Is there a robust way to implement the following? Suppose I have a block diagonal matrix P = [A 0; 0 Q]; and I know the indices of A and Q in this block matrix. I now want to apply different preconditioners on the A block and on the Q block.
One way, that I've had some success with, is to write a PCSHELL, where I split the input and output vectors using index sets and apply the relevant preconditioner on each of these. However, this hardwires things, and I was wondering if there was another method. -gideon -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20080107/2c6f3695/attachment.htm>
