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ublas identity_matrix problem
by Heiko Bauke 08 Sep '04

08 Sep '04

Dear all, I discovered a problem in ublas identity_matrix class. I am doing linear algebra in finite fields. So my matrices contain no floats nor doubles. Instead I use some class that behaves like a number but does arithmetic in a finite field. Class instances are contructable by int, but _not_ default constructable by int. I don't want to have this. In matrix.hpp one finds the lines template<class T> typename identity_matrix<T>::value_type identity_matrix<T>::zero_=0; template<class T> typename identity_matrix<T>::value_type identity_matrix<T>::one_=1; These lines are problematic and the reason why my number class works not with the identity_matrix class. I think these lines should by changed into template<class T> typename identity_matrix<T>::value_type identity_matrix<T>::zero_=T(0); template<class T> typename identity_matrix<T>::value_type identity_matrix<T>::one_=T(1); to make the ublas code more general. with regards Heiko -- -- Gute Sitten haben für die Gesellschaft mehr Wert als alle -- Berechnungen Newtons. (Friedrich II., der Große, 1712-1786) -- Supercomputing in Magdeburg @ http://tina.nat.uni-magdeburg.de -- Heiko Bauke @ http://www.uni-magdeburg.de/bauke

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How to remove custom property map from graph dynamically ?
by Raj 08 Sep '04

08 Sep '04

Hi, I have an adjacency list graph with three custom property maps attached. At some point during the run of the program, I would like to remove two of those maps from the graph. Is it possible ? How can I do it ? Thanks in advance Raja

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RE: [Boost-users] Re: statically linking to Boost.Threads with msvc7
by Simmons, Aaron 08 Sep '04

08 Sep '04

> In Boost release 1.31, the Boost.Threads library doesn't support static > linking. This limitation will be removed in the next release (coming > soon) for: > > a) anyone using the pthreads implementation of Boost.Threads > b) anyone using Visual C++ on Win32 > > Hopefully it will be removed for other Win32 compilers in the future. How was the TSS problem solved for win32-threads? What's the ETA for the next version? Thanks, aaron

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macro m4 for boost
by Thomas Lemaire 08 Sep '04

08 Sep '04

Hi boost-users, I am looking for a macro m4 (used by autoconf) that automatically detects boost installation directory. Has anybody got it ? thomas

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dynamically created program options
by Rodolfo Schulz de Lima 08 Sep '04

08 Sep '04

Hi, I wonder if it's possible to handle dynamically created program options with boost::program_options. For instance: I have a config file that specifies configure options for dynamic loaded modules in my project. So the cfg file would be: [module.foo1] module_file = foo.so listen_port = 564 enabled = true [module.foo2] module_file = foo.so listen_port = 565 enabled = false [module.bar1] module_file = bar.so listen_port = 145 enabled = true As can be seen, foo1, foo2 and bar1 names are defined by the user in the configure file, and the program doesn't know about them before parsing the configuration. But if we parse that (somehow), an exception saying that the option "module.foo1.module_file" is invalid will be thrown. Can I manage the options_description "on the fly"? Another less complicated situation would be something like this: modules = foo1 foo2 bar1 [module.foo1] . . . [module.foo2] . . . [module.bar1] . . . So when parsing the "modules" option, we would know the new options name and it would be a matter of appending more option descriptions to the object. Regards, rod

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Min-Cut o Max-Flow in a graph?
by Daniele Carlucci 08 Sep '04

08 Sep '04

Hi, How can I find the min-cut, or the max-flow in a graph with all the costs of edges equal one? Thanks Daniele

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Comiling Boost with VC++.net
by Andreas Kempf 07 Sep '04

07 Sep '04

My IDE for C++ is VC++.net I heard that it is impossible to compile Boost with its compiler. I replaced the compiler with the VC++.net 2003 Toolkit Compiler, but it still doesn't work. Can anyone help me compiling with the VC++.net 2003 Toolkit?

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RE: [Boost-users] signal slot flexibility
by Frank Maddin 07 Sep '04

07 Sep '04

Ahh, so now I'm able to do such things as this. Hello* h_ptr = new Hello(); World* w_ptr = new World(); typedef boost::signal< int (int, float) > IntFloatSignal; IntFloatSignal sig; sig.connect(boost::bind(&Hello::alternate_int_float, h_ptr, _1, _2)); sig.connect(boost::bind(&World::alternate_int_float, w_ptr, _1, _2)); float temp = 0.0f; sig(1, temp); > I don't see much benefit to extra (explicit) level of indirection here. > Most slots are short bind expressions that don't ever need to be > revisited, so it seems that it could be a bit challenging to determine > where some slots should reside: always in the class containing the > member function that is called (assuming one only uses member > functions!)? I guess I was thinking that since nothing is done with inheritance, it provides less opportunity to do things that might get you into trouble. If I've a hierarchy that looks something like this: BaseObject SimpleObject : BaseObject, signals::trackable ComplexObject : SimpleObject ReallyComplexObject : ComplexObject, signals::trackable where a SimpleObject can get a signal of one type and a ReallyComplexObject object can get another, is trackable inheritance ok with this or is there some other recommended method? Thanks again, Frank -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Doug Gregor Sent: Tuesday, September 07, 2004 2:38 PM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] signal slot flexibility On Sep 7, 2004, at 1:36 PM, Frank Maddin wrote: > If I add a function to both Hello and World, from the "Hello World" > example, called alternate() and set up signals like so: > > > > boost::signal<void (Hello*) > sig_h; > > boost::signal< void (World*) > sig_w; > > > > sig_h.connect(boost::mem_fn(&Hello::alternate)); > > sig_w.connect(boost::mem_fn(&World::alternate)); > > > > I have to define two different signals since the object type is part > of the signal definition. Is there an easy way to get a single signal > to call the alternate() function of both Hello and World? Without Hello and World being related (e.g., sharing a base class declaring a virtual "alternate" function), I don't see a way. Still, when you call these signals you have to know whether you have a "Hello" in hand or a "World"; perhaps you wanted to store the "Hello" and "World" objects within the signal, and pass it no arguments? For instance, boost::signal<void()> sig; sig.connect(boost::bind(&Hello::alternate, &my_hello)); sig.connect(boost::bind(&World::alternate, &my_world)); > I recently found this signal slot solution. > http://www.codeproject.com/cpp/ElmueSignalsandSlots.asp > > There is an extra level of indirection here, in that you define a slot > that points to the function. I'd be interested to see what people on > this forum think about this solution. If I understand things > correctly, this solution doesn't seem to fit into the categories > listed in the "Choice of Slot Definitions" docs. I don't see much benefit to extra (explicit) level of indirection here. Most slots are short bind expressions that don't ever need to be revisited, so it seems that it could be a bit challenging to determine where some slots should reside: always in the class containing the member function that is called (assuming one only uses member functions!)? > Also a general signal slot question. What are the main reasons why > developers don't use an inherited pure interface for every callback > type? A signal would be a template class with a list of pointers to > the interface and some methods to operate on the list. Not flexible > enough? You often want only one event out of five, so it's a pain to drop in all of the stubs needed to ignore the other events. Also, you don't get a choice of names to use: if the writer of the interface says it's "on_click", you must write a function named "on_click" even though you'd rather write something like "submit_current_query" that describes the action taken when the event fires, not the event itself (which is essentially irrelevant). > Doesn't scale well to larger uses? Time spent calling virtual > functions? I saw this in the boost signal docs that might apply - > "the use of a large number of small adaptor classes containing virtual > functions has been found to cause an unacceptable increase in the size > of executables (polymorphic class types require more code than > non-polymorphic types)". This is more of an implementation detail; using function pointers instead of virtual functions tends to reduce the amount of code generated for libraries such as Boost.Signals or Boost.Function. Doug _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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signal slot flexibility
by Frank Maddin 07 Sep '04

07 Sep '04

Hi, I have some questions about signals. If I add a function to both Hello and World, from the "Hello World" example, called alternate() and set up signals like so: boost::signal<void (Hello*) > sig_h; boost::signal< void (World*) > sig_w; sig_h.connect(boost::mem_fn(&Hello::alternate)); sig_w.connect(boost::mem_fn(&World::alternate)); I have to define two different signals since the object type is part of the signal definition. Is there an easy way to get a single signal to call the alternate() function of both Hello and World? I recently found this signal slot solution. http://www.codeproject.com/cpp/ElmueSignalsandSlots.asp There is an extra level of indirection here, in that you define a slot that points to the function. I'd be interested to see what people on this forum think about this solution. If I understand things correctly, this solution doesn't seem to fit into the categories listed in the "Choice of Slot Definitions" docs. Also a general signal slot question. What are the main reasons why developers don't use an inherited pure interface for every callback type? A signal would be a template class with a list of pointers to the interface and some methods to operate on the list. Not flexible enough? Doesn't scale well to larger uses? Time spent calling virtual functions? I saw this in the boost signal docs that might apply - "the use of a large number of small adaptor classes containing virtual functions has been found to cause an unacceptable increase in the size of executables (polymorphic class types require more code than non-polymorphic types)". Thanks Frank

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Re: [Boost-users] bjam with mingw
by Brewer, Christopher 07 Sep '04

07 Sep '04

Angus- I had similar problems with bjam under MinGW. By experimentation, I discovered that I could make bjam work under MinGW by moving it from it's previous location at 'c:/msys/1.0/bin' to 'c:/msys/1.0/mingw/bin'. FYI, you can find this thread starting at Boost-users Digest, Vol 250, Issue 1, and ending (successully :) at Boost-users Digest, Vol 253, Issue 1. HTH, Chris Brewer

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bjam with mingw
by Angus Leeming 07 Sep '04

07 Sep '04

Please forgive the newbie questions, but I am trying and failing to build boost with MinGW. I've grabbed the CVS sources of boost from the sourceforge anonymous mirror. I've installed MinGW and MinSYS. The MinGW tools are in my path. From the MinSYS console: $ cd ~/boostcvs $ which which c++ /mingw/bin/c++ $ c++ --version c++.exe (GCC) 3.2.3 (mingw special 20030504-1) Just to check that the tools are working: $ cd libs/spirit/phoenix/test $ c++ -I$HOME/boostcvs -o new_test new_test.cpp $ ./new_test /////////////////////////////////////////////////////////////////////////////// Tests concluded SUCCESS!!! /////////////////////////////////////////////////////////////////////////////// Now trying to do something similar using bjam: $ cd ~/boostcvs/libs/test/build $ bjam '-sTOOLS=mgw' CALL "C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\bin\VCVARS32.BAT" >nul "C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\bin\cl" /Zm800 -nologo /EHsc -c -DBOOST_TEST_NO_AUTO_LINK=1 /Z7 /Od /Ob0 /EHsc /GR /MTd /Op /Zc:forScope /Zc:wchar_t -I"..\..\..\bin\boost\libs\test\build" -I"d:\MinSYS\1.0\home\Angus\boost_cvs" -Fo"..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\unit_test_main.obj" -Tp"d:\MinSYS\1.0\home\Angus\boost_cvs\libs\test\build\../src/unit_test_main.cpp" ...failed vc-C++ ..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\unit_test_main.obj... vc-C++ ..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\supplied_log_formatters.obj The system cannot find the path specified. The system cannot find the path specified. [ snip all other, similar messages ] For the life of me I can't see why bjam is trying to build the VC++ target. I can't even run $ bjam --help because it just does the same thing, trying and failing to build stuff with VC++. I have also tried running from the top level boost directory and with the '-sMINGW_ROOT_DIRECTORY=/d/mingw' command line option to bjam, all to no avail. (From my understanding of the docs at http://www.boost.org/tools/build/v1/mingw-tools.html, that shouldn't be necessary.) I have changed the TOOLS name to 'mingw' rather than 'mgw'. Again , no dice. Finally, in desperation, opening up a DOS prompt and repeating the exercise. Nope. Same result. Can anyone help me out? Regards, Angus

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RE: [Boost-users] output stream cloning?
by Ben Hutchings 07 Sep '04

07 Sep '04

Jon Biggar <jon(a)levanta.com> wrote: > Is there any package in Boost (or upcoming in the Boost review queue) > that would let me create an output stream that clones its output to > one or more underlying output streams? Jonathan Turkanis's Iostream library, which is currently under review and has been mostly positively received, seems to make it pretty trivial to write such a thing - see <http://lists.boost.org/MailArchives/boost/msg69799.php> and <http://lists.boost.org/MailArchives/boost/msg69827.php>.

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problem with CVS Boost.Python with MSVC
by Stephen D Evans 07 Sep '04

07 Sep '04

The CVS change to boost/boost/python/detail/prefix.hpp from revision 1.3 to 1.4 has obviated the effect of boost/boost/python/detail/wrap_python.hpp in _DEBUG when compiling with MSVC. Python now forces the debug library as if BOOST_DEBUG_PYTHON is permanently in effect. Revision 1.3 does not exhibit this problem. The added #include <pyconfig.h> is the cause. Stephen D Evans

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dangerous use of boost::bind
by Gast 128 07 Sep '04

07 Sep '04

Dear all, In my work I use the boost libraries quite frequently, especially boost::bind to create function objects. However its use is not as transparent as I hoped for. Especially using functions in boost bind with signatures returning const& can give unpredictable results. For example: struct KX { KX (int i); //etc. }; typedef std::pair<int, KX> pair_t; pair_t do_kx_pair(int i) { return std::make_pair(i, KX(i)); } //following will go wrong: KX x = boost::bind(&pair_t::second, boost::bind(&do_kx_pair, i))(); The last line compiles on Visual .NET 2003 without any warning (even on level 4). However after spending two days in boost bind source code, I could see that it actually returns const& to a temporary created by boost bind. The reason for this is that arguments are copied by value, and thus functions with const & (or in this case pointer to member) can return then const & from temporaries. Is there no way that at least boost::bind could issue a compiler warning? Because now I have to think deep before I create a nested boost bind construction. For example the following construction is not wrong; the const & is again taken from a temporary which boost::bind holds, but this is destroyed after the expression: KX x = boost::bind(&pair_t::second, do_kx_pair(i))(); If this is not solvable, perhaps it's a good idea to include this case in the documentation. Wkr, me (btw boost::bind is a great improvement over the std::mem_fun and std::bind1st etc.)

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Problems with boost::format and Visual C++ 7.0
by Tom Quarendon 07 Sep '04

07 Sep '04

I have trouble compiling code that makes use of the boost::format library. In particular I get compile errors from basic_format::operator= method (line 90 format_implementation.hpp). If I change the body to look like if(this == &x) return *this; basic_format<Ch, Tr> x1(x); // These 2 lines used x1.swap(*this); // to be 1 return *this; It compiles. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.737 / Virus Database: 491 - Release Date: 11/08/2004

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output stream cloning?
by Jon Biggar 07 Sep '04

07 Sep '04

Is there any package in Boost (or upcoming in the Boost review queue) that would let me create an output stream that clones its output to one or more underlying output streams? -- Jon Biggar Levanta Inc jon(a)levanta.com

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Directory_Iterator causes MFC App to Freeze
by RYAN ROSARIO 06 Sep '04

06 Sep '04

Hi, I am writing an MFC program in MSVC7 that must pass a path from one dialog box to another upon pressing a button. I attempt to pass the path to the next dialog by using a directory iterator: fs::directory_iterator startIt(scanPath); (***) where scanPath is an object of type path. PICtoolProgressWnd temp(this,startIt); I pass the iterator into the constructor for the second dialog. When I attempt to run this program, my program just hangs after clicking the button and I cannot exit it. The second dialog never appears. The only way out is to Alt-Ctrl-Delete out of the program. The only other clue given is that when the program freezes, the "xstring" file opens with a green arrow pointing at what appears to be a definition of operator= or something of that sort. I have commented out practically all of my code in the button click event handler and determined that when the iterator is declared, (***) above, the program freezes. When this line is commented out, the program responds. What could I be doing wrong?? Below is some more code: //Creating the dialog if ( temp.DoModal() == IDOK) { //Display results. } else { //Are you sure you wish to cancel this process? } //Second dialog constructor. PICtoolProgressWnd::PICtoolProgressWnd(CWnd* pParent /*=NULL*/, fs::directory_iterator start) : CDialog(PICtoolProgressWnd::IDD, pParent) { startScanPath = start; } //startScanPath is a member variable of type fs::directory_iterator. Your help is greatly appreciated. Thanks in Advance, Ryan --------------------------------- Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard.

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Using MPL to write is_derived_from_std_basic_ostream
by Angus Leeming 06 Sep '04

06 Sep '04

I'm trying to ascertain whether a given class is, or is derived from, std::basic_ostream, but I've ground to a halt. The attached code successfully reports those classes that do derive from std::basic_ostream but fails to compile when I test std::string, bool, char etc. I can see what is going wrong, but have run out of ideas about how to fix it. I'm also painfully aware that my attempts are just plain ugly. Can someone show me the way forward? Regards, Angus

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global stream manipulators for the format library
by Justin Findlay 05 Sep '04

05 Sep '04

I've got some code that uses the format library to format output, not out of necessity, but rather out of a wanton enjoyment derived from using the syntax, having lately (relatively) discovered boost, prefering the boost::format simple syntax to the posix printf and std::ostringstream flavored solutions. The "problem" I have is that for the output of every double, I have to specify the precision: int main() { cout << setprecision(18); cout << format("Bunner p' air: %1% torr\t\tN$_2$: %2% torr\n" " C air: %3%\t\tN$_2$: %4%") % group(setprecision(18), bunner::air::pp_av) % group(setprecision(18), bunner::N2::pp_av) % group(setprecision(18), bunner::air::c_av) % group(setprecision(18), bunner::N2::c_av) << endl; //... return 0; } Is there a graceful solution, or am I using this library beyond what it was intended for? Something like the following naturally suggests itself, but I don't think it is standard compliant: the constructor doesn't seem to like using a static object, actually the linker couldn't find the 'prmanip' object. class Fmt { public: Fmt() { cout << "duh" << endl << prmanip << constants::pi << endl; } static std::_Setprecision setpr(const int&pr) { prmanip = std::setprecision(pr); return std::setprecision(pr); } static std::_Setprecision prmanip; }; int main() { cout << setprecision(18); Fmt::setpr(18); //... Justin

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Problem using Boost Signals HPP file
by Brian Braatz 05 Sep '04

05 Sep '04

I am using vc7.1 MS Visual Studio 2003. I have tried using the boost signals (boost/signal.hpp) library in both my application and a Visual Stuido project file using the signal_test.cpp file. (made a blank C++ win32 console app project file- and then added the include dir for boost- I did nothing else). in either case I get: Compiling... signal_test.cpp Linking... LINK : fatal error LNK1104: cannot open file 'libboost_signals-vc71-sgd-1_31.lib' Build log was saved at file://c:\Rmtg\Root\_Common\_Lib\Boost\V_1_31\libs\signals\test\signal_test\signal_test\Debug\BuildLog.htm signal_test - 1 error(s), 0 warning(s) ---------------------- Done ---------------------- Build: 0 succeeded, 1 failed, 0 skipped My project file is quite bare other than pointing to boost as an include dir. I am perplexed on how visual studio is even AWARE of the lib name (since I did not tell it). On the machine I am using, I have not built boost static or dll libs. That would solve my problem, but not completely as what I *need* to do is use the hpp and *not* link to the lib. My questions: has anyone run into this before? Is Boost::signals supposed to work by just being able to #include the hpp? Any thoughts here? (one of those situations where I am really scratching my head). **ANY** thoughts or suggestions greatly appreciated

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generic factory creator
by Stephen torri 04 Sep '04

04 Sep '04

In my example data is passed between objects using a Data_Source. I want to hide the method data is passed from what the value is of the data. So a object receiving it does not need to be concerned with whether the data is coming from a file or database. In my situation I have three data sources for information: a file, memory pointer or database. Each of these data sources can handle a std::string, a Memory_Object, and a Graph_Object type as its internal data structure. The question I want to understand is how to create a generic interface to create the appropriate factory. Here is the table of the possible data source combinations (3 types * 3 sources = 9 possible). So more types and more sources can make creating the right Data_Source an ugly experience for maintaining the code. I don't want to have to have 9 separate functions. ----------------------------------------------------------- | File_Data_Src | Memory_Data_Src | Graph_Data_Src ----------------------------------------------------------------------- std::string | x | x | x ------------------------------------------------------------------------ Memory Obj | x | x | x ------------------------------------------------------------------------ Graph Obj | x | x | x ------------------------------------------------------------------------ At initialization I give a interger the Data_Source_Factory_Creator to represent what kind of factory I want. When a call is made to the Data_Source_Factory_Creator::get_Factory I want the apporpriate factory returned based upon the integer value given during initialization. Right now I get the right compilor error for Data_Source_Factory_Creator::get_Factory() because given Data_Source_Factory is a template class I need to instantiate this template correctly. I don't know how to make this function return a generic type so that I can do: Data_Source_Factory<File_Data_Source>* m_factory = Data_Source_Factory_Creator::get_Factory(); Any ideas? Stephen -- Email: storri(a)torri.org

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Signals - last call
by Georgios Diamantopoulos 04 Sep '04

04 Sep '04

Hello everyone, I have a question concerning signals. I wanted to force one of the callbacks to be called last. Obviously this needs to be done in an agnostic way since the calling function will probably not know how many other callbacks are connected and so on. I could not find anything in the documentation - only about numbered calls. Any ideas? Thanks in advance. Georgios

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Is there a binary serialization class ?
by Raj 03 Sep '04

03 Sep '04

Hi, Is there a binary serialization class in any of the boost file lib ? Also, how do I re-target and compile the boost libraries with the newly released Visual Studio Express edition ( VC 8.0 ) ? Thank in advance. Raja

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How to find min-cut?
by Daniele Carlucci 03 Sep '04

03 Sep '04

Hi, How can I find the min-cut (max-flow) in a graph undirected with all the weights of the edges equal one. Thanks Daniele

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Building boost as part of larger project which also uses jam
by Phillip Seaver 03 Sep '04

03 Sep '04

I want to switch to jam for building our projects and I was wondering how to handle building boost within those projects. Will "subinclude boost" from the directory above it work? Or will I have to use bjam on the boost tree (like a recursive make)? Thanks in advance, Phillip

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