import xpress as xp
# Creates a problem and read a MIPLIB2010 instance
p = xp.problem()
p.read('miplib-rndinst.mps.gz')
# Create a file default-MIP.xtm with the tuner options that are tested
# by default by the tuner. The file has the following format: a
# section with controls that are applied to each tuner run
# ("FIXED-CONTROLS") and a set of controls that are tested
# independently by the tuner ("TUNABLE-CONTROLS"). Tunable controls
# have each one or more value that the tuner will test, first
# independently and then in combination with others.
#
# FIXED-CONTROLS
# OUTPUTLOG = 1
# XSLP_POSTSOLVE = 1
# TUNABLE-CONTROLS
# BRANCHDISJ = 0
# COVERCUTS = 0, 2, 20
# CUTFACTOR = 0.5, 1, 5
# CUTFREQ = 2
#
# ... and others. The file is written AFTER reading in the problem in order
# for the optimizer to recognize that it is a MIP.
p.tunerwritemethod('default-MIP.xtm')
# Set the total amount of time the tuner can spend in tuning
# (tunermaxtime) and the time limit for each run.
p.controls.tunermaxtime = 100
p.controls.timelimit = 10
# Tune the optimizer on the problem
p.tune('g')
# Now try tuning on a different tuner method: the file mymethod.xtm
# contains slightly different combination of controls and values, and
# the tuner will test different combinations this way. Note that the
# output will show that the Optimizer finds old tuner runs and will
# use the relative information
p.tunerreadmethod('mymethod.xtm')
p.tune()
# Finally, before solving the problem, increase the time limit.
p.controls.timelimit = 1000
p.optimize()
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