
Ublas : 
From: Paul C. Leopardi (leopardi_at_[hidden])
Date: 20050321 16:31:45
On Tue, 22 Mar 2005 03:30 am, Michael Stevens wrote:
> I was thinking of how to describe how the two index arrays are built and
> the invariant that 'complete_index1_data' enforces. That is to say if we
> keep the implementation where index1 may be incomplete we should somewhere
> document it. Do you know if any other compressed matrix libraries yield
> similarly incomplete index1 array?
Hi all,
Sorry to chime in at this late stage, but I have been quite confused by this
thread of discussion.
Is it possible/valid to have a compressed matrix where the index1 array is
complete and yet there are rows (or columns depending on type of compressed
matrix) which contain no nonzeros? A simple example would be the zero
matrix. Is is possible/valid to have a compressed matrix with no nonzeros
and yet a complete index1 array? If not, wouldn't this badly break the
expected linear algebra semantics of compressed matrices, eg. you would need
to force some of the nonzeros to have the value zero?
Thanks