[ublas] Question regarding sparse vector's nnz() method

Subject: [ublas] Question regarding sparse vector's nnz() method
From: Rui Maciel (rui.maciel_at_[hidden])
Date: 2010-03-10 17:18:32

I was looking for a way to check how many entries are mapped in any given 
sparse vector and, as the documentation doesn't mention anything related to 
this, I've combed through the vector_sparse.hpp source file.  

While browsing the code I've stumbled on the nnz() method, which is defined in 
all sparse vector classes.  After testing it it appears that it does exactly 
what I was searching for.  Nonetheless, as it's an undocumented method, I was 
left wondering if it's results are meaningful or even if it works at all.

So, can anyone help?  Does the nnz() method return the number of mapped 
elements?  If not, is there any way to access that information?

Thanks in advance,
Rui Maciel