drasys.or.matrix
Class CompressedRowMatrix

java.lang.Object
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  +--drasys.or.matrix.RealContainer
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        +--drasys.or.matrix.Matrix
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              +--drasys.or.matrix.CompressedMatrix
                    |
                    +--drasys.or.matrix.CompressedRowMatrix

public class CompressedRowMatrix

extends CompressedMatrix

A sparse compressed resizable row-major matrix of double values. This matrix is efficient for numerical computing, especially row-wise computations. Its also efficient for adding new rows and new elements to the last row.

The most efficient way to build this matrix is row-wise by adding elements only to the last row. This reduces the memory copying caused by adding elements at the head of the arrays. The attribute 'fillInSpace' can be used to reserve some extra elements for each row fill-in is unavoidable. If the matrix is constructed strictly row-wise then 'fillInSpace' should be set to zero to conserve memory.

There is more detailed information available about the internal storage format.

References:

Matrix Computations (Johns Hopkins Studies in the Mathematical Sciences)
    Gene H. Golub, Charles F. Van Loan (Contributor) / Paperback / Published 1996
Numerical Recipes in C : The Art of Scientific Computing
    William H. Press, et al / Hardcover / Published 1993
Parallel Algorithms for Matrix Computations
    K.A. Gallivan / Paperback / Published 1990

See Also:

Serialized Form

Fields inherited from class drasys.or.matrix.RealContainer

_epsilon, _globalEpsilon

 

Constructor Summary

CompressedRowMatrix(double[][] array, int fillInSpace)           Creates a sparse matrix from the contents of 'array'.

CompressedRowMatrix(double[][] array, int fillInSpace, double epsilon)           Creates a sparse matrix from the contents of 'array'.

CompressedRowMatrix(int capacityOfRows, int sizeOfColumns, int fillInSpace)           Constructs a compressed sparse row-major matrix with an explicit row capacity and column size.

CompressedRowMatrix(int capacityOfRows, int sizeOfColumns, int fillInSpace, int capacityOfElements)

CompressedRowMatrix(MatrixI matrix, int fillInSpace)

CompressedRowMatrix(VectorI vector, int fillInSpace)

 

Method Summary
void	addColumn(VectorI vector)           Adds a new column and any non-null elements in vector to the end of the matrix .
void	addRow(VectorI vector)           Adds a new row and any non-null elements in vector to the end of the matrix .
void	buildColumnIndex()           Build the column index structure.
int	capacityOfColumns()           Returns the number of columns the matrix can hold without allocating more memory.
int	capacityOfRows()           Returns the number of rows the matrix can hold without allocating more memory.
java.util.Enumeration	columnElements(int column)           Returns an enumeration of the non-null elements in a column.
void	deleteColumnIndex()           Delete the column index structure.
double	elementAt(int row, int column)           Gets an element's value from the matrix.
java.util.Enumeration	elements()           Returns an enumeration of the non-null elements in the matrix.
double[][]	getArray()           Returns a new two-dimensional array containing the values in matrix.
int[]	getColumnEndArray()           Return the array used to indicate the end of each column in the column index.
int[]	getColumnIndexArray()           Return the array used to hold the column indices.
int[]	getRowBeginArray()           Return the array used to hold the index of the first element in each row.
int[]	getRowIndexArray()           Return the array used to hold the row indices for the column index.
int[]	getRowSizeArray()           Return the array used to hold the number of elements in each row.
int[]	getValueIndexArray()           Return the array used to hold the value indices for the column index.
boolean	isColumnMajor()           Returns true if the matrix is column-major.
boolean	isNull(int row, int column)           Returns true if an element has no value associated with it.
boolean	isRowMajor()           Returns true if the matrix is row-major.
java.util.Enumeration	rowElements(int row)           Returns an enumeration of the non-null elements in a row.
void	setCapacity(int capacityOfRows, int capacityOfColumns)           Allocates memory so the matrix can hold this many rows and columns without reallocating memory.
void	setElementAt(int row, int column, double value)           Sets an element's value in the matrix.
void	setSize(int sizeOfRows, int sizeOfColumns)           Sets the number of rows and columns in the matrix.
int	sizeOfElements()           Returns the number of non-null elements in the matrix.
double	sum(int rowBegin, int rowEnd, int columnBegin, int columnEnd)           Returns the sum of all of the elements in the sub-matrix. Computes sum(a[i][j]). Where: i = {rowBegin,...,(rowEnd-1)} j = {columBegin,...,(columnEnd-1)}
double	sumOfSquaredDifferences(int rowBegin, int rowEnd, int columnBegin, int columnEnd, double scaler)           Returns the sum of the squared differences between the elements and a scaler. Computes sum((a[i][j]-scaler)^2). Where: i = {rowBegin,...,(rowEnd-1)} j = {columBegin,...,(columnEnd-1)}
double	sumOfSquares(int rowBegin, int rowEnd, int columnBegin, int columnEnd)           Returns the sum of the squares of all of the elements in the sub-matrix. Computes sum(a[i][j]^2). Where: i = {rowBegin,...,(rowEnd-1)} j = {columBegin,...,(columnEnd-1)}

 

Methods inherited from class drasys.or.matrix.CompressedMatrix

getValueArray, setCapacityOfElements, setElements, sizeOfColumns, sizeOfRows

 

Methods inherited from class drasys.or.matrix.Matrix

equals, equals, setColumn, setDiagonal, setElements, setRow, sum, sum, sumOfSquaredDifferences, sumOfSquaredDifferences, sumOfSquares, sumOfSquares, toString

 

Methods inherited from class drasys.or.matrix.RealContainer

equals, getEpsilon, getGlobalEpsilon, setEpsilon, setGlobalEpsilon

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Constructor Detail

CompressedRowMatrix

public CompressedRowMatrix(int capacityOfRows,
                           int sizeOfColumns,
                           int fillInSpace)

Constructs a compressed sparse row-major matrix with an explicit row capacity and column size. The initial row size is zero.

CompressedRowMatrix

public CompressedRowMatrix(int capacityOfRows,
                           int sizeOfColumns,
                           int fillInSpace,
                           int capacityOfElements)

CompressedRowMatrix

public CompressedRowMatrix(double[][] array,
                           int fillInSpace)

Creates a sparse matrix from the contents of 'array'. All of the elements will be added.

CompressedRowMatrix

public CompressedRowMatrix(double[][] array,
                           int fillInSpace,
                           double epsilon)

Creates a sparse matrix from the contents of 'array'. Elements in 'array' which equal 0.0 to within 'epsilon' will not be added. The matrix epsilon will be set to 'epsilon'.

CompressedRowMatrix

public CompressedRowMatrix(MatrixI matrix,
                           int fillInSpace)

CompressedRowMatrix

public CompressedRowMatrix(VectorI vector,
                           int fillInSpace)

sizeOfElements

public int sizeOfElements()

Returns the number of non-null elements in the matrix.

capacityOfRows

public int capacityOfRows()

Returns the number of rows the matrix can hold without allocating more memory.

capacityOfColumns

public int capacityOfColumns()

Returns the number of columns the matrix can hold without allocating more memory.

getColumnIndexArray

public int[] getColumnIndexArray()

Return the array used to hold the column indices.

getRowSizeArray

public int[] getRowSizeArray()

Return the array used to hold the number of elements in each row.

getRowBeginArray

public int[] getRowBeginArray()

Return the array used to hold the index of the first element in each row.

deleteColumnIndex

public void deleteColumnIndex()

Delete the column index structure.

buildColumnIndex

public void buildColumnIndex()

Build the column index structure.

getRowIndexArray

public int[] getRowIndexArray()

Return the array used to hold the row indices for the column index.

Returns:

null if the column index is not built.

getColumnEndArray

public int[] getColumnEndArray()

Return the array used to indicate the end of each column in the column index.

Returns:

null if the column index is not built.

getValueIndexArray

public int[] getValueIndexArray()

Return the array used to hold the value indices for the column index.

Returns:

null if the column index is not built.

isRowMajor

public boolean isRowMajor()

Returns true if the matrix is row-major.

isColumnMajor

public boolean isColumnMajor()

Returns true if the matrix is column-major.

addRow

public void addRow(VectorI vector)

Adds a new row and any non-null elements in vector to the end of the matrix . If 'vector' is null then no new elements will be modified in the new row.

addColumn

public void addColumn(VectorI vector)

Adds a new column and any non-null elements in vector to the end of the matrix . If 'vector' is null then no new elements will be changed in the new column.

setSize

public void setSize(int sizeOfRows,
                    int sizeOfColumns)

Sets the number of rows and columns in the matrix. If the new size is smaller than the original then the matrix will be emptied.

setCapacity

public void setCapacity(int capacityOfRows,
                        int capacityOfColumns)

Allocates memory so the matrix can hold this many rows and columns without reallocating memory.

setElementAt

public void setElementAt(int row,
                         int column,
                         double value)

Sets an element's value in the matrix.

isNull

public boolean isNull(int row,
                      int column)

Returns true if an element has no value associated with it. Elements which have no value assigned return 0.0 when accessed.

elementAt

public double elementAt(int row,
                        int column)

Gets an element's value from the matrix.

Tags copied from interface: MatrixI

Returns:

zero is the element is null

getArray

public double[][] getArray()

Returns a new two-dimensional array containing the values in matrix. The rows of the array hold the rows of the matrix.

Overrides:

getArray in class Matrix

rowElements

public java.util.Enumeration rowElements(int row)

Returns an enumeration of the non-null elements in a row. The elements are enumerated in random order.

Overrides:

rowElements in class Matrix

Returns:

an enumeration whose elements are of type MatrixElementI

columnElements

public java.util.Enumeration columnElements(int column)

Returns an enumeration of the non-null elements in a column. The elements are enumerated in random order. This method will build the column index if it doesn't exist.

Overrides:

columnElements in class Matrix

Returns:

an enumeration whose elements are of type MatrixElementI

elements

public java.util.Enumeration elements()

Returns an enumeration of the non-null elements in the matrix. The elements are enumerated in random order.

Overrides:

elements in class Matrix

Returns:

an enumeration whose elements are of type MatrixElementI

sum

public double sum(int rowBegin,
                  int rowEnd,
                  int columnBegin,
                  int columnEnd)

Returns the sum of all of the elements in the sub-matrix.
Computes sum(a[i][j]).
Where: i = {rowBegin,...,(rowEnd-1)}
j = {columBegin,...,(columnEnd-1)}

Overrides:

sum in class Matrix

sumOfSquares

public double sumOfSquares(int rowBegin,
                           int rowEnd,
                           int columnBegin,
                           int columnEnd)

Returns the sum of the squares of all of the elements in the sub-matrix.
Computes sum(a[i][j]^2).
Where: i = {rowBegin,...,(rowEnd-1)}
j = {columBegin,...,(columnEnd-1)}

Overrides:

sumOfSquares in class Matrix

sumOfSquaredDifferences

public double sumOfSquaredDifferences(int rowBegin,
                                      int rowEnd,
                                      int columnBegin,
                                      int columnEnd,
                                      double scaler)

Returns the sum of the squared differences between the elements and a scaler.
Computes sum((a[i][j]-scaler)^2).
Where: i = {rowBegin,...,(rowEnd-1)}
j = {columBegin,...,(columnEnd-1)}

Overrides:

sumOfSquaredDifferences in class Matrix