[R] kde on Torus
Hello, I have 2D-data on a torus, i.e. they are scattered within [0:2pi) and are supposed to be periodic with period 2pi. Is there a way in R for a kernel density estimation for such data? I found this article http://www.dmqte.unich.it/personal/dimarzio/density46.pdf but a) I don't fully understand the article (my knowledge in statistics is poor) b) I did not understand which Eq. represents the kernel(s) c) I do not now R well enough to understand whether I can use kde2d or nprudens with an arbitrary kernel My simple-minded attempt was to extend the data to [-2pi:4pi) and then use kde2d, but I am wondering a) how accurate is this b) is there a way to do it properly on a torus. Thanks a lot, Tim -- -- Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A signature.asc Description: Digital signature __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] kde on Torus
On Jul 28, 2010, at 7:55 AM, Tim Gruene wrote: Hello, I have 2D-data on a torus, i.e. they are scattered within [0:2pi) and are supposed to be periodic with period 2pi. Is there a way in R for a kernel density estimation for such data? I found this article http://www.dmqte.unich.it/personal/dimarzio/density46.pdf but a) I don't fully understand the article (my knowledge in statistics is poor) b) I did not understand which Eq. represents the kernel(s) c) I do not now R well enough to understand whether I can use kde2d or nprudens with an arbitrary kernel My simple-minded attempt was to extend the data to [-2pi:4pi) and then use kde2d, but I am wondering a) how accurate is this b) is there a way to do it properly on a torus. You could take a look at the density function within the package, circular. -- David Winsemius, MD West Hartford, CT __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] kde on Torus
Dear David, thanks for the hint. As far as I understand the circular kernels apply only to one-dimensional data, don't they? Tim On Wed, Jul 28, 2010 at 08:57:40AM -0400, David Winsemius wrote: On Jul 28, 2010, at 7:55 AM, Tim Gruene wrote: Hello, I have 2D-data on a torus, i.e. they are scattered within [0:2pi) and are supposed to be periodic with period 2pi. Is there a way in R for a kernel density estimation for such data? I found this article http://www.dmqte.unich.it/personal/dimarzio/density46.pdf but a) I don't fully understand the article (my knowledge in statistics is poor) b) I did not understand which Eq. represents the kernel(s) c) I do not now R well enough to understand whether I can use kde2d or nprudens with an arbitrary kernel My simple-minded attempt was to extend the data to [-2pi:4pi) and then use kde2d, but I am wondering a) how accurate is this b) is there a way to do it properly on a torus. You could take a look at the density function within the package, circular. -- David Winsemius, MD West Hartford, CT -- -- Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A signature.asc Description: Digital signature __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
