Hello
I have been trying to extract information for extreme ray for an unbounded primal Linear Program and certificate of infeasibility for an infeasible primal Linear Program, from CPLEX callable in GAMS without success.
I have looked at the GAMS solver manual but can't seem to get any of such information.
Can anybody direct me on how to obtain such information (i mean the codes in GAMS)in CPLEX run in GAMS?
Additionally I am equally using MATLAB. So If it's not possible in GAMS, then I was wondering if I can at least get these information from MATLAB (code in matlab) calling CPLEX.
I need this help please!
Thanks
Topic

Re: Obtaining extreme ray and certificate of infeasibility of an LP
20130117T07:02:15ZThis is the accepted answer. This is the accepted answer.I don't know about GAMS but a frequent problem with getting such a ray is that the model is blatantly infeasible and infeasibility is already proven in presolve. In that case no ray is available. Can you please disable presolve and see if the problem persists? 
Re: Obtaining extreme ray and certificate of infeasibility of an LP
20130117T08:39:18ZThis is the accepted answer. This is the accepted answer. SystemAdmin
 20130117T07:02:15Z
I don't know about GAMS but a frequent problem with getting such a ray is that the model is blatantly infeasible and infeasibility is already proven in presolve. In that case no ray is available. Can you please disable presolve and see if the problem persists?