Re: Unexpected behaviour of PREDICT and PREDICTSIGMA

Steve Shipway <[email protected]> Sat, 26 Apr 2014 09:02:49 +0000

Newsgroups	gmane.comp.db.rrdtool.devel
Message-ID	<5820DC553954E44FA1A36C78323AD1483A304F6D@uxcn10-tdc06.UoA.auckland.ac.nz>

So, assuming stptr is zero based, this means my `analysis of the behaviour of negative shift counts is correct.

My question, though, is more to ask if this was intended by design, or if it is a 'feature'?

Intuitively, I would have expected this:

CDEF:y=s,-n,x,PREDICT

to result in shifts of s, 2s, 3s, .... ns

However, it actually results in shifts of 0, s, 2s, ... (n-1)s

Either way, it can't be changed now as it would potentially alter existing behaviour... 

Steve

Steve Shipway
University of Auckland ITS
UNIX Systems Design Lead
[email protected]
Ph: +64 9 373 7599 ext 86487