Numeric.AD.Rank1.Halley:findZero from ad-4.2.4

Percentage Accurate: 82.0% → 98.2%
Time: 6.7s
Alternatives: 6
Speedup: 1.5×

Specification

?
\[\begin{array}{l} \\ x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (- x (/ (* (* y 2.0) z) (- (* (* z 2.0) z) (* y t)))))
double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = x - (((y * 2.0d0) * z) / (((z * 2.0d0) * z) - (y * t)))
end function
public static double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
def code(x, y, z, t):
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)))
function code(x, y, z, t)
	return Float64(x - Float64(Float64(Float64(y * 2.0) * z) / Float64(Float64(Float64(z * 2.0) * z) - Float64(y * t))))
end
function tmp = code(x, y, z, t)
	tmp = x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
end
code[x_, y_, z_, t_] := N[(x - N[(N[(N[(y * 2.0), $MachinePrecision] * z), $MachinePrecision] / N[(N[(N[(z * 2.0), $MachinePrecision] * z), $MachinePrecision] - N[(y * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot 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 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: 82.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (- x (/ (* (* y 2.0) z) (- (* (* z 2.0) z) (* y t)))))
double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = x - (((y * 2.0d0) * z) / (((z * 2.0d0) * z) - (y * t)))
end function
public static double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
def code(x, y, z, t):
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)))
function code(x, y, z, t)
	return Float64(x - Float64(Float64(Float64(y * 2.0) * z) / Float64(Float64(Float64(z * 2.0) * z) - Float64(y * t))))
end
function tmp = code(x, y, z, t)
	tmp = x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
end
code[x_, y_, z_, t_] := N[(x - N[(N[(N[(y * 2.0), $MachinePrecision] * z), $MachinePrecision] / N[(N[(N[(z * 2.0), $MachinePrecision] * z), $MachinePrecision] - N[(y * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}
\end{array}

Alternative 1: 98.2% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\frac{y}{z \cdot -2 + y \cdot \frac{t}{z}}, 2, x\right) \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (fma (/ y (+ (* z -2.0) (* y (/ t z)))) 2.0 x))
double code(double x, double y, double z, double t) {
	return fma((y / ((z * -2.0) + (y * (t / z)))), 2.0, x);
}
function code(x, y, z, t)
	return fma(Float64(y / Float64(Float64(z * -2.0) + Float64(y * Float64(t / z)))), 2.0, x)
end
code[x_, y_, z_, t_] := N[(N[(y / N[(N[(z * -2.0), $MachinePrecision] + N[(y * N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 2.0 + x), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\frac{y}{z \cdot -2 + y \cdot \frac{t}{z}}, 2, x\right)
\end{array}
Derivation
  1. Initial program 81.7%

    \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
  2. Step-by-step derivation
    1. sub-neg81.7%

      \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
    2. +-commutative81.7%

      \[\leadsto \color{blue}{\left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right) + x} \]
    3. distribute-neg-frac81.7%

      \[\leadsto \color{blue}{\frac{-\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}} + x \]
    4. distribute-rgt-neg-out81.7%

      \[\leadsto \frac{\color{blue}{\left(y \cdot 2\right) \cdot \left(-z\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} + x \]
    5. remove-double-neg81.7%

      \[\leadsto \frac{\left(y \cdot 2\right) \cdot \left(-z\right)}{\color{blue}{\left(-\left(-\left(z \cdot 2\right) \cdot z\right)\right)} - y \cdot t} + x \]
    6. distribute-rgt-neg-in81.7%

      \[\leadsto \frac{\left(y \cdot 2\right) \cdot \left(-z\right)}{\left(-\color{blue}{\left(z \cdot 2\right) \cdot \left(-z\right)}\right) - y \cdot t} + x \]
    7. distribute-lft-neg-out81.7%

      \[\leadsto \frac{\left(y \cdot 2\right) \cdot \left(-z\right)}{\color{blue}{\left(-z \cdot 2\right) \cdot \left(-z\right)} - y \cdot t} + x \]
    8. distribute-lft-neg-out81.7%

      \[\leadsto \frac{\left(y \cdot 2\right) \cdot \left(-z\right)}{\color{blue}{\left(\left(-z\right) \cdot 2\right)} \cdot \left(-z\right) - y \cdot t} + x \]
    9. associate-/l*90.5%

      \[\leadsto \color{blue}{\frac{y \cdot 2}{\frac{\left(\left(-z\right) \cdot 2\right) \cdot \left(-z\right) - y \cdot t}{-z}}} + x \]
    10. associate-*l/90.5%

      \[\leadsto \color{blue}{\frac{y}{\frac{\left(\left(-z\right) \cdot 2\right) \cdot \left(-z\right) - y \cdot t}{-z}} \cdot 2} + x \]
    11. fma-def90.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{y}{\frac{\left(\left(-z\right) \cdot 2\right) \cdot \left(-z\right) - y \cdot t}{-z}}, 2, x\right)} \]
  3. Simplified98.9%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{y}{z \cdot -2 + \frac{t}{z} \cdot y}, 2, x\right)} \]
  4. Final simplification98.9%

    \[\leadsto \mathsf{fma}\left(\frac{y}{z \cdot -2 + y \cdot \frac{t}{z}}, 2, x\right) \]

Alternative 2: 93.9% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := z \cdot \left(z \cdot 2\right) - y \cdot t\\ \mathbf{if}\;\frac{z \cdot \left(y \cdot 2\right)}{t_1} \leq 2 \cdot 10^{+154}:\\ \;\;\;\;x - \frac{y \cdot 2}{\frac{t_1}{z}}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{y}{z}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (let* ((t_1 (- (* z (* z 2.0)) (* y t))))
   (if (<= (/ (* z (* y 2.0)) t_1) 2e+154)
     (- x (/ (* y 2.0) (/ t_1 z)))
     (- x (/ y z)))))
double code(double x, double y, double z, double t) {
	double t_1 = (z * (z * 2.0)) - (y * t);
	double tmp;
	if (((z * (y * 2.0)) / t_1) <= 2e+154) {
		tmp = x - ((y * 2.0) / (t_1 / z));
	} else {
		tmp = x - (y / z);
	}
	return tmp;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = (z * (z * 2.0d0)) - (y * t)
    if (((z * (y * 2.0d0)) / t_1) <= 2d+154) then
        tmp = x - ((y * 2.0d0) / (t_1 / z))
    else
        tmp = x - (y / z)
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double t_1 = (z * (z * 2.0)) - (y * t);
	double tmp;
	if (((z * (y * 2.0)) / t_1) <= 2e+154) {
		tmp = x - ((y * 2.0) / (t_1 / z));
	} else {
		tmp = x - (y / z);
	}
	return tmp;
}
def code(x, y, z, t):
	t_1 = (z * (z * 2.0)) - (y * t)
	tmp = 0
	if ((z * (y * 2.0)) / t_1) <= 2e+154:
		tmp = x - ((y * 2.0) / (t_1 / z))
	else:
		tmp = x - (y / z)
	return tmp
function code(x, y, z, t)
	t_1 = Float64(Float64(z * Float64(z * 2.0)) - Float64(y * t))
	tmp = 0.0
	if (Float64(Float64(z * Float64(y * 2.0)) / t_1) <= 2e+154)
		tmp = Float64(x - Float64(Float64(y * 2.0) / Float64(t_1 / z)));
	else
		tmp = Float64(x - Float64(y / z));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	t_1 = (z * (z * 2.0)) - (y * t);
	tmp = 0.0;
	if (((z * (y * 2.0)) / t_1) <= 2e+154)
		tmp = x - ((y * 2.0) / (t_1 / z));
	else
		tmp = x - (y / z);
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(z * N[(z * 2.0), $MachinePrecision]), $MachinePrecision] - N[(y * t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(z * N[(y * 2.0), $MachinePrecision]), $MachinePrecision] / t$95$1), $MachinePrecision], 2e+154], N[(x - N[(N[(y * 2.0), $MachinePrecision] / N[(t$95$1 / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := z \cdot \left(z \cdot 2\right) - y \cdot t\\
\mathbf{if}\;\frac{z \cdot \left(y \cdot 2\right)}{t_1} \leq 2 \cdot 10^{+154}:\\
\;\;\;\;x - \frac{y \cdot 2}{\frac{t_1}{z}}\\

\mathbf{else}:\\
\;\;\;\;x - \frac{y}{z}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 (*.f64 y 2) z) (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t))) < 2.00000000000000007e154

    1. Initial program 95.9%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. associate-/l*98.1%

        \[\leadsto x - \color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      2. associate-*l*98.1%

        \[\leadsto x - \frac{y \cdot 2}{\frac{\color{blue}{z \cdot \left(2 \cdot z\right)} - y \cdot t}{z}} \]
    3. Simplified98.1%

      \[\leadsto \color{blue}{x - \frac{y \cdot 2}{\frac{z \cdot \left(2 \cdot z\right) - y \cdot t}{z}}} \]

    if 2.00000000000000007e154 < (/.f64 (*.f64 (*.f64 y 2) z) (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)))

    1. Initial program 2.6%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg2.6%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*48.1%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac48.1%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out48.1%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/48.1%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out48.1%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in48.1%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval48.1%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative48.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*48.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg48.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified48.1%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in y around 0 82.7%

      \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
    5. Step-by-step derivation
      1. mul-1-neg82.7%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      2. sub-neg82.7%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified82.7%

      \[\leadsto \color{blue}{x - \frac{y}{z}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification95.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{z \cdot \left(y \cdot 2\right)}{z \cdot \left(z \cdot 2\right) - y \cdot t} \leq 2 \cdot 10^{+154}:\\ \;\;\;\;x - \frac{y \cdot 2}{\frac{z \cdot \left(z \cdot 2\right) - y \cdot t}{z}}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{y}{z}\\ \end{array} \]

Alternative 3: 89.1% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -2.5 \cdot 10^{+39} \lor \neg \left(z \leq 0.0035\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \frac{2}{t}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -2.5e+39) (not (<= z 0.0035)))
   (- x (/ y z))
   (+ x (* z (/ 2.0 t)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -2.5e+39) || !(z <= 0.0035)) {
		tmp = x - (y / z);
	} else {
		tmp = x + (z * (2.0 / t));
	}
	return tmp;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8) :: tmp
    if ((z <= (-2.5d+39)) .or. (.not. (z <= 0.0035d0))) then
        tmp = x - (y / z)
    else
        tmp = x + (z * (2.0d0 / t))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -2.5e+39) || !(z <= 0.0035)) {
		tmp = x - (y / z);
	} else {
		tmp = x + (z * (2.0 / t));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -2.5e+39) or not (z <= 0.0035):
		tmp = x - (y / z)
	else:
		tmp = x + (z * (2.0 / t))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -2.5e+39) || !(z <= 0.0035))
		tmp = Float64(x - Float64(y / z));
	else
		tmp = Float64(x + Float64(z * Float64(2.0 / t)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z <= -2.5e+39) || ~((z <= 0.0035)))
		tmp = x - (y / z);
	else
		tmp = x + (z * (2.0 / t));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -2.5e+39], N[Not[LessEqual[z, 0.0035]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], N[(x + N[(z * N[(2.0 / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -2.5 \cdot 10^{+39} \lor \neg \left(z \leq 0.0035\right):\\
\;\;\;\;x - \frac{y}{z}\\

\mathbf{else}:\\
\;\;\;\;x + z \cdot \frac{2}{t}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -2.50000000000000008e39 or 0.00350000000000000007 < z

    1. Initial program 69.7%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg69.7%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*88.0%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac88.0%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out88.0%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/87.6%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out87.6%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in87.6%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval87.6%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified87.6%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in y around 0 92.7%

      \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
    5. Step-by-step derivation
      1. mul-1-neg92.7%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      2. sub-neg92.7%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified92.7%

      \[\leadsto \color{blue}{x - \frac{y}{z}} \]

    if -2.50000000000000008e39 < z < 0.00350000000000000007

    1. Initial program 90.1%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg90.1%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*92.2%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac92.2%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out92.2%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/93.4%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out93.4%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in93.4%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval93.4%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative93.4%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*93.4%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg93.4%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified93.4%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in y around inf 86.0%

      \[\leadsto x + \color{blue}{\frac{2}{t}} \cdot z \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -2.5 \cdot 10^{+39} \lor \neg \left(z \leq 0.0035\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \frac{2}{t}\\ \end{array} \]

Alternative 4: 89.2% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -3.6 \cdot 10^{+39} \lor \neg \left(z \leq 0.0031\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{z \cdot -2}{t}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -3.6e+39) (not (<= z 0.0031)))
   (- x (/ y z))
   (- x (/ (* z -2.0) t))))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -3.6e+39) || !(z <= 0.0031)) {
		tmp = x - (y / z);
	} else {
		tmp = x - ((z * -2.0) / t);
	}
	return tmp;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8) :: tmp
    if ((z <= (-3.6d+39)) .or. (.not. (z <= 0.0031d0))) then
        tmp = x - (y / z)
    else
        tmp = x - ((z * (-2.0d0)) / t)
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -3.6e+39) || !(z <= 0.0031)) {
		tmp = x - (y / z);
	} else {
		tmp = x - ((z * -2.0) / t);
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -3.6e+39) or not (z <= 0.0031):
		tmp = x - (y / z)
	else:
		tmp = x - ((z * -2.0) / t)
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -3.6e+39) || !(z <= 0.0031))
		tmp = Float64(x - Float64(y / z));
	else
		tmp = Float64(x - Float64(Float64(z * -2.0) / t));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z <= -3.6e+39) || ~((z <= 0.0031)))
		tmp = x - (y / z);
	else
		tmp = x - ((z * -2.0) / t);
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -3.6e+39], N[Not[LessEqual[z, 0.0031]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], N[(x - N[(N[(z * -2.0), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -3.6 \cdot 10^{+39} \lor \neg \left(z \leq 0.0031\right):\\
\;\;\;\;x - \frac{y}{z}\\

\mathbf{else}:\\
\;\;\;\;x - \frac{z \cdot -2}{t}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -3.59999999999999984e39 or 0.00309999999999999989 < z

    1. Initial program 69.7%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg69.7%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*88.0%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac88.0%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out88.0%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/87.6%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out87.6%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in87.6%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval87.6%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg87.6%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified87.6%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in y around 0 92.7%

      \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
    5. Step-by-step derivation
      1. mul-1-neg92.7%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      2. sub-neg92.7%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified92.7%

      \[\leadsto \color{blue}{x - \frac{y}{z}} \]

    if -3.59999999999999984e39 < z < 0.00309999999999999989

    1. Initial program 90.1%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. associate-/l*92.2%

        \[\leadsto x - \color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      2. associate-*l*92.2%

        \[\leadsto x - \frac{y \cdot 2}{\frac{\color{blue}{z \cdot \left(2 \cdot z\right)} - y \cdot t}{z}} \]
    3. Simplified92.2%

      \[\leadsto \color{blue}{x - \frac{y \cdot 2}{\frac{z \cdot \left(2 \cdot z\right) - y \cdot t}{z}}} \]
    4. Taylor expanded in y around inf 86.0%

      \[\leadsto x - \color{blue}{-2 \cdot \frac{z}{t}} \]
    5. Step-by-step derivation
      1. associate-*r/86.0%

        \[\leadsto x - \color{blue}{\frac{-2 \cdot z}{t}} \]
      2. *-commutative86.0%

        \[\leadsto x - \frac{\color{blue}{z \cdot -2}}{t} \]
    6. Simplified86.0%

      \[\leadsto x - \color{blue}{\frac{z \cdot -2}{t}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -3.6 \cdot 10^{+39} \lor \neg \left(z \leq 0.0031\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{z \cdot -2}{t}\\ \end{array} \]

Alternative 5: 81.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -4.3 \cdot 10^{+40} \lor \neg \left(z \leq 3.2 \cdot 10^{+136}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -4.3e+40) (not (<= z 3.2e+136))) (- x (/ y z)) x))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -4.3e+40) || !(z <= 3.2e+136)) {
		tmp = x - (y / z);
	} else {
		tmp = x;
	}
	return tmp;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8) :: tmp
    if ((z <= (-4.3d+40)) .or. (.not. (z <= 3.2d+136))) then
        tmp = x - (y / z)
    else
        tmp = x
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -4.3e+40) || !(z <= 3.2e+136)) {
		tmp = x - (y / z);
	} else {
		tmp = x;
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -4.3e+40) or not (z <= 3.2e+136):
		tmp = x - (y / z)
	else:
		tmp = x
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -4.3e+40) || !(z <= 3.2e+136))
		tmp = Float64(x - Float64(y / z));
	else
		tmp = x;
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z <= -4.3e+40) || ~((z <= 3.2e+136)))
		tmp = x - (y / z);
	else
		tmp = x;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -4.3e+40], N[Not[LessEqual[z, 3.2e+136]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -4.3 \cdot 10^{+40} \lor \neg \left(z \leq 3.2 \cdot 10^{+136}\right):\\
\;\;\;\;x - \frac{y}{z}\\

\mathbf{else}:\\
\;\;\;\;x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -4.3000000000000002e40 or 3.19999999999999988e136 < z

    1. Initial program 65.5%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg65.5%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*85.5%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac85.5%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out85.5%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/85.1%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out85.1%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in85.1%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval85.1%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative85.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*85.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg85.1%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified85.1%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in y around 0 95.3%

      \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
    5. Step-by-step derivation
      1. mul-1-neg95.3%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      2. sub-neg95.3%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified95.3%

      \[\leadsto \color{blue}{x - \frac{y}{z}} \]

    if -4.3000000000000002e40 < z < 3.19999999999999988e136

    1. Initial program 89.3%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg89.3%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*92.8%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. distribute-neg-frac92.8%

        \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. distribute-lft-neg-out92.8%

        \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      5. associate-/r/93.8%

        \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
      6. distribute-lft-neg-out93.8%

        \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      7. distribute-rgt-neg-in93.8%

        \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      8. metadata-eval93.8%

        \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
      9. *-commutative93.8%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
      10. associate-*l*93.8%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
      11. fma-neg93.8%

        \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
    3. Simplified93.8%

      \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
    4. Taylor expanded in x around inf 80.9%

      \[\leadsto \color{blue}{x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification85.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -4.3 \cdot 10^{+40} \lor \neg \left(z \leq 3.2 \cdot 10^{+136}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \]

Alternative 6: 74.9% accurate, 17.0× speedup?

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

\\
x
\end{array}
Derivation
  1. Initial program 81.7%

    \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
  2. Step-by-step derivation
    1. sub-neg81.7%

      \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
    2. associate-/l*90.5%

      \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
    3. distribute-neg-frac90.5%

      \[\leadsto x + \color{blue}{\frac{-y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
    4. distribute-lft-neg-out90.5%

      \[\leadsto x + \frac{\color{blue}{\left(-y\right) \cdot 2}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
    5. associate-/r/91.0%

      \[\leadsto x + \color{blue}{\frac{\left(-y\right) \cdot 2}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z} \]
    6. distribute-lft-neg-out91.0%

      \[\leadsto x + \frac{\color{blue}{-y \cdot 2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
    7. distribute-rgt-neg-in91.0%

      \[\leadsto x + \frac{\color{blue}{y \cdot \left(-2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
    8. metadata-eval91.0%

      \[\leadsto x + \frac{y \cdot \color{blue}{-2}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \cdot z \]
    9. *-commutative91.0%

      \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\left(2 \cdot z\right)} \cdot z - y \cdot t} \cdot z \]
    10. associate-*l*91.0%

      \[\leadsto x + \frac{y \cdot -2}{\color{blue}{2 \cdot \left(z \cdot z\right)} - y \cdot t} \cdot z \]
    11. fma-neg91.0%

      \[\leadsto x + \frac{y \cdot -2}{\color{blue}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)}} \cdot z \]
  3. Simplified91.0%

    \[\leadsto \color{blue}{x + \frac{y \cdot -2}{\mathsf{fma}\left(2, z \cdot z, -y \cdot t\right)} \cdot z} \]
  4. Taylor expanded in x around inf 80.5%

    \[\leadsto \color{blue}{x} \]
  5. Final simplification80.5%

    \[\leadsto x \]

Developer target: 99.9% accurate, 1.3× speedup?

\[\begin{array}{l} \\ x - \frac{1}{\frac{z}{y} - \frac{\frac{t}{2}}{z}} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (- x (/ 1.0 (- (/ z y) (/ (/ t 2.0) z)))))
double code(double x, double y, double z, double t) {
	return x - (1.0 / ((z / y) - ((t / 2.0) / z)));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = x - (1.0d0 / ((z / y) - ((t / 2.0d0) / z)))
end function
public static double code(double x, double y, double z, double t) {
	return x - (1.0 / ((z / y) - ((t / 2.0) / z)));
}
def code(x, y, z, t):
	return x - (1.0 / ((z / y) - ((t / 2.0) / z)))
function code(x, y, z, t)
	return Float64(x - Float64(1.0 / Float64(Float64(z / y) - Float64(Float64(t / 2.0) / z))))
end
function tmp = code(x, y, z, t)
	tmp = x - (1.0 / ((z / y) - ((t / 2.0) / z)));
end
code[x_, y_, z_, t_] := N[(x - N[(1.0 / N[(N[(z / y), $MachinePrecision] - N[(N[(t / 2.0), $MachinePrecision] / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x - \frac{1}{\frac{z}{y} - \frac{\frac{t}{2}}{z}}
\end{array}

Reproduce

?
herbie shell --seed 2023297 
(FPCore (x y z t)
  :name "Numeric.AD.Rank1.Halley:findZero from ad-4.2.4"
  :precision binary64

  :herbie-target
  (- x (/ 1.0 (- (/ z y) (/ (/ t 2.0) z))))

  (- x (/ (* (* y 2.0) z) (- (* (* z 2.0) z) (* y t)))))