September 2002 - Boost-users

lambda library bug --- endl?
by Ken Yarnall 13 Sep '02

13 Sep '02

Hi there. I have a recent CVS version of Boost installed, and am using g++ v3.2. I tried to compile the following program: -----------lambda_test.cpp------------ #include <iostream> #include <string> #include <list> #include <algorithm> #include <boost/lambda/lambda.hpp> using namespace std; using namespace boost::lambda; int main() { list<int> ell; for (int i=0; i<100; ++i) ell.push_back(4*i-1); for_each(ell.begin(), ell.end(), cout << _1 << endl); } -------------------------------------- I am met by: % g++ -I/usr/local/boost -c lambda_test.cpp lambda_test.cpp: In function `int main()': lambda_test.cpp:17: no match for `const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda:: bitwise_action<boost::lambda::leftshift_action>, boost::tuples::tuple<std::ostream&, boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > > << <unknown type>' operator Any suggestions? I am aware that I can replace endl by '\n' and get a compilable program. I worry that this problem extends to other manipulators... Thanks, Ken

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Regex performace for NLP
by shevaxp 13 Sep '02

13 Sep '02

I´m actually developping a NLP appication (a morphological analyzer) I´ve implemented the tokenizer using boost regex++ engine, but the performance is poor in comparition with Perl´s one for the same task. I´ve read some messages about this questions in the mailing list, and then realized that boost regex++ gives really more than what i needed, and the price I have to pay is a lack of speed. But I wouldn´t like to mistake twice, so I´ve decided to make to all of you the question: Is there something I could change to enfinciently use boost regex in NLP programming? If not, what´s the better(at least better than Perl!) regex engine in C/C++ for NLP programming (and,of course... OPEN SOURCE) ? Thank you. (and sorry for my english) Bye!

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Newbie: uBLAS slow?
by Thomas Willhalm 12 Sep '02

12 Sep '02

Hello, I'm new to ublas, so it's easily possible that I overlooked something obvious. The first thing I tried to calculate was the following line: numerics::matrix<double> M(dimension,n); numerics::matrix<double> Covariance = numerics::prod(M,numerics::trans(M))/n; where dimension is 50 and n is 8000. Unfortunately. it turned out that the following "stupid" code actually performs better: numerics::matrix<double> Covariance(dimension,dimension); for (int i=0; i<dimension; ++i) for (int j=0; j<dimension; ++j) { Covariance(i,j)=0; for (int k=0; k<n; ++k) Covariance(i,j) += M(i,k)*M(j,k); Covariance(i,j) /= n; } What am I doing wrong? I'm using gcc 2.95.3 under Linux 2.4.18 on a mobile Pentium III, if it matters. Thanks in advance Thomas

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Newbie boost::bind problem
by Mark Snelling 12 Sep '02

12 Sep '02

Hello, I need some help using the boost::bind library. I have a map of objects with a string as the key eg map<string, Block*>, what I want to do is call a member function on each Block* in the map using the std::for_each algorithm. The trivial solution would be to craft my own loop and iterate through the list calling the member function on each one. But I'm sure that the boost::bind library can help me out there. class Block { public: void update(int x); }; void main() { map<string, Block*> blocks; for_each(blocks.begin(), blocks.end(), *****); } what should I replace the ***** with to call update() on each block? Any help appreciated! Mark.

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boost::shared_ptr confusion...
by someuserat 12 Sep '02

12 Sep '02

I've just started working on my first project trying to fully utilize STL and the boost libraries, and have already run into something that I can't seem to figure out... I'm trying to use find_if to check if a member function of an object contained in an array returns true. It will only return true for a single object in the collection, so I just need the first instance. When the vector is declared like this: vector<Widget*> col; This statement compiles... vector<Widget*>::const_iterator i = find_if(col.begin(),col.end(),mem_fun(&Widget::IsPrimary)); However, when I try to use the boost::shared_ptr library like so... typedef boost::shared_ptr<Widget> WidgetPtr; vector<WidgetPtr> col; This statement causes gcc to bark with all manner of errors... vector<WidgetPtr>::const_iterator i = find_if(col.begin(),col.end(),mem_fun(&Widget::IsPrimary)); I'm thinking I've missed something basic, but it's eluding me...

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boost.function with CW 8.2 on W2k
by Bertolt Mildner 12 Sep '02

12 Sep '02

I get the following warnings when I use boost::function with CW 8.2 on W2k: Warning : variable / argument 'deprecated' is not used in function (included from: function10.hpp:28 function.hpp:37 Test.cpp:8) function_template.hpp line 388 BOOST_FUNCTION_DEPRECATED_INNER Warning : variable / argument 'deprecated' is not used in function function.hpp line 874 BOOST_FUNCTION_DEPRECATED_INNER Warning : variable / argument 'deprecated' is not used in function function.hpp line 867 BOOST_FUNCTION_DEPRECATED_INNER I'm using a relatively new CVS snapshot (<2 days old). -- Free Crypto Token - FCT www.FreeCryptoToken.org

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bjam on hpux
by Glen Knowles 11 Sep '02

11 Sep '02

I'm trying to build boost on hp/ux 11.11 with the aCC 3.35 compiler but can't seem to get a working jam. My tools tell me that the bjam.gz binary for hp/ux is not a valid gzip file and my attempts to compile jam result in a large number of errors which I can get into if needed. Could someone verify that the hp/ux bjam.gz is good? Any help is appreciated, Glen

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Re: bjam on hpux
by Glen Knowles 11 Sep '02

11 Sep '02

"Toon Knapen" <toon.knapen(a)si-lab.org> wrote: > > I'm trying to build boost on hp/ux 11.11 with the aCC 3.35 compiler but > > can't seem to get a working jam. My tools tell me that the bjam.gz binary > > for hp/ux is not a valid gzip file and my attempts to compile jam result in > > a large number of errors which I can get into if needed. Could someone > > verify that the hp/ux bjam.gz is good? > > I've build the prebuilt on HP-UX 10.2 but I guess they are binary compatible. > If you have trouble compiling bjam yourself, could you provide the error-log ? > Finally I just renamed bjam.gz to bjam and it seems to run. My problem was that the bjam.gz wasn't a .gz after all. We'll see how much futher I get. Thanks, Glen [Non-text portions of this message have been removed]

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BOOST_MSVC6_MEMBER_TEMPLATES
by jacob_bondski 10 Sep '02

10 Sep '02

Hi, The VC++ compiler (6.0 with SP 5) has problems with member function templates. We have encountered a couple of situations where a shared_ptr was created and an attempt was later made to assign a raw pointer to it. However, 1) The compiler fails to recognise that you can't assign a raw pointer to an existing shared pointer object 2) The compiler fails to generate any code whatsoever for the assignment 3) The compiler remains silent about its problems We realise that one way to help the compiler to recognise invalid statements is to undefine BOOST_MSVC6_MEMBER_TEMPLATES. We are now considering to enforce this undefine across our project. Does anyone know which boost features would become inaccessible? Regards, Jacob

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function docs
by Ihsan Ali Al Darhi 10 Sep '02

10 Sep '02

Hi... I downloaded Boost 1.28.0. I looked at the function library folder but I didn't see any documentation on how to use this library. Where's it? If there isn't, who would volunteer and explain how to use this library? I am using gcc 3.2 on Win2000 and sometimes on Win98. Mo

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