Diagrams.Solve.Tridiagonal:solveTriDiagonal from diagrams-solve-0.1, A

Percentage Accurate: 85.2% → 91.5%
Time: 12.0s
Alternatives: 5
Speedup: 0.5×

Specification

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

\\
\frac{x - y \cdot z}{t - a \cdot z}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 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: 85.2% accurate, 1.0× speedup?

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

\\
\frac{x - y \cdot z}{t - a \cdot z}
\end{array}

Alternative 1: 91.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -1.6 \cdot 10^{+117} \lor \neg \left(z \leq 9.6 \cdot 10^{+156}\right):\\ \;\;\;\;\frac{y - \frac{x}{z}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x - z \cdot y}{t - z \cdot a}\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= z -1.6e+117) (not (<= z 9.6e+156)))
   (/ (- y (/ x z)) a)
   (/ (- x (* z y)) (- t (* z a)))))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -1.6e+117) || !(z <= 9.6e+156)) {
		tmp = (y - (x / z)) / a;
	} else {
		tmp = (x - (z * y)) / (t - (z * a));
	}
	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 ((z <= (-1.6d+117)) .or. (.not. (z <= 9.6d+156))) then
        tmp = (y - (x / z)) / a
    else
        tmp = (x - (z * y)) / (t - (z * a))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -1.6e+117) || !(z <= 9.6e+156)) {
		tmp = (y - (x / z)) / a;
	} else {
		tmp = (x - (z * y)) / (t - (z * a));
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (z <= -1.6e+117) or not (z <= 9.6e+156):
		tmp = (y - (x / z)) / a
	else:
		tmp = (x - (z * y)) / (t - (z * a))
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((z <= -1.6e+117) || !(z <= 9.6e+156))
		tmp = Float64(Float64(y - Float64(x / z)) / a);
	else
		tmp = Float64(Float64(x - Float64(z * y)) / Float64(t - Float64(z * a)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((z <= -1.6e+117) || ~((z <= 9.6e+156)))
		tmp = (y - (x / z)) / a;
	else
		tmp = (x - (z * y)) / (t - (z * a));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[z, -1.6e+117], N[Not[LessEqual[z, 9.6e+156]], $MachinePrecision]], N[(N[(y - N[(x / z), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision], N[(N[(x - N[(z * y), $MachinePrecision]), $MachinePrecision] / N[(t - N[(z * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -1.6 \cdot 10^{+117} \lor \neg \left(z \leq 9.6 \cdot 10^{+156}\right):\\
\;\;\;\;\frac{y - \frac{x}{z}}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -1.60000000000000002e117 or 9.6000000000000004e156 < z

    1. Initial program 53.0%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative53.0%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified53.0%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in t around 0 45.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{x - y \cdot z}{a \cdot z}} \]
    6. Step-by-step derivation
      1. associate-*r/45.2%

        \[\leadsto \color{blue}{\frac{-1 \cdot \left(x - y \cdot z\right)}{a \cdot z}} \]
      2. neg-mul-145.2%

        \[\leadsto \frac{\color{blue}{-\left(x - y \cdot z\right)}}{a \cdot z} \]
      3. neg-sub045.2%

        \[\leadsto \frac{\color{blue}{0 - \left(x - y \cdot z\right)}}{a \cdot z} \]
      4. sub-neg45.2%

        \[\leadsto \frac{0 - \color{blue}{\left(x + \left(-y \cdot z\right)\right)}}{a \cdot z} \]
      5. distribute-rgt-neg-out45.2%

        \[\leadsto \frac{0 - \left(x + \color{blue}{y \cdot \left(-z\right)}\right)}{a \cdot z} \]
      6. +-commutative45.2%

        \[\leadsto \frac{0 - \color{blue}{\left(y \cdot \left(-z\right) + x\right)}}{a \cdot z} \]
      7. associate--r+45.2%

        \[\leadsto \frac{\color{blue}{\left(0 - y \cdot \left(-z\right)\right) - x}}{a \cdot z} \]
      8. neg-sub045.2%

        \[\leadsto \frac{\color{blue}{\left(-y \cdot \left(-z\right)\right)} - x}{a \cdot z} \]
      9. distribute-rgt-neg-out45.2%

        \[\leadsto \frac{\left(-\color{blue}{\left(-y \cdot z\right)}\right) - x}{a \cdot z} \]
      10. remove-double-neg45.2%

        \[\leadsto \frac{\color{blue}{y \cdot z} - x}{a \cdot z} \]
      11. *-commutative45.2%

        \[\leadsto \frac{y \cdot z - x}{\color{blue}{z \cdot a}} \]
    7. Simplified45.2%

      \[\leadsto \color{blue}{\frac{y \cdot z - x}{z \cdot a}} \]
    8. Step-by-step derivation
      1. *-un-lft-identity45.2%

        \[\leadsto \frac{\color{blue}{1 \cdot \left(y \cdot z - x\right)}}{z \cdot a} \]
      2. times-frac54.5%

        \[\leadsto \color{blue}{\frac{1}{z} \cdot \frac{y \cdot z - x}{a}} \]
      3. *-commutative54.5%

        \[\leadsto \frac{1}{z} \cdot \frac{\color{blue}{z \cdot y} - x}{a} \]
    9. Applied egg-rr54.5%

      \[\leadsto \color{blue}{\frac{1}{z} \cdot \frac{z \cdot y - x}{a}} \]
    10. Step-by-step derivation
      1. associate-*r/58.4%

        \[\leadsto \color{blue}{\frac{\frac{1}{z} \cdot \left(z \cdot y - x\right)}{a}} \]
      2. *-commutative58.4%

        \[\leadsto \frac{\frac{1}{z} \cdot \left(\color{blue}{y \cdot z} - x\right)}{a} \]
    11. Simplified58.4%

      \[\leadsto \color{blue}{\frac{\frac{1}{z} \cdot \left(y \cdot z - x\right)}{a}} \]
    12. Taylor expanded in z around 0 58.5%

      \[\leadsto \frac{\color{blue}{\frac{-1 \cdot x + y \cdot z}{z}}}{a} \]
    13. Step-by-step derivation
      1. neg-mul-158.5%

        \[\leadsto \frac{\frac{\color{blue}{\left(-x\right)} + y \cdot z}{z}}{a} \]
      2. +-commutative58.5%

        \[\leadsto \frac{\frac{\color{blue}{y \cdot z + \left(-x\right)}}{z}}{a} \]
      3. *-commutative58.5%

        \[\leadsto \frac{\frac{\color{blue}{z \cdot y} + \left(-x\right)}{z}}{a} \]
      4. sub-neg58.5%

        \[\leadsto \frac{\frac{\color{blue}{z \cdot y - x}}{z}}{a} \]
      5. div-sub58.5%

        \[\leadsto \frac{\color{blue}{\frac{z \cdot y}{z} - \frac{x}{z}}}{a} \]
      6. *-lft-identity58.5%

        \[\leadsto \frac{\frac{\color{blue}{1 \cdot \left(z \cdot y\right)}}{z} - \frac{x}{z}}{a} \]
      7. associate-*l/58.5%

        \[\leadsto \frac{\color{blue}{\frac{1}{z} \cdot \left(z \cdot y\right)} - \frac{x}{z}}{a} \]
      8. associate-*r*88.2%

        \[\leadsto \frac{\color{blue}{\left(\frac{1}{z} \cdot z\right) \cdot y} - \frac{x}{z}}{a} \]
      9. lft-mult-inverse88.3%

        \[\leadsto \frac{\color{blue}{1} \cdot y - \frac{x}{z}}{a} \]
      10. *-lft-identity88.3%

        \[\leadsto \frac{\color{blue}{y} - \frac{x}{z}}{a} \]
    14. Simplified88.3%

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

    if -1.60000000000000002e117 < z < 9.6000000000000004e156

    1. Initial program 95.7%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification93.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -1.6 \cdot 10^{+117} \lor \neg \left(z \leq 9.6 \cdot 10^{+156}\right):\\ \;\;\;\;\frac{y - \frac{x}{z}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x - z \cdot y}{t - z \cdot a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 73.5% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -2.05 \cdot 10^{-50} \lor \neg \left(z \leq 58000000000000\right):\\ \;\;\;\;\frac{y - \frac{x}{z}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t - z \cdot a}\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= z -2.05e-50) (not (<= z 58000000000000.0)))
   (/ (- y (/ x z)) a)
   (/ x (- t (* z a)))))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -2.05e-50) || !(z <= 58000000000000.0)) {
		tmp = (y - (x / z)) / a;
	} else {
		tmp = x / (t - (z * a));
	}
	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 ((z <= (-2.05d-50)) .or. (.not. (z <= 58000000000000.0d0))) then
        tmp = (y - (x / z)) / a
    else
        tmp = x / (t - (z * a))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -2.05e-50) || !(z <= 58000000000000.0)) {
		tmp = (y - (x / z)) / a;
	} else {
		tmp = x / (t - (z * a));
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (z <= -2.05e-50) or not (z <= 58000000000000.0):
		tmp = (y - (x / z)) / a
	else:
		tmp = x / (t - (z * a))
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((z <= -2.05e-50) || !(z <= 58000000000000.0))
		tmp = Float64(Float64(y - Float64(x / z)) / a);
	else
		tmp = Float64(x / Float64(t - Float64(z * a)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((z <= -2.05e-50) || ~((z <= 58000000000000.0)))
		tmp = (y - (x / z)) / a;
	else
		tmp = x / (t - (z * a));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[z, -2.05e-50], N[Not[LessEqual[z, 58000000000000.0]], $MachinePrecision]], N[(N[(y - N[(x / z), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision], N[(x / N[(t - N[(z * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -2.05 \cdot 10^{-50} \lor \neg \left(z \leq 58000000000000\right):\\
\;\;\;\;\frac{y - \frac{x}{z}}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -2.04999999999999993e-50 or 5.8e13 < z

    1. Initial program 68.6%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative68.6%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified68.6%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in t around 0 50.6%

      \[\leadsto \color{blue}{-1 \cdot \frac{x - y \cdot z}{a \cdot z}} \]
    6. Step-by-step derivation
      1. associate-*r/50.6%

        \[\leadsto \color{blue}{\frac{-1 \cdot \left(x - y \cdot z\right)}{a \cdot z}} \]
      2. neg-mul-150.6%

        \[\leadsto \frac{\color{blue}{-\left(x - y \cdot z\right)}}{a \cdot z} \]
      3. neg-sub050.6%

        \[\leadsto \frac{\color{blue}{0 - \left(x - y \cdot z\right)}}{a \cdot z} \]
      4. sub-neg50.6%

        \[\leadsto \frac{0 - \color{blue}{\left(x + \left(-y \cdot z\right)\right)}}{a \cdot z} \]
      5. distribute-rgt-neg-out50.6%

        \[\leadsto \frac{0 - \left(x + \color{blue}{y \cdot \left(-z\right)}\right)}{a \cdot z} \]
      6. +-commutative50.6%

        \[\leadsto \frac{0 - \color{blue}{\left(y \cdot \left(-z\right) + x\right)}}{a \cdot z} \]
      7. associate--r+50.6%

        \[\leadsto \frac{\color{blue}{\left(0 - y \cdot \left(-z\right)\right) - x}}{a \cdot z} \]
      8. neg-sub050.6%

        \[\leadsto \frac{\color{blue}{\left(-y \cdot \left(-z\right)\right)} - x}{a \cdot z} \]
      9. distribute-rgt-neg-out50.6%

        \[\leadsto \frac{\left(-\color{blue}{\left(-y \cdot z\right)}\right) - x}{a \cdot z} \]
      10. remove-double-neg50.6%

        \[\leadsto \frac{\color{blue}{y \cdot z} - x}{a \cdot z} \]
      11. *-commutative50.6%

        \[\leadsto \frac{y \cdot z - x}{\color{blue}{z \cdot a}} \]
    7. Simplified50.6%

      \[\leadsto \color{blue}{\frac{y \cdot z - x}{z \cdot a}} \]
    8. Step-by-step derivation
      1. *-un-lft-identity50.6%

        \[\leadsto \frac{\color{blue}{1 \cdot \left(y \cdot z - x\right)}}{z \cdot a} \]
      2. times-frac56.4%

        \[\leadsto \color{blue}{\frac{1}{z} \cdot \frac{y \cdot z - x}{a}} \]
      3. *-commutative56.4%

        \[\leadsto \frac{1}{z} \cdot \frac{\color{blue}{z \cdot y} - x}{a} \]
    9. Applied egg-rr56.4%

      \[\leadsto \color{blue}{\frac{1}{z} \cdot \frac{z \cdot y - x}{a}} \]
    10. Step-by-step derivation
      1. associate-*r/60.6%

        \[\leadsto \color{blue}{\frac{\frac{1}{z} \cdot \left(z \cdot y - x\right)}{a}} \]
      2. *-commutative60.6%

        \[\leadsto \frac{\frac{1}{z} \cdot \left(\color{blue}{y \cdot z} - x\right)}{a} \]
    11. Simplified60.6%

      \[\leadsto \color{blue}{\frac{\frac{1}{z} \cdot \left(y \cdot z - x\right)}{a}} \]
    12. Taylor expanded in z around 0 60.7%

      \[\leadsto \frac{\color{blue}{\frac{-1 \cdot x + y \cdot z}{z}}}{a} \]
    13. Step-by-step derivation
      1. neg-mul-160.7%

        \[\leadsto \frac{\frac{\color{blue}{\left(-x\right)} + y \cdot z}{z}}{a} \]
      2. +-commutative60.7%

        \[\leadsto \frac{\frac{\color{blue}{y \cdot z + \left(-x\right)}}{z}}{a} \]
      3. *-commutative60.7%

        \[\leadsto \frac{\frac{\color{blue}{z \cdot y} + \left(-x\right)}{z}}{a} \]
      4. sub-neg60.7%

        \[\leadsto \frac{\frac{\color{blue}{z \cdot y - x}}{z}}{a} \]
      5. div-sub60.7%

        \[\leadsto \frac{\color{blue}{\frac{z \cdot y}{z} - \frac{x}{z}}}{a} \]
      6. *-lft-identity60.7%

        \[\leadsto \frac{\frac{\color{blue}{1 \cdot \left(z \cdot y\right)}}{z} - \frac{x}{z}}{a} \]
      7. associate-*l/60.6%

        \[\leadsto \frac{\color{blue}{\frac{1}{z} \cdot \left(z \cdot y\right)} - \frac{x}{z}}{a} \]
      8. associate-*r*78.3%

        \[\leadsto \frac{\color{blue}{\left(\frac{1}{z} \cdot z\right) \cdot y} - \frac{x}{z}}{a} \]
      9. lft-mult-inverse78.4%

        \[\leadsto \frac{\color{blue}{1} \cdot y - \frac{x}{z}}{a} \]
      10. *-lft-identity78.4%

        \[\leadsto \frac{\color{blue}{y} - \frac{x}{z}}{a} \]
    14. Simplified78.4%

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

    if -2.04999999999999993e-50 < z < 5.8e13

    1. Initial program 99.8%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative99.8%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified99.8%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 78.6%

      \[\leadsto \color{blue}{\frac{x}{t - a \cdot z}} \]
    6. Step-by-step derivation
      1. *-commutative78.6%

        \[\leadsto \frac{x}{t - \color{blue}{z \cdot a}} \]
    7. Simplified78.6%

      \[\leadsto \color{blue}{\frac{x}{t - z \cdot a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification78.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -2.05 \cdot 10^{-50} \lor \neg \left(z \leq 58000000000000\right):\\ \;\;\;\;\frac{y - \frac{x}{z}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t - z \cdot a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 66.2% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -6 \cdot 10^{+69} \lor \neg \left(z \leq 2.7 \cdot 10^{+129}\right):\\ \;\;\;\;\frac{y}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t - z \cdot a}\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= z -6e+69) (not (<= z 2.7e+129))) (/ y a) (/ x (- t (* z a)))))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -6e+69) || !(z <= 2.7e+129)) {
		tmp = y / a;
	} else {
		tmp = x / (t - (z * a));
	}
	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 ((z <= (-6d+69)) .or. (.not. (z <= 2.7d+129))) then
        tmp = y / a
    else
        tmp = x / (t - (z * a))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -6e+69) || !(z <= 2.7e+129)) {
		tmp = y / a;
	} else {
		tmp = x / (t - (z * a));
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (z <= -6e+69) or not (z <= 2.7e+129):
		tmp = y / a
	else:
		tmp = x / (t - (z * a))
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((z <= -6e+69) || !(z <= 2.7e+129))
		tmp = Float64(y / a);
	else
		tmp = Float64(x / Float64(t - Float64(z * a)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((z <= -6e+69) || ~((z <= 2.7e+129)))
		tmp = y / a;
	else
		tmp = x / (t - (z * a));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[z, -6e+69], N[Not[LessEqual[z, 2.7e+129]], $MachinePrecision]], N[(y / a), $MachinePrecision], N[(x / N[(t - N[(z * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -6 \cdot 10^{+69} \lor \neg \left(z \leq 2.7 \cdot 10^{+129}\right):\\
\;\;\;\;\frac{y}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -5.99999999999999967e69 or 2.7000000000000001e129 < z

    1. Initial program 57.2%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative57.2%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified57.2%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in z around inf 71.9%

      \[\leadsto \color{blue}{\frac{y}{a}} \]

    if -5.99999999999999967e69 < z < 2.7000000000000001e129

    1. Initial program 97.0%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative97.0%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified97.0%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 72.0%

      \[\leadsto \color{blue}{\frac{x}{t - a \cdot z}} \]
    6. Step-by-step derivation
      1. *-commutative72.0%

        \[\leadsto \frac{x}{t - \color{blue}{z \cdot a}} \]
    7. Simplified72.0%

      \[\leadsto \color{blue}{\frac{x}{t - z \cdot a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification71.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -6 \cdot 10^{+69} \lor \neg \left(z \leq 2.7 \cdot 10^{+129}\right):\\ \;\;\;\;\frac{y}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t - z \cdot a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 55.5% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;z \leq -3.4 \cdot 10^{-105} \lor \neg \left(z \leq 7.6 \cdot 10^{-8}\right):\\ \;\;\;\;\frac{y}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t}\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (if (or (<= z -3.4e-105) (not (<= z 7.6e-8))) (/ y a) (/ x t)))
double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -3.4e-105) || !(z <= 7.6e-8)) {
		tmp = y / a;
	} else {
		tmp = x / 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 ((z <= (-3.4d-105)) .or. (.not. (z <= 7.6d-8))) then
        tmp = y / a
    else
        tmp = x / t
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double tmp;
	if ((z <= -3.4e-105) || !(z <= 7.6e-8)) {
		tmp = y / a;
	} else {
		tmp = x / t;
	}
	return tmp;
}
def code(x, y, z, t, a):
	tmp = 0
	if (z <= -3.4e-105) or not (z <= 7.6e-8):
		tmp = y / a
	else:
		tmp = x / t
	return tmp
function code(x, y, z, t, a)
	tmp = 0.0
	if ((z <= -3.4e-105) || !(z <= 7.6e-8))
		tmp = Float64(y / a);
	else
		tmp = Float64(x / t);
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	tmp = 0.0;
	if ((z <= -3.4e-105) || ~((z <= 7.6e-8)))
		tmp = y / a;
	else
		tmp = x / t;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := If[Or[LessEqual[z, -3.4e-105], N[Not[LessEqual[z, 7.6e-8]], $MachinePrecision]], N[(y / a), $MachinePrecision], N[(x / t), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;z \leq -3.4 \cdot 10^{-105} \lor \neg \left(z \leq 7.6 \cdot 10^{-8}\right):\\
\;\;\;\;\frac{y}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if z < -3.39999999999999992e-105 or 7.60000000000000056e-8 < z

    1. Initial program 71.7%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative71.7%

        \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
    3. Simplified71.7%

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in z around inf 57.1%

      \[\leadsto \color{blue}{\frac{y}{a}} \]

    if -3.39999999999999992e-105 < z < 7.60000000000000056e-8

    1. Initial program 99.9%

      \[\frac{x - y \cdot z}{t - a \cdot z} \]
    2. Step-by-step derivation
      1. *-commutative99.9%

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

      \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
    4. Add Preprocessing
    5. Taylor expanded in z around 0 67.8%

      \[\leadsto \color{blue}{\frac{x}{t}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification61.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -3.4 \cdot 10^{-105} \lor \neg \left(z \leq 7.6 \cdot 10^{-8}\right):\\ \;\;\;\;\frac{y}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 36.3% accurate, 3.7× speedup?

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

\\
\frac{x}{t}
\end{array}
Derivation
  1. Initial program 83.4%

    \[\frac{x - y \cdot z}{t - a \cdot z} \]
  2. Step-by-step derivation
    1. *-commutative83.4%

      \[\leadsto \frac{x - y \cdot z}{t - \color{blue}{z \cdot a}} \]
  3. Simplified83.4%

    \[\leadsto \color{blue}{\frac{x - y \cdot z}{t - z \cdot a}} \]
  4. Add Preprocessing
  5. Taylor expanded in z around 0 36.7%

    \[\leadsto \color{blue}{\frac{x}{t}} \]
  6. Add Preprocessing

Developer Target 1: 97.3% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := t - a \cdot z\\ t_2 := \frac{x}{t\_1} - \frac{y}{\frac{t}{z} - a}\\ \mathbf{if}\;z < -32113435955957344:\\ \;\;\;\;t\_2\\ \mathbf{elif}\;z < 3.5139522372978296 \cdot 10^{-86}:\\ \;\;\;\;\left(x - y \cdot z\right) \cdot \frac{1}{t\_1}\\ \mathbf{else}:\\ \;\;\;\;t\_2\\ \end{array} \end{array} \]
(FPCore (x y z t a)
 :precision binary64
 (let* ((t_1 (- t (* a z))) (t_2 (- (/ x t_1) (/ y (- (/ t z) a)))))
   (if (< z -32113435955957344.0)
     t_2
     (if (< z 3.5139522372978296e-86) (* (- x (* y z)) (/ 1.0 t_1)) t_2))))
double code(double x, double y, double z, double t, double a) {
	double t_1 = t - (a * z);
	double t_2 = (x / t_1) - (y / ((t / z) - a));
	double tmp;
	if (z < -32113435955957344.0) {
		tmp = t_2;
	} else if (z < 3.5139522372978296e-86) {
		tmp = (x - (y * z)) * (1.0 / t_1);
	} else {
		tmp = t_2;
	}
	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) :: t_1
    real(8) :: t_2
    real(8) :: tmp
    t_1 = t - (a * z)
    t_2 = (x / t_1) - (y / ((t / z) - a))
    if (z < (-32113435955957344.0d0)) then
        tmp = t_2
    else if (z < 3.5139522372978296d-86) then
        tmp = (x - (y * z)) * (1.0d0 / t_1)
    else
        tmp = t_2
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t, double a) {
	double t_1 = t - (a * z);
	double t_2 = (x / t_1) - (y / ((t / z) - a));
	double tmp;
	if (z < -32113435955957344.0) {
		tmp = t_2;
	} else if (z < 3.5139522372978296e-86) {
		tmp = (x - (y * z)) * (1.0 / t_1);
	} else {
		tmp = t_2;
	}
	return tmp;
}
def code(x, y, z, t, a):
	t_1 = t - (a * z)
	t_2 = (x / t_1) - (y / ((t / z) - a))
	tmp = 0
	if z < -32113435955957344.0:
		tmp = t_2
	elif z < 3.5139522372978296e-86:
		tmp = (x - (y * z)) * (1.0 / t_1)
	else:
		tmp = t_2
	return tmp
function code(x, y, z, t, a)
	t_1 = Float64(t - Float64(a * z))
	t_2 = Float64(Float64(x / t_1) - Float64(y / Float64(Float64(t / z) - a)))
	tmp = 0.0
	if (z < -32113435955957344.0)
		tmp = t_2;
	elseif (z < 3.5139522372978296e-86)
		tmp = Float64(Float64(x - Float64(y * z)) * Float64(1.0 / t_1));
	else
		tmp = t_2;
	end
	return tmp
end
function tmp_2 = code(x, y, z, t, a)
	t_1 = t - (a * z);
	t_2 = (x / t_1) - (y / ((t / z) - a));
	tmp = 0.0;
	if (z < -32113435955957344.0)
		tmp = t_2;
	elseif (z < 3.5139522372978296e-86)
		tmp = (x - (y * z)) * (1.0 / t_1);
	else
		tmp = t_2;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_, a_] := Block[{t$95$1 = N[(t - N[(a * z), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[(x / t$95$1), $MachinePrecision] - N[(y / N[(N[(t / z), $MachinePrecision] - a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[Less[z, -32113435955957344.0], t$95$2, If[Less[z, 3.5139522372978296e-86], N[(N[(x - N[(y * z), $MachinePrecision]), $MachinePrecision] * N[(1.0 / t$95$1), $MachinePrecision]), $MachinePrecision], t$95$2]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := t - a \cdot z\\
t_2 := \frac{x}{t\_1} - \frac{y}{\frac{t}{z} - a}\\
\mathbf{if}\;z < -32113435955957344:\\
\;\;\;\;t\_2\\

\mathbf{elif}\;z < 3.5139522372978296 \cdot 10^{-86}:\\
\;\;\;\;\left(x - y \cdot z\right) \cdot \frac{1}{t\_1}\\

\mathbf{else}:\\
\;\;\;\;t\_2\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024113 
(FPCore (x y z t a)
  :name "Diagrams.Solve.Tridiagonal:solveTriDiagonal from diagrams-solve-0.1, A"
  :precision binary64

  :alt
  (! :herbie-platform default (if (< z -32113435955957344) (- (/ x (- t (* a z))) (/ y (- (/ t z) a))) (if (< z 4392440296622287/125000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (* (- x (* y z)) (/ 1 (- t (* a z)))) (- (/ x (- t (* a z))) (/ y (- (/ t z) a))))))

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