[Trilinos-Users] Problem with EpetraExt::MatrixMatrix::Multiply
bender calculon
calculondonbot777 at hotmail.com
Sun Sep 20 04:32:22 MDT 2009
Hi,
I have this problem with EpetraExt:MatrixMatrix::Multiply. I
want to multiply two Epetra_CrsMatrix get from
Trilinos_Util::CrsMatrixGallery.
If I multiply two full matrix ( for
example Hilber Matrix, Cauchy matrix or kms matrix ) or two diagonal
matrix I obtain a correct result, but if I multiply two sparse matrix i
obtain an absurd result.
I explain my problem with a part of my code:
Trilinos_Util::CrsMatrixGallery Problem(problem, Comm); // problem = "laplace_2d"
Problem.Set("problem_size",size); // size = 4
Problem.Set("map_type","linear");
read_A = Problem.GetMatrix(); // Epetra_CrsMatrix *read_A
Num_Glob = read_A->Map().NumGlobalElements(); // int Num_Glob
Epetra_Map Map_func(Num_Glob,0,Comm);
Epetra_Export exporter(read_A -> Map(), Map_func); // I want to export data from *read_A to matrix_A
Epetra_CrsMatrix Matrix_A(Copy, Map_func, 0);
Matrix_A.Export(*read_A,exporter, Zero);
Matrix_A.FillComplete();
cout << Matrix_A;
Epetra_CrsMatrix Matrix_C(Matrix_A); // copy of Matrix_A;
Matrix_C.PutScalar(0);
Matrix_C.FillComplete();
EpetraExt::MatrixMatrix::Multiply(Matrix_A,false,Matrix_A,false,Matrix_C);
// This operation make Matrix_C = Matrix_A*Matrix_A +C not C = A*A
If i put problem = "laplace_2d" and "problem_size" = 4 I obtain this result:
./ex2.exe -problem laplace_2d -size 4
Epetra::CrsMatrix
Number of Global Rows = 4
Number of Global Cols = 4
Number of Global Diagonals = 4
Number of Global Nonzeros = 12
Global Maximum Num Entries = 3
Number of My Rows = 4
Number of My Cols = 4
Number of My Diagonals = 4
Number of My Nonzeros = 12
My Maximum Num Entries = 3
Processor Row Index Col Index Value
0 0 0 17
0 0 1 -8
0 0 2 -4
0 1 0 0
0 1 1 0
0 1 3 0
0 2 0 0
0 2 2 0
0 2 3 0
0 3 1 0
0 3 2 0
0 3 3 0
and you can see that is not correct.
I have trilinos release 9.0.
T
Best regards
Maurizio
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