only decompose if has_nested

cpmpy/expressions/core.py

@@ -135,9 +135,6 @@ def __repr__(self):
     def __hash__(self):
         return hash(self.__repr__())
 
-    def has_nested(self):
-        return not all([is_leaf(x) for x in self.args])
-
     def is_leaf(self):
         return False  # default
 

cpmpy/expressions/utils.py

@@ -129,7 +129,16 @@ def argval(a):
 
 
 def is_leaf(a):
-    return a.is_leaf() if hasattr(a, 'is_leaf') else True
+    if hasattr(a, 'is_leaf'):
+        return a.is_leaf()
+    if is_any_list(a):
+        return all([is_leaf(x) for x in a])
+    else:
+        return True
+
+
+def has_nested(expr):
+    return not all([is_leaf(x) for x in expr.args])
 
 
 def eval_comparison(str_op, lhs, rhs):

cpmpy/transformations/decompose_global.py

@@ -6,7 +6,7 @@
 from ..expressions.globalfunctions import GlobalFunction
 from ..expressions.core import Expression, Comparison, Operator, BoolVal
 from ..expressions.variables import _BoolVarImpl, intvar, boolvar, _NumVarImpl, cpm_array, NDVarArray
-from ..expressions.utils import is_any_list, eval_comparison
+from ..expressions.utils import is_any_list, eval_comparison, has_nested
 from ..expressions.python_builtins import all
 from .flatten_model import flatten_constraint, normalized_numexpr
 
@@ -37,8 +37,9 @@ def decompose_in_tree(lst_of_expr, supported=set(), supported_reified=set(), _to
 
     newlist = []  # decomposed constraints will go here
     for expr in lst_of_expr:
-
-        if is_any_list(expr):
+        if not has_nested(expr):
+            newlist.append(expr)
+        elif is_any_list(expr):
             assert nested is True, "Cannot have nested lists without passing trough an expression, make sure to run cpmpy.transformations.normalize.toplevel_list first."
             newexpr = decompose_in_tree(expr, supported, supported_reified, _toplevel, nested=True)
             if isinstance(expr, NDVarArray):