dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

On Monday August 22 2011 12:21:29 Andre Massing wrote:
> On 08/22/2011 07:44 PM, Johan Hake wrote:
> > On Monday August 22 2011 10:39:33 Anders Logg wrote:
> >> On Mon, Aug 22, 2011 at 10:22:44AM -0700, Johan Hake wrote:
> >>> Hello!
> >>> 
> >>> A recent email discussion with Andre made me aware (again) of
> >>> the incompatability between QPL and GPL. Not sure we have
> >>> settled this issued, but
> >>> 
> >>> I googled it and found the following link:
> >>> http://www.gnu.org/licenses/license-list.html
> >>> 
> >>> scroll down to QPL. Here they suggest the following solution:
> >>> However, if you have written a program that uses QPL-covered
> >>> library (called FOO), and you want to release your program
> >>> under the GNU GPL, you can easily do that. You can resolve the
> >>> conflict for your program
> >>> 
> >>> by adding a notice like this to it: As a special exception, you
> >>> have permission to link this program with the FOO library and
> >>> distribute executables, as long as you follow the requirements
> >>> of the GNU GPL in regard to all of the software in the
> >>> executable aside from FOO.
> >>> 
> >>> You can do this, legally, if you are the copyright holder for
> >>> the program. Add it in the source files, after the notice that
> >>> says the program is covered by the GNU GPL.
> >>> 
> >>> For this to work all copyright holders need to agree. Not sure
> >>> we need another author content process to use this solution
> >>> though.
> >> 
> >> Andre also mentioned to me that we actually don't need those
> >> special QPL pieces of CGAL (but can use GTS instead with improved
> >> efficiency) so it might not be a problem. Andre knows more about
> >> this.
> > 
> > Then we "just" need to reimplement that part... Sounds tedious.
> 
> Yes and No.  I have already done a substantial part along the way
> while I worked on my overlapping mesh implementation. For the
> collision detection part I don't see any problems. But I have to
> investigate
> the distance computation part a bit. There exists some functionality
> in GTS, but you have to supply some distance function, computing
> distance between a query object and a entity.

I think CGAL does it by first computing a closest entity in a tree from a 
point. The distance is then computed by evaluating the euclidian distance 
between these the entity and the point.

What part of this chain is needed to get GTS to compute distances?

Johan

> > Johan
> > 
> >> -- Anders
> > 
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