[ODE] how to use the type dMatrix3

[Henri Hakl]

Just from the definition (dReal[12]) it is not clear whether it is in
row-major or column-major format. I'm not actually sure which is which - but
I'd guess that the example "[col*4+row] in general" indicates it is in
column-major format. (Though I'd be happy if somebody cleared that up for me
once and for all.)

(I've got a similar problem with BigEndian and SmallEndian notation. Which
is which, and what is the difference?)


----- Original Message -----
From: "David Whittaker" <david@csworkbench.com>
To: <ode@q12.org>
Sent: Saturday, April 26, 2003 7:55 PM
Subject: Re: [ODE] how to use the type dMatrix3


> dMatrix3 is defined as dReal[12].  So to access column 3, row 1, you would
> ask for [3*4+1], or [col*4+row] in general.  Why the strangeness?  It's a
> 3x3 matrix with SIMD padding, so it needs to have rows of length 4.
>
> Hope that helps,
> David
>
> > Hi,
> > Does somebody know hot to use the type: dMatrix3?
> > Is it used as matrix or a vector?
> > If I want for example to get to cel (3,1) how do I do it?
> >
> > Thank you
> > Koby
> >
>
>
>
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