Originally posted by: Chen Cong

I'm using Matlab to do some optimization work with YALMIP and Cplex V12.8. And I found the Cplex v12.8 is added to the path, which is shown in the picture below by doing yalmiptest

But actually it cannot work. The yalmiptest('cplex') shows below:

I don't know what's wrong with it. And if I test a small program, use yalmip to choose the solver "cplex", it'll show that the solver is not applicable, like below

Anybody can help me ?

You would have to add more details about your problems before anybody can help you. What exactly does "it cannot work" mean?

Originally posted by: Chen Cong

Thank you very much!!! I've added explanation in detail.

Could it be that you are mixing 32bit matlab with 64bit CPLEX?

Also did you check in the detailed system requirements that your version of matlab is supported by CPLEX?

Originally posted by: Chen Cong

Thank you ! My system is window 7 professional with 64 bits, which matches the YALMIP and CPLEX v12.8 and I think it can support. I think maybe its because the latest YALMIP cannot call the CPLEX v12.8?? But I don't know how to solve it. And it's also unknown how to use YALMIP to se the Benders parameter of CPLEX v12.8.

Did you check with YALMIP people? Also, did you turn on this debug parameter as suggested in the error message?

Originally posted by: Chen Cong

!!you remind me to contact the YALMIP people!  I have tried to trun on the debug parameter. But I don't the debug is in sdpsettings or in all the solver functions like cplexlp, cplexqcp and so on. It seems like all the solver functions cannot be called by the YALMIP to solve any optimization problem. And I only meet this problem in the latest YALMIP and CPLEX.

Originally posted by: Mark L. Stone

Even if you are using a MATLAB version compatible with CPLEX 12.8.0, cplex will not be applicable to your test problem which has constraint F, because that specifies 2 LMIs. LMIs are not within cplex's capabilities. 

Originally posted by: Chen Cong

Thank you!! you remind me of the errors in my sample. But I think there still exists problem in the the latest YALMIP and CPLEX.. As you can see in the second picture. The yalmiptest('cplex') shows all the solver functions in CPLEX meet unknown problem in solver. And I've try to use it to solve some LP. It still cannot worl,and shew that "meet unknown problem in solver". It seems like all the solver functions cannot be called by the YALMIP to solve any optimization problem. And I only meet this problem in the latest YALMIP and CPLEX..

Originally posted by: Mark L. Stone

You haven't stated what version of MATLAB you are using.

If you cannot successfully run CPLEX for MATLAB Toolbo functions directly from MATLAB, such as

cplexlp(1,[],[],[],[],0,Inf)

then the problem is not with YALMIP.

If you are running MATLABR2015a or earlier, it may not be compatible with CPLEX 12.8.  Not just not supported, but does not work at all.

Originally posted by: Chen Cong

I've tried the R2014 and R2016 and they cannot support. Thank you very much!! You help me find out the problem!!

Originally posted by: JohanLöfberg

As far as I can tell, 12.8 works as expected in R2017+, but fails to load binary in R2016 and earlier

Fails in R2016 (and R2015)

>> version

ans =

9.1.0.441655 (R2016b)

>> which cplexlink1280
C:\Program Files\IBM\ILOG\CPLEX_Studio128\cplex\matlab\x64_win64\cplexlink1280.mexw64
>> cplexlink1280
Invalid MEX-file 'C:\Program
Files\IBM\ILOG\CPLEX_Studio128\cplex\matlab\x64_win64\cplexlink1280.mexw64': The
specified module could not be found..
 

Works in R2017 (and R2018)

>> version

ans =

    '9.3.0.713579 (R2017b)'

>> which cplexlink1280
C:\Program Files\IBM\ILOG\CPLEX_Studio128\cplex\matlab\x64_win64\cplexlink1280.mexw64
>> cplexlink1280
Error using cplexlink1280
At least 2 input required

Originally posted by: Chen Cong

Thank you very much!! Your words help me a lot!!! I've tried this on R 2014 and R2016 and they don't support. It depressed me a lot and you help me find out the problem！I failed to test the version match or not. Thank you again!! And actually YALMIP help me a lot in my research !!