Package edu.gsu.cs.dmlab.imageproc.imageparam.util

Class MatrixUtil

java.lang.Object

edu.gsu.cs.dmlab.imageproc.imageparam.util.MatrixUtil

public abstract class MatrixUtil
extends Object

This class is designed to extract sub-matrices, in the form of a 2D or 1D array. The assumption is that the sub-matrix is always a square matrix. Note: This class follows the convention of reading/writing matrices in a row-by-row fashion.

Author:

Azim Ahmadzadeh, Data Mining Lab, Georgia State University

Constructor Summary

Constructors

Constructor	Description
MatrixUtil()

Method Summary

Modifier and Type	Method	Description
static double[][]	convertTo2DArray(double[] array, int width, int height)	This method converts a 1D array to a 2D array given the expected width and height
static double[]	getSubMatrixAsArray(double[][] m, int startingRow, int startingCol, int pSize)	For a given 2D matrix, this method returns a sub-matrix in the form of a 1D array.
static double[][]	getSubMatrixAsMatrix(double[][] m, int startingRow, int startingCol, int pSize)	For a given 2D matrix, this method returns a sub-matrix in the form of a 2D array.

Methods inherited from class java.lang.Object

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

Constructor Detail

MatrixUtil

public MatrixUtil()

Method Detail

getSubMatrixAsArray

public static double[] getSubMatrixAsArray(double[][] m,
                                           int startingRow,
                                           int startingCol,
                                           int pSize)

For a given 2D matrix, this method returns a sub-matrix in the form of a 1D array. The output array is formed by putting each row of the sub-matrix concatenated to its previous row. (As opposed to a column-by-column concatenation.)

Parameters:

m - the given matrix

startingCol - the starting row (width) where the sub-matrix should be extracted.

startingRow - the starting col (height) where the sub-matrix should be extracted.

pSize - the size of the square sub-matrix. (Zero or negative values are not allowed.)

Returns:

a 1D array representing the sub-matrix

getSubMatrixAsMatrix

public static double[][] getSubMatrixAsMatrix(double[][] m,
                                              int startingRow,
                                              int startingCol,
                                              int pSize)

For a given 2D matrix, this method returns a sub-matrix in the form of a 2D array.

Parameters:

m - the given matrix

startingRow - the starting row (width) where the sub-matrix should be extracted.

startingCol - the starting col (height) where the sub-matrix should be extracted.

pSize - the size of the square sub-matrix. (Zero or negative values are not allowed.)

Returns:

a 2D array representing the sub-matrix

convertTo2DArray

public static double[][] convertTo2DArray(double[] array,
                                          int width,
                                          int height)

This method converts a 1D array to a 2D array given the expected width and height

Parameters:

array -

width - is similar to output.length

height - is similar to output[0].length

Returns:

A 2D array of size width X height