diff --git a/.idea/Model.iml b/.idea/Model.iml index 0ded8e60..05b9012b 100644 --- a/.idea/Model.iml +++ b/.idea/Model.iml @@ -7,7 +7,7 @@ - + \ No newline at end of file diff --git a/.idea/misc.xml b/.idea/misc.xml index ae87bfde..3b05c6ac 100644 --- a/.idea/misc.xml +++ b/.idea/misc.xml @@ -1,6 +1,6 @@ - + diff --git a/model_data/optimiser/CostOptimiser.py b/model_data/optimiser/CostOptimiser.py index e9ef9313..de5a9e11 100644 --- a/model_data/optimiser/CostOptimiser.py +++ b/model_data/optimiser/CostOptimiser.py @@ -1,4 +1,7 @@ -from mip import Model, xsum, minimize, BINARY +from mip import Model, xsum, minimize, BINARY, OptimizationStatus +from utils.logger import setup_logger + +logger = setup_logger() class CostOptimiser: @@ -9,6 +12,7 @@ class CostOptimiser: def __init__(self, components, min_gain): self.components = components self.min_gain = min_gain + self.gain_constraint = None self.m = None self.variables = [] self.solution = [] @@ -42,21 +46,51 @@ class CostOptimiser: # This constrain ensures that sum of gain_ig * x_ig >= min_gain, where gain_ig represents the gain for the ith # component # in group g, and x_ig is the binary decision variable for the ith component in group g - self.m += xsum( + gain_expression = xsum( item['gain'] * var for group, group_vars in zip(self.components, self.variables) for item, var in zip(group, group_vars) ) >= self.min_gain + self.gain_constraint = self.m.add_constr(gain_expression) + # At most one item from each group # This constraint ensures that at most one item from each group is selected # This is expressed by summing up the decision variables for each group and ensuring that the sum is <= 1 for group_vars in self.variables: self.m += xsum(var for var in group_vars) <= 1 + def setup_slack(self): + + # Remove the original gain constraint + self.m.remove(self.gain_constraint) + # Add slack variable + s = self.m.add_var(lb=0) + + # Modify the constraint + self.m += xsum( + item['gain'] * var for group, group_vars in zip(self.components, self.variables) for item, var in + zip(group, group_vars) + ) + s >= self.min_gain + + # Modify the objective to penalize the use of slack + penalty = 10000 # you can adjust this based on how much you want to penalize the use of slack + self.m.objective = minimize( + xsum( + component['cost'] * var for group, group_vars in zip(self.components, self.variables) for component, var + in + zip(group, group_vars) + ) + penalty * s + ) + def solve(self): # Solve the problem self.m.optimize() + if self.m.status == OptimizationStatus.INFEASIBLE: + logger.info("We have an infeasible model, setting up slack model") + self.setup_slack() + self.m.optimize() + self.solution = [ item for group, group_vars in zip(self.components, self.variables) for item, var in zip(group, group_vars) if