Fix identification of interger type in abs functions

pystencils/backends/cbackend.py

@@ -362,7 +362,7 @@ class CustomSympyPrinter(CCodePrinter):
         return result.replace("\n", "")
 
     def _print_Abs(self, expr):
-        if expr.is_integer:
+        if expr.args[0].is_integer:
             return 'abs({0})'.format(self._print(expr.args[0]))
         else:
             return 'fabs({0})'.format(self._print(expr.args[0]))

pystencils_tests/test_abs.py

+import sympy
+
+import pystencils
+from pystencils.data_types import cast_func, create_type
+
+
+def test_abs():
+    x, y, z = pystencils.fields('x, y, z:  float64[2d]')
+
+    default_int_type = create_type('int64')
+
+    assignments = pystencils.AssignmentCollection({
+        x[0, 0]: sympy.Abs(cast_func(y[0, 0], default_int_type))
+    })
+
+    ast = pystencils.create_kernel(assignments, target="gpu")
+    code = pystencils.get_code_str(ast)
+    print(code)
+    assert 'fabs(' not in code