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5.1.1 The Values and Derivatives Required

It is assumed that a nonlinear group type i
s specified in terms of its
group-type variable
as described on a `GROUP TYPE`
data card in an SDIF file, see Section 3.2.17. An optimization
procedure is likely to require the values of the group functions
and their first and second derivatives
(taken with respect to the
variable). We now describe how to set up the data for a given
problem.