June 2003 - Boost-users - lists.preview.boost.org

RE: [Boost-Users] Struggling with bind
by Jean-Marc Prud'homme 10 Jun '03

10 Jun '03

Hi Paul, _1 is a placeholder argument. When you write bind(&CDocumentAttachments::Execute, _1, _T("print")) you are creating a functor that can be called with a single argument of type CDocumentAttachments. This is what is required by the for_each algorithm. It is equivalent to bind<HINSTANCE>(mem_fn(&CDocumentAttachments::Execute), _1, _T("print")) Look at the mem_fn doc. You still need this kind of functor if you add more arguments to CDocumentAttachments::Execute. This should create the functor you need bind(&CDocumentAttachments::Execute, _1, _T("print"), false) Hope this helps, Jean-Marc -----Original Message----- From: Paul Thompson [mailto:friedegg@ntlworld.com] Sent: Tuesday, June 10, 2003 7:54 AM To: Boost-Users(a)yahoogroups.com Subject: [Boost-Users] Struggling with bind Hi all. I've been using boost::bind to work around deficiencies with std::mem_fun_ref and std::bind2nd under MSVC6. I have a class called CDocumentAttachments which had a member function thus: HINSTANCE Execute(LPCTSTR verb) const; I was using bind with this as follows: for_each(filenames.begin(), filenames.end(), bind(&CDocumentAttachments::Execute, _1, _T("print"))); "filenames" is a const vector of CDocumentAttachments objects. This worked fine. A little later on in development, I changed the function signature for CDocumentAttachments::Execute to: HINSTANCE Execute(LPCTSTR verb, bool visible) const; How will I pass the extra bool to bind? I can't find any examples of passing more than one parameter to a member function. I thought about (among many others) for_each(filenames.begin(), filenames.end(), bind(&CDocumentAttachments::Execute, _2, _T("print"), false)); but the compiler (VC6) complains with two of the following: k:\vc\include\boost\bind.hpp(760) : error C2679: binary '[' : no operator defined which takes a right-hand operand of type 'const class boost::arg<2>' (or there is no acceptable conversion) k:\vc\include\boost\bind\bind_template.hpp(33) : see reference to function template instantiation 'struct HINSTANCE__ *__cdecl boost::_bi::evaluator3<struct HINSTANCE__ *>::eval(const class boost::_bi::list3<class boost::arg<2>,class boost:: _bi::value<char *>,class boost::_bi::value<bool> > &,struct boost::_mfi::cmf2<struct HINSTANCE__ *,class CDocumentAttachments,char const *,bool>,class boost::_bi::list1<class CDocumentAttachments const &> &)' being compiled I know I'm being really thick here, and I'm sure there's something really obvious that I'm missing, but reading through the documentation hasn't helped me. Thank you very much. Paul -- Paul Thompson Programmer McLellan Software Design Ltd. Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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to_simple_string and Windows?
by adutoit 10 Jun '03

10 Jun '03

Hi. I have used the boost::date_time library in Linux with no problems, but the same can not be said of my experience with it in Windows... My current pain in Windows is with the "to_simple_string" method used to convert a boost::date_time value to guess what, a string. This works fine in Linux, but not in stupid Windows. The following line just borks: std::cout << to_simple_string(date(2003,4,30)) << std::endl; Any little unknown configuration tricks etc. I need to be aware of here? Has anyone used the "to_simple_string" method without problems in Windows? I'll appreciate any help in this regard. Greetings, A. [Non-text portions of this message have been removed]

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New file uploaded to Boost-Users
by Boost-Users＠yahoogroups.com 10 Jun '03

10 Jun '03

Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the Boost-Users group. File : /uBLA Performance 2.pdf Uploaded by : sumohurd <matt(a)finray.net> Description : Simplistic uBLA Performance chart, second version You can access this file at the URL http://groups.yahoo.com/group/Boost-Users/files/uBLA%20Performance%202.pdf To learn more about file sharing for your group, please visit http://help.yahoo.com/help/us/groups/files Regards, sumohurd <matt(a)finray.net>

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[crc] Simple example please
by Vladimir Prus 10 Jun '03

10 Jun '03

Hi Alex, > I'd like to calculate a value for a cyclic redundancy check (crc) for a > number of files. > > This isn't going to be transmitted anywhere, I simply want to compare the > values to see whether the files are exactly the same. I know I can simply > check byte for byte, but I've got a few thousand files and it's easier to > calculate the crc for each and see whether any are the same first. Here's the function that I use for the same purpose. Might not be optimal, but works: unsigned file_crc(const string& name) { #if defined(__GNUC__) && __GNUC__ < 3 ifstream ifs(name.c_str(), ios::binary); #else ifstream ifs(name.c_str(), ios_base::binary); #endif if (!ifs) return 0; else { using namespace boost; crc_32_type crc32; int c; while( (c = ifs.rdbuf()->sbumpc()) != -1) crc32.process_byte(char(c)); return crc32.checksum(); } } I believe some example of this kind should be included... Daryle, what do you think? HTH, Volodya

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Lapack for uBlas
by Achim Domma 10 Jun '03

10 Jun '03

Hi, does somebody know a Lapack implementation which can be used with uBlas? I need a solver for an linear equation system and would prefer to not rewrite it by hand. Achim

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vector ranges
by cerenoc 10 Jun '03

10 Jun '03

Hello, I just wanted to clarify if the following behavior is correct. As far as I understood, in matrix and vector range function, the 1st argument defines the starting point and the second defines the length of the range. The following code I ran on gcc 2.96 shows that the behavior is different when starting at 0 and starting somewhere else. Is this a bug, or am I misunderstanding something? Thank you, Julian // define some vector r(3) std::cout << r << "\n\n"; boost::numeric::ublas::vector<double> rr = r(range(0, 0)); std::cout << rr << "\n\n"; rr = r(range(0, 1)); std::cout << rr << "\n\n"; rr = r(range(0, 2)); std::cout << rr << "\n\n"; rr = r(range(0, 3)); std::cout << rr << "\n\n"; //rr = r(range(1, 0)); // THIS RESULTS IN ASSERTION ERROR //std::cout << rr << "\n\n"; rr = r(range(1, 1)); std::cout << rr << "\n\n"; rr = r(range(1, 2)); std::cout << rr << "\n\n"; rr = r(range(1, 3)); std::cout << rr << "\n\n"; OUTPUT: [3](0,1,2) [0]() [1](0) [2](0,1) [3](0,1,2) [0]() [1](1) [2](1,2)

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confused by matrix assignment
by cerenoc 10 Jun '03

10 Jun '03

Hi, I'm sorry I am new to this and also not up on the math notation you guys are using. I am confused by the definitions of slices and strides. I am trying to perform a reasonably simple operation of e.g. assigning a vector v(2) to a (sub)matrix m(3,3). In matlab notation, for instance: m = 0 1 2 3 4 5 6 7 8 v = 15 16 m(2, 1:2) = v Resulting in m = 0 1 2 15 16 5 6 7 8 What is the best way to do this with uBLAS? Thank you very much Julian

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RE: [Boost-Users] Re: Tree Object Needed!
by Jim.Hyslop 09 Jun '03

09 Jun '03

Hossein Haeri wrote: > Does the method you mentioned work for my problem in > which there is no ordering? If yes, please explain it > in more detail (with an example). Trees are generally used with ordered sequences, aren't they? If your data are not ordered, then how do you propose to insert them into the tree? What, well, order would they appear in the tree? If you provide a little more information about the problem domain, we can help you figure out the best container to use. -- Jim

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RE: [Boost-Users] Re: Tree Object Needed!
by Mark Storer 09 Jun '03

09 Jun '03

I don't mean to come off like a hard case, and I may well be wrong but... This whole line of questioning has that "homework assignment" smell to it. The initial question was _highly_ school-related: > I need to have some template doing the jobs of an > ordinary BST (Binary Search Tree). Nothing that fancy, > but something at the level we all have been educated > in CS1/FCS1, or similar courses. Does boosts > repository contain such an object? The utter lack of background detail leads me to believe that this is just a toy problem... a homework assignment. And then there's the yahoo email address... most proffesional programmers have @mybusiness addresses, though that doesn't mean everyone here is a proffesional. Oh, and the final bit of oddness: > Why don't I write it myself? Simply, because I want to > optimise the time! How is waiting a week or so for some mailing list to hand you an answer "optimizing the time"? This has just been bothering me, I felt the need to speak out. If I'm wrong, then I offer my heartfelt appoligies. This may be what Mr. Hyslop was trying to dig at, I'm just not a patient or subtle person. And I don't mind appologizing for my mistakes (lots of practice, as you might imaging with this sort of behavior). --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typdef std::disclaimer<Cardiff> Discard;

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Threads Library
by Brian Plummer 09 Jun '03

09 Jun '03

Atomic operations (atomic_add, atomic_subtract etc) are not handled in the Boost Threads library. My guess is that this is because this cannot be accomplished, based on what I know about this topic (which isn't too much), in a portable way. Is this the reason? If not, having these operations in the Threads library would be a big benefit. Thanks, Brian

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counted_base vs. sp_counted_base - boost 1.30.0 functionality deprecated
by Anders Hybertz 09 Jun '03

09 Jun '03

Hi Up to and including version 1.29.0 of the boost library I had an object which inherited from boost::counted_base, and could actually within that object control when it should be deleted. The object spawned a thread which was listening on a queue, when there was pushed an shutdown message on the queue, I could safely delete the object. In boost 1.30.0 the counted_base changed name and namespace to boost::detail::sp_counted_base, but the way it works also changed - so now my object's destructor is called whenever it's going out of scope - which I don't want. Any ideas - or should I provide a small sandbox example Thanks in advance Anders Hybertz

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[crc] Simple example please
by Alex Henderson 09 Jun '03

09 Jun '03

Hi, I'd like to calculate a value for a cyclic redundancy check (crc) for a number of files. This isn't going to be transmitted anywhere, I simply want to compare the values to see whether the files are exactly the same. I know I can simply check byte for byte, but I've got a few thousand files and it's easier to calculate the crc for each and see whether any are the same first. I've looked at the crc library, but can't get my head round the example. It seems to test the library rather than show how its used. I'm after something like std::vector<char> MyStream1; // the whole file (about 500kb) boost::SomeCRCTypeThatIsOptimisedForSafetyAndLargeishBlocks<???> x; long = x.checkme(MyStream1); Could someone please point me to some code where a simple example is detailed? Thanks, Alex

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confused by ublas submatrix assignment
by cerenoc 08 Jun '03

08 Jun '03

Hi, I am new to this and am confused by the (sub)matrix operations and also not up on the math nomenclature this group is using such as slices and strides. I am trying a reasonably simple operation of assigning a vector v(2) to a submatrix (3,3). For example, in matlab notation: m = 0 1 2 3 4 5 6 7 8 v = 15 16 m(2, 1:2) = v resulting in: m = 0 1 2 15 16 5 6 7 8 What is the best way to do this with ublas? I suppose I need to convert the vector into another type first, but which one - a slice, a range? I tried both with no success. Thanks a lot, Julian

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uBLA performance
by Matt Hurd 07 Jun '03

07 Jun '03

Hi, Ran off a simple test of the uBLA performance for sqare matrix multiplication. Looks quite good. Put in Intels Math Kernel Library for good measure using uBLA as the data holder but with a call to dgemm. Do you think these are the kind of numbers I should be expecting? Numbers below. Added a chart to the files section http://groups.yahoo.com/group/Boost-Users/files/ called uBLA Performance.pdf Used head of CVS from today. Regards, Matthew Hurd ___________________________________________ Figures in the raw: Matrix Size intel7.1 vc7.0 mingw intel_mkl6.0_vc7.0 ___________________________________________ 1 2 2 2 1 2 13 12 13 11 3 32 30 34 31 4 51 46 59 70 5 67 59 85 109 7 70 78 92 180 9 85 94 113 262 12 99 115 139 304 16 110 131 159 362 20 118 127 178 355 26 125 135 196 334 33 132 148 209 390 42 134 158 217 389 53 130 163 228 451 67 133 171 233 459 84 138 177 241 467 105 133 176 239 473 132 133 178 241 468 166 106 174 233 448 208 90 148 196 445 261 40 63 63 427 327 24 43 45 434 409 24 44 45 421 512 11 12 12 404 640 12 12 12 459 800 36 38 38 455 1000 36 37 38 448 ___________________________________________

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Newbie query: no "deamon" thread?
by dick.bridges＠tais.com 06 Jun '03

06 Jun '03

I need to spawn worker threads that simply perform a task and exit. All the examples I can find seem to use join() to cleanup the thread resources from another thread. Isn't there some way to declare worker threads so that they "do the right thing" as they exit the thread function? TIA

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[BGL] bad edge iterator range returned by boost::out_edges(v,g)?
by Chris Russell 06 Jun '03

06 Jun '03

This is weird... I'm still using BGL from Boost 1_29_0 (which may be an issue?). Anyway, I've got a graph as so: typedef boost::property<vertex_forest_property_t, CProteinCircuitForestVertexProperty, boost::property<boost::vertex_index_t, long, boost::property<boost::vertex_color_t, boost::default_color_type> > > forest_vertex_property_maps_declaration_t; typedef boost::adjacency_list<boost::listS /*edges*/, boost::listS /*vertices*/, boost::bidirectionalS, forest_vertex_property_maps_declaration_t> forest_graph_t; I've done a lot with this class, including all kinds of edge traversal. Now suddenly I have a case where boost::out_edges seems to be returning an invalid iterator range. I'm absolutely certain the vertex descriptor is correct, boost::out_degree returns the expected number of out edges, however I fault inside my access loop because the iterator has gone out of range.... typedef boost::graph_traits<forest_graph_t>::vertex_descriptor forest_vertex_descriptor_t; typedef boost::graph_traits<forest_graph_t>::vertex_descriptor forest_vertex_descriptor_t; typedef boost::graph_traits<forest_graph_t>::edges_size_type forest_edges_size_t; typedef boost::graph_traits<forest_graph_t>::out_edge_iterator forest_edge_out_iterator_t; forest_edge_out_iterator_t edgeoutiterBegin, edgeoutiterEnd, edgeoutiterCurrent; boost::tie(edgeoutiterBegin, edgeoutiterEnd) = boost::out_edges(v/*forest_vertex_descriptor_t*/,g/*forest_graph_t); for (edgeoutiterCurrent = edgeoutiterBegin; edgeoutiterCurrent != edgeoutiterEnd ; ++edgeoutiterCurrent) { // works fine through the expected out edges - faults because the loop fails to terminate forest_vertex_descriptor_t vertexTarget = boost::target(*edgeoutiterCurrent, g); } // end for Any suggestions would be greatly appreciated. I'm really scratching my head because I've done this exact operation in several other places in the algorithm and it works just fine.... TIA - Chris

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Tree Object Needed!
by Hossein Haeri 06 Jun '03

06 Jun '03

Dear all, I need to have some template doing the jobs of an ordinary BST (Binary Search Tree). Nothing that fancy, but something at the level we all have been educated in CS1/FCS1, or similar courses. Does boosts repository contain such an object? Why don't I write it myself? Simply, because I want to optimise the time! Thank you, --Hossein __________________________________ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com

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boost::filesystem help needed
by ericd 06 Jun '03

06 Jun '03

Hi all, I have compiled the boost::filesystem using bjam and that seemed to have gone well. The first question I have concerning this is if it is normal NOT to have a libfilesystem.so. I can only find the libfilesystem.a. The path where this lives is quite deep. /usr/local/boost_1_30_0/boost/libs/filesystem/build/bin/libboost_filesystem.a/gcc/release/runtime-link-dynamic and /usr/local/boost_1_30_0/boost/libs/filesystem/build/bin/libboost_filesystem.a/gcc/debug/runtime-link-dynamic My current setup is an Ultra 80 running Solaris 9. I use both gcc version 3.2.3 for compiling and linking. The version of Boost is 1.30.0. For my second question. Having this built, I have tried to use it but come up with undefined symbols The output follows: g++ -lboost_filesystem -o io main.o Undefined first referenced symbol in file boost::filesystem::path::native_directory_string() constmain.o boost::filesystem::path::native_file_string() constmain.o boost::filesystem::path::path[in-charge](char const*, boost::filesystem::path_fo rmat)main.o boost::filesystem::directory_iterator::directory_iterator[in-charge](boost::file system::path const&)main.o boost::filesystem::path::leaf() constmain.o boost::filesystem::initial_path() main.o boost::filesystem::system_complete(boost::filesystem::path const&)main.o boost::filesystem::directory_iterator::m_inc() main.o boost::filesystem::directory_iterator::directory_iterator[in-charge]()main.o boost::filesystem::is_directory(boost::filesystem::path const&)main.o boost::filesystem::directory_iterator::m_deref() constmain.o boost::filesystem::exists(boost::filesystem::path const&)main.o ld: fatal: Symbol referencing errors. No output written to io Now I am quite sure that the path to the filesystem library is correct and therefore, cannot figure out why this will not link properly. But then again, I might be mistaken. Here is a snip from my makefile. On second thought, here is the whole thing: SHELL = /bin/sh # PROJECTLOCATION = /home/ericd/Projects/FileSystemTest EXEDIR = $(PROJECTLOCATION)/bin # LIBPATH = -L/usr/local/lib # Sources, includes and the likes.. also output names SELFTESTSRC = main.cpp INCLUDE = -I/usr/local/boost_1_30_0/boost SELFTEST = io # ifeq (,$(filter _%,$(notdir $(CURDIR)))) include target.mk else VPATH = $(SRCDIR) # Compiler Linker Defines for test exe CXX = g++ LD = g++ DEBUG = -g CXXSELFTEST = $(DEBUG) $(INCLUDE) -c -O2 -W -Wall -Wno-unused -Wno-multichar -fexceptions LDSELFTESTFLAGS = -lboost_filesystem # Building options all: test test: CXXFLAGS = $(CXXSELFTEST) test: $(SELFTEST) # SELFTESTOBJ = $(SELFTESTSRC:.cpp=.o) # pull in dependency info for *existing* .o files -include $(SELFTESTOBJ:.o=.d) # Compile and generate dependency info %.o: %.cpp $(CXX) $(CXXFLAGS) -MMD $(SRCDIR)/$*.cpp -o $@ @mv -f $*.d $*.d.tmp @sed -e 's|.*:|$*.o:|' < $*.d.tmp > $*.d @sed -e 's/.*://' -e 's/\\$$//' < $*.d.tmp | fmt -1 | sed -e 's/^ *//' -e 's/$$/:/' >> $*.d @rm -f $*.d.tmp # Link all Object Files and copy them over to our bin $(SELFTEST): $(SELFTESTOBJ) $(LD) $(LDSELFTESTFLAGS) -o $(SELFTEST) $(SELFTESTOBJ) cp $(SELFTEST) $(EXEDIR)/$(SELFTEST) # endif I have added in my .cshrc at the LD_LIBRARY_PATH var the location of my filesystem library. Being relatively new to gcc my guess is that something has to be wrong with the flags I give it. I did do an nm -C libfilesystem.a and all missing symbols reported by the link are there. Does anyone have any clue as to why this aint working? Thanks in advance for your input, Eric

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Re: Can't find a clear example of disallowing parallel edges
by Arthur 06 Jun '03

06 Jun '03

The section pointed out says to use a set instead of list if you don't want parallel edges. I guess I was hoping to have parallel edge removal using a list (insertion/deletion consideration appear to make the list a better choice for me). A --- In Boost-Users(a)yahoogroups.com, "Arthur" <arthurc@t...> wrote: > Saw that... didn't help. Too many program fragments and not enough > complete code examples IMHO. I guess I'll just have to figure it out > the hard way. > > A > > --- In Boost-Users(a)yahoogroups.com, "Chris Russell" <cdr@e...> wrote: > > Arthur, > > > > see the following: > > > > http://www.boost.org/libs/graph/doc/using_adjacency_list.html > > ^- see specifically "Choosing the EdgeList type".. Sequence vs. > > AssociativeContainer vs. UniqueAssociativeContainer > > > > http://cvs.sourceforge.net/cgi- > bin/viewcvs.cgi/boost/boost/libs/graph/example/container_gen.cpp? > rev=1.1&content-type=text/vnd.viewcvs-markup > > ^- container_gen.cpp example > > > > HTH - Chris > > > > > > > > "Arthur" <arthurc@t...> wrote in message > > news:bbnl0i+k498@e... > > > I'm trying to use this graph class without detailed reading. I > can't > > > find a decent, clear example of doing this. I have a simple > graph: > > > > > > typedef adjacency_list<list, listS, bidirectionalS> Graph; > > > > > > What do I do to prevent parallel edges to be inserted? > > > > > > Thanks for any help offered, > > > Arthur

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How do I use Boost with the Visual Studio IDE?
by Ken Fogel 06 Jun '03

06 Jun '03

I can get the threads examples to compile and link with bjam but I am unable to get it to work from within the Visual Studio IDE (versions 6 or 7.1). Does anyone have a basic project structure that could be used in the IDE for threads? I am writing console applications rather than GUI apps.

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Re: [Boost-Users] Re: Newbie query: no "deamon" thread?
by dick.bridges＠tais.com 06 Jun '03

06 Jun '03

I was asking this question for someone else. Except for trivial programs, I always use one form of pool or another. Spend a lot of time reading "pattern" books. To tell the truth, I have no idea what the "real" cost of creating & killing threads is for the various OSs. I just treat it like small object memory allocation: if you don't have a custom allocator, try to avoid doing it. ;) Mark Sizer <yg-boost-users@m To: boost-users(a)yahoogroups.com .gmane.org> cc: Sent by: news Subject: [Boost-Users] Re: Newbie query: no "deamon" thread? <news(a)main.gmane. org> 06/05/2003 05:23 PM Please respond to Boost-Users BTW: Is there enough of a penalty to creating threads that a thread pool should be used rather than creating them on-demand? I'm curious because I'm using a pool pulling from a work queue. - Mark P.S. I realize "enough" is a bit vague. Mark Sizer wrote: > What is "the right thing"? > > You don't HAVE to join(). The creating thread will just keep going if > you don't. If you join, it waits. > > If you're passing ownership (e.g. delete responsibility) across thread > boundaries, you have to be careful, but that doesn't have much to do > with join(). > > After starting the thread, you can use a condtional in the creator to > wait for the thread to "get going" and accept ownership, sort of a > "started()" rather than an "ended()", like join(). Or you can flip it > around and have the started thread wait on the conditional whilst the > creator thread continues to use what will eventually be given to the thread. > > Is that at all helpful? > > - Mark > > dick.bridges(a)tais.com wrote: > > >>I need to spawn worker threads that simply perform a task and exit. All >>the examples I can find seem to use join() to cleanup the thread resources >>from another thread. Isn't there some way to declare worker threads so >>that they "do the right thing" as they exit the thread function? >> >>TIA >> >> >> >>Info: <http://www.boost.org> >>Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> >>Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> >> >> >>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ >> >> >> >> >> > > > > > > Info: <http://www.boost.org> > Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> > Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > > Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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[BGL] vistor works w/DFS, won't compile w/DFV - appearent concept check violation - but why?
by Chris Russell 06 Jun '03

06 Jun '03

I initially posted this to the devel list. Apologies for reposting it to the user list but this is really a library _user_ question - not a devel question. I've now screwed around with this for the better part of a day and haven't figured it out. I'm off re-reading BGL book 2.5 concept checking explanation but I'll still baffled. I will post the compiler errors if anyone is willing to give me hand understanding why I can't get what I believe should be quite a simple case working. Here's the problem statement: --- I've got a struct derived from boost::default_dfs_visitor that I've been using w/out any problems in an invocation of boost::depth_first_search. The call that works looks like: boost::depth_first_search(g, boost::visitor(MyDfsVisitor)); ^- NP. compiles and executes fine. Now I'm trying to use the exact same visitor in the context of a boost::depth_first_visit call (so I can set the starting vertex). But I'm having big troubles. I tried this: boost::depth_first_visit(g, s, boost::vistor(MyDfsVisitor), boost::get(boost::vertex_color, g)) // note I'm using an internal, default color map ^- this won't compile. It seems to be balking duing Jeremy's visitor concept checking? The compiler errors are extensive and it looks like none of the visitor methods are being correctly identified. (e.g. missing vis.InitializeVertex ... etc. etc..) p.172 of the BGL book on DFS notes: IN: visitor(DFSVisitor vis) whereas p.175 on DFV notes: IN: DFSVisitor visitor. So I guessed and tried this syntax: boost:depth_first_visit(g, s, MyDfsVisitor, boost::get(boost::vertex_color, g)) ^- this compiles. But I'm getting an exception fault during visitor invocation somewhere deep inside the the RTL. Can anyone enlighten me about what's going on here? What exactly does boost::vistor(X) do? And why is it needed on the DFS call, and apparently rejected in the DFV call? Any help would be sincerely appreciated. - Regards Chris

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uBLAS file io
by cerenoc 06 Jun '03

06 Jun '03

Hi, I'm new to BOOST/uBLAS. I would like to use uBLAS on a matrix that I read in from a file. How does file io work with uBLAS? What are the specific formats? If someone could provide a small example it would be much appreciated. Thank you, Julian

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Warning - Format library adds 48 KB
by Tom 05 Jun '03

05 Jun '03

Boost::Format adds 36KB (VC7.1) or 48 KB (VC6) to my release executable! Details: Take one C++ Win32 application which uses both MFC and the VC STL, but not std::string. Optimizations are set for minimum size. In VC7.1 the release exe is 552 KB. Add std::string, adds 4 KB. Add boost::format, adds another 36 KB. (For each I just added one statement.) For VC6 SP5 the release exe is also 552 KB. Add just the '#include's for string & format libraries, adds 20 KB (VC7.1 didn't do this). Add std::string and boost::format, adds another 32 KB. Total added by format is (20 + 32 - 4) = 48. This is not acceptable for my application. Is there a better way to use C-style printf statements with std::string? Tom. (Thanks to Gmane for making this list usenet accessible!)

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Can't find a clear example of disallowing parallel edges
by Arthur 05 Jun '03

05 Jun '03

I'm trying to use this graph class without detailed reading. I can't find a decent, clear example of doing this. I have a simple graph: typedef adjacency_list<list, listS, bidirectionalS> Graph; What do I do to prevent parallel edges to be inserted? Thanks for any help offered, Arthur

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