Re: UBLAS: advice on argument types please

From: speedsnaii speedsnaii_at_[hidden])
Date: 2003-02-26 04:56:46

I think I found out now, what I was missing. I am working with 
expressions now, and so I have to refer to the arguments as

arg().size()

But this still leaves me with even more questions:

Why would I prefer:

template<class E>
void foo(const vector_expression<E>& arg) 
{
    arg().size();
}

over

template<class V>
void foo(const V& arg) 
{
    arg.size();
}

?

When rethinking my problem it seems to me as if I would need to 
decide whether my algorithm should work on expressions or on 
containers. But where is my container? vector is a container and an 
expression. This confuses me somewhat.
Ok, my original question was of how to
foo(m.column(0)) or foo(m.row(1))
and this automatically made an expression from my rows/cols.
So creating my subroutine in a way is implementing an algorithm. But 
as I feel this is different from what uBLAS does in functional.hpp, 
isn't it? 

What I originally was looking for was a container concept similar to 
std::vector that extends to matrix. I am aware that uBLAS is much 
more powerful, but leaves me with the question of how to write my own 
subroutines. Could you Joerg or anyone else give me some ideas of how 
to do this (conceptually simple) task or point me to some example 
code?

Thank you for your help,
Roland