[Getfem-users] Question on Preconditioners

[Bwalya Malama]

Hi:

I am trying to solve a system of equations using iterative solver, QMR, in
particular. I have a problem with getting preconditioners. I tried the
following, where C(N2,N2) is the coefficient matrix:

**********************
gmm::row_matrix< gmm::wsvector<complex<double> > > C(N2,N2);
gmm::row_matrix<std::vector<std::complex<double> > > C1(N2,N2);
gmm::copy(C,C1);
gmm::diagonal_precond<gmm::row_matrix<std::vector<std::complex<double> > >
> P(C1);
****************

This did not work owing to the large size of C1(N2,N2). What is
permissible for matrix_type in "gmm::diagonal_precond<matrix_type>? Note
that the I tried the following and it did not work:

gmm::diagonal_precond<gmm::row_matrix<std::vector<std::complex<double> > >
> P(C);

Please help. It appears that matrix_type cannot be:
gmm::row_matrix< gmm::wsvector<complex<double> > >

Sincerely,
-- Bwalya
Bwalya Malama, Ph.D.
Center for Geophysical Research of the Shallow Subsurface
Boise State University
Boise, Idaho
tel: 208-426-2959
email: address@hidden