nmrproject/ILP/caffeinesynthesis.py

100 lines
3.8 KiB
Python

import gurobipy as gp
from gurobipy import GRB, Model, quicksum
HYPEREDGES = {
1: ([], ['Xanthine']),
2: (['Xanthine'], ['p_{0,0}']),
3: (['Xanthine'], ['p_{0,1}']),
4: (['Xanthine'], ['p_{0,2}']),
5: (['p_{0,0}'], ['p_{0,3}']),
6: (['p_{0,0}'], ['p_{0,4}']),
7: (['p_{0,1}'], ['p_{0,3}']),
8: (['p_{0,1}'], ['p_{0,5}']),
9: (['p_{0,2}'], ['p_{0,4}']),
10: (['p_{0,2}'], ['p_{0,5}']),
11: (['p_{0,3}'], ['Caffeine']),
12: (['p_{0,4}'], ['Caffeine']),
13: (['p_{0,5}'], ['Caffeine']),
14: (['Caffeine'], [])
}
#Similyrity of Nodes NMR to Measured NMR
VERTICES = {
1: ([0, 0], ['Xanthine']),
2: ([0, 0], ['p_{0,0}']),
3: ([0, 0], ['p_{0,1}']),
4: ([1, 0], ['p_{0,2}']),
5: ([0, 0], ['p_{0,3}']),
6: ([0, 0], ['p_{0,4}']),
7: ([0, 1], ['p_{0,5}']),
8: ([0, 0], ['Caffeine']),
}
FIXED_FLOWS = {
1: 1,
14: 1,
}
def build_model(name, hyperedges, vertices, excluded_support=None):
model = Model(name)
x = {e_id: model.addVar(vtype=GRB.INTEGER, lb=0, name=f"x_{e_id}") for e_id in hyperedges}
b = {e_id: model.addVar(vtype=GRB.BINARY, name=f"b_{e_id}") for e_id in hyperedges}
vertices = set(v for tails, heads in hyperedges.values() for v in tails + heads)
for v in vertices:
inflow = quicksum(x[e_id] for e_id, (_, heads) in hyperedges.items() if v in heads)
outflow = quicksum(x[e_id] for e_id, (tails, _) in hyperedges.items() if v in tails)
model.addConstr(inflow == outflow, name=f"flow_conservation_{v}")
for e_id, value in FIXED_FLOWS.items():
model.addConstr(x[e_id] == value, name=f"fixed_flow_{e_id}")
for e_id in hyperedges:
model.addGenConstrIndicator(b[e_id], 0, x[e_id] == 0, name=f"unused_implies_zero_{e_id}")
model.addConstr(x[e_id] >= b[e_id], name=f"used_implies_positive_flow_{e_id}")
if excluded_support:
model.addConstr(quicksum(b[e_id] for e_id in excluded_support) <= len(excluded_support) - 1, name="different_hyperedges",)
model.setObjective(quicksum(quicksum(x[v_id]) for v_id in vertices), GRB.MAXIMIZE) #Maximize Similarity of Nodes
return model, x, b
def positive_entries(variable_dict, threshold=0.5):
return {e_id: var.X for e_id, var in variable_dict.items() if var.X > threshold}
def print_solution(title, flow_solution, binary_solution, hyperedges):
print(f"\n{title}:")
for e_id in sorted(flow_solution):
flow = flow_solution[e_id]
tails, heads = hyperedges[e_id]
print(f"Hyperedge {e_id}: Flow = {flow}, Tails = {tails}, Heads = {heads}")
print("\nBinary Variables:")
for e_id in sorted(binary_solution):
print(f"Binary Variable b_{e_id} = {binary_solution[e_id]}")
print(f"\nTotal flow: {sum(flow_solution.values())}")
print(f"Number of used hyperedges: {len(binary_solution)}")
def main():
model, x, b = build_model("HypergraphFlow", HYPEREDGES, VERTICES)
model.optimize()
if model.status != GRB.Status.OPTIMAL:
print("No optimal solution found for the first model.")
return
optimal_solution = positive_entries(x)
optimal_binary_solution = positive_entries(b)
print_solution("Optimal Solution", optimal_solution, optimal_binary_solution, HYPEREDGES)
excluded_support = list(optimal_binary_solution.keys())
second_model, x2, b2 = build_model("SecondBestHypergraphFlow", HYPEREDGES, excluded_support=excluded_support,)
second_model.optimize()
if second_model.status == GRB.Status.OPTIMAL:
second_solution = positive_entries(x2)
second_binary_solution = positive_entries(b2)
print_solution("Second Best Solution", second_solution, second_binary_solution, HYPEREDGES, VERTICES)
else:
print("No optimal solution found for the second best model.")
if __name__ == "__main__":
main()