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

Percentage Accurate: 95.8% → 99.6%
Time: 10.1s
Alternatives: 5
Speedup: 1.0×

Specification

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

\\
\frac{x}{y - z \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: 95.8% accurate, 1.0× speedup?

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

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

Alternative 1: 99.6% accurate, 0.4× speedup?

\[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} \mathbf{if}\;z \cdot t \leq -2 \cdot 10^{+261}:\\ \;\;\;\;\frac{\frac{x}{z}}{-t}\\ \mathbf{elif}\;z \cdot t \leq 4 \cdot 10^{+234}:\\ \;\;\;\;\frac{x}{y - z \cdot t}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{x}{t}}{-z}\\ \end{array} \end{array} \]
NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
(FPCore (x y z t)
 :precision binary64
 (if (<= (* z t) -2e+261)
   (/ (/ x z) (- t))
   (if (<= (* z t) 4e+234) (/ x (- y (* z t))) (/ (/ x t) (- z)))))
assert(x < y && y < z && z < t);
double code(double x, double y, double z, double t) {
	double tmp;
	if ((z * t) <= -2e+261) {
		tmp = (x / z) / -t;
	} else if ((z * t) <= 4e+234) {
		tmp = x / (y - (z * t));
	} else {
		tmp = (x / t) / -z;
	}
	return tmp;
}
NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
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 * t) <= (-2d+261)) then
        tmp = (x / z) / -t
    else if ((z * t) <= 4d+234) then
        tmp = x / (y - (z * t))
    else
        tmp = (x / t) / -z
    end if
    code = tmp
end function
assert x < y && y < z && z < t;
public static double code(double x, double y, double z, double t) {
	double tmp;
	if ((z * t) <= -2e+261) {
		tmp = (x / z) / -t;
	} else if ((z * t) <= 4e+234) {
		tmp = x / (y - (z * t));
	} else {
		tmp = (x / t) / -z;
	}
	return tmp;
}
[x, y, z, t] = sort([x, y, z, t])
def code(x, y, z, t):
	tmp = 0
	if (z * t) <= -2e+261:
		tmp = (x / z) / -t
	elif (z * t) <= 4e+234:
		tmp = x / (y - (z * t))
	else:
		tmp = (x / t) / -z
	return tmp
x, y, z, t = sort([x, y, z, t])
function code(x, y, z, t)
	tmp = 0.0
	if (Float64(z * t) <= -2e+261)
		tmp = Float64(Float64(x / z) / Float64(-t));
	elseif (Float64(z * t) <= 4e+234)
		tmp = Float64(x / Float64(y - Float64(z * t)));
	else
		tmp = Float64(Float64(x / t) / Float64(-z));
	end
	return tmp
end
x, y, z, t = num2cell(sort([x, y, z, t])){:}
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if ((z * t) <= -2e+261)
		tmp = (x / z) / -t;
	elseif ((z * t) <= 4e+234)
		tmp = x / (y - (z * t));
	else
		tmp = (x / t) / -z;
	end
	tmp_2 = tmp;
end
NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
code[x_, y_, z_, t_] := If[LessEqual[N[(z * t), $MachinePrecision], -2e+261], N[(N[(x / z), $MachinePrecision] / (-t)), $MachinePrecision], If[LessEqual[N[(z * t), $MachinePrecision], 4e+234], N[(x / N[(y - N[(z * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(x / t), $MachinePrecision] / (-z)), $MachinePrecision]]]
\begin{array}{l}
[x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
\\
\begin{array}{l}
\mathbf{if}\;z \cdot t \leq -2 \cdot 10^{+261}:\\
\;\;\;\;\frac{\frac{x}{z}}{-t}\\

\mathbf{elif}\;z \cdot t \leq 4 \cdot 10^{+234}:\\
\;\;\;\;\frac{x}{y - z \cdot t}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (*.f64 z t) < -1.9999999999999999e261

    1. Initial program 69.6%

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

        \[\leadsto \color{blue}{\frac{x}{y - z \cdot t}} \]
      2. clear-numN/A

        \[\leadsto \color{blue}{\frac{1}{\frac{y - z \cdot t}{x}}} \]
      3. div-invN/A

        \[\leadsto \frac{1}{\color{blue}{\left(y - z \cdot t\right) \cdot \frac{1}{x}}} \]
      4. associate-/r*N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{y - z \cdot t}}{\frac{1}{x}}} \]
      5. lift--.f64N/A

        \[\leadsto \frac{\frac{1}{\color{blue}{y - z \cdot t}}}{\frac{1}{x}} \]
      6. flip3--N/A

        \[\leadsto \frac{\frac{1}{\color{blue}{\frac{{y}^{3} - {\left(z \cdot t\right)}^{3}}{y \cdot y + \left(\left(z \cdot t\right) \cdot \left(z \cdot t\right) + y \cdot \left(z \cdot t\right)\right)}}}}{\frac{1}{x}} \]
      7. clear-numN/A

        \[\leadsto \frac{\color{blue}{\frac{y \cdot y + \left(\left(z \cdot t\right) \cdot \left(z \cdot t\right) + y \cdot \left(z \cdot t\right)\right)}{{y}^{3} - {\left(z \cdot t\right)}^{3}}}}{\frac{1}{x}} \]
      8. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{y \cdot y + \left(\left(z \cdot t\right) \cdot \left(z \cdot t\right) + y \cdot \left(z \cdot t\right)\right)}{{y}^{3} - {\left(z \cdot t\right)}^{3}}}{\frac{1}{x}}} \]
      9. clear-numN/A

        \[\leadsto \frac{\color{blue}{\frac{1}{\frac{{y}^{3} - {\left(z \cdot t\right)}^{3}}{y \cdot y + \left(\left(z \cdot t\right) \cdot \left(z \cdot t\right) + y \cdot \left(z \cdot t\right)\right)}}}}{\frac{1}{x}} \]
      10. flip3--N/A

        \[\leadsto \frac{\frac{1}{\color{blue}{y - z \cdot t}}}{\frac{1}{x}} \]
      11. lift--.f64N/A

        \[\leadsto \frac{\frac{1}{\color{blue}{y - z \cdot t}}}{\frac{1}{x}} \]
      12. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{1}{y - z \cdot t}}}{\frac{1}{x}} \]
      13. lower-/.f6469.6

        \[\leadsto \frac{\frac{1}{y - z \cdot t}}{\color{blue}{\frac{1}{x}}} \]
    4. Applied rewrites69.6%

      \[\leadsto \color{blue}{\frac{\frac{1}{y - z \cdot t}}{\frac{1}{x}}} \]
    5. Taylor expanded in y around 0

      \[\leadsto \frac{\color{blue}{\frac{-1}{t \cdot z}}}{\frac{1}{x}} \]
    6. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{-1}{t \cdot z}}}{\frac{1}{x}} \]
      2. lower-*.f6469.6

        \[\leadsto \frac{\frac{-1}{\color{blue}{t \cdot z}}}{\frac{1}{x}} \]
    7. Applied rewrites69.6%

      \[\leadsto \frac{\color{blue}{\frac{-1}{t \cdot z}}}{\frac{1}{x}} \]
    8. Taylor expanded in t around inf

      \[\leadsto \color{blue}{\frac{\left(-1 \cdot \frac{x}{z} + -1 \cdot \frac{x \cdot {y}^{2}}{{t}^{2} \cdot {z}^{3}}\right) - \frac{x \cdot y}{t \cdot {z}^{2}}}{t}} \]
    9. Applied rewrites99.7%

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

      \[\leadsto \frac{\frac{x}{z}}{\mathsf{neg}\left(\color{blue}{t}\right)} \]
    11. Step-by-step derivation
      1. Applied rewrites99.7%

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

      if -1.9999999999999999e261 < (*.f64 z t) < 4.00000000000000007e234

      1. Initial program 99.9%

        \[\frac{x}{y - z \cdot t} \]
      2. Add Preprocessing

      if 4.00000000000000007e234 < (*.f64 z t)

      1. Initial program 71.8%

        \[\frac{x}{y - z \cdot t} \]
      2. Add Preprocessing
      3. Taylor expanded in z around inf

        \[\leadsto \color{blue}{\frac{\left(-1 \cdot \frac{x}{t} + -1 \cdot \frac{x \cdot {y}^{2}}{{t}^{3} \cdot {z}^{2}}\right) - \frac{x \cdot y}{{t}^{2} \cdot z}}{z}} \]
      4. Applied rewrites99.9%

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

        \[\leadsto \frac{\frac{x}{t}}{\mathsf{neg}\left(\color{blue}{z}\right)} \]
      6. Step-by-step derivation
        1. Applied rewrites99.9%

          \[\leadsto \frac{\frac{x}{t}}{-\color{blue}{z}} \]
      7. Recombined 3 regimes into one program.
      8. Add Preprocessing

      Alternative 2: 99.7% accurate, 0.4× speedup?

      \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} t_1 := \frac{\frac{x}{t}}{-z}\\ \mathbf{if}\;z \cdot t \leq -\infty:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;z \cdot t \leq 4 \cdot 10^{+234}:\\ \;\;\;\;\frac{x}{y - z \cdot t}\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
      NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
      (FPCore (x y z t)
       :precision binary64
       (let* ((t_1 (/ (/ x t) (- z))))
         (if (<= (* z t) (- INFINITY))
           t_1
           (if (<= (* z t) 4e+234) (/ x (- y (* z t))) t_1))))
      assert(x < y && y < z && z < t);
      double code(double x, double y, double z, double t) {
      	double t_1 = (x / t) / -z;
      	double tmp;
      	if ((z * t) <= -((double) INFINITY)) {
      		tmp = t_1;
      	} else if ((z * t) <= 4e+234) {
      		tmp = x / (y - (z * t));
      	} else {
      		tmp = t_1;
      	}
      	return tmp;
      }
      
      assert x < y && y < z && z < t;
      public static double code(double x, double y, double z, double t) {
      	double t_1 = (x / t) / -z;
      	double tmp;
      	if ((z * t) <= -Double.POSITIVE_INFINITY) {
      		tmp = t_1;
      	} else if ((z * t) <= 4e+234) {
      		tmp = x / (y - (z * t));
      	} else {
      		tmp = t_1;
      	}
      	return tmp;
      }
      
      [x, y, z, t] = sort([x, y, z, t])
      def code(x, y, z, t):
      	t_1 = (x / t) / -z
      	tmp = 0
      	if (z * t) <= -math.inf:
      		tmp = t_1
      	elif (z * t) <= 4e+234:
      		tmp = x / (y - (z * t))
      	else:
      		tmp = t_1
      	return tmp
      
      x, y, z, t = sort([x, y, z, t])
      function code(x, y, z, t)
      	t_1 = Float64(Float64(x / t) / Float64(-z))
      	tmp = 0.0
      	if (Float64(z * t) <= Float64(-Inf))
      		tmp = t_1;
      	elseif (Float64(z * t) <= 4e+234)
      		tmp = Float64(x / Float64(y - Float64(z * t)));
      	else
      		tmp = t_1;
      	end
      	return tmp
      end
      
      x, y, z, t = num2cell(sort([x, y, z, t])){:}
      function tmp_2 = code(x, y, z, t)
      	t_1 = (x / t) / -z;
      	tmp = 0.0;
      	if ((z * t) <= -Inf)
      		tmp = t_1;
      	elseif ((z * t) <= 4e+234)
      		tmp = x / (y - (z * t));
      	else
      		tmp = t_1;
      	end
      	tmp_2 = tmp;
      end
      
      NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
      code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(x / t), $MachinePrecision] / (-z)), $MachinePrecision]}, If[LessEqual[N[(z * t), $MachinePrecision], (-Infinity)], t$95$1, If[LessEqual[N[(z * t), $MachinePrecision], 4e+234], N[(x / N[(y - N[(z * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
      
      \begin{array}{l}
      [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
      \\
      \begin{array}{l}
      t_1 := \frac{\frac{x}{t}}{-z}\\
      \mathbf{if}\;z \cdot t \leq -\infty:\\
      \;\;\;\;t\_1\\
      
      \mathbf{elif}\;z \cdot t \leq 4 \cdot 10^{+234}:\\
      \;\;\;\;\frac{x}{y - z \cdot t}\\
      
      \mathbf{else}:\\
      \;\;\;\;t\_1\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (*.f64 z t) < -inf.0 or 4.00000000000000007e234 < (*.f64 z t)

        1. Initial program 67.8%

          \[\frac{x}{y - z \cdot t} \]
        2. Add Preprocessing
        3. Taylor expanded in z around inf

          \[\leadsto \color{blue}{\frac{\left(-1 \cdot \frac{x}{t} + -1 \cdot \frac{x \cdot {y}^{2}}{{t}^{3} \cdot {z}^{2}}\right) - \frac{x \cdot y}{{t}^{2} \cdot z}}{z}} \]
        4. Applied rewrites99.9%

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

          \[\leadsto \frac{\frac{x}{t}}{\mathsf{neg}\left(\color{blue}{z}\right)} \]
        6. Step-by-step derivation
          1. Applied rewrites99.9%

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

          if -inf.0 < (*.f64 z t) < 4.00000000000000007e234

          1. Initial program 99.8%

            \[\frac{x}{y - z \cdot t} \]
          2. Add Preprocessing
        7. Recombined 2 regimes into one program.
        8. Add Preprocessing

        Alternative 3: 77.0% accurate, 0.5× speedup?

        \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} t_1 := \frac{x}{-z \cdot t}\\ \mathbf{if}\;z \cdot t \leq -5000000000000:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;z \cdot t \leq 5 \cdot 10^{-40}:\\ \;\;\;\;\frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        (FPCore (x y z t)
         :precision binary64
         (let* ((t_1 (/ x (- (* z t)))))
           (if (<= (* z t) -5000000000000.0) t_1 (if (<= (* z t) 5e-40) (/ x y) t_1))))
        assert(x < y && y < z && z < t);
        double code(double x, double y, double z, double t) {
        	double t_1 = x / -(z * t);
        	double tmp;
        	if ((z * t) <= -5000000000000.0) {
        		tmp = t_1;
        	} else if ((z * t) <= 5e-40) {
        		tmp = x / y;
        	} else {
        		tmp = t_1;
        	}
        	return tmp;
        }
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        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 = x / -(z * t)
            if ((z * t) <= (-5000000000000.0d0)) then
                tmp = t_1
            else if ((z * t) <= 5d-40) then
                tmp = x / y
            else
                tmp = t_1
            end if
            code = tmp
        end function
        
        assert x < y && y < z && z < t;
        public static double code(double x, double y, double z, double t) {
        	double t_1 = x / -(z * t);
        	double tmp;
        	if ((z * t) <= -5000000000000.0) {
        		tmp = t_1;
        	} else if ((z * t) <= 5e-40) {
        		tmp = x / y;
        	} else {
        		tmp = t_1;
        	}
        	return tmp;
        }
        
        [x, y, z, t] = sort([x, y, z, t])
        def code(x, y, z, t):
        	t_1 = x / -(z * t)
        	tmp = 0
        	if (z * t) <= -5000000000000.0:
        		tmp = t_1
        	elif (z * t) <= 5e-40:
        		tmp = x / y
        	else:
        		tmp = t_1
        	return tmp
        
        x, y, z, t = sort([x, y, z, t])
        function code(x, y, z, t)
        	t_1 = Float64(x / Float64(-Float64(z * t)))
        	tmp = 0.0
        	if (Float64(z * t) <= -5000000000000.0)
        		tmp = t_1;
        	elseif (Float64(z * t) <= 5e-40)
        		tmp = Float64(x / y);
        	else
        		tmp = t_1;
        	end
        	return tmp
        end
        
        x, y, z, t = num2cell(sort([x, y, z, t])){:}
        function tmp_2 = code(x, y, z, t)
        	t_1 = x / -(z * t);
        	tmp = 0.0;
        	if ((z * t) <= -5000000000000.0)
        		tmp = t_1;
        	elseif ((z * t) <= 5e-40)
        		tmp = x / y;
        	else
        		tmp = t_1;
        	end
        	tmp_2 = tmp;
        end
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        code[x_, y_, z_, t_] := Block[{t$95$1 = N[(x / (-N[(z * t), $MachinePrecision])), $MachinePrecision]}, If[LessEqual[N[(z * t), $MachinePrecision], -5000000000000.0], t$95$1, If[LessEqual[N[(z * t), $MachinePrecision], 5e-40], N[(x / y), $MachinePrecision], t$95$1]]]
        
        \begin{array}{l}
        [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
        \\
        \begin{array}{l}
        t_1 := \frac{x}{-z \cdot t}\\
        \mathbf{if}\;z \cdot t \leq -5000000000000:\\
        \;\;\;\;t\_1\\
        
        \mathbf{elif}\;z \cdot t \leq 5 \cdot 10^{-40}:\\
        \;\;\;\;\frac{x}{y}\\
        
        \mathbf{else}:\\
        \;\;\;\;t\_1\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (*.f64 z t) < -5e12 or 4.99999999999999965e-40 < (*.f64 z t)

          1. Initial program 90.6%

            \[\frac{x}{y - z \cdot t} \]
          2. Add Preprocessing
          3. Taylor expanded in y around 0

            \[\leadsto \frac{x}{\color{blue}{-1 \cdot \left(t \cdot z\right)}} \]
          4. Step-by-step derivation
            1. mul-1-negN/A

              \[\leadsto \frac{x}{\color{blue}{\mathsf{neg}\left(t \cdot z\right)}} \]
            2. distribute-rgt-neg-inN/A

              \[\leadsto \frac{x}{\color{blue}{t \cdot \left(\mathsf{neg}\left(z\right)\right)}} \]
            3. mul-1-negN/A

              \[\leadsto \frac{x}{t \cdot \color{blue}{\left(-1 \cdot z\right)}} \]
            4. lower-*.f64N/A

              \[\leadsto \frac{x}{\color{blue}{t \cdot \left(-1 \cdot z\right)}} \]
            5. mul-1-negN/A

              \[\leadsto \frac{x}{t \cdot \color{blue}{\left(\mathsf{neg}\left(z\right)\right)}} \]
            6. lower-neg.f6474.6

              \[\leadsto \frac{x}{t \cdot \color{blue}{\left(-z\right)}} \]
          5. Applied rewrites74.6%

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

          if -5e12 < (*.f64 z t) < 4.99999999999999965e-40

          1. Initial program 100.0%

            \[\frac{x}{y - z \cdot t} \]
          2. Add Preprocessing
          3. Taylor expanded in y around inf

            \[\leadsto \color{blue}{\frac{x}{y}} \]
          4. Step-by-step derivation
            1. lower-/.f6487.9

              \[\leadsto \color{blue}{\frac{x}{y}} \]
          5. Applied rewrites87.9%

            \[\leadsto \color{blue}{\frac{x}{y}} \]
        3. Recombined 2 regimes into one program.
        4. Final simplification80.8%

          \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot t \leq -5000000000000:\\ \;\;\;\;\frac{x}{-z \cdot t}\\ \mathbf{elif}\;z \cdot t \leq 5 \cdot 10^{-40}:\\ \;\;\;\;\frac{x}{y}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{-z \cdot t}\\ \end{array} \]
        5. Add Preprocessing

        Alternative 4: 95.8% accurate, 1.0× speedup?

        \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \frac{x}{y - z \cdot t} \end{array} \]
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        (FPCore (x y z t) :precision binary64 (/ x (- y (* z t))))
        assert(x < y && y < z && z < t);
        double code(double x, double y, double z, double t) {
        	return x / (y - (z * t));
        }
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        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 - (z * t))
        end function
        
        assert x < y && y < z && z < t;
        public static double code(double x, double y, double z, double t) {
        	return x / (y - (z * t));
        }
        
        [x, y, z, t] = sort([x, y, z, t])
        def code(x, y, z, t):
        	return x / (y - (z * t))
        
        x, y, z, t = sort([x, y, z, t])
        function code(x, y, z, t)
        	return Float64(x / Float64(y - Float64(z * t)))
        end
        
        x, y, z, t = num2cell(sort([x, y, z, t])){:}
        function tmp = code(x, y, z, t)
        	tmp = x / (y - (z * t));
        end
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        code[x_, y_, z_, t_] := N[(x / N[(y - N[(z * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
        \\
        \frac{x}{y - z \cdot t}
        \end{array}
        
        Derivation
        1. Initial program 95.0%

          \[\frac{x}{y - z \cdot t} \]
        2. Add Preprocessing
        3. Add Preprocessing

        Alternative 5: 54.2% accurate, 1.7× speedup?

        \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \frac{x}{y} \end{array} \]
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        (FPCore (x y z t) :precision binary64 (/ x y))
        assert(x < y && y < z && z < t);
        double code(double x, double y, double z, double t) {
        	return x / y;
        }
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        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
        end function
        
        assert x < y && y < z && z < t;
        public static double code(double x, double y, double z, double t) {
        	return x / y;
        }
        
        [x, y, z, t] = sort([x, y, z, t])
        def code(x, y, z, t):
        	return x / y
        
        x, y, z, t = sort([x, y, z, t])
        function code(x, y, z, t)
        	return Float64(x / y)
        end
        
        x, y, z, t = num2cell(sort([x, y, z, t])){:}
        function tmp = code(x, y, z, t)
        	tmp = x / y;
        end
        
        NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
        code[x_, y_, z_, t_] := N[(x / y), $MachinePrecision]
        
        \begin{array}{l}
        [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
        \\
        \frac{x}{y}
        \end{array}
        
        Derivation
        1. Initial program 95.0%

          \[\frac{x}{y - z \cdot t} \]
        2. Add Preprocessing
        3. Taylor expanded in y around inf

          \[\leadsto \color{blue}{\frac{x}{y}} \]
        4. Step-by-step derivation
          1. lower-/.f6453.9

            \[\leadsto \color{blue}{\frac{x}{y}} \]
        5. Applied rewrites53.9%

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

        Developer Target 1: 96.5% accurate, 0.4× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{1}{\frac{y}{x} - \frac{z}{x} \cdot t}\\ \mathbf{if}\;x < -1.618195973607049 \cdot 10^{+50}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;x < 2.1378306434876444 \cdot 10^{+131}:\\ \;\;\;\;\frac{x}{y - z \cdot t}\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
        (FPCore (x y z t)
         :precision binary64
         (let* ((t_1 (/ 1.0 (- (/ y x) (* (/ z x) t)))))
           (if (< x -1.618195973607049e+50)
             t_1
             (if (< x 2.1378306434876444e+131) (/ x (- y (* z t))) t_1))))
        double code(double x, double y, double z, double t) {
        	double t_1 = 1.0 / ((y / x) - ((z / x) * t));
        	double tmp;
        	if (x < -1.618195973607049e+50) {
        		tmp = t_1;
        	} else if (x < 2.1378306434876444e+131) {
        		tmp = x / (y - (z * t));
        	} else {
        		tmp = t_1;
        	}
        	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 = 1.0d0 / ((y / x) - ((z / x) * t))
            if (x < (-1.618195973607049d+50)) then
                tmp = t_1
            else if (x < 2.1378306434876444d+131) then
                tmp = x / (y - (z * t))
            else
                tmp = t_1
            end if
            code = tmp
        end function
        
        public static double code(double x, double y, double z, double t) {
        	double t_1 = 1.0 / ((y / x) - ((z / x) * t));
        	double tmp;
        	if (x < -1.618195973607049e+50) {
        		tmp = t_1;
        	} else if (x < 2.1378306434876444e+131) {
        		tmp = x / (y - (z * t));
        	} else {
        		tmp = t_1;
        	}
        	return tmp;
        }
        
        def code(x, y, z, t):
        	t_1 = 1.0 / ((y / x) - ((z / x) * t))
        	tmp = 0
        	if x < -1.618195973607049e+50:
        		tmp = t_1
        	elif x < 2.1378306434876444e+131:
        		tmp = x / (y - (z * t))
        	else:
        		tmp = t_1
        	return tmp
        
        function code(x, y, z, t)
        	t_1 = Float64(1.0 / Float64(Float64(y / x) - Float64(Float64(z / x) * t)))
        	tmp = 0.0
        	if (x < -1.618195973607049e+50)
        		tmp = t_1;
        	elseif (x < 2.1378306434876444e+131)
        		tmp = Float64(x / Float64(y - Float64(z * t)));
        	else
        		tmp = t_1;
        	end
        	return tmp
        end
        
        function tmp_2 = code(x, y, z, t)
        	t_1 = 1.0 / ((y / x) - ((z / x) * t));
        	tmp = 0.0;
        	if (x < -1.618195973607049e+50)
        		tmp = t_1;
        	elseif (x < 2.1378306434876444e+131)
        		tmp = x / (y - (z * t));
        	else
        		tmp = t_1;
        	end
        	tmp_2 = tmp;
        end
        
        code[x_, y_, z_, t_] := Block[{t$95$1 = N[(1.0 / N[(N[(y / x), $MachinePrecision] - N[(N[(z / x), $MachinePrecision] * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[Less[x, -1.618195973607049e+50], t$95$1, If[Less[x, 2.1378306434876444e+131], N[(x / N[(y - N[(z * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_1 := \frac{1}{\frac{y}{x} - \frac{z}{x} \cdot t}\\
        \mathbf{if}\;x < -1.618195973607049 \cdot 10^{+50}:\\
        \;\;\;\;t\_1\\
        
        \mathbf{elif}\;x < 2.1378306434876444 \cdot 10^{+131}:\\
        \;\;\;\;\frac{x}{y - z \cdot t}\\
        
        \mathbf{else}:\\
        \;\;\;\;t\_1\\
        
        
        \end{array}
        \end{array}
        

        Reproduce

        ?
        herbie shell --seed 2024220 
        (FPCore (x y z t)
          :name "Diagrams.Solve.Tridiagonal:solveTriDiagonal from diagrams-solve-0.1, B"
          :precision binary64
        
          :alt
          (! :herbie-platform default (if (< x -161819597360704900000000000000000000000000000000000) (/ 1 (- (/ y x) (* (/ z x) t))) (if (< x 213783064348764440000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (/ x (- y (* z t))) (/ 1 (- (/ y x) (* (/ z x) t))))))
        
          (/ x (- y (* z t))))