similar to: Simple question about extracting a subset of data

Hello, I've come across a problem in developing a set of custom functions to calculate the number of hours of daylight at a given latitude, and the number of days a date precedes or secedes the summer solstice. I discovered an inconsistency concerning leap years between my derived values and those from the US naval databases. It seems as far as I can figure that my inconsistency arises either

Hi there are some good tips in "The R Inferno" http://www.burns-stat.com/documents/books/the-r-inferno/ or connect C++ to R with Rcpp http://dirk.eddelbuettel.com/code/rcpp.html or byte code compiler (library(compiler)) or library(data.table) but do you have an idea to fasten standard R source code, with the following Rprof output self.time self.pct total.time

Dear List, I am having problems running stepAIC with a negative binomial regression model.  I am working with data on manta ray abundance, using 20 predictor variables.  Predictors include variables for location (site), time (year, cos and sin of calendar day, length of day, percent lunar illumination), oceanography (sea surface temp mean and std, sea surface height mean and std), weather (cos

V; Sent via BlackBerry from T-Mobile -----Original Message----- From: r-help-request at r-project.org Date: Tue, 30 Sep 2008 12:00:06 To: <r-help at r-project.org> Subject: R-help Digest, Vol 67, Issue 31 Send R-help mailing list submissions to r-help at r-project.org To subscribe or unsubscribe via the World Wide Web, visit https://stat.ethz.ch/mailman/listinfo/r-help or, via email,

Ben, I tried playing with the "na.action" but that didn't seem to help.  I didn't know of the na.omit function.  It made it much easier to get rid of all the missing values in the file, and now the regression model is running. I hadn't put interactions in the model yet since it wasn't even running.  Cosday, sinday, and daylength are strongly collinear.  The full model