setting relative mip gap in cplex

[Thomas Bridi]

Hi All, 

I'm trying to set the relative mip gap using the cplex solver

so far i tried this approach

self.opt = SolverFactory('cplex')

self.opt.options['mipgap'] = 0.002

with all the parameters listed in https://www.ibm.com/support/knowledgecenter/SSSA5P_12.8.0/ilog.odms.cplex.help/CPLEX/Parameters/topics/EpGap.html 

However, none of this works. What have I to put into the ticks to make it work?

Thomas

[Rey Guerrero]

Hi Thomas,

Pyomo uses the Interactive "method" in communicating with cplex. Have you tried using the parameter 'mip tolerances gap' as found in the link you mentioned?

Cheers,

Rey

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[Thomas Bridi]

I've tried them all and none of that worked

[sophie...@gmail.com]

Thomas,

Have you tried using "add_options"? I am not using CPLEX, but I was having the same problem specifying options for GAMS solvers (specifically baron). I followed the format for BARON, so I am assuming you can just add an option following CPLEX format. 

Sophie 

[sergio balderrama]

Hello Thomas,

results = opt.solve(instance, tee=True,options_string="mipgap=0.10")

This line is how I set the mip gap.

Regards,

Sergio

[Ebrahim Fawzy]

Solution by  Sergio worked very well.

Thank you <3