From d95ba652abbbfda10f29ca8b80c2126825a65eeb Mon Sep 17 00:00:00 2001
From: Johannes Singler <singler@kit.edu>
Date: Thu, 19 Nov 2009 16:43:20 +0000
Subject: [PATCH] partition.h (__parallel_partition): Correctly initialize
chunk size.
2009-11-19 Johannes Singler <singler@kit.edu>
* include/parallel/partition.h (__parallel_partition): Correctly
initialize chunk size.
(__parallel_nth_element): Respect nth_element_minimal_n. Use
sequential nth_element as base case, instead of sequential sort.
From-SVN: r154333
---
libstdc++-v3/ChangeLog | 7 +++++++
libstdc++-v3/include/parallel/partition.h | 11 ++++++-----
2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 76caa592846e..db8246e199d7 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2009-11-19 Johannes Singler <singler@kit.edu>
+
+ * include/parallel/partition.h (__parallel_partition): Correctly
+ initialize chunk size.
+ (__parallel_nth_element): Respect nth_element_minimal_n. Use
+ sequential nth_element as base case, instead of sequential sort.
+
2009-11-17 Benjamin Kosnik <bkoz@redhat.com>
* include/profile/impl/profiler.h: Remove namespace markup.
diff --git a/libstdc++-v3/include/parallel/partition.h b/libstdc++-v3/include/parallel/partition.h
index cfc2fd3737e9..52993c86c957 100644
--- a/libstdc++-v3/include/parallel/partition.h
+++ b/libstdc++-v3/include/parallel/partition.h
@@ -73,7 +73,7 @@ namespace __gnu_parallel
bool* __reserved_left = NULL, * __reserved_right = NULL;
- _DifferenceType __chunk_size;
+ _DifferenceType __chunk_size = __s.partition_chunk_size;
omp_lock_t __result_lock;
omp_init_lock(&__result_lock);
@@ -345,15 +345,16 @@ namespace __gnu_parallel
_RAIter __split;
_RandomNumber __rng;
- _DifferenceType __minimum_length =
- std::max<_DifferenceType>(2, _Settings::get().partition_minimal_n);
+ const _Settings& __s = _Settings::get();
+ _DifferenceType __minimum_length = std::max<_DifferenceType>(2,
+ std::max(__s.nth_element_minimal_n, __s.partition_minimal_n));
// Break if input range to small.
while (static_cast<_SequenceIndex>(__end - __begin) >= __minimum_length)
{
_DifferenceType __n = __end - __begin;
- _RAIter __pivot_pos = __begin + __rng(__n);
+ _RAIter __pivot_pos = __begin + __rng(__n);
// Swap __pivot_pos value to end.
if (__pivot_pos != (__end - 1))
@@ -412,7 +413,7 @@ namespace __gnu_parallel
}
// Only at most _Settings::partition_minimal_n __elements __left.
- __gnu_sequential::sort(__begin, __end, __comp);
+ __gnu_sequential::nth_element(__begin, __nth, __end, __comp);
}
/** @brief Parallel implementation of std::partial_sort().
--
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