function(initial.level = 0.3, start.change = 10, stop.change = 20)
{
#Program compute.theta.time.trend()
#
#Computes a vector of levels used in setting the values in theta.f or theta.m
#
	part1 <- rep(initial.level, times = start.change)
	slope <- initial.level/(stop.change - start.change)
	part2 <- initial.level - slope * 1:(stop.change - start.change)
	part3 <- rep(0, times = max(tt, stop.change) - stop.change)
	theta.time.trend <- c(part1, part2, part3)
	theta.time.trend <- theta.time.trend[1:tt]
	write.ascii(compute.theta.time.trend)
	theta.time.trend
}