63 lines
2.0 KiB
R
63 lines
2.0 KiB
R
% Generated by roxygen2: do not edit by hand
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% Please edit documentation in R/xgb.Booster.R
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\name{xgb.is.same.Booster}
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\alias{xgb.is.same.Booster}
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\title{Check if two boosters share the same C object}
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\usage{
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xgb.is.same.Booster(obj1, obj2)
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}
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\arguments{
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\item{obj1}{Booster model to compare with \code{obj2}.}
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\item{obj2}{Booster model to compare with \code{obj1}.}
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}
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\value{
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Either \code{TRUE} or \code{FALSE} according to whether the two boosters share the
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underlying C object.
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}
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\description{
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Checks whether two booster objects refer to the same underlying C object.
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}
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\details{
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As booster objects (as returned by e.g. \code{\link[=xgb.train]{xgb.train()}}) contain an R 'externalptr'
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object, they don't follow typical copy-on-write semantics of other R objects - that is, if
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one assigns a booster to a different variable and modifies that new variable through in-place
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methods like \code{\link[=xgb.attr<-]{xgb.attr<-()}}, the modification will be applied to both the old and the new
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variable, unlike typical R assignments which would only modify the latter.
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This function allows checking whether two booster objects share the same 'externalptr',
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regardless of the R attributes that they might have.
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In order to duplicate a booster in such a way that the copy wouldn't share the same
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'externalptr', one can use function \code{\link[=xgb.copy.Booster]{xgb.copy.Booster()}}.
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}
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\examples{
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library(xgboost)
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data(mtcars)
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y <- mtcars$mpg
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x <- as.matrix(mtcars[, -1])
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model <- xgb.train(
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params = list(nthread = 1),
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data = xgb.DMatrix(x, label = y, nthread = 1),
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nround = 3
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)
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model_shallow_copy <- model
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xgb.is.same.Booster(model, model_shallow_copy) # same C object
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model_deep_copy <- xgb.copy.Booster(model)
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xgb.is.same.Booster(model, model_deep_copy) # different C objects
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# In-place assignments modify all references,
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# but not full/deep copies of the booster
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xgb.attr(model_shallow_copy, "my_attr") <- 111
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xgb.attr(model, "my_attr") # gets modified
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xgb.attr(model_deep_copy, "my_attr") # doesn't get modified
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}
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\seealso{
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\code{\link[=xgb.copy.Booster]{xgb.copy.Booster()}}
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}
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