Fix removal of variables

Author: sebheger

mip/lists.py

@@ -69,9 +69,9 @@ def remove(self: "VarList", vars: List["mip.Var"]):
         i = 0
         for v in self.__vars:
             if iv[v.idx] == 0:
-                v.idx = -1
+                v._idx = -1
             else:
-                v.idx = i
+                v._idx = i
                 i += 1
         self.__vars = [v for v in self.__vars if v.idx != -1]
 

test/test_model.py

@@ -1313,4 +1313,4 @@ def test_remove(solver):
         m.remove([None])
 
     m.remove(constr)
-    # TODO: Test the removal of variables (currently failing, see https://github.com/coin-or/python-mip/pull/288#discussion_r919215654)
+    m.remove(x)