[R] RE : Creating functions with a loop.

[Etienne Larrivée-Hardy]

I must say I'm new here and I don't quite know how things work so you will have to excuse me.

The first part of my problem is that it would help me greatly to have a loop creating all the functions.  Here is an example of how the 10th function would need to look like:

ff10 <- function (q, alph, lam) 
{
    ff9(q, alph, lam) - sum(v.pp[1:(10 - 1)] * exp(-v.beta[1:(10 - 1)] * cc1 * 10^(1:(10 - 1) - 1)))
}

where v.pp and v.beta are vector for which values are known up to 9 in this case. cc1, bb, alpha, lambda are fixed.

The second part of my problem is that with those functions I need to calculate the next value of v.beta and v.pp. 

v.beta[10] <- 1/((bb-1)*cc1*10^-(10-1))*log(ff2(cc1*10^-(10-1),alpha,lambda)/ff10(cc1*10^-(10-1)*bb,alpha,lambda))
and 
v.pp[10] <- ...

I don't know if that made it any clearer...
________________________________________
De : David Winsemius [dwinsemius at comcast.net]
Date d'envoi : 22 mai 2012 11:08
À : Etienne Larrivée-Hardy
Cc : r-help at r-project.org
Objet : Re: [R] Creating functions with a loop.

On May 22, 2012, at 10:06 AM, Etienne Larrivée-Hardy wrote:

> Hi
>
> I am trying to create n functions where each function is defined in
> function one step before, i.e. something like
>
> ff.k(x) = ff.j(x) - sum(1:j),      for j=k-1

There is a cumsum function:

 > cumsum(1:10)
  [1]  1  3  6 10 15 21 28 36 45 55

Did you mean something like?:

  ff.k[j] <- ff.j[j] - sum(1:j),      for j=k-1

In R the paren, "(", indicates that you are calling a function whereas
you appear interested in making an indexed assignment to a vector.

>
> Is it possible? If it isn't and I manually create each function then
> is their a way to call them through a loop?  My objective is to
> calculate something like
>
> result.k = ff.k(x1)/ff.k(x2)      for k in 2:n

You may have clear idea about which k-indices should go where in that
expression, but I surely do not. What are 'x1' and 'x2'?

--

David Winsemius, MD
West Hartford, CT