[R-sig-Geo] problems with dnearneigh of spdep
Roger Bivand
Roger.Bivand at nhh.no
Sat Oct 30 09:12:25 CEST 2004
On Fri, 29 Oct 2004, Roger Bivand wrote:
> On Fri, 29 Oct 2004, Stephane DRAY wrote:
>
> > My version :
> >
> > > version
> > _
> > platform i386-pc-mingw32
> > arch i386
> > os mingw32
> > system i386, mingw32
> > status
> > major 1
> > minor 9.1
> > year 2004
> > month 06
> > day 21
> > language R
> > > spdep()
> > [1] "spdep, version 0.2-18, 2004-05-25"
> > > sum(card(mydnn))
> > [1] 9896
> > > all(sapply(mydnn, length) == 99)
> > [1] FALSE
>
> I can replicate on Windows, R 1.9.1, spdep 0.2-18. I'll report back on R
> 2.0.0, spdep 0.2-22 in a little while.
It also replicates with fresh binaries on:
> spdep()
[1] "spdep, version 0.2-22, 2004-08-07"
> version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 0.0
year 2004
month 10
day 04
language R
> 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'll look and see what is going on, thanks for the bug report.
Roger
>
> Roger
>
> >
> > It is not the last one, I will try to update later. I think that the
> > problem is in the calculation of neighbors. Perhaps, the fortran code has
> > changed. I do not have the sources, so I could not verify.
> >
> > Thanks !
> >
> >
> >
> > At 13:01 29/10/2004, Roger Bivand wrote:
> > >On Fri, 29 Oct 2004, Stephane DRAY wrote:
> > >
> > > > 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)
> > >
> > >I can't replicate this:
> > >
> > > > version
> > > _
> > >platform i686-pc-linux-gnu
> > >arch i686
> > >os linux-gnu
> > >system i686, linux-gnu
> > >status
> > >major 2
> > >minor 0.0
> > >year 2004
> > >month 10
> > >day 04
> > >language R
> > > > library(spdep)
> > > > spdep()
> > >[1] "spdep, version 0.2-22, 2004-08-07"
> > > > 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: 9900
> > >Percentage nonzero weights: 99
> > >Average number of links: 99
> > >
> > >The line "Number of nonzero links:" is calculated as:
> > >
> > > > sum(card(mydnn))
> > >[1] 9900
> > >
> > >You can also look at:
> > >
> > > > all(sapply(mydnn, length) == 99)
> > >[1] TRUE
> > > > which(sapply(mydnn, length) != 99)
> > >numeric(0)
> > >
> > >if you want to be sure it isn't card() getting it wrong. Puzzling. I don't
> > >think any of the relevant code has changed since September 2003.
> > >
> > >Roger
> > >
> > > >
> > > > Any ideas ?
> > > > Thanks
> > > > Stéphane DRAY
> > > >
> > > --------------------------------------------------------------------------------------------------
> > >
> > > >
> > > > Département des Sciences Biologiques
> > > > Université de Montréal, C.P. 6128, succursale centre-ville
> > > > Montréal, Québec H3C 3J7, Canada
> > > >
> > > > Tel : (514) 343-6111 poste 1233 Fax : (514) 343-2293
> > > > E-mail : stephane.dray at umontreal.ca
> > > >
> > > --------------------------------------------------------------------------------------------------
> > >
> > > >
> > > >
> > > Web http://www.steph280.freesurf.fr/
> > > >
> > > > _______________________________________________
> > > > R-sig-Geo mailing list
> > > > R-sig-Geo at stat.math.ethz.ch
> > > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> > > >
> > >
> > >--
> > >Roger Bivand
> > >Economic Geography Section, Department of Economics, Norwegian School of
> > >Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
> > >Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
> > >e-mail: Roger.Bivand at nhh.no
> > >
> > >_______________________________________________
> > >R-sig-Geo mailing list
> > >R-sig-Geo at stat.math.ethz.ch
> > >https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
> > Stéphane DRAY
> > --------------------------------------------------------------------------------------------------
> >
> > Département des Sciences Biologiques
> > Université de Montréal, C.P. 6128, succursale centre-ville
> > Montréal, Québec H3C 3J7, Canada
> >
> > Tel : (514) 343-6111 poste 1233 Fax : (514) 343-2293
> > E-mail : stephane.dray at umontreal.ca
> > --------------------------------------------------------------------------------------------------
> >
> > Web http://www.steph280.freesurf.fr/
> > --------------------------------------------------------------------------------------------------
> >
> >
> >
>
>
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no
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