HI R Gurus,

> This is my first foray into using c-code with R, so ...
> I had a look at the archives and did not find anything on this, so
> hopefully I am not doubling up.
> 
I have previously used the following approach where I needed some very
small numbers/large (using Brobdingnag):


surfacewithdiff <- function(t, y, p)
  {
    const=p["const"]
    kay =p["kay"]
    psii=p["psii"]
    m1=p["m1"]
    m2=p["m2"]
    M=p["M"]
    N=p["N"]
    T=p["T"]

    bexp<-as.brob((const*(psii-m1*y[1]-m2*M/N))/T)
    yd1<-as.numeric((kay*exp(bexp))/(kay*t*exp(bexp)+1)-
    	(kay^2*t*exp(2*bexp))/(kay*t*exp(bexp)+1)^2)
    	
    list(c(yd1))
  }


Now I guess this could be done with gmp.

Now I use this stuff in the function that odesolve's lsoda refers to,
and 
I have found that my approach using pure R code is not fast enough, so I
need to convert 
my function to C code. This is all on a windows system.

Is it possible to access gmp or Brobdingnag dll's from the C code?
Or do I need to install and compile the gmp library itself?

> Advice appreciated.
> 
> Kind regards, 
> 
> Matt Redding
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