May 2009 - Boost-users - lists.preview.boost.org

iterators must go
by Neal Becker 21 May '09

21 May '09

Interesting presentation: http://www.boostcon.com/site- media/var/sphene/sphwiki/attachment/2009/05/08/iterators-must-go.pdf

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Persisting __int64 (or long long) with boost::serialization?
by Sandy Walsh 21 May '09

21 May '09

Hi, Sorry for the n00b question, but I'm trying to serialize some unsigned __int64 member variables using boost::serialization. I added the following to my header: namespace boost { namespace serialization { template<class Archive> void load(Archive & ar, unsigned __int64& big, const unsigned int version) { size_t size = sizeof(big); ar.load_binary(&big, size); } template<class Archive> void save(Archive & ar, unsigned __int64 big, const unsigned int version) { ar & sizeof(big); ar.save_binary(&big, sizeof(big)); } } }; But the compiler still complains that it doesn't know how to handle that right-hand operand. Is there something obvious here I'm missing? Thanks -S

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Declare statistical distribution array: boost/math/distributions
by Alex Tsoi 21 May '09

21 May '09

Hi all, I am trying to write a MCMC algorithm by using boost's math distribution library, what I want to do is to first declare an array of length 10 of gamma distribution, and then run a for loop to declare each gamma distribution's parameters. However, boost does not allow me to declare the gamma distribution array without having defining the parameter in advance: gamma_distribution<double> mydist10[10]; error: no appropriate default constructor available. because the library requires to know the parameter of the gamma distribution in advance. Do you guys have any idea to overcome this ? Thanks a lot for any comment or suggestion. Alex- -- Lam C. Tsoi (Alex) Medical University of South Carolina

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Boost'Con aftermath
by Joel Falcou 21 May '09

21 May '09

I wanted to know what will the paper submitted to boost'con become ? Is there any publication planned or not ? Just asking to know if I can quote the thing I did for Boost'Con 09 in other papers ;) Regards -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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boost::iostreams filter question
by plarroy 21 May '09

21 May '09

Hello, I have implemented a test SymmetricFilter and works ok. Although to my suprise I had to declare two different methods of filter differing only in the signature by the const char*& src_end. If I supress either of those i get a compile time error. Perhaps it is because it's being used as a bidirectional filter? as the two signatures might be the ones in boost/iostreams/filter/symmetric.hpp read and write? Pedro. Regards. My code: class smashing_filter_impl { public: typedef char char_type; smashing_filter_impl() { } bool filter(const char*& src_begin, char*& src_end, char*& dst_begin, char*& dst_end, bool flush) { bool eof = false; ptrdiff_t src_sz = src_end - src_begin; if( src_sz <= 0 ) return false; while(src_begin < src_end && dst_begin < dst_end) *dst_begin++ = tolower(*src_begin++); return true; } bool filter(const char*& src_begin, const char*& src_end, char*& dst_begin, char*& dst_end, bool flush) { bool eof = false; ptrdiff_t src_sz = src_end - src_begin; if( src_sz <= 0 ) return false; while(src_begin < src_end && dst_begin < dst_end) *dst_begin++ = tolower(*src_begin++); return true; } void close() {} private: }; struct smashing_filter : symmetric_filter<smashing_filter_impl> { public: typedef symmetric_filter<smashing_filter_impl> base_type; smashing_filter() : base_type(default_device_buffer_size) { } };

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Boost Library on ThreadX RTOS
by Suraj Gupta, Gurgaon 21 May '09

21 May '09

Hi All, I want to use BOOST library (Test) on ThreadX Real Time Operating System. Can it be used on ThreadX? If possible, are there any guidelines those needs to be followed? Thanks, Suraj DISCLAIMER: ----------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or HCL or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of the author of this e-mail is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any mail and attachments please check them for viruses and defect. -----------------------------------------------------------------------------------------------------------------------

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[variant] apply templated visitor
by Dmitry Vinogradov 20 May '09

20 May '09

Imagine the following: struct foo { bar& operator[](int); bar& operator[](std::string); } Foo; boost::variant<int, std::string> Idx; Is some simple way exist to apply foo::operator[](T) for Foo and Idx? Something like boost::apply_visitor(boost::bind(&foo::operator[], boost::ref(Foo), _1), Idx); // does not compile

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find the largest/most precise of two types
by Alex Flint 20 May '09

20 May '09

Hi there, I have a bunch of functions that accept two numeric arguments. In the case that the types of these arguments are different I want to figure out what the return type should be. The rule I would like to use is that the largest of the two types should be used for internal computations and the return type. f(someFloat, someDouble) -> double f(someFloat, someFloat) -> float f(someInt, someFloat) -> float Is there a way I can do this, perhaps with boost's type_traits? Cheers, Alex

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Error (runtime) assigning multi_array to multi_array with smaller dimensions
by Matheus Araújo Aguiar 20 May '09

20 May '09

Hello everyone, I'm getting an error when trying to get one sub array from a multi_array with 2 dimensions. This is the code: //at class constructor boost::multi_array<char, 2> array2d = new boost::multi_array<char, 2>(boost::extents[x][y]); ... //at class method boost::multi_array<char, 1> array1d = array2d[0]; And the error i got: Reference boost::detail::multi_array::value_accessor_n<T, NumDims>::access(boost::type<Reference>, boost::multi_array_types::index, TPtr, const boost::multi_array_types::size_type*, const boost::multi_array_types::index*, const boost::multi_array_types::index*) const [with Reference = boost::detail::multi_array::sub_array<char, 1u>, TPtr = char*, T = char, unsigned int NumDims = 2u]: Assertion `size_type(idx - index_bases[0]) < extents[0]' failed. Could anyone help, please? Thanx, -- Matheus Araújo Aguiar Computer Scientist matheus.pit(a)gmail.com

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To find adjacent vertices using Boost Graph....
by Amanullah Yasin 20 May '09

20 May '09

Hi, Dear All, In the graph of nodes (e.g. 1 , 2, 3, 4, 5, 6 , 7........). I want to iterate to the adjacent nodes of node x. For this i am using adjacent_vertices(v, g), which returns std::pair<adjacency_iterator, adjacency_iterator> for (i = 1; i <= n; i++){ tie(eo, eo_end) = adjacent_vertices( vertex( i-1, graph), graph); } Please guide me how i can use the adjacency_iterator to access the neighbourhood of node x ? e.g. graph is a 1 ---- 2 3 4 5 2 ---- 4 5 6 3 ---- 5 6 7 so, neighbourhood of 1 are 2 3 4 5 2 are 4 5 6 3 are 5 6 7 I will be thankful to you. Regards Amanullah YASIN Master2 (ECD) Ecole Polytechnique Université de Nantes, France. Mob# 06 47 62 89 96 Fix # 02 72 00 26 45 amanyasin(a)gmail.com

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