Transformation of the graph G k+1 into the graph G k (a) Example of coloring of a triangular mesh (b) The triangular mesh after deleting certain couplings (c) The triangular mesh after adding certain couplings (d) The new triangular mesh 

Contexts in source publication

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... us consider the matrix A (k+1) , which corresponding a triangular finite element mesh on that level. First step (Partitioning the set of vertices X k+1 ): Color the nodes of the graph in three colors as in Section 2.2: red(•), green(•) and blue( ) (Fig.2(a)). ...

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... step (Approximation of the block A (k) 11 ): Delete all couplings between red and blue nodes by diagonal compensation as in Section 2.2 ( Fig.2(b)). ...

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... ): Add new couplings between green nodes, which occurs during Gaussian elimination of all red and blue nodes, by the diagonal compen- sation (Fig.2(c)). (This is a main point where the present method differs from the method in [6]). ...

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... step (Calculation of the new matrix A (k) ): Eliminate all red and blue nodes. It leads to a new triangular finite element mesh for green points (Fig.2(d)). ...