RB, a data directory which contains examples of the RB or Rutherford Boeing Sparse Matrix File Format, used to store a sparse matrix in a file.
Since most of the matrix is presumably zero, a great deal of storage can be saved if only the nonzero entries are stored. The file format offers a choice of two suitable representations for the nonzero data: a compressed column storage (CCS) format, or a format suitable for finite element matrices.
The two representations, compressed column storage or finite element, may then be stored in a file using either the Rutherford Boeing format (RB) or a Matrix Market format (MM).
Often, a sparse matrix has associated information, such as eigenvectors, or special right hand sides. The RB format offers a way to include such information in files, so that it is associated with the sparse matrix and retrieved as needed. The Harwell-Boeing format, a predecessor to the RB format, required all supplementary information to be included in the same file as that storing the sparse matrix.
The information on this web page is distributed under the MIT license.
HB, a data directory which contains examples of HB files, the Harwell Boeing sparse matrix file format;
MM, a data directory which contains examples of MM files, the Matrix Market Sparse Matrix File Format;
EXAMPLE1 is a 5x5 real general matrix. Thanks to Liang Tang for suggestion a correction to the RB file.
EXAMPLE2 is a 10x10 square symmetric matrix in elemental form. The matrix is formed as the sum of 6 symmetric 3x3 matrices and one symmetric 4x4 matrix. Because symmetry is specified, only the diagonal and lower triangle of these matrices are to be supplied.
EXAMPLE3 is a 5x5 square matrix in elemental form. The matrix is not symmetric, but it is structurally symmetric. The matrix is formed as the sum of 4 square finite element matrices.
EXAMPLE4 is a 4x5 small rectangular matrix in elemental form. The matrix is formed as the sum of 3 rectangular finite element matrices.