Jmat.Real.lambertw, newton loop step

Percentage Accurate: 78.0% → 99.6%
Time: 15.0s
Alternatives: 15
Speedup: 313.0×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_0 := wj \cdot e^{wj}\\ wj - \frac{t\_0 - x}{e^{wj} + t\_0} \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (* wj (exp wj)))) (- wj (/ (- t_0 x) (+ (exp wj) t_0)))))
double code(double wj, double x) {
	double t_0 = wj * exp(wj);
	return wj - ((t_0 - x) / (exp(wj) + t_0));
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: t_0
    t_0 = wj * exp(wj)
    code = wj - ((t_0 - x) / (exp(wj) + t_0))
end function
public static double code(double wj, double x) {
	double t_0 = wj * Math.exp(wj);
	return wj - ((t_0 - x) / (Math.exp(wj) + t_0));
}
def code(wj, x):
	t_0 = wj * math.exp(wj)
	return wj - ((t_0 - x) / (math.exp(wj) + t_0))
function code(wj, x)
	t_0 = Float64(wj * exp(wj))
	return Float64(wj - Float64(Float64(t_0 - x) / Float64(exp(wj) + t_0)))
end
function tmp = code(wj, x)
	t_0 = wj * exp(wj);
	tmp = wj - ((t_0 - x) / (exp(wj) + t_0));
end
code[wj_, x_] := Block[{t$95$0 = N[(wj * N[Exp[wj], $MachinePrecision]), $MachinePrecision]}, N[(wj - N[(N[(t$95$0 - x), $MachinePrecision] / N[(N[Exp[wj], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := wj \cdot e^{wj}\\
wj - \frac{t\_0 - x}{e^{wj} + t\_0}
\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 15 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: 78.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := wj \cdot e^{wj}\\ wj - \frac{t\_0 - x}{e^{wj} + t\_0} \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (* wj (exp wj)))) (- wj (/ (- t_0 x) (+ (exp wj) t_0)))))
double code(double wj, double x) {
	double t_0 = wj * exp(wj);
	return wj - ((t_0 - x) / (exp(wj) + t_0));
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: t_0
    t_0 = wj * exp(wj)
    code = wj - ((t_0 - x) / (exp(wj) + t_0))
end function
public static double code(double wj, double x) {
	double t_0 = wj * Math.exp(wj);
	return wj - ((t_0 - x) / (Math.exp(wj) + t_0));
}
def code(wj, x):
	t_0 = wj * math.exp(wj)
	return wj - ((t_0 - x) / (math.exp(wj) + t_0))
function code(wj, x)
	t_0 = Float64(wj * exp(wj))
	return Float64(wj - Float64(Float64(t_0 - x) / Float64(exp(wj) + t_0)))
end
function tmp = code(wj, x)
	t_0 = wj * exp(wj);
	tmp = wj - ((t_0 - x) / (exp(wj) + t_0));
end
code[wj_, x_] := Block[{t$95$0 = N[(wj * N[Exp[wj], $MachinePrecision]), $MachinePrecision]}, N[(wj - N[(N[(t$95$0 - x), $MachinePrecision] / N[(N[Exp[wj], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := wj \cdot e^{wj}\\
wj - \frac{t\_0 - x}{e^{wj} + t\_0}
\end{array}
\end{array}

Alternative 1: 99.6% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := wj - \frac{x}{e^{wj}}\\ t_1 := \frac{t\_0}{wj + 1}\\ t_2 := x \cdot -4 + x \cdot 1.5\\ \mathbf{if}\;wj \leq -3.5 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_2 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_2 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(wj - t\_1\right) + \mathsf{fma}\left(\frac{-1}{wj + 1}, t\_0, t\_1\right)\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (- wj (/ x (exp wj))))
        (t_1 (/ t_0 (+ wj 1.0)))
        (t_2 (+ (* x -4.0) (* x 1.5))))
   (if (<= wj -3.5e-6)
     (*
      x
      (+ (/ (exp (- wj)) (+ wj 1.0)) (+ (/ wj x) (/ wj (* x (- -1.0 wj))))))
     (if (<= wj 3.55e-6)
       (-
        x
        (*
         wj
         (+
          (* x 2.0)
          (*
           wj
           (+
            t_2
            (+
             -1.0
             (*
              wj
              (+
               1.0
               (+ (* x -3.0) (+ (* -2.0 t_2) (* x 0.6666666666666666)))))))))))
       (+ (- wj t_1) (fma (/ -1.0 (+ wj 1.0)) t_0 t_1))))))
double code(double wj, double x) {
	double t_0 = wj - (x / exp(wj));
	double t_1 = t_0 / (wj + 1.0);
	double t_2 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= -3.5e-6) {
		tmp = x * ((exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))));
	} else if (wj <= 3.55e-6) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_2 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_2) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = (wj - t_1) + fma((-1.0 / (wj + 1.0)), t_0, t_1);
	}
	return tmp;
}
function code(wj, x)
	t_0 = Float64(wj - Float64(x / exp(wj)))
	t_1 = Float64(t_0 / Float64(wj + 1.0))
	t_2 = Float64(Float64(x * -4.0) + Float64(x * 1.5))
	tmp = 0.0
	if (wj <= -3.5e-6)
		tmp = Float64(x * Float64(Float64(exp(Float64(-wj)) / Float64(wj + 1.0)) + Float64(Float64(wj / x) + Float64(wj / Float64(x * Float64(-1.0 - wj))))));
	elseif (wj <= 3.55e-6)
		tmp = Float64(x - Float64(wj * Float64(Float64(x * 2.0) + Float64(wj * Float64(t_2 + Float64(-1.0 + Float64(wj * Float64(1.0 + Float64(Float64(x * -3.0) + Float64(Float64(-2.0 * t_2) + Float64(x * 0.6666666666666666)))))))))));
	else
		tmp = Float64(Float64(wj - t_1) + fma(Float64(-1.0 / Float64(wj + 1.0)), t_0, t_1));
	end
	return tmp
end
code[wj_, x_] := Block[{t$95$0 = N[(wj - N[(x / N[Exp[wj], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(t$95$0 / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[(x * -4.0), $MachinePrecision] + N[(x * 1.5), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[wj, -3.5e-6], N[(x * N[(N[(N[Exp[(-wj)], $MachinePrecision] / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(wj / x), $MachinePrecision] + N[(wj / N[(x * N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[wj, 3.55e-6], N[(x - N[(wj * N[(N[(x * 2.0), $MachinePrecision] + N[(wj * N[(t$95$2 + N[(-1.0 + N[(wj * N[(1.0 + N[(N[(x * -3.0), $MachinePrecision] + N[(N[(-2.0 * t$95$2), $MachinePrecision] + N[(x * 0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(wj - t$95$1), $MachinePrecision] + N[(N[(-1.0 / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision] * t$95$0 + t$95$1), $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := wj - \frac{x}{e^{wj}}\\
t_1 := \frac{t\_0}{wj + 1}\\
t_2 := x \cdot -4 + x \cdot 1.5\\
\mathbf{if}\;wj \leq -3.5 \cdot 10^{-6}:\\
\;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\

\mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\
\;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_2 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_2 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\left(wj - t\_1\right) + \mathsf{fma}\left(\frac{-1}{wj + 1}, t\_0, t\_1\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if wj < -3.49999999999999995e-6

    1. Initial program 85.3%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in99.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/99.6%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub85.3%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*85.3%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses99.6%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity99.6%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.6%

      \[\leadsto \color{blue}{x \cdot \left(\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \frac{wj}{x}\right) - \frac{wj}{x \cdot \left(1 + wj\right)}\right)} \]
    6. Step-by-step derivation
      1. associate--l+99.6%

        \[\leadsto x \cdot \color{blue}{\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right)} \]
      2. associate-/r*99.8%

        \[\leadsto x \cdot \left(\color{blue}{\frac{\frac{1}{e^{wj}}}{1 + wj}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      3. rec-exp99.8%

        \[\leadsto x \cdot \left(\frac{\color{blue}{e^{-wj}}}{1 + wj} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{\color{blue}{wj + 1}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      5. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \color{blue}{\left(wj + 1\right)}}\right)\right) \]
    7. Simplified99.8%

      \[\leadsto \color{blue}{x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(wj + 1\right)}\right)\right)} \]

    if -3.49999999999999995e-6 < wj < 3.5499999999999999e-6

    1. Initial program 74.0%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.0%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.0%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.0%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 99.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]

    if 3.5499999999999999e-6 < wj

    1. Initial program 44.6%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in44.4%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/44.5%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub44.5%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*44.5%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses98.4%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity98.4%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified98.4%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. *-un-lft-identity98.4%

        \[\leadsto \color{blue}{1 \cdot wj} - \frac{wj - \frac{x}{e^{wj}}}{wj + 1} \]
      2. div-inv98.3%

        \[\leadsto 1 \cdot wj - \color{blue}{\left(wj - \frac{x}{e^{wj}}\right) \cdot \frac{1}{wj + 1}} \]
      3. prod-diff98.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(1, wj, -\frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right)} \]
      4. associate-/r/98.1%

        \[\leadsto \mathsf{fma}\left(1, wj, -\color{blue}{\frac{1}{\frac{wj + 1}{wj - \frac{x}{e^{wj}}}}}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right) \]
      5. clear-num98.2%

        \[\leadsto \mathsf{fma}\left(1, wj, -\color{blue}{\frac{wj - \frac{x}{e^{wj}}}{wj + 1}}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right) \]
      6. fma-neg98.2%

        \[\leadsto \color{blue}{\left(1 \cdot wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right)} + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right) \]
      7. *-un-lft-identity98.2%

        \[\leadsto \left(\color{blue}{wj} - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{1}{wj + 1} \cdot \left(wj - \frac{x}{e^{wj}}\right)\right) \]
      8. associate-/r/98.4%

        \[\leadsto \left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \color{blue}{\frac{1}{\frac{wj + 1}{wj - \frac{x}{e^{wj}}}}}\right) \]
      9. clear-num98.5%

        \[\leadsto \left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \color{blue}{\frac{wj - \frac{x}{e^{wj}}}{wj + 1}}\right) \]
    6. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(-\frac{1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac98.5%

        \[\leadsto \left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(\color{blue}{\frac{-1}{wj + 1}}, wj - \frac{x}{e^{wj}}, \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) \]
      2. metadata-eval98.5%

        \[\leadsto \left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(\frac{\color{blue}{-1}}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) \]
    8. Simplified98.5%

      \[\leadsto \color{blue}{\left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(\frac{-1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq -3.5 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(\left(x \cdot -4 + x \cdot 1.5\right) + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot \left(x \cdot -4 + x \cdot 1.5\right) + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right) + \mathsf{fma}\left(\frac{-1}{wj + 1}, wj - \frac{x}{e^{wj}}, \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.6% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot -4 + x \cdot 1.5\\ \mathbf{if}\;wj \leq -4.3 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 6.2 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \left(1 - wj\right)\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (+ (* x -4.0) (* x 1.5))))
   (if (<= wj -4.3e-6)
     (*
      x
      (+ (/ (exp (- wj)) (+ wj 1.0)) (+ (/ wj x) (/ wj (* x (- -1.0 wj))))))
     (if (<= wj 6.2e-6)
       (-
        x
        (*
         wj
         (+
          (* x 2.0)
          (*
           wj
           (+
            t_0
            (+
             -1.0
             (*
              wj
              (+
               1.0
               (+ (* x -3.0) (+ (* -2.0 t_0) (* x 0.6666666666666666)))))))))))
       (+ wj (* (/ (- wj (/ x (exp wj))) (fma wj wj -1.0)) (- 1.0 wj)))))))
double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= -4.3e-6) {
		tmp = x * ((exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))));
	} else if (wj <= 6.2e-6) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = wj + (((wj - (x / exp(wj))) / fma(wj, wj, -1.0)) * (1.0 - wj));
	}
	return tmp;
}
function code(wj, x)
	t_0 = Float64(Float64(x * -4.0) + Float64(x * 1.5))
	tmp = 0.0
	if (wj <= -4.3e-6)
		tmp = Float64(x * Float64(Float64(exp(Float64(-wj)) / Float64(wj + 1.0)) + Float64(Float64(wj / x) + Float64(wj / Float64(x * Float64(-1.0 - wj))))));
	elseif (wj <= 6.2e-6)
		tmp = Float64(x - Float64(wj * Float64(Float64(x * 2.0) + Float64(wj * Float64(t_0 + Float64(-1.0 + Float64(wj * Float64(1.0 + Float64(Float64(x * -3.0) + Float64(Float64(-2.0 * t_0) + Float64(x * 0.6666666666666666)))))))))));
	else
		tmp = Float64(wj + Float64(Float64(Float64(wj - Float64(x / exp(wj))) / fma(wj, wj, -1.0)) * Float64(1.0 - wj)));
	end
	return tmp
end
code[wj_, x_] := Block[{t$95$0 = N[(N[(x * -4.0), $MachinePrecision] + N[(x * 1.5), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[wj, -4.3e-6], N[(x * N[(N[(N[Exp[(-wj)], $MachinePrecision] / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(wj / x), $MachinePrecision] + N[(wj / N[(x * N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[wj, 6.2e-6], N[(x - N[(wj * N[(N[(x * 2.0), $MachinePrecision] + N[(wj * N[(t$95$0 + N[(-1.0 + N[(wj * N[(1.0 + N[(N[(x * -3.0), $MachinePrecision] + N[(N[(-2.0 * t$95$0), $MachinePrecision] + N[(x * 0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(N[(N[(wj - N[(x / N[Exp[wj], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(wj * wj + -1.0), $MachinePrecision]), $MachinePrecision] * N[(1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot -4 + x \cdot 1.5\\
\mathbf{if}\;wj \leq -4.3 \cdot 10^{-6}:\\
\;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\

\mathbf{elif}\;wj \leq 6.2 \cdot 10^{-6}:\\
\;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \left(1 - wj\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if wj < -4.30000000000000033e-6

    1. Initial program 85.3%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in99.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/99.6%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub85.3%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*85.3%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses99.6%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity99.6%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.6%

      \[\leadsto \color{blue}{x \cdot \left(\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \frac{wj}{x}\right) - \frac{wj}{x \cdot \left(1 + wj\right)}\right)} \]
    6. Step-by-step derivation
      1. associate--l+99.6%

        \[\leadsto x \cdot \color{blue}{\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right)} \]
      2. associate-/r*99.8%

        \[\leadsto x \cdot \left(\color{blue}{\frac{\frac{1}{e^{wj}}}{1 + wj}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      3. rec-exp99.8%

        \[\leadsto x \cdot \left(\frac{\color{blue}{e^{-wj}}}{1 + wj} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{\color{blue}{wj + 1}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      5. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \color{blue}{\left(wj + 1\right)}}\right)\right) \]
    7. Simplified99.8%

      \[\leadsto \color{blue}{x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(wj + 1\right)}\right)\right)} \]

    if -4.30000000000000033e-6 < wj < 6.1999999999999999e-6

    1. Initial program 74.0%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.0%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.0%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.0%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 99.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]

    if 6.1999999999999999e-6 < wj

    1. Initial program 44.6%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in44.4%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/44.5%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub44.5%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*44.5%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses98.4%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity98.4%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified98.4%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. flip-+98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{\color{blue}{\frac{wj \cdot wj - 1 \cdot 1}{wj - 1}}} \]
      2. associate-/r/98.5%

        \[\leadsto wj - \color{blue}{\frac{wj - \frac{x}{e^{wj}}}{wj \cdot wj - 1 \cdot 1} \cdot \left(wj - 1\right)} \]
      3. metadata-eval98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{wj \cdot wj - \color{blue}{1}} \cdot \left(wj - 1\right) \]
      4. fma-neg98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{\color{blue}{\mathsf{fma}\left(wj, wj, -1\right)}} \cdot \left(wj - 1\right) \]
      5. metadata-eval98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, \color{blue}{-1}\right)} \cdot \left(wj - 1\right) \]
      6. sub-neg98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \color{blue}{\left(wj + \left(-1\right)\right)} \]
      7. metadata-eval98.5%

        \[\leadsto wj - \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \left(wj + \color{blue}{-1}\right) \]
    6. Applied egg-rr98.5%

      \[\leadsto wj - \color{blue}{\frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \left(wj + -1\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq -4.3 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 6.2 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(\left(x \cdot -4 + x \cdot 1.5\right) + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot \left(x \cdot -4 + x \cdot 1.5\right) + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj - \frac{x}{e^{wj}}}{\mathsf{fma}\left(wj, wj, -1\right)} \cdot \left(1 - wj\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.6% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot -4 + x \cdot 1.5\\ \mathbf{if}\;wj \leq -3.2 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (+ (* x -4.0) (* x 1.5))))
   (if (<= wj -3.2e-6)
     (*
      x
      (+ (/ (exp (- wj)) (+ wj 1.0)) (+ (/ wj x) (/ wj (* x (- -1.0 wj))))))
     (if (<= wj 3.55e-6)
       (-
        x
        (*
         wj
         (+
          (* x 2.0)
          (*
           wj
           (+
            t_0
            (+
             -1.0
             (*
              wj
              (+
               1.0
               (+ (* x -3.0) (+ (* -2.0 t_0) (* x 0.6666666666666666)))))))))))
       (- wj (/ (- wj (/ x (exp wj))) (+ wj 1.0)))))))
double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= -3.2e-6) {
		tmp = x * ((exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))));
	} else if (wj <= 3.55e-6) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (x * (-4.0d0)) + (x * 1.5d0)
    if (wj <= (-3.2d-6)) then
        tmp = x * ((exp(-wj) / (wj + 1.0d0)) + ((wj / x) + (wj / (x * ((-1.0d0) - wj)))))
    else if (wj <= 3.55d-6) then
        tmp = x - (wj * ((x * 2.0d0) + (wj * (t_0 + ((-1.0d0) + (wj * (1.0d0 + ((x * (-3.0d0)) + (((-2.0d0) * t_0) + (x * 0.6666666666666666d0))))))))))
    else
        tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0d0))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= -3.2e-6) {
		tmp = x * ((Math.exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))));
	} else if (wj <= 3.55e-6) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = wj - ((wj - (x / Math.exp(wj))) / (wj + 1.0));
	}
	return tmp;
}
def code(wj, x):
	t_0 = (x * -4.0) + (x * 1.5)
	tmp = 0
	if wj <= -3.2e-6:
		tmp = x * ((math.exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))))
	elif wj <= 3.55e-6:
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))))
	else:
		tmp = wj - ((wj - (x / math.exp(wj))) / (wj + 1.0))
	return tmp
function code(wj, x)
	t_0 = Float64(Float64(x * -4.0) + Float64(x * 1.5))
	tmp = 0.0
	if (wj <= -3.2e-6)
		tmp = Float64(x * Float64(Float64(exp(Float64(-wj)) / Float64(wj + 1.0)) + Float64(Float64(wj / x) + Float64(wj / Float64(x * Float64(-1.0 - wj))))));
	elseif (wj <= 3.55e-6)
		tmp = Float64(x - Float64(wj * Float64(Float64(x * 2.0) + Float64(wj * Float64(t_0 + Float64(-1.0 + Float64(wj * Float64(1.0 + Float64(Float64(x * -3.0) + Float64(Float64(-2.0 * t_0) + Float64(x * 0.6666666666666666)))))))))));
	else
		tmp = Float64(wj - Float64(Float64(wj - Float64(x / exp(wj))) / Float64(wj + 1.0)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	t_0 = (x * -4.0) + (x * 1.5);
	tmp = 0.0;
	if (wj <= -3.2e-6)
		tmp = x * ((exp(-wj) / (wj + 1.0)) + ((wj / x) + (wj / (x * (-1.0 - wj)))));
	elseif (wj <= 3.55e-6)
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	else
		tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := Block[{t$95$0 = N[(N[(x * -4.0), $MachinePrecision] + N[(x * 1.5), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[wj, -3.2e-6], N[(x * N[(N[(N[Exp[(-wj)], $MachinePrecision] / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[(wj / x), $MachinePrecision] + N[(wj / N[(x * N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[wj, 3.55e-6], N[(x - N[(wj * N[(N[(x * 2.0), $MachinePrecision] + N[(wj * N[(t$95$0 + N[(-1.0 + N[(wj * N[(1.0 + N[(N[(x * -3.0), $MachinePrecision] + N[(N[(-2.0 * t$95$0), $MachinePrecision] + N[(x * 0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj - N[(N[(wj - N[(x / N[Exp[wj], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot -4 + x \cdot 1.5\\
\mathbf{if}\;wj \leq -3.2 \cdot 10^{-6}:\\
\;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\

\mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\
\;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if wj < -3.1999999999999999e-6

    1. Initial program 85.3%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in99.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/99.6%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub85.3%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*85.3%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses99.6%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity99.6%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 99.6%

      \[\leadsto \color{blue}{x \cdot \left(\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \frac{wj}{x}\right) - \frac{wj}{x \cdot \left(1 + wj\right)}\right)} \]
    6. Step-by-step derivation
      1. associate--l+99.6%

        \[\leadsto x \cdot \color{blue}{\left(\frac{1}{e^{wj} \cdot \left(1 + wj\right)} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right)} \]
      2. associate-/r*99.8%

        \[\leadsto x \cdot \left(\color{blue}{\frac{\frac{1}{e^{wj}}}{1 + wj}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      3. rec-exp99.8%

        \[\leadsto x \cdot \left(\frac{\color{blue}{e^{-wj}}}{1 + wj} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{\color{blue}{wj + 1}} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(1 + wj\right)}\right)\right) \]
      5. +-commutative99.8%

        \[\leadsto x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \color{blue}{\left(wj + 1\right)}}\right)\right) \]
    7. Simplified99.8%

      \[\leadsto \color{blue}{x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} - \frac{wj}{x \cdot \left(wj + 1\right)}\right)\right)} \]

    if -3.1999999999999999e-6 < wj < 3.5499999999999999e-6

    1. Initial program 74.0%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.0%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.0%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.0%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 99.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]

    if 3.5499999999999999e-6 < wj

    1. Initial program 44.6%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in44.4%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/44.5%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub44.5%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*44.5%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses98.4%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity98.4%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified98.4%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
  3. Recombined 3 regimes into one program.
  4. Final simplification99.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq -3.2 \cdot 10^{-6}:\\ \;\;\;\;x \cdot \left(\frac{e^{-wj}}{wj + 1} + \left(\frac{wj}{x} + \frac{wj}{x \cdot \left(-1 - wj\right)}\right)\right)\\ \mathbf{elif}\;wj \leq 3.55 \cdot 10^{-6}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(\left(x \cdot -4 + x \cdot 1.5\right) + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot \left(x \cdot -4 + x \cdot 1.5\right) + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.6% accurate, 2.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot -4 + x \cdot 1.5\\ \mathbf{if}\;wj \leq -3.5 \cdot 10^{-6} \lor \neg \left(wj \leq 5.5 \cdot 10^{-6}\right):\\ \;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\ \mathbf{else}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (+ (* x -4.0) (* x 1.5))))
   (if (or (<= wj -3.5e-6) (not (<= wj 5.5e-6)))
     (- wj (/ (- wj (/ x (exp wj))) (+ wj 1.0)))
     (-
      x
      (*
       wj
       (+
        (* x 2.0)
        (*
         wj
         (+
          t_0
          (+
           -1.0
           (*
            wj
            (+
             1.0
             (+
              (* x -3.0)
              (+ (* -2.0 t_0) (* x 0.6666666666666666))))))))))))))
double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if ((wj <= -3.5e-6) || !(wj <= 5.5e-6)) {
		tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0));
	} else {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (x * (-4.0d0)) + (x * 1.5d0)
    if ((wj <= (-3.5d-6)) .or. (.not. (wj <= 5.5d-6))) then
        tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0d0))
    else
        tmp = x - (wj * ((x * 2.0d0) + (wj * (t_0 + ((-1.0d0) + (wj * (1.0d0 + ((x * (-3.0d0)) + (((-2.0d0) * t_0) + (x * 0.6666666666666666d0))))))))))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if ((wj <= -3.5e-6) || !(wj <= 5.5e-6)) {
		tmp = wj - ((wj - (x / Math.exp(wj))) / (wj + 1.0));
	} else {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	}
	return tmp;
}
def code(wj, x):
	t_0 = (x * -4.0) + (x * 1.5)
	tmp = 0
	if (wj <= -3.5e-6) or not (wj <= 5.5e-6):
		tmp = wj - ((wj - (x / math.exp(wj))) / (wj + 1.0))
	else:
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))))
	return tmp
function code(wj, x)
	t_0 = Float64(Float64(x * -4.0) + Float64(x * 1.5))
	tmp = 0.0
	if ((wj <= -3.5e-6) || !(wj <= 5.5e-6))
		tmp = Float64(wj - Float64(Float64(wj - Float64(x / exp(wj))) / Float64(wj + 1.0)));
	else
		tmp = Float64(x - Float64(wj * Float64(Float64(x * 2.0) + Float64(wj * Float64(t_0 + Float64(-1.0 + Float64(wj * Float64(1.0 + Float64(Float64(x * -3.0) + Float64(Float64(-2.0 * t_0) + Float64(x * 0.6666666666666666)))))))))));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	t_0 = (x * -4.0) + (x * 1.5);
	tmp = 0.0;
	if ((wj <= -3.5e-6) || ~((wj <= 5.5e-6)))
		tmp = wj - ((wj - (x / exp(wj))) / (wj + 1.0));
	else
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := Block[{t$95$0 = N[(N[(x * -4.0), $MachinePrecision] + N[(x * 1.5), $MachinePrecision]), $MachinePrecision]}, If[Or[LessEqual[wj, -3.5e-6], N[Not[LessEqual[wj, 5.5e-6]], $MachinePrecision]], N[(wj - N[(N[(wj - N[(x / N[Exp[wj], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x - N[(wj * N[(N[(x * 2.0), $MachinePrecision] + N[(wj * N[(t$95$0 + N[(-1.0 + N[(wj * N[(1.0 + N[(N[(x * -3.0), $MachinePrecision] + N[(N[(-2.0 * t$95$0), $MachinePrecision] + N[(x * 0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot -4 + x \cdot 1.5\\
\mathbf{if}\;wj \leq -3.5 \cdot 10^{-6} \lor \neg \left(wj \leq 5.5 \cdot 10^{-6}\right):\\
\;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\

\mathbf{else}:\\
\;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < -3.49999999999999995e-6 or 5.4999999999999999e-6 < wj

    1. Initial program 58.8%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in63.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/63.8%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub58.8%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*58.8%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses98.8%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity98.8%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified98.8%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing

    if -3.49999999999999995e-6 < wj < 5.4999999999999999e-6

    1. Initial program 74.0%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.0%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.0%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.0%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 99.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq -3.5 \cdot 10^{-6} \lor \neg \left(wj \leq 5.5 \cdot 10^{-6}\right):\\ \;\;\;\;wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}\\ \mathbf{else}:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(\left(x \cdot -4 + x \cdot 1.5\right) + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot \left(x \cdot -4 + x \cdot 1.5\right) + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 97.4% accurate, 6.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := x \cdot -4 + x \cdot 1.5\\ \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (let* ((t_0 (+ (* x -4.0) (* x 1.5))))
   (if (<= wj 0.24)
     (-
      x
      (*
       wj
       (+
        (* x 2.0)
        (*
         wj
         (+
          t_0
          (+
           -1.0
           (*
            wj
            (+
             1.0
             (+ (* x -3.0) (+ (* -2.0 t_0) (* x 0.6666666666666666)))))))))))
     (+ wj (/ wj (- -1.0 wj))))))
double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= 0.24) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (x * (-4.0d0)) + (x * 1.5d0)
    if (wj <= 0.24d0) then
        tmp = x - (wj * ((x * 2.0d0) + (wj * (t_0 + ((-1.0d0) + (wj * (1.0d0 + ((x * (-3.0d0)) + (((-2.0d0) * t_0) + (x * 0.6666666666666666d0))))))))))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double t_0 = (x * -4.0) + (x * 1.5);
	double tmp;
	if (wj <= 0.24) {
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	t_0 = (x * -4.0) + (x * 1.5)
	tmp = 0
	if wj <= 0.24:
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	t_0 = Float64(Float64(x * -4.0) + Float64(x * 1.5))
	tmp = 0.0
	if (wj <= 0.24)
		tmp = Float64(x - Float64(wj * Float64(Float64(x * 2.0) + Float64(wj * Float64(t_0 + Float64(-1.0 + Float64(wj * Float64(1.0 + Float64(Float64(x * -3.0) + Float64(Float64(-2.0 * t_0) + Float64(x * 0.6666666666666666)))))))))));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	t_0 = (x * -4.0) + (x * 1.5);
	tmp = 0.0;
	if (wj <= 0.24)
		tmp = x - (wj * ((x * 2.0) + (wj * (t_0 + (-1.0 + (wj * (1.0 + ((x * -3.0) + ((-2.0 * t_0) + (x * 0.6666666666666666))))))))));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := Block[{t$95$0 = N[(N[(x * -4.0), $MachinePrecision] + N[(x * 1.5), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[wj, 0.24], N[(x - N[(wj * N[(N[(x * 2.0), $MachinePrecision] + N[(wj * N[(t$95$0 + N[(-1.0 + N[(wj * N[(1.0 + N[(N[(x * -3.0), $MachinePrecision] + N[(N[(-2.0 * t$95$0), $MachinePrecision] + N[(x * 0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := x \cdot -4 + x \cdot 1.5\\
\mathbf{if}\;wj \leq 0.24:\\
\;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(t\_0 + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot t\_0 + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 0.23999999999999999

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 96.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]

    if 0.23999999999999999 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x - wj \cdot \left(x \cdot 2 + wj \cdot \left(\left(x \cdot -4 + x \cdot 1.5\right) + \left(-1 + wj \cdot \left(1 + \left(x \cdot -3 + \left(-2 \cdot \left(x \cdot -4 + x \cdot 1.5\right) + x \cdot 0.6666666666666666\right)\right)\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 97.5% accurate, 10.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \left(\frac{1}{x} + wj \cdot \left(\frac{-1}{x} - 2.6666666666666665\right)\right)\right)\right) - x \cdot 2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 0.24)
   (+
    x
    (*
     wj
     (-
      (*
       x
       (* wj (+ 2.5 (+ (/ 1.0 x) (* wj (- (/ -1.0 x) 2.6666666666666665))))))
      (* x 2.0))))
   (+ wj (/ wj (- -1.0 wj)))))
double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * ((x * (wj * (2.5 + ((1.0 / x) + (wj * ((-1.0 / x) - 2.6666666666666665)))))) - (x * 2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 0.24d0) then
        tmp = x + (wj * ((x * (wj * (2.5d0 + ((1.0d0 / x) + (wj * (((-1.0d0) / x) - 2.6666666666666665d0)))))) - (x * 2.0d0)))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * ((x * (wj * (2.5 + ((1.0 / x) + (wj * ((-1.0 / x) - 2.6666666666666665)))))) - (x * 2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 0.24:
		tmp = x + (wj * ((x * (wj * (2.5 + ((1.0 / x) + (wj * ((-1.0 / x) - 2.6666666666666665)))))) - (x * 2.0)))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 0.24)
		tmp = Float64(x + Float64(wj * Float64(Float64(x * Float64(wj * Float64(2.5 + Float64(Float64(1.0 / x) + Float64(wj * Float64(Float64(-1.0 / x) - 2.6666666666666665)))))) - Float64(x * 2.0))));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 0.24)
		tmp = x + (wj * ((x * (wj * (2.5 + ((1.0 / x) + (wj * ((-1.0 / x) - 2.6666666666666665)))))) - (x * 2.0)));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 0.24], N[(x + N[(wj * N[(N[(x * N[(wj * N[(2.5 + N[(N[(1.0 / x), $MachinePrecision] + N[(wj * N[(N[(-1.0 / x), $MachinePrecision] - 2.6666666666666665), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(x * 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 0.24:\\
\;\;\;\;x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \left(\frac{1}{x} + wj \cdot \left(\frac{-1}{x} - 2.6666666666666665\right)\right)\right)\right) - x \cdot 2\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 0.23999999999999999

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 96.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]
    6. Taylor expanded in x around inf 96.9%

      \[\leadsto x + wj \cdot \left(\color{blue}{x \cdot \left(wj \cdot \left(2.5 + -2.6666666666666665 \cdot wj\right) + \frac{wj \cdot \left(1 + -1 \cdot wj\right)}{x}\right)} - 2 \cdot x\right) \]
    7. Step-by-step derivation
      1. fma-define96.9%

        \[\leadsto x + wj \cdot \left(x \cdot \color{blue}{\mathsf{fma}\left(wj, 2.5 + -2.6666666666666665 \cdot wj, \frac{wj \cdot \left(1 + -1 \cdot wj\right)}{x}\right)} - 2 \cdot x\right) \]
      2. *-commutative96.9%

        \[\leadsto x + wj \cdot \left(x \cdot \mathsf{fma}\left(wj, 2.5 + \color{blue}{wj \cdot -2.6666666666666665}, \frac{wj \cdot \left(1 + -1 \cdot wj\right)}{x}\right) - 2 \cdot x\right) \]
      3. associate-/l*96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \mathsf{fma}\left(wj, 2.5 + wj \cdot -2.6666666666666665, \color{blue}{wj \cdot \frac{1 + -1 \cdot wj}{x}}\right) - 2 \cdot x\right) \]
      4. mul-1-neg96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \mathsf{fma}\left(wj, 2.5 + wj \cdot -2.6666666666666665, wj \cdot \frac{1 + \color{blue}{\left(-wj\right)}}{x}\right) - 2 \cdot x\right) \]
      5. sub-neg96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \mathsf{fma}\left(wj, 2.5 + wj \cdot -2.6666666666666665, wj \cdot \frac{\color{blue}{1 - wj}}{x}\right) - 2 \cdot x\right) \]
    8. Simplified96.8%

      \[\leadsto x + wj \cdot \left(\color{blue}{x \cdot \mathsf{fma}\left(wj, 2.5 + wj \cdot -2.6666666666666665, wj \cdot \frac{1 - wj}{x}\right)} - 2 \cdot x\right) \]
    9. Taylor expanded in wj around 0 96.8%

      \[\leadsto x + wj \cdot \left(x \cdot \color{blue}{\left(wj \cdot \left(2.5 + \left(-1 \cdot \left(wj \cdot \left(2.6666666666666665 + \frac{1}{x}\right)\right) + \frac{1}{x}\right)\right)\right)} - 2 \cdot x\right) \]
    10. Step-by-step derivation
      1. +-commutative96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \color{blue}{\left(\frac{1}{x} + -1 \cdot \left(wj \cdot \left(2.6666666666666665 + \frac{1}{x}\right)\right)\right)}\right)\right) - 2 \cdot x\right) \]
      2. mul-1-neg96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \left(\frac{1}{x} + \color{blue}{\left(-wj \cdot \left(2.6666666666666665 + \frac{1}{x}\right)\right)}\right)\right)\right) - 2 \cdot x\right) \]
      3. unsub-neg96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \color{blue}{\left(\frac{1}{x} - wj \cdot \left(2.6666666666666665 + \frac{1}{x}\right)\right)}\right)\right) - 2 \cdot x\right) \]
      4. +-commutative96.8%

        \[\leadsto x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \left(\frac{1}{x} - wj \cdot \color{blue}{\left(\frac{1}{x} + 2.6666666666666665\right)}\right)\right)\right) - 2 \cdot x\right) \]
    11. Simplified96.8%

      \[\leadsto x + wj \cdot \left(x \cdot \color{blue}{\left(wj \cdot \left(2.5 + \left(\frac{1}{x} - wj \cdot \left(\frac{1}{x} + 2.6666666666666665\right)\right)\right)\right)} - 2 \cdot x\right) \]

    if 0.23999999999999999 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(x \cdot \left(wj \cdot \left(2.5 + \left(\frac{1}{x} + wj \cdot \left(\frac{-1}{x} - 2.6666666666666665\right)\right)\right)\right) - x \cdot 2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 97.3% accurate, 17.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(wj \cdot \left(1 - wj\right) - x \cdot 2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 0.24)
   (+ x (* wj (- (* wj (- 1.0 wj)) (* x 2.0))))
   (+ wj (/ wj (- -1.0 wj)))))
double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * ((wj * (1.0 - wj)) - (x * 2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 0.24d0) then
        tmp = x + (wj * ((wj * (1.0d0 - wj)) - (x * 2.0d0)))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * ((wj * (1.0 - wj)) - (x * 2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 0.24:
		tmp = x + (wj * ((wj * (1.0 - wj)) - (x * 2.0)))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 0.24)
		tmp = Float64(x + Float64(wj * Float64(Float64(wj * Float64(1.0 - wj)) - Float64(x * 2.0))));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 0.24)
		tmp = x + (wj * ((wj * (1.0 - wj)) - (x * 2.0)));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 0.24], N[(x + N[(wj * N[(N[(wj * N[(1.0 - wj), $MachinePrecision]), $MachinePrecision] - N[(x * 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 0.24:\\
\;\;\;\;x + wj \cdot \left(wj \cdot \left(1 - wj\right) - x \cdot 2\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 0.23999999999999999

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 96.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]
    6. Taylor expanded in x around 0 96.4%

      \[\leadsto x + wj \cdot \left(\color{blue}{wj \cdot \left(1 + -1 \cdot wj\right)} - 2 \cdot x\right) \]
    7. Step-by-step derivation
      1. mul-1-neg96.4%

        \[\leadsto x + wj \cdot \left(wj \cdot \left(1 + \color{blue}{\left(-wj\right)}\right) - 2 \cdot x\right) \]
      2. sub-neg96.4%

        \[\leadsto x + wj \cdot \left(wj \cdot \color{blue}{\left(1 - wj\right)} - 2 \cdot x\right) \]
    8. Simplified96.4%

      \[\leadsto x + wj \cdot \left(\color{blue}{wj \cdot \left(1 - wj\right)} - 2 \cdot x\right) \]

    if 0.23999999999999999 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(wj \cdot \left(1 - wj\right) - x \cdot 2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 96.8% accurate, 22.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(wj + x \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 0.24) (+ x (* wj (+ wj (* x -2.0)))) (+ wj (/ wj (- -1.0 wj)))))
double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * (wj + (x * -2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 0.24d0) then
        tmp = x + (wj * (wj + (x * (-2.0d0))))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 0.24) {
		tmp = x + (wj * (wj + (x * -2.0)));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 0.24:
		tmp = x + (wj * (wj + (x * -2.0)))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 0.24)
		tmp = Float64(x + Float64(wj * Float64(wj + Float64(x * -2.0))));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 0.24)
		tmp = x + (wj * (wj + (x * -2.0)));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 0.24], N[(x + N[(wj * N[(wj + N[(x * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 0.24:\\
\;\;\;\;x + wj \cdot \left(wj + x \cdot -2\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 0.23999999999999999

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 96.9%

      \[\leadsto \color{blue}{x + wj \cdot \left(wj \cdot \left(\left(1 + -1 \cdot \left(wj \cdot \left(1 + \left(-3 \cdot x + \left(-2 \cdot \left(-4 \cdot x + 1.5 \cdot x\right) + 0.6666666666666666 \cdot x\right)\right)\right)\right)\right) - \left(-4 \cdot x + 1.5 \cdot x\right)\right) - 2 \cdot x\right)} \]
    6. Taylor expanded in x around 0 96.4%

      \[\leadsto x + wj \cdot \left(\color{blue}{wj \cdot \left(1 + -1 \cdot wj\right)} - 2 \cdot x\right) \]
    7. Step-by-step derivation
      1. mul-1-neg96.4%

        \[\leadsto x + wj \cdot \left(wj \cdot \left(1 + \color{blue}{\left(-wj\right)}\right) - 2 \cdot x\right) \]
      2. sub-neg96.4%

        \[\leadsto x + wj \cdot \left(wj \cdot \color{blue}{\left(1 - wj\right)} - 2 \cdot x\right) \]
    8. Simplified96.4%

      \[\leadsto x + wj \cdot \left(\color{blue}{wj \cdot \left(1 - wj\right)} - 2 \cdot x\right) \]
    9. Taylor expanded in wj around 0 96.0%

      \[\leadsto x + \color{blue}{wj \cdot \left(wj + -2 \cdot x\right)} \]
    10. Step-by-step derivation
      1. *-commutative96.0%

        \[\leadsto x + wj \cdot \left(wj + \color{blue}{x \cdot -2}\right) \]
    11. Simplified96.0%

      \[\leadsto x + \color{blue}{wj \cdot \left(wj + x \cdot -2\right)} \]

    if 0.23999999999999999 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 0.24:\\ \;\;\;\;x + wj \cdot \left(wj + x \cdot -2\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 85.9% accurate, 26.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\ \;\;\;\;\frac{x}{1 + wj \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 1.4e-7) (/ x (+ 1.0 (* wj 2.0))) (+ wj (/ wj (- -1.0 wj)))))
double code(double wj, double x) {
	double tmp;
	if (wj <= 1.4e-7) {
		tmp = x / (1.0 + (wj * 2.0));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 1.4d-7) then
        tmp = x / (1.0d0 + (wj * 2.0d0))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 1.4e-7) {
		tmp = x / (1.0 + (wj * 2.0));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 1.4e-7:
		tmp = x / (1.0 + (wj * 2.0))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 1.4e-7)
		tmp = Float64(x / Float64(1.0 + Float64(wj * 2.0)));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 1.4e-7)
		tmp = x / (1.0 + (wj * 2.0));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 1.4e-7], N[(x / N[(1.0 + N[(wj * 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\
\;\;\;\;\frac{x}{1 + wj \cdot 2}\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 1.4000000000000001e-7

    1. Initial program 74.4%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.8%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.4%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.4%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.8%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.8%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.8%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 84.4%

      \[\leadsto \color{blue}{\frac{x}{e^{wj} \cdot \left(1 + wj\right)}} \]
    6. Step-by-step derivation
      1. +-commutative84.4%

        \[\leadsto \frac{x}{e^{wj} \cdot \color{blue}{\left(wj + 1\right)}} \]
      2. rem-exp-log83.1%

        \[\leadsto \frac{x}{e^{wj} \cdot \color{blue}{e^{\log \left(wj + 1\right)}}} \]
      3. +-commutative83.1%

        \[\leadsto \frac{x}{e^{wj} \cdot e^{\log \color{blue}{\left(1 + wj\right)}}} \]
      4. log1p-undefine83.1%

        \[\leadsto \frac{x}{e^{wj} \cdot e^{\color{blue}{\mathsf{log1p}\left(wj\right)}}} \]
      5. exp-sum83.1%

        \[\leadsto \frac{x}{\color{blue}{e^{wj + \mathsf{log1p}\left(wj\right)}}} \]
    7. Simplified83.1%

      \[\leadsto \color{blue}{\frac{x}{e^{wj + \mathsf{log1p}\left(wj\right)}}} \]
    8. Taylor expanded in wj around 0 82.8%

      \[\leadsto \frac{x}{\color{blue}{1 + 2 \cdot wj}} \]
    9. Step-by-step derivation
      1. *-commutative82.8%

        \[\leadsto \frac{x}{1 + \color{blue}{wj \cdot 2}} \]
    10. Simplified82.8%

      \[\leadsto \frac{x}{\color{blue}{1 + wj \cdot 2}} \]

    if 1.4000000000000001e-7 < wj

    1. Initial program 46.1%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in46.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/46.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub46.1%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*46.1%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses96.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity96.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified96.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 75.6%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative75.6%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified75.6%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification82.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\ \;\;\;\;\frac{x}{1 + wj \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 10: 85.9% accurate, 26.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\ \;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 1.4e-7) (+ x (* -2.0 (* wj x))) (+ wj (/ wj (- -1.0 wj)))))
double code(double wj, double x) {
	double tmp;
	if (wj <= 1.4e-7) {
		tmp = x + (-2.0 * (wj * x));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 1.4d-7) then
        tmp = x + ((-2.0d0) * (wj * x))
    else
        tmp = wj + (wj / ((-1.0d0) - wj))
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 1.4e-7) {
		tmp = x + (-2.0 * (wj * x));
	} else {
		tmp = wj + (wj / (-1.0 - wj));
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 1.4e-7:
		tmp = x + (-2.0 * (wj * x))
	else:
		tmp = wj + (wj / (-1.0 - wj))
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 1.4e-7)
		tmp = Float64(x + Float64(-2.0 * Float64(wj * x)));
	else
		tmp = Float64(wj + Float64(wj / Float64(-1.0 - wj)));
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 1.4e-7)
		tmp = x + (-2.0 * (wj * x));
	else
		tmp = wj + (wj / (-1.0 - wj));
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 1.4e-7], N[(x + N[(-2.0 * N[(wj * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + N[(wj / N[(-1.0 - wj), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\
\;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\

\mathbf{else}:\\
\;\;\;\;wj + \frac{wj}{-1 - wj}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 1.4000000000000001e-7

    1. Initial program 74.4%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in74.8%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/74.8%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.4%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.4%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses74.8%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity74.8%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified74.8%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 82.6%

      \[\leadsto \color{blue}{x + -2 \cdot \left(wj \cdot x\right)} \]
    6. Step-by-step derivation
      1. *-commutative82.6%

        \[\leadsto x + -2 \cdot \color{blue}{\left(x \cdot wj\right)} \]
    7. Simplified82.6%

      \[\leadsto \color{blue}{x + -2 \cdot \left(x \cdot wj\right)} \]

    if 1.4000000000000001e-7 < wj

    1. Initial program 46.1%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in46.0%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/46.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub46.1%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*46.1%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses96.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity96.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified96.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 75.6%

      \[\leadsto \color{blue}{wj - \frac{wj}{1 + wj}} \]
    6. Step-by-step derivation
      1. +-commutative75.6%

        \[\leadsto wj - \frac{wj}{\color{blue}{wj + 1}} \]
    7. Simplified75.6%

      \[\leadsto \color{blue}{wj - \frac{wj}{wj + 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification82.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 1.4 \cdot 10^{-7}:\\ \;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\ \mathbf{else}:\\ \;\;\;\;wj + \frac{wj}{-1 - wj}\\ \end{array} \]
  5. Add Preprocessing

Alternative 11: 85.4% accurate, 26.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 0.95:\\ \;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\ \mathbf{else}:\\ \;\;\;\;wj + -1\\ \end{array} \end{array} \]
(FPCore (wj x)
 :precision binary64
 (if (<= wj 0.95) (+ x (* -2.0 (* wj x))) (+ wj -1.0)))
double code(double wj, double x) {
	double tmp;
	if (wj <= 0.95) {
		tmp = x + (-2.0 * (wj * x));
	} else {
		tmp = wj + -1.0;
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 0.95d0) then
        tmp = x + ((-2.0d0) * (wj * x))
    else
        tmp = wj + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 0.95) {
		tmp = x + (-2.0 * (wj * x));
	} else {
		tmp = wj + -1.0;
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 0.95:
		tmp = x + (-2.0 * (wj * x))
	else:
		tmp = wj + -1.0
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 0.95)
		tmp = Float64(x + Float64(-2.0 * Float64(wj * x)));
	else
		tmp = Float64(wj + -1.0);
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 0.95)
		tmp = x + (-2.0 * (wj * x));
	else
		tmp = wj + -1.0;
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 0.95], N[(x + N[(-2.0 * N[(wj * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(wj + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 0.95:\\
\;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\

\mathbf{else}:\\
\;\;\;\;wj + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 0.94999999999999996

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 81.4%

      \[\leadsto \color{blue}{x + -2 \cdot \left(wj \cdot x\right)} \]
    6. Step-by-step derivation
      1. *-commutative81.4%

        \[\leadsto x + -2 \cdot \color{blue}{\left(x \cdot wj\right)} \]
    7. Simplified81.4%

      \[\leadsto \color{blue}{x + -2 \cdot \left(x \cdot wj\right)} \]

    if 0.94999999999999996 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around inf 75.2%

      \[\leadsto wj - \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification81.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 0.95:\\ \;\;\;\;x + -2 \cdot \left(wj \cdot x\right)\\ \mathbf{else}:\\ \;\;\;\;wj + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 12: 84.8% accurate, 39.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;wj \leq 1.8:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;wj + -1\\ \end{array} \end{array} \]
(FPCore (wj x) :precision binary64 (if (<= wj 1.8) x (+ wj -1.0)))
double code(double wj, double x) {
	double tmp;
	if (wj <= 1.8) {
		tmp = x;
	} else {
		tmp = wj + -1.0;
	}
	return tmp;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    real(8) :: tmp
    if (wj <= 1.8d0) then
        tmp = x
    else
        tmp = wj + (-1.0d0)
    end if
    code = tmp
end function
public static double code(double wj, double x) {
	double tmp;
	if (wj <= 1.8) {
		tmp = x;
	} else {
		tmp = wj + -1.0;
	}
	return tmp;
}
def code(wj, x):
	tmp = 0
	if wj <= 1.8:
		tmp = x
	else:
		tmp = wj + -1.0
	return tmp
function code(wj, x)
	tmp = 0.0
	if (wj <= 1.8)
		tmp = x;
	else
		tmp = Float64(wj + -1.0);
	end
	return tmp
end
function tmp_2 = code(wj, x)
	tmp = 0.0;
	if (wj <= 1.8)
		tmp = x;
	else
		tmp = wj + -1.0;
	end
	tmp_2 = tmp;
end
code[wj_, x_] := If[LessEqual[wj, 1.8], x, N[(wj + -1.0), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;wj \leq 1.8:\\
\;\;\;\;x\\

\mathbf{else}:\\
\;\;\;\;wj + -1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if wj < 1.80000000000000004

    1. Initial program 74.7%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in75.1%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/75.1%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub74.7%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*74.7%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses75.1%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity75.1%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified75.1%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around 0 80.6%

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

    if 1.80000000000000004 < wj

    1. Initial program 22.2%

      \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
    2. Step-by-step derivation
      1. distribute-rgt1-in22.2%

        \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
      2. associate-/l/22.2%

        \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
      3. div-sub22.2%

        \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
      4. associate-/l*22.2%

        \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
      5. *-inverses100.0%

        \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
      6. *-rgt-identity100.0%

        \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
    4. Add Preprocessing
    5. Taylor expanded in wj around inf 75.2%

      \[\leadsto wj - \color{blue}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification80.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;wj \leq 1.8:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;wj + -1\\ \end{array} \]
  5. Add Preprocessing

Alternative 13: 84.0% accurate, 313.0× speedup?

\[\begin{array}{l} \\ x \end{array} \]
(FPCore (wj x) :precision binary64 x)
double code(double wj, double x) {
	return x;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    code = x
end function
public static double code(double wj, double x) {
	return x;
}
def code(wj, x):
	return x
function code(wj, x)
	return x
end
function tmp = code(wj, x)
	tmp = x;
end
code[wj_, x_] := x
\begin{array}{l}

\\
x
\end{array}
Derivation
  1. Initial program 72.9%

    \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
  2. Step-by-step derivation
    1. distribute-rgt1-in73.2%

      \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
    2. associate-/l/73.2%

      \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
    3. div-sub72.9%

      \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
    4. associate-/l*72.9%

      \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
    5. *-inverses76.0%

      \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
    6. *-rgt-identity76.0%

      \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
  3. Simplified76.0%

    \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
  4. Add Preprocessing
  5. Taylor expanded in wj around 0 77.9%

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

Alternative 14: 4.4% accurate, 313.0× speedup?

\[\begin{array}{l} \\ wj \end{array} \]
(FPCore (wj x) :precision binary64 wj)
double code(double wj, double x) {
	return wj;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    code = wj
end function
public static double code(double wj, double x) {
	return wj;
}
def code(wj, x):
	return wj
function code(wj, x)
	return wj
end
function tmp = code(wj, x)
	tmp = wj;
end
code[wj_, x_] := wj
\begin{array}{l}

\\
wj
\end{array}
Derivation
  1. Initial program 72.9%

    \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
  2. Step-by-step derivation
    1. distribute-rgt1-in73.2%

      \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
    2. associate-/l/73.2%

      \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
    3. div-sub72.9%

      \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
    4. associate-/l*72.9%

      \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
    5. *-inverses76.0%

      \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
    6. *-rgt-identity76.0%

      \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
  3. Simplified76.0%

    \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
  4. Add Preprocessing
  5. Taylor expanded in wj around inf 5.4%

    \[\leadsto \color{blue}{wj} \]
  6. Add Preprocessing

Alternative 15: 3.3% accurate, 313.0× speedup?

\[\begin{array}{l} \\ -1 \end{array} \]
(FPCore (wj x) :precision binary64 -1.0)
double code(double wj, double x) {
	return -1.0;
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    code = -1.0d0
end function
public static double code(double wj, double x) {
	return -1.0;
}
def code(wj, x):
	return -1.0
function code(wj, x)
	return -1.0
end
function tmp = code(wj, x)
	tmp = -1.0;
end
code[wj_, x_] := -1.0
\begin{array}{l}

\\
-1
\end{array}
Derivation
  1. Initial program 72.9%

    \[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}} \]
  2. Step-by-step derivation
    1. distribute-rgt1-in73.2%

      \[\leadsto wj - \frac{wj \cdot e^{wj} - x}{\color{blue}{\left(wj + 1\right) \cdot e^{wj}}} \]
    2. associate-/l/73.2%

      \[\leadsto wj - \color{blue}{\frac{\frac{wj \cdot e^{wj} - x}{e^{wj}}}{wj + 1}} \]
    3. div-sub72.9%

      \[\leadsto wj - \frac{\color{blue}{\frac{wj \cdot e^{wj}}{e^{wj}} - \frac{x}{e^{wj}}}}{wj + 1} \]
    4. associate-/l*72.9%

      \[\leadsto wj - \frac{\color{blue}{wj \cdot \frac{e^{wj}}{e^{wj}}} - \frac{x}{e^{wj}}}{wj + 1} \]
    5. *-inverses76.0%

      \[\leadsto wj - \frac{wj \cdot \color{blue}{1} - \frac{x}{e^{wj}}}{wj + 1} \]
    6. *-rgt-identity76.0%

      \[\leadsto wj - \frac{\color{blue}{wj} - \frac{x}{e^{wj}}}{wj + 1} \]
  3. Simplified76.0%

    \[\leadsto \color{blue}{wj - \frac{wj - \frac{x}{e^{wj}}}{wj + 1}} \]
  4. Add Preprocessing
  5. Taylor expanded in wj around inf 5.9%

    \[\leadsto wj - \color{blue}{1} \]
  6. Taylor expanded in wj around 0 3.2%

    \[\leadsto \color{blue}{-1} \]
  7. Add Preprocessing

Developer Target 1: 79.1% accurate, 1.5× speedup?

\[\begin{array}{l} \\ wj - \left(\frac{wj}{wj + 1} - \frac{x}{e^{wj} + wj \cdot e^{wj}}\right) \end{array} \]
(FPCore (wj x)
 :precision binary64
 (- wj (- (/ wj (+ wj 1.0)) (/ x (+ (exp wj) (* wj (exp wj)))))))
double code(double wj, double x) {
	return wj - ((wj / (wj + 1.0)) - (x / (exp(wj) + (wj * exp(wj)))));
}
real(8) function code(wj, x)
    real(8), intent (in) :: wj
    real(8), intent (in) :: x
    code = wj - ((wj / (wj + 1.0d0)) - (x / (exp(wj) + (wj * exp(wj)))))
end function
public static double code(double wj, double x) {
	return wj - ((wj / (wj + 1.0)) - (x / (Math.exp(wj) + (wj * Math.exp(wj)))));
}
def code(wj, x):
	return wj - ((wj / (wj + 1.0)) - (x / (math.exp(wj) + (wj * math.exp(wj)))))
function code(wj, x)
	return Float64(wj - Float64(Float64(wj / Float64(wj + 1.0)) - Float64(x / Float64(exp(wj) + Float64(wj * exp(wj))))))
end
function tmp = code(wj, x)
	tmp = wj - ((wj / (wj + 1.0)) - (x / (exp(wj) + (wj * exp(wj)))));
end
code[wj_, x_] := N[(wj - N[(N[(wj / N[(wj + 1.0), $MachinePrecision]), $MachinePrecision] - N[(x / N[(N[Exp[wj], $MachinePrecision] + N[(wj * N[Exp[wj], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
wj - \left(\frac{wj}{wj + 1} - \frac{x}{e^{wj} + wj \cdot e^{wj}}\right)
\end{array}

Reproduce

?
herbie shell --seed 2024123 
(FPCore (wj x)
  :name "Jmat.Real.lambertw, newton loop step"
  :precision binary64

  :alt
  (! :herbie-platform default (let ((ew (exp wj))) (- wj (- (/ wj (+ wj 1)) (/ x (+ ew (* wj ew)))))))

  (- wj (/ (- (* wj (exp wj)) x) (+ (exp wj) (* wj (exp wj))))))