SPARSE_ELLPACK is a data directory which contains examples of the sparse ELLPACK format, a pair of arrays for storing information about a sparse matrix.
The sparse compressed row data structure involves:
The associated SPARSE_ELLPACK file format to store this information uses 2 separate files, containing the "A" and "J" arrays, one row per line.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
DLAP, a data directory which contains examples of DLAP files, a sparse matrix file format used by the DLAP package;
DSP, a data directory which contains examples of DSP files, a sparse matrix file format, storing just (I,J,A(I,J)), and using one-based indexing.
HB, a data directory which contains examples of HB files, the Harwell Boeing sparse matrix file format;
LINPLUS, a C++ library which carries out simple manipulations of matrices in a variety of formats.
SPARSE, MATLAB programs which illustrate the use of MATLAB's SPARSE matrix utilities;
SPARSE_CC, a data directory which contains examples of SPARSE CC files, a three-file format for the sparse compressed column matrix format;
SPARSE_CR, a data directory which contains examples of SPARSE CR files, a three-file format for the sparse compressed row matrix format;
SPARSEKIT, a FORTRAN90 library which implements operations on sparse matrices, including conversion between various formats, by Yousef Saad.
ST, a data directory which contains examples of ST files, the Sparse Triplet format, a sparse matrix file format, storing just (I,J,A(I,J)), and using zero-based indexing.
Suppose the original matrix is:
11 0 13 0 0 0 21 22 0 24 0 0 0 32 33 0 35 0 0 0 43 44 0 46 51 0 0 54 55 0 61 62 0 0 65 66
Then the sparse ELLPACK format would be:
--------A------- ------J------- 11 13 0 0 1 3 * * 22 21 24 0 2 1 4 * 33 32 35 0 3 2 5 * 44 43 46 0 4 3 6 * 55 51 54 0 5 1 4 * 66 61 62 65 6 1 2 5where the "*" entries in J are arbitrary (but should be between 1 and 6) since the corresponding values of A are 0.
SIX is a simple example for which M=N=6 and J_MAX = 4.
You can go up one level to the DATA page.