This function checks if fCWTr was compiled with AVX instruction set support. AVX instructions need to be supported by the users' CPU in order for this to work.
Details
By default, most compiler setups do not make use of AVX to increase portability of the binary. If you are an R user that has a CPU supporting AVX and want to make use of it, you might need to manually enable compiler flags to let R know about it, and install the package from source (so that it gets compiled on your machine).