Hi, I have two linear systems:
A1*x1=b1 A2*x2=b2 Each of A1 and A2 has a null space with a constant vector (like [1 1 ... 1]') in it, so I currently use MatNullSpaceCreate(with n=0,has_cnst=PETSC_TRUE). Now I want to solve these two systems in one solve, i.e. A*x = b where A = [A1 0; 0 A2] and x=[x1 x2]', b=[b1 b2]' Can I just put two vectors [1 1 1 ... 1 0 0 ... 0]' (i.e. null space from A1) [0 0 0 ... 0 1 1 ... 1]' (i.e. null space from A2) into MatNullSpaceCreate (with n=2,has_cnst=PETSC_FALSE) to span the null space? Thanks. Shao-Ching
