[petsc-users] create a sparse symmetric matrix

[Yifei Li]

Hi all,

I only filled the entries in the upper triangular part of the matrix,
however, I got  0 when I tried to get the value of some entry in the lower
triangular part.

Here's how I do it:


MatCreate(PETSC_COMM_WORLD, &A);

MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, n, n);

MatSetType(A, MATSEQSBAIJ);

MatSetUp(A);

// I set the value for the entry at (0, 2)

int i = 2, j = 0;

MatGetValues(A,1,&i,1,&j,values);



Any help is highly appreicated.



Yifei
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