def mip_solver(self):
try:
# create a new model
m = Model("mip_encode")
m.params.outputflag = 0
#m.params.feasibilitytol = 1e-9
#m.params.intfeastol = 1e-9
# add variables
self.add_vars(m)
self.add_additional_vars(m)
# integrate new variables
m.update()
# print("add constr")
# add constraints
self.add_constrs(m)
self.add_spc(m)
if self.objective_type == ObjectiveType.MAX_FLEX_UNCERTAINTY:
m.setObjective(self.Z + 0.0, GRB.MAXIMIZE)
else:
m.setObjective(self.objexp, GRB.MAXIMIZE)
m.update()
m.write("1.lp")
m.optimize()
if m.status == GRB.Status.INF_OR_UNBD:
m.setParam(GRB.Param.Presolve, 0)
m.optimize()
if m.status == GRB.Status.OPTIMAL:
m.write("1.sol")
m.fixed()
return self.get_solution(m)
if m.status != GRB.Status.INFEASIBLE:
print(m.status)
m.computeIIS()
m.write("1.ilp")
except GurobiError as e:
print('Error reported')
print (e.message)
print (e.errno)
solution = Candidate()
solution.utility = -1;
return solution
def get_solution(self, m):
solution = Candidate()
# f = open('sol.txt', 'w')
for var_a in m.getVars():
vname = var_a.getAttr(GRB.Attr.VarName)
if self.objective_type == ObjectiveType.MAX_FLEX_UNCERTAINTY:
if vname.find("cl") == -1 and vname.find("cu") == -1:
continue
#f.write('%s %s\n' % (var_a.getAttr(GRB.Attr.VarName), var_a.getAttr(GRB.Attr.X)))
# if vname.find("l") != -1:
# print(var_a.getAttr(GRB.Attr.VarName), var_a.getAttr(GRB.Attr.X))
e = self.relax_e[vname]
new_relaxation = TemporalRelaxation(e)
if vname.find("cl") != -1:
new_relaxation.relaxed_lb = var_a.getAttr("X")
if new_relaxation.relaxed_lb != e.get_lower_bound():
solution.add_temporal_relaxation(new_relaxation)
else :
new_relaxation.relaxed_ub = var_a.getAttr("X")
if new_relaxation.relaxed_ub != e.get_upper_bound():
solution.add_temporal_relaxation(new_relaxation)
elif self.objective_type == ObjectiveType.MIN_COST:
if vname.find("vlr") == -1 and vname.find("vur") == -1:
continue;
e = self.relax_e[vname]
#print(vname,e.fro, e.to)
new_relaxation = TemporalRelaxation(e)
if vname.find("vlr") != -1:
new_relaxation.relaxed_lb = self.l[(e.fro,e.to)].getValue()
else:
new_relaxation.relaxed_ub = self.u[(e.fro, e.to)].getValue()
if var_a.getAttr("X") > 0:
solution.add_temporal_relaxation(new_relaxation)
# for e in self.network.temporal_constraints.values():
# if e.activated:
# print(e.fro, e.to, self.l[(e.fro, e.to)].getValue(), self.u[(e.fro, e.to)].getValue())
solution.utility = round(m.getObjective().getValue(), 6)
if solution.utility > 1000 and self.objective_type == ObjectiveType.MAX_FLEX_UNCERTAINTY:
solution.utility = 1000
# for node_a in range(1, self.num_nodes+1):
# for node_b in range(1, self.num_nodes+1):
# if node_a != node_b:
# f.write("%s->%s [%s, %s]\n"%(node_a,node_b,self.l[(node_a,node_b)].getValue(), self.u[(node_a,node_b)].getValue() ))
# # if solution.utility > 100:
# solution.utility = 100
# f.close()
#print a dot file
# f = open('sol.dot', 'w')
# f.write('digraph G {\n nodesep = .45; \n size = 30;\n label="CCTP";\n')
#
# for e in self.network.temporal_constraints.values():
# if e.activated:
# f.write('"%s"->"%s"'%(e.fro, e.to))
# tlb = self.l[(e.fro, e.to)].getValue()
# tub = self.u[(e.fro, e.to)].getValue()
# f.write('[ label = "[%s,%s]'%(tlb, tub))
# if not e.controllable:
# f.write(' type=dashed')
# f.write('"];\n')
# #%d"];'%(e.fro, e.to,e.get_lower_bound(),e.get_upper_bound(),e.controllable))
# f.write("}")
# f.close()
return solution
