The ILOG CPLEX Interactive Optimizer distributed with the Component Libraries offers a way to see what is going on within the ILOG CPLEX part of your application when you observe peculiar behavior in your optimization application. The commands of the Interactive Optimizer correspond exactly to routines of the Component Libraries, so anomalies due to the ILOG CPLEX-part of your application will manifest themselves in the Interactive Optimizer as well, and contrariwise, if the Interactive Optimizer behaves appropriately on your problem, you can be reasonably sure that routines you call in your application from the Component Libraries work in the same appropriate way.

With respect to parameter settings, you can write a parameter file with the file extension .prm from your application by means of one of these methods:

The Interactive Optimizer can read a .prm file and then set parameters exactly as they are in your application.

Note that MPS, LP and SAV files have differences that influence how to interpret the results of the Interactive Optimizer for debugging. SAV files contain the exact binary representation of the problem as it appears in your program, while MPS and LP files are text files containing possibly less precision for numeric data. And, unless every variable appears on the objective function, ILOG CPLEX will probably order the variables differently when it reads the problem from an LP file than from an MPS or SAV file. With this in mind, SAV files are the most useful for debugging using the Interactive Optimizer, followed by MPS files, then finally LP files, in terms of the change in behavior you might see by use of explicit files. On the other hand, LP files are often quite helpful when you want to examine the problem, more so than as input for the Interactive Optimizer. Furthermore, try solving both the SAV and MPS files of the same problem using the Interactive Optimizer. Different results may provide additional insight into the source of the difficulty. In particular, use the following guidelines with respect to reproducing your program's behavior in the Interactive Optimizer.

If the peculiar behavior that you observed in your application persists in the Interactive Optimizer, then you must examine the LP or MPS or SAV problem file to discover whether the problem file actually defines the problem you intended. If it does not define the problem you intended to optimize, then the problem is being passed incorrectly from your application to ILOG CPLEX, so you need to look at that part of your application.