Table 2.

Common estimator functions G for a neg-entropy approximation.

No.	Function
1	$\mathit{G}(u)=\frac{1}{a_1}\text{log cosh} a_{1}u \text{for} 0\le a_1\le 1$
2	$\mathit{G}(u)=-e^{\frac{-u^2}{2}}$
3	G(u) = u3