trouble with point in polyhedron computation

sessionInfo()

library("alphashape3d?)

Hi,
If i got it right, the original question can be addressed somewhat with inashape3d (alphashape3d package), something like:
library(alphashape3d)
set1 <- matrix(rnorm(333)/2,ncol=3)
plot3d(set1)
ashape3d.obj <- ashape3d(set1, alpha = 2)
set2 <- matrix(rnorm(33)/2,ncol=3)
in3d <- inashape3d(ashape3d.obj, points = set2)
plot(ashape3d.obj, transparency = 0.2)
rgl.points(points[in3d,], col ="blue")

On Thursday, April 3, 2014 07:38 CEST, Don McKenzie <dmck at u.washington.edu> wrote: 

Thank you for the pointer.  That?s quite a list, and I expect I will have to concede defeat, lacking the skill set to adapt my use of the package.

On Apr 2, 2014, at 9:11 PM, Prof Brian Ripley <ripley at stats.ox.ac.uk> wrote:

Package ptinpoly has generated hangs/segfaults in its checks for years, across platforms.  That is why there are all the exclusions at http://cran.r-project.org/web/checks/check_results_ptinpoly.html .

On 03/04/2014 01:48, Don McKenzie wrote:

I have a 3D ordination with two groups, and want to identify the points in one group that lie within the 3D convex hull of the other. I would appreciate any enlightenment about why the command at the end (below in a toy example) crashes R when I try to ID the points in the hull using pip3d(), from package ptinpoly. convhulln() is from package geometry.  Have I not supplied the right ?Faces? argument to pip3d()?

The objects are not large and are reproduced at the bottom of this message.

Thanks

------------------------

sessionInfo()

R version 3.0.3 (2014-03-06)
Platform: x86_64-apple-darwin10.8.0 (64-bit)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] ptinpoly_2.0   misc3d_0.8-4   geometry_0.3-4 magic_1.5-6    abind_1.4-0

loaded via a namespace (and not attached):
[1] tools_3.0.3

??

set1 <- matrix(rnorm(99),ncol=3)
ch1 <- convhulln(set1)

Output completed.  Verifying that all points are below outer planes of
all facets.  Will make 594 distance computations.

set2 <- matrix(rnorm(33)/2,ncol=3)

temp.out <- pip3d(set1,ch1,set2)

R CRASHES HERE

----------------------------------


Don McKenzie
Research Ecologist
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Professor
School of Environmental and Forest Sciences
University of Washington
dmck at uw.edu



????????????????

set1
            [,1]        [,2]        [,3]
[1,] -0.36381788  0.96624676 -1.09251167
[2,] -1.09242946 -0.82002293  0.42005666
[3,]  0.93852498  1.18059117 -0.34816811
[4,] -0.77413132  1.06018374 -0.37589340
[5,] -1.67759103 -1.52469985  0.85310979
[6,]  0.81729494 -0.18900503  0.83172169
[7,]  0.30546957  0.97549183 -1.30815121
[8,]  0.22201517 -0.38260850 -0.05412764
[9,]  0.48817331  1.30314678  0.19143994
[10,]  1.89836307 -0.34575059  0.55599170
[11,]  0.20776401  0.04977816 -0.78034565
[12,] -0.76819740  0.24554574  0.40398017
[13,]  0.38369531  1.07688341 -0.22686023
[14,]  0.31806928  1.15482656 -0.99259846
[15,]  1.07142182 -1.03495199 -0.15650968
[16,] -1.24667302 -0.35217160  0.71090188
[17,] -0.92079326 -1.44075490 -0.42838857
[18,]  0.16907840  0.37587569  1.34994069
[19,]  0.50947015  1.81852997 -1.83315646
[20,]  0.52015187  1.56904146  0.90679914
[21,] -0.04261864 -1.22145642  0.51953397
[22,] -0.86611946 -1.21106313 -0.86571463
[23,] -0.13147715  0.07893287  0.83513033
[24,] -0.63488792 -0.89396994  0.70103420
[25,] -0.11370015  2.00351619 -0.17652412
[26,] -1.04527261 -0.14570830  1.64893662
[27,]  0.46238598 -0.07990767  0.16431874
[28,] -0.72396505  1.45081393 -0.91068823
[29,] -0.48892499 -1.05289633  1.36531224
[30,]  1.83781721  1.50964339  1.85100986
[31,]  1.00023790 -0.92779325 -2.16783507
[32,] -0.51429532 -1.44766548 -1.41456589
[33,] -0.93249545 -0.21845332  0.75023990

ch1

     [,1] [,2] [,3]
[1,]   15   31   10
[2,]   29   30   10
[3,]   29   15   10
[4,]   26   28   25
[5,]   26   29    5
[6,]   26   29   30
[7,]   32   15   31
[8,]   19   28   25
[9,]   19   32   31
[10,]   19   32   28
[11,]   19   30   25
[12,]   19   31   10
[13,]   19   30   10
[14,]   21   29    5
[15,]   21   29   15
[16,]   21   32    5
[17,]   21   32   15
[18,]   20   30   25
[19,]   20   26   25
[20,]   20   26   30
[21,]   16   28    5
[22,]   16   26    5
[23,]   16   26   28
[24,]   22   28    5
[25,]   22   32    5
[26,]   22   32   28

set2

             [,1]         [,2]        [,3]
[1,]  0.061298933  0.561676607 -0.29029312
[2,] -0.227292687  0.980185118  0.21751216
[3,]  0.182482967  0.913803801 -0.08308208
[4,] -0.143596376 -0.007469921 -0.33050543
[5,] -0.354096826  0.023132113  0.45463150
[6,]  0.006247011  0.183155253  0.97496500
[7,]  0.128600720 -0.249603537 -0.24710206
[8,] -0.418782299 -0.325201099  0.28908138
[9,]  0.231829464  0.343250895  0.65134735
[10,] -0.392597726  0.126741875  0.21411363
[11,] -0.051290704 -1.007826669  0.92808143

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

Don McKenzie
Research Ecologist
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Professor
School of Environmental and Forest Sciences
University of Washington
dmck at uw.edu





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