}{\left(-1 \cdot a\right) \cdot z} + -1 \cdot \left(a \cdot b\right)\right) + y \cdot \left(\log z - t\right)} \]
    4. associate-*r*N/A

      \[\leadsto x \cdot e^{\left(\left(-1 \cdot a\right) \cdot z + \color{blue}{\left(-1 \cdot a\right) \cdot b}\right) + y \cdot \left(\log z - t\right)} \]
    5. distribute-lft-outN/A

      \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot a\right) \cdot \left(z + b\right)} + y \cdot \left(\log z - t\right)} \]
    6. lower-fma.f64N/A

      \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-1 \cdot a, z + b, y \cdot \left(\log z - t\right)\right)}} \]
    7. mul-1-negN/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{\mathsf{neg}\left(a\right)}, z + b, y \cdot \left(\log z - t\right)\right)} \]
    8. lower-neg.f64N/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-a}, z + b, y \cdot \left(\log z - t\right)\right)} \]
    9. lower-+.f64N/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, \color{blue}{z + b}, y \cdot \left(\log z - t\right)\right)} \]
    10. *-commutativeN/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
    11. lower-*.f64N/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
    12. lower--.f64N/A

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
    13. lower-log.f6499.6

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
  5. Applied rewrites99.6%

    \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-a, z + b, \left(\log z - t\right) \cdot y\right)}} \]
  6. Add Preprocessing

Alternative 2: 89.4% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 1.4 \cdot 10^{+187}\right):\\ \;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\mathsf{fma}\left(-b, a, \log z \cdot y\right)}\\ \end{array} \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (if (or (<= t -600.0) (not (<= t 1.4e+187)))
   (* x (exp (* (- y) t)))
   (* x (exp (fma (- b) a (* (log z) y))))))
double code(double x, double y, double z, double t, double a, double b) {
	double tmp;
	if ((t <= -600.0) || !(t <= 1.4e+187)) {
		tmp = x * exp((-y * t));
	} else {
		tmp = x * exp(fma(-b, a, (log(z) * y)));
	}
	return tmp;
}
function code(x, y, z, t, a, b)
	tmp = 0.0
	if ((t <= -600.0) || !(t <= 1.4e+187))
		tmp = Float64(x * exp(Float64(Float64(-y) * t)));
	else
		tmp = Float64(x * exp(fma(Float64(-b), a, Float64(log(z) * y))));
	end
	return tmp
end
code[x_, y_, z_, t_, a_, b_] := If[Or[LessEqual[t, -600.0], N[Not[LessEqual[t, 1.4e+187]], $MachinePrecision]], N[(x * N[Exp[N[((-y) * t), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(x * N[Exp[N[((-b) * a + N[(N[Log[z], $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 1.4 \cdot 10^{+187}\right):\\
\;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\

\mathbf{else}:\\
\;\;\;\;x \cdot e^{\mathsf{fma}\left(-b, a, \log z \cdot y\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -600 or 1.39999999999999995e187 < t

    1. Initial program 95.9%

      \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in t around inf

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

        \[\leadsto x \cdot e^{\color{blue}{\mathsf{neg}\left(t \cdot y\right)}} \]
      2. *-commutativeN/A

        \[\leadsto x \cdot e^{\mathsf{neg}\left(\color{blue}{y \cdot t}\right)} \]
      3. distribute-lft-neg-inN/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(y\right)\right) \cdot t}} \]
      4. lower-*.f64N/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(y\right)\right) \cdot t}} \]
      5. lower-neg.f6485.0

        \[\leadsto x \cdot e^{\color{blue}{\left(-y\right)} \cdot t} \]
    5. Applied rewrites85.0%

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

    if -600 < t < 1.39999999999999995e187

    1. Initial program 93.9%

      \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in z around 0

      \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + y \cdot \left(\log z - t\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
      2. *-commutativeN/A

        \[\leadsto x \cdot e^{\left(\mathsf{neg}\left(\color{blue}{b \cdot a}\right)\right) + y \cdot \left(\log z - t\right)} \]
      3. distribute-lft-neg-inN/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) \cdot a} + y \cdot \left(\log z - t\right)} \]
      4. lower-fma.f64N/A

        \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(b\right), a, y \cdot \left(\log z - t\right)\right)}} \]
      5. lower-neg.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-b}, a, y \cdot \left(\log z - t\right)\right)} \]
      6. *-commutativeN/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
      7. lower-*.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
      8. lower--.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
      9. lower-log.f6493.9

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
    5. Applied rewrites93.9%

      \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)}} \]
    6. Taylor expanded in t around 0

      \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \log z \cdot y\right)} \]
    7. Step-by-step derivation
      1. Applied rewrites92.7%

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \log z \cdot y\right)} \]
    8. Recombined 2 regimes into one program.
    9. Final simplification89.8%

      \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 1.4 \cdot 10^{+187}\right):\\ \;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\mathsf{fma}\left(-b, a, \log z \cdot y\right)}\\ \end{array} \]
    10. Add Preprocessing

    Alternative 3: 96.8% accurate, 1.5× speedup?

    \[\begin{array}{l} \\ x \cdot e^{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)} \end{array} \]
    (FPCore (x y z t a b)
     :precision binary64
     (* x (exp (fma (- b) a (* (- (log z) t) y)))))
    double code(double x, double y, double z, double t, double a, double b) {
    	return x * exp(fma(-b, a, ((log(z) - t) * y)));
    }
    
    function code(x, y, z, t, a, b)
    	return Float64(x * exp(fma(Float64(-b), a, Float64(Float64(log(z) - t) * y))))
    end
    
    code[x_, y_, z_, t_, a_, b_] := N[(x * N[Exp[N[((-b) * a + N[(N[(N[Log[z], $MachinePrecision] - t), $MachinePrecision] * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    x \cdot e^{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)}
    \end{array}
    
    Derivation
    1. Initial program 94.7%

      \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in z around 0

      \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + y \cdot \left(\log z - t\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
      2. *-commutativeN/A

        \[\leadsto x \cdot e^{\left(\mathsf{neg}\left(\color{blue}{b \cdot a}\right)\right) + y \cdot \left(\log z - t\right)} \]
      3. distribute-lft-neg-inN/A

        \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) \cdot a} + y \cdot \left(\log z - t\right)} \]
      4. lower-fma.f64N/A

        \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(b\right), a, y \cdot \left(\log z - t\right)\right)}} \]
      5. lower-neg.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-b}, a, y \cdot \left(\log z - t\right)\right)} \]
      6. *-commutativeN/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
      7. lower-*.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
      8. lower--.f64N/A

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
      9. lower-log.f6495.1

        \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
    5. Applied rewrites95.1%

      \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)}} \]
    6. Add Preprocessing

    Alternative 4: 71.9% accurate, 2.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 3 \cdot 10^{+28}\right):\\ \;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\ \end{array} \end{array} \]
    (FPCore (x y z t a b)
     :precision binary64
     (if (or (<= t -600.0) (not (<= t 3e+28)))
       (* x (exp (* (- y) t)))
       (* x (exp (* (- b) a)))))
    double code(double x, double y, double z, double t, double a, double b) {
    	double tmp;
    	if ((t <= -600.0) || !(t <= 3e+28)) {
    		tmp = x * exp((-y * t));
    	} else {
    		tmp = x * exp((-b * a));
    	}
    	return tmp;
    }
    
    real(8) function code(x, y, z, t, a, b)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        real(8), intent (in) :: z
        real(8), intent (in) :: t
        real(8), intent (in) :: a
        real(8), intent (in) :: b
        real(8) :: tmp
        if ((t <= (-600.0d0)) .or. (.not. (t <= 3d+28))) then
            tmp = x * exp((-y * t))
        else
            tmp = x * exp((-b * a))
        end if
        code = tmp
    end function
    
    public static double code(double x, double y, double z, double t, double a, double b) {
    	double tmp;
    	if ((t <= -600.0) || !(t <= 3e+28)) {
    		tmp = x * Math.exp((-y * t));
    	} else {
    		tmp = x * Math.exp((-b * a));
    	}
    	return tmp;
    }
    
    def code(x, y, z, t, a, b):
    	tmp = 0
    	if (t <= -600.0) or not (t <= 3e+28):
    		tmp = x * math.exp((-y * t))
    	else:
    		tmp = x * math.exp((-b * a))
    	return tmp
    
    function code(x, y, z, t, a, b)
    	tmp = 0.0
    	if ((t <= -600.0) || !(t <= 3e+28))
    		tmp = Float64(x * exp(Float64(Float64(-y) * t)));
    	else
    		tmp = Float64(x * exp(Float64(Float64(-b) * a)));
    	end
    	return tmp
    end
    
    function tmp_2 = code(x, y, z, t, a, b)
    	tmp = 0.0;
    	if ((t <= -600.0) || ~((t <= 3e+28)))
    		tmp = x * exp((-y * t));
    	else
    		tmp = x * exp((-b * a));
    	end
    	tmp_2 = tmp;
    end
    
    code[x_, y_, z_, t_, a_, b_] := If[Or[LessEqual[t, -600.0], N[Not[LessEqual[t, 3e+28]], $MachinePrecision]], N[(x * N[Exp[N[((-y) * t), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(x * N[Exp[N[((-b) * a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 3 \cdot 10^{+28}\right):\\
    \;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\
    
    \mathbf{else}:\\
    \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if t < -600 or 3.0000000000000001e28 < t

      1. Initial program 96.1%

        \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
      2. Add Preprocessing
      3. Taylor expanded in t around inf

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

          \[\leadsto x \cdot e^{\color{blue}{\mathsf{neg}\left(t \cdot y\right)}} \]
        2. *-commutativeN/A

          \[\leadsto x \cdot e^{\mathsf{neg}\left(\color{blue}{y \cdot t}\right)} \]
        3. distribute-lft-neg-inN/A

          \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(y\right)\right) \cdot t}} \]
        4. lower-*.f64N/A

          \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(y\right)\right) \cdot t}} \]
        5. lower-neg.f6483.8

          \[\leadsto x \cdot e^{\color{blue}{\left(-y\right)} \cdot t} \]
      5. Applied rewrites83.8%

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

      if -600 < t < 3.0000000000000001e28

      1. Initial program 93.3%

        \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
      2. Add Preprocessing
      3. Taylor expanded in z around 0

        \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + y \cdot \left(\log z - t\right)}} \]
      4. Step-by-step derivation
        1. mul-1-negN/A

          \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
        2. *-commutativeN/A

          \[\leadsto x \cdot e^{\left(\mathsf{neg}\left(\color{blue}{b \cdot a}\right)\right) + y \cdot \left(\log z - t\right)} \]
        3. distribute-lft-neg-inN/A

          \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) \cdot a} + y \cdot \left(\log z - t\right)} \]
        4. lower-fma.f64N/A

          \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(b\right), a, y \cdot \left(\log z - t\right)\right)}} \]
        5. lower-neg.f64N/A

          \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-b}, a, y \cdot \left(\log z - t\right)\right)} \]
        6. *-commutativeN/A

          \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
        7. lower-*.f64N/A

          \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
        8. lower--.f64N/A

          \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
        9. lower-log.f6493.3

          \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
      5. Applied rewrites93.3%

        \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)}} \]
      6. Taylor expanded in y around 0

        \[\leadsto x \cdot e^{-1 \cdot \color{blue}{\left(a \cdot b\right)}} \]
      7. Step-by-step derivation
        1. Applied rewrites70.8%

          \[\leadsto x \cdot e^{\left(-b\right) \cdot \color{blue}{a}} \]
      8. Recombined 2 regimes into one program.
      9. Final simplification77.2%

        \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq -600 \lor \neg \left(t \leq 3 \cdot 10^{+28}\right):\\ \;\;\;\;x \cdot e^{\left(-y\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\ \end{array} \]
      10. Add Preprocessing

      Alternative 5: 60.2% accurate, 2.6× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -7.5 \cdot 10^{-25} \lor \neg \left(b \leq 5 \cdot 10^{-150}\right):\\ \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\left(-z\right) \cdot a}\\ \end{array} \end{array} \]
      (FPCore (x y z t a b)
       :precision binary64
       (if (or (<= b -7.5e-25) (not (<= b 5e-150)))
         (* x (exp (* (- b) a)))
         (* x (exp (* (- z) a)))))
      double code(double x, double y, double z, double t, double a, double b) {
      	double tmp;
      	if ((b <= -7.5e-25) || !(b <= 5e-150)) {
      		tmp = x * exp((-b * a));
      	} else {
      		tmp = x * exp((-z * a));
      	}
      	return tmp;
      }
      
      real(8) function code(x, y, z, t, a, b)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          real(8), intent (in) :: z
          real(8), intent (in) :: t
          real(8), intent (in) :: a
          real(8), intent (in) :: b
          real(8) :: tmp
          if ((b <= (-7.5d-25)) .or. (.not. (b <= 5d-150))) then
              tmp = x * exp((-b * a))
          else
              tmp = x * exp((-z * a))
          end if
          code = tmp
      end function
      
      public static double code(double x, double y, double z, double t, double a, double b) {
      	double tmp;
      	if ((b <= -7.5e-25) || !(b <= 5e-150)) {
      		tmp = x * Math.exp((-b * a));
      	} else {
      		tmp = x * Math.exp((-z * a));
      	}
      	return tmp;
      }
      
      def code(x, y, z, t, a, b):
      	tmp = 0
      	if (b <= -7.5e-25) or not (b <= 5e-150):
      		tmp = x * math.exp((-b * a))
      	else:
      		tmp = x * math.exp((-z * a))
      	return tmp
      
      function code(x, y, z, t, a, b)
      	tmp = 0.0
      	if ((b <= -7.5e-25) || !(b <= 5e-150))
      		tmp = Float64(x * exp(Float64(Float64(-b) * a)));
      	else
      		tmp = Float64(x * exp(Float64(Float64(-z) * a)));
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y, z, t, a, b)
      	tmp = 0.0;
      	if ((b <= -7.5e-25) || ~((b <= 5e-150)))
      		tmp = x * exp((-b * a));
      	else
      		tmp = x * exp((-z * a));
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_, z_, t_, a_, b_] := If[Or[LessEqual[b, -7.5e-25], N[Not[LessEqual[b, 5e-150]], $MachinePrecision]], N[(x * N[Exp[N[((-b) * a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(x * N[Exp[N[((-z) * a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;b \leq -7.5 \cdot 10^{-25} \lor \neg \left(b \leq 5 \cdot 10^{-150}\right):\\
      \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\
      
      \mathbf{else}:\\
      \;\;\;\;x \cdot e^{\left(-z\right) \cdot a}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if b < -7.49999999999999989e-25 or 4.9999999999999999e-150 < b

        1. Initial program 98.9%

          \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in z around 0

          \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + y \cdot \left(\log z - t\right)}} \]
        4. Step-by-step derivation
          1. mul-1-negN/A

            \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
          2. *-commutativeN/A

            \[\leadsto x \cdot e^{\left(\mathsf{neg}\left(\color{blue}{b \cdot a}\right)\right) + y \cdot \left(\log z - t\right)} \]
          3. distribute-lft-neg-inN/A

            \[\leadsto x \cdot e^{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) \cdot a} + y \cdot \left(\log z - t\right)} \]
          4. lower-fma.f64N/A

            \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(b\right), a, y \cdot \left(\log z - t\right)\right)}} \]
          5. lower-neg.f64N/A

            \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-b}, a, y \cdot \left(\log z - t\right)\right)} \]
          6. *-commutativeN/A

            \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
          7. lower-*.f64N/A

            \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
          8. lower--.f64N/A

            \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
          9. lower-log.f6499.5

            \[\leadsto x \cdot e^{\mathsf{fma}\left(-b, a, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
        5. Applied rewrites99.5%

          \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-b, a, \left(\log z - t\right) \cdot y\right)}} \]
        6. Taylor expanded in y around 0

          \[\leadsto x \cdot e^{-1 \cdot \color{blue}{\left(a \cdot b\right)}} \]
        7. Step-by-step derivation
          1. Applied rewrites71.5%

            \[\leadsto x \cdot e^{\left(-b\right) \cdot \color{blue}{a}} \]

          if -7.49999999999999989e-25 < b < 4.9999999999999999e-150

          1. Initial program 84.4%

            \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in z around 0

            \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + \left(-1 \cdot \left(a \cdot z\right) + y \cdot \left(\log z - t\right)\right)}} \]
          4. Step-by-step derivation
            1. associate-+r+N/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot b\right) + -1 \cdot \left(a \cdot z\right)\right) + y \cdot \left(\log z - t\right)}} \]
            2. +-commutativeN/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot z\right) + -1 \cdot \left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
            3. associate-*r*N/A

              \[\leadsto x \cdot e^{\left(\color{blue}{\left(-1 \cdot a\right) \cdot z} + -1 \cdot \left(a \cdot b\right)\right) + y \cdot \left(\log z - t\right)} \]
            4. associate-*r*N/A

              \[\leadsto x \cdot e^{\left(\left(-1 \cdot a\right) \cdot z + \color{blue}{\left(-1 \cdot a\right) \cdot b}\right) + y \cdot \left(\log z - t\right)} \]
            5. distribute-lft-outN/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot a\right) \cdot \left(z + b\right)} + y \cdot \left(\log z - t\right)} \]
            6. lower-fma.f64N/A

              \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-1 \cdot a, z + b, y \cdot \left(\log z - t\right)\right)}} \]
            7. mul-1-negN/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{\mathsf{neg}\left(a\right)}, z + b, y \cdot \left(\log z - t\right)\right)} \]
            8. lower-neg.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-a}, z + b, y \cdot \left(\log z - t\right)\right)} \]
            9. lower-+.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, \color{blue}{z + b}, y \cdot \left(\log z - t\right)\right)} \]
            10. *-commutativeN/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
            11. lower-*.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
            12. lower--.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
            13. lower-log.f64100.0

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
          5. Applied rewrites100.0%

            \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-a, z + b, \left(\log z - t\right) \cdot y\right)}} \]
          6. Taylor expanded in z around inf

            \[\leadsto x \cdot e^{-1 \cdot \color{blue}{\left(a \cdot z\right)}} \]
          7. Step-by-step derivation
            1. Applied rewrites53.4%

              \[\leadsto x \cdot e^{\left(-z\right) \cdot \color{blue}{a}} \]
          8. Recombined 2 regimes into one program.
          9. Final simplification66.2%

            \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -7.5 \cdot 10^{-25} \lor \neg \left(b \leq 5 \cdot 10^{-150}\right):\\ \;\;\;\;x \cdot e^{\left(-b\right) \cdot a}\\ \mathbf{else}:\\ \;\;\;\;x \cdot e^{\left(-z\right) \cdot a}\\ \end{array} \]
          10. Add Preprocessing

          Alternative 6: 33.7% accurate, 2.9× speedup?

          \[\begin{array}{l} \\ x \cdot e^{\left(-z\right) \cdot a} \end{array} \]
          (FPCore (x y z t a b) :precision binary64 (* x (exp (* (- z) a))))
          double code(double x, double y, double z, double t, double a, double b) {
          	return x * exp((-z * a));
          }
          
          real(8) function code(x, y, z, t, a, b)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              real(8), intent (in) :: z
              real(8), intent (in) :: t
              real(8), intent (in) :: a
              real(8), intent (in) :: b
              code = x * exp((-z * a))
          end function
          
          public static double code(double x, double y, double z, double t, double a, double b) {
          	return x * Math.exp((-z * a));
          }
          
          def code(x, y, z, t, a, b):
          	return x * math.exp((-z * a))
          
          function code(x, y, z, t, a, b)
          	return Float64(x * exp(Float64(Float64(-z) * a)))
          end
          
          function tmp = code(x, y, z, t, a, b)
          	tmp = x * exp((-z * a));
          end
          
          code[x_, y_, z_, t_, a_, b_] := N[(x * N[Exp[N[((-z) * a), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          x \cdot e^{\left(-z\right) \cdot a}
          \end{array}
          
          Derivation
          1. Initial program 94.7%

            \[x \cdot e^{y \cdot \left(\log z - t\right) + a \cdot \left(\log \left(1 - z\right) - b\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in z around 0

            \[\leadsto x \cdot e^{\color{blue}{-1 \cdot \left(a \cdot b\right) + \left(-1 \cdot \left(a \cdot z\right) + y \cdot \left(\log z - t\right)\right)}} \]
          4. Step-by-step derivation
            1. associate-+r+N/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot b\right) + -1 \cdot \left(a \cdot z\right)\right) + y \cdot \left(\log z - t\right)}} \]
            2. +-commutativeN/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot \left(a \cdot z\right) + -1 \cdot \left(a \cdot b\right)\right)} + y \cdot \left(\log z - t\right)} \]
            3. associate-*r*N/A

              \[\leadsto x \cdot e^{\left(\color{blue}{\left(-1 \cdot a\right) \cdot z} + -1 \cdot \left(a \cdot b\right)\right) + y \cdot \left(\log z - t\right)} \]
            4. associate-*r*N/A

              \[\leadsto x \cdot e^{\left(\left(-1 \cdot a\right) \cdot z + \color{blue}{\left(-1 \cdot a\right) \cdot b}\right) + y \cdot \left(\log z - t\right)} \]
            5. distribute-lft-outN/A

              \[\leadsto x \cdot e^{\color{blue}{\left(-1 \cdot a\right) \cdot \left(z + b\right)} + y \cdot \left(\log z - t\right)} \]
            6. lower-fma.f64N/A

              \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-1 \cdot a, z + b, y \cdot \left(\log z - t\right)\right)}} \]
            7. mul-1-negN/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{\mathsf{neg}\left(a\right)}, z + b, y \cdot \left(\log z - t\right)\right)} \]
            8. lower-neg.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(\color{blue}{-a}, z + b, y \cdot \left(\log z - t\right)\right)} \]
            9. lower-+.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, \color{blue}{z + b}, y \cdot \left(\log z - t\right)\right)} \]
            10. *-commutativeN/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
            11. lower-*.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right) \cdot y}\right)} \]
            12. lower--.f64N/A

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \color{blue}{\left(\log z - t\right)} \cdot y\right)} \]
            13. lower-log.f6499.6

              \[\leadsto x \cdot e^{\mathsf{fma}\left(-a, z + b, \left(\color{blue}{\log z} - t\right) \cdot y\right)} \]
          5. Applied rewrites99.6%

            \[\leadsto x \cdot e^{\color{blue}{\mathsf{fma}\left(-a, z + b, \left(\log z - t\right) \cdot y\right)}} \]
          6. Taylor expanded in z around inf

            \[\leadsto x \cdot e^{-1 \cdot \color{blue}{\left(a \cdot z\right)}} \]
          7. Step-by-step derivation
            1. Applied rewrites34.6%

              \[\leadsto x \cdot e^{\left(-z\right) \cdot \color{blue}{a}} \]
            2. Add Preprocessing

            Reproduce

            ?
            herbie shell --seed 2024329 
            (FPCore (x y z t a b)
              :name "Numeric.SpecFunctions:incompleteBetaApprox from math-functions-0.1.5.2, B"
              :precision binary64
              (* x (exp (+ (* y (- (log z) t)) (* a (- (log (- 1.0 z)) b))))))