Blocking Techniques in Numerical Software

Wilfried N. Gansterer, Dieter F. Kvasnicka, Christoph W. Ueberhuber

Abstract: When developing high performance algorithms blocking is a standard procedure to increase the locality of reference. Conflicting factors which influence the choice of blocking parameters are described in this paper. These factors include cache size, load balancing, memory overhead, algorithmic issues, and others. Optimal block sizes can be determined with respect to each of these factors. The resulting block sizes are independent of each other and can be implemented in several levels of blocking within a program. A tridiagonalization algorithm serves as an example to illustrate various blocking techniques.