dd11 function

Computing each element of the function DD_weight_2

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)

Arguments

• T: A numeric vector. Model parameter values
• x1: A numeric. ith dose level for a given design
• x2: A numeric. jth dose level for a given design
• xl: A numeric. last dose level for a given design
• inv: A numeric matrix. Inverse of the information matrix for the 5PL model
• inv1: A numeric matrix. Inverse of the information matrix for the 4PL model
• order: numeric. The number of model paraemters