 over
the basis function indices.  Since the computation is a quartic
function of the block size while the communication is only a quadratic
function, the block size may be adjusted to ensure the computation time
dominates the communication time.

 <P> We <I>previously</I> stripmined by grouping basis functions
according to their (usually atomic) centers.  This had the advantage
that the geometrical sparsity may be exploited in the outer
stripmining loops.  However, the granularity was fixed and was
inadequ