dirichletprocess

The dirichletprocess package provides tools for you to build custom Dirichlet process mixture models. You can use the pre-built Normal/Weibull/Beta distributions or create your own following the instructions in the vignette. In as little as four lines of code you can be modelling your data non-parametrically.

Installation

You can install dirichletprocess from github with:

# install.packages("devtools")
devtools::install_github("dm13450/dirichletprocess")

For a full guide to the package and its capabilities please consult the vignette:

browseVignettes(package = "dirichletprocess")

Examples

Density Estimation

Dirichlet processes can be used for non-parametric density estimation.

faithfulTransformed <- faithful$waiting - mean(faithful$waiting)
faithfulTransformed <- faithfulTransformed/sd(faithful$waiting)
dp <- DirichletProcessGaussian(faithfulTransformed)
dp <- Fit(dp, 100, progressBar = FALSE)
plot(dp)
data.frame(Weight=dp$weights, Mean=c(dp$clusterParameters[[1]]), SD=c(dp$clusterParameters[[1]]))
#>        Weight       Mean         SD
#> 1 0.371323529 -1.1756510 -1.1756510
#> 2 0.625000000  0.6597522  0.6597522
#> 3 0.003676471  0.1061095  0.1061095

Clustering

Dirichlet processes can also be used to cluster data based on their common distribution parameters.

faithfulTrans <- as.matrix(apply(faithful, 2, function(x) (x-mean(x))/sd(x)))
dpCluster <-  DirichletProcessMvnormal(faithfulTrans)
dpCluster <- Fit(dpCluster, 1000, progressBar = FALSE)

To plot the results we take the cluster labels contained in the dp object and assign them a colour

For more detailed explanations and examples see the vignette.