error in errorsarlm
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
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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 at nhh.no