R help - Oct 2009 - Optim Problem??

I have having the following error message when trying to optimize a function
using optim:


> optim(c(10,100),fn,method="BFGS")
Error in optim(c(10, 100), fn, method = "BFGS") :
  cannot coerce type 'S4' to vector of type
'double'
>
Can someone tell me what this means?

Jim

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On 03/10/2009 5:26 PM, Jim Silverton wrote:
> I have having the following error message when trying to optimize a
function
> using optim:
> 
> 
> 
>> optim(c(10,100),fn,method="BFGS")
> Error in optim(c(10, 100), fn, method = "BFGS") :
>   cannot coerce type 'S4' to vector of type 'double'
> 
> Can someone tell me what this means?
I'd guess your fn doesn't return a numeric vector, it returns an object 
of type 'S4'.  To be more specific, we'd need to see some code to 
reproduce the error message.

Duncan Murdoch