This function computes each element of the matrix function DD_weight_2 which is the second derivative of the Ds-optimality criterion with respect to the model parameters.
dd11(T, x1, x2, xl, inv, inv1, order)A numeric vector. Model parameter values
A numeric. ith dose level for a given design
A numeric. jth dose level for a given design
A numeric. last dose level for a given design
A numeric matrix. Inverse of the information matrix for the 5PL model
A numeric matrix. Inverse of the information matrix for the 4PL model
numeric. The number of model paraemters