[R-SIG-Mac] [R-sig-mac] trouble with point in polyhedron computation

[Don McKenzie]

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