Implements variable screening techniques for ultra-high
dimensional regression settings. Techniques for independent (iid) data,
varying-coefficient models, and longitudinal data are implemented. The package
currently contains three screen functions: screenIID(), screenLD() and screenVCM(),
and six methods for simulating dataset: simulateDCSIS(), simulateLD, simulateMVSIS(),
simulateMVSISNY(), simulateSIRS() and simulateVCM(). The package is based on the work of
Li-Ping ZHU, Lexin LI, Runze LI, and Li-Xing ZHU (2011)