ml.dmlc.xgboost4j.java

## Class DMatrix

- java.lang.Object
- - ml.dmlc.xgboost4j.java.DMatrix

-     public class DMatrix
      extends Object

  DMatrix for xgboost.
  Author:
    hzx

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `DMatrix.SparseType` sparse matrix type (CSR or CSC)

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected long` | `handle`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `` | `DMatrix(BigDenseMatrix matrix)` create DMatrix from a BigDenseMatrix
    `` | `DMatrix(BigDenseMatrix matrix, float missing)` create DMatrix from dense matrix
    `` | `DMatrix(float[] data, int nrow, int ncol)` create DMatrix from dense matrix
    `` | `DMatrix(float[] data, int nrow, int ncol, float missing)` create DMatrix from dense matrix
    `` | `DMatrix(Iterator<LabeledPoint> iter, String cacheInfo)` Create DMatrix from iterator.
    `protected` | `DMatrix(long handle)` used for DMatrix slice
    `` | `DMatrix(long[] headers, int[] indices, float[] data, DMatrix.SparseType st)` Deprecated.
    `` | `DMatrix(long[] headers, int[] indices, float[] data, DMatrix.SparseType st, int shapeParam)` Create DMatrix from Sparse matrix in CSR/CSC format.
    `` | `DMatrix(String dataPath)` Create DMatrix by loading libsvm file from dataPath

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `dispose()`
    `protected void` | `finalize()`
    `float[]` | `getBaseMargin()` Get base margin of the DMatrix.
    `int[]` | `getGroup()` Get group sizes of DMatrix
    `long` | `getHandle()` Get the handle
    `float[]` | `getLabel()` get label values
    `float[]` | `getWeight()` get weight of the DMatrix
    `long` | `rowNum()` get the row number of DMatrix
    `void` | `saveBinary(String filePath)` save DMatrix to filePath
    `void` | `setBaseMargin(float[] baseMargin)` Set base margin (initial prediction).
    `void` | `setBaseMargin(float[][] baseMargin)` Set base margin (initial prediction).
    `void` | `setGroup(int[] group)` Set group sizes of DMatrix (used for ranking)
    `void` | `setLabel(float[] labels)` set label of dmatrix
    `void` | `setWeight(float[] weights)` set weight of each instance
    `DMatrix` | `slice(int[] rowIndex)` Slice the DMatrix and return a new DMatrix that only contains `rowIndex`.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### handle

          protected long handle

  - ### Constructor Detail

    - #### DMatrix

          public DMatrix(Iterator<LabeledPoint> iter,
                         String cacheInfo)
                  throws XGBoostError

      Create DMatrix from iterator.
      Parameters:
        `iter` - The data iterator of mini batch to provide the data.
        `cacheInfo` - Cache path information, used for external memory setting, can be null.
      Throws:
        `XGBoostError`

    - #### DMatrix

          public DMatrix(String dataPath)
                  throws XGBoostError

      Create DMatrix by loading libsvm file from dataPath
      Parameters:
        `dataPath` - The path to the data.
      Throws:
        `XGBoostError`

    - #### DMatrix

          @Deprecated
          public DMatrix(long[] headers,
                                     int[] indices,
                                     float[] data,
                                     DMatrix.SparseType st)
                              throws XGBoostError

      Deprecated.
      Create DMatrix from Sparse matrix in CSR/CSC format.
      Parameters:
        `headers` - The row index of the matrix.
        `indices` - The indices of presenting entries.
        `data` - The data content.
        `st` - Type of sparsity.
      Throws:
        `XGBoostError`

    - #### DMatrix

          public DMatrix(long[] headers,
                         int[] indices,
                         float[] data,
                         DMatrix.SparseType st,
                         int shapeParam)
                  throws XGBoostError

      Create DMatrix from Sparse matrix in CSR/CSC format.
      Parameters:
        `headers` - The row index of the matrix.
        `indices` - The indices of presenting entries.
        `data` - The data content.
        `st` - Type of sparsity.
        `shapeParam` - when st is CSR, it specifies the column number, otherwise it is taken as row number
      Throws:
        `XGBoostError`

    - #### DMatrix

          public DMatrix(float[] data,
                         int nrow,
                         int ncol)
                  throws XGBoostError

      create DMatrix from dense matrix
      Parameters:
        `data` - data values
        `nrow` - number of rows
        `ncol` - number of columns
      Throws:
        `XGBoostError` - native error

    - #### DMatrix

          public DMatrix(BigDenseMatrix matrix)
                  throws XGBoostError

      create DMatrix from a BigDenseMatrix
      Parameters:
        `matrix` - instance of BigDenseMatrix
      Throws:
        `XGBoostError` - native error

    - #### DMatrix

          public DMatrix(float[] data,
                         int nrow,
                         int ncol,
                         float missing)
                  throws XGBoostError

      create DMatrix from dense matrix
      Parameters:
        `data` - data values
        `nrow` - number of rows
        `ncol` - number of columns
        `missing` - the specified value to represent the missing value
      Throws:
        `XGBoostError`

    - #### DMatrix

          public DMatrix(BigDenseMatrix matrix,
                         float missing)
                  throws XGBoostError

      create DMatrix from dense matrix
      Parameters:
        `matrix` - instance of BigDenseMatrix
        `missing` - the specified value to represent the missing value
      Throws:
        `XGBoostError`

    - #### DMatrix

          protected DMatrix(long handle)

      used for DMatrix slice

  - ### Method Detail

    - #### setLabel

          public void setLabel(float[] labels)
                        throws XGBoostError

      set label of dmatrix
      Parameters:
        `labels` - labels
      Throws:
        `XGBoostError` - native error

    - #### setWeight

          public void setWeight(float[] weights)
                         throws XGBoostError

      set weight of each instance
      Parameters:
        `weights` - weights
      Throws:
        `XGBoostError` - native error

    - #### setBaseMargin

          public void setBaseMargin(float[] baseMargin)
                             throws XGBoostError

      Set base margin (initial prediction). The margin must have the same number of elements as the number of rows in this matrix.
      Throws:
        `XGBoostError`

    - #### setBaseMargin

          public void setBaseMargin(float[][] baseMargin)
                             throws XGBoostError

      Set base margin (initial prediction).
      Throws:
        `XGBoostError`

    - #### setGroup

          public void setGroup(int[] group)
                        throws XGBoostError

      Set group sizes of DMatrix (used for ranking)
      Parameters:
        `group` - group size as array
      Throws:
        `XGBoostError` - native error

    - #### getGroup

          public int[] getGroup()
                         throws XGBoostError

      Get group sizes of DMatrix
      Returns:
        group size as array
      Throws:
        `XGBoostError` - native error

    - #### getLabel

          public float[] getLabel()
                           throws XGBoostError

      get label values
      Returns:
        label
      Throws:
        `XGBoostError` - native error

    - #### getWeight

          public float[] getWeight()
                            throws XGBoostError

      get weight of the DMatrix
      Returns:
        weights
      Throws:
        `XGBoostError` - native error

    - #### getBaseMargin

          public float[] getBaseMargin()
                                throws XGBoostError

      Get base margin of the DMatrix.
      Throws:
        `XGBoostError`

    - #### slice

          public DMatrix slice(int[] rowIndex)
                        throws XGBoostError

      Slice the DMatrix and return a new DMatrix that only contains `rowIndex`.
      Parameters:
        `rowIndex` - row index
      Returns:
        sliced new DMatrix
      Throws:
        `XGBoostError` - native error

    - #### rowNum

          public long rowNum()
                      throws XGBoostError

      get the row number of DMatrix
      Returns:
        number of rows
      Throws:
        `XGBoostError` - native error

    - #### saveBinary

          public void saveBinary(String filePath)

      save DMatrix to filePath

    - #### getHandle

          public long getHandle()

      Get the handle

    - #### finalize

          protected void finalize()

      Overrides:
        `finalize` in class `Object`

    - #### dispose

          public void dispose()

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