Fix remaining tests

Author: hbierlee

cpmpy/solvers/rc2.py

@@ -195,8 +195,6 @@ def solve(self, time_limit=None, stratified=True, adapt=True, exhaust=True, minz
 
         # the user vars are only the Booleans (e.g. to ensure solveAll behaves consistently)
         self.user_vars = get_user_vars(self.user_vars, self.ivarmap)
-        
-        # TODO I believe assumptions can be added in the WCNF as `soft`
 
         # TODO: set time limit
         if time_limit is not None:
@@ -284,19 +282,17 @@ def transform_objective(self, expr):
         else:
             raise NotImplementedError(f"CPM_rc2: Non supported objective {flat_obj} (yet?)")
 
-        try:
-            terms, cons, k = _encode_lin_expr(self.ivarmap, xs, weights, self.encoding)
-        except TypeError:
-            raise NotImplementedError(f"CPM_rc2: Unsupported objective: {flat_obj}")
+        terms, cons, k = _encode_lin_expr(self.ivarmap, xs, weights, self.encoding)
 
         self += cons
         const += k
 
+        terms = [(w, x) for w,x in terms if w != 0]  # positive coefficients only
         ws, xs = zip(*terms)  # unzip
-        new_weights, new_xs, k = only_positive_coefficients_(ws, xs)
+        new_weights, new_xs, k = only_positive_coefficients_(ws, xs) # this is actually only_non_negative_coefficients
         const += k
 
-        return new_weights, new_xs, const
+        return list(new_weights), list(new_xs), const
 
 
     def objective(self, expr, minimize):

cpmpy/transformations/int2bool.py

@@ -10,6 +10,7 @@
 from ..expressions.core import BoolVal, Comparison, Expression, Operator
 from ..expressions.globalconstraints import DirectConstraint
 from ..expressions.variables import _BoolVarImpl, _IntVarImpl, boolvar
+from ..expressions.utils import is_int
 
 UNKNOWN_COMPARATOR_ERROR = ValueError("Comparator is not known or should have been simplified by linearize.")
 EMPTY_DOMAIN_ERROR = ValueError("Attempted to encode variable with empty domain (which is unsat)")
@@ -101,7 +102,9 @@ def _encode_lin_expr(ivarmap, xs, weights, encoding, cmp=None):
     k = 0
     for w, x in zip(weights, xs):
         # the linear may contain Boolean as well as integer variables
-        if isinstance(x, _BoolVarImpl):
+        if is_int(x):
+            k += w * x
+        elif isinstance(x, _BoolVarImpl):
             terms += [(w, x)]
         elif isinstance(x, _IntVarImpl):
             x_enc, x_cons = _encode_int_var(ivarmap, x, _decide_encoding(x, cmp, encoding))
@@ -111,7 +114,7 @@ def _encode_lin_expr(ivarmap, xs, weights, encoding, cmp=None):
             terms += new_terms
             k += k_
         else:
-            raise TypeError
+            raise TypeError(f"Term {w} * {x} for {type(x)}")
     return terms, domain_constraints, k
 
 

cpmpy/transformations/linearize.py

@@ -631,6 +631,7 @@ def canonical_comparison(lst_of_expr):
     return newlist
 
 def only_positive_coefficients_(ws, xs):
+    """ Helper function which weight """
     indices = {i for i, (w, x) in enumerate(zip(ws, xs)) if w < 0 and isinstance(x, _BoolVarImpl)}
     nw, na = zip(*[(-w, ~x) if i in indices else (w, x) for i, (w, x) in enumerate(zip(ws, xs))])
     cons = sum(ws[i] for i in indices)
@@ -645,6 +646,7 @@ def only_positive_coefficients(lst_of_expr):
 
         Resulting expression is linear.
     """
+    # TODO this should be renamed to only_non_negative_coefficients, because it does not remove terms with coefficient 0. I think it does not, because it risks removing user variables.
     newlist = []
     for cpm_expr in lst_of_expr:
         if isinstance(cpm_expr, Comparison):

tests/test_rc2_obj.py

@@ -182,7 +182,8 @@ def test_rc2_solve_with_integer_variables(self):
         model = cp.Model()
         x = cp.boolvar(2)
         y = cp.intvar(0, 3, shape=2)
-        model.maximize(cp.sum(x) + cp.sum(y))
+        z = cp.intvar(0, 3)
+        model.maximize(cp.sum(x) + cp.sum(y) + 0 * z)
         # Add constraints
         model += (x[0] != x[1])  # both must be different
         model += (y[0] < y[1])  # y[0] must be less than y[1]