On Sat, Mar 31, 2012 at 20:03, Barry Smith <bsmith@mcs.anl.gov> wrote:

For non-blocked matrices you can call MatSetBlockSize() anytime (as with vectors changing the blocksize later will also change the block size of any other vectors/matrices that share the layout) , for blocked matrices you CANNOT ever call MatSetBlockSize() and must set it with the appropriate preallocation routine.

Not quite. You can set the block size for BAIJ, but it just checks that it matches the block size used for preallocation and errors if not.