Question #108259 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/108259
Anders Logg posted a new comment: On Thu, Apr 29, 2010 at 04:14:21PM -0000, Murtazo Nazarov wrote: > Question #108259 on DOLFIN changed: > https://answers.launchpad.net/dolfin/+question/108259 > > Status: Answered => Solved > > Murtazo Nazarov confirmed that the question is solved: > Yes, it seems hypre in my solver does not converge only in the first > iteration. Before it was just a warning, but with the latest dolfin it > stoped since it is assumed that it is an error. > > Here I made a test for the same problem using the following lines: > > solver = KrylovSolver("gmres") > solver.parameters["monitor_convergence"] = True > solver.parameters["error_on_nonconvergence"] = False > .. > > "Old" dolfin gives: > .... > Applying boundary conditions to linear system. > Applying boundary conditions to linear system. > Solving linear system of size 4184 x 4184 (PETSc Krylov solver). > 0 KSP preconditioned resid norm 2.663347782311e+02 true resid norm > 1.371810197831e+01 ||Ae||/||Ax|| 7.817835153984e+08 > *** Warning: Krylov solver did not converge (PETSc reason -4). > PETSc Krylov solver (gmres, hypre) failed to converge in 0 iterations. > ... > > and the latest dolfin gives: > > Applying boundary conditions to linear system. > Applying boundary conditions to linear system. > Solving linear system of size 4184 x 4184 (PETSc Krylov solver). > 0 KSP preconditioned resid norm 6.346755394553e+02 true resid norm > 3.269022479529e+01 ||Ae||/||Ax|| 3.675021072956e+08 > *** Warning: Krylov solver did not converge (PETSc reason -4). > PETSc Krylov solver (gmres, hypre) failed to converge in 0 iterations. > > It happened because of the luck of stabilization in startup. > > It is nice to know about the latest flags in the parameter list for the > Krylov solver. > > murtazo ok, good to know. So there is nothing wrong with the solver. I suggest you let "error_on_nonconvergence" stay true, otherwise you will not see when it fails. -- Anders -- You received this question notification because you are a member of DOLFIN Team, which is an answer contact for DOLFIN. _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
