66 lines
3.0 KiB
R
66 lines
3.0 KiB
R
% Generated by roxygen2: do not edit by hand
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% Please edit documentation in R/xgb.DMatrix.R
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\name{xgb.QuantileDMatrix.from_iterator}
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\alias{xgb.QuantileDMatrix.from_iterator}
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\title{QuantileDMatrix from External Data}
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\usage{
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xgb.QuantileDMatrix.from_iterator(
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data_iterator,
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missing = NA,
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nthread = NULL,
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ref = NULL,
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max_bin = NULL
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)
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}
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\arguments{
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\item{data_iterator}{A data iterator structure as returned by \link{xgb.DataIter},
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which includes an environment shared between function calls, and functions to access
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the data in batches on-demand.}
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\item{missing}{A float value to represents missing values in data.
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Note that, while functions like \link{xgb.DMatrix} can take a generic \code{NA} and interpret it
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correctly for different types like \code{numeric} and \code{integer}, if an \code{NA} value is passed here,
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it will not be adapted for different input types.
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For example, in R \code{integer} types, missing values are represented by integer number \code{-2147483648}
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(since machine 'integer' types do not have an inherent 'NA' value) - hence, if one passes \code{NA},
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which is interpreted as a floating-point NaN by 'xgb.ExternalDMatrix' and by
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'xgb.QuantileDMatrix.from_iterator', these integer missing values will not be treated as missing.
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This should not pose any problem for \code{numeric} types, since they do have an inheret NaN value.}
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\item{nthread}{Number of threads used for creating DMatrix.}
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\item{ref}{The training dataset that provides quantile information, needed when creating
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validation/test dataset with \code{xgb.QuantileDMatrix}. Supplying the training DMatrix
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as a reference means that the same quantisation applied to the training data is
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applied to the validation/test data}
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\item{max_bin}{The number of histogram bin, should be consistent with the training parameter
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\code{max_bin}.
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This is only supported when constructing a QuantileDMatrix.}
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}
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\value{
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An 'xgb.DMatrix' object, with subclass 'xgb.QuantileDMatrix'.
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}
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\description{
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Create an \code{xgb.QuantileDMatrix} object (exact same class as would be returned by
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calling function \link{xgb.QuantileDMatrix}, with the same advantages and limitations) from
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external data supplied by an \link{xgb.DataIter} object, potentially passed in batches from
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a bigger set that might not fit entirely in memory, same way as \link{xgb.ExternalDMatrix}.
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Note that, while external data will only be loaded through the iterator (thus the full data
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might not be held entirely in-memory), the quantized representation of the data will get
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created in-memory, being concatenated from multiple calls to the data iterator. The quantized
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version is typically lighter than the original data, so there might be cases in which this
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representation could potentially fit in memory even if the full data doesn't.
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For more information, see the guide 'Using XGBoost External Memory Version':
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\url{https://xgboost.readthedocs.io/en/stable/tutorials/external_memory.html}
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}
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\seealso{
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\link{xgb.DataIter}, \link{xgb.DataBatch}, \link{xgb.ExternalDMatrix},
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\link{xgb.QuantileDMatrix}
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}
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