Dear list,

I spent a lot of time looking for the solution for this problem, but with no
success. It's the first time I came to the list to ask for help, so I'm
sorry if I break some protocol.

Well, I'm trying to make a serie of regressions in different periods,
actually, in growing periods. In other words, I start by make a regression
in a period from 1 to t, then I make another regression from 1 to t+1, and
so on until t+1 < N.

A loop version for this is:
a <- rep(1,100)+rnorm(100)
b <- rep(2,100)+rnorm(100)
c <- rep(1.5,100)+rnorm(100)
n.start <- 50
coefs <- array(NA,c(51,4))
for (i in (n.start:100)) coefs[i-n.start+1,] <- coef(lm(a ~ b + c,
subset=1:i))

I want to avoid loops, so I was trying to make something like:

regride <- function(formula,dat,sub,w) {
    window <- c(1:sub)
    w[1:sub-1] <- w[1:sub-1]*beta^sub
    coefs(lm(formula=formula,data=dat,subset=window,weights=w))
}

coefs <- sapply(n_start:dim(ind)[1],regride,formula,dat,x)

But it's not working.

Best regards,
Caio Casimiro

-- 
Caio Ramos Casimiro
Software Developer
+55 11 9773 2809

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