[ublas] help using subrange(matrix<>, ...)

From: Manoj Rajagopalan (rmanoj_at_[hidden])
Date: 2006-11-18 19:39:27

Hi

   I have a function with the prototype:

    template<typename E>   void initialize(matrix_expression<E>& A);

When i call this function with:

     matrix<int> A(5, 5);
     initialize(subrange(A, 1, 3, 1, 3));

I get a compiler error (g++ 4.1.0, Fedora Core 5, P4 (i686))

   error: invalid initialization of non-const reference of type 
‘matrix_expression<matrix_range<matrix<...> > >&’ from a temporary of 
type ‘matrix_range<matrix<...> >’

error: in passing argument 1 of ‘void initialize(matrix_expression<E>&) 
[with E = matrix_range<matrix<...> >]’

     Have I made a mistake in my C++? I know matrix_range<> inherits 
matrix_expression<matrix_range<>> (CRTP). subrange() generates a 
matrix_range<> temporary but why can't I access it using a non-const 
reference. I have every intention of modifying the submatrix :-)

Thanks
Manoj Rajagopalan