The substitution-iteration process illustrated in §11.1 is available as an option in find_global_min. The process is enabled by setting the logical variable USE_SUBSIT in configuration file OPTTBND.CFG to "T". Unpublished experimentation has indicated that it is usually beneficial to enable substitution-iteration for global optimization. However, this is not true for all problems, and the user may profit from some experimentation.
The situation is more complex for root-finding. In particular, simple substitution-iteration using the entire code list is usually not beneficial in this context. However, the user can sometimes define specific auxiliary operations that help. This option is available in find_roots, but has not been extensively tested. The flag USE_SUBSIT in configuration file ROOTSDL.CFG should normally be set to "F", but may be set to ``T" if the user has provided a set of relations for substitution-iteration. The set of relations is provided in the routine USER_COMPONENT_SOLVE. An example of this routine (for a particular set of relations) occurs in the file function/miscellaneous/usrcmpsol.f90. At present, to install a particular user-defined set of relations, this file needs to be changed, and GlobSol needs to be rebuilt. (The subroutines called in usrcmpsol.f90 are found in the module CHECK_AND_EXTENDED in file overload/checkx.f90.)