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Sun S3L 3.0 Programming and Reference Guide

S3L_SPARSE_COO - Coordinate Format

S3L_SPARSE_COO files consist of three sections, which are illustrated below and described immediately after.

% <comments>
%
%
m       n       nnz
i1      j1      a(i1, j1)
i1      j1      a(i1, j1)
i1      j1      a(i1, j1)
i1      j1      a(i1, j1)
    :       :       :
innz    jnnz    a(innz, jnnz)

The first section can be used for comments. It consists of one or more lines, each of which begins with the percent "%" character.

The second section consists of a single line containing three integers, shown above as m, n, and nnz. m and n indicate the number of rows and columns of the matrix, respectively, and nnz indicates the total number of nonzero values in the matrix.

The third section lists all nonzero values in the matrix, one value per line. The first two entries on a line are the row and column indices for that value and the third entry is the value itself.

Note -

S3L_read_sparse assumes that row and column indices are stored using zero-based indexing when called by C or C++ applications and one-based indexing when called by F77 or F90 applications.

This is illustrated by the following 4x6 sample matrix.

 3.14       0          0        20.04        0          0
 0         27          0          0         -0.6        0
 0          0         -0.01       0          0          0
-0.031      0          0          0.08       0        314.0

This sample matrix could have the S3L_SPARSE_COO files consist of three sections, which are below and described immediately after.

% Example: 4x6 sparse matrix in an S3L_SPARSE_COO file, 

% row-major order, zero-based indexing:
%
%
4       6       8
0       0       3.140e+00
0       3       2.004e+01
1       1       2.700e+01
1       4      -6.000e-01
2       2      -1.000e-02
3       0      -3.100e-02
3       3       8.000e-02
3       5       3.140e+02

The layout used for this example is row-major, but any order is supported, including random. The next two examples show this same 4x6 matrix stored in two S3L_SPARSE_COO files, both in random order. The first example illustrates zero-based indexing and the second one-based indexing.

% Example: 4x6 sparse matrix in an S3L_SPARSE_COO file, 

% random-major order, zero-based indexing:
%
%
4       6       8
3       5       3.140e+02
1       1       2.700e+01
0       3       2.004e+01
3       3       8.000e-02
2       2      -1.000e-02
0       0       3.140e+00
1       4      -6.000e-01
3       0      -3.100e-02
 
% Example: 4x6 sparse matrix in an S3L_SPARSE_COO file, 

% random-major order, one-based indexing:
%
%
4       6       8
4       4       8.000e-02
2       2       2.700e+01
1       1       3.140e+00
4       1      -3.100e-02
3       3      -1.000e-02
4       6       3.140e+02
1       4       2.004e+01
2       5      -6.000e-01