from .OptimizationProblem import OptimizationProblem
import sys
import io
import gurobipy as gp
from gurobipy import Model, GRB, quicksum
#This class is used to create Quadratic Constrained Programming (QCP) models and also can be extended for Mixed Integer Quadratic Constrained Programming (MIQCP) models.
class QCP(OptimizationProblem):
def __init__(self, problem: dict):
super().__init__(problem) # class create model
#Here we deal with quadratic constraints and objective functions.
#Only at leat one constraint has to be quadratic and the rest can be linear.
#The objective can be linear or quadratic.
#So I need to account for either case
def _create_model(self):
# Direct all output to string buffer to suppress Gurobi console output
old_stdout = sys.stdout
old_stderr = sys.stderr
sys.stdout = io.StringIO()
sys.stderr = io.StringIO()
try:
self._model = Model(self._name)
self._model.setParam('OutputFlag', 0)
self._model.setParam('LogToConsole', 0)
self._addVariables() # Add variables to the model
self._addLinearConstraints() # Add linear constraints to the model
self._addQuadraticConstraints() # Add quadratic constraints to the model
self._addQuadraticObjective()
except Exception as e:
self._model = None
raise e from e
finally:
# Change output back to console
sys.stdout = old_stdout
sys.stderr = old_stderr
