[R] Histogram equalization of dataset
I read about histogram equalization of dataset. It is commonly used for image data. It is written: Each variable in dataset is assigned to one bin. Then, each variable in the dataset is assigned to one bin, incrementing the value of that bin by one. Then, a cumulative histogram is created by adding to each bin the value of its preceding bins. Finaly, the value of each bin is divided by the total number of observations, thus standardizing the data within the interval of [0,1]. Could you show me how to get it? If a have a dataset below: X1 X2 Min. :-4.37371 Min. :-27.84627 1st Qu.:-0.205581st Qu.: 0.0 Median :-0.01528 Median : 0.07848 Mean :-0.04896 Mean : 0.02751 3rd Qu.: 0.14511 3rd Qu.: 0.28831 Max. : 0.78047 Max. : 0.89851 -- View this message in context: http://r.789695.n4.nabble.com/Histogram-equalization-of-dataset-tp4661887.html Sent from the R help mailing list archive at Nabble.com. __ 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.
[R] Feature selection for kmeans
I know that within sum of squares, DB, sillhouette and cophenetic are indicators of clustering quality, but what indicators I need to observe when I choose attributes for kmeans? -- View this message in context: http://r.789695.n4.nabble.com/Feature-selection-for-kmeans-tp4657830.html Sent from the R help mailing list archive at Nabble.com. __ 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.
[R] What methods you use for choosing attributes for kmeans and other clustering (unsupervised) methods?
What characteristics makes attribute great for kmeans clustering and how do you measure these characteristics? Do you look at the distribution shape, correlation matrix between attributes, pairs graphs, statistical tests...? -- View this message in context: http://r.789695.n4.nabble.com/What-methods-you-use-for-choosing-attributes-for-kmeans-and-other-clustering-unsupervised-methods-tp4657464.html Sent from the R help mailing list archive at Nabble.com. __ 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.
