Hello,
I have so far solved scalar field problems using finite elements on a given
(unstructured) mesh. I made use of MATMPIAIJ to create matrixes,
MatCreateVecs(A, &b, &x) to create vectors, and MatZeroRowsColumnsIS to set
boundary conditions.
Now, I would like to solve a coupled system of equations for the quantities u1
and u2 on the (unstructured) mesh. I.e., the matrix should get the double
number of rows and columns,
A = [A00 A01
A10 A11]
the vectors contain twice the number of entries (e.g. first all u1s and then
all u2s). I would like to be sure that the entries of u1 and u2, which are
associated with the same element are located on the same processor.
Is a pre-defined structure already available within PETSc to enlarge such a
single equation to store the entries of coupled equations?
-\Delta u_1+c_{11} u_1+c_{12} u_2=f_1
-\Delta u_2+c_{21} u_1+c_{22} u_2=f_2
Would I still be able to use MatZeroRowsColumnsIS u1 and u2 independently to
enforce boundary conditions? MatZeroRowsColumnsIS(A, is, 1, x, b);
I don’t know where to begin. I have so far only been exposed to using MATMPIAIJ
and MatSetValues to create and assign values to matrix entries respectively. I
would be grateful if you could provide the stepwise guide.
Kind regards,
Karthik.
--
Karthik Chockalingam, Ph.D.
Senior Research Software Engineer
High Performance Systems Engineering Group
Hartree Centre | Science and Technology Facilities Council
[email protected]<mailto:[email protected]>
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