initial commit - add knapsack version 1

 Very basic implementation using pyomo

Author: shinto-dev

.gitignore

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+venv
+.idea

Readme.md

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+Pyomo: https://pyomo.readthedocs.io/en/stable/index.html
+
+Refer
+https://jckantor.github.io/ND-Pyomo-Cookbook/
+
+Github page: https://github.com/Pyomo/pyomo
+
+
+Knapsack

knapsack/__init__.py

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+from pyomo.core import ConcreteModel, Constraint, Objective, Var, maximize
+
+# Problem
+# V = [1, 1, 1, 10, 10, 13, 3]
+# W = [2, 2, 2, 5, 5, 8, 3]
+from pyomo.repn.plugins.baron_writer import Binary
+
+from pyomo_solver.solver_factory import Solver, get_solver
+
+model = ConcreteModel()
+model.x_1 = Var(within=Binary)
+model.x_2 = Var(within=Binary)
+model.x_3 = Var(within=Binary)
+model.x_4 = Var(within=Binary)
+model.x_5 = Var(within=Binary)
+model.x_6 = Var(within=Binary)
+model.x_7 = Var(within=Binary)
+
+model.obj = Objective(
+ expr=model.x_1 + model.x_2 + model.x_3 + 10 * model.x_4 + 10 * model.x_5 + 13 * model.x_6 + 3 * model.x_7,
+ sense=maximize
+)
+
+model.con_0 = Constraint(
+ expr=2 * model.x_1 + 2 * model.x_2 + 2 * model.x_3 + 5 * model.x_4 +
+ 5 * model.x_5 + 8 * model.x_6 + 3 * model.x_7 <= 10
+)
+
+solver = get_solver(Solver.BONMIN)
+results = solver.results(model)
+
+for v in model.component_data_objects(Var):
+ print(str(v), v.value)

knapsack/basic_v1.py

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+import pyomo.environ as pyomo_env
+from enum import Enum
+
+
+class Solver(Enum):
+ CBC = 1
+ BONMIN = 2
+
+
+def get_solver(solver: Solver):
+ return pyomo_env.SolverFactory('./bonmin')

pyomo_solver/__init__.py

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+numpy==1.19.0
+pyomo==5.7