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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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