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

Percentage Accurate: 96.0% → 99.4%
Time: 5.4s
Alternatives: 6
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 6 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 96.0% 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: 99.4% accurate, 0.4× speedup?

\[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} \mathbf{if}\;z \cdot t \leq -1 \cdot 10^{+217} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\ \;\;\;\;\frac{\frac{-x}{t}}{z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\mathsf{fma}\left(-z, t, y\right)}\\ \end{array} \end{array} \]
NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
(FPCore (x y z t)
 :precision binary64
 (if (or (<= (* z t) -1e+217) (not (<= (* z t) 1e+213)))
   (/ (/ (- x) t) z)
   (/ x (fma (- z) t y))))
assert(x < y && y < z && z < t);
double code(double x, double y, double z, double t) {
	double tmp;
	if (((z * t) <= -1e+217) || !((z * t) <= 1e+213)) {
		tmp = (-x / t) / z;
	} else {
		tmp = x / fma(-z, t, y);
	}
	return tmp;
}
x, y, z, t = sort([x, y, z, t])
function code(x, y, z, t)
	tmp = 0.0
	if ((Float64(z * t) <= -1e+217) || !(Float64(z * t) <= 1e+213))
		tmp = Float64(Float64(Float64(-x) / t) / z);
	else
		tmp = Float64(x / fma(Float64(-z), t, y));
	end
	return tmp
end
NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z * t), $MachinePrecision], -1e+217], N[Not[LessEqual[N[(z * t), $MachinePrecision], 1e+213]], $MachinePrecision]], N[(N[((-x) / t), $MachinePrecision] / z), $MachinePrecision], N[(x / N[((-z) * t + y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
\\
\begin{array}{l}
\mathbf{if}\;z \cdot t \leq -1 \cdot 10^{+217} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\
\;\;\;\;\frac{\frac{-x}{t}}{z}\\

\mathbf{else}:\\
\;\;\;\;\frac{x}{\mathsf{fma}\left(-z, t, y\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 z t) < -9.9999999999999996e216 or 9.99999999999999984e212 < (*.f64 z t)

    1. Initial program 71.3%

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

      \[\leadsto \color{blue}{-1 \cdot \frac{x}{t \cdot z}} \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{-1 \cdot x}{t \cdot z}} \]
      2. associate-/l/N/A

        \[\leadsto \color{blue}{\frac{\frac{-1 \cdot x}{z}}{t}} \]
      3. associate-*r/N/A

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

        \[\leadsto \color{blue}{\frac{-1 \cdot \frac{x}{z}}{t}} \]
      5. associate-*r/N/A

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

        \[\leadsto \frac{\color{blue}{\frac{-1 \cdot x}{z}}}{t} \]
      7. mul-1-negN/A

        \[\leadsto \frac{\frac{\color{blue}{\mathsf{neg}\left(x\right)}}{z}}{t} \]
      8. lower-neg.f6499.9

        \[\leadsto \frac{\frac{\color{blue}{-x}}{z}}{t} \]
    5. Applied rewrites99.9%

      \[\leadsto \color{blue}{\frac{\frac{-x}{z}}{t}} \]
    6. Step-by-step derivation
      1. Applied rewrites99.8%

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

      if -9.9999999999999996e216 < (*.f64 z t) < 9.99999999999999984e212

      1. Initial program 99.9%

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

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

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

          \[\leadsto \frac{x}{\color{blue}{\left(\mathsf{neg}\left(z \cdot t\right)\right) + y}} \]
        4. lift-*.f64N/A

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

          \[\leadsto \frac{x}{\color{blue}{\left(\mathsf{neg}\left(z\right)\right) \cdot t} + y} \]
        6. lower-fma.f64N/A

          \[\leadsto \frac{x}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(z\right), t, y\right)}} \]
        7. lower-neg.f6499.9

          \[\leadsto \frac{x}{\mathsf{fma}\left(\color{blue}{-z}, t, y\right)} \]
      4. Applied rewrites99.9%

        \[\leadsto \frac{x}{\color{blue}{\mathsf{fma}\left(-z, t, y\right)}} \]
    7. Recombined 2 regimes into one program.
    8. Final simplification99.8%

      \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot t \leq -1 \cdot 10^{+217} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\ \;\;\;\;\frac{\frac{-x}{t}}{z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\mathsf{fma}\left(-z, t, y\right)}\\ \end{array} \]
    9. Add Preprocessing

    Alternative 2: 77.1% accurate, 0.5× speedup?

    \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} \mathbf{if}\;z \cdot t \leq -1 \cdot 10^{-62} \lor \neg \left(z \cdot t \leq 400\right):\\ \;\;\;\;\frac{x}{\left(-z\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{y}\\ \end{array} \end{array} \]
    NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
    (FPCore (x y z t)
     :precision binary64
     (if (or (<= (* z t) -1e-62) (not (<= (* z t) 400.0)))
       (/ x (* (- z) t))
       (/ x y)))
    assert(x < y && y < z && z < t);
    double code(double x, double y, double z, double t) {
    	double tmp;
    	if (((z * t) <= -1e-62) || !((z * t) <= 400.0)) {
    		tmp = x / (-z * t);
    	} else {
    		tmp = x / y;
    	}
    	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) <= (-1d-62)) .or. (.not. ((z * t) <= 400.0d0))) then
            tmp = x / (-z * t)
        else
            tmp = x / y
        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) <= -1e-62) || !((z * t) <= 400.0)) {
    		tmp = x / (-z * t);
    	} else {
    		tmp = x / y;
    	}
    	return tmp;
    }
    
    [x, y, z, t] = sort([x, y, z, t])
    def code(x, y, z, t):
    	tmp = 0
    	if ((z * t) <= -1e-62) or not ((z * t) <= 400.0):
    		tmp = x / (-z * t)
    	else:
    		tmp = x / y
    	return tmp
    
    x, y, z, t = sort([x, y, z, t])
    function code(x, y, z, t)
    	tmp = 0.0
    	if ((Float64(z * t) <= -1e-62) || !(Float64(z * t) <= 400.0))
    		tmp = Float64(x / Float64(Float64(-z) * t));
    	else
    		tmp = Float64(x / y);
    	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) <= -1e-62) || ~(((z * t) <= 400.0)))
    		tmp = x / (-z * t);
    	else
    		tmp = x / y;
    	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[Or[LessEqual[N[(z * t), $MachinePrecision], -1e-62], N[Not[LessEqual[N[(z * t), $MachinePrecision], 400.0]], $MachinePrecision]], N[(x / N[((-z) * t), $MachinePrecision]), $MachinePrecision], N[(x / y), $MachinePrecision]]
    
    \begin{array}{l}
    [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
    \\
    \begin{array}{l}
    \mathbf{if}\;z \cdot t \leq -1 \cdot 10^{-62} \lor \neg \left(z \cdot t \leq 400\right):\\
    \;\;\;\;\frac{x}{\left(-z\right) \cdot t}\\
    
    \mathbf{else}:\\
    \;\;\;\;\frac{x}{y}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (*.f64 z t) < -1e-62 or 400 < (*.f64 z t)

      1. Initial program 86.7%

        \[\frac{x}{y - z \cdot t} \]
      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. *-commutativeN/A

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

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

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

          \[\leadsto \frac{x}{\color{blue}{\left(\mathsf{neg}\left(z\right)\right)} \cdot t} \]
        5. lower-neg.f6469.5

          \[\leadsto \frac{x}{\color{blue}{\left(-z\right)} \cdot t} \]
      5. Applied rewrites69.5%

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

      if -1e-62 < (*.f64 z t) < 400

      1. Initial program 99.9%

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

        \[\leadsto \color{blue}{\frac{x}{y}} \]
      4. Step-by-step derivation
        1. lower-/.f6488.3

          \[\leadsto \color{blue}{\frac{x}{y}} \]
      5. Applied rewrites88.3%

        \[\leadsto \color{blue}{\frac{x}{y}} \]
    3. Recombined 2 regimes into one program.
    4. Final simplification78.2%

      \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot t \leq -1 \cdot 10^{-62} \lor \neg \left(z \cdot t \leq 400\right):\\ \;\;\;\;\frac{x}{\left(-z\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{y}\\ \end{array} \]
    5. Add Preprocessing

    Alternative 3: 64.3% accurate, 0.5× speedup?

    \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \begin{array}{l} \mathbf{if}\;z \cdot t \leq -2 \cdot 10^{+203} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\ \;\;\;\;\frac{x}{t \cdot z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{y}\\ \end{array} \end{array} \]
    NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
    (FPCore (x y z t)
     :precision binary64
     (if (or (<= (* z t) -2e+203) (not (<= (* z t) 1e+213)))
       (/ x (* t z))
       (/ x y)))
    assert(x < y && y < z && z < t);
    double code(double x, double y, double z, double t) {
    	double tmp;
    	if (((z * t) <= -2e+203) || !((z * t) <= 1e+213)) {
    		tmp = x / (t * z);
    	} else {
    		tmp = x / y;
    	}
    	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+203)) .or. (.not. ((z * t) <= 1d+213))) then
            tmp = x / (t * z)
        else
            tmp = x / y
        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+203) || !((z * t) <= 1e+213)) {
    		tmp = x / (t * z);
    	} else {
    		tmp = x / y;
    	}
    	return tmp;
    }
    
    [x, y, z, t] = sort([x, y, z, t])
    def code(x, y, z, t):
    	tmp = 0
    	if ((z * t) <= -2e+203) or not ((z * t) <= 1e+213):
    		tmp = x / (t * z)
    	else:
    		tmp = x / y
    	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+203) || !(Float64(z * t) <= 1e+213))
    		tmp = Float64(x / Float64(t * z));
    	else
    		tmp = Float64(x / y);
    	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+203) || ~(((z * t) <= 1e+213)))
    		tmp = x / (t * z);
    	else
    		tmp = x / y;
    	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[Or[LessEqual[N[(z * t), $MachinePrecision], -2e+203], N[Not[LessEqual[N[(z * t), $MachinePrecision], 1e+213]], $MachinePrecision]], N[(x / N[(t * z), $MachinePrecision]), $MachinePrecision], N[(x / y), $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^{+203} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\
    \;\;\;\;\frac{x}{t \cdot z}\\
    
    \mathbf{else}:\\
    \;\;\;\;\frac{x}{y}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (*.f64 z t) < -2e203 or 9.99999999999999984e212 < (*.f64 z t)

      1. Initial program 73.0%

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

        \[\leadsto \color{blue}{-1 \cdot \frac{x}{t \cdot z}} \]
      4. Step-by-step derivation
        1. associate-*r/N/A

          \[\leadsto \color{blue}{\frac{-1 \cdot x}{t \cdot z}} \]
        2. associate-/l/N/A

          \[\leadsto \color{blue}{\frac{\frac{-1 \cdot x}{z}}{t}} \]
        3. associate-*r/N/A

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

          \[\leadsto \color{blue}{\frac{-1 \cdot \frac{x}{z}}{t}} \]
        5. associate-*r/N/A

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

          \[\leadsto \frac{\color{blue}{\frac{-1 \cdot x}{z}}}{t} \]
        7. mul-1-negN/A

          \[\leadsto \frac{\frac{\color{blue}{\mathsf{neg}\left(x\right)}}{z}}{t} \]
        8. lower-neg.f6499.9

          \[\leadsto \frac{\frac{\color{blue}{-x}}{z}}{t} \]
      5. Applied rewrites99.9%

        \[\leadsto \color{blue}{\frac{\frac{-x}{z}}{t}} \]
      6. Step-by-step derivation
        1. Applied rewrites72.9%

          \[\leadsto x \cdot \color{blue}{\frac{1}{t \cdot \left(-z\right)}} \]
        2. Step-by-step derivation
          1. Applied rewrites73.3%

            \[\leadsto x \cdot \frac{\frac{-1}{z}}{\color{blue}{t}} \]
          2. Step-by-step derivation
            1. Applied rewrites47.8%

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

            if -2e203 < (*.f64 z t) < 9.99999999999999984e212

            1. Initial program 99.9%

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

              \[\leadsto \color{blue}{\frac{x}{y}} \]
            4. Step-by-step derivation
              1. lower-/.f6470.2

                \[\leadsto \color{blue}{\frac{x}{y}} \]
            5. Applied rewrites70.2%

              \[\leadsto \color{blue}{\frac{x}{y}} \]
          3. Recombined 2 regimes into one program.
          4. Final simplification64.3%

            \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot t \leq -2 \cdot 10^{+203} \lor \neg \left(z \cdot t \leq 10^{+213}\right):\\ \;\;\;\;\frac{x}{t \cdot z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{y}\\ \end{array} \]
          5. Add Preprocessing

          Alternative 4: 96.0% accurate, 1.0× speedup?

          \[\begin{array}{l} [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\ \\ \frac{x}{\mathsf{fma}\left(-z, t, y\right)} \end{array} \]
          NOTE: x, y, z, and t should be sorted in increasing order before calling this function.
          (FPCore (x y z t) :precision binary64 (/ x (fma (- z) t y)))
          assert(x < y && y < z && z < t);
          double code(double x, double y, double z, double t) {
          	return x / fma(-z, t, y);
          }
          
          x, y, z, t = sort([x, y, z, t])
          function code(x, y, z, t)
          	return Float64(x / fma(Float64(-z), t, 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 / N[((-z) * t + y), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          [x, y, z, t] = \mathsf{sort}([x, y, z, t])\\
          \\
          \frac{x}{\mathsf{fma}\left(-z, t, y\right)}
          \end{array}
          
          Derivation
          1. Initial program 92.8%

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

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

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

              \[\leadsto \frac{x}{\color{blue}{\left(\mathsf{neg}\left(z \cdot t\right)\right) + y}} \]
            4. lift-*.f64N/A

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

              \[\leadsto \frac{x}{\color{blue}{\left(\mathsf{neg}\left(z\right)\right) \cdot t} + y} \]
            6. lower-fma.f64N/A

              \[\leadsto \frac{x}{\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(z\right), t, y\right)}} \]
            7. lower-neg.f6492.8

              \[\leadsto \frac{x}{\mathsf{fma}\left(\color{blue}{-z}, t, y\right)} \]
          4. Applied rewrites92.8%

            \[\leadsto \frac{x}{\color{blue}{\mathsf{fma}\left(-z, t, y\right)}} \]
          5. Add Preprocessing

          Alternative 5: 96.0% 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 92.8%

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

          Alternative 6: 55.5% 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 92.8%

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

            \[\leadsto \color{blue}{\frac{x}{y}} \]
          4. Step-by-step derivation
            1. lower-/.f6454.5

              \[\leadsto \color{blue}{\frac{x}{y}} \]
          5. Applied rewrites54.5%

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

          Developer Target 1: 96.6% 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 2024318 
          (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))))