SparseDoubleMatrix2D
cern.colt.matrix.tdouble.impl

Class SparseDoubleMatrix2D

  • All Implemented Interfaces:
    Serializable, Cloneable


    public class SparseDoubleMatrix2Dextends DoubleMatrix2D
    Sparse hashed 2-d matrix holding double elements. First see the package summary and javadoc tree view to get the broad picture.

    Implementation:

    Note that this implementation is not synchronized. Uses a OpenLongDoubleHashMap, which is a compact and performant hashing technique.

    Memory requirements:

    Cells that

    • are never set to non-zero values do not use any memory.
    • switch from zero to non-zero state do use memory.
    • switch back from non-zero to zero state also do use memory. However, their memory is automatically reclaimed from time to time. It can also manually be reclaimed by calling trimToSize().

    worst case: memory [bytes] = (1/minLoadFactor) * nonZeros * 13.
    best case: memory [bytes] = (1/maxLoadFactor) * nonZeros * 13.
    Where nonZeros = cardinality() is the number of non-zero cells. Thus, a 1000 x 1000 matrix with minLoadFactor=0.25 and maxLoadFactor=0.5 and 1000000 non-zero cells consumes between 25 MB and 50 MB. The same 1000 x 1000 matrix with 1000 non-zero cells consumes between 25 and 50 KB.

    Time complexity:

    This class offers expected time complexity O(1) (i.e. constant time) for the basic operations get, getQuick, set, setQuick and size assuming the hash function disperses the elements properly among the buckets. Otherwise, pathological cases, although highly improbable, can occur, degrading performance to O(N) in the worst case. As such this sparse class is expected to have no worse time complexity than its dense counterpart DenseDoubleMatrix2D. However, constant factors are considerably larger.

    Cells are internally addressed in row-major. Performance sensitive applications can exploit this fact. Setting values in a loop row-by-row is quicker than column-by-column, because fewer hash collisions occur. Thus

     for (int row = 0; row < rows; row++) {     for (int column = 0; column < columns; column++) {         matrix.setQuick(row, column, someValue);     } } 
    is quicker than
     for (int column = 0; column < columns; column++) {     for (int row = 0; row < rows; row++) {         matrix.setQuick(row, column, someValue);     } } 
    See Also:
    cern.colt.map, OpenLongDoubleHashMap, Serialized Form
    • Constructor Detail

      • SparseDoubleMatrix2D

        public SparseDoubleMatrix2D(double[][] values)
        Constructs a matrix with a copy of the given values. values is required to have the form values[row][column] and have exactly the same number of columns in every row.

        The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.

        Parameters:
        values - The values to be filled into the new matrix.
        Throws:
        IllegalArgumentException - if for any 1 <= row < values.length: values[row].length != values[row-1].length .
      • SparseDoubleMatrix2D

        public SparseDoubleMatrix2D(int rows,                    int columns)
        Constructs a matrix with a given number of rows and columns and default memory usage. All entries are initially 0.
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        Throws:
        IllegalArgumentException - if rows<0 || columns<0 || (double)columns*rows > Integer.MAX_VALUE .
      • SparseDoubleMatrix2D

        public SparseDoubleMatrix2D(int rows,                    int columns,                    int initialCapacity,                    double minLoadFactor,                    double maxLoadFactor)
        Constructs a matrix with a given number of rows and columns using memory as specified. All entries are initially 0. For details related to memory usage see OpenLongDoubleHashMap.
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        initialCapacity - the initial capacity of the hash map. If not known, set initialCapacity=0 or small.
        minLoadFactor - the minimum load factor of the hash map.
        maxLoadFactor - the maximum load factor of the hash map.
        Throws:
        IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor) .
        IllegalArgumentException - if rows<0 || columns<0 || (double)columns*rows > Integer.MAX_VALUE .
      • SparseDoubleMatrix2D

        public SparseDoubleMatrix2D(int rows,                    int columns,                    int[] rowIndexes,                    int[] columnIndexes,                    double value)
        Constructs a matrix with a copy of the given indexes and a single value.
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        rowIndexes - row indexes
        columnIndexes - column indexes
        value - numerical value
      • SparseDoubleMatrix2D

        public SparseDoubleMatrix2D(int rows,                    int columns,                    int[] rowIndexes,                    int[] columnIndexes,                    double[] values)
        Constructs a matrix with a copy of the given indexes and values.
        Parameters:
        rows - the number of rows the matrix shall have.
        columns - the number of columns the matrix shall have.
        rowIndexes - row indexes
        columnIndexes - column indexes
        values - numerical values
    • Method Detail

      • assign

        public DoubleMatrix2D assign(DoubleFunction function)
        Description copied from class: DoubleMatrix2D
        Assigns the result of a function to each cell; x[row,col] = function(x[row,col]).

        Example:

                 matrix = 2 x 2 matrix          0.5 1.5               2.5 3.5          // change each cell to its sine         matrix.assign(cern.jet.math.Functions.sin);         -->         2 x 2 matrix         0.479426  0.997495          0.598472 -0.350783  
        For further examples, see the package doc.
        Overrides:
        assign in class DoubleMatrix2D
        Parameters:
        function - a function object taking as argument the current cell's value.
        Returns:
        this (for convenience only).
        See Also:
        DoubleFunctions
      • assign

        public DoubleMatrix2D assign(double value)
        Description copied from class: DoubleMatrix2D
        Sets all cells to the state specified by value.
        Overrides:
        assign in class DoubleMatrix2D
        Parameters:
        value - the value to be filled into the cells.
        Returns:
        this (for convenience only).
      • assign

        public DoubleMatrix2D assign(DoubleMatrix2D source)
        Description copied from class: DoubleMatrix2D
        Replaces all cell values of the receiver with the values of another matrix. Both matrices must have the same number of rows and columns. If both matrices share the same cells (as is the case if they are views derived from the same matrix) and intersect in an ambiguous way, then replaces as if using an intermediate auxiliary deep copy of other.
        Overrides:
        assign in class DoubleMatrix2D
        Parameters:
        source - the source matrix to copy from (may be identical to the receiver).
        Returns:
        this (for convenience only).
      • assign

        public DoubleMatrix2D assign(DoubleMatrix2D y,                    DoubleDoubleFunction function)
        Description copied from class: DoubleMatrix2D
        Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]).

        Example:

                 // assign x[row,col] = x[row,col]<sup>y[row,col]</sup>         m1 = 2 x 2 matrix          0 1          2 3          m2 = 2 x 2 matrix          0 2          4 6          m1.assign(m2, cern.jet.math.Functions.pow);         -->         m1 == 2 x 2 matrix         1   1          16 729  
        For further examples, see the package doc.
        Overrides:
        assign in class DoubleMatrix2D
        Parameters:
        y - the secondary matrix to operate on.
        function - a function object taking as first argument the current cell's value of this, and as second argument the current cell's value of y,
        Returns:
        this (for convenience only).
        See Also:
        DoubleFunctions
      • assign

        public SparseDoubleMatrix2D assign(int[] rowIndexes,                          int[] columnIndexes,                          double value,                          DoubleDoubleFunction function)
        Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]), where y is given in the coordinate form with single numerical value.
        Parameters:
        rowIndexes - row indexes of y
        columnIndexes - column indexes of y
        value - numerical value of y
        function - a function object taking as first argument the current cell's value of this, and as second argument the current cell's value of y,
        Returns:
        this (for convenience only).
      • assign

        public SparseDoubleMatrix2D assign(int[] rowIndexes,                          int[] columnIndexes,                          double[] values,                          DoubleDoubleFunction function)
        Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]), where y is given in the coordinate form.
        Parameters:
        rowIndexes - row indexes of y
        columnIndexes - column indexes of y
        values - numerical values of y
        function - a function object taking as first argument the current cell's value of this, and as second argument the current cell's value of y,
        Returns:
        this (for convenience only).
      • cardinality

        public int cardinality()
        Description copied from class: DoubleMatrix2D
        Returns the number of cells having non-zero values; ignores tolerance.
        Overrides:
        cardinality in class DoubleMatrix2D
        Returns:
        cardinality
      • getColumnCompressed

        public SparseCCDoubleMatrix2D getColumnCompressed(boolean sortRowIndexes)
        Returns a new matrix that has the same elements as this matrix, but is in a column-compressed form. This method creates a new object (not a view), so changes in the returned matrix are NOT reflected in this matrix.
        Parameters:
        sortRowIndexes - if true, then row indexes in column compressed matrix are sorted
        Returns:
        this matrix in a column-compressed form
      • getColumnCompressedModified

        public SparseCCMDoubleMatrix2D getColumnCompressedModified()
        Returns a new matrix that has the same elements as this matrix, but is in a column-compressed modified form. This method creates a new object (not a view), so changes in the returned matrix are NOT reflected in this matrix.
        Returns:
        this matrix in a column-compressed modified form
      • getRowCompressed

        public SparseRCDoubleMatrix2D getRowCompressed(boolean sortColumnIndexes)
        Returns a new matrix that has the same elements as this matrix, but is in a row-compressed form. This method creates a new object (not a view), so changes in the returned matrix are NOT reflected in this matrix.
        Parameters:
        sortColumnIndexes - if true, then column indexes in row compressed matrix are sorted
        Returns:
        this matrix in a row-compressed form
      • getRowCompressedModified

        public SparseRCMDoubleMatrix2D getRowCompressedModified()
        Returns a new matrix that has the same elements as this matrix, but is in a row-compressed modified form. This method creates a new object (not a view), so changes in the returned matrix are NOT reflected in this matrix.
        Returns:
        this matrix in a row-compressed modified form
      • ensureCapacity

        public void ensureCapacity(int minCapacity)
        Description copied from class: AbstractMatrix
        Ensures that the receiver can hold at least the specified number of non-zero (non-null) cells without needing to allocate new internal memory. If necessary, allocates new internal memory and increases the capacity of the receiver.

        This default implementation does nothing. Override this method if necessary.

        Overrides:
        ensureCapacity in class AbstractMatrix
        Parameters:
        minCapacity - the desired minimum number of non-zero (non-null) cells.
      • forEachNonZero

        public DoubleMatrix2D forEachNonZero(IntIntDoubleFunction function)
        Description copied from class: DoubleMatrix2D
        Assigns the result of a function to each non-zero cell; x[row,col] = function(x[row,col]). Use this method for fast special-purpose iteration. If you want to modify another matrix instead of this (i.e. work in read-only mode), simply return the input value unchanged. Parameters to function are as follows: first==row, second==column, third==nonZeroValue.
        Overrides:
        forEachNonZero in class DoubleMatrix2D
        Parameters:
        function - a function object taking as argument the current non-zero cell's row, column and value.
        Returns:
        this (for convenience only).
      • getQuick

        public double getQuick(int row,              int column)
        Description copied from class: DoubleMatrix2D
        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.
      • index

        public long index(int row,         int column)
        Description copied from class: AbstractMatrix2D
        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)
        Description copied from class: DoubleMatrix2D
        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)
        Description copied from class: DoubleMatrix2D
        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.
      • setQuick

        public void setQuick(int row,            int column,            double value)
        Description copied from class: DoubleMatrix2D
        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.
      • trimToSize

        public void trimToSize()
        Description copied from class: AbstractMatrix
        Releases any superfluous internal memory. An application can use this operation to minimize the storage of the receiver.

        This default implementation does nothing. Override this method if necessary.

        Overrides:
        trimToSize in class AbstractMatrix
      • vectorize

        public DoubleMatrix1D vectorize()
        Description copied from class: DoubleMatrix2D
        Returns a vector obtained by stacking the columns of the matrix on top of one another.
        Specified by:
        vectorize in class DoubleMatrix2D
        Returns:
        a vector of columns of this matrix.
      • zMult

        public DoubleMatrix1D zMult(DoubleMatrix1D y,                   DoubleMatrix1D z,                   double alpha,                   double beta,                   boolean transposeA)
        Description copied from class: DoubleMatrix2D
        Linear algebraic matrix-vector multiplication; z = alpha * A * y + beta*z. z[i] = alpha*Sum(A[i,j] * y[j]) + beta*z[i], i=0..A.rows()-1, j=0..y.size()-1 . Where A == this.
        Note: Matrix shape conformance is checked after potential transpositions.
        Overrides:
        zMult in class DoubleMatrix2D
        Parameters:
        y - the source vector.
        z - the vector where results are to be stored. Set this parameter to null to indicate that a new result vector shall be constructed.
        Returns:
        z (for convenience only).
      • zMult

        public DoubleMatrix2D zMult(DoubleMatrix2D B,                   DoubleMatrix2D C,                   double alpha,                   double beta,                   boolean transposeA,                   boolean transposeB)
        Description copied from class: DoubleMatrix2D
        Linear algebraic matrix-matrix multiplication; C = alpha * A x B + beta*C. C[i,j] = alpha*Sum(A[i,k] * B[k,j]) + beta*C[i,j], k=0..n-1.
        Matrix shapes: A(m x n), B(n x p), C(m x p).
        Note: Matrix shape conformance is checked after potential transpositions.
        Overrides:
        zMult in class DoubleMatrix2D
        Parameters:
        B - the second source matrix.
        C - the matrix where results are to be stored. Set this parameter to null to indicate that a new result matrix shall be constructed.
        Returns:
        C (for convenience only).

SCaVis 2.0 © jWork.ORG