March 2013 - Boost-users - lists.preview.boost.org

adjacency matrix subgraph enumeration
by headupinclouds 09 Mar '13

09 Mar '13

What is the best way in boost to enumerate all connected subgraphs of an adjacency matrix? I know in advance that all nodes of the graph are connected and that it is cyclic. For the following graph: (0 <-> 1) (1 <-> 2) (2 <-> 3) (3 <-> 0) I want to enumerate the node list of all unique connected subgraphs: (0, 1) (0, 1, 2) (0, 1, 2, 3) (1, 2) (1, 2, 3) (2, 3) (0, 3) (0, 3, 2) -- View this message in context: http://boost.2283326.n4.nabble.com/adjacency-matrix-subgraph-enumeration-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

is_foo_type naming rule
by Niitsuma Hirotaka 09 Mar '13

09 Mar '13

There are two type is_foo_type functor For example is_double can be --------- template<typename T> struct is_double_template : boost::is_same<T,double> {}; --------- or --------- struct is_double_runtime { template<typename T> bool operator()(T x){return false;} bool operator()(double x){return true;} }; --------- Are there any standard naming rule distinguish these functor? is_foo_runtime is_foo_compiletime ? The compile-time functor can convert to runtime factor using : --------- template<typename IsTemplateMplLambda> struct is_templated_type_to_runtime { typedef struct is_templated_type_runtime { template<typename T> bool operator()(T) { return boost::mpl::apply<IsTemplateMplLambda,T>::type::value; } } type; }; --------- usage --------- typedef boost::mpl::lambda<is_double_template<boost::mpl::_1 > >::type is_double_mpl_lambda; double x=1.1; int i=2; is_templated_type_to_runtime<is_double_mpl_lambda>::type is_double_runtime_object; std::cout << is_double_runtime_object(x) << std::endl; std::cout << is_double_runtime_object(i) << std::endl; ---------

3 3

newbie needs help with a linker problem
by Phil Huffman 09 Mar '13

09 Mar '13

Hello, I just installed Boost and GMP on my Mac, using all defaults. I want to use GMP via Boost, but there is a problem with the linker. I'm sure that clang is getting a bit lost looking for GMP's object modules. Any help will be gratefully accepted. Thanks. When I compile the below program: #include <boost/multiprecision/gmp.hpp> using namespace boost::multiprecision; int main() { mpz_int v = 1; for (unsigned i = 1; i <= 1000; ++i) { v *= i; } std::cout << "1000! = " << v << std::endl; // prints 1000! return 0; } using this command: c++ -I /usr/local/boost_1_53_0 mpz1.cpp -o mpz1 -v I get this: Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn) Target: x86_64-apple-darwin12.2.0 Thread model: posix "/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.8.0 -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name mpz1.cpp -pic-level 1 -mdisable-fp-elim -relaxed-aliasing -masm-verbose -munwind-tables -target-cpu core2 -target-linker-version 134.9 -v -resource-dir /usr/bin/../lib/clang/4.1 -I /usr/local/boost_1_53_0 -fmodule-cache-path /var/folders/hj/zc5pjqjd6gxgq2sw77xghkyh0000gn/T/clang-module-cache -fdeprecated-macro -fdebug-compilation-dir /Users/56phil/Dev/boostTest -ferror-limit 19 -fmessage-length 272 -stack-protector 1 -mstackrealign -fblocks -fobjc-runtime-has-arc -fobjc-runtime-has-weak -fobjc-dispatch-method=mixed -fobjc-default-synthesize-properties -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o /var/folders/hj/zc5pjqjd6gxgq2sw77xghkyh0000gn/T/mpz1-KE6NKq.o -x c++ mpz1.cpp clang -cc1 version 4.1 based upon LLVM 3.1svn default target x86_64-apple-darwin12.2.0 ignoring nonexistent directory "/usr/include/c++/4.2.1/i686-apple-darwin10/x86_64" ignoring nonexistent directory "/usr/include/c++/4.0.0" ignoring nonexistent directory "/usr/include/c++/4.0.0/i686-apple-darwin8/" ignoring nonexistent directory "/usr/include/c++/4.0.0/backward" #include "..." search starts here: #include <...> search starts here: /usr/local/boost_1_53_0 /usr/include/c++/4.2.1 /usr/include/c++/4.2.1/backward /usr/local/include /usr/bin/../lib/clang/4.1/include /usr/include /System/Library/Frameworks (framework directory) /Library/Frameworks (framework directory) End of search list. "/usr/bin/ld" -demangle -dynamic -arch x86_64 -macosx_version_min 10.8.0 -o mpz1 /var/folders/hj/zc5pjqjd6gxgq2sw77xghkyh0000gn/T/mpz1-KE6NKq.o -lstdc++ -lSystem /usr/bin/../lib/clang/4.1/lib/darwin/libclang_rt.osx.a Undefined symbols for architecture x86_64: "___gmp_get_memory_functions", referenced from: boost::multiprecision::backends::gmp_int::str(long, std::_Ios_Fmtflags) const in mpz1-KE6NKq.o "___gmpz_clear", referenced from: boost::multiprecision::backends::gmp_int::~gmp_int() in mpz1-KE6NKq.o "___gmpz_get_str", referenced from: boost::multiprecision::backends::gmp_int::str(long, std::_Ios_Fmtflags) const in mpz1-KE6NKq.o "___gmpz_init", referenced from: boost::multiprecision::backends::gmp_int::operator=(long) in mpz1-KE6NKq.o boost::multiprecision::backends::gmp_int::gmp_int() in mpz1-KE6NKq.o "___gmpz_mul_ui", referenced from: boost::multiprecision::backends::eval_multiply(boost::multiprecision::backends::gmp_int&, unsigned long) in mpz1-KE6NKq.o "___gmpz_set_si", referenced from: boost::multiprecision::backends::gmp_int::operator=(long) in mpz1-KE6NKq.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

2 1

building with iostreams and a non-standard zlib location
by James Amundson 09 Mar '13

09 Mar '13

Hi, I'm trying to do a bjam build of boost packages including iostreams. I have zlib installed under /unusual/location ./bjam include=/unusual/location/include install fails because it cannot find -lz. Obviously, I need to specify that libz is in /unusual/location/lib, but I don't see how to do that. I realize this seems obvious. Which part of the documentation am I missing? Thanks, Jim Amundson

4 3

VS2012 C4503 warning (decorated name length exceeded, name was truncated) with boost 1.52
by legalize+jeeves＠mail.xmission.com 08 Mar '13

08 Mar '13

[Please do not mail me a copy of your followup] I'm using boost 1.52. If you see this thread on stack overflow: <http://stackoverflow.com/questions/9669071/warning-c4503-when-using-pragma-…> You'll see a comment down at the bottom where someone has increased the warning level for their project and they are getting tons of these C4503 warnings when using boost includes. I have verified on my project that if I don't change the warning level and don't specifically disable this warning project-wide, then including using boost in my project does not generate the warning. However, if I increase the warning level beyond the default, to 3 in my case whereas the poster on stack overflow had used 4, then I get the warning. I, like the commenter on stack overflow, would like to know if there's a boost-friendly way to tell boost to disable the warning for boost headers where the boost authors have decided it's innocuous, while still retaining the high warning setting for my own code. Any suggestions? Thanks in advance. -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://computergraphicsmuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

2 2

Scale-free networks generation
by davidrey123 08 Mar '13

08 Mar '13

Hello, I would to use Boost librairies to generate scale-free networks and I am not sure what is the best approach. I am currently using the PLOD generator, but the graphs generated are generally multigraphs, that is, graphs with multiple edges between two nodes. Although I would like to generate graphs with bidirectionnal edges between nodes, I also would like to bound the maximum number of possible edges between a pair of nodes to 2. In other words, if edges (i,j) and (j,i) are generated between nodes i and j, I do not want any additional edge between those nodes to be generated. Hence, I would like to know; 1-Is it possible to generate such graphs using the PLOD generator? If it is, do I need to remove "multi-edges" after the graph is generated or is there a smarter way to do so? 2-If using the PLOD generator is not the best option, is there any other random graph generator in Boost that can be adapted to design scale-free networks? In particular, is there a graph generator implementing the Barabasi-Albert model (I have looked up the forum for an answer to that question and it seems that the answer is "no", but things may have changed since)/ 3-I read somewhere that Compressed Sparse Row (CSR) graphs could be used to represent scale-free networks, is there a way to use the corresponding Boost class to do so? Thank you, -David -- View this message in context: http://boost.2283326.n4.nabble.com/Scale-free-networks-generation-tp4643888… Sent from the Boost - Users mailing list archive at Nabble.com.

3 4

[type traits / MPL] check whether a class has a certain member function
by Stefan Strasser 08 Mar '13

08 Mar '13

Hi, I'm looking for a boost functionality to determine whether a given type has a member function of a given name (or name + signature). this seems to be possible using SFINAE, but all I can find is BOOST_MPL_HAS_XXX_TRAIT_DEF which only works for nested types, not functions. I could of course implement it myself using SFINAE but BOOST_MPL_HAS_XXX_TRAIT_DEF has a lot of compiler bug workarounds it seems, so I guess this will cause problems. Is there such a functionality in boost? I want to use it to determine the defaults of a traits class, similar to C++11 pointer_traits::difference_type. But the determining factor for the default is a function in my case, not a type. Thanks

4 6

Using BOOST_*_EQUAL on bit-fields?
by Chris Cleeland 07 Mar '13

07 Mar '13

I'm using the Boost Unit Test Framework and have a struct with bitfields declared in it. When I compile a unit test with code like this StructWithBitfields mystruct; StructWithBitfields otherstruct; BOOST_CHECK_EQUAL(mystruct.bitfield, otherstruct.bitfield); I get a compiler errors error: non-const reference cannot bind to bit-field 'bitfield' referring to both arguments to the macro. Is there a preferred way for comparing bitfield values via unit test macros? -- Chris Cleeland

1 0

Boost.Function compile error
by gast128 07 Mar '13

07 Mar '13

Dear all, i got a compilation error with vstudio 2010 and Boost.Function: 1) pass functor in constructor 2) pass functor as assignment 3) use Boost.Ref 4) temporary function void foo() { std::identity<int> bla; boost::function<int (int)> fc(bla); boost::function<int (int)> fc2 = bla; boost::function<int (int)> fc(boost::ref(bla)); boost::function<int (int)>(bla); //<-- } first 3 are ok, but the last one vstudio sees this as redefintion of bla of type 'boost::function<int (int)>. What (and why) do I wrong or should use an explicit cast in the last case?

3 8

Re: [Boost-users] asio: async ops in multithreading environment
by Marat Abrarov 06 Mar '13

06 Mar '13

> 1) One thread issues scatter-gather boost::asio::async_write() for > boost::array<boost::asio::const_buffer, 2> on socket A. > 2) Another thread closes socket A after that. > 3) Meantime (simultaneously with 2), first buffer write is completed and > one of the threads running io_service::run() starts to execute second part > of async_write from 1). > > The problem is: second write which is issued internally by boost cannot be > protected by the same mutex which is used for protected access to the > socket in my code. At first, RTFM: 1. http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/reference/Handler.h tml ~~~~~~~~~~~~~~ asio_handler_invoke(f, &h); ~~~~~~~~~~~~~~ 2. http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/overview/core/stran ds.html ~~~~~~~~~~~~~~ In the case of composed asynchronous operations, such as async_read() or async_read_until(), if a completion handler goes through a strand, then all intermediate handlers should also go through the same strand. This is needed to ensure thread safe access for any objects that are shared between the caller and the composed operation (in the case of async_read() it's the socket, which the caller can close() to cancel the operation). This is done by having hook functions for all intermediate handlers which forward the calls to the customisable hook associated with the final handler: ~~~~~~~~~~~~~~ Than google some more: 3. https://github.com/boostcon/2011_presentations/raw/master/mon/thinking_async hronously.pdf See template <class Handler> struct mutex_wrapper at page 95. 4. http://asio-samples.blogspot.ru/2011/06/design-journeys-with-asio.html Sorry, it's in Russian. Regards, Marat Abrarov.

1 0