Re: UBLAS: advice on argument types please

From: speedsnaii speedsnaii_at_[hidden])
Date: 2003-02-26 11:01:14

This is an addendum to my previous post...

I looked into the bayesclasses as you were suggesting and as far as I 
see the use of the uBLAS does something I was presuming before. There 
is a local Vec and Matrix class which are defined as following:

==============================================================
class Vec: public ublas::vector<double>
{
...
    template <class E>
     Vec(const ublas::vector_expression<E>& e) : ublas::vector<double>
(e)
         {}  // vector_expression conversion constructor
...
  template <class E>
    Vec& operator=(const ublas::vector_expression<E>& r)
     {   // Expression assignment, may be dependant on r
         ublas::vector<double>::operator=(r);
         return *this;
     }     
...
}
==============================================================

This essentially removes the expression information in the 
assignment. Am I right? Now when defining
void foo(Vec& arg) {}
there is no passing of the expression tree to the function, since it 
is converted to vector<double> when passed as an argument.
I presume this will create a temporary, won't it?

So I end up wondering whether it is a good idea to use 
boost::multi_arry as a container and boost:numeric::matrix for 
expression evaluation? Will it be easy to interface back and forth? 
Or is this a completely odd idea?

Listening eagerly,
Roland