Hi list. This is not exactly a "grass-"stats topic but I require help to cross-compare results from a custom R function I wrote. Since many spatial analysts read this list, I guess that there is a good chance that someone experienced can help me out.
I calculate via a function various separability indices or distances for samples between classes, namely: Bhattacharrya, Jeffries-Matusita, Divergence and Transformed Divergence (...it's true that I have posted about the Bhattacharyya distance in the past in this list [2]). I need to verify the reliability of the function. I don't know of any R package or other tool to get those measures quickly calculated. The one (foss- tool) I found that contains a function to calculate the Divergence is the LAS [2]. But I have trouble getting it compiled under bash. The function and a call for help is posted already in r-help _at_ r- project.org [3]. Does anybody have access to any tool that could quickly calculate those indices (actually just the Divergence and the Bhattacharryya would be enough)? Thank you, Nikos --%<--- Two small samples (in R code style --- the same posted in r-help): # two samples sample.1 <- c (1362, 1411, 1457, 1735, 1621, 1621, 1791, 1863, 1863, 1838) sample.2 <- c (1354, 1458, 1458, 1458, 1550, 1145, 1428, 1573, 1573, 1657) # running the custom function (posted in r-help) separability.measures ( sample.1 , sample.2 ) Divergence: 1.5658 Bhattacharryya: 0.1683 Jeffries-Matusita: 0.3098 Transformed divergence: 0.3555 --%<--- [1] http://osgeo-org.1803224.n2.nabble.com/How-to-calculate-the-Bhattacharyya- distance-index-td2317804.html [2] ftp://dbftp.essc.psu.edu/pub/code/las [3] http://n4.nabble.com/Cross-checking-a-custom-function-for-separability- indices-td2019342.html#a2019342 _______________________________________________ grass-stats mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-stats
