Originally posted by: s.st1led

Hi everybody, I posted this issue in the CP forum, but after some further testing I found out this also applies to Cplex so it's relevant also here (and, to be fully honest, this forum looks much more active than the CP one :). At this point, I'm thinking it might be a bug. I report my further test here, even though it's basically the same as the other.

I'm using the x64 library delivered with CPLEX Optimization Studio 12.5.1 under Windows 8 x64 and Visual Studio 2012. Let's assume I have this pretty straightforward code:

            // Initializes the OPL Factory and Error Handler
            OplFactory.DebugMode = false;
            OplFactory oplFactory = new OplFactory();
            OplErrorHandler oplErrorHandler = oplFactory.CreateOplErrorHandler();

            // Initializes the OPL Run Settings
            OplSettings oplSettings = oplFactory.CreateOplSettings(oplErrorHandler);
            oplSettings.setWithWarnings(false);

            // Initializes the OPL Model
            OplModelSource oplModelSource = oplFactory.CreateOplModelSource(@"model.mod");
            OplModelDefinition oplModelDefinition = oplFactory.CreateOplModelDefinition(oplModelSource, oplSettings);

            // Initializes the OPL Data
            OplDataSource oplDataSource = oplFactory.CreateOplDataSource(@"data.dat");


            // Initializes the Cplex solver
            ILOG.CPLEX.Cplex cplex = oplFactory.CreateCplex();
            
                StreamWriter streamWriter = File.CreateText(@"log.log");
                TextWriter synchronizedStreamWriter = TextWriter.Synchronized(streamWriter);
                cplex.SetOut(synchronizedStreamWriter);

            // Instantiates the OPL Model
            OplModel oplModel = oplFactory.CreateOplModel(oplModelDefinition, cplex);

           
            oplModel.AddDataSource(oplDataSource);

            // Generates the OPL Model
            oplModel.Generate();

            // Returns the loaded and configured OplModel
            return oplModel;

When I execute it, I have the following runtime execption upon the Cplex.SetOut call:

System.OverflowException was unhandled
  HResult=-2146233066
  Message=Arithmetic operation resulted in an overflow.
  Source=mscorlib
  StackTrace:
       at System.IntPtr.ToInt32()
       at ILOG.Concert.Cppimpl.NotifierStream.initCppCallback()
       at ILOG.Concert.Cppimpl.NotifierStream..ctor(IntPtr cPtr, Boolean cMemoryOwn)
       at ILOG.Concert.Cppimpl.NotifierStream..ctor()
       at ILOG.Concert.Cppimpl.DotnetToCppOutputStreamAdapter..ctor(TextWriter os)
       at ILOG.CPLEX.Cplex.SetOut(TextWriter s)
       at Test.Test.InitializeNewSearch() in Test.cs:line 42
       at Test.Program.Main(String[] args) in Program.cs:line 14
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:
 

Am I doing something wrong? I also tried with Cplex.SetOut(Console.Out), but this same exception is thrown. Basically, every Cplex.SetOut() call (apart from Cplex.SetOut(null)) throws this exception.

Is anyone else experiencing the same thing?

Regards,

Stefano

So far we could not reproduce this issue here. Are you sure you are using a 64bit CPLEX library? Can you please double check and make sure you are not using any 32bit CPLEX DLLs?

Originally posted by: s.st1led

I'm pretty sure I'm using the x64 version, because this is the path of the dll I linked in my project: "C:\Program Files\IBM\ILOG\CPLEX_Studio1251\opl\lib\oplall.dll". Since I'm using Windows 8 x64, the x86 version would have been in the "Program Files (x86)". Moreover, I only installed the x64 version of CPLEX Optimization Studio, and for large enough problems I can manage to have the CPLEX process go beyond 3GB of RAM usage, so it can only be x64.

If you can't reproduce the issue, I'm a bit scared. I also tried with another computer (with the same software involved, Windows 8 x64, VS2012, x64 libraries) and I could reproduce the issue. Furthermore, it also looks like this issue doesn't depend on the specific model that I load. Even this minimal code throws the exception:

OplFactory oplFactory = new OplFactory();
ILOG.CPLEX.Cplex cp = oplFactory.CreateCplex();
cp.SetOut(Console.Out);

What could cause the problem? Some bad compiler setting in VS? The stacktrace of the exception is pretty much meaningless, but the fact it's popping out on two different machines is somehow suspicious.

Regards,

Stefano

Originally posted by: s.st1led

I went a bit further investigating this problem, and I found out that it's something related to the .NET library (not sure about the C++ one, since I didn't test that). For instance, the code above runs just fine with the Java library.

If you can't reproduce it, it might be something related to some settings of my VS project. I also tried creating a fresh new project with only one class that has that 3 lines of code, and I still have the exception. I'm kind of running out of ideas.

We are working on this. We have not been able to reproduce it yet but have not run of ideas either :-) We have also found some internal stuff that looks suspicious but are not yet sure whether this is indeed a problem.

By the way, how much RAM do you have on your machine? Did you by any chance set any option anywhere that would cause memory to be allocated at large addresses rather than small ones?

Originally posted by: s.st1led

Thank you very much Daniel for your support and time you are spending on this. I have 8GB RAM, but I don't think I have set up any kind of option like that: I wouldn't even know where to set it. Might it be a Visual Studio setting hidden somewhere?

We have found the issue. Unfortunately there is no easy workaround. The best workaround I can see at the moment is to use 32bit CPLEX and run your application as a 32bit application.

Originally posted by: s.st1led

Ok, good job. As for now, the constraint model I'm working on is quite large and needs the x64 version for more memory. I guess I'll just wait for a fix. Are there any chances to see a fix in the upcoming 12.6 version?

I'm afraid it might already be too late to get the fix into 12.6. So please do not count on that :-(

Originally posted by: s.st1led

I got an update on this issue (sorry for crossposting on https://www.ibm.com/developerworks/community/forums/html/topic?id=2fe1a563-3e59-4bac-8a57-75049e56ba4d#97e12638-6736-4723-8739-13904e46db8a).

After updating to v.12.6.1, this issue just seems to have gotten worse. Instead of an OverflowException upon calling CPLEX.SetOut(), now I seem to be getting a System.ExecutionEngineException upon calling CPLEX.Next() later in the code. For some obscure reason I'm not even able to catch this exception with try/catch statements, so upon execution my program simply crashes.

This is the (not very meaningful) exception log that I get in Visual Studio:

System.ExecutionEngineException was unhandled
  HResult=-2146233082
  Message=Exception of type 'System.ExecutionEngineException' was thrown.
  InnerException:

Any update from IBM side?

Regards,

Stefano

The Overflow issue related to SetOut() should be fixed in 12.6.1. This ExecutionEngineException seems to be something else.

I am not clear what you mean by function CPLEX.Next(). The Cplex class does not define a 'Next()' method. So what exactly are you doing?

Originally posted by: s.st1led

I'm sorry, that was a wrong copy/paste from the CP example in the other thread. I meant CPLEX.Solve(). I past a fresh new MWE that results in this error. Mind that I'm using the 64bit version of the library: I didn't have a chance yet to test with the 32bit one.

            // Initializes the OPL Factory and Error Handler
            OplFactory.DebugMode = false;
            OplFactory oplFactory = new OplFactory();
            OplErrorHandler oplErrorHandler = oplFactory.CreateOplErrorHandler();

            // Initializes the OPL Run Settings
            OplSettings oplSettings = oplFactory.CreateOplSettings(oplErrorHandler);
            oplSettings.setWithWarnings(false);

            // Initializes the OPL Model
            OplModelSource oplModelSource = oplFactory.CreateOplModelSource(@"model.mod");

            OplModelDefinition oplModelDefinition = oplFactory.CreateOplModelDefinition(oplModelSource, oplSettings);

            // Initializes the OPL Data
             OplDataSource oplDataSource = oplFactory.CreateOplDataSource(@"data.dat");


            // Initializes the CP solver
            ILOG.CPLEX.Cplex cplex = oplFactory.CreateCplex();

            StreamWriter streamWriter = File.CreateText(@"TestLogCplex.log");
            TextWriter synchronizedStreamWriter = TextWriter.Synchronized(streamWriter);
            cplex.SetOut(synchronizedStreamWriter);



            // Instantiates the OPL Model
            OplModel oplModel = oplFactory.CreateOplModel(oplModelDefinition, cplex);




            // Adds the data source to the model
            oplModel.AddDataSource(oplDataSource);

            // Generates the OPL Model
            oplModel.Generate();


            // Solves the model
            while (oplModel.Cplex.Solve() == false)
            {
                // Sets the optimal value
                double objectiveValue = oplModel.Cplex.ObjValue;

                Console.Out.WriteLine(objectiveValue);
            }

            // Terminates the Program
            Console.WriteLine(Environment.NewLine + "Press any key to exit");
            Console.ReadKey();

Upon the Cplex.Solve() call, I get the ExecutionEngineException. This happens every time I call Cplex.SetOut() with a non-null argument before the Solve call.

Regards,

Stefano

Sorry, I cannot reproduce this here with CPLEX 12.6.1 on 64bit Windows and Visual Studio 2012. What is your exact setup? What CPLEX assembly do you use (oplall.dll?). Have you configured your project for AnyCPU or for x64?

Could you please post the exception details here (with all InnerException frames expanded)? Maybe we can spot the problem from that.

Originally posted by: s.st1led

I'm running CPLEX 12.6.1 x64 on Windows 8.1 x64 and Visual Studio 2013. In the reference of the projects I added the oplall.dll file that is located in C:\Program Files\IBM\ILOG\CPLEX_Studio1261\opl\lib\. The exception happens both when I configure the project for AnyCPU and for x64.

When I execute the code I get a System.ExecutionEngineException, but unfortunately the exception detail (the one you get when clicking on "Copy exception detail to the clipboard" in the exception popup of VS) is not very meaningful:

System.ExecutionEngineException was unhandled
  HResult=-2146233082
  Message=Exception of type 'System.ExecutionEngineException' was thrown.
  InnerException:

I uploaded a screenshot of the exception snapshot (that I can' copy/paste), which seems to have some more detail. The Data field has a recursive structure that I can't unfold completely, but tell me if you need something specific. Note that the InnerException is null, so there is nothing to show when I expand it in the dialog.

I can sense it is something strange, because I'm not even able to catch the exception with a try/catch construct: the code just crashes bypassing the catch.

Regards,

Stefano

Originally posted by: MattChilcott

Hi Daniel,

we too are experiencing this issue on Windows 8.1 64bit machines.

You indicated there might be a fix in the works - could you tell me approximately when this might be available so I can pass this information on to our customers as a guide?

thanks,

Matt

My colleague updated the correponding thread in the CP Forum. Please check there for more details.

Originally posted by: s.st1led

As I reported on the thread in the CP forums, v12.6.2.0 fixed this issue.

Regards,

Stefano