, N8 H: K( [+ [$ x/ }( l+ Q% GM(1,1) si short for gray model % W" h1 a# _) I! q6 Q% t is short for time; ' c1 c" W6 ?# l) z# w, ~% E is short for contrary error * W# I* L5 t# y9 j3 m9 _% @; y% e is short for absolute error ; S0 V. U" y# G& d% [q,e,E]=gm(Q,t) - K) j% v1 U) A/ h4 V' l C+ |4 G9 v% {& q+ Q! N
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