On Wed, May 2, 2012 at 1:55 PM, TAY wee-beng <zonexo at gmail.com> wrote:
> Hi, > > I did a MatView and VecView on both C and Fortran, right after Mat and Vec > assembly. I have attached the printout below. They are exactly the same, > but yet the result is different in Neumann condition. However, the > dirichlet condition gives the correct ans. Is there anything else that > could be wrong even if the Mat and Vec are the same? > Did you set the null space for the matrix when you have Neumann conditions? Matt > Thanks! > > Fortran: > > Matrix Object: 1 MPI processes > type: seqaij > row 0: (0, 2) (1, -1) (3, -1) > row 1: (0, -1) (1, 3) (2, -1) (4, -1) > row 2: (1, -1) (2, 2) (5, -1) > row 3: (0, -1) (3, 3) (4, -1) (6, -1) > row 4: (1, -1) (3, -1) (4, 4) (5, -1) (7, -1) > row 5: (2, -1) (4, -1) (5, 3) (8, -1) > row 6: (3, -1) (6, 2) (7, -1) > row 7: (4, -1) (6, -1) (7, 3) (8, -1) > row 8: (5, -1) (7, -1) (8, 2) > Vector Object:Vec_0000000084000000_0 1 MPI processes > type: mpi > Process [0] > 0.25 > 0.0205213 > 1.135e-005 > 0.0205213 > 0.00168449 > 9.31663e-007 > 1.135e-005 > 9.31663e-007 > 5.15289e-010 > Vector Object:Vec_0000000084000000_1 1 MPI processes > type: mpi > Process [0] > 0.14924 > 0.0242397 > -0.0260347 > 0.0242397 > -0.0256192 > -0.0400102 > -0.0260347 > -0.0400102 > -0.0400102 > Press any key to continue . . . > > C: > > Matrix Object: 1 MPI processes > type: seqaij > row 0: (0, 2) (1, -1) (3, -1) > row 1: (0, -1) (1, 3) (2, -1) (4, -1) > row 2: (1, -1) (2, 2) (5, -1) > row 3: (0, -1) (3, 3) (4, -1) (6, -1) > row 4: (1, -1) (3, -1) (4, 4) (5, -1) (7, -1) > row 5: (2, -1) (4, -1) (5, 3) (8, -1) > row 6: (3, -1) (6, 2) (7, -1) > row 7: (4, -1) (6, -1) (7, 3) (8, -1) > row 8: (5, -1) (7, -1) (8, 2) > Vector Object:Vec_0x1d3b000_0 1 MPI processes > type: mpi > Process [0] > 0.25 > 0.0205212 > 1.135e-05 > 0.0205212 > 0.00168449 > 9.31663e-07 > 1.135e-05 > 9.31663e-07 > 5.15288e-10 > Vector Object:Vec_0x1d3b000_1 1 MPI processes > type: mpi > Process [0] > 0.139311 > 0.0305751 > -0.0220633 > 0.0305751 > -0.0135158 > -0.042185 > -0.0220633 > -0.042185 > -0.058449 > > > > Yours sincerely, > > TAY wee-beng > > > On 1/5/2012 11:54 PM, Matthew Knepley wrote: > > On Tue, May 1, 2012 at 5:48 PM, TAY wee-beng <zonexo at gmail.com> wrote: > >> Hi, >> >> Do you mean my method is wrong? >> >> I am following the template of ex22f, >> >> where the variables are declared as : >> >> PetscScalar v(5) >> >> MatStencil row(4),col(4,5) >> >> Hence, >> >> for the neumann BC >> >> num = 1 >> >> if (j/=0) then >> >> v(num) = -rho*HxdHy >> >> col(MatStencil_i,num) = i >> >> col(MatStencil_j,num) = j-1 >> >> num = num + 1 >> >> end if >> >> if (i/=0) then >> >> v(num) = -rho*HydHx >> >> col(MatStencil_i,num) = i-1 >> >> col(MatStencil_j,num) = j >> >> num = num + 1 >> >> end if >> >> if (i/=mx-1) then >> >> v(num) = -rho*HydHx >> >> col(MatStencil_i,num) = i+1 >> >> col(MatStencil_j,num) = j >> >> num = num + 1 >> >> end if >> >> if (j/=my-1) then >> >> v(num) = -rho*HxdHy >> >> col(MatStencil_i,num) = i >> >> col(MatStencil_j,num) = j+1 >> >> num = num + 1 >> >> end if >> >> v(num) = ((num-1)/2.0)*rho*(HxdHy + HydHx) >> >> print *, v >> >> col(MatStencil_i,num) = i >> >> col(MatStencil_j,num) = j >> >> !num = num + 1 >> >> call >> MatSetValuesStencil(jac,i1,row,num,col,v,INSERT_VALUES,ierr) >> >> I do not get any more out of range error. However,my ans is still >> different from that of ex29 in C. >> > > This is very simple. You have an error in your code. Checking it is very > simple: run the code and > break in MatSetValues(). Make sure ex29 makes calls with exactly the same > indices as your ex29f. > > Matt > > >> Yours sincerely, >> >> TAY wee-beng >> > > -- > 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 > > -- 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120502/4f7a1ff0/attachment-0001.htm>
