From 6b857cff20bef3ed3c5ab22c20eeafe5608e3556 Mon Sep 17 00:00:00 2001
From: Stephan Seitz <stephan.seitz@fau.de>
Date: Wed, 7 Aug 2019 12:36:24 +0200
Subject: [PATCH] Use own implementation of _has_exclusive_writes
AssignmentCollection.has_exclusive_writes was not merged in pystencils core
since the check overlaps with pystencils own checks and is very specific
---
src/pystencils_autodiff/autodiff.py | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/src/pystencils_autodiff/autodiff.py b/src/pystencils_autodiff/autodiff.py
index 984eaaf..9447df9 100644
--- a/src/pystencils_autodiff/autodiff.py
+++ b/src/pystencils_autodiff/autodiff.py
@@ -20,6 +20,27 @@ class DiffModes(str, Enum):
TF_MAD = 'transposed-forward'
+def _has_exclusive_writes(assignment_collection):
+ """
+ Simple check for exclusive (non-overlapping) writes.
+ I.e. AssignmentCollection can be executed safely in parallel without caring about race conditions.
+ No writes on same spatial location (considering all possible shifts).
+ """
+
+ assignments = assignment_collection.main_assignments
+ write_field_accesses = [a.lhs for a in assignments if isinstance(a.lhs, ps.Field.Access)]
+
+ exclusive_writes = set()
+ for a in write_field_accesses:
+
+ if (a.field, a.index) in exclusive_writes:
+ return False
+ else:
+ exclusive_writes.add((a.field, a.index))
+
+ return True
+
+
def get_jacobian_of_assignments(assignments, diff_variables):
"""
Calculates the Jacobian of iterable of assignments wrt. diff_variables
@@ -180,7 +201,7 @@ Backward:
main_assignments = [a for a in backward_assignments if isinstance(a.lhs, ps.Field.Access)]
subexpressions = [a for a in backward_assignments if not isinstance(a.lhs, ps.Field.Access)]
backward_assignments = ps.AssignmentCollection(main_assignments, subexpressions)
- assert backward_assignments.has_exclusive_writes, "Backward assignments don't have exclusive writes." + \
+ assert _has_exclusive_writes(backward_assignments), "Backward assignments don't have exclusive writes." + \
" You should consider using 'transposed-forward' mode for resolving those conflicts"
self._forward_assignments = forward_assignments
@@ -329,7 +350,7 @@ Backward:
subexpressions = [a for a in backward_assignments if not isinstance(a.lhs, ps.Field.Access)]
backward_assignments = ps.AssignmentCollection(main_assignments, subexpressions)
- assert backward_assignments.has_exclusive_writes, "Backward assignments don't have exclusive writes!"
+ assert _has_exclusive_writes(backward_assignments), "Backward assignments don't have exclusive writes!"
self._backward_assignments = backward_assignments
self._backward_field_map = {**diff_read_fields, **diff_write_fields}
--
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