[R] docs update - callbacks and parameter style

R-package/man/cb.print.evaluation.Rd

@@ -0,0 +1,28 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/callbacks.R
+\name{cb.print.evaluation}
+\alias{cb.print.evaluation}
+\title{Callback closure for printing the result of evaluation}
+\usage{
+cb.print.evaluation(period = 1)
+}
+\arguments{
+\item{period}{results would be printed every number of periods}
+}
+\description{
+Callback closure for printing the result of evaluation
+}
+\details{
+The callback function prints the result of evaluation at every \code{period} iterations.
+The initial and the last iteration's evaluations are always printed.
+
+Callback function expects the following values to be set in its calling frame:
+\code{bst_evaluation} (also \code{bst_evaluation_err} when available),
+\code{iteration},
+\code{begin_iteration},
+\code{end_iteration}.
+}
+\seealso{
+\code{\link{callbacks}}
+}
+