data("demoLGCM")
data("trueParas")
lgcm <- gppm(
  "muI+muS*t", "varI+covIS*(t+t#)+varS*t*t#+(t==t#)*sigma",
  demoLGCM, "ID", "y"
)
parameterValues <- trueParas
mlValues <- c(57.86418519, -0.96213162, 4.42108943, 0.22716305, 0.95216303, 0.01003411)
names(mlValues) <- c("muI", "muS", "varI", "covIS", "varS", "sigma")
lgcmFit <- fit(lgcm, init = mlValues, verbose = TRUE)
modelForExtract <- lgcmFit