From 8bb0ce460498e595eb9202fa0e4ae763eeae7ffe Mon Sep 17 00:00:00 2001
From: Stephan Seitz <stephan.seitz@fau.de>
Date: Mon, 30 Dec 2019 13:54:08 +0100
Subject: [PATCH] Throw error when trying to sympify `pystencils.Field` (e.g.
using it in an Assignment without indexing)
---
pystencils/field.py | 8 +++++++-
pystencils_tests/test_assignment_collection.py | 14 ++++++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/pystencils/field.py b/pystencils/field.py
index 507be0c2..a8c82b47 100644
--- a/pystencils/field.py
+++ b/pystencils/field.py
@@ -15,7 +15,7 @@ import pystencils
from pystencils.alignedarray import aligned_empty
from pystencils.data_types import StructType, TypedSymbol, create_type
from pystencils.kernelparameters import FieldShapeSymbol, FieldStrideSymbol
-from pystencils.stencil import direction_string_to_offset, offset_to_direction_string, inverse_direction
+from pystencils.stencil import direction_string_to_offset, inverse_direction, offset_to_direction_string
from pystencils.sympyextensions import is_integer_sequence
__all__ = ['Field', 'fields', 'FieldType', 'AbstractField']
@@ -413,6 +413,12 @@ class Field(AbstractField):
def __str__(self):
return self.name
+ def __getattribute__(self, name):
+ if name == '__sympy__':
+ raise RuntimeError("pystencils.Field cannot by sympified!\n"
+ "Please use a proper indexing to access elements of the Field!")
+ return super().__getattribute__(name)
+
def neighbor(self, coord_id, offset):
offset_list = [0] * self.spatial_dimensions
offset_list[coord_id] = offset
diff --git a/pystencils_tests/test_assignment_collection.py b/pystencils_tests/test_assignment_collection.py
index 42e3791a..cbe08763 100644
--- a/pystencils_tests/test_assignment_collection.py
+++ b/pystencils_tests/test_assignment_collection.py
@@ -1,4 +1,6 @@
+import pytest
import sympy as sp
+import pystencils
from pystencils import Assignment, AssignmentCollection
from pystencils.astnodes import Conditional
@@ -40,3 +42,15 @@ def test_free_and_defined_symbols():
print(ac)
print(ac.__repr__)
+
+
+def test_sympifying_fields():
+ x, y = pystencils.fields('x, y: double[1d]')
+ # Apparently, we trigger our helpful error message only for Sympy>=1.5
+ with pytest.raises((RuntimeError, sp.SympifyError)):
+ AssignmentCollection({
+ x: y
+ })
+
+ with pytest.raises((RuntimeError, sp.SympifyError)):
+ sp.S(x)
--
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