General description

This is the main part of the whole software package. It performs Metropolis Monte-Carlo sampling of the system described by a trial set of potentials, then compares sampled distribution functions with the reference ones, and introduces a correction to the set of potentials. Then the new iteration starts, now with the corrected set of potentials. The process of inversion of RDFs can be regarded as completed when agreement between sampled and reference distribution functions is reached.

The software automatically analyses the provided input files: molecular descriptions, RDFs and/or potentials files and checks them for consistency. If potentials for some interactions are not provided, they will be deduced from the corresponding RDFs. By default a zero-potential (except the core with zero reference RDF) is used as a starting potential for all non-bonded interactions, and potential of mean force is used for the bonding interactions (pairwise and angular). It is also possible to use potential of mean force as a starting potential for non-bonded interactions (not always suitable for multisite coarse-grained molecules). A user can choose the kind of trial potentials for every interaction in the .rdf file using keywords [InitZero]&InitZero, &InitPMF. If for some interactions only potential is provided, but the corresponding RDF is missing, this potential will be used for sampling, but excluded from the inverse procedure (i.e. kept fixed). If neither potentials nor RDFs are provided for certain non-bonded interaction, then such interaction will not be used in the MC simulation (which is equivalent that corresponding interaction potential is set to zero). In case if RDF-file is absent, no inverse procedure will be performed and the program will just run a standard MC simulation with the supplied potential. In addition it is also possible to explicitly fix some potentials and do not update them in the inverse procedure using keyword [InitZero]&Fixed in the potential file. Other potentials (without keyword &Fixed) will be either fit to the corresponding RDFs (standard IMC mode), or the the whole RDF set if variational IMC mode is used.