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ArrayToSparse


Unit:SDL_matrix
Class: TIntMatrix
Declaration: procedure ArrayToSparse (AllocBy: longint);

The method ArrayToSparse converts a normal full array-based representation of the matrix into a sparse matrix. Please note that this conversion is only meaningful for matrices which contain at least 70 % zeroes. Sparse matrices are in general more memory efficient if the matrix contains a high percentage of zeroes, however access to a sparse matrix is much slower.

The parameter AllocBy specifies the number of elements for which memory is allocated in advance. AllocBy should be set approx. 10 % higher than the expected number of non-zero elements in order to ensure maximum performance. The minimum amount of memory required by a sparse matrix is given by 12*AllocBy for TIntMatrix, or 16*AllocBy for TMatrix



Last Update: 2012-Okt-20