The Multicomputer Toolbox approach to concurrent BLAS and LACS

The authors describe many of the issues involved in general-purpose concurrent basic linear algebra subprograms (concurrent BLAS or CBLAS) and discuss data-distribution independence, while further generalizing data distributions. They comment on the utility of linear algebra communication subprograms (LACS). They also describe an algorithm for dense matrix-matrix multiplication and also discuss matrix-vector multiplication issues. With regard to communication, they conclude that there is limited leverage in LACS per se as a stand-alone message-passing standard, and propose that needed capabilities instead be integrated in a general, application-level message passing standard, focusing attention on CBLAS and large-scale application needs. Most of the proposed LACS features are similar to existing or needed general-purpose primitives anyway. All of the ideas discussed have been implemented or are under current development within the Multicomputer Toolbox open software system