A function which calculates the Jacobian matrix for a given
transformation function subdiagonal_mean_ratio_cor or
subdiagonal_mean_ratio_fct
Jacobian(X, a, d, p, fun)the Jacobian matrix applied for the given vector
vectorized covariance matrix for which the Jacobian matrix is applied
vector containing the indices which belong to the diagonal of the covariance matrix
dimension of the covariance matrix
dimension of the vectorized matrix
transformation function, that should be used.
subdiagonal_mean_ratio_fct or
subdiagonal_mean_ratio_cor