ILOG CPLEX 11.0 User's Manual

1. If you can reproduce the behavior with a SAV file, but not with an MPS file, this suggestscorruption or errors in the problem data arrays. Use the DataCheck parameter ordiagnostic routines in the source file check.c to track down the problem.2. If you can reproduce the behavior in neither the SAV file nor the MPS file, the mostlikely cause of the problem is that your program has some sort of memory error. Memorydebugging tools such as Purify will usually find such problems quickly.3. When solving a problem in MPS or LP format, if the Interactive Optimizer issues amessage about a segmentation fault or similar ungraceful interruption and exits, contactILOG CPLEX customer support to arrange for transferring the problem file. TheInteractive Optimizer should never exit with a system interrupt when solving a problemfrom a text file, even if the program that created the file has errors. Such cases areextremely rare.If the peculiar behavior that you observed in your application persists in the InteractiveOptimizer, then you must examine the LP or MPS or SAV problem file to discover whetherthe problem file actually defines the problem you intended. If it does not define the problemyou intended to optimize, then the problem is being passed incorrectly from your applicationto ILOG CPLEX, so you need to look at that part of your application.Make sure the problem statistics and matrix coefficients indicated by the InteractiveOptimizer match the ones for the intended model in your application. Use the InteractiveOptimizer command display problem stats to verify that the size of the problem, thesense of the constraints, and the types of variables match your expectations. For example, ifyour model is supposed to contain only general integer variables, but the InteractiveOptimizer indicates the presence of binary variables, check the type variable passed to theconstructor of the variable (Concert Technology) or check the specification of the ctypearray and the routine CPXcopyctype (Callable Library). You can also examine the matrix,objective, and righthand side coefficients in an LP or MPS file to see if they are consistentwith the values you expect in the model.Eliminating Common Programming ErrorsThis section serves as a checklist to help you eliminate common pitfalls from yourapplication. It includes the following topics:◆ Check Your Include Files on page 141◆ Clean House and Try Again on page 141◆ Read Your Messages on page 141◆ Check Return Values on page 141◆ Beware of Numbering Conventions on page 141140 ILOG CPLEX 11.0 — USER’ S MANUAL