Hi, I need to solve M*x=f, where matrix M consists of 4 blocks: [ A B; C D ]
I already have old code to build petsc sparse matrices A, B, C and D and the RHS vectors f1 and f2 (such that f=[f1; f2]), each having global indices starting from 0. My question is: is there already API(s) that I can easily assemble matrices A,B,C and D into M? Or do I have to build M from scratch? Thanks, Shao-Ching
