From b47bdf9d6c35defd38ecb40f506c286ffbe8b17a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20Kl=C3=B6ckner?= <inform@tiker.net>
Date: Mon, 12 Dec 2016 16:28:02 -0500
Subject: [PATCH] Revert "Merge branch 'remove-ambigiuous-scheduling-warning'
into 'master'"
This reverts merge request !62
---
doc/tutorial.rst | 13 +++++++++----
loopy/schedule/__init__.py | 26 +++++++++++++++++++++++---
2 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/doc/tutorial.rst b/doc/tutorial.rst
index 9e4bd8c91..d9627deed 100644
--- a/doc/tutorial.rst
+++ b/doc/tutorial.rst
@@ -456,8 +456,8 @@ control is the nesting of loops. For example, should the *i* loop be nested
around the *j* loop, or the other way around, in the following simple
zero-fill kernel?
-It turns out that Loopy will choose a loop nesting for us, but it might be
-ambiguous. Consider the following code:
+It turns out that Loopy will typically choose a loop nesting for us, but it
+does not like doing so. Loo.py will react to the following code
.. doctest::
@@ -467,8 +467,13 @@ ambiguous. Consider the following code:
... a[i,j] = 0
... """)
-Both nestings of the inames `i` and `j` result in a correct kernel.
-This ambiguity can be resolved:
+By saying::
+
+ LoopyWarning: kernel scheduling was ambiguous--more than one schedule found, ignoring
+
+And by picking one of the possible loop orderings at random.
+
+The warning (and the nondeterminism it warns about) is easily resolved:
.. doctest::
diff --git a/loopy/schedule/__init__.py b/loopy/schedule/__init__.py
index bf51147b5..e23e5f350 100644
--- a/loopy/schedule/__init__.py
+++ b/loopy/schedule/__init__.py
@@ -1959,7 +1959,7 @@ def get_one_scheduled_kernel(kernel):
if CACHING_ENABLED:
try:
- result = schedule_cache[sched_cache_key]
+ result, ambiguous = schedule_cache[sched_cache_key]
logger.debug("%s: schedule cache hit" % kernel.name)
from_cache = True
@@ -1967,18 +1967,38 @@ def get_one_scheduled_kernel(kernel):
pass
if not from_cache:
+ ambiguous = False
+
+ kernel_count = 0
+
from time import time
start_time = time()
logger.info("%s: schedule start" % kernel.name)
- result = next(iter(generate_loop_schedules(kernel)))
+ for scheduled_kernel in generate_loop_schedules(kernel):
+ kernel_count += 1
+
+ if kernel_count == 1:
+ # use the first schedule
+ result = scheduled_kernel
+
+ if kernel_count == 2:
+ ambiguous = True
+ break
logger.info("%s: scheduling done after %.2f s" % (
kernel.name, time()-start_time))
+ if ambiguous:
+ from warnings import warn
+ from loopy.diagnostic import LoopyWarning
+ warn("scheduling for kernel '%s' was ambiguous--more than one "
+ "schedule found, ignoring" % kernel.name, LoopyWarning,
+ stacklevel=2)
+
if CACHING_ENABLED and not from_cache:
- schedule_cache[sched_cache_key] = result
+ schedule_cache[sched_cache_key] = result, ambiguous
return result
--
GitLab