Re: [Boost-users] Traversing through a multi_array and accessing the data set...

From: Graham Reitz (graham.cpp_at_[hidden])
Date: 2007-09-04 13:50:03

Ahh...thanks much!

On 9/4/07, François Duranleau <duranlef_at_[hidden]> wrote:
> On Tue, 4 Sep 2007, Graham Reitz wrote:
>
> > How do you access the data in the example below?
> >
> > Thanks much,
> >
> > Graham
> >
> > boost::multi_array<double,2> multi_test;
> > boost::multi_array<double,2>::iterator multi_test_iter;
> > boost::multi_array<double,2>::extent_gen extents;
> >
> > multi_test.resize(extents[2][3]);
> >
> > for (multi_test_iter = multi_test.begin();
> >       multi_test_iter != multi_test.end(); ++multi_test_iter)
> > {
> > // How do you get(set) at the current data set pointed to by multi_test_iter?
> > }
>
> multi_test_iter in this example is an iterator on rows. You need to add an
> extra loop to iterate on those elements, something like
>
> for ( multi_test_iter = multi_test.begin() ;
>        multi_test_iter != multi_test.end() ;
>        ++ multi_test_iter )
> {
>      for ( boost::multi_array< double , 2 >::value_type::iterator
>              inner_multi_test_iter = multi_test_iter->begin() ,
>              end_inner = multi_test_iter->end() ;
>            inner_multi_test_iter != end_inner ;
>            ++ inner_multi_test_iter )
>      {
>          // here, *inner_mult_test_iter returns a reference to a double
>      }
> }
>
> --
> François Duranleau
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