| % File src/library/stats/man/nls.control.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2020 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{nls.control} |
| \alias{nls.control} |
| \title{Control the Iterations in nls} |
| \description{ |
| Allow the user to set some characteristics of the \code{\link{nls}} |
| nonlinear least squares algorithm. |
| } |
| \usage{ |
| nls.control(maxiter = 50, tol = 1e-05, minFactor = 1/1024, |
| printEval = FALSE, warnOnly = FALSE, scaleOffset = 0, |
| nDcentral = FALSE) |
| } |
| \arguments{ |
| \item{maxiter}{A positive integer specifying the maximum number of |
| iterations allowed.} |
| \item{tol}{A positive numeric value specifying the tolerance level for |
| the relative offset convergence criterion.} |
| \item{minFactor}{A positive numeric value specifying the minimum |
| step-size factor allowed on any step in the iteration. The |
| increment is calculated with a Gauss-Newton algorithm and |
| successively halved until the residual sum of squares has been |
| decreased or until the step-size factor has been reduced below this |
| limit.} |
| \item{printEval}{a logical specifying whether the number of evaluations |
| (steps in the gradient direction taken each iteration) is printed.} |
| \item{warnOnly}{a logical specifying whether \code{\link{nls}()} should |
| return instead of signalling an error in the case of termination |
| before convergence. |
| Termination before convergence happens upon completion of \code{maxiter} |
| iterations, in the case of a singular gradient, and in the case that the |
| step-size factor is reduced below \code{minFactor}.} |
| \item{scaleOffset}{a constant to be added to the denominator of the relative |
| offset convergence criterion calculation to avoid a zero divide in the case |
| where the fit of a model to data is very close. The default value of |
| \code{0} keeps the legacy behaviour of \code{nls()}. A value such as |
| \code{1} seems to work for problems of reasonable scale with very small |
| residuals.} |
| \item{nDcentral}{only when \emph{numerical} derivatives are used: |
| \code{\link{logical}} indicating if \emph{central} differences |
| should be employed, i.e., \code{\link{numericDeriv}(*, central=TRUE)} |
| be used.} |
| } |
| \value{ |
| A \code{\link{list}} with components |
| \item{maxiter}{} |
| \item{tol}{} |
| \item{minFactor}{} |
| \item{printEval}{} |
| \item{warnOnly}{} |
| \item{scaleOffset}{} |
| \item{nDcentreal}{} |
| with meanings as explained under \sQuote{Arguments}. |
| } |
| \references{ |
| Bates, D. M. and Watts, D. G. (1988), |
| \emph{Nonlinear Regression Analysis and Its Applications}, Wiley. |
| } |
| \author{Douglas Bates and Saikat DebRoy; John C. Nash for part of the |
| \code{scaleOffset} option.} |
| \seealso{ |
| \code{\link{nls}} |
| } |
| \examples{ |
| nls.control(minFactor = 1/2048) |
| } |
| \keyword{nonlinear} |
| \keyword{regression} |
| \keyword{models} |