In this paper,the operator is evaluated with energy norm for the non-symmetric and indefinite elliptic problem without regularity assumption,then the convergence of multigrid algorithm is proved based on the Richardson iteration and two base assumptions.

Richardson iterative method for solving system of linear equations with the positive definite coefficient matrix is considered,and a new constant step length rule only depending on the minimal diagonal element and the maximum eigenvalue is proposed.

Restoration of pinhole images using Lucy-Richardson algorithm;