Dear,

Thank you for the help.

1. distance threshold
It is 9. (Roger, you are right and sorry to confuse you)

9 is the cutting point for avoiding empty neighbour sets.
(If the distance threshold is 8, there will be empty ones.)

2. dataset
length(nb10)=4873.
sum(card(nb10)=885478)

3. memory size
the memory limit is 1535 Mb, which is much larger than 121.8 Mb.


Elaine


Code

> library(ncf)
> library(spdep)
>
> # Define coordinates, neighbours, and spatial weights
> coords<-cbind(datam$lat,datam$lon)
> coords<-as.matrix(coords)
>
> #Define neighbourhood (here distance 1.5)
> nb10<-dnearneigh(coords,0,9)
> nb10.w<-nb2listw(nb10, glist=NULL, style="W", zero.policy=FALSE)
> sem.nb10.w <-
>
errorsarlm(datam$WinterM_ratio~datam$topo_mean+datam$coast+datam$prec_max
+datam$temp_min+datam$evi_min, listw=nb10.w,
method="Chebyshev",tol.solve=1.0e-17)
error: cannot allocate vector of size 121.8 Mb

sem.nb10.w <-
>
errorsarlm(datam$WinterM_ratio~datam$topo_mean+datam$coast+datam$prec_max
+datam$temp_min+datam$evi_min, listw=nb10.w,
method="Chebyshev",zero.policy=TRUE,tol.solve=1.0e-17)
error in switch(Generic, `+` = , `-` = { :
 Cholmod error 'out of memory' at file:../Core/cholmod_memory.c, line 148


On Sat, Jul 17, 2010 at 3:52 AM, Roger Bivand <Roger.Bivand@nhh.no> wrote:

> On Fri, 16 Jul 2010, elaine kuo wrote:
>
>  Dear List,
>>
>> I encountered an error message when trying to use Chebyshev as method for
>> SAR.
>> Please kindly help and thanks.
>>
>
> Beyond what Danlin said, I am very unsure where to start. Please provide
> adequate information about your input data, specifically the number of
> observations, and the number of links in the neighbour list
>
> length(nb10)
> sum(card(nb10))
>
> In addition, the implicit discription of nb10 looks confusing (is the
> distance threshold 1.5, 9, or 10?). The ordering of lat and lon looks wrong.
> You are not using Great Circle distances (and probably should?). So memory
> issues in errorsarlm are the least of your problems. My guess is that with
> dnearneigh() and a threshold of 9 degrees, you are including most of a large
> data set in the neighbour list, and if n is large, this will give a very
> large almost dense set of spatial weights, which was not what you intended.
>
> Get the weights correct first, and the rest will likely follow.
>
> Roger
>
>
>
>> package spdep was updated on 07162010
>> system: windows vista home 32-bit
>> R version 2.10.0 (20091026)
>>
>> Elaine
>>
>> Code
>>
>>> library(ncf)
>>> library(spdep)
>>>
>>> # Define coordinates, neighbours, and spatial weights
>>> coords<-cbind(datam$lat,datam$lon)
>>> coords<-as.matrix(coords)
>>>
>>> #Define neighbourhood (here distance 1.5)
>>> nb10<-dnearneigh(coords,0,9)
>>> nb10.w<-nb2listw(nb10, glist=NULL, style="W", zero.policy=FALSE)
>>> sem.nb10.w <-
>>>
>> errorsarlm(datam$WinterM_ratio~datam$topo_mean+datam$coast+datam$prec_max
>> +datam$temp_min+datam$evi_min, listw=nb10.w,
>> method="Chebyshev",tol.solve=1.0e-17)
>> error: cannot allocate vector of size 121.8 Mb
>>
>>  sem.nb10.w <-
>>>
>> errorsarlm(datam$WinterM_ratio~datam$topo_mean+datam$coast+datam$prec_max
>> +datam$temp_min+datam$evi_min, listw=nb10.w,
>> method="Chebyshev",zero.policy=TRUE,tol.solve=1.0e-17)
>> error in switch(Generic, `+` = , `-` = { :
>>  Cholmod error 'out of memory' at file:../Core/cholmod_memory.c, line 148
>>
>>        [[alternative HTML version deleted]]
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> R-sig-Geo@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, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand@nhh.no
>
>

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