October 2005 - Boost-users - lists.preview.boost.org

[random] spot the stupidity competition
by Nigel Rantor 21 Oct '05

21 Oct '05

Hail all, Thanks for giving us the libraries, now only if we were all smart enough to use them properley the world would be at peace. As it is I've been having some problems with my own code that is wrapped around the random library. I'm playing around with a game I'm making and needed some randomness, games that are predicatble are just a tad boring... I need to generate numbers with lots of different distributions so creating one or two won't really cut it for me, there would have to be hundreds. Instead I went and basically ripped the random_number_generator described under decorators into two flavours and then created a bunch of overloaded functions that used them. The generators use a single real engine, currently mt19937;. Basically, everythnig works fine, except that calling seed( n ) on the engine doesn't effect the generators that hold a ref to it, which I found somewhat bizzare. So, after a few tweaks I ripped out the code and dumped it into a minimal test case and can see that the seed( n ) method works just fine when I pull raw numbers out of the engine, but still doesn't seem to effect the generators I've defined. I'm fairly sure this is my problem but I was wondering if anyone would be good enough to take a peek and tell me why exactly this isn't working. I did have a search on Gmane but couldn't find anything that looked related to my problem. I'm not sure what is the done thing on this list so I've attached source, if you want a makefile then I can oblige but it is a fairly small case. The test program reads in three numbers, the seed to use, the number of numbers to generate and the max to use when generating numbers from a distribution. Feeding it different seeds makes the raw number change, but not the others. I have also included the output of two runs to show you what I mean. TIA, N seed : 42 num : 10 max : 1000 seeded rng... 10 raw numbers from rng 1608637542 3421126067 4083286876 787846414 3143890026 3348747335 2571218620 2563451924 670094950 1914837113 10 random integers using rng 795 926 666 119 485 903 904 335 227 185 seed : 727364 num : 10 max : 1000 seeded rng... 10 raw numbers from rng 3240174879 3269238853 3044917573 2953574107 2463698974 2129367301 2064401652 2079989189 3644954707 1971100779 10 random integers using rng 795 926 666 119 485 903 904 335 227 185 #include "random.h" int random_num( int max ) { return int_gen( max ); } int random_num( int min, int max ) { return min + random_num( max ); } long random_num( long max ) { return long_gen( max ); } long random_num( long min, long max ) { return min + random_num( max ); } float random_num( float max ) { return float_gen( max ); } float random_num( float min, float max ) { return min + random_num( max ); } double random_num( double max ) { return double_gen( max ); } double random_num( double min, double max ) { return min + random_num( max ); } #ifndef RANDOM_H #define RANDOM_H #include <boost/random.hpp> using namespace boost; typedef mt19937 rng_type; template<class RNG, class IntType = long> class integer_random_number_generator { public: typedef RNG base_type; typedef IntType argument_type; typedef IntType result_type; integer_random_number_generator( base_type& rng ) : _rng( rng ) {} result_type operator()( argument_type n ) { typedef uniform_int<IntType> dist_type; return variate_generator<base_type&, dist_type>(_rng, dist_type(0, n-1))(); } private: base_type& _rng; }; template<class RNG, class RealType = double> class real_random_number_generator { public: typedef RNG base_type; typedef RealType argument_type; typedef RealType result_type; real_random_number_generator( base_type& rng ) : _rng( rng ) {} result_type operator()( argument_type n ) { typedef uniform_real<RealType> dist_type; return variate_generator<base_type&, dist_type>(_rng, dist_type(0, n-1))(); } private: base_type& _rng; }; static rng_type rng; static integer_random_number_generator<rng_type, int> int_gen( rng ); static integer_random_number_generator<rng_type, long> long_gen( rng ); static real_random_number_generator<rng_type, float> float_gen( rng ); static real_random_number_generator<rng_type, double> double_gen( rng ); int random_num( int max ); int random_num( int min, int max ); long random_num( long max ); long random_num( long min, long max ); float random_num( float max ); float random_num( float min, float max ); double random_num( double max ); double random_num( double min, double max ); #endif /* RANDOM_H */ #include "random.h" #include <iostream> using namespace std; int main( int argc, char ** argv ) { unsigned int seed; int num; int max; int i; cin >> ws >> seed; cin >> ws >> num; cin >> ws >> max; cout << "seed : " << seed << endl; cout << "num : " << num << endl; cout << "max : " << max << endl; rng.seed( seed ); cout << "seeded rng..." << endl; cout << num << " raw numbers from rng" << endl; for( i = 0; i < num; i++ ) { cout << rng() << endl; } cout << num << " random integers using rng" << endl; for( i = 0; i < num; i++ ) { cout << random_num( max ) << endl; } return 0; }

2 2

Failures in Solaris/gcc build
by Fernando Mato Mira 21 Oct '05

21 Oct '05

Hello, I built Boost on Solaris 9 with gcc 3.3.3 but I saw many "...failed" messages while building. Also, in the destination lib directory there's no regex library, and I think there should be one. There are only the libraries for: libboost_filesystem libboost_iostreams libboost_prg_exec_monitor libboost_python libboost_signals Thanks

1 0

Boost Test Memory Dumping...
by Matt Amato 20 Oct '05

20 Oct '05

I have a simple Boost program using the unit test framework. When I run the program in debug, I get a dump of memory leaks. I can't find a way to stop these memory leaks from being reported (other than fixing the leaks of course). What is the proper way of disabling this output? I tried using boost::unit_test::unit_test_log.set_threshold_level but that didn't seem to work. Any ideas? Thanks, Matt Running 4 test cases... *** No errors detected Detected memory leaks! Dumping objects -> {185} normal block at 0x00C3ABF0, 32 bytes long. Data: <Oct 19 2005 19:1> 4F 63 74 20 31 39 20 32 30 30 35 20 31 39 3A 31 {182} normal block at 0x00C3AAF0, 32 bytes long. Data: <Oct 19 2005 19:1> 4F 63 74 20 31 39 20 32 30 30 35 20 31 39 3A 31 {176} normal block at 0x00C3A3E0, 976 bytes long. Data: <<!DOCTYPE VAR [<> 3C 21 44 4F 43 54 59 50 45 20 56 41 52 20 5B 3C Object dump complete. Press any key to continue

2 1

[Boost on Pocket PC] Is Boost supported on Pocket PC platforms?
by Ansuman Kar 20 Oct '05

20 Oct '05

Hi, I'm a newbie user of Boost libraries. We have a requirement for making our sources work on Win32 and Pocket PC platforms. From my early look inside the boost libraries I can see the serious advantages of using them; but would like to find out which Boost libraries are supported on Pocket PC before using them. Quick searches through google and on boost.org site did not provide authoritative results, so I'm posting this question here - please let me know if a different alias is better suited for this question. Thanks. -Ansu __________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com

3 2

[Boost.Graph] Double sided edge properties in undirected graph
by Ferdi Smit 20 Oct '05

20 Oct '05

What is the easiest (is there any) way to associate an edge property with both edge ends in an undirected graph in the BGL? I would like to iterate over the incident edges of a vertex, and obtain the edge property for that side of the edge the vertex is on. Ie. for A (5) <--E--> (1) B when iterating the incident edges of A, a request for this edge's (E) property would return 5, and when iterating vertex B's incident edge (E) it would return 1. For a directed graph this is simple: just store a "source" property and a "target" property in each edge. However in the case of an undirected graph the source vertex of an edge will always be the one you're iterating over incident edges from. So this wouldn't work, as it always return the "source" property then, no matter if I'm at A or B. A solution that came to mind is to convert the undirected graph into a directed graph with double edges everywhere. Then I can simply iterate over the out_edges and obtain the right property. However, this seems to be tedious and possibly a waste of space as I'm reinventing undirected graphs manually. Plus I have to rewrite edge removal etc. to keep things consistent. I'm aware that this is how BGL works internally anyhow for undirected graphs, so I don't want to reinvent it. Another "solution" is to store an associated vertex with the properties for the edge, giving two (vertex, value) pairs per edge. First of all this wastes space, and secondly it proves difficult to typedef this property inside the graph type as it is a cyclic dependency. External property maps could do the trick, but the space issue is still unresolved. (I'm primarily speaking of adjacency_lists in this post) A different issue: isn't BGLs genericity an illusion? Compared to for example the illusion of container independence in the STL? So far I've always needed to know what containers are used for the graph in order to make assumptions about iterator validity. For any algorithm using removal or addition a list is basically required, with all the added problems of the vertex indices not being ints... Is BGL still being actively developed? Can I expect positive changes in this area in the future? I really like the concept (no pun) of the BGL, but it's difficult to use at the moment imho. -- Regards, Ferdi Smit (M.Sc.) Email: Ferdi.Smit(a)cwi.nl Room: C0.07 Phone: 4229 INS3 Visualization and 3D Interfaces CWI Amsterdam, The Netherlands

1 0

MSVC and PDB files.
by Jonathon Bell 20 Oct '05

20 Oct '05

How do I use BOOST JAM to build and deploy PDB files for both the debug and release configurations of the various BOOST libraries? I'm using the Visual C++ 7.1 Toolset... _________________________________________ //* Jonathon Bell jbell(a)mathsoft.com //* Mathsoft Engineering & Education, Inc //* 101 Main Street, Cambridge, MA, 02142

3 2

Tokenizer: Low value as seperator
by CN 20 Oct '05

20 Oct '05

Hi! Library version 1.33.0. The input string contains null characters. I want to use null character as the seperator. The following code produces only "X". Why "Y" and "Z" are discarded and how to fix this code? ========= #include<iostream> #include<boost/tokenizer.hpp> int main(int argc, char* argv[]) { using namespace std; using namespace boost; string str="X\0Y\0Z"; typedef tokenizer<boost::char_separator<char> > Tok; char_separator<char> sep("\0"); Tok tokens(str, sep); for(Tok::iterator tok_iter = tokens.begin();tok_iter != tokens.end(); ++tok_iter) cout << *tok_iter; return EXIT_SUCCESS; } ========= Thank you in advance! CN -- http://www.fastmail.fm - Access your email from home and the web

4 6

There is a error in the file licence_info.cpp under tools\bcp
by Huifeng Shen 20 Oct '05

20 Oct '05

The original line 18 is (pay attention the correspond the parentheses) "Copyright|\\(c\\)|? I compile bcp with vc71 toolset and fails. I change this line with "Copyright|\\(c\\)|?" It's OK. I also check the code in the CVS, This error is not corrected.

3 4

Regression tests
by John Grabner 20 Oct '05

20 Oct '05

Hi Guys, I remember seeing the regression test laid out in a table on the web somewhere. You could navigate to whichever result you were interested in. can someone point my in the right direction? John.

2 1

Re: [Boost-users] [MultiIndex] Key extraction from a base member
by JOAQUIN LOPEZ MU?Z 20 Oct '05

20 Oct '05

Hello Bruno, thanks for using Boost.MultiIndex! ----- Mensaje original ----- De: Bruno Martínez <br1(a)internet.com.uy> Fecha: Miércoles, Octubre 19, 2005 10:46 pm Asunto: [Boost-users] [MultiIndex] Key extraction from a base member > Hi. > > I have the following problem with MultiIndex. For > > struct Base { > int id; > }; > > struct Der : Base { > }; > > I can't make a key extractor. > [explanation on why it doesnt work snipped] > Maybe the solution is to put some enable_ifs in member. > Basically, something like that should be done, right. Actually enable_if only works for highly compliant compilers, so I'll have to resort to some uglier mechanism, but it can be done. This is planned to be solved (or added as a new feature, if you wish) in Boost 1.34. The problem was first brought to my attention in http://tinyurl.com/dnfzs. In the meantime I'm afraid you are forced to write your own key extractor (which is trivial, in any case.) Best regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

2 1