npregfast is an R package for obtain nonparametric estimates of regression models with or without factor-by-curve interactions using local polynomial kernel smoothers or splines. Additionally, a parametric model (allometric model) can be estimated. Particular features of the package are facilities for fast smoothness estimation, and the calculation of their first and second derivative. Users can define the smoothers parameters. Confidence intervals calculation is provided by bootstrap methods. Binning techniques were applied to speed up computation in the estimation and testing processes.

You can view a live interactive demo to see part of its capabilities at http://sestelo.shinyapps.io/npregfast.

npregfast is available through both CRAN and GitHub.

Get the released version from CRAN:

install.packages("npregfast")

Or the development version from GitHub:

# install.packages("devtools")
devtools::install_github("sestelo/npregfast")