cern.colt.matrix.impl

Class DenseObjectMatrix2D

java.lang.Object

cern.colt.PersistentObject

cern.colt.matrix.impl.AbstractMatrix

cern.colt.matrix.impl.AbstractMatrix2D

cern.colt.matrix.ObjectMatrix2D

cern.colt.matrix.impl.DenseObjectMatrix2D

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class DenseObjectMatrix2D
extends ObjectMatrix2D

Dense 2-d matrix holding Object elements. First see the package summary and javadoc tree view to get the broad picture.

Implementation:

Internally holds one single contigous one-dimensional array, addressed in row major. Note that this implementation is not synchronized.

Memory requirements:

memory [bytes] = 8*rows()*columns(). Thus, a 1000*1000 matrix uses 8 MB.

Time complexity:

O(1) (i.e. constant time) for the basic operations get, getQuick, set, setQuick and size,

Cells are internally addressed in row-major. Applications demanding utmost speed can exploit this fact. Setting/getting values in a loop row-by-row is quicker than column-by-column. 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:

Serialized Form

Field Summary

Fields inherited from class cern.colt.PersistentObject

serialVersionUID

Constructor Summary

Constructors

Constructor and Description
DenseObjectMatrix2D(int rows, int columns) Constructs a matrix with a given number of rows and columns.
DenseObjectMatrix2D(java.lang.Object[][] values) Constructs a matrix with a copy of the given values.

Method Summary

Modifier and Type	Method and Description
ObjectMatrix2D	assign(java.lang.Object[][] values) Sets all cells to the state specified by values.
ObjectMatrix2D	assign(ObjectFunction function) Assigns the result of a function to each cell; x[row,col] = function(x[row,col]).
ObjectMatrix2D	assign(ObjectMatrix2D source) Replaces all cell values of the receiver with the values of another matrix.
ObjectMatrix2D	assign(ObjectMatrix2D y, ObjectObjectFunction function) Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]).
java.lang.Object	getQuick(int row, int column) Returns the matrix cell value at coordinate [row,column].
ObjectMatrix2D	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.
ObjectMatrix1D	like1D(int size) Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver.
void	setQuick(int row, int column, java.lang.Object value) Sets the matrix cell at coordinate [row,column] to the specified value.

Methods inherited from class cern.colt.matrix.ObjectMatrix2D

aggregate, aggregate, assign, cardinality, copy, equals, equals, get, getNonZeros, like, set, toArray, toString, viewColumn, viewColumnFlip, viewDice, viewPart, viewRow, viewRowFlip, viewSelection, viewSelection, viewSorted, viewStrides

Methods inherited from class cern.colt.matrix.impl.AbstractMatrix2D

checkShape, checkShape, columns, rows, size, toStringShort

Methods inherited from class cern.colt.matrix.impl.AbstractMatrix

ensureCapacity, trimToSize

Methods inherited from class cern.colt.PersistentObject

clone

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DenseObjectMatrix2D

public DenseObjectMatrix2D(java.lang.Object[][] 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:

java.lang.IllegalArgumentException - if for any 1 <= row < values.length: values[row].length != values[row-1].length.

DenseObjectMatrix2D

public DenseObjectMatrix2D(int rows,
                           int columns)

Constructs a matrix with a given number of rows and columns. 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:

java.lang.IllegalArgumentException - if rows<0 || columns<0 || (Object)columns*rows > Integer.MAX_VALUE.

Method Detail

assign

public ObjectMatrix2D assign(java.lang.Object[][] values)

Sets all cells to the state specified by values. values is required to have the form values[row][column] and have exactly the same number of rows and columns as the receiver.

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

Overrides:

assign in class ObjectMatrix2D

Parameters:

values - the values to be filled into the cells.

Returns:

this (for convenience only).

Throws:

java.lang.IllegalArgumentException - if values.length != rows() || for any 0 <= row < rows(): values[row].length != columns().

assign

public ObjectMatrix2D assign(ObjectFunction function)

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 ObjectMatrix2D

Parameters:

function - a function object taking as argument the current cell's value.

Returns:

this (for convenience only).

See Also:

Functions

assign

public ObjectMatrix2D assign(ObjectMatrix2D source)

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 ObjectMatrix2D

Parameters:

source - the source matrix to copy from (may be identical to the receiver).

Returns:

this (for convenience only).

Throws:

java.lang.IllegalArgumentException - if columns() != source.columns() || rows() != source.rows()

assign

public ObjectMatrix2D assign(ObjectMatrix2D y,
                             ObjectObjectFunction function)

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]y[row,col]
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 ObjectMatrix2D

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).

Throws:

java.lang.IllegalArgumentException - if columns() != other.columns() || rows() != other.rows()

See Also:

Functions

getQuick

public java.lang.Object 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 ObjectMatrix2D

Parameters:

row - the index of the row-coordinate.

column - the index of the column-coordinate.

Returns:

the value at the specified coordinate.

like

public ObjectMatrix2D 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 DenseObjectMatrix2D the new matrix must also be of type DenseObjectMatrix2D, if the receiver is an instance of type SparseObjectMatrix2D the new matrix must also be of type SparseObjectMatrix2D, etc. In general, the new matrix should have internal parametrization as similar as possible.

Specified by:

like in class ObjectMatrix2D

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 ObjectMatrix1D 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 DenseObjectMatrix2D the new matrix must be of type DenseObjectMatrix1D, if the receiver is an instance of type SparseObjectMatrix2D the new matrix must be of type SparseObjectMatrix1D, etc.

Specified by:

like1D in class ObjectMatrix2D

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,
                     java.lang.Object 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 ObjectMatrix2D

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.