Reformat source code with Black; add pre-commit hooks and CI checks

miplearn/solvers/gurobi.py

@@ -13,10 +13,11 @@ logger = logging.getLogger(__name__)
 
 
 class GurobiSolver(InternalSolver):
-    def __init__(self,
-                 params=None,
-                 lazy_cb_frequency=1,
-                 ):
+    def __init__(
+        self,
+        params=None,
+        lazy_cb_frequency=1,
+    ):
         """
         An InternalSolver backed by Gurobi's Python API (without Pyomo).
 
@@ -33,6 +34,7 @@ class GurobiSolver(InternalSolver):
         if params is None:
             params = {}
         from gurobipy import GRB
+
         self.GRB = GRB
         self.instance = None
         self.model = None
@@ -44,8 +46,7 @@ class GurobiSolver(InternalSolver):
         if lazy_cb_frequency == 1:
             self.lazy_cb_where = [self.GRB.Callback.MIPSOL]
         else:
-            self.lazy_cb_where = [self.GRB.Callback.MIPSOL,
-                                  self.GRB.Callback.MIPNODE]
+            self.lazy_cb_where = [self.GRB.Callback.MIPSOL, self.GRB.Callback.MIPNODE]
 
     def set_instance(self, instance, model=None):
         self._raise_if_callback()
@@ -70,14 +71,15 @@ class GurobiSolver(InternalSolver):
                 idx = [0]
             else:
                 name = m.group(1)
-                idx = tuple(int(k) if k.isdecimal() else k
-                            for k in m.group(2).split(","))
+                idx = tuple(
+                    int(k) if k.isdecimal() else k for k in m.group(2).split(",")
+                )
             if len(idx) == 1:
                 idx = idx[0]
             if name not in self._all_vars:
                 self._all_vars[name] = {}
             self._all_vars[name][idx] = var
-            if var.vtype != 'C':
+            if var.vtype != "C":
                 if name not in self._bin_vars:
                     self._bin_vars[name] = {}
                 self._bin_vars[name][idx] = var
@@ -103,15 +105,9 @@ class GurobiSolver(InternalSolver):
             for (idx, var) in vardict.items():
                 var.vtype = self.GRB.BINARY
         log = streams[0].getvalue()
-        return {
-            "Optimal value": self.model.objVal,
-            "Log": log
-        }
+        return {"Optimal value": self.model.objVal, "Log": log}
 
-    def solve(self,
-              tee=False,
-              iteration_cb=None,
-              lazy_cb=None):
+    def solve(self, tee=False, iteration_cb=None, lazy_cb=None):
         self._raise_if_callback()
 
         def cb_wrapper(cb_model, cb_where):
@@ -133,7 +129,7 @@ class GurobiSolver(InternalSolver):
         if tee:
             streams += [sys.stdout]
         if iteration_cb is None:
-            iteration_cb = lambda : False
+            iteration_cb = lambda: False
         while True:
             logger.debug("Solving MIP...")
             with RedirectOutput(streams):
@@ -187,7 +183,9 @@ class GurobiSolver(InternalSolver):
         elif self.cb_where is None:
             return var.x
         else:
-            raise Exception("get_value cannot be called from cb_where=%s" % self.cb_where)
+            raise Exception(
+                "get_value cannot be called from cb_where=%s" % self.cb_where
+            )
 
     def get_variables(self):
         self._raise_if_callback()
@@ -220,8 +218,10 @@ class GurobiSolver(InternalSolver):
                 if value is not None:
                     count_fixed += 1
                     self._all_vars[varname][idx].start = value
-        logger.info("Setting start values for %d variables (out of %d)" %
-                    (count_fixed, count_total))
+        logger.info(
+            "Setting start values for %d variables (out of %d)"
+            % (count_fixed, count_total)
+        )
 
     def clear_warm_start(self):
         self._raise_if_callback()
@@ -248,10 +248,7 @@ class GurobiSolver(InternalSolver):
     def extract_constraint(self, cid):
         self._raise_if_callback()
         constr = self.model.getConstrByName(cid)
-        cobj = (self.model.getRow(constr),
-                constr.sense,
-                constr.RHS,
-                constr.ConstrName)
+        cobj = (self.model.getRow(constr), constr.sense, constr.RHS, constr.ConstrName)
         self.model.remove(constr)
         return cobj
 
@@ -316,7 +313,7 @@ class GurobiSolver(InternalSolver):
             value = matches[0]
         return value
 
-    def __getstate__(self):     
+    def __getstate__(self):
         return {
             "params": self.params,
             "lazy_cb_where": self.lazy_cb_where,
@@ -324,6 +321,7 @@ class GurobiSolver(InternalSolver):
 
     def __setstate__(self, state):
         from gurobipy import GRB
+
         self.params = state["params"]
         self.lazy_cb_where = state["lazy_cb_where"]
         self.GRB = GRB
@@ -331,4 +329,4 @@ class GurobiSolver(InternalSolver):
         self.model = None
         self._all_vars = None
         self._bin_vars = None
-        self.cb_where = None        
+        self.cb_where = None