Octave 3.8, jcobi/4, as called

Percentage Accurate: 28.3% → 99.4%
Time: 5.0s
Alternatives: 5
Speedup: 25.0×

Specification

?
\[i > 0\]
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(2 \cdot i\right) \cdot \left(2 \cdot i\right)\\ \frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{t_0}}{t_0 - 1} \end{array} \end{array} \]
(FPCore (i)
 :precision binary64
 (let* ((t_0 (* (* 2.0 i) (* 2.0 i))))
   (/ (/ (* (* i i) (* i i)) t_0) (- t_0 1.0))))
double code(double i) {
	double t_0 = (2.0 * i) * (2.0 * i);
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
}
real(8) function code(i)
    real(8), intent (in) :: i
    real(8) :: t_0
    t_0 = (2.0d0 * i) * (2.0d0 * i)
    code = (((i * i) * (i * i)) / t_0) / (t_0 - 1.0d0)
end function
public static double code(double i) {
	double t_0 = (2.0 * i) * (2.0 * i);
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
}
def code(i):
	t_0 = (2.0 * i) * (2.0 * i)
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0)
function code(i)
	t_0 = Float64(Float64(2.0 * i) * Float64(2.0 * i))
	return Float64(Float64(Float64(Float64(i * i) * Float64(i * i)) / t_0) / Float64(t_0 - 1.0))
end
function tmp = code(i)
	t_0 = (2.0 * i) * (2.0 * i);
	tmp = (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
end
code[i_] := Block[{t$95$0 = N[(N[(2.0 * i), $MachinePrecision] * N[(2.0 * i), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(i * i), $MachinePrecision] * N[(i * i), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] / N[(t$95$0 - 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(2 \cdot i\right) \cdot \left(2 \cdot i\right)\\
\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{t_0}}{t_0 - 1}
\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 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: 28.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(2 \cdot i\right) \cdot \left(2 \cdot i\right)\\ \frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{t_0}}{t_0 - 1} \end{array} \end{array} \]
(FPCore (i)
 :precision binary64
 (let* ((t_0 (* (* 2.0 i) (* 2.0 i))))
   (/ (/ (* (* i i) (* i i)) t_0) (- t_0 1.0))))
double code(double i) {
	double t_0 = (2.0 * i) * (2.0 * i);
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
}
real(8) function code(i)
    real(8), intent (in) :: i
    real(8) :: t_0
    t_0 = (2.0d0 * i) * (2.0d0 * i)
    code = (((i * i) * (i * i)) / t_0) / (t_0 - 1.0d0)
end function
public static double code(double i) {
	double t_0 = (2.0 * i) * (2.0 * i);
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
}
def code(i):
	t_0 = (2.0 * i) * (2.0 * i)
	return (((i * i) * (i * i)) / t_0) / (t_0 - 1.0)
function code(i)
	t_0 = Float64(Float64(2.0 * i) * Float64(2.0 * i))
	return Float64(Float64(Float64(Float64(i * i) * Float64(i * i)) / t_0) / Float64(t_0 - 1.0))
end
function tmp = code(i)
	t_0 = (2.0 * i) * (2.0 * i);
	tmp = (((i * i) * (i * i)) / t_0) / (t_0 - 1.0);
end
code[i_] := Block[{t$95$0 = N[(N[(2.0 * i), $MachinePrecision] * N[(2.0 * i), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(i * i), $MachinePrecision] * N[(i * i), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] / N[(t$95$0 - 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(2 \cdot i\right) \cdot \left(2 \cdot i\right)\\
\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{t_0}}{t_0 - 1}
\end{array}
\end{array}

Alternative 1: 99.4% accurate, 2.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\ \end{array} \end{array} \]
(FPCore (i)
 :precision binary64
 (if (<= i 0.5) (* (* i i) (- -0.25 (* i i))) (+ 0.0625 (/ 0.015625 (* i i)))))
double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = (i * i) * (-0.25 - (i * i));
	} else {
		tmp = 0.0625 + (0.015625 / (i * i));
	}
	return tmp;
}
real(8) function code(i)
    real(8), intent (in) :: i
    real(8) :: tmp
    if (i <= 0.5d0) then
        tmp = (i * i) * ((-0.25d0) - (i * i))
    else
        tmp = 0.0625d0 + (0.015625d0 / (i * i))
    end if
    code = tmp
end function
public static double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = (i * i) * (-0.25 - (i * i));
	} else {
		tmp = 0.0625 + (0.015625 / (i * i));
	}
	return tmp;
}
def code(i):
	tmp = 0
	if i <= 0.5:
		tmp = (i * i) * (-0.25 - (i * i))
	else:
		tmp = 0.0625 + (0.015625 / (i * i))
	return tmp
function code(i)
	tmp = 0.0
	if (i <= 0.5)
		tmp = Float64(Float64(i * i) * Float64(-0.25 - Float64(i * i)));
	else
		tmp = Float64(0.0625 + Float64(0.015625 / Float64(i * i)));
	end
	return tmp
end
function tmp_2 = code(i)
	tmp = 0.0;
	if (i <= 0.5)
		tmp = (i * i) * (-0.25 - (i * i));
	else
		tmp = 0.0625 + (0.015625 / (i * i));
	end
	tmp_2 = tmp;
end
code[i_] := If[LessEqual[i, 0.5], N[(N[(i * i), $MachinePrecision] * N[(-0.25 - N[(i * i), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(0.0625 + N[(0.015625 / N[(i * i), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;i \leq 0.5:\\
\;\;\;\;\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)\\

\mathbf{else}:\\
\;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if i < 0.5

    1. Initial program 25.6%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac99.9%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*99.8%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*99.8%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/99.8%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*98.9%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*99.0%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified87.1%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Step-by-step derivation
      1. metadata-eval87.1%

        \[\leadsto \frac{\color{blue}{\frac{1}{4}}}{4 - \frac{i}{{i}^{3}}} \]
      2. *-inverses39.0%

        \[\leadsto \frac{\frac{\color{blue}{\frac{i \cdot i}{i \cdot i}}}{4}}{4 - \frac{i}{{i}^{3}}} \]
      3. associate-/r*39.0%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{\left(i \cdot i\right) \cdot 4}}}{4 - \frac{i}{{i}^{3}}} \]
      4. *-commutative39.0%

        \[\leadsto \frac{\frac{i \cdot i}{\color{blue}{4 \cdot \left(i \cdot i\right)}}}{4 - \frac{i}{{i}^{3}}} \]
      5. flip--22.0%

        \[\leadsto \frac{\frac{i \cdot i}{4 \cdot \left(i \cdot i\right)}}{\color{blue}{\frac{4 \cdot 4 - \frac{i}{{i}^{3}} \cdot \frac{i}{{i}^{3}}}{4 + \frac{i}{{i}^{3}}}}} \]
      6. associate-/r/21.9%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{4 \cdot \left(i \cdot i\right)}}{4 \cdot 4 - \frac{i}{{i}^{3}} \cdot \frac{i}{{i}^{3}}} \cdot \left(4 + \frac{i}{{i}^{3}}\right)} \]
    5. Applied egg-rr22.8%

      \[\leadsto \color{blue}{\frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left({i}^{-2} + 4\right)} \]
    6. Step-by-step derivation
      1. metadata-eval22.8%

        \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left({i}^{\color{blue}{\left(2 \cdot -1\right)}} + 4\right) \]
      2. pow-sqr22.7%

        \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left(\color{blue}{{i}^{-1} \cdot {i}^{-1}} + 4\right) \]
      3. pow-prod-down22.7%

        \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left(\color{blue}{{\left(i \cdot i\right)}^{-1}} + 4\right) \]
      4. inv-pow22.7%

        \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left(\color{blue}{\frac{1}{i \cdot i}} + 4\right) \]
      5. associate-/r*22.8%

        \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left(\color{blue}{\frac{\frac{1}{i}}{i}} + 4\right) \]
    7. Applied egg-rr22.8%

      \[\leadsto \frac{0.25}{16 - \frac{1}{{i}^{4}}} \cdot \left(\color{blue}{\frac{\frac{1}{i}}{i}} + 4\right) \]
    8. Taylor expanded in i around 0 24.0%

      \[\leadsto \color{blue}{\left(-0.25 \cdot {i}^{4}\right)} \cdot \left(\frac{\frac{1}{i}}{i} + 4\right) \]
    9. Taylor expanded in i around 0 100.0%

      \[\leadsto \color{blue}{-1 \cdot {i}^{4} + -0.25 \cdot {i}^{2}} \]
    10. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto \color{blue}{-0.25 \cdot {i}^{2} + -1 \cdot {i}^{4}} \]
      2. unpow2100.0%

        \[\leadsto -0.25 \cdot \color{blue}{\left(i \cdot i\right)} + -1 \cdot {i}^{4} \]
      3. mul-1-neg100.0%

        \[\leadsto -0.25 \cdot \left(i \cdot i\right) + \color{blue}{\left(-{i}^{4}\right)} \]
      4. unsub-neg100.0%

        \[\leadsto \color{blue}{-0.25 \cdot \left(i \cdot i\right) - {i}^{4}} \]
      5. metadata-eval100.0%

        \[\leadsto -0.25 \cdot \left(i \cdot i\right) - {i}^{\color{blue}{\left(2 \cdot 2\right)}} \]
      6. pow-sqr100.0%

        \[\leadsto -0.25 \cdot \left(i \cdot i\right) - \color{blue}{{i}^{2} \cdot {i}^{2}} \]
      7. unpow2100.0%

        \[\leadsto -0.25 \cdot \left(i \cdot i\right) - \color{blue}{\left(i \cdot i\right)} \cdot {i}^{2} \]
      8. unpow2100.0%

        \[\leadsto -0.25 \cdot \left(i \cdot i\right) - \left(i \cdot i\right) \cdot \color{blue}{\left(i \cdot i\right)} \]
      9. distribute-rgt-out--100.0%

        \[\leadsto \color{blue}{\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)} \]
    11. Simplified100.0%

      \[\leadsto \color{blue}{\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)} \]

    if 0.5 < i

    1. Initial program 20.9%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac46.4%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*46.4%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*46.5%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/46.5%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*46.5%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*46.5%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Taylor expanded in i around inf 99.9%

      \[\leadsto \color{blue}{0.0625 + 0.015625 \cdot \frac{1}{{i}^{2}}} \]
    5. Step-by-step derivation
      1. unpow299.9%

        \[\leadsto 0.0625 + 0.015625 \cdot \frac{1}{\color{blue}{i \cdot i}} \]
      2. associate-*r/99.9%

        \[\leadsto 0.0625 + \color{blue}{\frac{0.015625 \cdot 1}{i \cdot i}} \]
      3. metadata-eval99.9%

        \[\leadsto 0.0625 + \frac{\color{blue}{0.015625}}{i \cdot i} \]
    6. Simplified99.9%

      \[\leadsto \color{blue}{0.0625 + \frac{0.015625}{i \cdot i}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\ \end{array} \]

Alternative 2: 99.1% accurate, 2.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;i \cdot \left(i \cdot -0.25\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\ \end{array} \end{array} \]
(FPCore (i)
 :precision binary64
 (if (<= i 0.5) (* i (* i -0.25)) (+ 0.0625 (/ 0.015625 (* i i)))))
double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = i * (i * -0.25);
	} else {
		tmp = 0.0625 + (0.015625 / (i * i));
	}
	return tmp;
}
real(8) function code(i)
    real(8), intent (in) :: i
    real(8) :: tmp
    if (i <= 0.5d0) then
        tmp = i * (i * (-0.25d0))
    else
        tmp = 0.0625d0 + (0.015625d0 / (i * i))
    end if
    code = tmp
end function
public static double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = i * (i * -0.25);
	} else {
		tmp = 0.0625 + (0.015625 / (i * i));
	}
	return tmp;
}
def code(i):
	tmp = 0
	if i <= 0.5:
		tmp = i * (i * -0.25)
	else:
		tmp = 0.0625 + (0.015625 / (i * i))
	return tmp
function code(i)
	tmp = 0.0
	if (i <= 0.5)
		tmp = Float64(i * Float64(i * -0.25));
	else
		tmp = Float64(0.0625 + Float64(0.015625 / Float64(i * i)));
	end
	return tmp
end
function tmp_2 = code(i)
	tmp = 0.0;
	if (i <= 0.5)
		tmp = i * (i * -0.25);
	else
		tmp = 0.0625 + (0.015625 / (i * i));
	end
	tmp_2 = tmp;
end
code[i_] := If[LessEqual[i, 0.5], N[(i * N[(i * -0.25), $MachinePrecision]), $MachinePrecision], N[(0.0625 + N[(0.015625 / N[(i * i), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;i \leq 0.5:\\
\;\;\;\;i \cdot \left(i \cdot -0.25\right)\\

\mathbf{else}:\\
\;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if i < 0.5

    1. Initial program 25.6%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac99.9%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*99.8%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*99.8%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/99.8%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*98.9%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*99.0%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified87.1%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Taylor expanded in i around 0 99.7%

      \[\leadsto \color{blue}{-0.25 \cdot {i}^{2}} \]
    5. Step-by-step derivation
      1. unpow299.7%

        \[\leadsto -0.25 \cdot \color{blue}{\left(i \cdot i\right)} \]
      2. *-commutative99.7%

        \[\leadsto \color{blue}{\left(i \cdot i\right) \cdot -0.25} \]
      3. associate-*l*99.7%

        \[\leadsto \color{blue}{i \cdot \left(i \cdot -0.25\right)} \]
    6. Simplified99.7%

      \[\leadsto \color{blue}{i \cdot \left(i \cdot -0.25\right)} \]

    if 0.5 < i

    1. Initial program 20.9%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac46.4%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*46.4%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*46.5%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/46.5%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*46.5%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*46.5%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Taylor expanded in i around inf 99.9%

      \[\leadsto \color{blue}{0.0625 + 0.015625 \cdot \frac{1}{{i}^{2}}} \]
    5. Step-by-step derivation
      1. unpow299.9%

        \[\leadsto 0.0625 + 0.015625 \cdot \frac{1}{\color{blue}{i \cdot i}} \]
      2. associate-*r/99.9%

        \[\leadsto 0.0625 + \color{blue}{\frac{0.015625 \cdot 1}{i \cdot i}} \]
      3. metadata-eval99.9%

        \[\leadsto 0.0625 + \frac{\color{blue}{0.015625}}{i \cdot i} \]
    6. Simplified99.9%

      \[\leadsto \color{blue}{0.0625 + \frac{0.015625}{i \cdot i}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;i \cdot \left(i \cdot -0.25\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625 + \frac{0.015625}{i \cdot i}\\ \end{array} \]

Alternative 3: 99.5% accurate, 2.8× speedup?

\[\begin{array}{l} \\ \frac{0.25}{4 - \frac{1}{i \cdot i}} \end{array} \]
(FPCore (i) :precision binary64 (/ 0.25 (- 4.0 (/ 1.0 (* i i)))))
double code(double i) {
	return 0.25 / (4.0 - (1.0 / (i * i)));
}
real(8) function code(i)
    real(8), intent (in) :: i
    code = 0.25d0 / (4.0d0 - (1.0d0 / (i * i)))
end function
public static double code(double i) {
	return 0.25 / (4.0 - (1.0 / (i * i)));
}
def code(i):
	return 0.25 / (4.0 - (1.0 / (i * i)))
function code(i)
	return Float64(0.25 / Float64(4.0 - Float64(1.0 / Float64(i * i))))
end
function tmp = code(i)
	tmp = 0.25 / (4.0 - (1.0 / (i * i)));
end
code[i_] := N[(0.25 / N[(4.0 - N[(1.0 / N[(i * i), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{0.25}{4 - \frac{1}{i \cdot i}}
\end{array}
Derivation
  1. Initial program 23.3%

    \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
  2. Step-by-step derivation
    1. times-frac73.0%

      \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. associate-/l*72.9%

      \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
    3. associate-/l*72.9%

      \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
    4. associate-/l/72.9%

      \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
    5. associate-/r/72.5%

      \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
    6. associate-/l*72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
    7. *-inverses72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
    8. metadata-eval72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
    9. associate-*l*72.5%

      \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
    10. *-commutative72.5%

      \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    11. associate-/r*72.6%

      \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
  3. Simplified93.6%

    \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
  4. Taylor expanded in i around 0 99.5%

    \[\leadsto \frac{0.25}{4 - \color{blue}{\frac{1}{{i}^{2}}}} \]
  5. Step-by-step derivation
    1. unpow299.5%

      \[\leadsto \frac{0.25}{4 - \frac{1}{\color{blue}{i \cdot i}}} \]
  6. Simplified99.5%

    \[\leadsto \frac{0.25}{4 - \color{blue}{\frac{1}{i \cdot i}}} \]
  7. Final simplification99.5%

    \[\leadsto \frac{0.25}{4 - \frac{1}{i \cdot i}} \]

Alternative 4: 98.8% accurate, 3.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;i \cdot \left(i \cdot -0.25\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625\\ \end{array} \end{array} \]
(FPCore (i) :precision binary64 (if (<= i 0.5) (* i (* i -0.25)) 0.0625))
double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = i * (i * -0.25);
	} else {
		tmp = 0.0625;
	}
	return tmp;
}
real(8) function code(i)
    real(8), intent (in) :: i
    real(8) :: tmp
    if (i <= 0.5d0) then
        tmp = i * (i * (-0.25d0))
    else
        tmp = 0.0625d0
    end if
    code = tmp
end function
public static double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = i * (i * -0.25);
	} else {
		tmp = 0.0625;
	}
	return tmp;
}
def code(i):
	tmp = 0
	if i <= 0.5:
		tmp = i * (i * -0.25)
	else:
		tmp = 0.0625
	return tmp
function code(i)
	tmp = 0.0
	if (i <= 0.5)
		tmp = Float64(i * Float64(i * -0.25));
	else
		tmp = 0.0625;
	end
	return tmp
end
function tmp_2 = code(i)
	tmp = 0.0;
	if (i <= 0.5)
		tmp = i * (i * -0.25);
	else
		tmp = 0.0625;
	end
	tmp_2 = tmp;
end
code[i_] := If[LessEqual[i, 0.5], N[(i * N[(i * -0.25), $MachinePrecision]), $MachinePrecision], 0.0625]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;i \leq 0.5:\\
\;\;\;\;i \cdot \left(i \cdot -0.25\right)\\

\mathbf{else}:\\
\;\;\;\;0.0625\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if i < 0.5

    1. Initial program 25.6%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac99.9%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*99.8%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*99.8%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/99.8%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval98.9%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*98.9%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative98.9%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*99.0%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified87.1%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Taylor expanded in i around 0 99.7%

      \[\leadsto \color{blue}{-0.25 \cdot {i}^{2}} \]
    5. Step-by-step derivation
      1. unpow299.7%

        \[\leadsto -0.25 \cdot \color{blue}{\left(i \cdot i\right)} \]
      2. *-commutative99.7%

        \[\leadsto \color{blue}{\left(i \cdot i\right) \cdot -0.25} \]
      3. associate-*l*99.7%

        \[\leadsto \color{blue}{i \cdot \left(i \cdot -0.25\right)} \]
    6. Simplified99.7%

      \[\leadsto \color{blue}{i \cdot \left(i \cdot -0.25\right)} \]

    if 0.5 < i

    1. Initial program 20.9%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. times-frac46.4%

        \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. associate-/l*46.4%

        \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
      3. associate-/l*46.5%

        \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
      4. associate-/l/46.5%

        \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
      5. associate-/r/46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
      6. associate-/l*46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
      7. *-inverses46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
      8. metadata-eval46.5%

        \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
      9. associate-*l*46.5%

        \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      10. *-commutative46.5%

        \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
      11. associate-/r*46.5%

        \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
    4. Taylor expanded in i around inf 99.6%

      \[\leadsto \color{blue}{0.0625} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;i \cdot \left(i \cdot -0.25\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625\\ \end{array} \]

Alternative 5: 52.0% accurate, 25.0× speedup?

\[\begin{array}{l} \\ 0.0625 \end{array} \]
(FPCore (i) :precision binary64 0.0625)
double code(double i) {
	return 0.0625;
}
real(8) function code(i)
    real(8), intent (in) :: i
    code = 0.0625d0
end function
public static double code(double i) {
	return 0.0625;
}
def code(i):
	return 0.0625
function code(i)
	return 0.0625
end
function tmp = code(i)
	tmp = 0.0625;
end
code[i_] := 0.0625
\begin{array}{l}

\\
0.0625
\end{array}
Derivation
  1. Initial program 23.3%

    \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
  2. Step-by-step derivation
    1. times-frac73.0%

      \[\leadsto \frac{\color{blue}{\frac{i \cdot i}{2 \cdot i} \cdot \frac{i \cdot i}{2 \cdot i}}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. associate-/l*72.9%

      \[\leadsto \color{blue}{\frac{\frac{i \cdot i}{2 \cdot i}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}}} \]
    3. associate-/l*72.9%

      \[\leadsto \frac{\color{blue}{\frac{i}{\frac{2 \cdot i}{i}}}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}}} \]
    4. associate-/l/72.9%

      \[\leadsto \color{blue}{\frac{i}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{\frac{i \cdot i}{2 \cdot i}} \cdot \frac{2 \cdot i}{i}}} \]
    5. associate-/r/72.5%

      \[\leadsto \frac{i}{\color{blue}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right)} \cdot \frac{2 \cdot i}{i}} \]
    6. associate-/l*72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{\frac{2}{\frac{i}{i}}}} \]
    7. *-inverses72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \frac{2}{\color{blue}{1}}} \]
    8. metadata-eval72.5%

      \[\leadsto \frac{i}{\left(\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(2 \cdot i\right)\right) \cdot \color{blue}{2}} \]
    9. associate-*l*72.5%

      \[\leadsto \frac{i}{\color{blue}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i} \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
    10. *-commutative72.5%

      \[\leadsto \frac{i}{\color{blue}{\left(\left(2 \cdot i\right) \cdot 2\right) \cdot \frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
    11. associate-/r*72.6%

      \[\leadsto \color{blue}{\frac{\frac{i}{\left(2 \cdot i\right) \cdot 2}}{\frac{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1}{i \cdot i}}} \]
  3. Simplified93.6%

    \[\leadsto \color{blue}{\frac{0.25}{4 - \frac{i}{{i}^{3}}}} \]
  4. Taylor expanded in i around inf 51.5%

    \[\leadsto \color{blue}{0.0625} \]
  5. Final simplification51.5%

    \[\leadsto 0.0625 \]

Reproduce

?
herbie shell --seed 2023217 
(FPCore (i)
  :name "Octave 3.8, jcobi/4, as called"
  :precision binary64
  :pre (> i 0.0)
  (/ (/ (* (* i i) (* i i)) (* (* 2.0 i) (* 2.0 i))) (- (* (* 2.0 i) (* 2.0 i)) 1.0)))