Numeric.SpecFunctions.Extra:bd0 from math-functions-0.1.5.2

Percentage Accurate: 77.2% → 99.5%
Time: 5.7s
Alternatives: 6
Speedup: 0.5×

Specification

?
\[\begin{array}{l} \\ x \cdot \log \left(\frac{x}{y}\right) - z \end{array} \]
(FPCore (x y z) :precision binary64 (- (* x (log (/ x y))) z))
double code(double x, double y, double z) {
	return (x * log((x / y))) - z;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = (x * log((x / y))) - z
end function
public static double code(double x, double y, double z) {
	return (x * Math.log((x / y))) - z;
}
def code(x, y, z):
	return (x * math.log((x / y))) - z
function code(x, y, z)
	return Float64(Float64(x * log(Float64(x / y))) - z)
end
function tmp = code(x, y, z)
	tmp = (x * log((x / y))) - z;
end
code[x_, y_, z_] := N[(N[(x * N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}

\\
x \cdot \log \left(\frac{x}{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 6 alternatives:

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

Initial Program: 77.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x \cdot \log \left(\frac{x}{y}\right) - z \end{array} \]
(FPCore (x y z) :precision binary64 (- (* x (log (/ x y))) z))
double code(double x, double y, double z) {
	return (x * log((x / y))) - z;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = (x * log((x / y))) - z
end function
public static double code(double x, double y, double z) {
	return (x * Math.log((x / y))) - z;
}
def code(x, y, z):
	return (x * math.log((x / y))) - z
function code(x, y, z)
	return Float64(Float64(x * log(Float64(x / y))) - z)
end
function tmp = code(x, y, z)
	tmp = (x * log((x / y))) - z;
end
code[x_, y_, z_] := N[(N[(x * N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]
\begin{array}{l}

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

Alternative 1: 99.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -5 \cdot 10^{-310}:\\ \;\;\;\;x \cdot \left(\log \left(-x\right) - \log \left(-y\right)\right) - z\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(\log x - \log y\right) - z\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (if (<= y -5e-310)
   (- (* x (- (log (- x)) (log (- y)))) z)
   (- (* x (- (log x) (log y))) z)))
double code(double x, double y, double z) {
	double tmp;
	if (y <= -5e-310) {
		tmp = (x * (log(-x) - log(-y))) - z;
	} else {
		tmp = (x * (log(x) - log(y))) - z;
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8) :: tmp
    if (y <= (-5d-310)) then
        tmp = (x * (log(-x) - log(-y))) - z
    else
        tmp = (x * (log(x) - log(y))) - z
    end if
    code = tmp
end function
public static double code(double x, double y, double z) {
	double tmp;
	if (y <= -5e-310) {
		tmp = (x * (Math.log(-x) - Math.log(-y))) - z;
	} else {
		tmp = (x * (Math.log(x) - Math.log(y))) - z;
	}
	return tmp;
}
def code(x, y, z):
	tmp = 0
	if y <= -5e-310:
		tmp = (x * (math.log(-x) - math.log(-y))) - z
	else:
		tmp = (x * (math.log(x) - math.log(y))) - z
	return tmp
function code(x, y, z)
	tmp = 0.0
	if (y <= -5e-310)
		tmp = Float64(Float64(x * Float64(log(Float64(-x)) - log(Float64(-y)))) - z);
	else
		tmp = Float64(Float64(x * Float64(log(x) - log(y))) - z);
	end
	return tmp
end
function tmp_2 = code(x, y, z)
	tmp = 0.0;
	if (y <= -5e-310)
		tmp = (x * (log(-x) - log(-y))) - z;
	else
		tmp = (x * (log(x) - log(y))) - z;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_] := If[LessEqual[y, -5e-310], N[(N[(x * N[(N[Log[(-x)], $MachinePrecision] - N[Log[(-y)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision], N[(N[(x * N[(N[Log[x], $MachinePrecision] - N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -5 \cdot 10^{-310}:\\
\;\;\;\;x \cdot \left(\log \left(-x\right) - \log \left(-y\right)\right) - z\\

\mathbf{else}:\\
\;\;\;\;x \cdot \left(\log x - \log y\right) - z\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -4.999999999999985e-310

    1. Initial program 77.3%

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

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

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

        \[\leadsto x \cdot \log \color{blue}{\left(\frac{\mathsf{neg}\left(x\right)}{\mathsf{neg}\left(y\right)}\right)} - z \]
      4. log-divN/A

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

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

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

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

        \[\leadsto x \cdot \left(\log \left(-x\right) - \color{blue}{\log \left(\mathsf{neg}\left(y\right)\right)}\right) - z \]
      9. lower-neg.f6499.5

        \[\leadsto x \cdot \left(\log \left(-x\right) - \log \color{blue}{\left(-y\right)}\right) - z \]
    4. Applied rewrites99.5%

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

    if -4.999999999999985e-310 < y

    1. Initial program 80.1%

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

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

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

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

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

        \[\leadsto x \cdot \left(\color{blue}{\log x} - \log y\right) - z \]
      6. lower-log.f6499.6

        \[\leadsto x \cdot \left(\log x - \color{blue}{\log y}\right) - z \]
    4. Applied rewrites99.6%

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

Alternative 2: 86.6% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \log \left(\frac{x}{y}\right)\\ t_1 := x \cdot t\_0 - z\\ \mathbf{if}\;t\_1 \leq -\infty:\\ \;\;\;\;-z\\ \mathbf{elif}\;t\_1 \leq 2 \cdot 10^{+307}:\\ \;\;\;\;\mathsf{fma}\left(t\_0, x, -z\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\log x - \log y\right) \cdot x\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (let* ((t_0 (log (/ x y))) (t_1 (- (* x t_0) z)))
   (if (<= t_1 (- INFINITY))
     (- z)
     (if (<= t_1 2e+307) (fma t_0 x (- z)) (* (- (log x) (log y)) x)))))
double code(double x, double y, double z) {
	double t_0 = log((x / y));
	double t_1 = (x * t_0) - z;
	double tmp;
	if (t_1 <= -((double) INFINITY)) {
		tmp = -z;
	} else if (t_1 <= 2e+307) {
		tmp = fma(t_0, x, -z);
	} else {
		tmp = (log(x) - log(y)) * x;
	}
	return tmp;
}
function code(x, y, z)
	t_0 = log(Float64(x / y))
	t_1 = Float64(Float64(x * t_0) - z)
	tmp = 0.0
	if (t_1 <= Float64(-Inf))
		tmp = Float64(-z);
	elseif (t_1 <= 2e+307)
		tmp = fma(t_0, x, Float64(-z));
	else
		tmp = Float64(Float64(log(x) - log(y)) * x);
	end
	return tmp
end
code[x_, y_, z_] := Block[{t$95$0 = N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(x * t$95$0), $MachinePrecision] - z), $MachinePrecision]}, If[LessEqual[t$95$1, (-Infinity)], (-z), If[LessEqual[t$95$1, 2e+307], N[(t$95$0 * x + (-z)), $MachinePrecision], N[(N[(N[Log[x], $MachinePrecision] - N[Log[y], $MachinePrecision]), $MachinePrecision] * x), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \log \left(\frac{x}{y}\right)\\
t_1 := x \cdot t\_0 - z\\
\mathbf{if}\;t\_1 \leq -\infty:\\
\;\;\;\;-z\\

\mathbf{elif}\;t\_1 \leq 2 \cdot 10^{+307}:\\
\;\;\;\;\mathsf{fma}\left(t\_0, x, -z\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\log x - \log y\right) \cdot x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z) < -inf.0

    1. Initial program 7.3%

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

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
      2. lower-neg.f6468.8

        \[\leadsto \color{blue}{-z} \]
    5. Applied rewrites68.8%

      \[\leadsto \color{blue}{-z} \]

    if -inf.0 < (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z) < 1.99999999999999997e307

    1. Initial program 99.3%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        \[\leadsto \mathsf{fma}\left(\log \color{blue}{\left(\frac{x}{y}\right)}, x, -1 \cdot z\right) \]
      14. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, \color{blue}{\mathsf{neg}\left(z\right)}\right) \]
      15. lower-neg.f6499.4

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

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

    if 1.99999999999999997e307 < (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z)

    1. Initial program 7.1%

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

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

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

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

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

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

        \[\leadsto \left(-1 \cdot \log \left(\frac{1}{x}\right) + \color{blue}{-1 \cdot \log y}\right) \cdot x \]
      6. fp-cancel-sign-sub-invN/A

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

        \[\leadsto \left(-1 \cdot \log \left(\frac{1}{x}\right) - \color{blue}{1} \cdot \log y\right) \cdot x \]
      8. *-lft-identityN/A

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

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

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

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

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

        \[\leadsto \left(\color{blue}{\log x} - \log y\right) \cdot x \]
      14. lower-log.f6445.6

        \[\leadsto \left(\log x - \color{blue}{\log y}\right) \cdot x \]
    5. Applied rewrites45.6%

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

Alternative 3: 86.2% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \log \left(\frac{x}{y}\right)\\ t_1 := x \cdot t\_0 - z\\ \mathbf{if}\;t\_1 \leq -\infty \lor \neg \left(t\_1 \leq 2 \cdot 10^{+288}\right):\\ \;\;\;\;-z\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(t\_0, x, -z\right)\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (let* ((t_0 (log (/ x y))) (t_1 (- (* x t_0) z)))
   (if (or (<= t_1 (- INFINITY)) (not (<= t_1 2e+288)))
     (- z)
     (fma t_0 x (- z)))))
double code(double x, double y, double z) {
	double t_0 = log((x / y));
	double t_1 = (x * t_0) - z;
	double tmp;
	if ((t_1 <= -((double) INFINITY)) || !(t_1 <= 2e+288)) {
		tmp = -z;
	} else {
		tmp = fma(t_0, x, -z);
	}
	return tmp;
}
function code(x, y, z)
	t_0 = log(Float64(x / y))
	t_1 = Float64(Float64(x * t_0) - z)
	tmp = 0.0
	if ((t_1 <= Float64(-Inf)) || !(t_1 <= 2e+288))
		tmp = Float64(-z);
	else
		tmp = fma(t_0, x, Float64(-z));
	end
	return tmp
end
code[x_, y_, z_] := Block[{t$95$0 = N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(x * t$95$0), $MachinePrecision] - z), $MachinePrecision]}, If[Or[LessEqual[t$95$1, (-Infinity)], N[Not[LessEqual[t$95$1, 2e+288]], $MachinePrecision]], (-z), N[(t$95$0 * x + (-z)), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \log \left(\frac{x}{y}\right)\\
t_1 := x \cdot t\_0 - z\\
\mathbf{if}\;t\_1 \leq -\infty \lor \neg \left(t\_1 \leq 2 \cdot 10^{+288}\right):\\
\;\;\;\;-z\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(t\_0, x, -z\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z) < -inf.0 or 2e288 < (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z)

    1. Initial program 11.8%

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

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
      2. lower-neg.f6456.1

        \[\leadsto \color{blue}{-z} \]
    5. Applied rewrites56.1%

      \[\leadsto \color{blue}{-z} \]

    if -inf.0 < (-.f64 (*.f64 x (log.f64 (/.f64 x y))) z) < 2e288

    1. Initial program 99.3%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        \[\leadsto \mathsf{fma}\left(\log \color{blue}{\left(\frac{x}{y}\right)}, x, -1 \cdot z\right) \]
      14. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, \color{blue}{\mathsf{neg}\left(z\right)}\right) \]
      15. lower-neg.f6499.3

        \[\leadsto \mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, \color{blue}{-z}\right) \]
    5. Applied rewrites99.3%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, -z\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification89.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \cdot \log \left(\frac{x}{y}\right) - z \leq -\infty \lor \neg \left(x \cdot \log \left(\frac{x}{y}\right) - z \leq 2 \cdot 10^{+288}\right):\\ \;\;\;\;-z\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, -z\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 90.3% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.35 \cdot 10^{-211}:\\ \;\;\;\;\mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, -z\right)\\ \mathbf{elif}\;x \leq -2 \cdot 10^{-306}:\\ \;\;\;\;-z\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(\log x - \log y\right) - z\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (if (<= x -1.35e-211)
   (fma (log (/ x y)) x (- z))
   (if (<= x -2e-306) (- z) (- (* x (- (log x) (log y))) z))))
double code(double x, double y, double z) {
	double tmp;
	if (x <= -1.35e-211) {
		tmp = fma(log((x / y)), x, -z);
	} else if (x <= -2e-306) {
		tmp = -z;
	} else {
		tmp = (x * (log(x) - log(y))) - z;
	}
	return tmp;
}
function code(x, y, z)
	tmp = 0.0
	if (x <= -1.35e-211)
		tmp = fma(log(Float64(x / y)), x, Float64(-z));
	elseif (x <= -2e-306)
		tmp = Float64(-z);
	else
		tmp = Float64(Float64(x * Float64(log(x) - log(y))) - z);
	end
	return tmp
end
code[x_, y_, z_] := If[LessEqual[x, -1.35e-211], N[(N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision] * x + (-z)), $MachinePrecision], If[LessEqual[x, -2e-306], (-z), N[(N[(x * N[(N[Log[x], $MachinePrecision] - N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.35 \cdot 10^{-211}:\\
\;\;\;\;\mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, -z\right)\\

\mathbf{elif}\;x \leq -2 \cdot 10^{-306}:\\
\;\;\;\;-z\\

\mathbf{else}:\\
\;\;\;\;x \cdot \left(\log x - \log y\right) - z\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.35e-211

    1. Initial program 84.4%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        \[\leadsto \mathsf{fma}\left(\log \color{blue}{\left(\frac{x}{y}\right)}, x, -1 \cdot z\right) \]
      14. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, \color{blue}{\mathsf{neg}\left(z\right)}\right) \]
      15. lower-neg.f6484.4

        \[\leadsto \mathsf{fma}\left(\log \left(\frac{x}{y}\right), x, \color{blue}{-z}\right) \]
    5. Applied rewrites84.4%

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

    if -1.35e-211 < x < -2.00000000000000006e-306

    1. Initial program 49.1%

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

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
      2. lower-neg.f6495.9

        \[\leadsto \color{blue}{-z} \]
    5. Applied rewrites95.9%

      \[\leadsto \color{blue}{-z} \]

    if -2.00000000000000006e-306 < x

    1. Initial program 80.1%

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

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

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

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

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

        \[\leadsto x \cdot \left(\color{blue}{\log x} - \log y\right) - z \]
      6. lower-log.f6499.6

        \[\leadsto x \cdot \left(\log x - \color{blue}{\log y}\right) - z \]
    4. Applied rewrites99.6%

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

Alternative 5: 65.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2.6 \cdot 10^{+54} \lor \neg \left(x \leq 1.5 \cdot 10^{+55}\right):\\ \;\;\;\;\log \left(\frac{x}{y}\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;-z\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (if (or (<= x -2.6e+54) (not (<= x 1.5e+55))) (* (log (/ x y)) x) (- z)))
double code(double x, double y, double z) {
	double tmp;
	if ((x <= -2.6e+54) || !(x <= 1.5e+55)) {
		tmp = log((x / y)) * x;
	} else {
		tmp = -z;
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8) :: tmp
    if ((x <= (-2.6d+54)) .or. (.not. (x <= 1.5d+55))) then
        tmp = log((x / y)) * x
    else
        tmp = -z
    end if
    code = tmp
end function
public static double code(double x, double y, double z) {
	double tmp;
	if ((x <= -2.6e+54) || !(x <= 1.5e+55)) {
		tmp = Math.log((x / y)) * x;
	} else {
		tmp = -z;
	}
	return tmp;
}
def code(x, y, z):
	tmp = 0
	if (x <= -2.6e+54) or not (x <= 1.5e+55):
		tmp = math.log((x / y)) * x
	else:
		tmp = -z
	return tmp
function code(x, y, z)
	tmp = 0.0
	if ((x <= -2.6e+54) || !(x <= 1.5e+55))
		tmp = Float64(log(Float64(x / y)) * x);
	else
		tmp = Float64(-z);
	end
	return tmp
end
function tmp_2 = code(x, y, z)
	tmp = 0.0;
	if ((x <= -2.6e+54) || ~((x <= 1.5e+55)))
		tmp = log((x / y)) * x;
	else
		tmp = -z;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_] := If[Or[LessEqual[x, -2.6e+54], N[Not[LessEqual[x, 1.5e+55]], $MachinePrecision]], N[(N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision] * x), $MachinePrecision], (-z)]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.6 \cdot 10^{+54} \lor \neg \left(x \leq 1.5 \cdot 10^{+55}\right):\\
\;\;\;\;\log \left(\frac{x}{y}\right) \cdot x\\

\mathbf{else}:\\
\;\;\;\;-z\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -2.60000000000000007e54 or 1.50000000000000008e55 < x

    1. Initial program 76.3%

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

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

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

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

        \[\leadsto \color{blue}{\log \left(\frac{x}{y}\right)} \cdot x \]
      4. lower-/.f6464.7

        \[\leadsto \log \color{blue}{\left(\frac{x}{y}\right)} \cdot x \]
    5. Applied rewrites64.7%

      \[\leadsto \color{blue}{\log \left(\frac{x}{y}\right) \cdot x} \]

    if -2.60000000000000007e54 < x < 1.50000000000000008e55

    1. Initial program 80.6%

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

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
      2. lower-neg.f6475.0

        \[\leadsto \color{blue}{-z} \]
    5. Applied rewrites75.0%

      \[\leadsto \color{blue}{-z} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -2.6 \cdot 10^{+54} \lor \neg \left(x \leq 1.5 \cdot 10^{+55}\right):\\ \;\;\;\;\log \left(\frac{x}{y}\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;-z\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 50.1% accurate, 40.0× speedup?

\[\begin{array}{l} \\ -z \end{array} \]
(FPCore (x y z) :precision binary64 (- z))
double code(double x, double y, double z) {
	return -z;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    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 78.8%

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

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

      \[\leadsto \color{blue}{\mathsf{neg}\left(z\right)} \]
    2. lower-neg.f6451.7

      \[\leadsto \color{blue}{-z} \]
  5. Applied rewrites51.7%

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

Developer Target 1: 88.1% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y < 7.595077799083773 \cdot 10^{-308}:\\ \;\;\;\;x \cdot \log \left(\frac{x}{y}\right) - z\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(\log x - \log y\right) - z\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (if (< y 7.595077799083773e-308)
   (- (* x (log (/ x y))) z)
   (- (* x (- (log x) (log y))) z)))
double code(double x, double y, double z) {
	double tmp;
	if (y < 7.595077799083773e-308) {
		tmp = (x * log((x / y))) - z;
	} else {
		tmp = (x * (log(x) - log(y))) - z;
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8) :: tmp
    if (y < 7.595077799083773d-308) then
        tmp = (x * log((x / y))) - z
    else
        tmp = (x * (log(x) - log(y))) - z
    end if
    code = tmp
end function
public static double code(double x, double y, double z) {
	double tmp;
	if (y < 7.595077799083773e-308) {
		tmp = (x * Math.log((x / y))) - z;
	} else {
		tmp = (x * (Math.log(x) - Math.log(y))) - z;
	}
	return tmp;
}
def code(x, y, z):
	tmp = 0
	if y < 7.595077799083773e-308:
		tmp = (x * math.log((x / y))) - z
	else:
		tmp = (x * (math.log(x) - math.log(y))) - z
	return tmp
function code(x, y, z)
	tmp = 0.0
	if (y < 7.595077799083773e-308)
		tmp = Float64(Float64(x * log(Float64(x / y))) - z);
	else
		tmp = Float64(Float64(x * Float64(log(x) - log(y))) - z);
	end
	return tmp
end
function tmp_2 = code(x, y, z)
	tmp = 0.0;
	if (y < 7.595077799083773e-308)
		tmp = (x * log((x / y))) - z;
	else
		tmp = (x * (log(x) - log(y))) - z;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_] := If[Less[y, 7.595077799083773e-308], N[(N[(x * N[Log[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision], N[(N[(x * N[(N[Log[x], $MachinePrecision] - N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y < 7.595077799083773 \cdot 10^{-308}:\\
\;\;\;\;x \cdot \log \left(\frac{x}{y}\right) - z\\

\mathbf{else}:\\
\;\;\;\;x \cdot \left(\log x - \log y\right) - z\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2025017 
(FPCore (x y z)
  :name "Numeric.SpecFunctions.Extra:bd0 from math-functions-0.1.5.2"
  :precision binary64

  :alt
  (! :herbie-platform default (if (< y 7595077799083773/100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (- (* x (log (/ x y))) z) (- (* x (- (log x) (log y))) z)))

  (- (* x (log (/ x y))) z))