R help - Sep 2007 - certain number of equations in function depending on parameter

Hello everybody, 

i have the following problem to write a function which recognizes depending
on the parameter-inputs how many equations for the calculation in the function
are needed. 

Here is an example of my problem:

"myfun" <- function(a, b, c, d)
{
    k <- length(a)
    #here d = 3 for example, but how can i dynamically controll 
    #my function and tell her to build equations eq1 to eq5 if d = 5?
    
    "eq1" <- function(a, b, y)
    {
        c[k-1] <- a[k-1] + b * y
    } 
    
    "eq2" <- function(a, b, y)
    {
        c[k-2] <- a[k-2] + b * y
    }     
    
    "eq3" <- function(a, b, y)
    {
        c[k-3] <- a[k-3] + b * y
    } 
    
    "eq4" <- function(a, b, z)
    {
        1 - sum(c(eq1(z), eq2(z), eq3(z), z))
    }   
    
    sol <- uniroot(eq4, lower=0, upper=1)
}

I hope my problems is explained clear enough. I would be very happy 
if you can give me some advice.


best regards

Andreas
--

Hi Andreas,

One possible way would be to create a file containing
all your equations (which are written in a loop), then
source that file and then use uniroot.

Regards,

Moshe.

--- Andreas  Wittmann <andreas_wittmann at gmx.de> wrote:
> Hello everybody, 
> 
> i have the following problem to write a function
> which recognizes depending
> on the parameter-inputs how many equations for the
> calculation in the function
> are needed. 
> 
> Here is an example of my problem:
> 
> "myfun" <- function(a, b, c, d)
> {
>     k <- length(a)
>     #here d = 3 for example, but how can i
> dynamically controll 
>     #my function and tell her to build equations eq1
> to eq5 if d = 5?
>     
>     "eq1" <- function(a, b, y)
>     {
>         c[k-1] <- a[k-1] + b * y
>     } 
>     
>     "eq2" <- function(a, b, y)
>     {
>         c[k-2] <- a[k-2] + b * y
>     }     
>     
>     "eq3" <- function(a, b, y)
>     {
>         c[k-3] <- a[k-3] + b * y
>     } 
>     
>     "eq4" <- function(a, b, z)
>     {
>         1 - sum(c(eq1(z), eq2(z), eq3(z), z))
>     }   
>     
>     sol <- uniroot(eq4, lower=0, upper=1)
> }
> 
> I hope my problems is explained clear enough. I
> would be very happy 
> if you can give me some advice.
> 
> 
> best regards
> 
> Andreas
> --
> 
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