Hello,
In my code I have
call KSPSetComputeOperators(ksp_u, compute_matrix_u,
PETSC_NULL_OBJECT, ierr)
later I have something like
call KSPSolve(ksp_u, RHS_u_vec, u3_vec, ierr)
call DMCreateMatrix(da_u, B, ierr)
call compute_matrix_u(ksp_u, B, B, PETSC_NULL_INTEGER, ierr)
call KSPGetOperators(ksp_u, A, PETSC_NULL_OBJECT, ierr)
call MatEqual(A, B, flg, ierr)
inside a loop.
On the first iteration 'flg' is set to PETSC_TRUE but after that it is
set to PETSC_FALSE. Why is that?
My code includes a hand-crafted iterative solver and I want to be able
to evaluate the residual norm of the aproximate solution it produces
using the matrix of an analogous PETSc solver. I am trying to determine
the best way to obtain this matrix. In this case KSPSolve will not have
been called and I want to know if I can obtain it using compute_matrix_u.
David
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