Class SelectedDenseDoubleMatrix2D

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable

    class SelectedDenseDoubleMatrix2D
    extends DoubleMatrix2D
    Selection view on dense 2-d matrices holding double elements. First see the package summary and javadoc tree view to get the broad picture.

    Implementation:

    Objects of this class are typically constructed via viewIndexes methods on some source matrix. The interface introduced in abstract super classes defines everything a user can do. From a user point of view there is nothing special about this class; it presents the same functionality with the same signatures and semantics as its abstract superclass(es) while introducing no additional functionality. Thus, this class need not be visible to users. By the way, the same principle applies to concrete DenseXXX and SparseXXX classes: they presents the same functionality with the same signatures and semantics as abstract superclass(es) while introducing no additional functionality. Thus, they need not be visible to users, either. Factory methods could hide all these concrete types.

    This class uses no delegation. Its instances point directly to the data. Cell addressing overhead is 1 additional int addition and 2 additional array index accesses per get/set.

    Note that this implementation is not synchronized.

    Memory requirements:

    memory [bytes] = 4*(rowIndexes.length+columnIndexes.length). Thus, an index view with 1000 x 1000 indexes additionally uses 8 KB.

    Time complexity:

    Depends on the parent view holding cells.

    Version:
    1.0, 09/24/99
    • Field Detail

      • elements

        protected double[] elements
        The elements of this matrix.
      • rowOffsets

        protected int[] rowOffsets
        The offsets of the visible cells of this matrix.
      • columnOffsets

        protected int[] columnOffsets
      • offset

        protected int offset
        The offset.
    • Constructor Detail

      • SelectedDenseDoubleMatrix2D

        protected SelectedDenseDoubleMatrix2D​(double[] elements,
                                              int[] rowOffsets,
                                              int[] columnOffsets,
                                              int offset)
        Constructs a matrix view with the given parameters.
        Parameters:
        elements - the cells.
        rowOffsets - The row offsets of the cells that shall be visible.
        columnOffsets - The column offsets of the cells that shall be visible.
        offset -
      • SelectedDenseDoubleMatrix2D

        protected SelectedDenseDoubleMatrix2D​(int rows,
                                              int columns,
                                              double[] elements,
                                              int rowZero,
                                              int columnZero,
                                              int rowStride,
                                              int columnStride,
                                              int[] rowOffsets,
                                              int[] columnOffsets,
                                              int offset)
        Constructs a matrix view with the given parameters.
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        elements - the cells.
        rowZero - the position of the first element.
        columnZero - the position of the first element.
        rowStride - the number of elements between two rows, i.e. index(i+1,j)-index(i,j).
        columnStride - the number of elements between two columns, i.e. index(i,j+1)-index(i,j).
        rowOffsets - The row offsets of the cells that shall be visible.
        columnOffsets - The column offsets of the cells that shall be visible.
        offset -
    • Method Detail

      • _columnOffset

        protected int _columnOffset​(int absRank)
        Returns the position of the given absolute rank within the (virtual or non-virtual) internal 1-dimensional array. Default implementation. Override, if necessary.
        Overrides:
        _columnOffset in class AbstractMatrix2D
        Parameters:
        rank - the absolute rank of the element.
        Returns:
        the position.
      • _rowOffset

        protected int _rowOffset​(int absRank)
        Returns the position of the given absolute rank within the (virtual or non-virtual) internal 1-dimensional array. Default implementation. Override, if necessary.
        Overrides:
        _rowOffset in class AbstractMatrix2D
        Parameters:
        rank - the absolute rank of the element.
        Returns:
        the position.
      • getQuick

        public double getQuick​(int row,
                               int column)
        Returns the matrix cell value at coordinate [row,column].

        Provided with invalid parameters this method may return invalid objects without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().

        Specified by:
        getQuick in class DoubleMatrix2D
        Parameters:
        row - the index of the row-coordinate.
        column - the index of the column-coordinate.
        Returns:
        the value at the specified coordinate.
      • haveSharedCellsRaw

        protected boolean haveSharedCellsRaw​(DoubleMatrix2D other)
        Returns true if both matrices share common cells. More formally, returns true if other != null and at least one of the following conditions is met
        • the receiver is a view of the other matrix
        • the other matrix is a view of the receiver
        • this == other
        Overrides:
        haveSharedCellsRaw in class DoubleMatrix2D
      • index

        protected int index​(int row,
                            int column)
        Returns the position of the given coordinate within the (virtual or non-virtual) internal 1-dimensional array.
        Overrides:
        index in class AbstractMatrix2D
        Parameters:
        row - the index of the row-coordinate.
        column - the index of the column-coordinate.
      • like

        public DoubleMatrix2D like​(int rows,
                                   int columns)
        Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of rows and columns. For example, if the receiver is an instance of type DenseDoubleMatrix2D the new matrix must also be of type DenseDoubleMatrix2D, if the receiver is an instance of type SparseDoubleMatrix2D the new matrix must also be of type SparseDoubleMatrix2D, etc. In general, the new matrix should have internal parametrization as similar as possible.
        Specified by:
        like in class DoubleMatrix2D
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        Returns:
        a new empty matrix of the same dynamic type.
      • like1D

        public DoubleMatrix1D like1D​(int size)
        Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver. For example, if the receiver is an instance of type DenseDoubleMatrix2D the new matrix must be of type DenseDoubleMatrix1D, if the receiver is an instance of type SparseDoubleMatrix2D the new matrix must be of type SparseDoubleMatrix1D, etc.
        Specified by:
        like1D in class DoubleMatrix2D
        Parameters:
        size - the number of cells the matrix shall have.
        Returns:
        a new matrix of the corresponding dynamic type.
      • like1D

        protected DoubleMatrix1D like1D​(int size,
                                        int zero,
                                        int stride)
        Construct and returns a new 1-d matrix of the corresponding dynamic type, sharing the same cells. For example, if the receiver is an instance of type DenseDoubleMatrix2D the new matrix must be of type DenseDoubleMatrix1D, if the receiver is an instance of type SparseDoubleMatrix2D the new matrix must be of type SparseDoubleMatrix1D, etc.
        Specified by:
        like1D in class DoubleMatrix2D
        Parameters:
        size - the number of cells the matrix shall have.
        zero - the index of the first element.
        stride - the number of indexes between any two elements, i.e. index(i+1)-index(i).
        Returns:
        a new matrix of the corresponding dynamic type.
      • setQuick

        public void setQuick​(int row,
                             int column,
                             double value)
        Sets the matrix cell at coordinate [row,column] to the specified value.

        Provided with invalid parameters this method may access illegal indexes without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().

        Specified by:
        setQuick in class DoubleMatrix2D
        Parameters:
        row - the index of the row-coordinate.
        column - the index of the column-coordinate.
        value - the value to be filled into the specified cell.
      • setUp

        protected void setUp​(int rows,
                             int columns)
        Sets up a matrix with a given number of rows and columns.
        Overrides:
        setUp in class AbstractMatrix2D
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        Throws:
        java.lang.IllegalArgumentException - if (double)columns*rows > Integer.MAX_VALUE.
      • viewColumn

        public DoubleMatrix1D viewColumn​(int column)
        Constructs and returns a new slice view representing the rows of the given column. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. To obtain a slice view on subranges, construct a sub-ranging view (viewPart(...)), then apply this method to the sub-range view.

        Example:

        2 x 3 matrix:
        1, 2, 3
        4, 5, 6
        viewColumn(0) ==> Matrix1D of size 2:
        1, 4
        Overrides:
        viewColumn in class DoubleMatrix2D
        Parameters:
        the - column to fix.
        Returns:
        a new slice view.
        Throws:
        java.lang.IllegalArgumentException - if column < 0 || column >= columns().
        See Also:
        viewRow(int)
      • viewRow

        public DoubleMatrix1D viewRow​(int row)
        Constructs and returns a new slice view representing the columns of the given row. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. To obtain a slice view on subranges, construct a sub-ranging view (viewPart(...)), then apply this method to the sub-range view.

        Example:

        2 x 3 matrix:
        1, 2, 3
        4, 5, 6
        viewRow(0) ==> Matrix1D of size 3:
        1, 2, 3
        Overrides:
        viewRow in class DoubleMatrix2D
        Parameters:
        the - row to fix.
        Returns:
        a new slice view.
        Throws:
        java.lang.IndexOutOfBoundsException - if row < 0 || row >= rows().
        See Also:
        viewColumn(int)
      • viewSelectionLike

        protected DoubleMatrix2D viewSelectionLike​(int[] rowOffsets,
                                                   int[] columnOffsets)
        Construct and returns a new selection view.
        Specified by:
        viewSelectionLike in class DoubleMatrix2D
        Parameters:
        rowOffsets - the offsets of the visible elements.
        columnOffsets - the offsets of the visible elements.
        Returns:
        a new view.