Automatic relaxations

The following constraints can be relaxed automatically with Xpress Kalis :

• Linear constraints
• all-different
• occurrence
• distribute
• Min/Max
• absolute value
• distance
• element
• cycle
• logical (implies, or ,and ,equiv)

To obtain an automatic relaxation of the whole problem, Xpress Kalis takes the intersection of the relaxations of the constraints of the constraint programming model. Such a relaxation is obtained by a simple call to the function cp_get_linrelax

Note that this method is parameterized with an integer parameter since Xpress Kalis offers several relaxations for each constraint. In the present case, 0 means an LP oriented relaxation and 1 means a MIP oriented relaxation.