**Delta factor**- This is used to determine the delta value for the finite difference numerical differentiation. The delta is calculated as the product of the delta factor and the current absolute value of the variable. If the resulting value is smaller than the "Delta minimum" parameter, it is discarded and the "Delta minimum" value is used instead. Default value is $10^{-6}$

**Delta minimum**- The minimal delta for numerical differentiation. Default value is $10^{-12}$.