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?
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 > <mailto: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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120502/9011a365/attachment.htm>
