# [R] orientlib

Abu Naser likhonnaser at hotmail.com
Mon Oct 1 15:44:50 CEST 2007

```Hi Duncan,

I am confused as I dont have the quaternion backgorund.

Let me explain what I am trying to do:
I have 3 coordinates in  space (x1,y1,z1),(x2,y2,z2), and (x3,y3,z3) . Now, I use  (x1,y1,z1) and (x2,y2,z2) to define axis of rotaion. Then, I wanted to use 3rd coordinate to calculate angle of rotation about that axis. Is it possible with your orientlib?

With regards,
Abu

----------------------------------------> Date: Mon, 1 Oct 2007 06:50:35 -0400> From: murdoch at stats.uwo.ca> To: likhonnaser at hotmail.com> CC: r-help at r-project.org> Subject: Re: [R] orientlib>> On 01/10/2007 3:31 AM, Abu Naser wrote:>> Hi all users,>>>> I want to calculate angles from two vector using quaternion. I believe , it is possible using orientlib. Since>> I am not an quaternion expart, I need assistance to make sure I am not doing anything wrong. Could anyone please>> expain it how to do it using orientlib.>>> x <- quaternion(c(1,0,0,0))>> y <- quaternion(c(0,1,0,0))>> rotation.distance(x,y)> [1] 3.141593>> But this doesn't calculate angles between vectors, it calculates angles> between orientations. See>> Murdoch, D. (2003). Orientlib: an R package for orientation data.> Journal of Statistical Software, 8(19), 1-11.>> for details.>> Duncan Murdoch

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