This function transforms the copula parameter theta such that theta2z(theta) is unrestricted.
Usage
theta2z(theta, family)
Arguments
theta
copula parameter
family
an integer defining the bivariate copula family: 1 = Gauss, 3 = Clayton, 4=Gumbel, 5=Frank
Value
transformation
Details
This function transforms the parameter of a copula such that the transformed value in unconstrained. E.g., for the Gauss copula (family=1), the parameter $\theta$ lies in the interval $]-1,1[$, and the transformation is defined as
$$\theta \mapsto\frac{1}{2} \ln \left(\frac{1+\theta}{1-\theta}\right)$$