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Subject: Re: [boost] GSoC idea on Geometry library
From: Barend Gehrels (barend_at_[hidden])
Date: 2012-02-08 14:03:27

Hi Sultana,

Thanks for your ideas!

On 8-2-2012 8:49, sultana rashid wrote:
> Hello,
> I have several ideas on some libraries.Today I present on Geometry library.
> *1.Conics:*
> I did not found *conics* in Geometry library.Ellipse,parabola,hyperbola
> concept is very useful in geometry.Can Boost add some functionality of
> conics? as:
> 1.Area determination of conics
> 2.Foci determination
> 3.Major-minor axis
> 4.Determine whether a point on a conic
> 5.Focal length,center determination
> etc... etc...
> Or at least add something on Conic in Concept section?
> If this idea seems useful to you,please let me know.I will describe
> details on what I want to do about Conic section in Geometry library.

As Andrew also said, it might be a little more concrete. Besides this,
well it is geometry of course, but not on the real parts Boost.Geometry
is focussing on.

You would expect a Line concept (so an infinite line) or a Ray concept
earlier in Boost.Geometry than a Parabola. And these are not even there
(we do have a linestring which is a piece of finite segments, but that
is not a Line). So implementing these is maybe a step too far.

> *2. **Convex HUll: *There is only one algorithm implemented .We can
> implement *Gift wrapping*<>
> *O*(*nh*) ; *Divide and conquer* *O*(*n* log *n*) or *Chan's
> algorithm*<>
> *O*(*n* log *h*). Jarvis march ,Chan's algo are output sensitive.These are
> useful when we can assume that the result will not be too large.

Given the current state, this is not really an addition. The algorithm
we have is n log(n) and performs quite fast compared to other libraries
(when I checked it years ago). So there is no much to gain there.

There is enough to do though, and help is welcome. So I leave it for the
moment to you to inventarise the library and discover things that are
really useful in this stage. Note there are previous GSoC efforts which
still have to be finished and integrated, and also lack of some feedback
from our sides due to pressure on other parts (and it is all voluntary
work). So don't I want to discourage you but I want to be clear in what
is possible and probable, and what is not.

Regards, Barend

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