Re: [ublas] Ascertaining the numberof elements in a mapped_matrix?

From: Michael Stevens (mail_at_[hidden])
Date: 2005-11-06 13:46:15

On Thursday, 3. November 2005 16:31, Angus Leeming wrote:
> It appears that mapped_matrix has no non_zeros() member function, yet
> the constructors of other matrix types (say, compressed_matrix) have
> a field for this information.

The 'nnz' and function replaces 'non_zeros'.

> What is the recommended way, therefore to create a compressed_matrix
> from a mapped_matrix?

I would simply use the general expression constructor with an non_zeros 
parameter.
 compressed_matrix c (m, m.nnz() );

The efficiency will non be as great as a specialised constructor but should be 
OK.

Michael
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