igCom</code> and is used in the
paper of Qi and Luo (2019). The authors propose a function-on-function
regression model of the <code>NO2</code> functional variable on all the
other functional variables available in the dataset. In order to show
how the package works, we consider a scalar-on-function regression
model, where we take the mean of <code>NO2</code> at each observation as
the scalar response and all other functions as functional
covariates.</p>
<p>First of all, starting from the discrete data, let