constantGrowthSeries: Constant Growth Series

Description

Create tis time series that grow at constant rates.

fanSeries(startValue, start, end, rates)
tunnelSeries(startValue, start, end, rate, spreads)

startValue

starting value for the series at time start

start

a ti (Time Index) for the first observation.

end

a ti or something that can be turned into a ti giving the time index for the last observation.

rates

annual growth rate(s) for the series to be created

rate

annual growth rate for the series to be created

spreads

vector of 2 numbers giving the percentage values by which the starting values of the 'tunnel' series should be offset from startValue

fanSeries returns a multivariate series that starts on start and ends on end. There are length(rates) columns. Each column begins at startValue and grows at the rate given by its corresponding element in rates. These are not true growth rates, rather each column has a constant first difference such that over the course of the first year, column i will grow rates[i] percent. This yields series that plot as straight lines.
tunnelSeries first calls fanSeries to create a univariate series running from start to end with a starting value of startValue and growing rate percent over the first year. It returns a bivariate series with columns that are offset from that series by spreads[1] and spreads[2] percent of the startValue.