June 2012 - Boost-users - lists.preview.boost.org

(no subject)
by Avishay Ben Shabtai 05 Jun '12

05 Jun '12

> > > Hi > > > > I am having compilation error when calling copy_graph. > > The compilation error is regarding vertex_all for default copy of > vertices. > > Where can I find info regarding this property and how to resolve the > issue? > > What graph type are you using? If it is custom, you might have an easier > time passing in your own vertex and edge copying functions, which avoids > the need to have vertex_all or edge_all properties. See > <URL:http://www.boost.org/doc/libs/1_49_0/libs/graph/doc/copy_graph.html> > for information on those parameters. > > -- Jeremiah Willcock I don't understand what is custom graph but my graph definition is: typedef boost::adjacency_list<boost::listS //container class of the edges. ,boost::vecS ,boost::bidirectionalS ,MCVertexProp ,boost::property<boost::edge_weight_t,MCEdgeWeight>s ,MCGraphProp> MCBaseGraph; do i need to declare vertex_all as property and if so what is its type?

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[Boost.Random] Discrete distribution behavior
by sguazt 05 Jun '12

05 Jun '12

Dear Booster, I have a problem in understanding how the boost::random::discrete_distribution works. As far as I know, given the following events: x1, x2 and x2 and weights: 1, 4, and 5, * the associated PDF of the discrete distribution would be: \Pr{X=x1}=1/10 \Pr{X=x2}=4/10 \Pr{X=x3}=5/10 * and the CDF would be: \Pr{X<=x1}=1/10 \Pr{X<=x2}=5/10 \Pr{X<=x3}=1 So, if my random generator generates the value 0.814724, the discrete random variate would return the event x3 (if I'm not wrong). Instead, it seems that boost::random::discrete_distribution does not work in this way. To test it I have implemented a small program (see attachment). Moreover, I have also implemented a naive version of discrete distribution (called my::discrete_distribution), which simply draws a uniform [0,1] random number and select the first event whose CDF is greater than or equal to the drawn value. I have also added some debug prints in other boost classes (just to get the value of the generated random numbers). I run it in Linux with Boost devel version + GCC 4.6.3 (with flags: -Wall -ansi -pedantic) Here's the output: Testing Boost... [boost::random::mersenne_twister] 3499211612 [boost::random::mersenne_twister] 581869302 [boost::random::discrete_distribution] test=0.814724 - result=0 Random Event: 1 [boost::random::mersenne_twister] 3890346734 [boost::random::mersenne_twister] 3586334585 [boost::random::discrete_distribution] test=0.905792 - result=2 Random Event: 2 [boost::random::mersenne_twister] 545404204 [boost::random::mersenne_twister] 4161255391 [boost::random::discrete_distribution] test=0.126987 - result=2 Random Event: 2 Testing My own version... [boost::random::mersenne_twister] 3499211612 [my::discrete_distribution::rand] RNG: 0.814724 Random Event: 2 [boost::random::mersenne_twister] 581869302 [my::discrete_distribution::rand] RNG: 0.135477 Random Event: 1 [boost::random::mersenne_twister] 3890346734 [my::discrete_distribution::rand] RNG: 0.905792 Random Event: 2 As you can see, the sequence of Random Event is different. Looking at the output of my::distribution, it seems it is working OK. Can you help me in understanding what is going on? Thank you very much for the help!! Best, -- Marco

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accumulator operations
by Olaf Peter 04 Jun '12

04 Jun '12

Hi, I like to collects some stats. There are several data slices where I can partially/separated collect them (each of them). Finaly I like to combine these stats to a single one to get summarized informations. How to? May this work: accumulator_set<..> acc1; accumulator_set<..> acc2; ... accumulator_set<..> acc_all; ... acc1(42); ... acc_all += acc1; ... acc_all += acc2; Because did not found informations about. The same problem woulde be probably for a threaded implementation too. Thanks, Olaf

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[uBlas] Linkage problems in assignment.hpp
by Jérémy Coulon 04 Jun '12

04 Jun '12

Hi, I upgraded to Boost v1.49 recently. I am affected by the following bug : https://svn.boost.org/trac/boost/ticket/6010 According to trac, the bug should be fixed in 1.48, right ? Then why is it still there in 1.49 ? Jeremy

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[BGL] copy_graph compilation issue
by Avishay Ben Shabtai 04 Jun '12

04 Jun '12

Hi I am having compilation error when calling copy_graph. The compilation error is regarding vertex_all for default copy of vertices. Where can I find info regarding this property and how to resolve the issue? Sent from my iPad

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[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

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Boost logger parameters.
by Mangesh Sawant 04 Jun '12

04 Jun '12

When I use boost for asynchrous logging, application crashes due to low memory. It seems internal queue maintained by boost during asynch logging is causing this problem. Is there any way to limit size of internal queue, during asynch logging. If I switch to synchronous logging there is no crash. Thanks, Mangesh Sawant.

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Using boost for asynchronous logging.
by Mangesh Sawant 04 Jun '12

04 Jun '12

Hi , Using boost logger for asynchronous logging. Application crashes with bas_alloc exception. When I switch to synchronous logging mode there is no crash. It seems in asynchronous mode log queue size keeps growing leading to low memory. Is there any way(i.e a parameter in setting file) to control max log queue size in asynchronous logging. Thanks, Mangesh Sawant.

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[boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012
by Jeffrey Lee Hellrung, Jr. 04 Jun '12

04 Jun '12

Hi all, The review of the proposed Boost.Multiprecision library authored by John Maddock and Christopher Kormanyos has been scheduled for June 8th - June 17th, 2012 and will be managed by myself. >From the Introduction: -------- "The Multiprecision Library provides *User-defined* integer, rational and floating-point C++ types which try to emulate as closely as practicable the C++ built-in types, but provide for more range and precision. Depending upon the number type, precision may be arbitrarily large (limited only by available memory), fixed at compile time values, for example 50 decimal digits, or a variable controlled at run-time by member functions. The types are expression-template-enabled for better performance than naive user-defined types." -------- And from the original formal review request from John: -------- Features: * Expression template enabled front end. * Support for Integer, Rational and Floating Point types. Supported Integer backends: * GMP. * Libtommath. * cpp_int. cpp_int is an all C++ Boost licensed backend, supports both arbitrary precision types (with Allocator support), and signed and unsigned fixed precision types (with no memory allocation). There are also some integer specific functions - for Miller Rabin testing, bit fiddling, random numbers. Plus interoperability with Boost.Rational (though that loses the expression template frontend). Supported Rational Backends: * GMP * libtommath * cpp_int (as above) Supported Floating point backends: * GMP * MPFR * cpp_dec_float cpp_dec_float is an all C++ Boost licensed type, adapted from Christopher Kormanyos' e_float code (published in TOMS last year). All the floating point types, have full std lib support (cos sin exp, pow etc), as well as full interoperability with Boost.Math. There's nothing in principal to prevent extension to complex numbers and interval arithmetic types (plus any other number types I've forgotten!), but I've run out of energy for now ;-) Code is in the sandbox under /big_number/. Docs can be viewed online here: http://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/h… -------- I hope everyone interested can reserve some time to read through the documentation, try the code out, and post a formal review, either during the formal review window or before. I expect to conduct the review in the "traditional" manner, i.e., entirely within the regular boost developers' mailing list (boost(a)lists.boost.org). I will send a reminder of review process details closer to the review window. Thanks! - Jeff

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Boost threads with arguments
by Jamie Lahowetz 04 Jun '12

04 Jun '12

I am trying to pass two arguments to a boost thread using this call: boost::thread workerthread(&SshClient::SSHconnect,&sshclt,1,provec); the method for SSHconnect is: int SSHconnect(int,vector<string>); When I try to make my program I get the errors: /usr/include/boost/bind/bind.hpp: In member function ‘void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = int (SshClient::*)(int, std::vector<std::basic_string<char> >), A = boost::_bi::list0, A1 = boost::_bi::value<SshClient*>, A2 = boost::_bi::value<int>]’: /usr/include/boost/bind/bind_template.hpp:20:59: instantiated from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()() [with R = void, F = int (SshClient::*)(int, std::vector<std::basic_string<char> >), L = boost::_bi::list2<boost::_bi::value<SshClient*>, boost::_bi::value<int> >, boost::_bi::bind_t<R, F, L>::result_type = void]’ /usr/include/boost/thread/detail/thread.hpp:61:17: instantiated from ‘void boost::detail::thread_data<F>::run() [with F = boost::_bi::bind_t<void, int (SshClient::*)(int, std::vector<std::basic_string<char> >), boost::_bi::list2<boost::_bi::value<SshClient*>, boost::_bi::value<int> > >]’ terminal.cpp:271:1: instantiated from here /usr/include/boost/bind/bind.hpp:313:9: error: no match for call to ‘(boost::_mfi::dm<int(int, std::vector<std::basic_string<char> >), SshClient>) (SshClient*&, int&)’ /usr/include/boost/bind/mem_fn.hpp:314:34: note: candidates are: /usr/include/boost/bind/mem_fn.hpp:340:9: note: R& boost::_mfi::dm<R, T>::operator()(T*) const [with R = int(int, std::vector<std::basic_string<char> >), T = SshClient] /usr/include/boost/bind/mem_fn.hpp:340:9: note: candidate expects 1 argument, 2 provided /usr/include/boost/bind/mem_fn.hpp:345:15: note: const R& boost::_mfi::dm<R, T>::operator()(const T*) const [with R = int(int, std::vector<std::basic_string<char> >), T = SshClient] /usr/include/boost/bind/mem_fn.hpp:345:15: note: candidate expects 1 argument, 2 provided /usr/include/boost/bind/mem_fn.hpp:350:33: note: template<class U> const R& boost::_mfi::dm::operator()(const U&) const [with U = U, R = int(int, std::vector<std::basic_string<char> >), T = SshClient] /usr/include/boost/bind/mem_fn.hpp:357:9: note: R& boost::_mfi::dm<R, T>::operator()(T&) const [with R = int(int, std::vector<std::basic_string<char> >), T = SshClient] /usr/include/boost/bind/mem_fn.hpp:357:9: note: candidate expects 1 argument, 2 provided /usr/include/boost/bind/mem_fn.hpp:362:15: note: const R& boost::_mfi::dm<R, T>::operator()(const T&) const [with R = int(int, std::vector<std::basic_string<char> >), T = SshClient] /usr/include/boost/bind/mem_fn.hpp:362:15: note: candidate expects 1 argument, 2 provided make[2]: *** [terminal.o] Error 1 make[2]: Leaving directory `/home/deadpickle/hprcc_terminal/src' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/home/deadpickle/hprcc_terminal' make: *** [all] Error 2 Quite a long error. Not sure what to make of it and could use some help. thank you. -- Jamie Ryan Lahowetz University of Nebraska - Lincoln Graduate Student - Earth and Atmospheric Sciences 402.304.0766 jlahowetz(a)gmail.com

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