Kahan p13 Example 1

Percentage Accurate: 99.9% → 99.9%
Time: 7.9s
Alternatives: 7
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2 \cdot t}{1 + t}\\ t_2 := t\_1 \cdot t\_1\\ \frac{1 + t\_2}{2 + t\_2} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (/ (* 2.0 t) (+ 1.0 t))) (t_2 (* t_1 t_1)))
   (/ (+ 1.0 t_2) (+ 2.0 t_2))))
double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: t_2
    t_1 = (2.0d0 * t) / (1.0d0 + t)
    t_2 = t_1 * t_1
    code = (1.0d0 + t_2) / (2.0d0 + t_2)
end function
public static double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
def code(t):
	t_1 = (2.0 * t) / (1.0 + t)
	t_2 = t_1 * t_1
	return (1.0 + t_2) / (2.0 + t_2)
function code(t)
	t_1 = Float64(Float64(2.0 * t) / Float64(1.0 + t))
	t_2 = Float64(t_1 * t_1)
	return Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2))
end
function tmp = code(t)
	t_1 = (2.0 * t) / (1.0 + t);
	t_2 = t_1 * t_1;
	tmp = (1.0 + t_2) / (2.0 + t_2);
end
code[t_] := Block[{t$95$1 = N[(N[(2.0 * t), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{2 \cdot t}{1 + t}\\
t_2 := t\_1 \cdot t\_1\\
\frac{1 + t\_2}{2 + t\_2}
\end{array}
\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 7 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: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2 \cdot t}{1 + t}\\ t_2 := t\_1 \cdot t\_1\\ \frac{1 + t\_2}{2 + t\_2} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (/ (* 2.0 t) (+ 1.0 t))) (t_2 (* t_1 t_1)))
   (/ (+ 1.0 t_2) (+ 2.0 t_2))))
double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: t_2
    t_1 = (2.0d0 * t) / (1.0d0 + t)
    t_2 = t_1 * t_1
    code = (1.0d0 + t_2) / (2.0d0 + t_2)
end function
public static double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
def code(t):
	t_1 = (2.0 * t) / (1.0 + t)
	t_2 = t_1 * t_1
	return (1.0 + t_2) / (2.0 + t_2)
function code(t)
	t_1 = Float64(Float64(2.0 * t) / Float64(1.0 + t))
	t_2 = Float64(t_1 * t_1)
	return Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2))
end
function tmp = code(t)
	t_1 = (2.0 * t) / (1.0 + t);
	t_2 = t_1 * t_1;
	tmp = (1.0 + t_2) / (2.0 + t_2);
end
code[t_] := Block[{t$95$1 = N[(N[(2.0 * t), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{2 \cdot t}{1 + t}\\
t_2 := t\_1 \cdot t\_1\\
\frac{1 + t\_2}{2 + t\_2}
\end{array}
\end{array}

Alternative 1: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2 \cdot t}{1 + t}\\ t_2 := t\_1 \cdot t\_1\\ \frac{1 + t\_2}{2 + t\_2} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (/ (* 2.0 t) (+ 1.0 t))) (t_2 (* t_1 t_1)))
   (/ (+ 1.0 t_2) (+ 2.0 t_2))))
double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: t_2
    t_1 = (2.0d0 * t) / (1.0d0 + t)
    t_2 = t_1 * t_1
    code = (1.0d0 + t_2) / (2.0d0 + t_2)
end function
public static double code(double t) {
	double t_1 = (2.0 * t) / (1.0 + t);
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
def code(t):
	t_1 = (2.0 * t) / (1.0 + t)
	t_2 = t_1 * t_1
	return (1.0 + t_2) / (2.0 + t_2)
function code(t)
	t_1 = Float64(Float64(2.0 * t) / Float64(1.0 + t))
	t_2 = Float64(t_1 * t_1)
	return Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2))
end
function tmp = code(t)
	t_1 = (2.0 * t) / (1.0 + t);
	t_2 = t_1 * t_1;
	tmp = (1.0 + t_2) / (2.0 + t_2);
end
code[t_] := Block[{t$95$1 = N[(N[(2.0 * t), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{2 \cdot t}{1 + t}\\
t_2 := t\_1 \cdot t\_1\\
\frac{1 + t\_2}{2 + t\_2}
\end{array}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
  2. Add Preprocessing
  3. Add Preprocessing

Alternative 2: 100.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -500000000:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 2000000:\\ \;\;\;\;0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (+ 0.8333333333333334 (/ -0.2222222222222222 t))))
   (if (<= t -500000000.0)
     t_1
     (if (<= t 2000000.0)
       (+
        0.5
        (/
         (/ (/ (* t t) (+ 1.0 t)) (+ 1.0 t))
         (+ 1.0 (/ (/ (* 2.0 (* t t)) (+ 1.0 t)) (+ 1.0 t)))))
       t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	double tmp;
	if (t <= -500000000.0) {
		tmp = t_1;
	} else if (t <= 2000000.0) {
		tmp = 0.5 + ((((t * t) / (1.0 + t)) / (1.0 + t)) / (1.0 + (((2.0 * (t * t)) / (1.0 + t)) / (1.0 + t))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + ((-0.2222222222222222d0) / t)
    if (t <= (-500000000.0d0)) then
        tmp = t_1
    else if (t <= 2000000.0d0) then
        tmp = 0.5d0 + ((((t * t) / (1.0d0 + t)) / (1.0d0 + t)) / (1.0d0 + (((2.0d0 * (t * t)) / (1.0d0 + t)) / (1.0d0 + t))))
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	double tmp;
	if (t <= -500000000.0) {
		tmp = t_1;
	} else if (t <= 2000000.0) {
		tmp = 0.5 + ((((t * t) / (1.0 + t)) / (1.0 + t)) / (1.0 + (((2.0 * (t * t)) / (1.0 + t)) / (1.0 + t))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t)
	tmp = 0
	if t <= -500000000.0:
		tmp = t_1
	elif t <= 2000000.0:
		tmp = 0.5 + ((((t * t) / (1.0 + t)) / (1.0 + t)) / (1.0 + (((2.0 * (t * t)) / (1.0 + t)) / (1.0 + t))))
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(-0.2222222222222222 / t))
	tmp = 0.0
	if (t <= -500000000.0)
		tmp = t_1;
	elseif (t <= 2000000.0)
		tmp = Float64(0.5 + Float64(Float64(Float64(Float64(t * t) / Float64(1.0 + t)) / Float64(1.0 + t)) / Float64(1.0 + Float64(Float64(Float64(2.0 * Float64(t * t)) / Float64(1.0 + t)) / Float64(1.0 + t)))));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	tmp = 0.0;
	if (t <= -500000000.0)
		tmp = t_1;
	elseif (t <= 2000000.0)
		tmp = 0.5 + ((((t * t) / (1.0 + t)) / (1.0 + t)) / (1.0 + (((2.0 * (t * t)) / (1.0 + t)) / (1.0 + t))));
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(-0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -500000000.0], t$95$1, If[LessEqual[t, 2000000.0], N[(0.5 + N[(N[(N[(N[(t * t), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[(N[(N[(2.0 * N[(t * t), $MachinePrecision]), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] / N[(1.0 + t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -500000000:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 2000000:\\
\;\;\;\;0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -5e8 or 2e6 < t

    1. Initial program 100.0%

      \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
    2. Simplified56.2%

      \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

      \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
    5. Step-by-step derivation
      1. sub-negN/A

        \[\leadsto \frac{5}{6} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)} \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
      3. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} \cdot 1}{t}\right)\right)\right) \]
      4. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9}}{t}\right)\right)\right) \]
      5. distribute-neg-fracN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{\mathsf{neg}\left(\frac{2}{9}\right)}{\color{blue}{t}}\right)\right) \]
      6. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\mathsf{neg}\left(\frac{2}{9}\right)\right), \color{blue}{t}\right)\right) \]
      7. metadata-eval100.0%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\frac{-2}{9}, t\right)\right) \]
    6. Simplified100.0%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{-0.2222222222222222}{t}} \]

    if -5e8 < t < 2e6

    1. Initial program 100.0%

      \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
    3. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 3: 99.2% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -0.33:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 + \frac{-0.037037037037037035 + \frac{-0.04938271604938271}{t}}{t}}{t}\\ \mathbf{elif}\;t \leq 0.23:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (if (<= t -0.33)
   (-
    0.8333333333333334
    (/
     (+
      0.2222222222222222
      (/ (+ -0.037037037037037035 (/ -0.04938271604938271 t)) t))
     t))
   (if (<= t 0.23)
     0.5
     (+
      0.8333333333333334
      (/ (+ -0.2222222222222222 (/ 0.037037037037037035 t)) t)))))
double code(double t) {
	double tmp;
	if (t <= -0.33) {
		tmp = 0.8333333333333334 - ((0.2222222222222222 + ((-0.037037037037037035 + (-0.04938271604938271 / t)) / t)) / t);
	} else if (t <= 0.23) {
		tmp = 0.5;
	} else {
		tmp = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: tmp
    if (t <= (-0.33d0)) then
        tmp = 0.8333333333333334d0 - ((0.2222222222222222d0 + (((-0.037037037037037035d0) + ((-0.04938271604938271d0) / t)) / t)) / t)
    else if (t <= 0.23d0) then
        tmp = 0.5d0
    else
        tmp = 0.8333333333333334d0 + (((-0.2222222222222222d0) + (0.037037037037037035d0 / t)) / t)
    end if
    code = tmp
end function
public static double code(double t) {
	double tmp;
	if (t <= -0.33) {
		tmp = 0.8333333333333334 - ((0.2222222222222222 + ((-0.037037037037037035 + (-0.04938271604938271 / t)) / t)) / t);
	} else if (t <= 0.23) {
		tmp = 0.5;
	} else {
		tmp = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
	}
	return tmp;
}
def code(t):
	tmp = 0
	if t <= -0.33:
		tmp = 0.8333333333333334 - ((0.2222222222222222 + ((-0.037037037037037035 + (-0.04938271604938271 / t)) / t)) / t)
	elif t <= 0.23:
		tmp = 0.5
	else:
		tmp = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t)
	return tmp
function code(t)
	tmp = 0.0
	if (t <= -0.33)
		tmp = Float64(0.8333333333333334 - Float64(Float64(0.2222222222222222 + Float64(Float64(-0.037037037037037035 + Float64(-0.04938271604938271 / t)) / t)) / t));
	elseif (t <= 0.23)
		tmp = 0.5;
	else
		tmp = Float64(0.8333333333333334 + Float64(Float64(-0.2222222222222222 + Float64(0.037037037037037035 / t)) / t));
	end
	return tmp
end
function tmp_2 = code(t)
	tmp = 0.0;
	if (t <= -0.33)
		tmp = 0.8333333333333334 - ((0.2222222222222222 + ((-0.037037037037037035 + (-0.04938271604938271 / t)) / t)) / t);
	elseif (t <= 0.23)
		tmp = 0.5;
	else
		tmp = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
	end
	tmp_2 = tmp;
end
code[t_] := If[LessEqual[t, -0.33], N[(0.8333333333333334 - N[(N[(0.2222222222222222 + N[(N[(-0.037037037037037035 + N[(-0.04938271604938271 / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision], If[LessEqual[t, 0.23], 0.5, N[(0.8333333333333334 + N[(N[(-0.2222222222222222 + N[(0.037037037037037035 / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq -0.33:\\
\;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 + \frac{-0.037037037037037035 + \frac{-0.04938271604938271}{t}}{t}}{t}\\

\mathbf{elif}\;t \leq 0.23:\\
\;\;\;\;0.5\\

\mathbf{else}:\\
\;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if t < -0.330000000000000016

    1. Initial program 100.0%

      \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
    2. Simplified60.5%

      \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around -inf

      \[\leadsto \color{blue}{\frac{5}{6} + -1 \cdot \frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}} \]
    5. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{5}{6} + \left(\mathsf{neg}\left(\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}\right)\right) \]
      2. unsub-negN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}} \]
      3. --lowering--.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \color{blue}{\left(\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}\right)}\right) \]
      4. /-lowering-/.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}\right), \color{blue}{t}\right)\right) \]
    6. Simplified99.0%

      \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222 + \frac{-0.037037037037037035 + \frac{-0.04938271604938271}{t}}{t}}{t}} \]

    if -0.330000000000000016 < t < 0.23000000000000001

    1. Initial program 100.0%

      \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

      \[\leadsto \color{blue}{\frac{1}{2}} \]
    5. Step-by-step derivation
      1. Simplified100.0%

        \[\leadsto \color{blue}{0.5} \]

      if 0.23000000000000001 < t

      1. Initial program 100.0%

        \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
      2. Simplified53.9%

        \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
      3. Add Preprocessing
      4. Taylor expanded in t around inf

        \[\leadsto \color{blue}{\left(\frac{5}{6} + \frac{\frac{1}{27}}{{t}^{2}}\right) - \frac{2}{9} \cdot \frac{1}{t}} \]
      5. Step-by-step derivation
        1. associate--l+N/A

          \[\leadsto \frac{5}{6} + \color{blue}{\left(\frac{\frac{1}{27}}{{t}^{2}} - \frac{2}{9} \cdot \frac{1}{t}\right)} \]
        2. sub-negN/A

          \[\leadsto \frac{5}{6} + \left(\frac{\frac{1}{27}}{{t}^{2}} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
        3. +-commutativeN/A

          \[\leadsto \frac{5}{6} + \left(\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right) + \color{blue}{\frac{\frac{1}{27}}{{t}^{2}}}\right) \]
        4. +-lowering-+.f64N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right) + \frac{\frac{1}{27}}{{t}^{2}}\right)}\right) \]
        5. neg-sub0N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\left(0 - \frac{2}{9} \cdot \frac{1}{t}\right) + \frac{\color{blue}{\frac{1}{27}}}{{t}^{2}}\right)\right) \]
        6. associate--r-N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \color{blue}{\left(\frac{2}{9} \cdot \frac{1}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)}\right)\right) \]
        7. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9} \cdot 1}{t} - \frac{\color{blue}{\frac{1}{27}}}{{t}^{2}}\right)\right)\right) \]
        8. metadata-evalN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)\right)\right) \]
        9. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{t \cdot \color{blue}{t}}\right)\right)\right) \]
        10. associate-/r*N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\frac{1}{27}}{t}}{\color{blue}{t}}\right)\right)\right) \]
        11. metadata-evalN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\frac{1}{27} \cdot 1}{t}}{t}\right)\right)\right) \]
        12. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right)\right) \]
        13. div-subN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{\color{blue}{t}}\right)\right) \]
        14. neg-sub0N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right)\right) \]
        15. mul-1-negN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(-1 \cdot \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}}\right)\right) \]
        16. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{-1 \cdot \left(\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}\right)}{\color{blue}{t}}\right)\right) \]
        17. /-lowering-/.f64N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(-1 \cdot \left(\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}\right)\right), \color{blue}{t}\right)\right) \]
      6. Simplified100.0%

        \[\leadsto \color{blue}{0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}} \]
    6. Recombined 3 regimes into one program.
    7. Final simplification99.7%

      \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq -0.33:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 + \frac{-0.037037037037037035 + \frac{-0.04938271604938271}{t}}{t}}{t}\\ \mathbf{elif}\;t \leq 0.23:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\ \end{array} \]
    8. Add Preprocessing

    Alternative 4: 99.2% accurate, 1.8× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\ \mathbf{if}\;t \leq -0.52:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.23:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
    (FPCore (t)
     :precision binary64
     (let* ((t_1
             (+
              0.8333333333333334
              (/ (+ -0.2222222222222222 (/ 0.037037037037037035 t)) t))))
       (if (<= t -0.52) t_1 (if (<= t 0.23) 0.5 t_1))))
    double code(double t) {
    	double t_1 = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
    	double tmp;
    	if (t <= -0.52) {
    		tmp = t_1;
    	} else if (t <= 0.23) {
    		tmp = 0.5;
    	} else {
    		tmp = t_1;
    	}
    	return tmp;
    }
    
    real(8) function code(t)
        real(8), intent (in) :: t
        real(8) :: t_1
        real(8) :: tmp
        t_1 = 0.8333333333333334d0 + (((-0.2222222222222222d0) + (0.037037037037037035d0 / t)) / t)
        if (t <= (-0.52d0)) then
            tmp = t_1
        else if (t <= 0.23d0) then
            tmp = 0.5d0
        else
            tmp = t_1
        end if
        code = tmp
    end function
    
    public static double code(double t) {
    	double t_1 = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
    	double tmp;
    	if (t <= -0.52) {
    		tmp = t_1;
    	} else if (t <= 0.23) {
    		tmp = 0.5;
    	} else {
    		tmp = t_1;
    	}
    	return tmp;
    }
    
    def code(t):
    	t_1 = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t)
    	tmp = 0
    	if t <= -0.52:
    		tmp = t_1
    	elif t <= 0.23:
    		tmp = 0.5
    	else:
    		tmp = t_1
    	return tmp
    
    function code(t)
    	t_1 = Float64(0.8333333333333334 + Float64(Float64(-0.2222222222222222 + Float64(0.037037037037037035 / t)) / t))
    	tmp = 0.0
    	if (t <= -0.52)
    		tmp = t_1;
    	elseif (t <= 0.23)
    		tmp = 0.5;
    	else
    		tmp = t_1;
    	end
    	return tmp
    end
    
    function tmp_2 = code(t)
    	t_1 = 0.8333333333333334 + ((-0.2222222222222222 + (0.037037037037037035 / t)) / t);
    	tmp = 0.0;
    	if (t <= -0.52)
    		tmp = t_1;
    	elseif (t <= 0.23)
    		tmp = 0.5;
    	else
    		tmp = t_1;
    	end
    	tmp_2 = tmp;
    end
    
    code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(N[(-0.2222222222222222 + N[(0.037037037037037035 / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.52], t$95$1, If[LessEqual[t, 0.23], 0.5, t$95$1]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_1 := 0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\
    \mathbf{if}\;t \leq -0.52:\\
    \;\;\;\;t\_1\\
    
    \mathbf{elif}\;t \leq 0.23:\\
    \;\;\;\;0.5\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_1\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if t < -0.52000000000000002 or 0.23000000000000001 < t

      1. Initial program 100.0%

        \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
      2. Simplified57.4%

        \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
      3. Add Preprocessing
      4. Taylor expanded in t around inf

        \[\leadsto \color{blue}{\left(\frac{5}{6} + \frac{\frac{1}{27}}{{t}^{2}}\right) - \frac{2}{9} \cdot \frac{1}{t}} \]
      5. Step-by-step derivation
        1. associate--l+N/A

          \[\leadsto \frac{5}{6} + \color{blue}{\left(\frac{\frac{1}{27}}{{t}^{2}} - \frac{2}{9} \cdot \frac{1}{t}\right)} \]
        2. sub-negN/A

          \[\leadsto \frac{5}{6} + \left(\frac{\frac{1}{27}}{{t}^{2}} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
        3. +-commutativeN/A

          \[\leadsto \frac{5}{6} + \left(\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right) + \color{blue}{\frac{\frac{1}{27}}{{t}^{2}}}\right) \]
        4. +-lowering-+.f64N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right) + \frac{\frac{1}{27}}{{t}^{2}}\right)}\right) \]
        5. neg-sub0N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\left(0 - \frac{2}{9} \cdot \frac{1}{t}\right) + \frac{\color{blue}{\frac{1}{27}}}{{t}^{2}}\right)\right) \]
        6. associate--r-N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \color{blue}{\left(\frac{2}{9} \cdot \frac{1}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)}\right)\right) \]
        7. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9} \cdot 1}{t} - \frac{\color{blue}{\frac{1}{27}}}{{t}^{2}}\right)\right)\right) \]
        8. metadata-evalN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)\right)\right) \]
        9. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{t \cdot \color{blue}{t}}\right)\right)\right) \]
        10. associate-/r*N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\frac{1}{27}}{t}}{\color{blue}{t}}\right)\right)\right) \]
        11. metadata-evalN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\frac{1}{27} \cdot 1}{t}}{t}\right)\right)\right) \]
        12. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right)\right) \]
        13. div-subN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(0 - \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{\color{blue}{t}}\right)\right) \]
        14. neg-sub0N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right)\right) \]
        15. mul-1-negN/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(-1 \cdot \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}}\right)\right) \]
        16. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{-1 \cdot \left(\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}\right)}{\color{blue}{t}}\right)\right) \]
        17. /-lowering-/.f64N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(-1 \cdot \left(\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}\right)\right), \color{blue}{t}\right)\right) \]
      6. Simplified99.2%

        \[\leadsto \color{blue}{0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}} \]

      if -0.52000000000000002 < t < 0.23000000000000001

      1. Initial program 100.0%

        \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
      2. Simplified100.0%

        \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
      3. Add Preprocessing
      4. Taylor expanded in t around 0

        \[\leadsto \color{blue}{\frac{1}{2}} \]
      5. Step-by-step derivation
        1. Simplified100.0%

          \[\leadsto \color{blue}{0.5} \]
      6. Recombined 2 regimes into one program.
      7. Final simplification99.6%

        \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq -0.52:\\ \;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\ \mathbf{elif}\;t \leq 0.23:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222 + \frac{0.037037037037037035}{t}}{t}\\ \end{array} \]
      8. Add Preprocessing

      Alternative 5: 99.1% accurate, 2.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.49:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.68:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
      (FPCore (t)
       :precision binary64
       (let* ((t_1 (+ 0.8333333333333334 (/ -0.2222222222222222 t))))
         (if (<= t -0.49) t_1 (if (<= t 0.68) 0.5 t_1))))
      double code(double t) {
      	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
      	double tmp;
      	if (t <= -0.49) {
      		tmp = t_1;
      	} else if (t <= 0.68) {
      		tmp = 0.5;
      	} else {
      		tmp = t_1;
      	}
      	return tmp;
      }
      
      real(8) function code(t)
          real(8), intent (in) :: t
          real(8) :: t_1
          real(8) :: tmp
          t_1 = 0.8333333333333334d0 + ((-0.2222222222222222d0) / t)
          if (t <= (-0.49d0)) then
              tmp = t_1
          else if (t <= 0.68d0) then
              tmp = 0.5d0
          else
              tmp = t_1
          end if
          code = tmp
      end function
      
      public static double code(double t) {
      	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
      	double tmp;
      	if (t <= -0.49) {
      		tmp = t_1;
      	} else if (t <= 0.68) {
      		tmp = 0.5;
      	} else {
      		tmp = t_1;
      	}
      	return tmp;
      }
      
      def code(t):
      	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t)
      	tmp = 0
      	if t <= -0.49:
      		tmp = t_1
      	elif t <= 0.68:
      		tmp = 0.5
      	else:
      		tmp = t_1
      	return tmp
      
      function code(t)
      	t_1 = Float64(0.8333333333333334 + Float64(-0.2222222222222222 / t))
      	tmp = 0.0
      	if (t <= -0.49)
      		tmp = t_1;
      	elseif (t <= 0.68)
      		tmp = 0.5;
      	else
      		tmp = t_1;
      	end
      	return tmp
      end
      
      function tmp_2 = code(t)
      	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
      	tmp = 0.0;
      	if (t <= -0.49)
      		tmp = t_1;
      	elseif (t <= 0.68)
      		tmp = 0.5;
      	else
      		tmp = t_1;
      	end
      	tmp_2 = tmp;
      end
      
      code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(-0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.49], t$95$1, If[LessEqual[t, 0.68], 0.5, t$95$1]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\
      \mathbf{if}\;t \leq -0.49:\\
      \;\;\;\;t\_1\\
      
      \mathbf{elif}\;t \leq 0.68:\\
      \;\;\;\;0.5\\
      
      \mathbf{else}:\\
      \;\;\;\;t\_1\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if t < -0.48999999999999999 or 0.680000000000000049 < t

        1. Initial program 100.0%

          \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
        2. Simplified57.4%

          \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
        3. Add Preprocessing
        4. Taylor expanded in t around inf

          \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
        5. Step-by-step derivation
          1. sub-negN/A

            \[\leadsto \frac{5}{6} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)} \]
          2. +-lowering-+.f64N/A

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
          3. associate-*r/N/A

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} \cdot 1}{t}\right)\right)\right) \]
          4. metadata-evalN/A

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9}}{t}\right)\right)\right) \]
          5. distribute-neg-fracN/A

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{\mathsf{neg}\left(\frac{2}{9}\right)}{\color{blue}{t}}\right)\right) \]
          6. /-lowering-/.f64N/A

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\mathsf{neg}\left(\frac{2}{9}\right)\right), \color{blue}{t}\right)\right) \]
          7. metadata-eval98.9%

            \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\frac{-2}{9}, t\right)\right) \]
        6. Simplified98.9%

          \[\leadsto \color{blue}{0.8333333333333334 + \frac{-0.2222222222222222}{t}} \]

        if -0.48999999999999999 < t < 0.680000000000000049

        1. Initial program 100.0%

          \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
        2. Simplified100.0%

          \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
        3. Add Preprocessing
        4. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2}} \]
        5. Step-by-step derivation
          1. Simplified100.0%

            \[\leadsto \color{blue}{0.5} \]
        6. Recombined 2 regimes into one program.
        7. Add Preprocessing

        Alternative 6: 98.6% accurate, 3.2× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -0.33:\\ \;\;\;\;0.8333333333333334\\ \mathbf{elif}\;t \leq 1:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \end{array} \]
        (FPCore (t)
         :precision binary64
         (if (<= t -0.33) 0.8333333333333334 (if (<= t 1.0) 0.5 0.8333333333333334)))
        double code(double t) {
        	double tmp;
        	if (t <= -0.33) {
        		tmp = 0.8333333333333334;
        	} else if (t <= 1.0) {
        		tmp = 0.5;
        	} else {
        		tmp = 0.8333333333333334;
        	}
        	return tmp;
        }
        
        real(8) function code(t)
            real(8), intent (in) :: t
            real(8) :: tmp
            if (t <= (-0.33d0)) then
                tmp = 0.8333333333333334d0
            else if (t <= 1.0d0) then
                tmp = 0.5d0
            else
                tmp = 0.8333333333333334d0
            end if
            code = tmp
        end function
        
        public static double code(double t) {
        	double tmp;
        	if (t <= -0.33) {
        		tmp = 0.8333333333333334;
        	} else if (t <= 1.0) {
        		tmp = 0.5;
        	} else {
        		tmp = 0.8333333333333334;
        	}
        	return tmp;
        }
        
        def code(t):
        	tmp = 0
        	if t <= -0.33:
        		tmp = 0.8333333333333334
        	elif t <= 1.0:
        		tmp = 0.5
        	else:
        		tmp = 0.8333333333333334
        	return tmp
        
        function code(t)
        	tmp = 0.0
        	if (t <= -0.33)
        		tmp = 0.8333333333333334;
        	elseif (t <= 1.0)
        		tmp = 0.5;
        	else
        		tmp = 0.8333333333333334;
        	end
        	return tmp
        end
        
        function tmp_2 = code(t)
        	tmp = 0.0;
        	if (t <= -0.33)
        		tmp = 0.8333333333333334;
        	elseif (t <= 1.0)
        		tmp = 0.5;
        	else
        		tmp = 0.8333333333333334;
        	end
        	tmp_2 = tmp;
        end
        
        code[t_] := If[LessEqual[t, -0.33], 0.8333333333333334, If[LessEqual[t, 1.0], 0.5, 0.8333333333333334]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        \mathbf{if}\;t \leq -0.33:\\
        \;\;\;\;0.8333333333333334\\
        
        \mathbf{elif}\;t \leq 1:\\
        \;\;\;\;0.5\\
        
        \mathbf{else}:\\
        \;\;\;\;0.8333333333333334\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if t < -0.330000000000000016 or 1 < t

          1. Initial program 100.0%

            \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
          2. Simplified57.4%

            \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
          3. Add Preprocessing
          4. Taylor expanded in t around inf

            \[\leadsto \color{blue}{\frac{5}{6}} \]
          5. Step-by-step derivation
            1. Simplified97.6%

              \[\leadsto \color{blue}{0.8333333333333334} \]

            if -0.330000000000000016 < t < 1

            1. Initial program 100.0%

              \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
            2. Simplified100.0%

              \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
            3. Add Preprocessing
            4. Taylor expanded in t around 0

              \[\leadsto \color{blue}{\frac{1}{2}} \]
            5. Step-by-step derivation
              1. Simplified100.0%

                \[\leadsto \color{blue}{0.5} \]
            6. Recombined 2 regimes into one program.
            7. Add Preprocessing

            Alternative 7: 59.0% accurate, 35.0× speedup?

            \[\begin{array}{l} \\ 0.5 \end{array} \]
            (FPCore (t) :precision binary64 0.5)
            double code(double t) {
            	return 0.5;
            }
            
            real(8) function code(t)
                real(8), intent (in) :: t
                code = 0.5d0
            end function
            
            public static double code(double t) {
            	return 0.5;
            }
            
            def code(t):
            	return 0.5
            
            function code(t)
            	return 0.5
            end
            
            function tmp = code(t)
            	tmp = 0.5;
            end
            
            code[t_] := 0.5
            
            \begin{array}{l}
            
            \\
            0.5
            \end{array}
            
            Derivation
            1. Initial program 100.0%

              \[\frac{1 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}}{2 + \frac{2 \cdot t}{1 + t} \cdot \frac{2 \cdot t}{1 + t}} \]
            2. Simplified76.5%

              \[\leadsto \color{blue}{0.5 + \frac{\frac{\frac{t \cdot t}{1 + t}}{1 + t}}{1 + \frac{\frac{2 \cdot \left(t \cdot t\right)}{1 + t}}{1 + t}}} \]
            3. Add Preprocessing
            4. Taylor expanded in t around 0

              \[\leadsto \color{blue}{\frac{1}{2}} \]
            5. Step-by-step derivation
              1. Simplified55.8%

                \[\leadsto \color{blue}{0.5} \]
              2. Add Preprocessing

              Reproduce

              ?
              herbie shell --seed 2024160 
              (FPCore (t)
                :name "Kahan p13 Example 1"
                :precision binary64
                (/ (+ 1.0 (* (/ (* 2.0 t) (+ 1.0 t)) (/ (* 2.0 t) (+ 1.0 t)))) (+ 2.0 (* (/ (* 2.0 t) (+ 1.0 t)) (/ (* 2.0 t) (+ 1.0 t))))))