A simple supply and demand network example showing data input from file and the use of "views": incremental definition of arrays of variables. Also uses constraint templates with the arrays of variables.

A second version of this model (file xbdlvriis) has modified data making the problem infeasible. This example shows how to analyze infeasibility with the help of IIS (irreducible infeasible sets), it retrieves the IIS and prints out their contents.

It is possible to retrieve more detailed information on the IIS, such as isolation rows or bounds, using Xpress Optimizer functions (file xbdlvriis2iso) or to use the infeasibility repair functionality of the Optimizer (file xbdlvriis2rep) with models defined in BCL.

! Delivery Problem
! Data File: ifvan.dat
!
! Table IFVAN: Contains non-zero if route requires vans
!
!
! TO  London Livpol Doncst  York   Hull  Manchr Shffld   ! FROM
        1,     1,     0,     1,     0,     0,     0      ! London
        0,     1,     1,     0,     1,     1,     0      ! Luton
        0,     0,     0,     0,     0,     0,     0
        0,     0,     0,     0,     0,     0,     0
        0,     0,     0,     0,     0,     0,     0
        0,     0,     0,     0,     0,     0,     0                       
        0,     0,     0,     0,     0,     0,     0
        0,     0,     0,     0,     0,     0,     0
        0,     0,     0,     0,     0,     0,     0
        1,     1,     1,     1,     1,     0,     0      ! Scnthp