[ublas] Add squared norm convenience function

Subject: [ublas] Add squared norm convenience function
From: Ronald Wampler (rdwampler_at_[hidden])
Date: 2016-03-07 13:03:00

Hi,

I was wondering if it would be possible to add a function to calculate
the squared norm? While it's easy to implement one's own version,
it occurs fairly frequently (e.g., in optimization problems) that it
would be nice to have. I would be happy to provide a patch if there is
interest.

Ron