[R-sig-Geo] problems with dnearneigh of spdep

[Stephane DRAY]

Hello,
I have some strange results with the dnearneigh function.
I would like to have all points of grid linked. I do something like that:

 > xy=expand.grid(1:10,1:10)
 > mydnn=dnearneigh(as.matrix(xy),d1=0,d2=50)
 > mydnn
Neighbour list object:
Number of regions: 100
Number of nonzero links: 9896
Percentage nonzero weights: 98.96
Average number of links: 98.96
I assume to have 100*100-100=9900 links.

 > m01=nb2mat(mydnn,style="B")
 > apply(m01,1,sum)
   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18 
19  20  21  22  23  24  25  26  27
  98  99  99  99  99  99  99  99  99  98  99  99  99  99  99  99  99  99 
99  99  99  99  99  99  99  99  99
  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45 
46  47  48  49  50  51  52  53  54
  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99 
99  99  99  99  99  99  99  99  99
  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72 
73  74  75  76  77  78  79  80  81
  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99  99 
99  99  99  99  99  99  99  99  99
  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99 100
  99  99  99  99  99  99  99  99  99  98  99  99  99  99  99  99  99  99  98

It seems that the first and the last points are not linked. I have choose a 
value of d2 very high, and the distance between this two points is only 
sqrt(162)

Any ideas ?
Thanks
Stéphane DRAY
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Département des Sciences Biologiques
Université de Montréal, C.P. 6128, succursale centre-ville
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E-mail : stephane.dray at umontreal.ca
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