[R] Unable to pass Object Arguments to UniRoot()

[Bazman76]

Hi there,

I'd like to be able to pass an entire object to uniroot() as one of the
arguments. Unfortunately to recreate my precise error would be rather
involved. So I present a simplified version below:

To create a structured object let the output from the lm() function use this
simple code: 

    year <- c(2000 ,   2001  ,  2002  ,  2003 ,   2004)
    rate <- c(9.34 ,   8.50  ,  7.62  ,  6.93  ,  6.60)
    fit <- lm(rate ~ year)


    When I try to pass this to uniroot:

    OptLam<-uniroot(f=LamOpt, interval=c(0.0001,120),
tol=0.0000000000000001, MLEObj=fit )

I get the following error

Error in f(lower, ...) : 
  unused argument(s) (MLEObj = list(coefficients = c(1419.2079999999,
-0.704999999999952), residuals =

This seems to be specific to uniroot I have tested my own functions and they
happily accept objects like fit. The function LamOpt is not supposed to work
with a object created by lm() I've just used lm() as a simple example so
don't worry about the results that LamOpt produces, if I can pass one object
like fit to uniroot then I assume I can pass any object.

It seems that uniroot must be expecting an object of a certain size, would
it therefore be possible to use something analogous to pointers in c/c++ and
pass the object by reference so only a pointer to the object is passed
rather than the object itself?



    LamOpt<-function(lambda,MLEobj){

    x <- c(3,6,9,12,15,18,21,24,30,36,48,60,72,84,96,108,120)

    #MLEObj<-kemfit
    ## Cross-sectional model (Nelson and Siegel)
    #lambda <- 0.0609
    h2 <- function(x){(1-exp(-lambda*x))/(lambda*x)}
    h3 <- function(x){((1-exp(-lambda*x))/(lambda*x)) - exp(-lambda*x)}
    X=cbind(rep(1,m), h2(x), h3(x)) #obs

    Z <- matrix(as.list(X), ncol = 3)

    MLEObj$par$Z=Z

    kf_iter = MARSSkf(MLEobj)

    return(-kf_iter$logLik)
    }

Thanks

Baz
   




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