Octave 3.8, jcobi/4, as called

Percentage Accurate: 27.2% → 99.8%
Time: 6.8s
Alternatives: 4
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 4 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: 27.2% 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: 99.8% accurate, 2.8× speedup?

\[\begin{array}{l} \\ \frac{i}{\frac{-4}{i} - i \cdot -16} \end{array} \]
(FPCore (i) :precision binary64 (/ i (- (/ -4.0 i) (* i -16.0))))
double code(double i) {
	return i / ((-4.0 / i) - (i * -16.0));
}
real(8) function code(i)
    real(8), intent (in) :: i
    code = i / (((-4.0d0) / i) - (i * (-16.0d0)))
end function
public static double code(double i) {
	return i / ((-4.0 / i) - (i * -16.0));
}
def code(i):
	return i / ((-4.0 / i) - (i * -16.0))
function code(i)
	return Float64(i / Float64(Float64(-4.0 / i) - Float64(i * -16.0)))
end
function tmp = code(i)
	tmp = i / ((-4.0 / i) - (i * -16.0));
end
code[i_] := N[(i / N[(N[(-4.0 / i), $MachinePrecision] - N[(i * -16.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{i}{\frac{-4}{i} - i \cdot -16}
\end{array}
Derivation
  1. Initial program 26.9%

    \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
  2. Step-by-step derivation
    1. associate-/l/N/A

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

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

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

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

      \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
    6. times-fracN/A

      \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
    7. *-inversesN/A

      \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
    8. *-rgt-identityN/A

      \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
    9. associate-/l/N/A

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

      \[\leadsto \frac{\frac{\left(i \cdot i\right) \cdot i}{\left(2 \cdot i\right) \cdot 2}}{\color{blue}{\left(2 \cdot i\right)} \cdot \left(2 \cdot i\right) - 1} \]
  3. Simplified75.4%

    \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. associate-*l/N/A

      \[\leadsto \frac{i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4} \cdot \color{blue}{i} \]
    2. associate-/r/N/A

      \[\leadsto \frac{i}{\color{blue}{\frac{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}{i}}} \]
    3. /-lowering-/.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \color{blue}{\left(\frac{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}{i}\right)}\right) \]
    4. /-lowering-/.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\left(\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4\right), \color{blue}{i}\right)\right) \]
    5. +-commutativeN/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\left(-4 + \left(\left(i \cdot i\right) \cdot 4\right) \cdot 4\right), i\right)\right) \]
    6. cancel-sign-subN/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\left(-4 - \left(\mathsf{neg}\left(\left(i \cdot i\right) \cdot 4\right)\right) \cdot 4\right), i\right)\right) \]
    7. distribute-lft-neg-inN/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\left(-4 - \left(\mathsf{neg}\left(\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4\right)\right)\right), i\right)\right) \]
    8. --lowering--.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \left(\mathsf{neg}\left(\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4\right)\right)\right), i\right)\right) \]
    9. associate-*l*N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \left(\mathsf{neg}\left(\left(i \cdot i\right) \cdot \left(4 \cdot 4\right)\right)\right)\right), i\right)\right) \]
    10. distribute-rgt-neg-inN/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \left(\left(i \cdot i\right) \cdot \left(\mathsf{neg}\left(4 \cdot 4\right)\right)\right)\right), i\right)\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \mathsf{*.f64}\left(\left(i \cdot i\right), \left(\mathsf{neg}\left(4 \cdot 4\right)\right)\right)\right), i\right)\right) \]
    12. *-lowering-*.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\mathsf{neg}\left(4 \cdot 4\right)\right)\right)\right), i\right)\right) \]
    13. metadata-evalN/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\mathsf{neg}\left(16\right)\right)\right)\right), i\right)\right) \]
    14. metadata-eval76.0%

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(-4, \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), -16\right)\right), i\right)\right) \]
  6. Applied egg-rr76.0%

    \[\leadsto \color{blue}{\frac{i}{\frac{-4 - \left(i \cdot i\right) \cdot -16}{i}}} \]
  7. Step-by-step derivation
    1. div-subN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - \color{blue}{\frac{\left(i \cdot i\right) \cdot -16}{i}}\right)\right) \]
    2. div-invN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - \left(\left(i \cdot i\right) \cdot -16\right) \cdot \color{blue}{\frac{1}{i}}\right)\right) \]
    3. *-commutativeN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - \left(-16 \cdot \left(i \cdot i\right)\right) \cdot \frac{\color{blue}{1}}{i}\right)\right) \]
    4. associate-*l*N/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot \color{blue}{\left(\left(i \cdot i\right) \cdot \frac{1}{i}\right)}\right)\right) \]
    5. pow2N/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot \left({i}^{2} \cdot \frac{\color{blue}{1}}{i}\right)\right)\right) \]
    6. inv-powN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot \left({i}^{2} \cdot {i}^{\color{blue}{-1}}\right)\right)\right) \]
    7. pow-prod-upN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot {i}^{\color{blue}{\left(2 + -1\right)}}\right)\right) \]
    8. metadata-evalN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot {i}^{1}\right)\right) \]
    9. unpow1N/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - -16 \cdot i\right)\right) \]
    10. *-commutativeN/A

      \[\leadsto \mathsf{/.f64}\left(i, \left(\frac{-4}{i} - i \cdot \color{blue}{-16}\right)\right) \]
    11. --lowering--.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{\_.f64}\left(\left(\frac{-4}{i}\right), \color{blue}{\left(i \cdot -16\right)}\right)\right) \]
    12. /-lowering-/.f64N/A

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{\_.f64}\left(\mathsf{/.f64}\left(-4, i\right), \left(\color{blue}{i} \cdot -16\right)\right)\right) \]
    13. *-lowering-*.f6499.9%

      \[\leadsto \mathsf{/.f64}\left(i, \mathsf{\_.f64}\left(\mathsf{/.f64}\left(-4, i\right), \mathsf{*.f64}\left(i, \color{blue}{-16}\right)\right)\right) \]
  8. Applied egg-rr99.9%

    \[\leadsto \frac{i}{\color{blue}{\frac{-4}{i} - i \cdot -16}} \]
  9. Add Preprocessing

Alternative 2: 99.1% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;i \leq 0.5:\\ \;\;\;\;\left(i \cdot i\right) \cdot \left(-0.25 - i \cdot i\right)\\ \mathbf{else}:\\ \;\;\;\;0.0625\\ \end{array} \end{array} \]
(FPCore (i)
 :precision binary64
 (if (<= i 0.5) (* (* i i) (- -0.25 (* i i))) 0.0625))
double code(double i) {
	double tmp;
	if (i <= 0.5) {
		tmp = (i * i) * (-0.25 - (i * i));
	} 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) - (i * i))
    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 - (i * i));
	} else {
		tmp = 0.0625;
	}
	return tmp;
}
def code(i):
	tmp = 0
	if i <= 0.5:
		tmp = (i * i) * (-0.25 - (i * i))
	else:
		tmp = 0.0625
	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 = 0.0625;
	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;
	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], 0.0625]
\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\\


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

    1. Initial program 32.5%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. associate-/l/N/A

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

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

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

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

        \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
      6. times-fracN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
      7. *-inversesN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
      8. *-rgt-identityN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      9. associate-/l/N/A

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

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

      \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
    4. Add Preprocessing
    5. Taylor expanded in i around 0

      \[\leadsto \color{blue}{{i}^{2} \cdot \left(-1 \cdot {i}^{2} - \frac{1}{4}\right)} \]
    6. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(\left({i}^{2}\right), \color{blue}{\left(-1 \cdot {i}^{2} - \frac{1}{4}\right)}\right) \]
      2. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(\left(i \cdot i\right), \left(\color{blue}{-1 \cdot {i}^{2}} - \frac{1}{4}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\color{blue}{-1 \cdot {i}^{2}} - \frac{1}{4}\right)\right) \]
      4. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(-1 \cdot {i}^{2} + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{4}\right)\right)}\right)\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(-1 \cdot {i}^{2} + \frac{-1}{4}\right)\right) \]
      6. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\frac{-1}{4} + \color{blue}{-1 \cdot {i}^{2}}\right)\right) \]
      7. mul-1-negN/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\frac{-1}{4} + \left(\mathsf{neg}\left({i}^{2}\right)\right)\right)\right) \]
      8. unsub-negN/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \left(\frac{-1}{4} - \color{blue}{{i}^{2}}\right)\right) \]
      9. --lowering--.f64N/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \mathsf{\_.f64}\left(\frac{-1}{4}, \color{blue}{\left({i}^{2}\right)}\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \mathsf{\_.f64}\left(\frac{-1}{4}, \left(i \cdot \color{blue}{i}\right)\right)\right) \]
      11. *-lowering-*.f6499.3%

        \[\leadsto \mathsf{*.f64}\left(\mathsf{*.f64}\left(i, i\right), \mathsf{\_.f64}\left(\frac{-1}{4}, \mathsf{*.f64}\left(i, \color{blue}{i}\right)\right)\right) \]
    7. Simplified99.3%

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

    if 0.5 < i

    1. Initial program 20.3%

      \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
    2. Step-by-step derivation
      1. associate-/l/N/A

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

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

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

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

        \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
      6. times-fracN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
      7. *-inversesN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
      8. *-rgt-identityN/A

        \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
      9. associate-/l/N/A

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

        \[\leadsto \frac{\frac{\left(i \cdot i\right) \cdot i}{\left(2 \cdot i\right) \cdot 2}}{\color{blue}{\left(2 \cdot i\right)} \cdot \left(2 \cdot i\right) - 1} \]
    3. Simplified46.6%

      \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
    4. Add Preprocessing
    5. Taylor expanded in i around inf

      \[\leadsto \color{blue}{\frac{1}{16}} \]
    6. Step-by-step derivation
      1. Simplified100.0%

        \[\leadsto \color{blue}{0.0625} \]
    7. Recombined 2 regimes into one program.
    8. Add Preprocessing

    Alternative 3: 98.9% accurate, 2.5× 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 32.5%

        \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. Step-by-step derivation
        1. associate-/l/N/A

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

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

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

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

          \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
        6. times-fracN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
        7. *-inversesN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
        8. *-rgt-identityN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
        9. associate-/l/N/A

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

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

        \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
      4. Add Preprocessing
      5. Taylor expanded in i around 0

        \[\leadsto \color{blue}{\frac{-1}{4} \cdot {i}^{2}} \]
      6. Step-by-step derivation
        1. unpow2N/A

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

          \[\leadsto \left(\frac{-1}{4} \cdot i\right) \cdot \color{blue}{i} \]
        3. *-commutativeN/A

          \[\leadsto i \cdot \color{blue}{\left(\frac{-1}{4} \cdot i\right)} \]
        4. *-lowering-*.f64N/A

          \[\leadsto \mathsf{*.f64}\left(i, \color{blue}{\left(\frac{-1}{4} \cdot i\right)}\right) \]
        5. *-commutativeN/A

          \[\leadsto \mathsf{*.f64}\left(i, \left(i \cdot \color{blue}{\frac{-1}{4}}\right)\right) \]
        6. *-lowering-*.f6498.7%

          \[\leadsto \mathsf{*.f64}\left(i, \mathsf{*.f64}\left(i, \color{blue}{\frac{-1}{4}}\right)\right) \]
      7. Simplified98.7%

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

      if 0.5 < i

      1. Initial program 20.3%

        \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. Step-by-step derivation
        1. associate-/l/N/A

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

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

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

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

          \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
        6. times-fracN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
        7. *-inversesN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
        8. *-rgt-identityN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
        9. associate-/l/N/A

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

          \[\leadsto \frac{\frac{\left(i \cdot i\right) \cdot i}{\left(2 \cdot i\right) \cdot 2}}{\color{blue}{\left(2 \cdot i\right)} \cdot \left(2 \cdot i\right) - 1} \]
      3. Simplified46.6%

        \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
      4. Add Preprocessing
      5. Taylor expanded in i around inf

        \[\leadsto \color{blue}{\frac{1}{16}} \]
      6. Step-by-step derivation
        1. Simplified100.0%

          \[\leadsto \color{blue}{0.0625} \]
      7. Recombined 2 regimes into one program.
      8. Add Preprocessing

      Alternative 4: 50.5% 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 26.9%

        \[\frac{\frac{\left(i \cdot i\right) \cdot \left(i \cdot i\right)}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right)}}{\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1} \]
      2. Step-by-step derivation
        1. associate-/l/N/A

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

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

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

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

          \[\leadsto \frac{\left(i \cdot \left(i \cdot i\right)\right) \cdot i}{\left(\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)\right) \cdot \color{blue}{i}} \]
        6. times-fracN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot \color{blue}{\frac{i}{i}} \]
        7. *-inversesN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)} \cdot 1 \]
        8. *-rgt-identityN/A

          \[\leadsto \frac{i \cdot \left(i \cdot i\right)}{\color{blue}{\left(\left(2 \cdot i\right) \cdot \left(2 \cdot i\right) - 1\right) \cdot \left(\left(2 \cdot i\right) \cdot 2\right)}} \]
        9. associate-/l/N/A

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

          \[\leadsto \frac{\frac{\left(i \cdot i\right) \cdot i}{\left(2 \cdot i\right) \cdot 2}}{\color{blue}{\left(2 \cdot i\right)} \cdot \left(2 \cdot i\right) - 1} \]
      3. Simplified75.4%

        \[\leadsto \color{blue}{\frac{i \cdot i}{\left(\left(i \cdot i\right) \cdot 4\right) \cdot 4 + -4}} \]
      4. Add Preprocessing
      5. Taylor expanded in i around inf

        \[\leadsto \color{blue}{\frac{1}{16}} \]
      6. Step-by-step derivation
        1. Simplified47.5%

          \[\leadsto \color{blue}{0.0625} \]
        2. Add Preprocessing

        Reproduce

        ?
        herbie shell --seed 2024164 
        (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)))