Hi Andrew, Under the heading "BOUNDS Section" and the subheading "Default Bounds," the OSL manual says the following:
"For integer variables, the default bounds on columns are 0 and 1. (WARNING, if you want a very large bound for an integer variable, explicitly set it to 1020. DO NOT specify a value larger than 1020, or leave the value unspecified, thinking that the result will be "unbounded.")" Hope this clarifies things. Perhaps John Forrest could comment. Cheers, Ted Andrew Makhorin wrote: >>Yes, this is exactly the problem. According to the MPS standard, any >>integer variable without bounds is assumed to be binary. The COIN MPS >>reader complies with this standard, but not all readers do (GLPKs reader >>does not, for instance). > > > OSL documentation says (chapter "Passing Your Model Using Mathematical > Programming System (MPS) Format", section "Integer Data"): > > General Integer Variables > > For general integer variables, the following indicates the > various values you may use for the fields: > > If you are defining general integer variables, field 1 must > be blank and field 5 must contain the value 'INTORG' > (including the quotation marks) in the record that denotes > the start of integer variables. In the record that denotes > the end of integer variables, field 1 must be blank and > field 5 must contain the value 'INTEND'. > > You can select any name for field 2 as long as it is > different from the preceding and following column names. > > Field 4, although ignored, must be blank in free format. > > All variables between the INTORG and INTEND markers are > taken as integer variables if the intunit parameter in > the call to EKKMPS is nonzero. > > And this is clarified by the following example: > > The following is an example of defining general integer > variables: > > *234567890123456789012345678901234567890123456789012345678901234567890 > COLUMNS > COL01 OBJ 1.0 > COL01 ROW01 3.0 ROW05 5.6 > COL02 ROW01 1.0 ROW02 2.0 > * > * Mark COL03 and COL04 as integer > * > INT1 'MARKER' 'INTORG' > COL03 ROW02 1.1 ROW03 1.0 > COL04 ROW01 -2.0 ROW04 2.8 > INT1END 'MARKER' 'INTEND' > * > COL05 OBJ 2.0 > COL05 ROW01 -1.0 ROW05 1.0 > COL06 ROW03 1.0 > COL07 ROW04 -1.2 > COL08 OBJ -1.0 > COL08 ROW01 -1.0 ROW05 1.9 > > Here, the columns named COL03 and COL04 must take on integer > values. > > I didn't find any points that "any integer variable without bounds is > assumed to be binary". > > Andrew Makhorin, > maintainer of glpk > > (Sorry, if my message sent twice due to incorrect clock settings.) -- Dr. Ted Ralphs Assistant Professor Industrial and Systems Engineering Lehigh University (610)758-4784 [EMAIL PROTECTED] www.lehigh.edu/~tkr2 _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
