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[FunctionTypes] Getting functor/lambda parameters (VS2012)
by Mateusz Loskot 23 Jun '13

23 Jun '13

Hi, I'm using C++ compiler from the latest VS2012. I'm trying this simple technique to determined type of functor or lambda call parameter, it works well: #include <boost/function_types/parameter_types.hpp> int main() { auto foo = [](int) -> void {}; typedef decltype(foo) foo_type; typedef boost::function_types::parameter_types < decltype(&foo_type::operator()) >::type parameter_types; } Next, I move the typedef into class template, in constructor body, it works well too: template <typename T> struct A { A(T t) { typedef typename boost::function_types::parameter_types < decltype(&T::operator()) >::type parameter_types; } }; Finally, I move further with the technique, so I can access parameter types within class template scope: template <typename T> struct B { typedef typename boost::function_types::parameter_types < decltype(&T::operator()) >::type parameter_types; }; This example does compile with clang 3.4 (svn trunk) and GCC 4.8.1, but it does not compile with Visual C++ 11.0. Does anyone understand what C++11 feaure VS2012 is lacking so it prevents compilation of the sample with B template above? Here is complete .cpp file https://gist.github.com/mloskot/5846468 Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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install with b2 - conflicting documentation
by Kirk Joppy 23 Jun '13

23 Jun '13

Hello, I am trying to build the regex library which I will then use through MinGW. I already installed MinGW and added ..\MinGW\bin to my system PATH. I now want to build regex and put it somewhere. I am aware of two different pieces of documentation detailing how to do this: http://www.boost.org/doc/libs/1_53_0/more/getting_started/windows.html#prep… http://www.boost.org/doc/libs/1_53_0/doc/html/bbv2/installation.html The main difference seems to be whether you should be in BOOST_ROOT or BOOST_ROOT\tools\build\v2. Which is it? In either case I gather than I should do this $ bootstrap.bat gcc and in fact I've done that in both BOOST_ROOT and BOOST_ROOT\tools\build\v2 with apparent success. I just don't know what I'm supposed to do next. I tried running $ b2 --prefix=H:\boost-test --with-regex install from within BOOST_ROOT\tools\build\v2, and that put some stuff into H:\boost-text, but I couldn't find any actual library files. Before I screw around any more I thought I'd ask knowledgeable folks for the right way to do this. Thank you very much, kjoppy

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An example: how I learned to iterate through property trees (ptree)
by Cook, Rich 22 Jun '13

22 Jun '13

I just wanted to post a program I wrote that creates a boost::ptree, saves it to JSON, reads it back, then iterates through the tree and prints its nodes. #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <string> #include <iostream> using namespace std; using boost::property_tree::ptree; string indent(int level) { string s; for (int i=0; i<level; i++) s += " "; return s; } void printTree (ptree &pt, int level) { if (pt.empty()) { cerr << "\""<< pt.data()<< "\""; } else { if (level) cerr << endl; cerr << indent(level) << "{" << endl; for (ptree::iterator pos = pt.begin(); pos != pt.end();) { cerr << indent(level+1) << "\"" << pos->first << "\": "; printTree(pos->second, level + 1); ++pos; if (pos != pt.end()) { cerr << ","; } cerr << endl; } cerr << indent(level) << " }"; } return; } int main(int, char*[]) { // first, make a json file: string tagfile = "testing2.pt"; ptree pt1; pt1.put("object1.type","ASCII"); pt1.put("object2.type","INT64"); pt1.put("object3.type","DOUBLE"); pt1.put("object1.value","one"); pt1.put("object2.value","2"); pt1.put("object3.value","3.0"); pt1.put("object4.type", "ASCII"); pt1.put("object4.value", "shallow"); pt1.put("object4.subobject1.type", "ASCII"); pt1.put("object4.subobject1.value", "deep child"); pt1.put("object4.subobject1.subsubobject.type", "ASCII"); pt1.put("object4.subobject1.subsubobject.value", "deep child"); pt1.put("object5.type", "ASCII"); pt1.put("object5.value", "shallow"); write_json(tagfile, pt1); ptree pt; bool success = true; //try { read_json(tagfile, pt); printTree(pt, 0); cerr << endl; return success; } PROGRAM OUTPUT: rcook@rzbeast (blockbuster): ./ptree { "object1": { "type": "ASCII", "value": "one" }, "object2": { "type": "INT64", "value": "2" }, "object3": { "type": "DOUBLE", "value": "3.0" }, "object4": { "type": "ASCII", "value": "shallow", "subobject1": { "type": "ASCII", "value": "deep child", "subsubobject": { "type": "ASCII", "value": "deep child" } } }, "object5": { "type": "ASCII", "value": "shallow" } } -- ✐Richard Cook ✇ Lawrence Livermore National Laboratory Bldg-453 Rm-4024, Mail Stop L-557 7000 East Avenue, Livermore, CA, 94550, USA ☎ (office) (925) 423-9605 ☎ (fax) (925) 423-6961 --- Information Management & Graphics Grp., Services & Development Div., Integrated Computing & Communications Dept. (opinions expressed herein are mine and not those of LLNL)

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[smart_ptr] enable_shared_from_this and shared_ptr to a base class
by Adam Romanek 21 Jun '13

21 Jun '13

Hi, I have a question related to using shared_from_this() and a shared_ptr to a base class. Here's a modified version of the enable_shared_from_this usage example from its documentation web page: #include <boost/enable_shared_from_this.hpp> #include <boost/shared_ptr.hpp> #include <cassert> class X { public: virtual void foo() = 0; }; class Y: public X, public boost::enable_shared_from_this<Y> { virtual void foo() { shared_from_this(); } }; int main() { X* x_ptr = new Y; boost::shared_ptr<X> sp(x_ptr); sp->foo(); } First, class Y is now derived from class X. Secondly, shared_ptr's template argument is now X and the parameter to the shared_ptr's constructor is now a pointer to X. Now, calling shared_from_this() in X and/or Y throws boost::bad_weak_ptr. Is this correct behavior? Is it documented somewhere? I know that the example is a bit unrealistic since most of the time shared_ptr is constructed directly from the pointer returned by 'new Y' or created by make_shared() but still, this is something that bothers me. WBR, Adam Romanek

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Re: [Boost-users] [Test]: Problem with simple Boost.Test
by Damien Kick 21 Jun '13

21 Jun '13

On Jun 20, 2013, at 8:38 PM, <boost-users-request(a)lists.boost.org<mailto:boost-users-request@lists.boost.org>> wrote: Date: Thu, 20 Jun 2013 17:01:54 +0000 (UTC) From: Gennadiy Rozental <rogeeff(a)gmail.com<mailto:rogeeff@gmail.com>> To: boost-users(a)lists.boost.org<mailto:boost-users@lists.boost.org> Subject: Re: [Boost-users] [Test]: Problem with simple Boost.Test Message-ID: <loom.20130620T185812-619(a)post.gmane.org<mailto:loom.20130620T185812-619@post.gmane.org>> Content-Type: text/plain; charset=utf-8 thusly:$ ${CXX} -c --std=c++0x -g -I${TARGET}/include cma.cpp -o cma.o $ ${CXX} --std=c++0x -g cma.o ${TARGET}/lib/libboost_test_exec_monitor.a \ ${TARGET}/lib/libboost_unit_test_framework.dylib -o cma I know docs are not ideal but this part is very clear I thought. test_exec_monitor is an old alternative t ounit test framework, which is long deprecated and they definitely do not require each other In this case, I wouldn't fault the docs per se but rather only my impatience in having tried "jumping directly to the subject of [my] interest" but not yet having realized exactly what my subject of interest really is/was nor how far I needed to jump in order to get to it ;-) I had been trying this: $ cat cma.cpp #define BOOST_TEST_MODULE cma #include <boost/test/unit_test.hpp> #include <iostream> #include <ostream> BOOST_AUTO_TEST_CASE(sanity) { std::clog << "Test the world!\n"; } $ ${CXX} -c --std=c++0x -g -I${TARGET}/include cma.cpp -o cma.o $ ${CXX} --std=c++0x -g cma.o ${TARGET}/lib/libboost_unit_test_framework.dylib -o cma Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status $ But when I started reading through more of the documentation and got as far as <http://preview.tinyurl.com/lw7e688>, I realized that I needed to be doing something more like this: $ ${CXX} -c --std=c++0x -g -DBOOST_TEST_DYN_LINK -I${TARGET}/include cma.cpp -o cma.o $ ${CXX} --std=c++0x -g cma.o ${TARGET}/lib/libboost_unit_test_framework.dylib -o cma $ env DYLD_LIBRARY_PATH=${TARGET}/lib ./cma Running 1 test case... Test the world! *** No errors detected $ Thank you, Gennadiy, for having taken the time to respond to my question as well as having taken the time you spent on Boost.Test. ________________________________ This e-mail and any attachments are confidential. If it is not intended for you, please notify the sender, and please erase and ignore the contents.

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Re: [Boost-users] [Test]: Problem with simple Boost.Test
by Damien Kick 21 Jun '13

21 Jun '13

Date: Mon, 17 Jun 2013 23:03:16 +0000 (UTC) From: legalize+jeeves(a)mail.xmission.com<mailto:legalize+jeeves@mail.xmission.com> (Richard) To: boost-users(a)lists.boost.org<mailto:boost-users@lists.boost.org> Subject: Re: [Boost-users] [Test]: Problem with simple Boost.Test Message-ID: <kpo4jk$2ih$2(a)ger.gmane.org<mailto:kpo4jk$2ih$2@ger.gmane.org>> [Please do not mail me a copy of your followup] boost-users(a)lists.boost.org<mailto:boost-users@lists.boost.org> spake the secret code <7364AB234369D348AE1CEBC1A86132DBAD32EA(a)SVLITMX02.shoretel.com<http://SVLITMX02.shoretel.com>> thusly: $ ${CXX} -c --std=c++0x -g -I${TARGET}/include cma.cpp -o cma.o $ ${CXX} --std=c++0x -g cma.o ${TARGET}/lib/libboost_test_exec_monitor.a \ ${TARGET}/lib/libboost_unit_test_framework.dylib -o cma Why are you linking against boost_test_exec_monitor? I've never needed to do that. boost_unit_test_framework should be enough. Interesting. Because I'm finding the following: $ ${CXX} -c --std=c++0x -g -I${TARGET}/include cma.cpp -o cma.o $ ${CXX} --std=c++0x -g cma.o ${TARGET}/lib/libboost_unit_test_framework.dylib -o cma Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status $ But that is also what I'm finding with the system GCC and the Fink install of Boost 1.46, and so that behavior isn't unique my attempt to build/use a Boost with GCC 4.8.0 using --std=c++0x. $ g++ -c -g -I/sw/include cma.cpp -o cma.o $ g++ -g -L/sw/lib cma.o -lboost_unit_test_framework-mt Undefined symbols for architecture x86_64: "_main", referenced from: start in crt1.10.6.o ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status $ g++ --version i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00) Copyright (C) 2007 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ fink list --tab boost1.46 Information about 7237 packages read in 1 seconds. i boost1.46.1.cmake 1.46.1-2 Boost C++ Libraries i boost1.46.1.cmake-shlibs 1.46.1-2 Boost C++ Libraries $ ________________________________ This e-mail and any attachments are confidential. If it is not intended for you, please notify the sender, and please erase and ignore the contents.

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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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