Time series entropy measurement

Novel feature models; circled entropy measurement (CEM) that calculates data
fall over circled pieced regions, squared entropy measurement (SEM) that calculates data fall over squared pieced regions, inclined entropy measurement (IEM) that calculates
data fall over inclined pieced regions, grid entropy measurement (GEM) that calculates data fall over grid pieced regions in secon-order difference plot (SODP) were introduced.

entropyM main function. applies several entropy measurements
nodp function performs difference plot operation throught given vector X
normD lnear normalization

please gently cite
https://arxiv.org/abs/1907.05888
"Regularized HessELM and Inclined Entropy Measurement for Congestive Heart Failure Prediction", 2019