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matrix inversion in boost.
by Mohit Singh 21 Jun '13

21 Jun '13

Hi, I am trying to do a simple matrix inversion operation using boost. But I am getting an error. Basically what I am trying to find is inversted_matrix = inverse(trans(matrix) * matrix) But I am getting an error Check failed in file boost_1_53_0/boost/numeric/ublas/lu.hpp at line 299: detail::expression_type_check (prod (triangular_adaptor<const_matrix_type, upper> (m), e), cm2) terminate called after throwing an instance of 'boost::numeric::ublas::internal_logic' what(): internal logic Aborted (core dumped) My attempt: #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/vector.hpp> #include <boost/numeric/ublas/io.hpp> #include <boost/numeric/ublas/vector_proxy.hpp> #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/triangular.hpp> #include <boost/numeric/ublas/lu.hpp> namespace ublas = boost::numeric::ublas; template<class T> bool InvertMatrix (const ublas::matrix<T>& input, ublas::matrix<T>& inverse) { using namespace boost::numeric::ublas; typedef permutation_matrix<std::size_t> pmatrix; // create a working copy of the input matrix<T> A(input); // create a permutation matrix for the LU-factorization pmatrix pm(A.size1()); // perform LU-factorization int res = lu_factorize(A,pm); if( res != 0 ) return false; // create identity matrix of "inverse" inverse.assign(ublas::identity_matrix<T>(A.size1())); // backsubstitute to get the inverse lu_substitute(A, pm, inverse); return true; } int main(){ using namespace boost::numeric::ublas; matrix<double> m(4,5); vector<double> v(4); vector<double> thetas; m(0,0) = 1; m(0,1) = 2104; m(0,2) = 5; m(0,3) = 1;m(0,4) = 45; m(1,0) = 1; m(1,1) = 1416; m(1,2) = 3; m(1,3) = 2;m(1,4) = 40; m(2,0) = 1; m(2,1) = 1534; m(2,2) = 3; m(2,3) = 2;m(2,4) = 30; m(3,0) = 1; m(3,1) = 852; m(3,2) = 2; m(3,3) = 1;m(3,4) = 36; std::cout<<m<<std::endl; matrix<double> product = prod(trans(m), m); std::cout<<product<<std::endl; matrix<double> inversion(5,5); bool inverted; inverted = InvertMatrix(product, inversion); std::cout<<inversion<<std::endl; } -- Mohit "When you want success as badly as you want the air, then you will get it. There is no other secret of success." -Socrates

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[BGL] boykov_kolbogorov_max_flow() classes / groups
by Nil Goyette 20 Jun '13

20 Jun '13

I have been testing the the boykov_kolbogorov_max_flow function in the previous weeks and I have a question that I can't seem to find the answer myself. I asked for it on StackOverflow [1] but nobody answered. Can someone tell me why I get three classes (groups) instead of two? I always get class '0' and '4', and '1' on some cases. I thought a Graph Cut was supposed to output only two classes, so what's the meaning of '1'? Please read the SO question in [1] for more details. Thanks for your time. Nil Goyette [1] http://stackoverflow.com/questions/16905613/3-classes-0-1-4-on-boost-graph-…

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accumulator extended quantil value
by Philipp Kraus 20 Jun '13

20 Jun '13

Hello, I have got created an extended_p_square_quantile into an accumulator, with 3 quantils (0.25, 0.5, 0.75) as a boost::array. How can I get access to the quantil values of the accumulator? For the variance I use accumulator::variance(myacc), but a call with quantil(myacc, 0.5) does not work. Thanks Phil

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boost_1_53_0: no matching function for call to ‘hash_value
by Shailja Kumari 20 Jun '13

20 Jun '13

> Hi , > > I am using boost_1_53_0 for my applications build. The boost_1_53_0 is > throwing the following error message. > > boost_1_53_0/boost/functional/hash/extensions.hpp:269:34: error: no > matching function for call to ‘hash_value(const > Rubedo::Utils::Hashing::HashedString<16>&)’ > return hash_value(val); > ^ > > boost_1_53_0/boost/functional/hash/hash.hpp:187:57: error: no type named > ‘type’ in ‘struct > boost::hash_detail::basic_numbers<Rubedo::Utils::Hashing::HashedString<16> > >’ > > The following code build fine with boost_1_49_0, but have error with > boost_1_53_0 on linux. Do you have fixes for these ? Please let me know. > > Thanks > >

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boost serialisation, PORTABLE_BINARY_ARCHIVE fix required
by avib369 . 20 Jun '13

20 Jun '13

Currently portable binary archive is broken on AIX platforms. The reason is because the default 'char' type is unsigned on this platform. Whereas for most other platforms it is signed, By going through the portable binary and replacing 'char' with 'signed char' this long standing bug is fixed. I have tested the fix on Linux(opensuse103,opensuse113, HPUX, AIX(power6,power7) This is a fairly safe and quick fix, can I please ask the authors of this library to add this fix, for the next version of boost. Here are the changes I made: (flagged under ' // changed ' comment //-------------------------------------------------------- portable_binary_iarchive.hpp void load(signed char & t){ // changed this->primitive_base_t::load(t); } //------------------------------------------------------------- portable_binary_iarchive.cpp void portable_binary_iarchive::load_impl(boost::intmax_t & l, char maxsize){ signed char size; // changed l = 0; this->primitive_base_t::load(size); if(0 == size){ return; } bool negative = (size < 0); ...... // ----------------------------------------------------------------- portable_binary_oarchive.hpp void save(const signed char & t){ // changed this->primitive_base_t::save(t); } // ----------------------------------------------------------- portable_binary_oarchive.cpp void portable_binary_oarchive::save_impl( const boost::intmax_t l, const char maxsize ){ signed char size = 0; // changed if(l == 0){ this->primitive_base_t::save(size); return; } .......... // ------------------------------ Ta, Avi

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[property_tree] Population and Json formatting
by Michael Powell 20 Jun '13

20 Jun '13

Hello, Question about property tree. I've got an "event" concept which I want to serialize to Json through property tree. If I go something like this: ptree tree; tree.set<int>("event.id", 1); Then the resulting Json would look something like this? { "event": { "id": 1 } } or possibly? { "event": { "id" : "1" } } or possibly, with pretty turned off (nicer for message framing). {"event":{"id":"1"}} Thank you... Regards, Michael Powell

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Boost and Norton 360
by Scott Alexander 20 Jun '13

20 Jun '13

Hi, I have just installed boost 1.53 32bit using the Sourceforge Visual Studio installer and my security software (Norton 360) has quarantined three files as being high risk: *boost_math_tr1f-vc110-mt-1_53.dll *boost_thread-vc110-mt-gd-1_53.dll *boost_filesystem-vc110-mt-gd-1_53.dll Does anyone know if this is common? Can I safely restore these files? Thanks, Scott

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errors in boost build - 1.5.3 on Linux Mint 15 (Olivia) 64-bit
by asif saeed 20 Jun '13

20 Jun '13

Hi, I am trying to build boost 1.53 using GCC and have got the following errors: ...failed updating 348 targets... ...skipped 72 targets... ...updated 4568 targets... The "failed updating 348 targets..." shows that something has definitely gone wrong. Can any kind soul tell me what has happened? I used the following command after bootstrap: ./b2 --prefix=./ --build-type=complete --stagedir=./stage --layout=versioned --toolset=gcc Help me please. -Best regards, -Asif

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[program_options] Custom Validation for a String Value
by Ryan 19 Jun '13

19 Jun '13

Hello, Is there a way of validating a string type program option before it's stored in the map? add_options() ("arg" , value<std::string>()->default_value("Hi"), "Greeting"); boost::regex pattern("^(Hello | Good Morning | Hi)$"); I've used custom validation for types that program options doesn't recognize. I'd like to check the string before it's stored in the map like the custom validation does for unknown types. I'd rather the error be caught early. Is there a way to use the regex against the program option? Ryan

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Mutex synchronised wrapper class for boost::interprocess shared memory vector of strings
by Riskybiz 19 Jun '13

19 Jun '13

I'm trying to write a wrapper class in C++ to give mutex synchronised interprocess access to a shared memory vector of strings. This is my first foray into boost::interprocess and allocators are proving something of a mystery. Is anyone able to see why on compilation I get the error: error C2512: 'boost::interprocess::allocator::allocator' : no appropriate default constructor available C:\Program Files (x86)\Boost\boost_1_53_0\boost\container\string.hpp #ifndef SHARED_MEMORY_WRAPPER_H//if not defined already #define SHARED_MEMORY_WRAPPER_H//then define it #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/containers/string.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/sync/named_mutex.hpp> using namespace boost::interprocess; class SharedMemoryWrapper { public: SharedMemoryWrapper(const std::string &name, bool server) : m_name(name), m_server(server) { if (server) { named_mutex::remove("named_mutex"); shared_memory_object::remove(m_name.c_str()); //Create shared memory managed_shared_memory m_segment(create_only, m_name.c_str(), 10000); //Create allocators CharAllocator charallocator(m_segment.get_segment_manager()); StringAllocator stringallocator(m_segment.get_segment_manager()); //This string is in only in this process (the pointer pointing to the //buffer that will hold the text is not in shared memory). //But the buffer that will hold "this is my text" is allocated from //shared memory MyShmString mystring(charallocator); mystring = "this is my text"; //This vector is fully constructed in shared memory. All pointers //buffers are constructed in the same shared memory segment //This vector can be safely accessed from other processes. MyShmStringVector *sharedSegmentVector = m_segment.construct<MyShmStringVector>("sharedSegmentVector")(stringallocato r); sharedSegmentVector->push_back(mystring); } else { //Open the shared segment managed_shared_memory m_segment(open_only, name.c_str()); //Find the vector using the c-string name and open it MyShmStringVector *sharedSegmentVector = m_segment.find<MyShmStringVector>("sharedSegmentVector").first; } m_mutex = new named_mutex(open_or_create, "named_mutex"); } ~SharedMemoryWrapper() { if (m_server) { named_mutex::remove("named_mutex"); //Destroy the vector from the managed_shared_memory m_segment->destroy_ptr(sharedSegmentVector);//This will free all strings that the vector contains m_segment->destroy<MyShmStringVector>("sharedSegmentVector");//Destroy the vector //Is it necessary to destroy the allocators here? //Remove the managed_shared_memory; this may fail if the memory does not exist or is mapped or opened by another process shared_memory_object::remove(m_name.c_str()); } delete m_mutex; delete m_segment; } //Writer void push(const std::string & in) { scoped_lock<named_mutex> lock(*m_mutex); MyShmString inStr = in.c_str(); sharedSegmentVector->push_back(inStr); } //Reader function yet to be coded. Needs to return a vector containing a subset range of elements from the shared-memory-vector. private: //Typedefs typedef boost::interprocess::allocator<char, managed_shared_memory::segment_manager> CharAllocator; typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> MyShmString; typedef boost::interprocess::allocator<MyShmString, managed_shared_memory::segment_manager> StringAllocator; typedef boost::interprocess::vector<MyShmString, StringAllocator> MyShmStringVector; bool m_server; std::string m_name; managed_shared_memory *m_segment; MyShmStringVector *sharedSegmentVector; named_mutex *m_mutex; };//class #endif//header guard With thanks, Riskybiz

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