Shape-based computations on regular processor networks

Spatial structures are particularly suited to the definition of parallel programs, due to their homogeneity. The Movie-based Programming Framework allows specification of computations on regular networks of processors, and the visualization of the computation progress as processors are activated. Computations over spatial structures are specified by composing independent views on propagation of control flows and formulae defining local computations. A shape pattern indicates which processors have to be active during a specific phase of the computation. A visit pattern defines the law of propagation for actual processor activation. By combining these types of patterns, we achieve sophisticated forms of specification. In particular, one specifies visitors implementing collective communication schemas widely used in parallel programming: broadcast, gather, scatter and reduction. As a result, automatic generation of visit algorithms adapted to different network configurations is made possible, thus facilitating experimentation with different laws and their visualization.