This function calls the cost function and makes it match neldermead
requirements. It is used in the fminsearch function as the
function element of the neldermead object (see ?neldermead
and ?neldermead.set).
fminsearch.function(x = NULL, index = NULL, fmsfundata = NULL)A single column vector of parameter estimates.
An integer variable set to 2, indicating that only the cost function is to be computed by the algorithm.
An object of class 'optimbase.functionargs' and with
(at least) a fun element, which contains the user-defined cost
function.
Returns a list with the following elements:
The value of the cost function at the current point estimate.
The same index variable.
A list with a single element costargument which
contains fmsfundata.