I don't think this has anything to do with VEDA. As far as I know, VEDA does not give any messages like this, and so I am rather confident that VEDA is not guilty of this problem.
I have never seen this message myself, but searching a bit on the Internet, I found some discussions about Cplex producing exactly that message when returning the status code CPX_STAT_NUM_BEST.
So it seems the message may be produced by Cplex. If so, maybe consider using Gurobi instead?
19-02-2016, 03:17 AM
(This post was last modified: 16-12-2017, 10:32 PM by
Antti-L
.
Edit Reason: fixed mess due to new forum software
If you want to know the exact reason for the numerical problems of the solver you are using, I am afraid there is no general answer. Numerical problems can be caused by a wide variety of conditions which may occur more or less randomly during the solution algorithm.
See a general discussion about handling numerical difficulties here (with focus on Cplex):
https://www.ibm.com/support/knowledgecen...culty.html
A few additional recommendations for avoiding numerical problems can be given specifically in relation to TIMES:
Check the QA_check.log for errors and warnings, and at least eliminate any free output flows if such are listed there;
Disable any “dummy import” processes if such have been used in your model (use e.g. PRC_NOFF to remove them from the model);
If you have been using very high costs for any other processes in order to prevent them entering the solution, remove such processes altogether e.g. by using PRC_NOFF
;
Check for any very high upper bounds specified and consider reducing them or removing them altogether if they are not necessary;
Check all your market share and user constraints for mutually redundant equations, and remove if such found;
Check for any zero-cost commodity flows that could become arbitrarily large, and add either small costs
or
reasonable bounds for
them if such are found.
