% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/callbacks.R
\name{cb.reset.parameters}
\alias{cb.reset.parameters}
\title{Callback closure for resetting the booster's parameters at each iteration.}
\usage{
cb.reset.parameters(new_params)
}
\arguments{
\item{new_params}{a list where each element corresponds to a parameter that needs to be reset.
Each element's value must be either a vector of values of length \code{nrounds}
to be set at each iteration,
or a function of two parameters \code{learning_rates(iteration, nrounds)}
which returns a new parameter value by using the current iteration number
and the total number of boosting rounds.}
}
\description{
Callback closure for resetting the booster's parameters at each iteration.
}
\details{
This is a "pre-iteration" callback function used to reset booster's parameters
at the beginning of each iteration.

Note that when training is resumed from some previous model, and a function is used to
reset a parameter value, the \code{nrounds} argument in this function would be the
the number of boosting rounds in the current training.

Callback function expects the following values to be set in its calling frame:
\code{bst} or \code{bst_folds},
\code{iteration},
\code{begin_iteration},
\code{end_iteration}.
}
\seealso{
\code{\link{callbacks}}
}