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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;
/**
* A Matrix represents a 2-dimensional matrix.
* Matrices provide a fixed number of rows and columns, with values
* for each row and column.
*
* An optional operation {@link #setValue(int,int,double)} allows
* values to be set.
*
*
Two matrices should be equal if they have the same number of
* rows and columns and every value is equal. Their hash codes should
* be defined as specified in the documentation for {@link
* #hashCode()}.
*
* @author Bob Carpenter
* @version 3.0
* @since LingPipe2.0
*/
public interface Matrix {
/**
* Returns the number of rows in the matrix.
*
* @return The number of rows in the matrix.
*/
public int numRows();
/**
* Returns the number of columns in the matrix.
*
* @return The number of columns in the matrix.
*/
public int numColumns();
/**
* Returns the value in the matrix at the specified row and
* column.
*
* @param row The specified row.
* @param column The specified column.
* @return The value in the matrix at the specified row and
* column.
* @throws IndexOutOfBoundsException If the row or column index
* are out of bounds for this matrix.
*/
public double value(int row, int column);
/**
* Sets the value for the specified row and column to be
* the specified value.
*
*
This operation is optional. Implementations may
* throw unsupported operation exceptions.
*
* @param row Specified row.
* @param column Specified column.
* @param value New value for specified row and column.
* @throws UnsupportedOperationException If this operation is not
* supported.
* @throws IndexOutOfBoundsException If the row or column index
* are out of bounds for this matrix.
*/
public void setValue(int row, int column, double value);
/**
* Returns the vector of values in the specified row. The
* dimensionality of the returned vector will be the number of
* columns in this matrix.
*
*
Changes to the returned vector will affect this matrix and
* vice-versa. To circumvent this dependency, clone the result.
*
* @param row Index of row whose vector is returned.
* @return Row vector for specified row.
* @throws IndexOutOfBoundsException If the row index is
* out of bounds for this matrix.
*/
public Vector rowVector(int row);
/**
* Returns the vector of values in the specified column.
* The dimensionality of the returned vector will be
* the number of rows in this matrix.
*
*
Changes to the returned vector will affect this matrix and
* vice-versa. To circumvent this dependency, clone the result.
*
* @param column Index of column whose vector is returned.
* @return Column vector for specified column.
* @throws IndexOutOfBoundsException If the column index is
* out of bounds for this matrix.
*/
public Vector columnVector(int column);
/**
* Returns true if the specified object is a matrix
* with the same number of rows and columns and the same value in
* every cell as this matrix.
*
* @param that Object to test for equality with this matrix.
* @return true if the specified object is a matrix
* with the same values and number of rows and columns as this
* matrix.
*/
public boolean equals(Object that);
/**
* Return the hash code for the matrix. The hash code of a
* matrix is computed value-wise as if it were a
* java.util.List of java.lang.Double values
* ordered row by row:
*
*
* int hashCode = 1;
* for (int i = 0; i < numRows(); ++i) {
* for (int j = 0; j < numColumns(); ++j) {
* int v = Double.doubleToLongBits(value(i,j));
* int valHash = (int) (v^(v>>>32));
* hashCode = 31*hashCode + valHash;
* }
* }
*
*
* Note that this definition is consistent with {@link #equals(Object)}.
*
* @return The hash code for this matrix.
*/
public int hashCode();
}