Numeric.SpecFunctions:logGammaL from math-functions-0.1.5.2

Percentage Accurate: 99.6% → 99.6%
Time: 21.0s
Alternatives: 14
Speedup: 1.0×

Specification

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

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

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 14 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: 99.6% accurate, 1.0× speedup?

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

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

Alternative 1: 99.6% accurate, 0.8× speedup?

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

\\
\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Step-by-step derivation
    1. associate-+l-99.6%

      \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
    2. associate--l+99.6%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
    3. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
    4. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
    5. *-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
    6. distribute-rgt-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
    7. fma-udef99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
    8. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
    9. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
    10. distribute-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
    11. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
    12. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
    13. unsub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
  4. Add Preprocessing
  5. Final simplification99.6%

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

Alternative 2: 77.1% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\log z \leq -660 \lor \neg \left(\log z \leq 162.8\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log \left(z \cdot \left(x + y\right)\right) + \log t \cdot \left(a - 0.5\right)\right) - t\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= (log z) -660.0) (not (<= (log z) 162.8)))
   (- (+ (log y) (* (log t) a)) t)
   (- (+ (log (* z (+ x y))) (* (log t) (- a 0.5))) t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((log(z) <= -660.0) || !(log(z) <= 162.8)) {
		tmp = (log(y) + (log(t) * a)) - t;
	} else {
		tmp = (log((z * (x + y))) + (log(t) * (a - 0.5))) - t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if ((log(z) <= (-660.0d0)) .or. (.not. (log(z) <= 162.8d0))) then
        tmp = (log(y) + (log(t) * a)) - t
    else
        tmp = (log((z * (x + y))) + (log(t) * (a - 0.5d0))) - t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((Math.log(z) <= -660.0) || !(Math.log(z) <= 162.8)) {
		tmp = (Math.log(y) + (Math.log(t) * a)) - t;
	} else {
		tmp = (Math.log((z * (x + y))) + (Math.log(t) * (a - 0.5))) - t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (math.log(z) <= -660.0) or not (math.log(z) <= 162.8):
		tmp = (math.log(y) + (math.log(t) * a)) - t
	else:
		tmp = (math.log((z * (x + y))) + (math.log(t) * (a - 0.5))) - t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((log(z) <= -660.0) || !(log(z) <= 162.8))
		tmp = Float64(Float64(log(y) + Float64(log(t) * a)) - t);
	else
		tmp = Float64(Float64(log(Float64(z * Float64(x + y))) + Float64(log(t) * Float64(a - 0.5))) - t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((log(z) <= -660.0) || ~((log(z) <= 162.8)))
		tmp = (log(y) + (log(t) * a)) - t;
	else
		tmp = (log((z * (x + y))) + (log(t) * (a - 0.5))) - t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[N[Log[z], $MachinePrecision], -660.0], N[Not[LessEqual[N[Log[z], $MachinePrecision], 162.8]], $MachinePrecision]], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[(N[Log[N[(z * N[(x + y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * N[(a - 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\log z \leq -660 \lor \neg \left(\log z \leq 162.8\right):\\
\;\;\;\;\left(\log y + \log t \cdot a\right) - t\\

\mathbf{else}:\\
\;\;\;\;\left(\log \left(z \cdot \left(x + y\right)\right) + \log t \cdot \left(a - 0.5\right)\right) - t\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (log.f64 z) < -660 or 162.80000000000001 < (log.f64 z)

    1. Initial program 99.7%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 64.0%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around inf 54.3%

      \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative54.3%

        \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
    6. Simplified54.3%

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

    if -660 < (log.f64 z) < 162.80000000000001

    1. Initial program 99.5%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.5%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.6%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.6%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. associate-+r-99.5%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \mathsf{fma}\left(\log t, 0.5 - a, t\right)} \]
      2. fma-udef99.5%

        \[\leadsto \left(\log \left(x + y\right) + \log z\right) - \color{blue}{\left(\log t \cdot \left(0.5 - a\right) + t\right)} \]
      3. associate--r+99.5%

        \[\leadsto \color{blue}{\left(\left(\log \left(x + y\right) + \log z\right) - \log t \cdot \left(0.5 - a\right)\right) - t} \]
      4. +-commutative99.5%

        \[\leadsto \left(\color{blue}{\left(\log z + \log \left(x + y\right)\right)} - \log t \cdot \left(0.5 - a\right)\right) - t \]
      5. sum-log95.4%

        \[\leadsto \left(\color{blue}{\log \left(z \cdot \left(x + y\right)\right)} - \log t \cdot \left(0.5 - a\right)\right) - t \]
    6. Applied egg-rr95.4%

      \[\leadsto \color{blue}{\left(\log \left(z \cdot \left(x + y\right)\right) - \log t \cdot \left(0.5 - a\right)\right) - t} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification79.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\log z \leq -660 \lor \neg \left(\log z \leq 162.8\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log \left(z \cdot \left(x + y\right)\right) + \log t \cdot \left(a - 0.5\right)\right) - t\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 67.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 0.52\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log y + \left(\log z + \log t \cdot -0.5\right)\right) - t\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= a -5.2) (not (<= a 0.52)))
   (- (+ (log y) (* (log t) a)) t)
   (- (+ (log y) (+ (log z) (* (log t) -0.5))) t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 0.52)) {
		tmp = (log(y) + (log(t) * a)) - t;
	} else {
		tmp = (log(y) + (log(z) + (log(t) * -0.5))) - t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if ((a <= (-5.2d0)) .or. (.not. (a <= 0.52d0))) then
        tmp = (log(y) + (log(t) * a)) - t
    else
        tmp = (log(y) + (log(z) + (log(t) * (-0.5d0)))) - t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 0.52)) {
		tmp = (Math.log(y) + (Math.log(t) * a)) - t;
	} else {
		tmp = (Math.log(y) + (Math.log(z) + (Math.log(t) * -0.5))) - t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (a <= -5.2) or not (a <= 0.52):
		tmp = (math.log(y) + (math.log(t) * a)) - t
	else:
		tmp = (math.log(y) + (math.log(z) + (math.log(t) * -0.5))) - t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((a <= -5.2) || !(a <= 0.52))
		tmp = Float64(Float64(log(y) + Float64(log(t) * a)) - t);
	else
		tmp = Float64(Float64(log(y) + Float64(log(z) + Float64(log(t) * -0.5))) - t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((a <= -5.2) || ~((a <= 0.52)))
		tmp = (log(y) + (log(t) * a)) - t;
	else
		tmp = (log(y) + (log(z) + (log(t) * -0.5))) - t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[a, -5.2], N[Not[LessEqual[a, 0.52]], $MachinePrecision]], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[z], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 0.52\right):\\
\;\;\;\;\left(\log y + \log t \cdot a\right) - t\\

\mathbf{else}:\\
\;\;\;\;\left(\log y + \left(\log z + \log t \cdot -0.5\right)\right) - t\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -5.20000000000000018 or 0.52000000000000002 < a

    1. Initial program 99.7%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 78.4%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around inf 78.0%

      \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative78.0%

        \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
    6. Simplified78.0%

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

    if -5.20000000000000018 < a < 0.52000000000000002

    1. Initial program 99.5%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 62.2%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around 0 61.3%

      \[\leadsto \left(\log y + \color{blue}{\left(\log z + -0.5 \cdot \log t\right)}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative61.3%

        \[\leadsto \left(\log y + \left(\log z + \color{blue}{\log t \cdot -0.5}\right)\right) - t \]
    6. Simplified61.3%

      \[\leadsto \left(\log y + \color{blue}{\left(\log z + \log t \cdot -0.5\right)}\right) - t \]
  3. Recombined 2 regimes into one program.
  4. Final simplification69.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 0.52\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log y + \left(\log z + \log t \cdot -0.5\right)\right) - t\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.6% accurate, 1.0× speedup?

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

\\
\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \log t \cdot \left(a - 0.5\right)
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Add Preprocessing
  3. Final simplification99.6%

    \[\leadsto \left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \log t \cdot \left(a - 0.5\right) \]
  4. Add Preprocessing

Alternative 5: 68.4% accurate, 1.0× speedup?

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

\\
\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0 70.2%

    \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
  4. Final simplification70.2%

    \[\leadsto \left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t \]
  5. Add Preprocessing

Alternative 6: 63.8% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq 2.7 \cdot 10^{+29} \lor \neg \left(t \leq 4.3 \cdot 10^{+101}\right) \land t \leq 3.75 \cdot 10^{+112}:\\ \;\;\;\;\log \left(x + y\right) + \log t \cdot a\\ \mathbf{else}:\\ \;\;\;\;-t\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= t 2.7e+29) (and (not (<= t 4.3e+101)) (<= t 3.75e+112)))
   (+ (log (+ x y)) (* (log t) a))
   (- t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((t <= 2.7e+29) || (!(t <= 4.3e+101) && (t <= 3.75e+112))) {
		tmp = log((x + y)) + (log(t) * a);
	} else {
		tmp = -t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if ((t <= 2.7d+29) .or. (.not. (t <= 4.3d+101)) .and. (t <= 3.75d+112)) then
        tmp = log((x + y)) + (log(t) * a)
    else
        tmp = -t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((t <= 2.7e+29) || (!(t <= 4.3e+101) && (t <= 3.75e+112))) {
		tmp = Math.log((x + y)) + (Math.log(t) * a);
	} else {
		tmp = -t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (t <= 2.7e+29) or (not (t <= 4.3e+101) and (t <= 3.75e+112)):
		tmp = math.log((x + y)) + (math.log(t) * a)
	else:
		tmp = -t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((t <= 2.7e+29) || (!(t <= 4.3e+101) && (t <= 3.75e+112)))
		tmp = Float64(log(Float64(x + y)) + Float64(log(t) * a));
	else
		tmp = Float64(-t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((t <= 2.7e+29) || (~((t <= 4.3e+101)) && (t <= 3.75e+112)))
		tmp = log((x + y)) + (log(t) * a);
	else
		tmp = -t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[t, 2.7e+29], And[N[Not[LessEqual[t, 4.3e+101]], $MachinePrecision], LessEqual[t, 3.75e+112]]], N[(N[Log[N[(x + y), $MachinePrecision]], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision], (-t)]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq 2.7 \cdot 10^{+29} \lor \neg \left(t \leq 4.3 \cdot 10^{+101}\right) \land t \leq 3.75 \cdot 10^{+112}:\\
\;\;\;\;\log \left(x + y\right) + \log t \cdot a\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < 2.7e29 or 4.3000000000000001e101 < t < 3.75e112

    1. Initial program 99.3%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.3%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.4%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.4%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in a around inf 55.7%

      \[\leadsto \log \left(x + y\right) + \color{blue}{a \cdot \log t} \]
    6. Step-by-step derivation
      1. *-commutative55.7%

        \[\leadsto \log \left(x + y\right) + \color{blue}{\log t \cdot a} \]
    7. Simplified55.7%

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

    if 2.7e29 < t < 4.3000000000000001e101 or 3.75e112 < t

    1. Initial program 99.9%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.9%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.9%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.9%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in t around inf 82.2%

      \[\leadsto \log \left(x + y\right) + \color{blue}{-1 \cdot t} \]
    6. Step-by-step derivation
      1. neg-mul-182.2%

        \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    7. Simplified82.2%

      \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    8. Taylor expanded in t around inf 82.2%

      \[\leadsto \color{blue}{-1 \cdot t} \]
    9. Step-by-step derivation
      1. neg-mul-182.2%

        \[\leadsto \color{blue}{-t} \]
    10. Simplified82.2%

      \[\leadsto \color{blue}{-t} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq 2.7 \cdot 10^{+29} \lor \neg \left(t \leq 4.3 \cdot 10^{+101}\right) \land t \leq 3.75 \cdot 10^{+112}:\\ \;\;\;\;\log \left(x + y\right) + \log t \cdot a\\ \mathbf{else}:\\ \;\;\;\;-t\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 73.9% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 1.15 \cdot 10^{-11}\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\log \left(z \cdot \left(x + y\right)\right) - \left(\log t \cdot 0.5 + t\right)\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= a -5.2) (not (<= a 1.15e-11)))
   (- (+ (log y) (* (log t) a)) t)
   (- (log (* z (+ x y))) (+ (* (log t) 0.5) t))))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 1.15e-11)) {
		tmp = (log(y) + (log(t) * a)) - t;
	} else {
		tmp = log((z * (x + y))) - ((log(t) * 0.5) + t);
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if ((a <= (-5.2d0)) .or. (.not. (a <= 1.15d-11))) then
        tmp = (log(y) + (log(t) * a)) - t
    else
        tmp = log((z * (x + y))) - ((log(t) * 0.5d0) + t)
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 1.15e-11)) {
		tmp = (Math.log(y) + (Math.log(t) * a)) - t;
	} else {
		tmp = Math.log((z * (x + y))) - ((Math.log(t) * 0.5) + t);
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (a <= -5.2) or not (a <= 1.15e-11):
		tmp = (math.log(y) + (math.log(t) * a)) - t
	else:
		tmp = math.log((z * (x + y))) - ((math.log(t) * 0.5) + t)
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((a <= -5.2) || !(a <= 1.15e-11))
		tmp = Float64(Float64(log(y) + Float64(log(t) * a)) - t);
	else
		tmp = Float64(log(Float64(z * Float64(x + y))) - Float64(Float64(log(t) * 0.5) + t));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((a <= -5.2) || ~((a <= 1.15e-11)))
		tmp = (log(y) + (log(t) * a)) - t;
	else
		tmp = log((z * (x + y))) - ((log(t) * 0.5) + t);
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[a, -5.2], N[Not[LessEqual[a, 1.15e-11]], $MachinePrecision]], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[Log[N[(z * N[(x + y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[(N[(N[Log[t], $MachinePrecision] * 0.5), $MachinePrecision] + t), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 1.15 \cdot 10^{-11}\right):\\
\;\;\;\;\left(\log y + \log t \cdot a\right) - t\\

\mathbf{else}:\\
\;\;\;\;\log \left(z \cdot \left(x + y\right)\right) - \left(\log t \cdot 0.5 + t\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -5.20000000000000018 or 1.15000000000000007e-11 < a

    1. Initial program 99.7%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 77.5%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around inf 76.5%

      \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative76.5%

        \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
    6. Simplified76.5%

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

    if -5.20000000000000018 < a < 1.15000000000000007e-11

    1. Initial program 99.5%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.5%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.5%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.5%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.5%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in a around 0 98.9%

      \[\leadsto \color{blue}{\left(\log z + \log \left(x + y\right)\right) - \left(t + 0.5 \cdot \log t\right)} \]
    6. Step-by-step derivation
      1. log-prod76.7%

        \[\leadsto \color{blue}{\log \left(z \cdot \left(x + y\right)\right)} - \left(t + 0.5 \cdot \log t\right) \]
      2. +-commutative76.7%

        \[\leadsto \log \left(z \cdot \color{blue}{\left(y + x\right)}\right) - \left(t + 0.5 \cdot \log t\right) \]
      3. *-commutative76.7%

        \[\leadsto \log \left(z \cdot \left(y + x\right)\right) - \left(t + \color{blue}{\log t \cdot 0.5}\right) \]
    7. Simplified76.7%

      \[\leadsto \color{blue}{\log \left(z \cdot \left(y + x\right)\right) - \left(t + \log t \cdot 0.5\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification76.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 1.15 \cdot 10^{-11}\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\log \left(z \cdot \left(x + y\right)\right) - \left(\log t \cdot 0.5 + t\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 61.0% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 8.2 \cdot 10^{-10}\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log t \cdot -0.5 + \log \left(y \cdot z\right)\right) - t\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= a -5.2) (not (<= a 8.2e-10)))
   (- (+ (log y) (* (log t) a)) t)
   (- (+ (* (log t) -0.5) (log (* y z))) t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 8.2e-10)) {
		tmp = (log(y) + (log(t) * a)) - t;
	} else {
		tmp = ((log(t) * -0.5) + log((y * z))) - t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if ((a <= (-5.2d0)) .or. (.not. (a <= 8.2d-10))) then
        tmp = (log(y) + (log(t) * a)) - t
    else
        tmp = ((log(t) * (-0.5d0)) + log((y * z))) - t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((a <= -5.2) || !(a <= 8.2e-10)) {
		tmp = (Math.log(y) + (Math.log(t) * a)) - t;
	} else {
		tmp = ((Math.log(t) * -0.5) + Math.log((y * z))) - t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (a <= -5.2) or not (a <= 8.2e-10):
		tmp = (math.log(y) + (math.log(t) * a)) - t
	else:
		tmp = ((math.log(t) * -0.5) + math.log((y * z))) - t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((a <= -5.2) || !(a <= 8.2e-10))
		tmp = Float64(Float64(log(y) + Float64(log(t) * a)) - t);
	else
		tmp = Float64(Float64(Float64(log(t) * -0.5) + log(Float64(y * z))) - t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((a <= -5.2) || ~((a <= 8.2e-10)))
		tmp = (log(y) + (log(t) * a)) - t;
	else
		tmp = ((log(t) * -0.5) + log((y * z))) - t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[a, -5.2], N[Not[LessEqual[a, 8.2e-10]], $MachinePrecision]], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[(N[(N[Log[t], $MachinePrecision] * -0.5), $MachinePrecision] + N[Log[N[(y * z), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 8.2 \cdot 10^{-10}\right):\\
\;\;\;\;\left(\log y + \log t \cdot a\right) - t\\

\mathbf{else}:\\
\;\;\;\;\left(\log t \cdot -0.5 + \log \left(y \cdot z\right)\right) - t\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -5.20000000000000018 or 8.1999999999999996e-10 < a

    1. Initial program 99.7%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 77.5%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around inf 76.5%

      \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative76.5%

        \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
    6. Simplified76.5%

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

    if -5.20000000000000018 < a < 8.1999999999999996e-10

    1. Initial program 99.5%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 62.6%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around 0 62.1%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + -0.5 \cdot \log t\right)\right)} - t \]
    5. Step-by-step derivation
      1. associate-+r+62.0%

        \[\leadsto \color{blue}{\left(\left(\log y + \log z\right) + -0.5 \cdot \log t\right)} - t \]
      2. log-prod48.4%

        \[\leadsto \left(\color{blue}{\log \left(y \cdot z\right)} + -0.5 \cdot \log t\right) - t \]
      3. +-commutative48.4%

        \[\leadsto \color{blue}{\left(-0.5 \cdot \log t + \log \left(y \cdot z\right)\right)} - t \]
      4. *-commutative48.4%

        \[\leadsto \left(\color{blue}{\log t \cdot -0.5} + \log \left(y \cdot z\right)\right) - t \]
      5. *-commutative48.4%

        \[\leadsto \left(\log t \cdot -0.5 + \log \color{blue}{\left(z \cdot y\right)}\right) - t \]
    6. Simplified48.4%

      \[\leadsto \color{blue}{\left(\log t \cdot -0.5 + \log \left(z \cdot y\right)\right)} - t \]
  3. Recombined 2 regimes into one program.
  4. Final simplification62.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -5.2 \lor \neg \left(a \leq 8.2 \cdot 10^{-10}\right):\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \mathbf{else}:\\ \;\;\;\;\left(\log t \cdot -0.5 + \log \left(y \cdot z\right)\right) - t\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 60.9% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq 34:\\ \;\;\;\;\log \left(y \cdot z\right) + \log t \cdot \left(a - 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (<= t 34.0)
   (+ (log (* y z)) (* (log t) (- a 0.5)))
   (- (+ (log y) (* (log t) a)) t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if (t <= 34.0) {
		tmp = log((y * z)) + (log(t) * (a - 0.5));
	} else {
		tmp = (log(y) + (log(t) * a)) - t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if (t <= 34.0d0) then
        tmp = log((y * z)) + (log(t) * (a - 0.5d0))
    else
        tmp = (log(y) + (log(t) * a)) - t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if (t <= 34.0) {
		tmp = Math.log((y * z)) + (Math.log(t) * (a - 0.5));
	} else {
		tmp = (Math.log(y) + (Math.log(t) * a)) - t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if t <= 34.0:
		tmp = math.log((y * z)) + (math.log(t) * (a - 0.5))
	else:
		tmp = (math.log(y) + (math.log(t) * a)) - t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if (t <= 34.0)
		tmp = Float64(log(Float64(y * z)) + Float64(log(t) * Float64(a - 0.5)));
	else
		tmp = Float64(Float64(log(y) + Float64(log(t) * a)) - t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if (t <= 34.0)
		tmp = log((y * z)) + (log(t) * (a - 0.5));
	else
		tmp = (log(y) + (log(t) * a)) - t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[LessEqual[t, 34.0], N[(N[Log[N[(y * z), $MachinePrecision]], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * N[(a - 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[Log[y], $MachinePrecision] + N[(N[Log[t], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq 34:\\
\;\;\;\;\log \left(y \cdot z\right) + \log t \cdot \left(a - 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\log y + \log t \cdot a\right) - t\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < 34

    1. Initial program 99.3%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.3%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.4%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.4%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in t around 0 97.1%

      \[\leadsto \color{blue}{\left(\log z + \log \left(x + y\right)\right) - \log t \cdot \left(0.5 - a\right)} \]
    6. Step-by-step derivation
      1. log-prod71.6%

        \[\leadsto \color{blue}{\log \left(z \cdot \left(x + y\right)\right)} - \log t \cdot \left(0.5 - a\right) \]
      2. +-commutative71.6%

        \[\leadsto \log \left(z \cdot \color{blue}{\left(y + x\right)}\right) - \log t \cdot \left(0.5 - a\right) \]
    7. Simplified71.6%

      \[\leadsto \color{blue}{\log \left(z \cdot \left(y + x\right)\right) - \log t \cdot \left(0.5 - a\right)} \]
    8. Taylor expanded in y around inf 60.4%

      \[\leadsto \color{blue}{\left(\log z + -1 \cdot \log \left(\frac{1}{y}\right)\right)} - \log t \cdot \left(0.5 - a\right) \]
    9. Step-by-step derivation
      1. mul-1-neg60.4%

        \[\leadsto \left(\log z + \color{blue}{\left(-\log \left(\frac{1}{y}\right)\right)}\right) - \log t \cdot \left(0.5 - a\right) \]
      2. log-rec60.4%

        \[\leadsto \left(\log z + \left(-\color{blue}{\left(-\log y\right)}\right)\right) - \log t \cdot \left(0.5 - a\right) \]
      3. remove-double-neg60.4%

        \[\leadsto \left(\log z + \color{blue}{\log y}\right) - \log t \cdot \left(0.5 - a\right) \]
      4. log-prod48.8%

        \[\leadsto \color{blue}{\log \left(z \cdot y\right)} - \log t \cdot \left(0.5 - a\right) \]
    10. Simplified48.8%

      \[\leadsto \color{blue}{\log \left(z \cdot y\right)} - \log t \cdot \left(0.5 - a\right) \]

    if 34 < t

    1. Initial program 99.9%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 77.7%

      \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
    4. Taylor expanded in a around inf 76.9%

      \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
    5. Step-by-step derivation
      1. *-commutative76.9%

        \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
    6. Simplified76.9%

      \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
  3. Recombined 2 regimes into one program.
  4. Final simplification63.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq 34:\\ \;\;\;\;\log \left(y \cdot z\right) + \log t \cdot \left(a - 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\log y + \log t \cdot a\right) - t\\ \end{array} \]
  5. Add Preprocessing

Alternative 10: 57.3% accurate, 1.5× speedup?

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

\\
\left(\log y + \log t \cdot a\right) - t
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0 70.2%

    \[\leadsto \color{blue}{\left(\log y + \left(\log z + \log t \cdot \left(a - 0.5\right)\right)\right) - t} \]
  4. Taylor expanded in a around inf 58.0%

    \[\leadsto \left(\log y + \color{blue}{a \cdot \log t}\right) - t \]
  5. Step-by-step derivation
    1. *-commutative58.0%

      \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
  6. Simplified58.0%

    \[\leadsto \left(\log y + \color{blue}{\log t \cdot a}\right) - t \]
  7. Final simplification58.0%

    \[\leadsto \left(\log y + \log t \cdot a\right) - t \]
  8. Add Preprocessing

Alternative 11: 30.9% accurate, 1.5× speedup?

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

\\
\left(\log z + \log y\right) - t
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Step-by-step derivation
    1. associate-+l-99.6%

      \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
    2. associate--l+99.6%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
    3. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
    4. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
    5. *-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
    6. distribute-rgt-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
    7. fma-udef99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
    8. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
    9. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
    10. distribute-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
    11. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
    12. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
    13. unsub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in t around inf 43.0%

    \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{t}\right) \]
  6. Taylor expanded in x around 0 31.9%

    \[\leadsto \color{blue}{\left(\log y + \log z\right) - t} \]
  7. Final simplification31.9%

    \[\leadsto \left(\log z + \log y\right) - t \]
  8. Add Preprocessing

Alternative 12: 41.3% accurate, 2.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq 0.195:\\ \;\;\;\;\log \left(x + y\right)\\ \mathbf{else}:\\ \;\;\;\;-t\\ \end{array} \end{array} \]
(FPCore (x y z t a) :precision binary64 (if (<= t 0.195) (log (+ x y)) (- t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if (t <= 0.195) {
		tmp = log((x + y));
	} else {
		tmp = -t;
	}
	return tmp;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8) :: tmp
    if (t <= 0.195d0) then
        tmp = log((x + y))
    else
        tmp = -t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if (t <= 0.195) {
		tmp = Math.log((x + y));
	} else {
		tmp = -t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if t <= 0.195:
		tmp = math.log((x + y))
	else:
		tmp = -t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if (t <= 0.195)
		tmp = log(Float64(x + y));
	else
		tmp = Float64(-t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if (t <= 0.195)
		tmp = log((x + y));
	else
		tmp = -t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[LessEqual[t, 0.195], N[Log[N[(x + y), $MachinePrecision]], $MachinePrecision], (-t)]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq 0.195:\\
\;\;\;\;\log \left(x + y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < 0.19500000000000001

    1. Initial program 99.3%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.3%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.4%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.4%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.4%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in t around inf 9.8%

      \[\leadsto \log \left(x + y\right) + \color{blue}{-1 \cdot t} \]
    6. Step-by-step derivation
      1. neg-mul-19.8%

        \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    7. Simplified9.8%

      \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    8. Taylor expanded in t around 0 9.8%

      \[\leadsto \color{blue}{\log \left(x + y\right)} \]
    9. Step-by-step derivation
      1. +-commutative9.8%

        \[\leadsto \log \color{blue}{\left(y + x\right)} \]
    10. Simplified9.8%

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

    if 0.19500000000000001 < t

    1. Initial program 99.9%

      \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
    2. Step-by-step derivation
      1. associate-+l-99.9%

        \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
      2. associate--l+99.8%

        \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
      3. sub-neg99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
      4. +-commutative99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
      5. *-commutative99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
      6. distribute-rgt-neg-in99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
      7. fma-udef99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
      8. sub-neg99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
      9. +-commutative99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
      10. distribute-neg-in99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
      11. metadata-eval99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
      12. metadata-eval99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
      13. unsub-neg99.8%

        \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
    3. Simplified99.8%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in t around inf 72.5%

      \[\leadsto \log \left(x + y\right) + \color{blue}{-1 \cdot t} \]
    6. Step-by-step derivation
      1. neg-mul-172.5%

        \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    7. Simplified72.5%

      \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
    8. Taylor expanded in t around inf 72.6%

      \[\leadsto \color{blue}{-1 \cdot t} \]
    9. Step-by-step derivation
      1. neg-mul-172.6%

        \[\leadsto \color{blue}{-t} \]
    10. Simplified72.6%

      \[\leadsto \color{blue}{-t} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification42.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq 0.195:\\ \;\;\;\;\log \left(x + y\right)\\ \mathbf{else}:\\ \;\;\;\;-t\\ \end{array} \]
  5. Add Preprocessing

Alternative 13: 30.4% accurate, 3.0× speedup?

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

\\
\log y - t
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Step-by-step derivation
    1. associate-+l-99.6%

      \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
    2. associate--l+99.6%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
    3. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
    4. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
    5. *-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
    6. distribute-rgt-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
    7. fma-udef99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
    8. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
    9. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
    10. distribute-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
    11. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
    12. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
    13. unsub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in t around inf 42.1%

    \[\leadsto \log \left(x + y\right) + \color{blue}{-1 \cdot t} \]
  6. Step-by-step derivation
    1. neg-mul-142.1%

      \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
  7. Simplified42.1%

    \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
  8. Taylor expanded in x around 0 31.4%

    \[\leadsto \color{blue}{\log y - t} \]
  9. Final simplification31.4%

    \[\leadsto \log y - t \]
  10. Add Preprocessing

Alternative 14: 38.0% accurate, 156.5× speedup?

\[\begin{array}{l} \\ -t \end{array} \]
(FPCore (x y z t a) :precision binary64 (- t))
double code(double x, double y, double z, double t, double a) {
	return -t;
}
real(8) function code(x, y, z, t, a)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    code = -t
end function
public static double code(double x, double y, double z, double t, double a) {
	return -t;
}
def code(x, y, z, t, a):
	return -t
function code(x, y, z, t, a)
	return Float64(-t)
end
function tmp = code(x, y, z, t, a)
	tmp = -t;
end
code[x_, y_, z_, t_, a_] := (-t)
\begin{array}{l}

\\
-t
\end{array}
Derivation
  1. Initial program 99.6%

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t \]
  2. Step-by-step derivation
    1. associate-+l-99.6%

      \[\leadsto \color{blue}{\left(\log \left(x + y\right) + \log z\right) - \left(t - \left(a - 0.5\right) \cdot \log t\right)} \]
    2. associate--l+99.6%

      \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \left(t - \left(a - 0.5\right) \cdot \log t\right)\right)} \]
    3. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(t + \left(-\left(a - 0.5\right) \cdot \log t\right)\right)}\right) \]
    4. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\left(\left(-\left(a - 0.5\right) \cdot \log t\right) + t\right)}\right) \]
    5. *-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\left(-\color{blue}{\log t \cdot \left(a - 0.5\right)}\right) + t\right)\right) \]
    6. distribute-rgt-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \left(\color{blue}{\log t \cdot \left(-\left(a - 0.5\right)\right)} + t\right)\right) \]
    7. fma-udef99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \color{blue}{\mathsf{fma}\left(\log t, -\left(a - 0.5\right), t\right)}\right) \]
    8. sub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(a + \left(-0.5\right)\right)}, t\right)\right) \]
    9. +-commutative99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, -\color{blue}{\left(\left(-0.5\right) + a\right)}, t\right)\right) \]
    10. distribute-neg-in99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{\left(-\left(-0.5\right)\right) + \left(-a\right)}, t\right)\right) \]
    11. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \left(-\color{blue}{-0.5}\right) + \left(-a\right), t\right)\right) \]
    12. metadata-eval99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5} + \left(-a\right), t\right)\right) \]
    13. unsub-neg99.6%

      \[\leadsto \log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, \color{blue}{0.5 - a}, t\right)\right) \]
  3. Simplified99.6%

    \[\leadsto \color{blue}{\log \left(x + y\right) + \left(\log z - \mathsf{fma}\left(\log t, 0.5 - a, t\right)\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in t around inf 42.1%

    \[\leadsto \log \left(x + y\right) + \color{blue}{-1 \cdot t} \]
  6. Step-by-step derivation
    1. neg-mul-142.1%

      \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
  7. Simplified42.1%

    \[\leadsto \log \left(x + y\right) + \color{blue}{\left(-t\right)} \]
  8. Taylor expanded in t around inf 38.8%

    \[\leadsto \color{blue}{-1 \cdot t} \]
  9. Step-by-step derivation
    1. neg-mul-138.8%

      \[\leadsto \color{blue}{-t} \]
  10. Simplified38.8%

    \[\leadsto \color{blue}{-t} \]
  11. Final simplification38.8%

    \[\leadsto -t \]
  12. Add Preprocessing

Developer target: 99.6% accurate, 1.0× speedup?

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

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

Reproduce

?
herbie shell --seed 2024021 
(FPCore (x y z t a)
  :name "Numeric.SpecFunctions:logGammaL from math-functions-0.1.5.2"
  :precision binary64

  :herbie-target
  (+ (log (+ x y)) (+ (- (log z) t) (* (- a 0.5) (log t))))

  (+ (- (+ (log (+ x y)) (log z)) t) (* (- a 0.5) (log t))))