gamm4.test is a package supplied with R for testing nonlinear curve and surface functions.The main testing routine is gam.test.
The major advantages of this packages are:
Arguements formulated are consistent with semiparametric regression estimating package “mgcv” and “gamm4”, so that people who are familiar with these ones can easily adopt our major function gam.grptest().
We allow parallel computing by specifying parallel = TRUE within function gam.grptest to save computational time if needed.
plot.gamtest() function plots semiparametric estimated nonlinear curves and surfaces via R package “plotly”. Option type=plotly.persp provides a 3-D interactive plot with estimated regression functions for individual groups. Also, test.statistic = TRUE provides the empirical distribution of the test statistic under the null hypothesis of equal regression function.