In addition to the problem data and the nonlinear element types described in Section 3 and 4, the user might also wish to specify the nontrivial group functions, and their derivatives, in a systematic way. A particular nontrivial group function is defined in terms of its group type and variable; both of these quantities are specified in Section 3. Thus, the only details which remain to be specified are the function and derivative values of the group types.
Once again, we present an approach to this issue. As before, data is specified in a file. The file comprises an ordered mixture of indicator and data cards; the latter allow function and derivative definitions in appropriate high-level language statements.