A few years ago I integrated successfully several Callable Library routines (CPLEX7.1) in programs written in Delphi 5. The objective was to solve integer linear programming problems.

Recently, through the Academic Initiative program, I updated to the IBM ILOG CPLEX 12.5 and also I updated to a new version of Delphi, Embarcadero RAD Studio XE. However I started having some problems.

Some functions called through cplex12.5.dll continue to work well: CPXopencplex, CPXcreateprob, CPXchobjsense, CPXnewcols and CPXadrrows. The problems start when I call the solving function CPXmipopt.

I tried to use first the function CPXwriteprob but result an error 1424-Invalidate filetype. These are programs that have worked perfectly with previous versions and I also checked all the file extensionsadmissible in CPXwriteprob.

Can anyone help me?

Attached follows a small program that aims to solve a small problem whose solution is x1 = 3, x2 = 2.

Max Z = 5x1 +4 x2

st

x1 + x2 <= 5

10x1 +6 x2 <= 45

x1, x2> = 0 and integers.

This program, in Delphi, use a unit CplexDLL that make the link with cplex12.5.dll callable Library.