Re: [Linuxptp-users] Linear regression or pi?

[Ledda W. E. <Wil...@it...>]

Thank you Miroslav, 
Very useful explanation


William LEDDA
-----Original Message-----
From: Miroslav Lichvar [mailto:mli...@re...] 
Sent: 18 February 2015 18:17
To: Ledda William EXT
Cc: lin...@li...
Subject: Re: [Linuxptp-users] Linear regression or pi?

On Tue, Feb 17, 2015 at 12:43:50PM +0000, Ledda William EXT wrote:
> Dear linuxptp-users,
> I installed today linuxptp 1.5 to make some tests. I found that it is possible to use two different servos with phc2sys. I was using a version based on 1.3 and I found that the pi works fine for me. So which is the best? Or better... when one is preferable to the other? Which are the pros and cons?

The main advantage of linreg over pi is that it doesn't require any configuration for good performance, it works well in a wide range of conditions. The disadvantage is that it's much more heavy on math.
Unless it's running on an extremely slow cpu with software floating point, I'd not expect this to be a problem.

My recommendation is: if you care about accuracy and you can find good PI constants for your conditions, use pi. Otherwise use linreg.

--
Miroslav Lichvar