Submatrices in MTL

Please note that I'm not subscribed to the list list and so a CC would
be appreciated.

We're attempting to develop a neural network class on top of the MTL
framework and have ran into two problems.

First, is it possible to easily 'cut+paste' sections from and to
matrices.  For example:

A = [ 0 1 2 3 ] B = [10 11 12 13]
    [ 4 5 6 7 ]     [14 15 16 17]

Can we easily take [1 2] from A and paste it over part of B such that:
                   [5 6] 


B = [10 1 2 13]
    [14 5 6 17]

We've tried using sub_matrix to pull it out but can't get it to work: 

#include <iostream>
#include "mtl/mtl.h"

using namespace mtl;

typedef matrix< double,
                rectangle<>,
               array< dense<> >,
               row_major>::type mlp2d;

int main()
{
    mlp2d a(6,6);
    mlp2d b(2,2);
    double counter=0;
    int i,j;

    for(i=0;i<6;i++)
    {
        for(j=0;j<6;j++)
        {
            a(i,j)=counter;
            counter++;
        }
    }

    b=a.sub_matrix(0,2,0,2);

    print_all_matrix(a);

	print_all_matrix(b);

    return 0;
}


Second, what is the most efficient way to implement simple 3d matrix
operations -- basically we want to be able to cut and paste submatrices
as above but in 3d (although there is the possiblity of just doing it as
a set of 2d matrices if there is no alternative).

Thanks for any help you can offer.

Mark Hymers,
Sensory Systems Research Group, Newcastle University 

-- 
Mark Hymers, University of Newcastle Medical School
Intercalating Medical Student (BMedSci)
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