P6

Long Chen and Chensong Zhang. A coarsening algorithm and multilevel methods on adaptive grids by newest vertex bisection.

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ABSTRACT:
In this paper, a new coarsening algorithm is proposed for the adaptive grids obtained by the newest vertex bisection method in two dimensions. One distinguish feature of our approach is that we do not maintain the refinement tree. A new hierarchical basis preconditioner for second order elliptic equations is developed based on the nested grids obtained by the coarsening algorithm. Numerical experiments shows that the proposed coarsening algorithm and preconditioner are very efficient and easy to implement.