System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2

Percentage Accurate: 61.6% → 95.8%
Time: 21.1s
Alternatives: 16
Speedup: 11.3×

Specification

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

\\
x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}
\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 16 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: 61.6% accurate, 1.0× speedup?

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

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

Alternative 1: 95.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := y \cdot e^{z} + \left(1 - y\right)\\ t_2 := \mathsf{expm1}\left(z\right) \cdot y\\ \mathbf{if}\;t\_1 \leq 0:\\ \;\;\;\;\mathsf{fma}\left(-x, \frac{1}{\frac{x}{\mathsf{log1p}\left(y \cdot z\right)} \cdot t}, x\right)\\ \mathbf{elif}\;t\_1 \leq 2:\\ \;\;\;\;x - \frac{t\_2}{t}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{\log t\_2}{t}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (let* ((t_1 (+ (* y (exp z)) (- 1.0 y))) (t_2 (* (expm1 z) y)))
   (if (<= t_1 0.0)
     (fma (- x) (/ 1.0 (* (/ x (log1p (* y z))) t)) x)
     (if (<= t_1 2.0) (- x (/ t_2 t)) (- x (/ (log t_2) t))))))
double code(double x, double y, double z, double t) {
	double t_1 = (y * exp(z)) + (1.0 - y);
	double t_2 = expm1(z) * y;
	double tmp;
	if (t_1 <= 0.0) {
		tmp = fma(-x, (1.0 / ((x / log1p((y * z))) * t)), x);
	} else if (t_1 <= 2.0) {
		tmp = x - (t_2 / t);
	} else {
		tmp = x - (log(t_2) / t);
	}
	return tmp;
}
function code(x, y, z, t)
	t_1 = Float64(Float64(y * exp(z)) + Float64(1.0 - y))
	t_2 = Float64(expm1(z) * y)
	tmp = 0.0
	if (t_1 <= 0.0)
		tmp = fma(Float64(-x), Float64(1.0 / Float64(Float64(x / log1p(Float64(y * z))) * t)), x);
	elseif (t_1 <= 2.0)
		tmp = Float64(x - Float64(t_2 / t));
	else
		tmp = Float64(x - Float64(log(t_2) / t));
	end
	return tmp
end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(y * N[Exp[z], $MachinePrecision]), $MachinePrecision] + N[(1.0 - y), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[(Exp[z] - 1), $MachinePrecision] * y), $MachinePrecision]}, If[LessEqual[t$95$1, 0.0], N[((-x) * N[(1.0 / N[(N[(x / N[Log[1 + N[(y * z), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * t), $MachinePrecision]), $MachinePrecision] + x), $MachinePrecision], If[LessEqual[t$95$1, 2.0], N[(x - N[(t$95$2 / t), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[t$95$2], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := y \cdot e^{z} + \left(1 - y\right)\\
t_2 := \mathsf{expm1}\left(z\right) \cdot y\\
\mathbf{if}\;t\_1 \leq 0:\\
\;\;\;\;\mathsf{fma}\left(-x, \frac{1}{\frac{x}{\mathsf{log1p}\left(y \cdot z\right)} \cdot t}, x\right)\\

\mathbf{elif}\;t\_1 \leq 2:\\
\;\;\;\;x - \frac{t\_2}{t}\\

\mathbf{else}:\\
\;\;\;\;x - \frac{\log t\_2}{t}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z))) < 0.0

    1. Initial program 1.7%

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

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

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

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

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

        \[\leadsto \color{blue}{\left(-1 \cdot x\right)} \cdot \frac{\log \left(\left(1 + y \cdot e^{z}\right) - y\right)}{t \cdot x} + x \cdot 1 \]
      5. *-rgt-identityN/A

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(-1 \cdot x, \frac{\log \left(\left(1 + y \cdot e^{z}\right) - y\right)}{t \cdot x}, x\right)} \]
    5. Applied rewrites90.3%

      \[\leadsto \color{blue}{\mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(\mathsf{expm1}\left(z\right) \cdot y\right)}{x \cdot t}, x\right)} \]
    6. Step-by-step derivation
      1. Applied rewrites90.3%

        \[\leadsto \mathsf{fma}\left(-x, \frac{1}{\color{blue}{\frac{t}{\frac{\mathsf{log1p}\left(y \cdot \mathsf{expm1}\left(z\right)\right)}{x}}}}, x\right) \]
      2. Step-by-step derivation
        1. Applied rewrites90.3%

          \[\leadsto \mathsf{fma}\left(-x, \frac{1}{\frac{x}{\mathsf{log1p}\left(\mathsf{expm1}\left(z\right) \cdot y\right)} \cdot \color{blue}{t}}, x\right) \]
        2. Taylor expanded in z around 0

          \[\leadsto \mathsf{fma}\left(\mathsf{neg}\left(x\right), \frac{1}{\frac{x}{\mathsf{log1p}\left(y \cdot z\right)} \cdot t}, x\right) \]
        3. Step-by-step derivation
          1. Applied rewrites90.3%

            \[\leadsto \mathsf{fma}\left(-x, \frac{1}{\frac{x}{\mathsf{log1p}\left(z \cdot y\right)} \cdot t}, x\right) \]

          if 0.0 < (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z))) < 2

          1. Initial program 85.4%

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

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

              \[\leadsto x - \frac{\color{blue}{\left(e^{z} - 1\right) \cdot y}}{t} \]
            2. lower-*.f64N/A

              \[\leadsto x - \frac{\color{blue}{\left(e^{z} - 1\right) \cdot y}}{t} \]
            3. lower-expm1.f6498.1

              \[\leadsto x - \frac{\color{blue}{\mathsf{expm1}\left(z\right)} \cdot y}{t} \]
          5. Applied rewrites98.1%

            \[\leadsto x - \frac{\color{blue}{\mathsf{expm1}\left(z\right) \cdot y}}{t} \]

          if 2 < (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z)))

          1. Initial program 91.9%

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

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

              \[\leadsto x - \frac{\log \color{blue}{\left(\left(e^{z} - 1\right) \cdot y\right)}}{t} \]
            2. lower-*.f64N/A

              \[\leadsto x - \frac{\log \color{blue}{\left(\left(e^{z} - 1\right) \cdot y\right)}}{t} \]
            3. lower-expm1.f6492.9

              \[\leadsto x - \frac{\log \left(\color{blue}{\mathsf{expm1}\left(z\right)} \cdot y\right)}{t} \]
          5. Applied rewrites92.9%

            \[\leadsto x - \frac{\log \color{blue}{\left(\mathsf{expm1}\left(z\right) \cdot y\right)}}{t} \]
        4. Recombined 3 regimes into one program.
        5. Final simplification95.7%

          \[\leadsto \begin{array}{l} \mathbf{if}\;y \cdot e^{z} + \left(1 - y\right) \leq 0:\\ \;\;\;\;\mathsf{fma}\left(-x, \frac{1}{\frac{x}{\mathsf{log1p}\left(y \cdot z\right)} \cdot t}, x\right)\\ \mathbf{elif}\;y \cdot e^{z} + \left(1 - y\right) \leq 2:\\ \;\;\;\;x - \frac{\mathsf{expm1}\left(z\right) \cdot y}{t}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{\log \left(\mathsf{expm1}\left(z\right) \cdot y\right)}{t}\\ \end{array} \]
        6. Add Preprocessing

        Alternative 2: 89.2% accurate, 0.6× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_1 := y \cdot e^{z} + \left(1 - y\right)\\ \mathbf{if}\;t\_1 \leq 0:\\ \;\;\;\;\mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(y \cdot z\right)}{x \cdot t}, x\right)\\ \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+27}:\\ \;\;\;\;x - \frac{\mathsf{expm1}\left(z\right) \cdot y}{t}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{\log 1}{t}\\ \end{array} \end{array} \]
        (FPCore (x y z t)
         :precision binary64
         (let* ((t_1 (+ (* y (exp z)) (- 1.0 y))))
           (if (<= t_1 0.0)
             (fma (- x) (/ (log1p (* y z)) (* x t)) x)
             (if (<= t_1 5e+27) (- x (/ (* (expm1 z) y) t)) (- x (/ (log 1.0) t))))))
        double code(double x, double y, double z, double t) {
        	double t_1 = (y * exp(z)) + (1.0 - y);
        	double tmp;
        	if (t_1 <= 0.0) {
        		tmp = fma(-x, (log1p((y * z)) / (x * t)), x);
        	} else if (t_1 <= 5e+27) {
        		tmp = x - ((expm1(z) * y) / t);
        	} else {
        		tmp = x - (log(1.0) / t);
        	}
        	return tmp;
        }
        
        function code(x, y, z, t)
        	t_1 = Float64(Float64(y * exp(z)) + Float64(1.0 - y))
        	tmp = 0.0
        	if (t_1 <= 0.0)
        		tmp = fma(Float64(-x), Float64(log1p(Float64(y * z)) / Float64(x * t)), x);
        	elseif (t_1 <= 5e+27)
        		tmp = Float64(x - Float64(Float64(expm1(z) * y) / t));
        	else
        		tmp = Float64(x - Float64(log(1.0) / t));
        	end
        	return tmp
        end
        
        code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(y * N[Exp[z], $MachinePrecision]), $MachinePrecision] + N[(1.0 - y), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$1, 0.0], N[((-x) * N[(N[Log[1 + N[(y * z), $MachinePrecision]], $MachinePrecision] / N[(x * t), $MachinePrecision]), $MachinePrecision] + x), $MachinePrecision], If[LessEqual[t$95$1, 5e+27], N[(x - N[(N[(N[(Exp[z] - 1), $MachinePrecision] * y), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[1.0], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_1 := y \cdot e^{z} + \left(1 - y\right)\\
        \mathbf{if}\;t\_1 \leq 0:\\
        \;\;\;\;\mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(y \cdot z\right)}{x \cdot t}, x\right)\\
        
        \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+27}:\\
        \;\;\;\;x - \frac{\mathsf{expm1}\left(z\right) \cdot y}{t}\\
        
        \mathbf{else}:\\
        \;\;\;\;x - \frac{\log 1}{t}\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 3 regimes
        2. if (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z))) < 0.0

          1. Initial program 2.1%

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

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

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

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

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

              \[\leadsto \color{blue}{\left(-1 \cdot x\right)} \cdot \frac{\log \left(\left(1 + y \cdot e^{z}\right) - y\right)}{t \cdot x} + x \cdot 1 \]
            5. *-rgt-identityN/A

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

              \[\leadsto \color{blue}{\mathsf{fma}\left(-1 \cdot x, \frac{\log \left(\left(1 + y \cdot e^{z}\right) - y\right)}{t \cdot x}, x\right)} \]
          5. Applied rewrites88.0%

            \[\leadsto \color{blue}{\mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(\mathsf{expm1}\left(z\right) \cdot y\right)}{x \cdot t}, x\right)} \]
          6. Taylor expanded in z around 0

            \[\leadsto \mathsf{fma}\left(\mathsf{neg}\left(x\right), \frac{\mathsf{log1p}\left(y \cdot z\right)}{x \cdot t}, x\right) \]
          7. Step-by-step derivation
            1. Applied rewrites88.0%

              \[\leadsto \mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(z \cdot y\right)}{x \cdot t}, x\right) \]

            if 0.0 < (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z))) < 4.99999999999999979e27

            1. Initial program 81.1%

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

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

                \[\leadsto x - \frac{\color{blue}{\left(e^{z} - 1\right) \cdot y}}{t} \]
              2. lower-*.f64N/A

                \[\leadsto x - \frac{\color{blue}{\left(e^{z} - 1\right) \cdot y}}{t} \]
              3. lower-expm1.f6496.9

                \[\leadsto x - \frac{\color{blue}{\mathsf{expm1}\left(z\right)} \cdot y}{t} \]
            5. Applied rewrites96.9%

              \[\leadsto x - \frac{\color{blue}{\mathsf{expm1}\left(z\right) \cdot y}}{t} \]

            if 4.99999999999999979e27 < (+.f64 (-.f64 #s(literal 1 binary64) y) (*.f64 y (exp.f64 z)))

            1. Initial program 94.9%

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

              \[\leadsto x - \frac{\log \color{blue}{1}}{t} \]
            4. Step-by-step derivation
              1. Applied rewrites47.8%

                \[\leadsto x - \frac{\log \color{blue}{1}}{t} \]
            5. Recombined 3 regimes into one program.
            6. Final simplification89.2%

              \[\leadsto \begin{array}{l} \mathbf{if}\;y \cdot e^{z} + \left(1 - y\right) \leq 0:\\ \;\;\;\;\mathsf{fma}\left(-x, \frac{\mathsf{log1p}\left(y \cdot z\right)}{x \cdot t}, x\right)\\ \mathbf{elif}\;y \cdot e^{z} + \left(1 - y\right) \leq 5 \cdot 10^{+27}:\\ \;\;\;\;x - \frac{\mathsf{expm1}\left(z\right) \cdot y}{t}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{\log 1}{t}\\ \end{array} \]
            7. Add Preprocessing

            Developer Target 1: 74.2% accurate, 1.8× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{-0.5}{y \cdot t}\\ \mathbf{if}\;z < -2.8874623088207947 \cdot 10^{+119}:\\ \;\;\;\;\left(x - \frac{t\_1}{z \cdot z}\right) - t\_1 \cdot \frac{\frac{2}{z}}{z \cdot z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{\log \left(1 + z \cdot y\right)}{t}\\ \end{array} \end{array} \]
            (FPCore (x y z t)
             :precision binary64
             (let* ((t_1 (/ (- 0.5) (* y t))))
               (if (< z -2.8874623088207947e+119)
                 (- (- x (/ t_1 (* z z))) (* t_1 (/ (/ 2.0 z) (* z z))))
                 (- x (/ (log (+ 1.0 (* z y))) t)))))
            double code(double x, double y, double z, double t) {
            	double t_1 = -0.5 / (y * t);
            	double tmp;
            	if (z < -2.8874623088207947e+119) {
            		tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)));
            	} else {
            		tmp = x - (log((1.0 + (z * y))) / t);
            	}
            	return tmp;
            }
            
            real(8) function code(x, y, z, t)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                real(8), intent (in) :: z
                real(8), intent (in) :: t
                real(8) :: t_1
                real(8) :: tmp
                t_1 = -0.5d0 / (y * t)
                if (z < (-2.8874623088207947d+119)) then
                    tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0d0 / z) / (z * z)))
                else
                    tmp = x - (log((1.0d0 + (z * y))) / t)
                end if
                code = tmp
            end function
            
            public static double code(double x, double y, double z, double t) {
            	double t_1 = -0.5 / (y * t);
            	double tmp;
            	if (z < -2.8874623088207947e+119) {
            		tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)));
            	} else {
            		tmp = x - (Math.log((1.0 + (z * y))) / t);
            	}
            	return tmp;
            }
            
            def code(x, y, z, t):
            	t_1 = -0.5 / (y * t)
            	tmp = 0
            	if z < -2.8874623088207947e+119:
            		tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)))
            	else:
            		tmp = x - (math.log((1.0 + (z * y))) / t)
            	return tmp
            
            function code(x, y, z, t)
            	t_1 = Float64(Float64(-0.5) / Float64(y * t))
            	tmp = 0.0
            	if (z < -2.8874623088207947e+119)
            		tmp = Float64(Float64(x - Float64(t_1 / Float64(z * z))) - Float64(t_1 * Float64(Float64(2.0 / z) / Float64(z * z))));
            	else
            		tmp = Float64(x - Float64(log(Float64(1.0 + Float64(z * y))) / t));
            	end
            	return tmp
            end
            
            function tmp_2 = code(x, y, z, t)
            	t_1 = -0.5 / (y * t);
            	tmp = 0.0;
            	if (z < -2.8874623088207947e+119)
            		tmp = (x - (t_1 / (z * z))) - (t_1 * ((2.0 / z) / (z * z)));
            	else
            		tmp = x - (log((1.0 + (z * y))) / t);
            	end
            	tmp_2 = tmp;
            end
            
            code[x_, y_, z_, t_] := Block[{t$95$1 = N[((-0.5) / N[(y * t), $MachinePrecision]), $MachinePrecision]}, If[Less[z, -2.8874623088207947e+119], N[(N[(x - N[(t$95$1 / N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(t$95$1 * N[(N[(2.0 / z), $MachinePrecision] / N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[Log[N[(1.0 + N[(z * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]
            
            \begin{array}{l}
            
            \\
            \begin{array}{l}
            t_1 := \frac{-0.5}{y \cdot t}\\
            \mathbf{if}\;z < -2.8874623088207947 \cdot 10^{+119}:\\
            \;\;\;\;\left(x - \frac{t\_1}{z \cdot z}\right) - t\_1 \cdot \frac{\frac{2}{z}}{z \cdot z}\\
            
            \mathbf{else}:\\
            \;\;\;\;x - \frac{\log \left(1 + z \cdot y\right)}{t}\\
            
            
            \end{array}
            \end{array}
            

            Reproduce

            ?
            herbie shell --seed 2024230 
            (FPCore (x y z t)
              :name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"
              :precision binary64
            
              :alt
              (! :herbie-platform default (if (< z -288746230882079470000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (- (- x (/ (/ (- 1/2) (* y t)) (* z z))) (* (/ (- 1/2) (* y t)) (/ (/ 2 z) (* z z)))) (- x (/ (log (+ 1 (* z y))) t))))
            
              (- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))