On Thu, Apr 3, 2014 at 8:43 AM, Åsmund Ervik <[email protected]> wrote:
> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Dear PETSc users, > > I'm trying to write a Poisson solver in Fortran using the > KSPSetComputeOperators etc. framework. When debugging this, I ended up > modifying ksp/ex22.f so that it matches ksp/ex34.c. The difference > between these is that ex34.c has a non-constant RHS and Neumann BCs, > which is closer to what I want. > If it has Neumann conditions, then it has a null space. Have you included this in your solver? That can cause a residual offset. Matt > Now, when I run these two programs I get the following: > > ./ex22f_mod > Residual, L2 norm 1.007312 > Error, sup norm 0.020941 > Error, L1 norm 10.687882 > Error, L2 norm 0.340425 > > ./ex34 > Residual, L2 norm 1.07124e-05 > Error, sup norm 0.0209405 > Error, L1 norm 0.00618512 > Error, L2 norm 0.000197005 > > but when I MatView/VecView the matrix and RHS for each example (write > them to file), there is no difference. I have attached ex22f_mod.F90, > any suggestions on what the error is? > > Once this example works, you can of course include it with PETSc. > > Regards, > Åsmund > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2.0.22 (GNU/Linux) > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQEcBAEBAgAGBQJTPWWZAAoJED+FDAHgGz19aNYIANyq9k3a5kHzTlAdybkZCYDw > yKtDE5l/4iWYmNL49FH8AocHVcRivLaeJG5CGKqySFtZUXOlC9DM7rn4UmuQecni > dgIQuTk0Ym+OJccHyT5xxnebpFVNrIOTpInfQaDW6dTyeL1svAMeHqslKaGepySL > q/cODbgNDYgl6uumB+POMZevtlM6HPhl/1m7HofcHC9upvTRjSPqP1cg+kg+/8m2 > Fdie/X7PCBfShrAys94kNXNcwtbO7taauphkQGMfyl0gUd+lFATG6zrEZdDqSFlV > c44GFFbxW/SRIDBXdOeX9/cy75KW5do1Sildwb6R4H/i7t6/hCJUJuss7FHjmLc= > =tV3N > -----END PGP SIGNATURE----- > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
