.Internal

I was trying to find source for optimize and I ran across

function (f, interval, ..., lower = min(interval), upper =
max(interval), maximum = FALSE, tol = .Machine$double.eps^0.25) 
{
    if (maximum) {
        val <- .Internal(fmin(function(arg) -f(arg, ...), lower, 
            upper, tol))
        list(maximum = val, objective = f(val, ...))
    }
    else {
        val <- .Internal(fmin(function(arg) f(arg, ...), lower, 
            upper, tol))
        list(minimum = val, objective = f(val, ...))
    }
}

Then I did a search for fmin and i came up with:

/* fmin(f, xmin, xmax tol) */
SEXP attribute_hidden do_fmin(SEXP call, SEXP op, SEXP args, SEXP rho)


So my question is where do I find the intermediary step between 

.Internal(fmin(function(arg) f(arg, ...), lower,  upper, tol))

and

SEXP attribute_hidden do_fmin(SEXP call, SEXP op, SEXP args, SEXP rho)

The number of arguments doesn't match up. I am guessing that lower
and upper somehow get merged into the args. And rho is 'tol'. Right?

G'day Kevin,

On Wed, 18 Mar 2009 21:46:51 -0700
<rkevinburton at charter.net> wrote:

I was trying to find source for optimize and I ran across

function (f, interval, ..., lower = min(interval), upper =
max(interval), maximum = FALSE, tol = .Machine$double.eps^0.25) 
{
    if (maximum) {
        val <- .Internal(fmin(function(arg) -f(arg, ...), lower, 
            upper, tol))
        list(maximum = val, objective = f(val, ...))
    }
    else {
        val <- .Internal(fmin(function(arg) f(arg, ...), lower, 
            upper, tol))
        list(minimum = val, objective = f(val, ...))
    }
}

Then I did a search for fmin and i came up with:

/* fmin(f, xmin, xmax tol) */
SEXP attribute_hidden do_fmin(SEXP call, SEXP op, SEXP args, SEXP rho)


So my question is where do I find the intermediary step between 

.Internal(fmin(function(arg) f(arg, ...), lower,  upper, tol))

and

SEXP attribute_hidden do_fmin(SEXP call, SEXP op, SEXP args, SEXP rho)

@Article{Rnews:Ligges:2006,
  author       = {Uwe Ligges},
  title        = {{R} {H}elp {D}esk: {Accessing} the Sources},
  journal      = {R News},
  year         = 2006,
  volume       = 6,
  number       = 4,
  pages        = {43--45},
  month        = {October},
  url          = http,
  pdf	       = Rnews2006-4
}

http://CRAN.R-project.org/doc/Rnews/Rnews_2006-4.pdf

The number of arguments doesn't match up. I am guessing that lower
and upper somehow get merged into the args. And rho is 'tol'. Right?

Unlikely.  In "Writing R Extensions" (and the functions I looked up),
'rho' usually denotes an environment that is used to evaluate
expressions in.  Typically (i.e. in cases that I had need to look at),
all arguments are rolled into the SEXP arg for internal functions.

HTH.

Cheers,

	Berwin

Sorry to be so dense but the article that you suggest does not give
any information on how the arguments are packed up. I look at the
call:

val <- .Internal(fmin(function(arg) -f(arg, ...), lower, upper, tol))

and then with the help of this article I find do_fmin in optimize.c:

SEXP attribute_hidden do_fmin(SEXP call, SEXP op, SEXP args, SEXP rho)

Again there doesn't seem to be any coorespondance between lower,
upper, tol and the arguments to do_fmin. So I am missing a step.