double check shape when making aux vars

Author: IgnaceBleukx

cpmpy/expressions/globalconstraints.py

@@ -868,6 +868,9 @@ def decompose(self):
         """
         X, Y = cpm_array(self.args)
 
+        if len(X) == 0 == len(Y):
+            return [cp.BoolVal(False)], [] # based on the decomp, it's false...
+
         bvar = boolvar(shape=(len(X) + 1))
 
         # Constraint ensuring that each element in X is less than or equal to the corresponding element in Y,
@@ -914,6 +917,9 @@ def decompose(self):
         """
         X, Y = cpm_array(self.args)
 
+        if len(X) == 0 == len(Y):
+            return [cp.BoolVal(False)], [] # based on the decomp, it's false...
+
         bvar = boolvar(shape=(len(X) + 1))
         defining = [bvar == ((X <= Y) & ((X < Y) | bvar[1:]))]
         defining.append(bvar[-1] == (X[-1] <= Y[-1]))

cpmpy/expressions/globalfunctions.py

@@ -395,7 +395,7 @@ def decompose_comparison(self, cmp_op, cpm_rhs):
         constraints = []
 
         # introduce boolvar for each possible value
-        bvars = boolvar(shape=(ub+1-lb))
+        bvars = boolvar(shape=(ub+1-lb,))
 
         args = cpm_array(self.args)
         # bvar is true if the value is taken by any variable