QSprob QSread_prob (const char *filename, const char *filetype)

This function can read LP problems in either MPS format or in LP format. To specify MPS format, set filetype to "MPS" (the letters can be any mix of uppercase and lowercase), and to specify LP format, set filetype to "LP". If some other string is specified, an error code will be returned.

MPS format is a standard file format for recording LP problems. The format was created at IBM in the 1960s, and the original standard included fixed-column information (a common feature in the days of punched cards). An introduction to the format can be found at ftp://plato.asu.edu/pub/mps_format.txt. The QSopt MPS reader follows a number of other modern LP solvers in removing the fixed-column aspects of the format.

LP format is a well-established format for recording algebraic representations of LP problems, in a natural, row by row, manner. The QSopt LP format is compatible with the standard usage of the LP file format incorporated in other LP solvers.

A complete description of the two formats used in QSopt is given in Problem Formats.

QSprob p;

/* Read a problem in MPS format given in the file binky.mps */

p = QSread_prob ("binky.mps", "MPS");
if (p == (QSprob) NULL) {
    fprintf (stderr, "Unable to read and load the LP\n");
} else {
    /* We can solve and/or modify the problem using the handle p */
}