[petsc-users] Problem with fortran version of ex29 in ksp

[TAY wee-beng]

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
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