CC_IO
Read and Write Compressed Column (CC) Sparse Matrix Files

CC_IO is a FORTRAN90 library which reads and writes compressed column (CC) sparse matrix files.

An MxN sparse matrix of NCC nonzero entries in compressed column format is described by three items:

• ccc(), a list of N+1 compressed column indices.
• icc(), a list of NCC row indices.
• acc(), a list of NCC values.

The nonzero entries of column J are stored in locations CCC(J) through CCC(J+1)-1 of ICC and ACC.

Licensing:

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

Languages:

CC_IO is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

CC, a data directory which contains examples of the Compressed Column (CC) sparse matrix file format;

CC_TO_ST, a FORTRAN90 library which converts a sparse matrix from compressed column (CC) to sparse triple (ST) format.

HB_IO, a FORTRAN90 library which reads and writes sparse linear systems stored in the Harwell Boeing (HB) format for sparse matrices.

MM_IO, a FORTRAN90 library which reads and writes sparse linear systems stored in the Matrix Market (MM) format.

ST_IO, a FORTRAN90 library which reads and writes sparse linear systems stored in the Sparse Triplet (ST) format.

ST_TO_CC, a FORTRAN90 library which converts sparse matrix data from Sparse Triplet (ST) format to Compressed Column (CC) format.

Source Code:

• cc_io.f90, the source code.

Examples and Tests:

• cc_io_test.f90 a sample calling program.
• cc_io_test.txt, the output file.

Test #1 and #2 write and read back the information for the "simple" 5x5 matrix with 12 nonzero entries. There are files associated with this.

• simple_acc.txt, the values.
• simple_ccc.txt, the (0-based) compressed column indices.
• simple_icc.txt, the (0-based) row indices.

List of Routines:

• CC_DATA_READ reads data about a sparse matrix in CC format.
• CC_HEADER_READ reads header information about a sparse matrix in CC format.
• CC_PRINT prints a sparse matrix in CC format.
• CC_PRINT_SOME prints some of a sparse matrix in CC format.
• CC_WRITE writes a sparse matrix in CC format to 3 files.
• CH_CAP capitalizes a single character.
• CH_EQI is a case insensitive comparison of two characters for equality.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• FILE_ROW_COUNT counts the number of row records in a file.
• GET_UNIT returns a free FORTRAN unit number.
• I4VEC_DATA_READ reads data from an I4VEC file.
• I4VEC_DEC decrements an I4VEC.
• I4VEC_INC increments an I4VEC.
• I4VEC_WRITE writes an I4VEC file.
• R8VEC_DATA_READ reads data from an R8VEC file.
• R8VEC_WRITE writes an R8VEC file.
• S_TO_I4 reads an I4 from a string.
• S_TO_R8 reads an R8 from a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the FORTRAN90 source codes.