polywog is an R package by Brenton Kenkel and Curtis Signorino containing routines for flexible functional form estimation via basis regression with oracle-penalized model selection. You can install the most recent stable version of the package from CRAN by running

install.packages("polywog")

in an R console.

To request a feature or report a bug, please visit the package's project page on Github. The package's change log can also be viewed there.