On Sun, 28 Sep 2008, Manav Bhatia wrote:
> Hi, > > I have a few questions about the block format matrix. > > In the function: MatCreateSeqBAIJ, the arguments are > > bs - size of block > m - number of rows > n - number of columns > nz - number of nonzero blocks per block row (same for all rows) > nnz - array containing the number of nonzero blocks in the various block > rows (possibly different for each block row) or PETSC_NULL > > If I specify the nnz vector, then what is the dimension of this vector? Is > that equal to the block size? If so, then is it assumed that all blocks have > the same number of non-zeros per row? Treating each block of BAIJ matrix as a single entry in AIJ format, nnz is an array of size N/bs. > > If my blocks have different non-zero patterns, then should I use an AIJ > format instead of a BAIJ format? You should use AIJ format. See http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#blocks. Hong > > Thanks, > Manav
