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/*
* LingPipe v. 4.1.0
* Copyright (C) 2003-2011 Alias-i
*
* This program is licensed under the Alias-i Royalty Free License
* Version 1 WITHOUT ANY WARRANTY, without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Alias-i
* Royalty Free License Version 1 for more details.
*
* You should have received a copy of the Alias-i Royalty Free License
* Version 1 along with this program; if not, visit
* http://alias-i.com/lingpipe/licenses/lingpipe-license-1.txt or contact
* Alias-i, Inc. at 181 North 11th Street, Suite 401, Brooklyn, NY 11211,
* +1 (718) 290-9170.
*/
package com.aliasi.matrix;
/**
* An AbstractMatrix implements most of a matrix's
* functionality in terms of methods for accessing numbers of rows and
* columns and values.
*
* @author Bob Carpenter
* @version 3.0
* @since LingPipe2.0
*/
public abstract class AbstractMatrix implements Matrix {
/**
* Construct an abstract matrix.
*/
protected AbstractMatrix() {
/* do nothing */
}
public abstract int numRows();
public abstract int numColumns();
public abstract double value(int row, int column);
/**
* Throw an unsupported operation exception. This
* method should be overriden by value mutable subclasses.
*
* @param row Ignored.
* @param column Ignored.
* @param value Ignored.
* @throws UnsupportedOperationException If not overridden by a
* subclass implementation.
* @throws IndexOutOfBoundsException If the row or column indexes
* are out of bounds.
*/
public void setValue(int row, int column, double value) {
throw new UnsupportedOperationException();
}
/**
* Returns the specified row of this matrix. The vector returned
* is backed by this matrix, and changes to its values or labels
* affect this matrix. The returned vector may be cloned to
* produce an equivalent vector that is not linked to this matrix.
*
* No check is made that the row is within current bounds of the
* matrix, but attempts to access values for a row matrix that
* is out of bounds will throw a runtime exception if the underlying
* matrix's value(int,int) method throws an exception..
*
* @param row Row whose vector is returned.
* @return Vector for the specified row.
* @throws IndexOutOfBoundsException If the row index is out of bounds.
*/
public Vector rowVector(int row) {
return new MatrixBackedVector.Row(this,row);
}
/**
* Returns the specified column of this matrix. The vector
* returned is backed by this matrix, and changes to its values or
* labels affect this matrix. The returned vector may be cloned
* to produce an equivalent vector that is not linked to this
* matrix.
*
*
No check is made that the column is within current bounds of
* the matrix, but attempts to access values for a column matrix
* that is out of bounds will throw a runtime exception if the
* underlying matrix's value(int,int) method throws
* an exception.
*
* @param column Column whose vector is returned.
* @return Vector for the specified column.
*/
public Vector columnVector(int column) {
return new MatrixBackedVector.Column(this,column);
}
/**
* Return true if the specified object is a matrix of
* the same dimensionality with the same values. Note that labels
* are ignored in establishing matrix identity. This definition
* is consistent witht he definition of {@link #hashCode()}.
*
* @param that Object to test for equality with this matrix.
* @return true if the specified object is a matrix
* with the same dimensionality and values as this matrix.
*
*/
@Override
public boolean equals(Object that) {
if (!(that instanceof Matrix)) return false;
Matrix thatMatrix = (Matrix) that;
if (numRows() != thatMatrix.numRows()) return false;
if (numColumns() != thatMatrix.numColumns()) return false;
for (int i = numRows(); --i >= 0; )
if (!rowVector(i).equals(thatMatrix.rowVector(i)))
return false;
return true;
}
/**
* Returns a hash code as specified in the Matrix
* interface's documentation.
*
* @return Hash code for this matrix.
*/
@Override
public int hashCode() {
int code = 1;
int numRows = numRows();
int numColumns = numColumns();
for (int i = 0; i < numRows; ++i)
for (int j = 0; j < numColumns; ++j) {
long v = Double.doubleToLongBits(value(i,j));
int valHash = (int)(v^(v>>>32));
code = 31 * code + valHash;
}
return code;
}
}