Grocer Function
NAME
extrap - extrapolate a ts by another ts
CALLING SEQUENCE
tsout=extrap(arg1,...argn)
PARAMETERS
Input
Output
DESCRIPTION
Extrapolates the first time series by the growth rate of the following ones over the future of each preceding time series. Can probably be made more efficient.
EXAMPLE
if x is a ts defined over the time span '10a'-'20a', y a ts defined over the time span '19a-28a' and z a ts defined over the time span '1a'-'35a':
1) a = overlay(x,y)
2) b= overlay(x,y,z)
3) c= overaly(x,z)
a is a ts defined over the time span '10a'-'28a', equal to x over the time span '10a'-'20a', y*value(x/y,'20a') over the time span '21a'-'28a'.
b is a ts defined over the time span '10a'-'35a', equal to x over the time span '10a'-'35a', y*value(x/y,'20a') over the time span '21a'-'28a', z*value(y/z,'25a')* value(x/y,'20a') over the time span '29a'-'35a'.
c is a ts defined over the time span '10a'-'35a', equal to x over the time span '10a'-'20a', y*value(x/y,'20a') over the time span '21a'-'35a'.
AUTHOR
Eric Dubois 2002