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

program options validate function question
by Suresh T 07 Jun '06

07 Jun '06

hello boosters, I have a class ( say user_type ) that i would like to use for storing cmd line option and therefore i have a validate function for the same void validate ( boost::any& v, const std::vector<std::string>& xs, <user_type> * target, int i ) I wanted to know if it is possible to access the actual variable in which the option would be stored from within the validate function. Meaning if i the options_description is something like below: //here user_type_object is an instance of user_type ("option_name" , po::value<user_type>(&user_type_object), "some option" ) Is it possible to access the user_type_object in the validate function? If so please let me know how ? P.S: I am resending this mail as my mail sys. crashed after i sent it the first time in morningso not sure if this was sent. If any one has replied earlier request that they redo as i have lost earlier mails Thanks & Rgds, --------------------------------------------------------------------------------------------------------- Suresh.T

1 0

program options validate function question
by Suresh T 07 Jun '06

07 Jun '06

hello boosters, I have a class ( say user_type ) that i would like to use for storing cmd line option and therefore i have a validate function for the same void validate ( boost::any& v, const std::vector<std::string>& xs, <user_type> * target, int i ) I wanted to know if it is possible to access the actual variable in which the option would be stored from within the validate function. Meaning if i the options_description is something like below: //here user_type_object is an instance of user_type ("option_name" , po::value<user_type>(&user_type_object), "some option" ) Is it possible to access the user_type_object in the validate function? If so please let me know how ? Thanks & Rgds, --------------------------------------------------------------------------------------------------------- Suresh.T

1 0

[serialization] binary_iarchive performance degradation with Intel 9.0 compiler
by Bill Lear 06 Jun '06

06 Jun '06

It could be that I'm being foolish, or that there is something very strange going on in how the Boost serialization library interacts with the Intel C++ compiler that I don't understand. I'll post a short question first, eliding underlying motivations, to see if this warrants further discussion. I am running on 64-bit Linux, using the Intel C++ compiler, version 9.0, and gcc 3.4.5. I have a large, complex data structure that I am serializing. All serialize methods use the BOOST_SERIALIZATION_NVP macro. The data structure serializes and deserializes accurately for each of text, xml, and binary archives. The size on disk is about 250 megabytes, using the binary archives. The load method I use is roughly this: #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> //#include <boost/archive/text_oarchive.hpp> //#include <boost/archive/text_iarchive.hpp> //#include <boost/archive/xml_oarchive.hpp> //#include <boost/archive/xml_iarchive.hpp> #include "Foo.hh" Foo* load(const string& filename) { istream ifs(filename.c_str(), ios::binary); Foo* foo = 0; boost::archive::binary_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(foo); return foo; } Above this method, note the commented-out text and xml archive headers. Here is the strange part: When using the Intel compiler, and run with the text and xml archive headers commented out, the load method takes about 9.6 seconds. When I uncomment the text and xml headers, the load time almost doubles, to 18.8 seconds or so. I do not see this with gcc. So the question is: have I done something foolish here, or is this wacky? I am using the following command to compile the code: % icpc -O2 -Ob2 -ip <...> Any help appreciated. Bill

4 7

Re: [Boost-users] [multi_index].[composite_key] Index creation atrun-time.
by JOAQUIN LOPEZ MU?Z 06 Jun '06

06 Jun '06

----- Mensaje original ----- De: Prashant Thakre <prashant.thakre(a)gmail.com> Fecha: Martes, Junio 6, 2006 9:06 pm Asunto: Re: [Boost-users] [multi_index].[composite_key] Index creation atrun-time. > Hi, > Thanks for the reply. You're welcome. I'm afraid I'll have to ask for some more info before I can try to answer your original question, though :( > This is what I am trying to achieve: > a) Each entry in the container will have tuple containing n-elements > tuple < t0, t1 ..., tn >, where n is known at run-time. This entry > will also have other elements. But, how are you planning to actually implement this? Certainly you can't do the following: class element { public: boost::tuple<t0,t1,...tn> tp; ... }; because you don't know n at compile time. This question is important, since how you actually implement the run-time knowledge of n will surely determine the way you can plug a composite_key into the scheme. If you can provide some actual code, no matter how sketchy, showing how you implement your element type, so much the better. Looking fwd to your feedback, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

1 0

Re: [Boost-users] [multi_index].[composite_key] Index creation at run-time.
by Prashant Thakre 06 Jun '06

06 Jun '06

Hi, Thanks for the reply. This is what I am trying to achieve: a) Each entry in the container will have tuple containing n-elements tuple < t0, t1 ..., tn >, where n is known at run-time. This entry will also have other elements. b) Multi_index container will have a composite_key, consisting of each tuple element. As per 2) it should be possible to just have std::vector<T> as a tuple and define the composite key in terms of each element of the tuple i.e. [ tuple.at(0), ..., tuple.at(n-1) ]. Please correct me if am wrong. Thanks once again. -- regards, Prashant Thakre > Date: Tue, 06 Jun 2006 13:00:09 +0200 > From: Joaqu?n M? L?pez Mu?oz <joaquin(a)tid.es> > Subject: Re: [Boost-users] [multi_index].[composite_key] Index > creation at run-time. > To: boost-users(a)lists.boost.org > Message-ID: <44856039.19A00631(a)tid.es> > Content-Type: text/plain; charset=iso-8859-1 > > Prashant Thakre ha escrito: > > > Hi, > > I would like to know if it's possible to define a multi_index using > > composite_key,where the number of keys which are part of the > > composite_key are only known at run-time. > > Thanks again. > > -- > > regards, > > Prashant Thakre > > Hello, > > The short answer is no, you must know the number of keys a > composite_key is made of at compile time. The long answer is, > depending on your usage scenario, maybe you can have something > close to what you're after: > > 1. If the maxium number of keys of the composite_key is bounded > then you can use that maximum and later on, at run-time, take > advantage of only the first N key slots. > 2. You can have std::vector<> as the key, the comparison semantics > of this container in some ways resembles that of an infinite-length > composite key. > > If you can describe what you are pursuing with a little more detail > maybe I can provide more focused help. > > Thanks for using B.MI, best regards, > > Joaqu?n M L?pez Mu?oz > Telef?nica, Investigaci?n y Desarrollo

1 0

boost::pool
by James Swift 06 Jun '06

06 Jun '06

Hi boost users, I have a question regarding the best use of the boost pools and shared_ptr Consider the following tree node object. class A { public: typedef boost::shared_ptr< A > SPA; typedef std::vector< SPA > SPAVec; SPAVec children; }; This class allows me to have a tree or trees where some of the nodes may be shared. E.g. // tree1 tree2 // X Z // Y Y Y X // Y Y Logically the root of tree1, X has two children Y and Y but physically of course I only have one copy of Y in memory. Other trees, e.g. tree2 can also share these branches. Now assume I'm also very often constructing and destroying nodes. An object pool is an obvious optimisation to try out. However shared_ptr would need to call object_pool::destruct() instead of delete when it really wants to destroy the object. Or singleton_pool::free() but this causes more difficulties for me because I want to control the lifetime of the pool separately for each instance of my objects which are working on these trees. Can anyone offer a nice solution to this problem? kind regards, James Swift.

2 2

random library: initializaing a generator.
by dvir schirman 06 Jun '06

06 Jun '06

Hi I am using boost/random library in order to create a normal distributed noise. I want to call my my_class::noise() functions several times, but I want to initialize the generator only once. I tried to declare and initialize the generator at the constructor of my_class, but then my_class::noise() doesn't recognized the generator. I wrote it the following way: my_class::my_class() { boost::mt19937 gen(42u); } my_class::noise() { boost::normal_distribution<float> n_d(5, 10); //n_d(mean,stdev) boost::variate_generator<boost::mt19937&, boost::normal_distribution<float> > normal(gen, n_d); return normal(); } I guess I need to declare the generator at the header, and only initialize it at the constructor, but I don't know how to do it. Thanks for your help. Dvir

4 4

Re: [Boost-users] random library: initializaing a generator.
by David Klein 06 Jun '06

06 Jun '06

boost-users-bounces(a)lists.boost.org wrote: > Hi > > I am using boost/random library in order to create a normal > distributed noise. I want to call my my_class::noise() functions > several times, > but I want to initialize the generator only once. > I tried to declare and initialize the generator at the > constructor of my_class, but then my_class::noise() doesn't > recognized the generator. I wrote it the following way: > > my_class::my_class() > { > boost::mt19937 gen(42u); > > } > > my_class::noise() > > { > > boost::normal_distribution< > > float> n_d(5, 10); //n_d(mean,stdev) > > boost::variate_generator<boost::mt19937&, > boost::normal_distribution<float> > normal(gen, n_d); > > return normal(); > > } > > > > I guess I need to declare the generator at the header, and > only initialize it at the constructor, but I don't know how to do it. > > Thanks for your help. > Dvir hi dvir, this is untested, but should do what you want. class my_class { boost::mt19937 gen_; public: my_class( void ) : gen_(42u) { } void noise( void ) { boost::normal_distribution<float> n_d(5, 10); //n_d(mean,stdev) boost::variate_generator<boost::mt19937&, boost::normal_distribution<float> > normal(gen_, n_d); } }; HTH dave

1 0

[multi_index].[composite_key] Index creation at run-time.
by Prashant Thakre 06 Jun '06

06 Jun '06

Hi, I would like to know if it's possible to define a multi_index using composite_key,where the number of keys which are part of the composite_key are only known at run-time. Thanks again. -- regards, Prashant Thakre

2 1

[Test] Can Boost Test Tools Be Used in Multiple Threads?
by Wu Yinghui, Freddie 05 Jun '06

05 Jun '06

Dear all, I've been trying to write some test code that involves 2 concurrent threads of execution. But I found that there are occasional crashes in the test tool code when some BOOST_CHECK_*() are triggered. So my question is: Are Boost test tools designed to be used in multiple threads? Cheers, Freddie -- Wu Yinghui, Freddie Research & Development Software Engineer Volume Interactions Pte Ltd 1 Kim Seng Promenade, #12-01 Great World City East Tower Singapore 237994 Tel: +65 62226962 (Ext 216) Fax: +65 62226215 Email: yhwu(a)volumeinteractions.com URL: http://www.volumeinteractions.com Important: This message is intended for the recipient(s) addressed above. It contains privileged and confidential information. If you are not the intended recipient, please notify the sender immediately by replying to this message and then delete it from your system. You must not read, copy, use, or disseminate this communication in any form. Thank you.

3 3