[MOAB-dev] Bug in kdtree?

[Iulian Grindeanu]

so the entities come out ordered according to the distance only if the max_ints is set. 
(only the first max_ints are returned, with the closest distance from the source of the ray) 
The bug is fixed now. 

So do you think that we should order them in all cases, for consistency? 

That makes sense. 

Iulian 

----- Original Message -----

| I do think the entries should be ordered at the end of the call,
| after tree traversal is done, though.

| - tim

| On 07/24/2013 04:35 PM, Iulian Grindeanu wrote:
| > the bug is around that logic, that I try to understand.
| > It seems that the "ray_end" is reset, which is why some points are
| > missed.
| >
| > I didn't write that logic, maybe Tim or Paul know who did.
| >
| > I don't think we should guarantee the order;
| > The user should order it if needed;
| >
| > The "leafs" of the tree can come in any order, and we should not
| > try to order it there.
| >
| > Iulian
| >
| > ------------------------------------------------------------------------------------------------------------------------
| >
| >
| > Hi iulian
| >
| > Thanks for that, additional side question. When you specify the
| > maximum number of intersection to return, the list
| > is ordered in distance from the start point, when you specify 0,
| > the list is unordered. Should we not expect
| > consistent behavior in both cases?
| >
| > Thanks
| >
| > Andy
| >
| >
| >
| > Sent from my Samsung Galaxy Note™, an AT&T LTE smartphone
| >
| > Iulian Grindeanu <iulian at mcs.anl.gov> wrote:
| > it works fine if you do not specify the limit 100 for number of
| > intersections.
| > If you leave it 0, it is fine;
| > (so call with kdtree->ray_intersect_triangles( kdtree_root, 1.0e-6,
| > dir, box_center,
| > intersection_facets
| > , intersections);
| >
| > I am still looking, but I think I am close :)
| >
| > ------------------------------------------------------------------------------------------------------------------------
| >
| > OK, obb tree works fine with the same model, default setting for
| > everything
| > (you do no have to put tetras in the build, only the faces)
| >
| > So there might be an issue with the kdtree.
| > I will look at it.
| >
| > Iulian
| > ------------------------------------------------------------------------------------------------------------------------
| >
| > The problem is on the secondrun, moving the starting point in the
| > to y=4, then we get no intersections
| > beyond 48.5.
| > On 07/24/2013 10:50 AM, Iulian Grindeanu wrote:
| >
| > I see no error
| > Your fifth slab is at about 49.5;
| > (first at 9.5, ..., fifth at 49.5)
| >
| > Iulian
| >
| > ------------------------------------------------------------------------------------------------------------------------
| >
| > I think I may have found a bug in kdtree.
| >
| > My test problem consists of a tet mesh that is composed of some
| > 4000
| > tets. The mesh looks like that in mesh.png, a ray starts at
| > position
| > (1,0,0) and fires along (1,0,0) and we get the following results
| > back
| > from my test program swp.cpp
| >
| > Compile the minimum working example as
| >
| > g++ swp.cpp -I/<moab include dir> -L<moab lib dir> -lMOAB
| >
| >
| > This is as expected,
| >
| > # of intersections : 20
| > intersection distances are on 8.5 8.74072 9.25928 9.5 18.5 18.7407
| > 19.2593 19.5 28.5 28.7407 29.2593 29.5 38.5 38.7407 39.2593 39.5
| > 48.5
| > 48.7407 49.2593 49.5 of ray length 900
| >
| > 8.5 9.5 18.5 19.5 etc are the boundaries of the faces of the mesh.
| >
| > However, if we recompile and change the starting position to
| > (1,4,0) we get
| >
| > # of intersections : 17
| > intersection distances are on 8.5 8.63513 9.06064 9.5 18.5 18.6351
| > 19.0606 19.5 28.5 28.6351 29.0606 29.5 38.5 38.6351 39.0606 39.5
| > 48.5 of
| > ray length 900
| >
| > As far this ray is concerned there is no mesh in the 5th slab.
| >
| > What have I done wrong?
| >
| > Thanks
| >
| > Andy
| >
| >
| >
| >
| >
| >

| --
| ================================================================
| "You will keep in perfect peace him whose mind is
| steadfast, because he trusts in you." Isaiah 26:3

| Tim Tautges Argonne National Laboratory
| (tautges at mcs.anl.gov) (telecommuting from UW-Madison)
| phone (gvoice): (608) 354-1459 1500 Engineering Dr.
| fax: (608) 263-4499 Madison, WI 53706
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/moab-dev/attachments/20130725/e7d6bdc5/attachment.html>