Re: [boost] Re: ublas & custom containers?

From: Kresimir Fresl (fresl_at_[hidden])
Date: 2002-03-14 09:29:41

jhrwalter wrote:

[...]
 > (but I'm unsure, if valarray<> is a legal array_type of
 > numerics::vector currently ;-).

It is ... with few minor modifications (at least with g++ 3.0.4).

std::valarray<> does not have `iterator' & `const_iterator'
types. Therefore `iterator_type' & `const_iterator_type'
in numerics::vector<> can't be defined. But they are not
needed if `indexed_iterator<>' is used instead of nested
iterator classes.

So, I first added

#ifndef NUMERICS_USE_INDEXED_ITERATOR
         typedef typename A::const_iterator const_iterator_type;
         typedef typename A::iterator iterator_type;
#endif

in numerics::vector<>.

But to compile some simple examples with macro
NUMERICS_USE_INDEXED_ITERATOR defined,
I had to add few typename's in `vector_pr.h':

line 184:
    NUMERICS_TYPENAME vector_type::iterator::iterator_category> iterator;
instead of:
    vector_type::iterator::iterator_category> iterator;

line 186:
    NUMERICS_TYPENAME vector_type::const_iterator::iterator_category> 
const_iterator;

line 664:
    NUMERICS_TYPENAME vector_type::iterator::iterator_category> iterator;

and line 666:
    NUMERICS_TYPENAME vector_type::const_iterator::iterator_category> 
const_iterator;

Now this works:

   #include <valarray>
   #include <boost/numerics/ublas/vector.h>

   typedef numerics::vector<double, std::valarray<double> > vector;
   vector v1(10), v2(10), v3(10);
   v3 = v1 + v2;

BTW, did you measure what is more efficient: indexed_iterator<>
or iterator classes nested in numerics::vector<>?

Sincerely,

fres