Re: [Boost-bugs] [Boost C++ Libraries] #2887: boost::mersenne_twister copy constructor

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #2887: boost::mersenne_twister copy constructor
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-03-26 15:34:56

#2887: boost::mersenne_twister copy constructor
-------------------------------+--------------------------------------------
  Reporter:  corlay_at_[hidden]  |       Owner:  no-maintainer
      Type:  Bugs              |      Status:  new          
 Milestone:  Boost 1.39.0      |   Component:  random       
   Version:  Boost 1.38.0      |    Severity:  Problem      
Resolution:                    |    Keywords:  boost::random
-------------------------------+--------------------------------------------

Comment(by corlay_at_[hidden]):

 In mersenne_twister.hpp, replacing
 {{{
 template<class Generator>
   explicit mersenne_twister(Generator & gen) { seed(gen); }
 }}}
 by
 {{{
   template<class Generator>
         explicit mersenne_twister(Generator & gen, typename disable_if<
 is_same<Generator,mersenne_twister>,int >::type = 0) { seed(gen); }
 }}}
 and add includes
 {{{
 #include <boost/utility/enable_if.hpp>
 #include  <boost/type_traits/is_same.hpp>
 }}}
 seems to solve it.
 No need to handle with the const case.

 ''Then, one has to do it for other generators'' and, in
 pass_through_engine.hpp, one can then replace
 {{{
   explicit pass_through_engine(UniformRandomNumberGenerator rng)
     // make argument an rvalue to avoid matching Generator& constructor
     : _rng(static_cast<typename helper_type::rvalue_type>(rng))
   { }
 }}}

 by
 {{{
   explicit pass_through_engine(UniformRandomNumberGenerator rng) :
 _rng(rng)
   { }
 }}}
 .

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2887#comment:1>
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