Originally posted by: daxingxing

I am trying to solve a quadratic constraint problem using cplex. When I ran the program, there's an error saying that 'matlab has encounted an internal problem'. I have 54 quadratic constraints, which is not too much. I followed the right format of cplex qcp. So, what would be the problem? Thanks for your help.

It looks like you're using 12.5.1.  Can you upgrade to 12.6.0.1 (the latest release)?  This may fix your problem.  Otherwise, can you share your model with us, so we can try to reproduce?  You can write the model just before calling solve (e.g., with the writeModel method).  Can you reproduce the crash using the interactive with this model file?

Originally posted by: daxingxing

Thank you very much for the reply. Below is the code of my model. First one is the main function, second one is the qcp funciton.

Originally posted by: daxingxing

The code is too long to be pasted so I attached it. It would be nice if you can reproduce it. Thanks.

Originally posted by: daxingxing

Hi, I updated cplex to the latest version. It shows the reason of the error.

So, is it possible to fix it, or I have to use another solver?

Thanks!

Details on the Academic Initiative can be found here.

Originally posted by: daxingxing

The latest version is only a preview version. So if I use the preview 12.6.0.1, the error would be 'Restricted version.  Problem size limits exceeded.' If I use academic initiative version 12.5, the error would be   'matlab has encounted an internal problem'.

I could be wrong, but I'm pretty sure you can download the latest version (12.6.0.1) through the academic initiative.  This seems like the path of least resistance.  Is there some reason why you can't do this?

Originally posted by: daxingxing

There's only one choice in the download of cplex. It is 'IBM ILOG CPLEX Optimisation Studio 12.6', the version is 12.6.0.0. I just downloaded it and checked the version in the control panel.

Sorry, you are correct.  The fix packs are not available to AI users (I forgot about this).  However, you should still try 12.6.0.0.  That version will not have the problem size limitations and it's possible a bug has been fixed that you are running into with 12.5.

Originally posted by: T_O

A while ago, I was able to download 12.6.0.0 from the Academic Initiative and the 12.6.0.1 fixpack. So it should at least be possible to install 12.6.0.1.

Originally posted by: daxingxing

Unfortunately 12.6.0.1 still encounted the same problem.

Thanks for going through the motions (i.e., upgrading to the latest version).  I've reproduced your error, but I'm not yet sure of the cause.  I'll let you know when we have more information.

Originally posted by: daxingxing

Thank you very much! I think the main problem lies in the quadratic constraints. If I delete the quadratic constraints and perceive the model as a QP problem, the solver works. I don't know what's wrong with my quadratic constraints.