CR is a data directory which contains examples of the Compressed Row (CR) sparse matrix file format.
The sparse compressed row data structure involves:
The associated CR file format to store this information uses 3 separate files, containing the column, row, and entry information separately. The value of N can be inferred from the maximum value to occur in the column file. The value of M can be inferred from the length of the row file (minus 1), and the value of NZ_NUM from the length of the column or entry files.
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 Harwell Boeing (HB) files, a sparse matrix file format;
LINPLUS, a C++ library which carries out simple manipulations of matrices in a variety of formats, including matrices stored in symmetric, banded, and sparse formats.
CC, a data directory which contains examples of Compressed Column (CC) files, a three-file format for sparse matrices;
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.
The 4 by 6 matrix
11 0 0 14 0 16 0 22 0 0 25 26 0 0 33 34 0 36 41 0 43 44 0 46could be stored as the following CR files: (Here we are using 1-based indices)
ROW:
1 4 7 10 14
COL:
1 (row 1 begins on line 1) 4 6 2 (row 2 begins on line 4) 5 6 3 (row 3 begins on line 7) 4 6 1 (row 4 begins on line 10) 3 4 6 * (row 5 would begin on line 14)
ENTRY:
11.0 (row 1 begins on line 1) 14.0 16.0 22.0 (row 2 begins on line 4) 25.0 26.0 33.0 (row 3 begins on line 7) 34.0 36.0 41.0 (row 4 begins on line 10) 43.0 44.0 46.0 * (row 5 would begin on line 14)
X01 is a simple example for which M=N=5 and NZ_NUM=12.
X02 is related to a finite difference approximation (-1,2-1) of the second derivative at a set of 20 equally spaced points in 1D. Thus M=N=20 and NZ_NUM=58.
X03 is related to a finite difference approximation (-1,-1,4,-1,-1) of the second derivative at a 5 by 5 grid of equally spaced points in 2D. Thus M=N=25 and NZ_NUM=105.
You can go up one level to the DATA page.