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InternalSolver: Better specify and test infeasibility

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This commit is contained in:
Alinson S. Xavier
2021-01-21 09:15:14 -06:00
parent 05497cab07
commit 6890840c6d
9 changed files with 134 additions and 65 deletions
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28
miplearn/solvers/gurobi.py
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@@ -128,8 +128,11 @@ class GurobiSolver(InternalSolver):
for (idx, var) in vardict.items():
var.vtype = self.GRB.BINARY
log = streams[0].getvalue()
opt_value = None
if not self.is_infeasible():
opt_value = self.model.objVal
return {
"Optimal value": self.model.objVal,
"Optimal value": opt_value,
"Log": log,
}
@@ -173,14 +176,15 @@ class GurobiSolver(InternalSolver):
if not should_repeat:
break
log = streams[0].getvalue()
if self.model.modelSense == 1:
sense = "min"
lb = self.model.objBound
ub = self.model.objVal
else:
sense = "max"
lb = self.model.objVal
ub = self.model.objBound
ub, lb = None, None
sense = "min" if self.model.modelSense == 1 else "max"
if self.model.solCount > 0:
if self.model.modelSense == 1:
lb = self.model.objBound
ub = self.model.objVal
else:
lb = self.model.objVal
ub = self.model.objBound
ws_value = self._extract_warm_start_value(log)
stats: MIPSolveStats = {
"Lower bound": lb,
@@ -194,8 +198,10 @@ class GurobiSolver(InternalSolver):
}
return stats
def get_solution(self) -> Dict:
def get_solution(self) -> Optional[Dict]:
self._raise_if_callback()
if self.model.solCount == 0:
return None
solution: Dict = {}
for (varname, vardict) in self._all_vars.items():
solution[varname] = {}
@@ -228,7 +234,7 @@ class GurobiSolver(InternalSolver):
var = self._all_vars[var_name][index]
return self._get_value(var)
def is_infeasible(self):
def is_infeasible(self) -> bool:
return self.model.status in [self.GRB.INFEASIBLE, self.GRB.INF_OR_UNBD]
def get_dual(self, cid):