Originally posted by: JohanLöfberg

Display/diagnostic options do not work as (I) expected.

12.5: Creating an options structure and then changing the diagnostic field works to turn on some display

>> ops = cplexoptimset('cplex');
>> ops.diagnostics = 'on';
>> cplexlp(1,-1,1,[],[],[],[],[],ops)
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 1 columns.
All rows and columns eliminated.
Presolve time = 0.00 sec. (0.00 ticks)

12.6: The diagnostic field is gone. The field display is there but makes no difference

>> ops = cplexoptimset('cplex');
>> ops.display = 'on';
>> cplexlp(1,-1,1,[],[],[],[],[],ops);

Creating a new field with capital D works though

>> ops = cplexoptimset('cplex');
>> ops.Display = 'on';
>> cplexlp(1,-1,1,[],[],[],[],[],ops);Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 1 columns.
All rows and columns eliminated.
Presolve time = 0.00 sec. (0.00 ticks)

Intended behaviour? What is the logic then?

Originally posted by: RWunderling

Yes, this is intended behaviour:

The CPLEX Matlab toolbox functions try to mimic the functionality provided by the matlab toolbox, including the parameters, in order to help users moving to CPLEX.  Thus the changes done by Matlab (see http://www.mathworks.de/de/help/optim/ug/optimization-options-reference.html for the current optimization settings) have been tracked with this CPLEX version.

Originally posted by: JohanLöfberg

So if I want to alter a number of solver parameters, and turn on display from presolve, I should add the non-existant field Display to the automatically created options structure, or should there be some other pattern in the way I work

Originally posted by: RWunderling

For the toolbox function parameters, there are two sets:

1.  A set of compatilibity parameters to the Matlab toolbox parameters.  Here we try to interprete the parameters from the toolbox the best we can.  But since the toolbox algorithms are different from the CPLEX algorithms, it should not come as a surprise that some parameters from the toolbox are not supported by CPLEX and vice versa.  To get access to the full set of CPLEX parameters while still using the toolbox functions, you should use

2. A set of CPLEX parameters.  This is the full set of CPLEX parameters following the standard hierarchy as you may be used from interactive cplex.  To get the full list you can do the following in matlab:

>> s = cplexoptimset('cplex');
>> s

s =

           advance: 1
           barrier: [1x1 struct]
         clocktype: 2
          conflict: [1x1 struct]
      dettimelimit: 1.0000e+75
           distmip: [1x1 struct]
          emphasis: [1x1 struct]
           feasopt: [1x1 struct]
          lpmethod: 0
               mip: [1x1 struct]
           network: [1x1 struct]
            output: [1x1 struct]
          parallel: 0
     preprocessing: [1x1 struct]
          qpmethod: 0
        randomseed: 201309011
              read: [1x1 struct]
           sifting: [1x1 struct]
           simplex: [1x1 struct]
    solutiontarget: 0
           threads: 0
         timelimit: 1.0000e+75
              tune: [1x1 struct]
           workdir: '.'
           workmem: 2048
           display: 'off'
       exportmodel: ''
 

Roland

Originally posted by: JohanLöfberg

Exactly, so how should I use this set of options created using cplexoptimset('cplex') to turn on presolve display. The field 'display' does not work for that.

Or put differently, what is the field 'display' used for, since it does not help to set it to 'on' to get any display

Originally posted by: RWunderling

Now I see, sorry.  You did point out a problem with the display parameter in the 'cplex' options.  The workaround is indeed to mix toolbox and cplex options by using 'Display' with capital 'D' with the cplex options. Thank you for the problem report.

Generally, CPLEX attempts to interpret both the toolbox and cplex options, as long as they are not defined in a contradictory way.