Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2

Percentage Accurate: 99.8% → 99.9%
Time: 7.5s
Alternatives: 10
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \end{array} \]
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * log(y))) + y) - z;
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = ((x - ((y + 0.5d0) * log(y))) + y) - z
end function
public static double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * Math.log(y))) + y) - z;
}
def code(x, y, z):
	return ((x - ((y + 0.5) * math.log(y))) + y) - z
function code(x, y, z)
	return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z)
end
function tmp = code(x, y, z)
	tmp = ((x - ((y + 0.5) * log(y))) + y) - z;
end
code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z
\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 10 alternatives:

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

Initial Program: 99.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \end{array} \]
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * log(y))) + y) - z;
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = ((x - ((y + 0.5d0) * log(y))) + y) - z
end function
public static double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * Math.log(y))) + y) - z;
}
def code(x, y, z):
	return ((x - ((y + 0.5) * math.log(y))) + y) - z
function code(x, y, z)
	return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z)
end
function tmp = code(x, y, z)
	tmp = ((x - ((y + 0.5) * log(y))) + y) - z;
end
code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z
\end{array}

Alternative 1: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\mathsf{fma}\left(-0.5 - y, \log y, y\right) + x\right) - z \end{array} \]
(FPCore (x y z) :precision binary64 (- (+ (fma (- -0.5 y) (log y) y) x) z))
double code(double x, double y, double z) {
	return (fma((-0.5 - y), log(y), y) + x) - z;
}
function code(x, y, z)
	return Float64(Float64(fma(Float64(-0.5 - y), log(y), y) + x) - z)
end
code[x_, y_, z_] := N[(N[(N[(N[(-0.5 - y), $MachinePrecision] * N[Log[y], $MachinePrecision] + y), $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}

\\
\left(\mathsf{fma}\left(-0.5 - y, \log y, y\right) + x\right) - z
\end{array}
Derivation
  1. Initial program 99.8%

    \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-+.f64N/A

      \[\leadsto \color{blue}{\left(\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right) + y\right)} - z \]
    2. lift--.f64N/A

      \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
    3. sub-negN/A

      \[\leadsto \left(\color{blue}{\left(x + \left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right)\right)} + y\right) - z \]
    4. associate-+l+N/A

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

      \[\leadsto \color{blue}{\left(x + \left(\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + y\right)\right)} - z \]
    6. lift-*.f64N/A

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

      \[\leadsto \left(x + \left(\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + y\right)\right) - z \]
    8. lower-fma.f64N/A

      \[\leadsto \left(x + \color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, y\right)}\right) - z \]
    9. lift-+.f64N/A

      \[\leadsto \left(x + \mathsf{fma}\left(\mathsf{neg}\left(\color{blue}{\left(y + \frac{1}{2}\right)}\right), \log y, y\right)\right) - z \]
    10. +-commutativeN/A

      \[\leadsto \left(x + \mathsf{fma}\left(\mathsf{neg}\left(\color{blue}{\left(\frac{1}{2} + y\right)}\right), \log y, y\right)\right) - z \]
    11. distribute-neg-inN/A

      \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) + \left(\mathsf{neg}\left(y\right)\right)}, \log y, y\right)\right) - z \]
    12. unsub-negN/A

      \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) - y}, \log y, y\right)\right) - z \]
    13. lower--.f64N/A

      \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) - y}, \log y, y\right)\right) - z \]
    14. metadata-eval99.9

      \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{-0.5} - y, \log y, y\right)\right) - z \]
  4. Applied rewrites99.9%

    \[\leadsto \color{blue}{\left(x + \mathsf{fma}\left(-0.5 - y, \log y, y\right)\right)} - z \]
  5. Final simplification99.9%

    \[\leadsto \left(\mathsf{fma}\left(-0.5 - y, \log y, y\right) + x\right) - z \]
  6. Add Preprocessing

Alternative 2: 68.5% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\ t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\ \mathbf{if}\;t\_1 \leq -5 \cdot 10^{+147}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_1 \leq -200:\\ \;\;\;\;\left(1 - \log y\right) \cdot y\\ \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+15}:\\ \;\;\;\;y - \mathsf{fma}\left(0.5, \log y, z\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (let* ((t_0 (- (+ (/ 1.0 (/ 1.0 x)) y) z))
        (t_1 (- (+ (- x (* (+ 0.5 y) (log y))) y) z)))
   (if (<= t_1 -5e+147)
     t_0
     (if (<= t_1 -200.0)
       (* (- 1.0 (log y)) y)
       (if (<= t_1 5e+15) (- y (fma 0.5 (log y) z)) t_0)))))
double code(double x, double y, double z) {
	double t_0 = ((1.0 / (1.0 / x)) + y) - z;
	double t_1 = ((x - ((0.5 + y) * log(y))) + y) - z;
	double tmp;
	if (t_1 <= -5e+147) {
		tmp = t_0;
	} else if (t_1 <= -200.0) {
		tmp = (1.0 - log(y)) * y;
	} else if (t_1 <= 5e+15) {
		tmp = y - fma(0.5, log(y), z);
	} else {
		tmp = t_0;
	}
	return tmp;
}
function code(x, y, z)
	t_0 = Float64(Float64(Float64(1.0 / Float64(1.0 / x)) + y) - z)
	t_1 = Float64(Float64(Float64(x - Float64(Float64(0.5 + y) * log(y))) + y) - z)
	tmp = 0.0
	if (t_1 <= -5e+147)
		tmp = t_0;
	elseif (t_1 <= -200.0)
		tmp = Float64(Float64(1.0 - log(y)) * y);
	elseif (t_1 <= 5e+15)
		tmp = Float64(y - fma(0.5, log(y), z));
	else
		tmp = t_0;
	end
	return tmp
end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(N[(1.0 / N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(x - N[(N[(0.5 + y), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[t$95$1, -5e+147], t$95$0, If[LessEqual[t$95$1, -200.0], N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision], If[LessEqual[t$95$1, 5e+15], N[(y - N[(0.5 * N[Log[y], $MachinePrecision] + z), $MachinePrecision]), $MachinePrecision], t$95$0]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\
t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\
\mathbf{if}\;t\_1 \leq -5 \cdot 10^{+147}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;t\_1 \leq -200:\\
\;\;\;\;\left(1 - \log y\right) \cdot y\\

\mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+15}:\\
\;\;\;\;y - \mathsf{fma}\left(0.5, \log y, z\right)\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < -5.0000000000000002e147 or 5e15 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z)

    1. Initial program 99.9%

      \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
      2. flip--N/A

        \[\leadsto \left(\color{blue}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}} + y\right) - z \]
      3. clear-numN/A

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

        \[\leadsto \left(\color{blue}{\frac{1}{\frac{x + \left(y + \frac{1}{2}\right) \cdot \log y}{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}}} + y\right) - z \]
      5. clear-numN/A

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}}}} + y\right) - z \]
      6. flip--N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
      7. lift--.f64N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
      8. lower-/.f6499.8

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x - \left(y + 0.5\right) \cdot \log y}}} + y\right) - z \]
      9. lift--.f64N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
      10. sub-negN/A

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

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + x}}} + y\right) - z \]
      12. lift-*.f64N/A

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

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + x}} + y\right) - z \]
      14. lower-fma.f64N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, x\right)}}} + y\right) - z \]
    4. Applied rewrites99.8%

      \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{\mathsf{fma}\left(-0.5 - y, \log y, x\right)}}} + y\right) - z \]
    5. Taylor expanded in x around inf

      \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
    6. Step-by-step derivation
      1. lower-/.f6476.4

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
    7. Applied rewrites76.4%

      \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]

    if -5.0000000000000002e147 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < -200

    1. Initial program 99.7%

      \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
    2. Add Preprocessing
    3. Taylor expanded in y around inf

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

        \[\leadsto \color{blue}{\left(1 - -1 \cdot \log \left(\frac{1}{y}\right)\right) \cdot y} \]
      2. mul-1-negN/A

        \[\leadsto \left(1 - \color{blue}{\left(\mathsf{neg}\left(\log \left(\frac{1}{y}\right)\right)\right)}\right) \cdot y \]
      3. log-recN/A

        \[\leadsto \left(1 - \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(\log y\right)\right)}\right)\right)\right) \cdot y \]
      4. remove-double-negN/A

        \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
      5. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]
      6. lower--.f64N/A

        \[\leadsto \color{blue}{\left(1 - \log y\right)} \cdot y \]
      7. lower-log.f6461.4

        \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
    5. Applied rewrites61.4%

      \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]

    if -200 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < 5e15

    1. Initial program 99.9%

      \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{y - \left(z + \log y \cdot \left(\frac{1}{2} + y\right)\right)} \]
    4. Step-by-step derivation
      1. lower--.f64N/A

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

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

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

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

        \[\leadsto y - \mathsf{fma}\left(\color{blue}{\frac{1}{2} + y}, \log y, z\right) \]
      6. lower-log.f6491.1

        \[\leadsto y - \mathsf{fma}\left(0.5 + y, \color{blue}{\log y}, z\right) \]
    5. Applied rewrites91.1%

      \[\leadsto \color{blue}{y - \mathsf{fma}\left(0.5 + y, \log y, z\right)} \]
    6. Taylor expanded in y around 0

      \[\leadsto y - \mathsf{fma}\left(\frac{1}{2}, \log \color{blue}{y}, z\right) \]
    7. Step-by-step derivation
      1. Applied rewrites90.4%

        \[\leadsto y - \mathsf{fma}\left(0.5, \log \color{blue}{y}, z\right) \]
    8. Recombined 3 regimes into one program.
    9. Final simplification75.7%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq -5 \cdot 10^{+147}:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \mathbf{elif}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq -200:\\ \;\;\;\;\left(1 - \log y\right) \cdot y\\ \mathbf{elif}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq 5 \cdot 10^{+15}:\\ \;\;\;\;y - \mathsf{fma}\left(0.5, \log y, z\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \end{array} \]
    10. Add Preprocessing

    Alternative 3: 68.5% accurate, 0.2× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\ t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\ \mathbf{if}\;t\_1 \leq -5 \cdot 10^{+147}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_1 \leq -200:\\ \;\;\;\;\left(1 - \log y\right) \cdot y\\ \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+15}:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, -z\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
    (FPCore (x y z)
     :precision binary64
     (let* ((t_0 (- (+ (/ 1.0 (/ 1.0 x)) y) z))
            (t_1 (- (+ (- x (* (+ 0.5 y) (log y))) y) z)))
       (if (<= t_1 -5e+147)
         t_0
         (if (<= t_1 -200.0)
           (* (- 1.0 (log y)) y)
           (if (<= t_1 5e+15) (fma -0.5 (log y) (- z)) t_0)))))
    double code(double x, double y, double z) {
    	double t_0 = ((1.0 / (1.0 / x)) + y) - z;
    	double t_1 = ((x - ((0.5 + y) * log(y))) + y) - z;
    	double tmp;
    	if (t_1 <= -5e+147) {
    		tmp = t_0;
    	} else if (t_1 <= -200.0) {
    		tmp = (1.0 - log(y)) * y;
    	} else if (t_1 <= 5e+15) {
    		tmp = fma(-0.5, log(y), -z);
    	} else {
    		tmp = t_0;
    	}
    	return tmp;
    }
    
    function code(x, y, z)
    	t_0 = Float64(Float64(Float64(1.0 / Float64(1.0 / x)) + y) - z)
    	t_1 = Float64(Float64(Float64(x - Float64(Float64(0.5 + y) * log(y))) + y) - z)
    	tmp = 0.0
    	if (t_1 <= -5e+147)
    		tmp = t_0;
    	elseif (t_1 <= -200.0)
    		tmp = Float64(Float64(1.0 - log(y)) * y);
    	elseif (t_1 <= 5e+15)
    		tmp = fma(-0.5, log(y), Float64(-z));
    	else
    		tmp = t_0;
    	end
    	return tmp
    end
    
    code[x_, y_, z_] := Block[{t$95$0 = N[(N[(N[(1.0 / N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(x - N[(N[(0.5 + y), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[t$95$1, -5e+147], t$95$0, If[LessEqual[t$95$1, -200.0], N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision], If[LessEqual[t$95$1, 5e+15], N[(-0.5 * N[Log[y], $MachinePrecision] + (-z)), $MachinePrecision], t$95$0]]]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\
    t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\
    \mathbf{if}\;t\_1 \leq -5 \cdot 10^{+147}:\\
    \;\;\;\;t\_0\\
    
    \mathbf{elif}\;t\_1 \leq -200:\\
    \;\;\;\;\left(1 - \log y\right) \cdot y\\
    
    \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+15}:\\
    \;\;\;\;\mathsf{fma}\left(-0.5, \log y, -z\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_0\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < -5.0000000000000002e147 or 5e15 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z)

      1. Initial program 99.9%

        \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift--.f64N/A

          \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
        2. flip--N/A

          \[\leadsto \left(\color{blue}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}} + y\right) - z \]
        3. clear-numN/A

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

          \[\leadsto \left(\color{blue}{\frac{1}{\frac{x + \left(y + \frac{1}{2}\right) \cdot \log y}{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}}} + y\right) - z \]
        5. clear-numN/A

          \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}}}} + y\right) - z \]
        6. flip--N/A

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
        7. lift--.f64N/A

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
        8. lower-/.f6499.8

          \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x - \left(y + 0.5\right) \cdot \log y}}} + y\right) - z \]
        9. lift--.f64N/A

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
        10. sub-negN/A

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

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + x}}} + y\right) - z \]
        12. lift-*.f64N/A

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

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + x}} + y\right) - z \]
        14. lower-fma.f64N/A

          \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, x\right)}}} + y\right) - z \]
      4. Applied rewrites99.8%

        \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{\mathsf{fma}\left(-0.5 - y, \log y, x\right)}}} + y\right) - z \]
      5. Taylor expanded in x around inf

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
      6. Step-by-step derivation
        1. lower-/.f6476.4

          \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
      7. Applied rewrites76.4%

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]

      if -5.0000000000000002e147 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < -200

      1. Initial program 99.7%

        \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
      2. Add Preprocessing
      3. Taylor expanded in y around inf

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

          \[\leadsto \color{blue}{\left(1 - -1 \cdot \log \left(\frac{1}{y}\right)\right) \cdot y} \]
        2. mul-1-negN/A

          \[\leadsto \left(1 - \color{blue}{\left(\mathsf{neg}\left(\log \left(\frac{1}{y}\right)\right)\right)}\right) \cdot y \]
        3. log-recN/A

          \[\leadsto \left(1 - \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(\log y\right)\right)}\right)\right)\right) \cdot y \]
        4. remove-double-negN/A

          \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
        5. lower-*.f64N/A

          \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]
        6. lower--.f64N/A

          \[\leadsto \color{blue}{\left(1 - \log y\right)} \cdot y \]
        7. lower-log.f6461.4

          \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
      5. Applied rewrites61.4%

        \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]

      if -200 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < 5e15

      1. Initial program 99.9%

        \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \color{blue}{y - \left(z + \log y \cdot \left(\frac{1}{2} + y\right)\right)} \]
      4. Step-by-step derivation
        1. lower--.f64N/A

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

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

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

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

          \[\leadsto y - \mathsf{fma}\left(\color{blue}{\frac{1}{2} + y}, \log y, z\right) \]
        6. lower-log.f6491.1

          \[\leadsto y - \mathsf{fma}\left(0.5 + y, \color{blue}{\log y}, z\right) \]
      5. Applied rewrites91.1%

        \[\leadsto \color{blue}{y - \mathsf{fma}\left(0.5 + y, \log y, z\right)} \]
      6. Taylor expanded in y around 0

        \[\leadsto -1 \cdot \color{blue}{\left(z + \frac{1}{2} \cdot \log y\right)} \]
      7. Step-by-step derivation
        1. Applied rewrites90.4%

          \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\log y}, -z\right) \]
      8. Recombined 3 regimes into one program.
      9. Final simplification75.7%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq -5 \cdot 10^{+147}:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \mathbf{elif}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq -200:\\ \;\;\;\;\left(1 - \log y\right) \cdot y\\ \mathbf{elif}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq 5 \cdot 10^{+15}:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, -z\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \end{array} \]
      10. Add Preprocessing

      Alternative 4: 68.4% accurate, 0.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\ t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\ \mathbf{if}\;t\_1 \leq -40000000000000:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_1 \leq 500:\\ \;\;\;\;\log y \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
      (FPCore (x y z)
       :precision binary64
       (let* ((t_0 (- (+ (/ 1.0 (/ 1.0 x)) y) z))
              (t_1 (- (+ (- x (* (+ 0.5 y) (log y))) y) z)))
         (if (<= t_1 -40000000000000.0)
           t_0
           (if (<= t_1 500.0) (* (log y) -0.5) t_0))))
      double code(double x, double y, double z) {
      	double t_0 = ((1.0 / (1.0 / x)) + y) - z;
      	double t_1 = ((x - ((0.5 + y) * log(y))) + y) - z;
      	double tmp;
      	if (t_1 <= -40000000000000.0) {
      		tmp = t_0;
      	} else if (t_1 <= 500.0) {
      		tmp = log(y) * -0.5;
      	} else {
      		tmp = t_0;
      	}
      	return tmp;
      }
      
      real(8) function code(x, y, z)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          real(8), intent (in) :: z
          real(8) :: t_0
          real(8) :: t_1
          real(8) :: tmp
          t_0 = ((1.0d0 / (1.0d0 / x)) + y) - z
          t_1 = ((x - ((0.5d0 + y) * log(y))) + y) - z
          if (t_1 <= (-40000000000000.0d0)) then
              tmp = t_0
          else if (t_1 <= 500.0d0) then
              tmp = log(y) * (-0.5d0)
          else
              tmp = t_0
          end if
          code = tmp
      end function
      
      public static double code(double x, double y, double z) {
      	double t_0 = ((1.0 / (1.0 / x)) + y) - z;
      	double t_1 = ((x - ((0.5 + y) * Math.log(y))) + y) - z;
      	double tmp;
      	if (t_1 <= -40000000000000.0) {
      		tmp = t_0;
      	} else if (t_1 <= 500.0) {
      		tmp = Math.log(y) * -0.5;
      	} else {
      		tmp = t_0;
      	}
      	return tmp;
      }
      
      def code(x, y, z):
      	t_0 = ((1.0 / (1.0 / x)) + y) - z
      	t_1 = ((x - ((0.5 + y) * math.log(y))) + y) - z
      	tmp = 0
      	if t_1 <= -40000000000000.0:
      		tmp = t_0
      	elif t_1 <= 500.0:
      		tmp = math.log(y) * -0.5
      	else:
      		tmp = t_0
      	return tmp
      
      function code(x, y, z)
      	t_0 = Float64(Float64(Float64(1.0 / Float64(1.0 / x)) + y) - z)
      	t_1 = Float64(Float64(Float64(x - Float64(Float64(0.5 + y) * log(y))) + y) - z)
      	tmp = 0.0
      	if (t_1 <= -40000000000000.0)
      		tmp = t_0;
      	elseif (t_1 <= 500.0)
      		tmp = Float64(log(y) * -0.5);
      	else
      		tmp = t_0;
      	end
      	return tmp
      end
      
      function tmp_2 = code(x, y, z)
      	t_0 = ((1.0 / (1.0 / x)) + y) - z;
      	t_1 = ((x - ((0.5 + y) * log(y))) + y) - z;
      	tmp = 0.0;
      	if (t_1 <= -40000000000000.0)
      		tmp = t_0;
      	elseif (t_1 <= 500.0)
      		tmp = log(y) * -0.5;
      	else
      		tmp = t_0;
      	end
      	tmp_2 = tmp;
      end
      
      code[x_, y_, z_] := Block[{t$95$0 = N[(N[(N[(1.0 / N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(x - N[(N[(0.5 + y), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[t$95$1, -40000000000000.0], t$95$0, If[LessEqual[t$95$1, 500.0], N[(N[Log[y], $MachinePrecision] * -0.5), $MachinePrecision], t$95$0]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\
      t_1 := \left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z\\
      \mathbf{if}\;t\_1 \leq -40000000000000:\\
      \;\;\;\;t\_0\\
      
      \mathbf{elif}\;t\_1 \leq 500:\\
      \;\;\;\;\log y \cdot -0.5\\
      
      \mathbf{else}:\\
      \;\;\;\;t\_0\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < -4e13 or 500 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z)

        1. Initial program 99.8%

          \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift--.f64N/A

            \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
          2. flip--N/A

            \[\leadsto \left(\color{blue}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}} + y\right) - z \]
          3. clear-numN/A

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

            \[\leadsto \left(\color{blue}{\frac{1}{\frac{x + \left(y + \frac{1}{2}\right) \cdot \log y}{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}}} + y\right) - z \]
          5. clear-numN/A

            \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}}}} + y\right) - z \]
          6. flip--N/A

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
          7. lift--.f64N/A

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
          8. lower-/.f6499.7

            \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x - \left(y + 0.5\right) \cdot \log y}}} + y\right) - z \]
          9. lift--.f64N/A

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
          10. sub-negN/A

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

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + x}}} + y\right) - z \]
          12. lift-*.f64N/A

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

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + x}} + y\right) - z \]
          14. lower-fma.f64N/A

            \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, x\right)}}} + y\right) - z \]
        4. Applied rewrites99.7%

          \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{\mathsf{fma}\left(-0.5 - y, \log y, x\right)}}} + y\right) - z \]
        5. Taylor expanded in x around inf

          \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
        6. Step-by-step derivation
          1. lower-/.f6469.5

            \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
        7. Applied rewrites69.5%

          \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]

        if -4e13 < (-.f64 (+.f64 (-.f64 x (*.f64 (+.f64 y #s(literal 1/2 binary64)) (log.f64 y))) y) z) < 500

        1. Initial program 99.9%

          \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{y - \left(z + \log y \cdot \left(\frac{1}{2} + y\right)\right)} \]
        4. Step-by-step derivation
          1. lower--.f64N/A

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

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

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

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

            \[\leadsto y - \mathsf{fma}\left(\color{blue}{\frac{1}{2} + y}, \log y, z\right) \]
          6. lower-log.f6490.7

            \[\leadsto y - \mathsf{fma}\left(0.5 + y, \color{blue}{\log y}, z\right) \]
        5. Applied rewrites90.7%

          \[\leadsto \color{blue}{y - \mathsf{fma}\left(0.5 + y, \log y, z\right)} \]
        6. Taylor expanded in y around 0

          \[\leadsto -1 \cdot \color{blue}{\left(z + \frac{1}{2} \cdot \log y\right)} \]
        7. Step-by-step derivation
          1. Applied rewrites84.5%

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

            \[\leadsto \frac{-1}{2} \cdot \log y \]
          3. Step-by-step derivation
            1. Applied rewrites84.5%

              \[\leadsto \log y \cdot -0.5 \]
          4. Recombined 2 regimes into one program.
          5. Final simplification71.4%

            \[\leadsto \begin{array}{l} \mathbf{if}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq -40000000000000:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \mathbf{elif}\;\left(\left(x - \left(0.5 + y\right) \cdot \log y\right) + y\right) - z \leq 500:\\ \;\;\;\;\log y \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \end{array} \]
          6. Add Preprocessing

          Alternative 5: 89.2% accurate, 0.9× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \mathsf{fma}\left(-0.5, \log y, x\right) - z\\ \mathbf{if}\;x \leq -3.6 \cdot 10^{+41}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;x \leq 4 \cdot 10^{+54}:\\ \;\;\;\;y - \mathsf{fma}\left(0.5 + y, \log y, z\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
          (FPCore (x y z)
           :precision binary64
           (let* ((t_0 (- (fma -0.5 (log y) x) z)))
             (if (<= x -3.6e+41)
               t_0
               (if (<= x 4e+54) (- y (fma (+ 0.5 y) (log y) z)) t_0))))
          double code(double x, double y, double z) {
          	double t_0 = fma(-0.5, log(y), x) - z;
          	double tmp;
          	if (x <= -3.6e+41) {
          		tmp = t_0;
          	} else if (x <= 4e+54) {
          		tmp = y - fma((0.5 + y), log(y), z);
          	} else {
          		tmp = t_0;
          	}
          	return tmp;
          }
          
          function code(x, y, z)
          	t_0 = Float64(fma(-0.5, log(y), x) - z)
          	tmp = 0.0
          	if (x <= -3.6e+41)
          		tmp = t_0;
          	elseif (x <= 4e+54)
          		tmp = Float64(y - fma(Float64(0.5 + y), log(y), z));
          	else
          		tmp = t_0;
          	end
          	return tmp
          end
          
          code[x_, y_, z_] := Block[{t$95$0 = N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[x, -3.6e+41], t$95$0, If[LessEqual[x, 4e+54], N[(y - N[(N[(0.5 + y), $MachinePrecision] * N[Log[y], $MachinePrecision] + z), $MachinePrecision]), $MachinePrecision], t$95$0]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \mathsf{fma}\left(-0.5, \log y, x\right) - z\\
          \mathbf{if}\;x \leq -3.6 \cdot 10^{+41}:\\
          \;\;\;\;t\_0\\
          
          \mathbf{elif}\;x \leq 4 \cdot 10^{+54}:\\
          \;\;\;\;y - \mathsf{fma}\left(0.5 + y, \log y, z\right)\\
          
          \mathbf{else}:\\
          \;\;\;\;t\_0\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if x < -3.60000000000000025e41 or 4.0000000000000003e54 < x

            1. Initial program 99.9%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Taylor expanded in y around 0

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

                \[\leadsto x - \color{blue}{\left(\frac{1}{2} \cdot \log y + z\right)} \]
              2. associate--r+N/A

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

                \[\leadsto \color{blue}{\left(x - \frac{1}{2} \cdot \log y\right) - z} \]
              4. sub-negN/A

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

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

                \[\leadsto \left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) \cdot \log y} + x\right) - z \]
              7. metadata-evalN/A

                \[\leadsto \left(\color{blue}{\frac{-1}{2}} \cdot \log y + x\right) - z \]
              8. lower-fma.f64N/A

                \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{-1}{2}, \log y, x\right)} - z \]
              9. lower-log.f6488.2

                \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\log y}, x\right) - z \]
            5. Applied rewrites88.2%

              \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, \log y, x\right) - z} \]

            if -3.60000000000000025e41 < x < 4.0000000000000003e54

            1. Initial program 99.8%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Taylor expanded in x around 0

              \[\leadsto \color{blue}{y - \left(z + \log y \cdot \left(\frac{1}{2} + y\right)\right)} \]
            4. Step-by-step derivation
              1. lower--.f64N/A

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

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

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

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

                \[\leadsto y - \mathsf{fma}\left(\color{blue}{\frac{1}{2} + y}, \log y, z\right) \]
              6. lower-log.f6496.6

                \[\leadsto y - \mathsf{fma}\left(0.5 + y, \color{blue}{\log y}, z\right) \]
            5. Applied rewrites96.6%

              \[\leadsto \color{blue}{y - \mathsf{fma}\left(0.5 + y, \log y, z\right)} \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 6: 69.9% accurate, 1.0× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\ \mathbf{if}\;x \leq -126:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;x \leq 510:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, -z\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
          (FPCore (x y z)
           :precision binary64
           (let* ((t_0 (- (+ (/ 1.0 (/ 1.0 x)) y) z)))
             (if (<= x -126.0) t_0 (if (<= x 510.0) (fma -0.5 (log y) (- z)) t_0))))
          double code(double x, double y, double z) {
          	double t_0 = ((1.0 / (1.0 / x)) + y) - z;
          	double tmp;
          	if (x <= -126.0) {
          		tmp = t_0;
          	} else if (x <= 510.0) {
          		tmp = fma(-0.5, log(y), -z);
          	} else {
          		tmp = t_0;
          	}
          	return tmp;
          }
          
          function code(x, y, z)
          	t_0 = Float64(Float64(Float64(1.0 / Float64(1.0 / x)) + y) - z)
          	tmp = 0.0
          	if (x <= -126.0)
          		tmp = t_0;
          	elseif (x <= 510.0)
          		tmp = fma(-0.5, log(y), Float64(-z));
          	else
          		tmp = t_0;
          	end
          	return tmp
          end
          
          code[x_, y_, z_] := Block[{t$95$0 = N[(N[(N[(1.0 / N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[x, -126.0], t$95$0, If[LessEqual[x, 510.0], N[(-0.5 * N[Log[y], $MachinePrecision] + (-z)), $MachinePrecision], t$95$0]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \left(\frac{1}{\frac{1}{x}} + y\right) - z\\
          \mathbf{if}\;x \leq -126:\\
          \;\;\;\;t\_0\\
          
          \mathbf{elif}\;x \leq 510:\\
          \;\;\;\;\mathsf{fma}\left(-0.5, \log y, -z\right)\\
          
          \mathbf{else}:\\
          \;\;\;\;t\_0\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if x < -126 or 510 < x

            1. Initial program 99.9%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Step-by-step derivation
              1. lift--.f64N/A

                \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
              2. flip--N/A

                \[\leadsto \left(\color{blue}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}} + y\right) - z \]
              3. clear-numN/A

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

                \[\leadsto \left(\color{blue}{\frac{1}{\frac{x + \left(y + \frac{1}{2}\right) \cdot \log y}{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}}} + y\right) - z \]
              5. clear-numN/A

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}}}} + y\right) - z \]
              6. flip--N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              7. lift--.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              8. lower-/.f6499.7

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x - \left(y + 0.5\right) \cdot \log y}}} + y\right) - z \]
              9. lift--.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              10. sub-negN/A

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

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + x}}} + y\right) - z \]
              12. lift-*.f64N/A

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

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + x}} + y\right) - z \]
              14. lower-fma.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, x\right)}}} + y\right) - z \]
            4. Applied rewrites99.7%

              \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{\mathsf{fma}\left(-0.5 - y, \log y, x\right)}}} + y\right) - z \]
            5. Taylor expanded in x around inf

              \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
            6. Step-by-step derivation
              1. lower-/.f6482.7

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
            7. Applied rewrites82.7%

              \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]

            if -126 < x < 510

            1. Initial program 99.8%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Taylor expanded in x around 0

              \[\leadsto \color{blue}{y - \left(z + \log y \cdot \left(\frac{1}{2} + y\right)\right)} \]
            4. Step-by-step derivation
              1. lower--.f64N/A

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

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

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

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

                \[\leadsto y - \mathsf{fma}\left(\color{blue}{\frac{1}{2} + y}, \log y, z\right) \]
              6. lower-log.f6498.3

                \[\leadsto y - \mathsf{fma}\left(0.5 + y, \color{blue}{\log y}, z\right) \]
            5. Applied rewrites98.3%

              \[\leadsto \color{blue}{y - \mathsf{fma}\left(0.5 + y, \log y, z\right)} \]
            6. Taylor expanded in y around 0

              \[\leadsto -1 \cdot \color{blue}{\left(z + \frac{1}{2} \cdot \log y\right)} \]
            7. Step-by-step derivation
              1. Applied rewrites62.8%

                \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\log y}, -z\right) \]
            8. Recombined 2 regimes into one program.
            9. Add Preprocessing

            Alternative 7: 99.2% accurate, 1.0× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 5.1 \cdot 10^{-12}:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\ \mathbf{else}:\\ \;\;\;\;\left(\mathsf{fma}\left(-y, \log y, y\right) + x\right) - z\\ \end{array} \end{array} \]
            (FPCore (x y z)
             :precision binary64
             (if (<= y 5.1e-12)
               (- (fma -0.5 (log y) x) z)
               (- (+ (fma (- y) (log y) y) x) z)))
            double code(double x, double y, double z) {
            	double tmp;
            	if (y <= 5.1e-12) {
            		tmp = fma(-0.5, log(y), x) - z;
            	} else {
            		tmp = (fma(-y, log(y), y) + x) - z;
            	}
            	return tmp;
            }
            
            function code(x, y, z)
            	tmp = 0.0
            	if (y <= 5.1e-12)
            		tmp = Float64(fma(-0.5, log(y), x) - z);
            	else
            		tmp = Float64(Float64(fma(Float64(-y), log(y), y) + x) - z);
            	end
            	return tmp
            end
            
            code[x_, y_, z_] := If[LessEqual[y, 5.1e-12], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], N[(N[(N[((-y) * N[Log[y], $MachinePrecision] + y), $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision]]
            
            \begin{array}{l}
            
            \\
            \begin{array}{l}
            \mathbf{if}\;y \leq 5.1 \cdot 10^{-12}:\\
            \;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
            
            \mathbf{else}:\\
            \;\;\;\;\left(\mathsf{fma}\left(-y, \log y, y\right) + x\right) - z\\
            
            
            \end{array}
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if y < 5.09999999999999968e-12

              1. Initial program 100.0%

                \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
              2. Add Preprocessing
              3. Taylor expanded in y around 0

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

                  \[\leadsto x - \color{blue}{\left(\frac{1}{2} \cdot \log y + z\right)} \]
                2. associate--r+N/A

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

                  \[\leadsto \color{blue}{\left(x - \frac{1}{2} \cdot \log y\right) - z} \]
                4. sub-negN/A

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

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

                  \[\leadsto \left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) \cdot \log y} + x\right) - z \]
                7. metadata-evalN/A

                  \[\leadsto \left(\color{blue}{\frac{-1}{2}} \cdot \log y + x\right) - z \]
                8. lower-fma.f64N/A

                  \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{-1}{2}, \log y, x\right)} - z \]
                9. lower-log.f6499.8

                  \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\log y}, x\right) - z \]
              5. Applied rewrites99.8%

                \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, \log y, x\right) - z} \]

              if 5.09999999999999968e-12 < y

              1. Initial program 99.7%

                \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
              2. Add Preprocessing
              3. Step-by-step derivation
                1. lift-+.f64N/A

                  \[\leadsto \color{blue}{\left(\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right) + y\right)} - z \]
                2. lift--.f64N/A

                  \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
                3. sub-negN/A

                  \[\leadsto \left(\color{blue}{\left(x + \left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right)\right)} + y\right) - z \]
                4. associate-+l+N/A

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

                  \[\leadsto \color{blue}{\left(x + \left(\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + y\right)\right)} - z \]
                6. lift-*.f64N/A

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

                  \[\leadsto \left(x + \left(\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + y\right)\right) - z \]
                8. lower-fma.f64N/A

                  \[\leadsto \left(x + \color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, y\right)}\right) - z \]
                9. lift-+.f64N/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\mathsf{neg}\left(\color{blue}{\left(y + \frac{1}{2}\right)}\right), \log y, y\right)\right) - z \]
                10. +-commutativeN/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\mathsf{neg}\left(\color{blue}{\left(\frac{1}{2} + y\right)}\right), \log y, y\right)\right) - z \]
                11. distribute-neg-inN/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) + \left(\mathsf{neg}\left(y\right)\right)}, \log y, y\right)\right) - z \]
                12. unsub-negN/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) - y}, \log y, y\right)\right) - z \]
                13. lower--.f64N/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) - y}, \log y, y\right)\right) - z \]
                14. metadata-eval99.9

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{-0.5} - y, \log y, y\right)\right) - z \]
              4. Applied rewrites99.9%

                \[\leadsto \color{blue}{\left(x + \mathsf{fma}\left(-0.5 - y, \log y, y\right)\right)} - z \]
              5. Taylor expanded in y around inf

                \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{-1 \cdot y}, \log y, y\right)\right) - z \]
              6. Step-by-step derivation
                1. mul-1-negN/A

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{\mathsf{neg}\left(y\right)}, \log y, y\right)\right) - z \]
                2. lower-neg.f6499.1

                  \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{-y}, \log y, y\right)\right) - z \]
              7. Applied rewrites99.1%

                \[\leadsto \left(x + \mathsf{fma}\left(\color{blue}{-y}, \log y, y\right)\right) - z \]
            3. Recombined 2 regimes into one program.
            4. Final simplification99.4%

              \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 5.1 \cdot 10^{-12}:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\ \mathbf{else}:\\ \;\;\;\;\left(\mathsf{fma}\left(-y, \log y, y\right) + x\right) - z\\ \end{array} \]
            5. Add Preprocessing

            Alternative 8: 83.2% accurate, 1.0× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 4.2 \cdot 10^{+197}:\\ \;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\ \mathbf{else}:\\ \;\;\;\;\left(1 - \log y\right) \cdot y\\ \end{array} \end{array} \]
            (FPCore (x y z)
             :precision binary64
             (if (<= y 4.2e+197) (- (fma -0.5 (log y) x) z) (* (- 1.0 (log y)) y)))
            double code(double x, double y, double z) {
            	double tmp;
            	if (y <= 4.2e+197) {
            		tmp = fma(-0.5, log(y), x) - z;
            	} else {
            		tmp = (1.0 - log(y)) * y;
            	}
            	return tmp;
            }
            
            function code(x, y, z)
            	tmp = 0.0
            	if (y <= 4.2e+197)
            		tmp = Float64(fma(-0.5, log(y), x) - z);
            	else
            		tmp = Float64(Float64(1.0 - log(y)) * y);
            	end
            	return tmp
            end
            
            code[x_, y_, z_] := If[LessEqual[y, 4.2e+197], N[(N[(-0.5 * N[Log[y], $MachinePrecision] + x), $MachinePrecision] - z), $MachinePrecision], N[(N[(1.0 - N[Log[y], $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]]
            
            \begin{array}{l}
            
            \\
            \begin{array}{l}
            \mathbf{if}\;y \leq 4.2 \cdot 10^{+197}:\\
            \;\;\;\;\mathsf{fma}\left(-0.5, \log y, x\right) - z\\
            
            \mathbf{else}:\\
            \;\;\;\;\left(1 - \log y\right) \cdot y\\
            
            
            \end{array}
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if y < 4.20000000000000013e197

              1. Initial program 99.9%

                \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
              2. Add Preprocessing
              3. Taylor expanded in y around 0

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

                  \[\leadsto x - \color{blue}{\left(\frac{1}{2} \cdot \log y + z\right)} \]
                2. associate--r+N/A

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

                  \[\leadsto \color{blue}{\left(x - \frac{1}{2} \cdot \log y\right) - z} \]
                4. sub-negN/A

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

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

                  \[\leadsto \left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right) \cdot \log y} + x\right) - z \]
                7. metadata-evalN/A

                  \[\leadsto \left(\color{blue}{\frac{-1}{2}} \cdot \log y + x\right) - z \]
                8. lower-fma.f64N/A

                  \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{-1}{2}, \log y, x\right)} - z \]
                9. lower-log.f6483.6

                  \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\log y}, x\right) - z \]
              5. Applied rewrites83.6%

                \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, \log y, x\right) - z} \]

              if 4.20000000000000013e197 < y

              1. Initial program 99.7%

                \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
              2. Add Preprocessing
              3. Taylor expanded in y around inf

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

                  \[\leadsto \color{blue}{\left(1 - -1 \cdot \log \left(\frac{1}{y}\right)\right) \cdot y} \]
                2. mul-1-negN/A

                  \[\leadsto \left(1 - \color{blue}{\left(\mathsf{neg}\left(\log \left(\frac{1}{y}\right)\right)\right)}\right) \cdot y \]
                3. log-recN/A

                  \[\leadsto \left(1 - \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(\log y\right)\right)}\right)\right)\right) \cdot y \]
                4. remove-double-negN/A

                  \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
                5. lower-*.f64N/A

                  \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]
                6. lower--.f64N/A

                  \[\leadsto \color{blue}{\left(1 - \log y\right)} \cdot y \]
                7. lower-log.f6482.0

                  \[\leadsto \left(1 - \color{blue}{\log y}\right) \cdot y \]
              5. Applied rewrites82.0%

                \[\leadsto \color{blue}{\left(1 - \log y\right) \cdot y} \]
            3. Recombined 2 regimes into one program.
            4. Add Preprocessing

            Alternative 9: 57.8% accurate, 4.1× speedup?

            \[\begin{array}{l} \\ \left(\frac{1}{\frac{1}{x}} + y\right) - z \end{array} \]
            (FPCore (x y z) :precision binary64 (- (+ (/ 1.0 (/ 1.0 x)) y) z))
            double code(double x, double y, double z) {
            	return ((1.0 / (1.0 / x)) + y) - z;
            }
            
            real(8) function code(x, y, z)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                real(8), intent (in) :: z
                code = ((1.0d0 / (1.0d0 / x)) + y) - z
            end function
            
            public static double code(double x, double y, double z) {
            	return ((1.0 / (1.0 / x)) + y) - z;
            }
            
            def code(x, y, z):
            	return ((1.0 / (1.0 / x)) + y) - z
            
            function code(x, y, z)
            	return Float64(Float64(Float64(1.0 / Float64(1.0 / x)) + y) - z)
            end
            
            function tmp = code(x, y, z)
            	tmp = ((1.0 / (1.0 / x)) + y) - z;
            end
            
            code[x_, y_, z_] := N[(N[(N[(1.0 / N[(1.0 / x), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \left(\frac{1}{\frac{1}{x}} + y\right) - z
            \end{array}
            
            Derivation
            1. Initial program 99.8%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Step-by-step derivation
              1. lift--.f64N/A

                \[\leadsto \left(\color{blue}{\left(x - \left(y + \frac{1}{2}\right) \cdot \log y\right)} + y\right) - z \]
              2. flip--N/A

                \[\leadsto \left(\color{blue}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}} + y\right) - z \]
              3. clear-numN/A

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

                \[\leadsto \left(\color{blue}{\frac{1}{\frac{x + \left(y + \frac{1}{2}\right) \cdot \log y}{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}}} + y\right) - z \]
              5. clear-numN/A

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{x \cdot x - \left(\left(y + \frac{1}{2}\right) \cdot \log y\right) \cdot \left(\left(y + \frac{1}{2}\right) \cdot \log y\right)}{x + \left(y + \frac{1}{2}\right) \cdot \log y}}}} + y\right) - z \]
              6. flip--N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              7. lift--.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              8. lower-/.f6499.7

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x - \left(y + 0.5\right) \cdot \log y}}} + y\right) - z \]
              9. lift--.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{x - \left(y + \frac{1}{2}\right) \cdot \log y}}} + y\right) - z \]
              10. sub-negN/A

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

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right) \cdot \log y\right)\right) + x}}} + y\right) - z \]
              12. lift-*.f64N/A

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

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right)\right) \cdot \log y} + x}} + y\right) - z \]
              14. lower-fma.f64N/A

                \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(\left(y + \frac{1}{2}\right)\right), \log y, x\right)}}} + y\right) - z \]
            4. Applied rewrites99.7%

              \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{\mathsf{fma}\left(-0.5 - y, \log y, x\right)}}} + y\right) - z \]
            5. Taylor expanded in x around inf

              \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
            6. Step-by-step derivation
              1. lower-/.f6461.5

                \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
            7. Applied rewrites61.5%

              \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{x}}} + y\right) - z \]
            8. Add Preprocessing

            Alternative 10: 30.0% accurate, 39.3× speedup?

            \[\begin{array}{l} \\ -z \end{array} \]
            (FPCore (x y z) :precision binary64 (- z))
            double code(double x, double y, double z) {
            	return -z;
            }
            
            real(8) function code(x, y, z)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                real(8), intent (in) :: z
                code = -z
            end function
            
            public static double code(double x, double y, double z) {
            	return -z;
            }
            
            def code(x, y, z):
            	return -z
            
            function code(x, y, z)
            	return Float64(-z)
            end
            
            function tmp = code(x, y, z)
            	tmp = -z;
            end
            
            code[x_, y_, z_] := (-z)
            
            \begin{array}{l}
            
            \\
            -z
            \end{array}
            
            Derivation
            1. Initial program 99.8%

              \[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
            2. Add Preprocessing
            3. Taylor expanded in z around inf

              \[\leadsto \color{blue}{-1 \cdot z} \]
            4. Step-by-step derivation
              1. mul-1-negN/A

                \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
              2. lower-neg.f6434.4

                \[\leadsto \color{blue}{-z} \]
            5. Applied rewrites34.4%

              \[\leadsto \color{blue}{-z} \]
            6. Add Preprocessing

            Developer Target 1: 99.8% accurate, 1.0× speedup?

            \[\begin{array}{l} \\ \left(\left(y + x\right) - z\right) - \left(y + 0.5\right) \cdot \log y \end{array} \]
            (FPCore (x y z) :precision binary64 (- (- (+ y x) z) (* (+ y 0.5) (log y))))
            double code(double x, double y, double z) {
            	return ((y + x) - z) - ((y + 0.5) * log(y));
            }
            
            real(8) function code(x, y, z)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                real(8), intent (in) :: z
                code = ((y + x) - z) - ((y + 0.5d0) * log(y))
            end function
            
            public static double code(double x, double y, double z) {
            	return ((y + x) - z) - ((y + 0.5) * Math.log(y));
            }
            
            def code(x, y, z):
            	return ((y + x) - z) - ((y + 0.5) * math.log(y))
            
            function code(x, y, z)
            	return Float64(Float64(Float64(y + x) - z) - Float64(Float64(y + 0.5) * log(y)))
            end
            
            function tmp = code(x, y, z)
            	tmp = ((y + x) - z) - ((y + 0.5) * log(y));
            end
            
            code[x_, y_, z_] := N[(N[(N[(y + x), $MachinePrecision] - z), $MachinePrecision] - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \left(\left(y + x\right) - z\right) - \left(y + 0.5\right) \cdot \log y
            \end{array}
            

            Reproduce

            ?
            herbie shell --seed 2024296 
            (FPCore (x y z)
              :name "Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2"
              :precision binary64
            
              :alt
              (! :herbie-platform default (- (- (+ y x) z) (* (+ y 1/2) (log y))))
            
              (- (+ (- x (* (+ y 0.5) (log y))) y) z))