earth Package question for running a loop
Haven't used earth/MARS in a month or two, but I don't remember this being a big issue. Wouldn't... names(vars) ...do it for you? Cheers! Nick
On 2/20/12 6:26 PM, Ona Strikas wrote:
I don't know if anyone on the list uses the package earth to run a MARS analysis, but I am trying to run a loop of MARS runs and table the variables that it selects as explanatory. However, looking at the help file and names for an earth model, I can't find a good way of obtaining the variable names that it selects. Here are my present attempts: #attempt 1 vars = character()
set.seed(3042)
for(j in 1:1000){
+ rows = sample(1:length(rd4km$OBJECTID), 2000, replace=FALSE) + subrd4km = rd4km[rows, ] + model = earth(ff2006 ~ roadlength+Atl.dist+Atl.dir+roadd+easting+northing, degree=1, + data=subrd4km, glm=list(family=poisson)) + vars=c(vars, rownames(model$glm.coefficients)) + + }
head(table(vars))
vars
(Intercept) Atl.dirN Atl.dirNE
1000 99 629
Atl.dirNW Atl.dirS Atl.dirSE
571 882 55
Atl.dirSW Atl.dirW h(-0.574228-easting)
79 188 3
h(-100.574-easting) h(-104.574-easting) h(-108.574-easting)
1 1 5
h(-112.574-easting) h(-116.574-easting) h(-12.5742-easting)
# attempt 2
dirf = character()
set.seed(3042)
for(j in 1:1000){
rows = sample(1:length(rd5$X), 2000, replace=FALSE)
subrd5 = rd5[rows, ]
model = earth(ff ~ roadd + Atldir, degree=1,
data=subrd5, glm=list(family="poisson"))
dirf = c(dirf,
dimnames(model$coefficients)[[1]][length(dimnames(model$coefficients)[[1]])])
}
table(dirf)
The data is lightning flash density with a list of possible covariates.
Thanks for any help,
Sincerely,
Ona Strikas
Florida State University
Department of Geography
Graduate Student
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==================================================== Nicholas J. Matzke Ph.D. Candidate, Graduate Student Researcher Huelsenbeck Lab Center for Theoretical Evolutionary Genomics 4151 VLSB (Valley Life Sciences Building) Department of Integrative Biology University of California, Berkeley Graduate Student Instructor, IB200B Principles of Phylogenetics: Ecology and Evolution http://ib.berkeley.edu/courses/ib200b/ http://phylo.wikidot.com/ Lab websites: http://ib.berkeley.edu/people/lab_detail.php?lab=54 http://fisher.berkeley.edu/cteg/hlab.html Dept. personal page: http://ib.berkeley.edu/people/students/person_detail.php?person=370 Lab personal page: http://fisher.berkeley.edu/cteg/members/matzke.html Lab phone: 510-643-6299 Dept. fax: 510-643-6264 Cell phone: 510-301-0179 Email: matzke at berkeley.edu Mailing address: Department of Integrative Biology 1005 Valley Life Sciences Building #3140 Berkeley, CA 94720-3140 ----------------------------------------------------- "[W]hen people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together." Isaac Asimov (1989). "The Relativity of Wrong." The Skeptical Inquirer, 14(1), 35-44. Fall 1989. http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm