The results reported in this section have been obtained by using
the implementation DIRCOL (cf. [17])
of the direct collocation method mentioned in the previous sections.
The use of grid refinement techniques yields a sequence of related
nonlinear programs with increasing dimensions. In each macro iteration step,
one nonlinear program
has to be solved by the Sequential Quadratic Programming method NPSOL
due to Gill, Murray, Saunders, and Wright [10].
The reported estimates of adjoint variables are direct outputs of DIRCOL.