ey <- rep(0,288)
m <- stsm.model(model = "local-trend", y = ts(seq(288), frequency = 12),
            pars = c("var1" = 1, "var2" = 0.05, "var3" = 0.0005), nopars = NULL)
ss <- char2numeric(m)
p <- datagen.stsm(n = 288, model = list(Z = ss$Z, T = ss$T, H = ss$H, Q = ss$Q), n0 = 20, freq = 12, old.version = T)$data