[petsc-users] Insert values into matrix using MatSetValuesStencil

[TAY wee-beng]

Hi,

I have successfully used MatSetValuesStencil to insert values into a 
Poisson eqn matrix which has 1 DOF (pressure). Now I'm trying to insert 
values in a momentum eqn matrix which has 3 DOF (u,v,w)

However, I got the error:

/*[0]PETSC ERROR: --------------------- Error Message 
----------------------------*//*
*//*----------------------------------*//*
*//*[0]PETSC ERROR: Argument out of range*//*
*//*[0]PETSC ERROR: Inserting a new nonzero at (111,5) in the matrix*//*
*//*[0]PETSC ERROR: See 
http://www.mcs.anl.gov/petsc/documentation/faq.html for trou*//*
*//*ble shooting.*/

I wonder what's wrong.  For the momentum eqn, for each DOF, at at node 
(dof,i,j,k), I have coupling i +/- 1, j +/- 1 and k +/- 1.

The error happens at 111,5, which corresponds to i = 2, j = 2, k = 2, 
which is an internal node.

Here's part of my code below. Hope someone can help. Thanks!
*/
/**/PetscScalar :: value_insert(7)/**/
/**/
/**/MatStencil  :: row(6,1),col(6,7)/**/
/**/
/**/ione = 1;   iseven = 7/**/
/**/
/**/if (cell_type == 'u') then/**/
/**/
/**/    offset = 1/**/
/**//**/
/**/else if (cell_type == 'v') then/**/
/**/
/**/    offset = 2/**/
/**//**/
/**/else if (cell_type == 'w') then/**/
/**/
/**/    offset = 3/**/
/**//**/
/**/end if/**/
/**/
/**/do k=ksta2,kend2/**/
/**/
/**/    do j = jsta2,jend2/**/
/**/
/**/        do i=2,size_x-1/**/
/**//**/
/**/            row(MatStencil_i,1) = i - 1/**/
/**//**/
/**/            row(MatStencil_j,1) = j - 1/**/
/**//**/
/**/            row(MatStencil_k,1) = k - 1/**/
/**//**/
/**/            row(MatStencil_c,1) = offset - 1/**/
/**//**/
/**/            value_insert = 0.d0/**/
/**//**/
/**/            col(MatStencil_i,3) = i + 1 - 1 !east/**/
/**//**/
/**/            col(MatStencil_j,3) = j - 1/**/
/**//**/
/**/            col(MatStencil_k,3) = k - 1/**/
/**//**/
/**/            col(MatStencil_c,3) = offset - 1/**/
/**//**/
/**/            value_insert(3) = -( 
1./(cell_x(i)%pd_E+cell_x(i+1)%pd_W))*(c_yz(j,k)%fc_E)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,5) = i - 1 - 1 !west/**/
/**//**/
/**/            col(MatStencil_j,5) = j - 1/**/
/**//**/
/**/            col(MatStencil_k,5) = k - 1/**/
/**//**/
/**/            col(MatStencil_c,5) = offset - 1/**/
/**//**/
/**/            value_insert(5) = -( 
1./(cell_x(i)%pd_W+cell_x(i-1)%pd_E))*(c_yz(j,k)%fc_E)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,2) = i - 1 !north/**/
/**//**/
/**/            col(MatStencil_j,2) = j + 1 - 1/**/
/**//**/
/**/            col(MatStencil_k,2) = k - 1/**/
/**//**/
/**/            col(MatStencil_c,2) = offset - 1/**/
/**//**/
/**/            value_insert(2) = -( 
1./(cell_y(j)%pd_N+cell_y(j+1)%pd_S))*(c_zx(i,k)%fc_N)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,4) = i - 1 !south/**/
/**//**/
/**/            col(MatStencil_j,4) = j - 1 - 1/**/
/**//**/
/**/            col(MatStencil_k,4) = k - 1/**/
/**//**/
/**/            col(MatStencil_c,4) = offset - 1/**/
/**//**/
/**/            value_insert(4) = -( 
1./(cell_y(j)%pd_S+cell_y(j-1)%pd_N))*(c_zx(i,k)%fc_N)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,6) = i - 1 !front/**/
/**//**/
/**/            col(MatStencil_j,6) = j - 1/**/
/**//**/
/**/            col(MatStencil_k,6) = k + 1 - 1/**/
/**//**/
/**/            col(MatStencil_c,6) = offset - 1/**/
/**//**/
/**/            value_insert(6) = -( 
1./(cell_z(k)%pd_F+cell_z(k+1)%pd_B))*(c_xy(i,j)%fc_F)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,7) = i - 1 !back/**/
/**//**/
/**/            col(MatStencil_j,7) = j - 1/**/
/**//**/
/**/            col(MatStencil_k,7) = k - 1 - 1/**/
/**//**/
/**/            col(MatStencil_c,7) = offset - 1/**/
/**//**/
/**/            value_insert(7) = -( 
1./(cell_z(k)%pd_B+cell_z(k-1)%pd_F))*(c_xy(i,j)%fc_F)*inv_Re/**/
/**//**/
/**/            col(MatStencil_i,1) = i - 1/**/
/**//**/
/**/            col(MatStencil_j,1) = j - 1/**/
/**//**/
/**/            col(MatStencil_k,1) = k - 1/**/
/**//**/
/**/            col(MatStencil_c,1) = offset - 1/**/
/**//**/
/**/            value_insert(1) = 2.*c(i,j,k)%vol/del_t - 
(value_insert(2)+value_insert(3)+value_insert(4)+value_insert(5)+value_insert(6)+value_insert(7))/**/
/**//**/
/**/            call 
MatSetValuesStencil(A_semi_xyz,ione,row,iseven,col,value_insert,INSERT_VALUES,ierr)/**/
/**//**/
/**/        end do/**/
/**//**/
/**/    end do/**/
/**/
/**/end do /*

Thank you

Yours sincerely,

TAY wee-beng


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