The bounds of eigenvalues independent of both degrees of high-order elements and mesh sizes are shown for the preconditioned system by bilinear finite elements for the spectral element discretizations based on Legendre-Gauss-Lobatto points for a coupl...
The bounds of eigenvalues independent of both degrees of high-order elements and mesh sizes are shown for the preconditioned system by bilinear finite elements for the spectral element discretizations based on Legendre-Gauss-Lobatto points for a coupled elliptic operator derived from an optimal control problem. The GMRES methods are used to implement the preconditioned system. It is provided that the convergence factor of GMRES does not depend on the number of elements and degrees of polynomials with numerical evidences. Some numerical demonstrations on the effects of preconditioning are presented with applications to a test optimal control problem.