Printing Cut Types and Count

[Andrew Orso]

Hi,

This may be extraordinarily simple though I can't find the appropriate attribute. After a MIP solve, I want to be able to write the type and number of Gurobi cuts (which is displayed in the log file) to a text file. Is there some attribute of the model that lets me do this?

Thanks,

Andrew

[Greg Glockner]

There is no attribute for this, but you can parse the log (using a message callback to capture the info).

[Andrew Orso]

Ok, sounds good. Thanks!

[Carleton Coffrin]

This post is a bit old, so I would like to double check that as of v7.0, this is still the easiest way to count the number of cuts generated?

[Sonja Mars]

Hi,

This is still the way to go:

> There is no attribute for this, but you can parse the log (using a message callback to capture the info).

Best regards,
Sonja


----
Dr. Sonja Mars
Gurobi Optimization - Technical Support

[Carleton Coffrin]

Hi Sonja,

Thanks for the update.  Could you provide a list of all the string names that can be printed out under the "Cutting planes:" output?  It is not immediately clear to me how the cut names in the parameters documentation translate into the names displayed in this log.

Cheers,

-Carleton

[Sonja Mars]

Hi Carleton,

We have the following types that are printed in the log:

User
Learned
Gomory
Cover
Implied bound
Projected Implied bound
Clique
MIR
StrongCG
Flow cover
Flow path
GUB cover
Inf proof
Zero half
Mod-K
Network
Lazy constraints

[Carleton Coffrin]

Thanks Sonja.

For others who might want to do this, here is some python code that is working for me as of v7.0.

m = Model()
...
m._cut_count = 0

m.optimize(cut_counter)

print(m._cut_count)

def cut_counter(model, where):

    cut_names = {

        'Clique:', 'Cover:', 'Flow cover:', 'Flow path:', 'Gomory:', 

        'GUB cover:', 'Inf proof:', 'Implied bound:', 'Lazy constraints:', 

        'Learned:', 'MIR:', 'Mod-K:', 'Network:', 'Projected Implied bound:', 

        'StrongCG:', 'User:', 'Zero half:'}

    if where == GRB.Callback.MESSAGE:

        # Message callback

        msg = model.cbGet(GRB.Callback.MSG_STRING)

        if any(name in msg for name in cut_names):

            model._cut_count += int(msg.split(':')[1])