Hello Matt, Thanks for your reply. I am actually retrying against the latest PETSc and will revert once I get the information.
On Mon, Oct 12, 2015 at 9:39 AM, Matthew Knepley <[email protected]> wrote: > On Sat, Oct 10, 2015 at 7:56 PM, K. N. Ramachandran <[email protected]> > wrote: > >> Sorry, some more questions. >> >> 3) Also, for Dirichlet bc, I specify the value through Identity rows, >> i.e. A_ii = 1 and the rhs value would correspond to the Dirichlet >> condition. I am specifying it this way for my convenience. I am aware that >> MatZerosRowColumns might help here, but would keeping it this way be >> detrimental? >> > > That is fine. However you would want to scale these entries to be > approximately the same size as the other diagonal entries. > > >> 4) Can I expect symmetric matrices to perform better, i.e. if I eliminate >> Dirichlet rows? But I would still be left with Neumann boundary conditions, >> where I use the second order formulation. If I used the first order >> formulation and made it symmetric, would that be an advantage? I tried the >> latter, but I didn't see the condition number change much. >> > > Will not matter for MG. > > Matt > > >> >> Regards, K.N.Ramachandran Ph: 814-441-4279
