Mega Code Archive
This class represents a lower (or upper) triangle matrix that stores ints
<![CDATA[
/**
* created 23.01.2008
*
* @by Marc Woerlein (woerlein@informatik.uni-erlangen.de)
*
* Copyright 2008 Marc Woerlein
*
* This file is part of parsemis.
*
* Licence:
* LGPL: http://www.gnu.org/licenses/lgpl.html
* EPL: http://www.eclipse.org/org/documents/epl-v10.php
* See the LICENSE file in the project's top-level directory for details.
*/
//package de.parsemis.utils;
/**
* This class represents a lower (or upper) triangle matrix that stores ints.
*
* @author Thorsten Meinl (Thorsten.Meinl@informatik.uni-erlangen.de)
* @author Marc Woerlein (woerlein@informatik.uni-erlangen.de)
*
*/
public class HalfIntMatrix{
/** the array holding the complete triangle matrix */
private final int[] matrix;
private final int size, initialValue;
/**
* Creates a new HalfIntMatrix that is an exact copy of the given template
*
* @param template
* a HalfIntMatrix that should be copied
*/
public HalfIntMatrix(final HalfIntMatrix template) {
this(template, 0);
}
/**
* Creates a new HalfIntMatrix that is an exact copy of the given template
*
* @param template
* a HalfIntMatrix that should be copied
* @param reserveNewNodes
* the number of new nodes for which space should be reserved or
* removed
*/
public HalfIntMatrix(final HalfIntMatrix template, final int reserveNewNodes) {
this.size = (template.size + reserveNewNodes);
this.initialValue = template.initialValue;
this.matrix = new int[((size * size + size) / 2)];
System.arraycopy(template.matrix, 0, matrix, 0,
reserveNewNodes >= 0 ? template.matrix.length : matrix.length);
for (int i = template.matrix.length; i < matrix.length; i++) {
matrix[i] = initialValue;
}
}
/**
* Creates a new HalfIntMatrix with the given size and initial values
*
* @param initialSize
* the size of the matrix in rows (or columns)
* @param initialValue
* the initial value of each matrix element
*/
public HalfIntMatrix(final int initialSize, final int initialValue) {
this.size = initialSize;
this.initialValue = initialValue;
this.matrix = new int[((size * size + size) / 2)];
for (int i = 0; i < matrix.length; i++) {
matrix[i] = initialValue;
}
}
/*
* (non-Javadoc)
*
* @see de.parsemis.utils.IntMatrix#exchangeRows(int, int)
*/
public void exchangeRows(int rowA, int rowB) {
if (rowA == rowB) {
return;
}
if (rowA > rowB) {
final int t = rowA;
rowA = rowB;
rowB = t;
}
int i = 0;
for (; i < rowA; i++) {
swap(rowA, i, rowB, i);
}
for (i++; i < rowB; i++) {
swap(rowA, i, rowB, i);
}
for (i++; i < size; i++) {
swap(rowA, i, rowB, i);
}
swap(rowA, rowA, rowB, rowB);
swap(rowA, rowB, rowB, rowA);
}
/*
* (non-Javadoc)
*
* @see de.parsemis.utils.IntMatrix#get(int, int)
*/
public int get(final int row, final int col) {
assert row >= 0 && col >= 0 && row < size && col < size : "row/col out of bounds: "
+ row + "/" + col + " size: " + size;
return matrix[idx(row, col)];
}
private final int idx(final int row, final int col) {
if (row < col) {
return col * (col + 1) / 2 + row;
} else {
return row * (row + 1) / 2 + col;
}
}
/*
* (non-Javadoc)
*
* @see de.parsemis.utils.IntMatrix#set(int, int, int)
*/
public void set(final int row, final int col, final int value) {
assert row >= 0 && col >= 0 && row < size && col < size : "row/col out of bounds: "
+ row + "/" + col + " size: " + size;
matrix[idx(row, col)] = value;
}
/*
* (non-Javadoc)
*
* @see de.parsemis.utils.IntMatrix#size()
*/
public int size() {
return size;
}
private final void swap(final int r1, final int c1, final int r2,
final int c2) {
swap(matrix, idx(r1, c1), idx(r2, c2));
}
/**
* swaps the values of the array at position i and j
*
* @param array
* @param i
* @param j
*/
public static void swap(final int array[], final int i, final int j) {
final int temp = array[i];
array[i] = array[j];
array[j] = temp;
}
}
]]>