Re: [ublas] Products for "matrix inside matrix" with another matrix/vector

From: Preben Hagh Strunge Holm (preben_at_[hidden])
Date: 2007-03-05 12:09:24

> In this case you should definitely use a sparse matrix. Inserting elements is 
> simple. You can either use
> 1) a(i,j) = value; // may be slow if the matrix has already many nonzeros
> 2) a.insert_element(i,j,value); // is equivalent to 1)
> 3) a.push_back(i,j,value); // is O(1) but requires a specific ordering
> 

I have looked at the documentation... But no place states how to use 
this class.

Should I zero all elements of the matrix or would this violate the 
structure and idea of the matrix!

Or should I just fill in the elements I use (those that are not zero)?

Thanks for sharing information!