[ITK] [ITK-users] Silly question on itk::Matrix

[vincent ngai]

Ah yes, so my question is why is the [] accessor not column major? If
points are columns, the matrix elements for the Tx,Ty,Tz translation
components should also be columnar? It just seems like extra work to need
to get the matrix transpose just to do a Mat * P

Regards,
Vincent


On Fri, Aug 22, 2014 at 7:14 PM, Jim Miller <millerjv at gmail.com> wrote:

> ITK standard is that points are column vectors. Thus, matrix times a point
> a point is defined as Mat * P
>
> Jim
>
> > On Aug 22, 2014, at 3:30 AM, vincent ngai <vincent.ngai at gmail.com>
> wrote:
> >
> > Hi all, pardon me for this silly question on itk::Matrix. Why do I need
> to transpose a translation matrix after I copy the [x,y,z] translation
> values to the matrix[3].
> >
> > I know conceptually it should not really matter whether its row or col
> major so long as you can
> > post multiply or pre multiply with another vector. But the way
> operator*() works only allows for
> > Matrix * P, and when I test the simple case of TranslationMatrix *
> Point, I would have to transpose the matrix. If I could also do Point *
> TranslationMatrix, then i wouldn't need to transpose.
> >
> > Any ideas?
> >
> > --
> > Regards,
> > Vincent
> > _____________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Kitware offers ITK Training Courses, for more information visit:
> > http://www.kitware.com/products/protraining.php
> >
> > Please keep messages on-topic and check the ITK FAQ at:
> > http://www.itk.org/Wiki/ITK_FAQ
> >
> > Follow this link to subscribe/unsubscribe:
> > http://public.kitware.com/mailman/listinfo/insight-users
>



-- 
Regards,
Vincent
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/community/attachments/20140823/62f530df/attachment-0002.html>
-------------- next part --------------
_____________________________________
Powered by www.kitware.com

Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html

Kitware offers ITK Training Courses, for more information visit:
http://www.kitware.com/products/protraining.php

Please keep messages on-topic and check the ITK FAQ at:
http://www.itk.org/Wiki/ITK_FAQ

Follow this link to subscribe/unsubscribe:
http://public.kitware.com/mailman/listinfo/insight-users