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

Interval Library?
by David Brownell 25 Jan '04

25 Jan '04

I think I am looking for functionality that is contained with the Interval library, but am having a hard time digesting the documentation for this particular library. I would like an Interval that goes from a min_value to a max_value, where each value is the previous value + N. For example, the interval {2, 6, 10, 14, 18} has a minimum value of 2, a maximum value of 18, and increments by 4. Given this interval, I would like a function, Foo, that works as follows: Interval(2, 18, 4) i; i.Foo(2) == 2 i.Foo(6) == 2 i.Foo(0) == 2 i.Foo(18) == 18 i.Foo(20) == 18 i.Foo(5) == 6 i.Foo(3) == 6 Is this something that can be done with the Interval library, or am I missing the point? :) Thanks in advance for your help! David Brownell

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Import Error: DLL load Failed
by Shukla, Nitin (Export) 24 Jan '04

24 Jan '04

Hello, I fairly new to the Boost tool. I have just build the Boost.Python 1.30.2. To get started I used the examples "getting_started1.cpp and getting_started2.cpp." and build the required DLLs using the bjam tool. I get following error when I try to import the module "getting_started1" into python : "ImportError: DLL load failed: The specified module could not be found." Can someone help me resolve this error? I am using PythonWin 2.2.1. Nitin

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RE: [Boost-users] MultiArray questions
by Neil Mackie 23 Jan '04

23 Jan '04

I'm responding to Mark Phillips series of questions about MultiArray. I began using MultiArray last year and quickly realised I was unclear how to use the library. Posting to this list did not help and I resorted to emailing the developer. He had not responded, as he is not subscribed to this list. However he was helpful in answering my questions. My advice is to follow the same procedure as I did, contact details are available at http://www.boost.org/libs/multi_array/doc/index.html although the email address I used was garcia at cs dot indiana .edu. Please post your replies back to the list as I too wonder about the efficiency of MultiArray. It is nice to see a well formed set of questions and I look forward to seeing an equally clear set of answers. Regards, Neil (J Mackie). *********************************************************************************** Ofcom is the regulator for the UK communications industry, with responsibilities across television, radio, telecommunications and wireless communications services. Ofcom exists to further the interests of citizen-consumers as the communications industries enter the digital age. Ofcom has taken over the responsibilities and assumed the powers of the five former regulators it has replaced - the Broadcasting Standards Commission, the Independent Television Commission, Oftel, the Radio Authority and the Radiocommunications Agency. This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the originator of the message. This footer also confirms that this email message has been scanned for the presence of computer viruses. Any views expressed in this message are those of the individual sender, except where the sender specifies and with authority, states them to be the views of Ofcom. ***********************************************************************************

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jweb
by Emre Turkay 21 Jan '04

21 Jan '04

Hi All, I was trying to compile the boost-graph library documentation (pdf) and I've done the following, and got the error shown. -bash-2.05b$ pwd /home/emre/boost/boost-1.30.2/libs/graph/doc -bash-2.05b$ make jweb -np isomorphism-impl-v3.w make: jweb: Command not found make: *** [isomorphism-impl-v3.tex] Error 127 -bash-2.05b$ Can someone tell me what this "jweb" is ? Thanks, emre

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RE: [Boost-users] tuple problems 2
by Ben Hutchings 19 Jan '04

19 Jan '04

Programmer_blabla <Programmer_blabla(a)hotmail.com> wrote: > Ok thank you, I will post this on microsoft.public.vc.language. > > About the other thing, I originally thinked about that. But what to > specifiy, using the typedef's won't work either (see below): > > int i; > boost::tuple<int> data(27); > > i = boost::tuples::get<0, boost::tuple<int>::head_type, > boost::tuple<int>::tail_type>(data); //ok > i = boost::bind(&boost::tuples::get<0, boost::tuple<int>::head_type, > boost::tuple<int>::tail_type>, _1)(data); //error <snip> Yes, I see, there's ambiguity as to whether this means template<int N, class HT, class TT> typename access_traits<typename element<N, cons<HT, TT> >::type> ::non_const_type get(cons<HT, TT> & c); or template<int N, class HT, class TT> typename access_traits<typename element<N, cons<HT, TT> >::type> ::const_type get(const cons<HT, TT> & c); You can resolve the ambiguity by writing: typedef const int & const_int_getter( const boost::tuple<int>::inherited &); i = boost::bind(static_cast<const_int_getter *>(&boost::get<0>), _1) (data);

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Converting from const to non-const with iterator_adaptor
by Keith MacDonald 19 Jan '04

19 Jan '04

Hi, I'm stuck trying to use iterator_adaptor from the CVS head. I simply want to derive a non-const iterator from a const one derived from iterator_facade, as shown in the code below. When I compile it with VC7.1, the line marked "/* *ERROR* */" generates one of those impenetratable error messages that starts with: cannot convert from 'const Node' to 'boost::iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Differen ce>::reference' If I delete that line, so the default is used, dereferencing a non-const iterator returns a const Node. This seems such a simple requirement that there must be an easy way to do it. What am I doing wrong? Thanks, Keith MacDonald /* ========================= Code Begins ========================= */ #include <boost/iterator/iterator_facade.hpp> #include <boost/iterator/iterator_adaptor.hpp> class Node { // ... // Iteration: public: class iterator; class const_iterator; // Read-only, bidirectional iterator: typedef boost::iterator_facade< const_iterator, const Node, std::bidirectional_iterator_tag > boost_const_iterator; class const_iterator : public boost_const_iterator { public: const_iterator() {} const_iterator(const iterator& it) : m_pNode(it.base().m_pNode) {} explicit const_iterator(const Node* pNode) : m_pNode(pNode) {} friend class iterator; friend class boost::iterator_core_access; private: // Interface required by iterator_facade: reference dereference() const { return *m_pNode; } void increment() { m_pNode = m_pNode->next(); } void decrement() { m_pNode = m_pNode->prev(); } bool equal(const_iterator it) const { return m_pNode == it.m_pNode; } protected: const Node* m_pNode; }; // Read-write, bidirectional iterator, // adapted from const_iterator: typedef boost::iterator_adaptor< iterator, const_iterator, Node /* *ERROR* */ > iterator_base; class iterator : public iterator_base { public: iterator() {} explicit iterator(Node* pNode) : iterator_base(const_iterator(pNode)) {} }; const_iterator begin() const { return const_iterator(m_pChild); } const_iterator end() const { return const_iterator(NULL); } iterator begin() { return iterator(m_pChild); } iterator end() { return iterator(NULL); } private: Node* m_pChild; Node* m_pPrev; Node* m_pNext; }; /* ========================= Code Ends ========================= */

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re: BGL: BOOST_DEF_PROPERTY, BOOST_INSTALL_PROPERTY
by Vikram Anantha 18 Jan '04

18 Jan '04

<Rant> Is there really a need for using Macros (really evil macros with ## at that too) in a C++ library that espouses type safe generic programming. I wasted a couple of hours searching for the definition of vertex_name_t and edge_name_t. C'mon guys. No more gotchas. OK?? Friends dont let friends use ## macros. </Rant> Vik

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RE: [Boost-users] tuple problems
by Ben Hutchings 17 Jan '04

17 Jan '04

programmer blabla <programmer_blabla(a)hotmail.com> wrote: > Dear Booster's Booster's what? > I have a problem compiling a tuple containing an enum in a > namespace. For example: > > namespace TestTuple > { > enum ETestTuple > { > eTestTuple0 = 0, > eTestTuple1 = 1 > }; > } > > void Testtuple5() > { > typedef boost::tuple<TestTuple::ETestTuple> Tuple; > Tuple tpl; > } > > does not compile. I am using MSVC 2003.net (7.1 version), > just native code. Is this a M$ problem or is tuple broken? Looks like a compiler bug to me. > Also I get problem with > the combination > of boost::bind and tuple, for example: > > int i; > boost::tuple<int> data; > > i = data.get<0>(); //ok > i = boost::tuples::get<0>(data); //ok > i = boost::bind(&boost::tuples::get<0>, _1)(data); //error > > Has anyone a clue? boost::tuples::get has three template parameters - index, head type and tail type. Usually the type arguments can be deduced, but since you're passing the address to another template function you need to specify all three arguments. > Btw searching lists.boost.org is very hard, because google > is out of sync with the list. Try <http://news.gmane.org/index.php?prefix=gmane.comp.lib.boost> instead.

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[BGL] Custom edge-removing visitor.
by Kili2x＠netscape.net 17 Jan '04

17 Jan '04

Hello, all. I'm working on an algorithm that takes a graph and two path iterators (begin and past-the-end) as input, and removes "cross edges" (is that the right term in this case?) from the graph until the path described by the iterators is the only simple path between those two vertices. The implementation I have so far consists of a function template and three visitor class templates built on top of the boost::depth_first_visit function template. I'm still improving on it (too many out-edges from the path itself are being removed), but for now the function works as it should. Now, the graph reference passed to the operator() member function in the boost::base_visitor class template (from which I inherited) must be a constant reference, so I can't pass it to the boost::remove_edge function. Furthermore, looking at the source code included in <boost/graph/depth_first_search.hpp> (both 1.30.2 and CVS versions), the edge passed to vis.forward_or_cross_edge cannot be removed without invalidating the out_edge_iterator used in the depth-first traversal. I've worked around the first issue by keeping a non-constant reference to the graph as a member of my custom visitor class and passing that reference to boost::remove_edge, and I'm using the boost::on_finish_vertex event filter instead of boost::on_forward_or_cross_edge (adjusting the code as appropritate) in order to overcome the second issue. The workarounds look rather kludgey in code, so removing the const modifier and/or adding an extra iterator to store the current edge while incrementing the traversing iterator might enable me to come up with a more elegant solution. Would such changes to <boost/graph/depth_first_search.hpp> break compatibility with older code? Or are there other particular issues in play? BTW, Is this the appropriate list for seeking such help? TIA! Cromwell Enage __________________________________________________________________ New! Unlimited Netscape Internet Service. Only $9.95 a month -- Sign up today at http://isp.netscape.com/register Act now to get a personalized email address! Netscape. Just the Net You Need.

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question about mpl::list
by Istvan Buki 16 Jan '04

16 Jan '04

Hi all, I'm using the mpl::list template in one of my aplications but I just hit what seems to be a limit. list compile fine with 10 parameters but not with 11. I saw in the documentation that there are several header files like : #include "boost/mpl/list/list50.hpp" Are they meant to be used in cases like mine and if it is the case could someone point me to a short example ? Thanks for your help, Istvan

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