[R-sig-Geo] error message when running errorsarlm

evans324 at umn.edu evans324 at umn.edu
Tue May 20 21:29:50 CEST 2008

Thanks for your response.  Here's what I have now.  

On May 20 2008, Roger Bivand wrote:

>A bit more context would help. The output of sessionInfo() at least (R and 
>package versions may matter), plus the preceding code, including the 
>definition of rams_dak.dnear3k.listw - is it row-standardised? 

Output of sessionInfo():
R version 2.6.1 (2007-11-26) 

locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United 
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] spdep_0.4-17 Matrix_0.999375-5 lattice_0.17-2 spam_0.13-2 boot_1.2-30 
 [7] foreign_0.8-23    sp_0.9-23         tripack_1.2-11    car_1.2-7        

loaded via a namespace (and not attached):
[1] grid_2.6.1  tools_2.6.1

Preceding code:
rams_dak <-readShapePoly("rams_dak_6May.shp", IDvar="ID", verbose=TRUE)
rn<-sapply(slot(rams_dak, "polygons"), function(x) slot(x, "ID"))
rams_dak.dnear.nb <- dnearneigh(coords, 0, 2500, row.names=rn)
rams_dak.dnaer.listw <- nb2listw(rams_dak.dnear.nb, zero.policy=TRUE)

> Running traceback() immediately after the error would also be helpful to 
> see where in functions called by sar.error.f.M() the problem is 
> occurring.

I get:
2: stop(gettextf("no method or default for coercing \"%s\" to \"%s\"", 
       thisClass, Class), domain = NA)
1: as((I - lambda * csrw), "dsCMatrix")

> If I understand correctly, the error messages cycle, but the 
> rams_dak3k.err >object is created?

>Could you run it with quiet=FALSE, so see the function values as they are  
>generated in optimize()? The NAs usually come from the  
>interval= being too broad wrt. your weights style.

I did this and found that lambda ranged from -.2364499 to .999 with SSEs 
starting at 292.339 and going to 267.4409. I a bit unsure of how to select 
and interval. Can you offer some advice on this?

Thanks for your help.


Heather Sander
Ph.D. Candidate:  Conservation Biology
Office:  305 Ecology & 420 Blegen
University of Minnesota
Dept. of Geography
414 Social Science Bldg.
267 19th Ave. S.
Minneapolis, MN 55455

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