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* [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister
@ 2012-11-05 16:14 wgh at beyondunreal dot com
2012-11-05 16:15 ` [Bug libstdc++/55215] " wgh at beyondunreal dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: wgh at beyondunreal dot com @ 2012-11-05 16:14 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215
Bug #: 55215
Summary: Constructor seeding is broken for Mersenne twister
Classification: Unclassified
Product: gcc
Version: 4.6.4
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: wgh@beyondunreal.com
http://ideone.com/p8B7lF (the code is also provided in attachment).
I expected that both functions, f and g, would return the same value every
time. But, as we can see, initializing Mersenne using its constructor doesn't
yield consistent results.
I tested compiler from Visual Studio 2012, and it doesn't have this bug. Other
random number engines probably don't have this bug (I tested std::minstd_rand).
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/55215] Constructor seeding is broken for Mersenne twister 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com @ 2012-11-05 16:15 ` wgh at beyondunreal dot com 2012-11-05 17:44 ` paolo.carlini at oracle dot com ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: wgh at beyondunreal dot com @ 2012-11-05 16:15 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215 --- Comment #1 from wgh at beyondunreal dot com 2012-11-05 16:15:06 UTC --- Created attachment 28619 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28619 reproduction ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/55215] Constructor seeding is broken for Mersenne twister 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com 2012-11-05 16:15 ` [Bug libstdc++/55215] " wgh at beyondunreal dot com @ 2012-11-05 17:44 ` paolo.carlini at oracle dot com 2012-11-05 19:25 ` paolo at gcc dot gnu.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: paolo.carlini at oracle dot com @ 2012-11-05 17:44 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2012-11-05 AssignedTo|unassigned at gcc dot |paolo.carlini at oracle dot |gnu.org |com Target Milestone|--- |4.7.3 Ever Confirmed|0 |1 --- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-05 17:44:02 UTC --- It's a stupid uninitialized variable. Will fix momentarily. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/55215] Constructor seeding is broken for Mersenne twister 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com 2012-11-05 16:15 ` [Bug libstdc++/55215] " wgh at beyondunreal dot com 2012-11-05 17:44 ` paolo.carlini at oracle dot com @ 2012-11-05 19:25 ` paolo at gcc dot gnu.org 2012-11-05 20:12 ` paolo.carlini at oracle dot com 2012-11-05 20:12 ` paolo at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: paolo at gcc dot gnu.org @ 2012-11-05 19:25 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215 --- Comment #3 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-11-05 19:25:27 UTC --- Author: paolo Date: Mon Nov 5 19:25:20 2012 New Revision: 193181 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193181 Log: 2012-11-05 Paolo Carlini <paolo.carlini@oracle.com> PR libstdc++/55215 * include/bits/random.tcc (mersenne_twister_engine<>::seed(_Sseq&)): Assign state_size to _M_p. * testsuite/26_numerics/random/mersenne_twister_engine/cons/55215.cc: New. * testsuite/26_numerics/random/independent_bits_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/shuffle_order_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/subtract_with_carry_engine/cons/ 55215.cc: Likewise. * testsuite/26_numerics/random/discard_block_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/linear_congruential_engine/cons/ 55215.cc: Likewise. Added: trunk/libstdc++-v3/testsuite/26_numerics/random/discard_block_engine/cons/55215.cc trunk/libstdc++-v3/testsuite/26_numerics/random/independent_bits_engine/cons/55215.cc trunk/libstdc++-v3/testsuite/26_numerics/random/linear_congruential_engine/cons/55215.cc trunk/libstdc++-v3/testsuite/26_numerics/random/mersenne_twister_engine/cons/55215.cc trunk/libstdc++-v3/testsuite/26_numerics/random/shuffle_order_engine/cons/55215.cc trunk/libstdc++-v3/testsuite/26_numerics/random/subtract_with_carry_engine/cons/55215.cc Modified: trunk/libstdc++-v3/ChangeLog trunk/libstdc++-v3/include/bits/random.tcc ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/55215] Constructor seeding is broken for Mersenne twister 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com ` (2 preceding siblings ...) 2012-11-05 19:25 ` paolo at gcc dot gnu.org @ 2012-11-05 20:12 ` paolo.carlini at oracle dot com 2012-11-05 20:12 ` paolo at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: paolo.carlini at oracle dot com @ 2012-11-05 20:12 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED --- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-05 20:12:42 UTC --- Fixed mainline and 4.7.3. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/55215] Constructor seeding is broken for Mersenne twister 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com ` (3 preceding siblings ...) 2012-11-05 20:12 ` paolo.carlini at oracle dot com @ 2012-11-05 20:12 ` paolo at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: paolo at gcc dot gnu.org @ 2012-11-05 20:12 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55215 --- Comment #4 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-11-05 20:11:44 UTC --- Author: paolo Date: Mon Nov 5 20:11:32 2012 New Revision: 193183 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193183 Log: 2012-11-05 Paolo Carlini <paolo.carlini@oracle.com> PR libstdc++/55215 * include/bits/random.tcc (mersenne_twister_engine<>::seed(_Sseq&)): Assign state_size to _M_p. * testsuite/26_numerics/random/mersenne_twister_engine/cons/55215.cc: New. * testsuite/26_numerics/random/independent_bits_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/shuffle_order_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/subtract_with_carry_engine/cons/ 55215.cc: Likewise. * testsuite/26_numerics/random/discard_block_engine/cons/55215.cc: Likewise. * testsuite/26_numerics/random/linear_congruential_engine/cons/ 55215.cc: Likewise. Added: branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/discard_block_engine/cons/55215.cc branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/independent_bits_engine/cons/55215.cc branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/linear_congruential_engine/cons/55215.cc branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/mersenne_twister_engine/cons/55215.cc branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/shuffle_order_engine/cons/55215.cc branches/gcc-4_7-branch/libstdc++-v3/testsuite/26_numerics/random/subtract_with_carry_engine/cons/55215.cc Modified: branches/gcc-4_7-branch/libstdc++-v3/ChangeLog branches/gcc-4_7-branch/libstdc++-v3/include/bits/random.tcc ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-11-05 20:12 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-11-05 16:14 [Bug libstdc++/55215] New: Constructor seeding is broken for Mersenne twister wgh at beyondunreal dot com 2012-11-05 16:15 ` [Bug libstdc++/55215] " wgh at beyondunreal dot com 2012-11-05 17:44 ` paolo.carlini at oracle dot com 2012-11-05 19:25 ` paolo at gcc dot gnu.org 2012-11-05 20:12 ` paolo.carlini at oracle dot com 2012-11-05 20:12 ` paolo at gcc dot gnu.org
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