# Rvmminu: Variable metric nonlinear function minimization,... In Rvmmin: Variable Metric Nonlinear Function Minimization

## Description

An R implementation of a variable metric method for minimization of unconstrained nonlinear functions.

See the manual Rvmmin.Rd for details.

## Usage

 `1` ``` Rvmminu(par, fn, gr, control = list(), ...) ```

## Arguments

 `par` A numeric vector of starting estimates. `fn` A function that returns the value of the objective at the supplied set of parameters `par` using auxiliary data in .... The first argument of `fn` must be `par`. `gr` A function that returns the gradient of the objective at the supplied set of parameters `par` using auxiliary data in .... The first argument of `fn` must be `par`. This function returns the gradient as a numeric vector. Note that a gradient function MUST be provided. See the manual for `Rvmmin`, which is the usual way `Rvmminu` is called. The user must take responsibility for errors if `Rvmminu` is called directly. `control` An optional list of control settings. See the manual Rvmmin.Rd for details. Some control elements apply only when parameters are bounds constrained and are not used in this function. `...` Further arguments to be passed to `fn`.

## Details

This routine is intended to be called from `Rvmmin`, which will, if necessary, supply a gradient approximation. However, some users will want to avoid the extra overhead, in which case it is important to provide an appropriate and high-accuracy gradient routine.

Functions `fn` must return a numeric value.

## Value

A list with components:

 `par` The best set of parameters found. `value` The value of the objective at the best set of parameters found. `counts` A vector of two integers giving the number of function and gradient evaluations. `convergence` An integer indicating the situation on termination of the function. `0` indicates that the method believes it has succeeded. Other values: `1`indicates that the iteration limit `maxit` had been reached. `20`indicates that the initial set of parameters is inadmissible, that is, that the function cannot be computed or returns an infinite, NULL, or NA value. `21`indicates that an intermediate set of parameters is inadmissible. `message` A description of the situation on termination of the function.

`optim`
 `1` ```####in Rvmmin.Rd #### ```