FICO Xpress Optimization Examples Repository: Basic MIP tasks: binary variables; logic constraints

FICO Xpress Optimization Examples Repository

Basic MIP tasks: binary variables; logic constraints

Description

We wish to choose among items of different value and weight those that result in the maximum total value for a given weight limit.

Further explanation of this example: 'Xpress Python Reference Manual'

burglar_python.zip

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Source Files

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burglar.py	[download]
burglari.py	[download]
burglarl.py	[download]
burglar_rec.py	[download]
knapsack.py	[download]

Data Files

burglar_rec_dat.py

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knapsack.py

# Example of a knapsack problem formulated with the Xpress Python interface.
#
# (C) 1983-2025 Fair Isaac Corporation

import xpress as xp
import numpy as np

S = range(5)                                # The set {0,1,2,3,4}
value = np.array([102, 512, 218, 332, 41])
weight = np.array([21, 98, 44, 59, 9])

p = xp.problem("knapsack")

x = p.addVariables(5, vartype=xp.binary)
profit = xp.Dot(value,x)

p.addConstraint(xp.Dot(weight,x) <= 130)
p.setObjective(profit, sense=xp.maximize)

p.optimize()