pystencils/backends/cbackend.py

@@ -391,6 +391,8 @@ class CustomSympyPrinter(CCodePrinter):
             if isinstance(arg, sp.Number) and arg.is_finite:
                 return self._typed_number(arg, data_type)
             else:
+                if str(arg) == "-1":
+                    print("!!")
                 return "((%s)(%s))" % (data_type, self._print(arg))
         elif isinstance(expr, fast_division):
             return "({})".format(self._print(expr.args[0] / expr.args[1]))

pystencils/data_types.py

@@ -550,7 +550,7 @@ def get_type_of_expression(expr,
         return result
     elif isinstance(expr, sp.Pow):
         base_type = get_type(expr.args[0])
-        if expr.exp.is_integer:
+        if expr.exp.is_integer or expr.exp == sp.Rational(1, 2):
             return base_type
         else:
             return collate_types([create_type(default_float_type), base_type])