Computational Frameworks enabling multi-scale multi-physics models

In computational models, there is an increasing need for coupling: ranging from coupling at the equation level, to tensor-level coupling and field coupling. Coupling can occur either on model boundaries, or throughout the model. Traditionally, such coupling has been done on an ad-hoc basis, and coupling of traditional computational codes can be so difficult as to require almost complete rewriting of the codes to facilitate coupling. The computational codes we have developed for ACCESS and CIG, such as Snac and Snark, were developed with coupling in mind, and as we have evolved these codes, the support for coupling has gradually improved and become both simpler and yet more powerful. This paper will present our experiences in coupling models and equations within the StGermain Framework, and the lessons we have learned from implementing such coupling