Re: [boost] interest on a geometry library

From: Andy Little (andy_at_[hidden])
Date: 2006-03-20 21:00:43

"Janek Kozicki" wrote
> Andy Little said:     (by the date of Mon, 20 Mar 2006 14:14:28 -0000)
>
>> > I will try to help you with that geometry library, because I want to
>> > use boost too, instead of dragging everywhere similar library
>> > (with quaternions, and all that 3D stuff). I'm mainly using that library
>> > for discrete simulation modelling (shameless plug:
>> > http://yade.berlios.de/ ).
>> > So I'm comparing your work against mine :)
>>
>> Wow. It looks impressive. I note the intention in the schedule; Milestone 4
>> to
>> "Use physical units, from dimnum or SIunits library".
>> What is the status of that? Naturally having spent some time on proposed
>> Boost
>> Pqs library  http://tinyurl.com/7m5l8I would be interested to see if it might
>> be
>> used for this purpose.
>
> well no progress on the front of physical units :) I was searching for
> some useful physical units library and found those two. I also found
> your pqs library, but (a year ago) after a brief look at it I decided
> against it. But now that's the history :) When I have a direct contact
> with the library author (you), and because Pqs will be a part of boost -

The situation is that pqs is in the queue to reviewed to be part of boost. I
have no idea what the outcome of the review will be.

> suddenly Pqs has huge advantage over other libraries, so I will try to
> use it :) But not now, it is a future target ;) That URL
> http://tinyurl.com/7m5l8I is not working....

Sorry ... should be pqs_3_0_6 at  http://tinyurl.com/7m5l8

[...]

> sorry that this post got so incredibly long ;)

No problem. I will try to reply to the other parts of your post in more detail
soon.  Overall I can see a good deal of divergence between your aims and mine.
(That is not necessarily a bad thing of course as we would presumably be aiming
for the most widespread use). Your applications require very good raw speed
performance, which I havent paid enough attention to, but I can see now why you
will be obsessed with that from looking at YADE. Overall I have been looking at
ease of use. I am currently interested in integrating geometry /vectors with pqs
library, but that would increase complexity of the implementation over just
using float types as you may see in my current geometry offering and will also
affect compile times, so may be a burden giving you  no benefit.  That
difference of quaternions v matrices is interesting also. The generic nature of
matrix transforms is at the expense of speed. It should be possible to combine
both matrix and quaternions transforms somehow of course and I will have to read
up on using quaternion.  It strikes me that perhaps more detailed discussion
about  the goals and rationale of such a library is needed too.

As to quanternion...is boost::quanternion not suitable for your applications as
it stands?

regards
Andy Little