I'm a bit confused why the following command is taking an extrodinarily
long time (> 2-3 hours) to run on an 3.06ghz iMac (brand new). I'm
trying to do a stratified random sample, drawing only a single value per
UniqueID from the patch_summary data frame:
uniqueids <- unique(patch_summary$UniqueID)
uniqueids_stratasize <- c(1:length(uniqueids))*0+1
temp_species_patch_random_strata <-
strata(patch_summary,c("UniqueID"),size=uniqueids_stratasize)
The patch_summary data frame is too big to include in this email, but
I'll give some summary results for the inputs. patch_summary has 48253
rows, UniqueID has 661 levels, and uniqueid_stratasize is a vector if
661 "1"s (corresponding to the 661 levels from UniqueID -- as I said I
only want one per UniqueID).
Am I doing something silly here? Am I using the wrong stratified
sampling algorithm? Any help would be appreciated -- thanks -- I don't
see why a stratified sampling would take hours to run -- I am about to
recode this as a series of subset statements which I'm sure will take
only minutes...
--j
--
Jonathan A. Greenberg, PhD
Postdoctoral Scholar
Center for Spatial Technologies and Remote Sensing (CSTARS)
University of California, Davis
One Shields Avenue
The Barn, Room 250N
Davis, CA 95616
Cell: 415-794-5043
AIM: jgrn307, MSN: jgrn...@hotmail.com, Gchat: jgrn307
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