April 2014 - Boost - lists.boost.org

[serialization] proposed improvements: forward-compatibility of serialization
by Andrzej Horoszczak 08 Apr '14

08 Apr '14

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phoenix bind vs boost bind?
by Robert Dailey 07 Apr '14

07 Apr '14

First of all, I'm using boost 1.55.0 on MSVC9. I've been using boost::phoenix in various places in my code base for easier usage of std::for_each and friends. However, I do not create lazy functions for a lot of the functions I bind to because they are only needed in one place most of the time. As a result, I use boost::phoenix::bind the same as I'd use boost::bind(). However I have read in various places that boost::bind is being deprecated. I'm not sure if there is truth to this, but is there a reason to choose one over the other? Is phx::bind() basically an "upgrade" to boost::bind? If I intermingle them, I have a lot of issues out of placeholder ambiguities that results in more boilerplate code (i.e. using boost::phoenix::placeholders::_1 everywhere). Any tips? I haven't used boost in a few years so I just want to make sure I'm not using it incorrectly. Thanks in advance.

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Re: [boost] [container] Vector-like container, which takes, feedback for Jeremy M.
by Alexander Kuprijanov 07 Apr '14

07 Apr '14

> Message: 3 > Date: Sun, 6 Apr 2014 09:59:20 +1000 > From: Jeremy Murphy <jeremy.william.murphy(a)gmail.com> > On 6 April 2014 00:45, Alexander Kuprijanov <alexkupri(a)gmail.com> wrote: > >> Hi, everybody! >> The most important feature of my container is performance. However, other >> features will appear later. >> https://github.com/alexkupri/array/blob/master/description/description.txt >> Today I compared my container with rope. My container outperformed it 10 >> times. > > > Hi Alex, > > could you include a build file (I recommend CMake)? My cursory attempt to > compile main.cpp spewed lots of errors. Thanks, cheers. > > Jeremy > Hi, Jeremy! Well, I provided makefiles, but I'm not sure if they help. The line: g++ -O3 main.cpp worked well. If you still have problems, be specific and tell, which project (trunk or performance), which errors and which system. "trunk" should be compiled, because I checked it on Linux and Windows; performance is more platform specific and uses __gnu_cxx::rope. Best regards, A.K.

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Network change of the Boost main web/mail server (wowbagger)
by Kim, DongInn 07 Apr '14

07 Apr '14

Dear All, The boost server machine (wowbagger.crest.iu.edu) is requested to change its subnet and I am planning to switch its IP address for the change of the subnet. I have arranged the schedule to update the DNS information of the following hostnames in wowbagger. - www.boost.org - svn.boost.org - lists.boost.org - boostcon.boost.org - beta.boost.org - www.boostcon.org - wiki.boost.org The IP transition date and time: April 07, 2014 6:00am-7:00am Pacific US time 7:00am-8:00am Mountain US time 8:00am-9:00am Central US time 9:00am-10:00am Eastern US time 1:00pm-2:00pm GMT The list of services that may not be available: - Web services: www.boost.org svn.boost.org lists.boost.org ... - Mail services including mailing lists: boost(a)lists.boost.org boost-users(a)lists.boost.org … - Subversion svn.boost.org The old IP address: 129.79.13.33 The new IP address: 129.79.39.203 I have already prepared the IP transition on wowbagger to make the new IP address provide the same services on it so that I hope that there is no actual outage of the services other than the rebooting time. If you happened to use the IP address on your cronjob or programs, please make sure that you switch it with the new one. IMPORTANT ========================================= wowbagger will need to reboot to kick in a new kernel and mount the NFS space with the new IP address at the same time. ========================================== Please let me know if you have any questions or concerns about this IP transition. Regards, -- - DongInn

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[spirit][testing] ICE in gcc 4.8.2 in tests
by Andrey Semashev 07 Apr '14

07 Apr '14

Hi, I'm seeing ICE in a test on BP x86_64 C++11: http://www.boost.org/development/tests/develop/developer/output/BP%20x86_64… This seems to be happening only in develop. I cannot reproduce this with my local gcc 4.8.1. Does anyone know what could be the problem?

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[integer] Is BOOST_HAS_INTPTR_T documentation missing?
by Mostafa 06 Apr '14

06 Apr '14

Is BOOST_HAS_INTPTR_T documentation missing in Boost.Integer?

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[containers] Vector-like container, which takes O(log(N)) > for insert/erase, question to Adam Wulkiewicz about iterators
by Alexander Kuprijanov 06 Apr '14

06 Apr '14

Hi, again, Adam! > > Date: Sat, 05 Apr 2014 16:59:18 +0200 > From: Adam Wulkiewicz <adam.wulkiewicz(a)gmail.com> > And I strongly dissagree with the statement that your container should > be the first choice. std::vector<> will outperform it in most of the > real-life use-cases. Vector outperforms it only (roughly) 2 times on small arrays (when it contains only one leaf) on all operations, only (roughly) 3 times on iterating access on all sizes and only log(N) times on random access. But it severely (N/log(N)) outperforms vector in all insert/erase cases. See my explained test results. I still believe it's close to first choise. > Also, IMHO the most important feature of std::list<> is insert() and > erase() not invalidating other iterators. AFAIU in your container > iterators may be invalid after insert()? That is very interesting question. Currently such sort of persistent iterators (I call them bookmarks) are not implemented. PLEASE PLEASE PLEASE, EVERYBODY, give me an example of the task when such iterators are necessary. Will this feature add feature to my container, if implemented? Best regards, A.K.

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[container] Vector-like container, which takes O(log(N)) for insert/erase, response to Adam Wulkiewicz about performance
by Alexander Kuprijanov 06 Apr '14

06 Apr '14

Hi, Adam! > Date: Sat, 05 Apr 2014 16:59:18 +0200 > From: Adam Wulkiewicz <adam.wulkiewicz(a)gmail.com> > Again, the times you measure are too small to reasonably tell which one > is faster. You could perform each test 10k more times to keep the > results around 1s. I believe my calculations are reliable. I'm sorry I did not explained it earlier and did not provide clarification on github. Firstly, the output is time per one operations in milliseconds. E.g., if it says 1.00e-4, it means 1e-7 seconds or 0. 000 000 1 seconds per one operation. The operation performed many times and result is divided. Secondly, in each operation there are many calculations, by both repeating and array growing. If the line before array says "averaged on 500 measurements" and in array size is 1024, it meant that it was 500 arrays and each of them growed from 512 elements to 1024 elements, giving 256000 atomic additions. Each of them took 1.17e-04 ms in average, they all took about 30 ms. Granularity of Linux timer (which is used in test) is 1 ms, so tolerance in the case is 3%. > Instead of comparing it with a different implementation I guess it would > be sufficient to contain only 2 children in the internal nodes. > Well, I in fact found that numbers 14/28 are near optimum. (There are several optimums for different operations.) Theory agrees with practice, the best performance is when leaf/branch fits one cache line. (In fact, my container allows minimum L=4 M=4, each branch and leaf may have from 2 to 4 items. It behaves worse generally.) I tried to compare it with rope because I was asked to do so. I'll compare it with other similar containers as well. Rope has other problems such as balancing when critical and so on. Best regards, A.K.

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Proposal: Vector-like container, which takes O(log(N)) for insert/erase, response to Bjorn Reese about copy-on-write
by Alexander Kuprijanov 06 Apr '14

06 Apr '14

> Date: Fri, 04 Apr 2014 19:24:53 +0200 > From: Bjorn Reese <breese(a)mail1.stofanet.dk> > To: boost(a)lists.boost.org > Subject: Re: [boost] Proposal: Vector-like container, which takes > O(log(N)) for insert/erase (Glen Fernandes) > Message-ID: <533EEAE5.2040304(a)mail1.stofanet.dk> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > On 04/04/2014 02:10 PM, Lars Viklund wrote: > >> As for the Copy-on-Write semantics, isn't the general consensus that CoW >> is a horrible horrible thing and is very hard to get right+fast in the >> modern world with concurrency? > > Yes: > > http://www.gotw.ca/publications/optimizations.htm > Hi, Bjorn, 1) Proposed Copy-on-Write (CoW) optimization will be only option. Developer will chose, which container he or she wants: a) without CoW, b) with CoW with internal locks, c) with CoW without internal locks (very dangerous). Option "a" will be the first choise. Option "c" is used either in single-threaded apps or if he/she knows that all shallow copies are maintained in the single thtread or behind single semaphore which protects all shallow copies. 2) The article states mostly that there are ineffective optimizations of CoW. CoW by itself is not that bad. Citation: Plain 1726ms Plain_FastAlloc 642ms COW_Unsafe 1629ms COW_AtomicInt 1949ms COW_CritSec 10660ms COW_Mutex 33298ms e.g., the AtomicInt is 10-15% slower than plain, while Mutex 33 times. 3) There are situations where it's worth. Firstly, mobile/embedded devices are memory greedy. Secondly, small changes in very large arrays, such as text editors. Thirdly, no need to implement "undo" command in text editors, that reduces development time. But I see that community does not appreciate this feature so I do it in the end of my priority list. Best regards, A.K.

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[git] Near future.. How do we deal with git-native libraries?
by Rene Rivera 05 Apr '14

05 Apr '14

As the owner of the Predef library which exists originally in github and not svn.. I'm wondering about some things for the near future (as in this coming week): 1. Where will the git repo live for a library? Will the repo need to stay in the boostorg organization? Or is it possible/desirable to use the existing repo that's part of my user account? 2. I notice that there's a ".gitattributes" file in the svn imported version of the Predef repo. Will I need to add that file to my actual Predef git repo? And if so, is there a single canonical version of that file I should use? And a followup.. In the future if that file changes, does it need to change for all repos consistently? Rene. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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