MM_IO
Matrix Market
Read and Write Utilities

MM_IO is a FORTRAN77 library which reads and writes files in the Matrix Market (MM) format.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

MM_IO is available in a C version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

CC_IO, a FORTRAN77 library which reads and writes sparse linear systems stored in the Compressed Column (CC) format.

DLAP_IO, a FORTRAN77 library which reads and writes files describing sparse matrices used by DLAP.

HB_READ, a FORTRAN77 library which reads files in the Harwell Boeing (HB) sparse matrix format; This is a simplified interface intended to handle only the most common format, complex unsymmetric assembled (CUA) or real unsymmetric assembled (RUA).

MM, a data directory which contains a description and examples of the Matrix Market format for storing matrices.

SPARSE_DISPLAY, a FORTRAN77 library which can read information defining a matrix of numbers and display the sparsity pattern or location of the nonzero elements using gnuplot. This operation is already available in the built-in MATLAB "spy" command.

ST_IO, a FORTRAN77 library which reads and writes sparse linear systems stored in the Sparse Triplet (ST) format.

TEST_MAT, a FORTRAN77 library which defines various test matrices.

Reference:

1. Ronald Boisvert, Roldan Pozo, Karin Remington,
   The Matrix Market Exchange Formats: Initial Design,
   National Institute of Standards and Technology,
   NISTIR 5935, December 1996.
2. http://math.nist.gov/MatrixMarket/, the Matrix Market web site.

Source Code:

• mm_io.f, the source code.
• mm_io.sh, commands to compile the source code.

Examples and Tests:

• mm_io_prb.f, a sample calling program.
• mm_io_prb.sh, commands to compile and run the sample program.
• mm_io_prb_output.txt, the output file.
• matrix_05_05_crg.txt, a 5 by 5 matrix in COORDINATE REAL GENERAL form read by some routines, and written by others.
• wathen_29_28_adg.txt, a 29 by 29 matrix in ARRAY DOUBLE GENERAL form written by one of the test routines.

List of Routines:

• CH_CAP capitalizes a single character.
• GET_UNIT returns a free FORTRAN unit number.
• MM_COMMENT_PRINT prints a comment from a Matrix Market file.
• MM_COMMENT_READ reads a comment from a Matrix Market file.
• MM_COMMENT_WRITE writes a comment to a Matrix Market file.
• MM_FILE_READ reads data from a Matrix Market file.
• MM_FILE_WRITE writes data to a Matrix Market file.
• MM_HEADER_CHECK checks the header strings for a Matrix Market file.
• MM_HEADER_PRINT prints header information from a Matrix Market file.
• MM_HEADER_READ reads the header line from a Matrix Market file.
• MM_HEADER_WRITE prints header information to a Matrix Market file.
• MM_NNZ_SET sets the value of NNZ for the ARRAY representation.
• MM_SIZE_PRINT prints size information from a Matrix Market file.
• MM_SIZE_READ_FILE reads size information from a Matrix Market file.
• MM_SIZE_READ_STRING reads size information from a string.
• MM_SIZE_WRITE writes size information to a Matrix Market file.
• MM_VALUES_PRINT prints the matrix values of a Matrix Market file.
• MM_VALUES_PRINT_SOME prints some matrix values of a Matrix Market file.
• MM_VALUES_READ reads matrix values from a Matrix Market file.
• MM_VALUES_WRITE writes matrix values to a Matrix Market file.
• S_EQI is a case insensitive comparison of two strings for equality.
• S_NEQI compares two strings for non-equality, ignoring case.
• S_TO_I4 reads an I4 from a string.
• S_TO_I4VEC reads an I4VEC from a string.
• S_W_NEXT "reads" words from a string, one at a time.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the FORTRAN77 source codes.