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

Percentage Accurate: 82.0% → 99.8%
Time: 6.5s
Alternatives: 5
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 5 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: 99.8% accurate, 1.3× speedup?

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

\\
x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}
\end{array}
Derivation
  1. Initial program 85.3%

    \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
  2. Step-by-step derivation
    1. sub-neg85.3%

      \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
    2. associate-/l*92.6%

      \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
    3. *-commutative92.6%

      \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
    4. associate-/l*92.5%

      \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
    5. distribute-neg-frac92.5%

      \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
    6. metadata-eval92.5%

      \[\leadsto x + \frac{\color{blue}{-2}}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}} \]
    7. associate-/l/85.3%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
    8. div-sub76.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
    9. times-frac92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
    10. *-inverses92.6%

      \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
    11. *-rgt-identity92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
    12. *-commutative92.6%

      \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
    13. associate-*l/92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
    14. *-commutative92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
    15. times-frac99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
    16. *-inverses99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
    17. *-lft-identity99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
  3. Simplified99.9%

    \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
  4. Final simplification99.9%

    \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}} \]

Alternative 2: 88.5% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -2.8 \cdot 10^{-20} \lor \neg \left(z \leq 5.5 \cdot 10^{-79}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{-2}{\frac{t}{z}}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -2.8e-20) (not (<= z 5.5e-79)))
   (- x (/ y z))
   (- x (/ -2.0 (/ t z)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -2.8e-20) || !(z <= 5.5e-79)) {
		tmp = x - (y / z);
	} else {
		tmp = x - (-2.0 / (t / 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) :: tmp
    if ((z <= (-2.8d-20)) .or. (.not. (z <= 5.5d-79))) then
        tmp = x - (y / z)
    else
        tmp = x - ((-2.0d0) / (t / z))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -2.8e-20) || !(z <= 5.5e-79)) {
		tmp = x - (y / z);
	} else {
		tmp = x - (-2.0 / (t / z));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -2.8e-20) or not (z <= 5.5e-79):
		tmp = x - (y / z)
	else:
		tmp = x - (-2.0 / (t / z))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -2.8e-20) || !(z <= 5.5e-79))
		tmp = Float64(x - Float64(y / z));
	else
		tmp = Float64(x - Float64(-2.0 / Float64(t / z)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z <= -2.8e-20) || ~((z <= 5.5e-79)))
		tmp = x - (y / z);
	else
		tmp = x - (-2.0 / (t / z));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -2.8e-20], N[Not[LessEqual[z, 5.5e-79]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], N[(x - N[(-2.0 / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -2.8 \cdot 10^{-20} \lor \neg \left(z \leq 5.5 \cdot 10^{-79}\right):\\
\;\;\;\;x - \frac{y}{z}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -2.8000000000000003e-20 or 5.4999999999999997e-79 < z

    1. Initial program 78.5%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg78.5%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*90.8%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. *-commutative90.8%

        \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
      4. associate-/l*90.8%

        \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
      5. distribute-neg-frac90.8%

        \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
      6. metadata-eval90.8%

        \[\leadsto x + \frac{\color{blue}{-2}}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}} \]
      7. associate-/l/78.5%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
      8. div-sub78.4%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
      9. times-frac92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
      10. *-inverses92.9%

        \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
      11. *-rgt-identity92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      12. *-commutative92.9%

        \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
      13. associate-*l/92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
      14. *-commutative92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      15. times-frac99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
      16. *-inverses99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
      17. *-lft-identity99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
    4. Taylor expanded in z around inf 91.7%

      \[\leadsto \color{blue}{-1 \cdot \frac{y}{z} + x} \]
    5. Step-by-step derivation
      1. +-commutative91.7%

        \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
      2. mul-1-neg91.7%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      3. sub-neg91.7%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified91.7%

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

    if -2.8000000000000003e-20 < z < 5.4999999999999997e-79

    1. Initial program 93.9%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. associate-/l*94.8%

        \[\leadsto x - \color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      2. *-commutative94.8%

        \[\leadsto x - \frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}} \]
      3. associate-*r/94.8%

        \[\leadsto x - \color{blue}{2 \cdot \frac{y}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}} \]
      4. div-sub94.6%

        \[\leadsto x - 2 \cdot \frac{y}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{z} - \frac{y \cdot t}{z}}} \]
      5. *-commutative94.6%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{\color{blue}{z \cdot \left(z \cdot 2\right)}}{z} - \frac{y \cdot t}{z}} \]
      6. associate-/l*99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\color{blue}{\frac{z}{\frac{z}{z \cdot 2}}} - \frac{y \cdot t}{z}} \]
      7. associate-/r*99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{z}{\color{blue}{\frac{\frac{z}{z}}{2}}} - \frac{y \cdot t}{z}} \]
      8. *-inverses99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{z}{\frac{\color{blue}{1}}{2}} - \frac{y \cdot t}{z}} \]
      9. metadata-eval99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{z}{\color{blue}{0.5}} - \frac{y \cdot t}{z}} \]
      10. *-commutative99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{z}{0.5} - \frac{\color{blue}{t \cdot y}}{z}} \]
      11. associate-*l/99.0%

        \[\leadsto x - 2 \cdot \frac{y}{\frac{z}{0.5} - \color{blue}{\frac{t}{z} \cdot y}} \]
    3. Simplified99.0%

      \[\leadsto \color{blue}{x - 2 \cdot \frac{y}{\frac{z}{0.5} - \frac{t}{z} \cdot y}} \]
    4. Taylor expanded in y around inf 92.3%

      \[\leadsto x - \color{blue}{-2 \cdot \frac{z}{t}} \]
    5. Step-by-step derivation
      1. associate-*r/92.3%

        \[\leadsto x - \color{blue}{\frac{-2 \cdot z}{t}} \]
      2. associate-/l*92.2%

        \[\leadsto x - \color{blue}{\frac{-2}{\frac{t}{z}}} \]
    6. Simplified92.2%

      \[\leadsto x - \color{blue}{\frac{-2}{\frac{t}{z}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification91.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -2.8 \cdot 10^{-20} \lor \neg \left(z \leq 5.5 \cdot 10^{-79}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{-2}{\frac{t}{z}}\\ \end{array} \]

Alternative 3: 88.5% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -7.5 \cdot 10^{-13} \lor \neg \left(z \leq 8.2 \cdot 10^{-79}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{z}{t \cdot -0.5}\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -7.5e-13) (not (<= z 8.2e-79)))
   (- x (/ y z))
   (- x (/ z (* t -0.5)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -7.5e-13) || !(z <= 8.2e-79)) {
		tmp = x - (y / z);
	} else {
		tmp = x - (z / (t * -0.5));
	}
	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 <= (-7.5d-13)) .or. (.not. (z <= 8.2d-79))) then
        tmp = x - (y / z)
    else
        tmp = x - (z / (t * (-0.5d0)))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -7.5e-13) || !(z <= 8.2e-79)) {
		tmp = x - (y / z);
	} else {
		tmp = x - (z / (t * -0.5));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -7.5e-13) or not (z <= 8.2e-79):
		tmp = x - (y / z)
	else:
		tmp = x - (z / (t * -0.5))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -7.5e-13) || !(z <= 8.2e-79))
		tmp = Float64(x - Float64(y / z));
	else
		tmp = Float64(x - Float64(z / Float64(t * -0.5)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z <= -7.5e-13) || ~((z <= 8.2e-79)))
		tmp = x - (y / z);
	else
		tmp = x - (z / (t * -0.5));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -7.5e-13], N[Not[LessEqual[z, 8.2e-79]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], N[(x - N[(z / N[(t * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -7.5 \cdot 10^{-13} \lor \neg \left(z \leq 8.2 \cdot 10^{-79}\right):\\
\;\;\;\;x - \frac{y}{z}\\

\mathbf{else}:\\
\;\;\;\;x - \frac{z}{t \cdot -0.5}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -7.5000000000000004e-13 or 8.19999999999999987e-79 < z

    1. Initial program 78.5%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg78.5%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*90.8%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. *-commutative90.8%

        \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
      4. associate-/l*90.8%

        \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
      5. distribute-neg-frac90.8%

        \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
      6. metadata-eval90.8%

        \[\leadsto x + \frac{\color{blue}{-2}}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}} \]
      7. associate-/l/78.5%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
      8. div-sub78.4%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
      9. times-frac92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
      10. *-inverses92.9%

        \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
      11. *-rgt-identity92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      12. *-commutative92.9%

        \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
      13. associate-*l/92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
      14. *-commutative92.9%

        \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      15. times-frac99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
      16. *-inverses99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
      17. *-lft-identity99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
    4. Taylor expanded in z around inf 91.7%

      \[\leadsto \color{blue}{-1 \cdot \frac{y}{z} + x} \]
    5. Step-by-step derivation
      1. +-commutative91.7%

        \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
      2. mul-1-neg91.7%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      3. sub-neg91.7%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified91.7%

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

    if -7.5000000000000004e-13 < z < 8.19999999999999987e-79

    1. Initial program 93.9%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. *-commutative93.9%

        \[\leadsto x - \frac{\color{blue}{z \cdot \left(y \cdot 2\right)}}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
      2. associate-/l*95.7%

        \[\leadsto x - \color{blue}{\frac{z}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot 2}}} \]
      3. div-sub95.6%

        \[\leadsto x - \frac{z}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot 2} - \frac{y \cdot t}{y \cdot 2}}} \]
      4. sub-neg95.6%

        \[\leadsto x - \frac{z}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot 2} + \left(-\frac{y \cdot t}{y \cdot 2}\right)}} \]
      5. *-commutative95.6%

        \[\leadsto x - \frac{z}{\frac{\color{blue}{\left(2 \cdot z\right)} \cdot z}{y \cdot 2} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      6. associate-*l*95.6%

        \[\leadsto x - \frac{z}{\frac{\color{blue}{2 \cdot \left(z \cdot z\right)}}{y \cdot 2} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      7. *-commutative95.6%

        \[\leadsto x - \frac{z}{\frac{2 \cdot \left(z \cdot z\right)}{\color{blue}{2 \cdot y}} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      8. times-frac95.6%

        \[\leadsto x - \frac{z}{\color{blue}{\frac{2}{2} \cdot \frac{z \cdot z}{y}} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      9. metadata-eval95.6%

        \[\leadsto x - \frac{z}{\color{blue}{1} \cdot \frac{z \cdot z}{y} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      10. *-lft-identity95.6%

        \[\leadsto x - \frac{z}{\color{blue}{\frac{z \cdot z}{y}} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      11. associate-*r/99.0%

        \[\leadsto x - \frac{z}{\color{blue}{z \cdot \frac{z}{y}} + \left(-\frac{y \cdot t}{y \cdot 2}\right)} \]
      12. fma-def99.2%

        \[\leadsto x - \frac{z}{\color{blue}{\mathsf{fma}\left(z, \frac{z}{y}, -\frac{y \cdot t}{y \cdot 2}\right)}} \]
      13. associate-/r*99.2%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, -\color{blue}{\frac{\frac{y \cdot t}{y}}{2}}\right)} \]
      14. distribute-neg-frac99.2%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \color{blue}{\frac{-\frac{y \cdot t}{y}}{2}}\right)} \]
      15. *-commutative99.2%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \frac{-\frac{\color{blue}{t \cdot y}}{y}}{2}\right)} \]
      16. associate-/l*99.9%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \frac{-\color{blue}{\frac{t}{\frac{y}{y}}}}{2}\right)} \]
      17. *-inverses99.9%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \frac{-\frac{t}{\color{blue}{1}}}{2}\right)} \]
      18. /-rgt-identity99.9%

        \[\leadsto x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \frac{-\color{blue}{t}}{2}\right)} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{x - \frac{z}{\mathsf{fma}\left(z, \frac{z}{y}, \frac{-t}{2}\right)}} \]
    4. Taylor expanded in z around 0 92.3%

      \[\leadsto x - \frac{z}{\color{blue}{-0.5 \cdot t}} \]
    5. Step-by-step derivation
      1. *-commutative92.3%

        \[\leadsto x - \frac{z}{\color{blue}{t \cdot -0.5}} \]
    6. Simplified92.3%

      \[\leadsto x - \frac{z}{\color{blue}{t \cdot -0.5}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification92.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -7.5 \cdot 10^{-13} \lor \neg \left(z \leq 8.2 \cdot 10^{-79}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x - \frac{z}{t \cdot -0.5}\\ \end{array} \]

Alternative 4: 81.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -2.2 \cdot 10^{+59} \lor \neg \left(z \leq 6.2 \cdot 10^{-107}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (or (<= z -2.2e+59) (not (<= z 6.2e-107))) (- x (/ y z)) x))
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z <= -2.2e+59) || !(z <= 6.2e-107)) {
		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 <= (-2.2d+59)) .or. (.not. (z <= 6.2d-107))) 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 <= -2.2e+59) || !(z <= 6.2e-107)) {
		tmp = x - (y / z);
	} else {
		tmp = x;
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if (z <= -2.2e+59) or not (z <= 6.2e-107):
		tmp = x - (y / z)
	else:
		tmp = x
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if ((z <= -2.2e+59) || !(z <= 6.2e-107))
		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 <= -2.2e+59) || ~((z <= 6.2e-107)))
		tmp = x - (y / z);
	else
		tmp = x;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[Or[LessEqual[z, -2.2e+59], N[Not[LessEqual[z, 6.2e-107]], $MachinePrecision]], N[(x - N[(y / z), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -2.2 \cdot 10^{+59} \lor \neg \left(z \leq 6.2 \cdot 10^{-107}\right):\\
\;\;\;\;x - \frac{y}{z}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -2.2e59 or 6.20000000000000043e-107 < z

    1. Initial program 78.3%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg78.3%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*90.4%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. *-commutative90.4%

        \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
      4. associate-/l*90.4%

        \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
      5. distribute-neg-frac90.4%

        \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
      6. metadata-eval90.4%

        \[\leadsto x + \frac{\color{blue}{-2}}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}} \]
      7. associate-/l/78.3%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
      8. div-sub78.2%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
      9. times-frac93.4%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
      10. *-inverses93.4%

        \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
      11. *-rgt-identity93.4%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      12. *-commutative93.4%

        \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
      13. associate-*l/93.3%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
      14. *-commutative93.3%

        \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      15. times-frac99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
      16. *-inverses99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
      17. *-lft-identity99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
    4. Taylor expanded in z around inf 93.3%

      \[\leadsto \color{blue}{-1 \cdot \frac{y}{z} + x} \]
    5. Step-by-step derivation
      1. +-commutative93.3%

        \[\leadsto \color{blue}{x + -1 \cdot \frac{y}{z}} \]
      2. mul-1-neg93.3%

        \[\leadsto x + \color{blue}{\left(-\frac{y}{z}\right)} \]
      3. sub-neg93.3%

        \[\leadsto \color{blue}{x - \frac{y}{z}} \]
    6. Simplified93.3%

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

    if -2.2e59 < z < 6.20000000000000043e-107

    1. Initial program 93.4%

      \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
    2. Step-by-step derivation
      1. sub-neg93.4%

        \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
      2. associate-/l*95.0%

        \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
      3. *-commutative95.0%

        \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
      4. associate-/l*95.1%

        \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
      5. distribute-neg-frac95.1%

        \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
      6. metadata-eval95.1%

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

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
      8. div-sub74.8%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
      9. times-frac91.7%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
      10. *-inverses91.7%

        \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
      11. *-rgt-identity91.7%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      12. *-commutative91.7%

        \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
      13. associate-*l/91.7%

        \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
      14. *-commutative91.7%

        \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
      15. times-frac99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
      16. *-inverses99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
      17. *-lft-identity99.9%

        \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
    4. Taylor expanded in x around inf 79.1%

      \[\leadsto \color{blue}{x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification86.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -2.2 \cdot 10^{+59} \lor \neg \left(z \leq 6.2 \cdot 10^{-107}\right):\\ \;\;\;\;x - \frac{y}{z}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \]

Alternative 5: 75.9% 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 85.3%

    \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
  2. Step-by-step derivation
    1. sub-neg85.3%

      \[\leadsto \color{blue}{x + \left(-\frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}\right)} \]
    2. associate-/l*92.6%

      \[\leadsto x + \left(-\color{blue}{\frac{y \cdot 2}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}}\right) \]
    3. *-commutative92.6%

      \[\leadsto x + \left(-\frac{\color{blue}{2 \cdot y}}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}\right) \]
    4. associate-/l*92.5%

      \[\leadsto x + \left(-\color{blue}{\frac{2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}}\right) \]
    5. distribute-neg-frac92.5%

      \[\leadsto x + \color{blue}{\frac{-2}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}}} \]
    6. metadata-eval92.5%

      \[\leadsto x + \frac{\color{blue}{-2}}{\frac{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{z}}{y}} \]
    7. associate-/l/85.3%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z - y \cdot t}{y \cdot z}}} \]
    8. div-sub76.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{\left(z \cdot 2\right) \cdot z}{y \cdot z} - \frac{y \cdot t}{y \cdot z}}} \]
    9. times-frac92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y} \cdot \frac{z}{z}} - \frac{y \cdot t}{y \cdot z}} \]
    10. *-inverses92.6%

      \[\leadsto x + \frac{-2}{\frac{z \cdot 2}{y} \cdot \color{blue}{1} - \frac{y \cdot t}{y \cdot z}} \]
    11. *-rgt-identity92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{z \cdot 2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
    12. *-commutative92.6%

      \[\leadsto x + \frac{-2}{\frac{\color{blue}{2 \cdot z}}{y} - \frac{y \cdot t}{y \cdot z}} \]
    13. associate-*l/92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{\frac{2}{y} \cdot z} - \frac{y \cdot t}{y \cdot z}} \]
    14. *-commutative92.6%

      \[\leadsto x + \frac{-2}{\color{blue}{z \cdot \frac{2}{y}} - \frac{y \cdot t}{y \cdot z}} \]
    15. times-frac99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{y}{y} \cdot \frac{t}{z}}} \]
    16. *-inverses99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{1} \cdot \frac{t}{z}} \]
    17. *-lft-identity99.9%

      \[\leadsto x + \frac{-2}{z \cdot \frac{2}{y} - \color{blue}{\frac{t}{z}}} \]
  3. Simplified99.9%

    \[\leadsto \color{blue}{x + \frac{-2}{z \cdot \frac{2}{y} - \frac{t}{z}}} \]
  4. Taylor expanded in x around inf 79.3%

    \[\leadsto \color{blue}{x} \]
  5. Final simplification79.3%

    \[\leadsto x \]

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 2023207 
(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)))))