SparseTriangularMatrix.java

package ca.pfv.spmf.datastructures.triangularmatrix;

import java.util.HashMap;
import java.util.Map;

import ca.pfv.spmf.algorithms.frequentpatterns.charm.AlgoCharm_Bitset;
import ca.pfv.spmf.algorithms.frequentpatterns.eclat.AlgoEclat;
import ca.pfv.spmf.algorithms.frequentpatterns.eclat.AlgoEclat_Bitset;
/* This file is copyright (c) 2008-2013 Philippe Fournier-Viger
* 
* This file is part of the SPMF DATA MINING SOFTWARE
* (http://www.philippe-fournier-viger.com/spmf).
* 
* SPMF is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
* 
* SPMF is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU General Public License for more details.
* You should have received a copy of the GNU General Public License along with
* SPMF. If not, see <http://www.gnu.org/licenses/>.
*/


/**
 * This class is for creating a triangular matrix of integers by using HashMaps (a sparse matrix rather than a full matrix).
 * See the TriangularMatrixArray class for more details about what is a triangular matrix.
 * 
 * @see AbstractTriangularMatrix
 * @see TriangularMatrix
 * @see AlgoCharm_Bitset
 * @see AlgoEclat_Bitset
 * @see AlgoEclat
 * @author Philippe Fournier-Viger
 */
public class SparseTriangularMatrix implements AbstractTriangularMatrix {
	
	// the triangular matrix is a hashmap of hashmaps
	// where the key is an item I, then the value is a map where each entry is a key representing an item J
	// and a value representing the count of {I, J}.
	private Map<Integer, Map<Integer, Integer>> matrix = new HashMap<Integer, Map<Integer, Integer>>();

	/**
	 * Constructor of a new triangular matrix.
	 * @param elementCount the desired number of lines in the matrix.
	 */
	public SparseTriangularMatrix(){

	}
	
	/**
	 * This constructor is for compatibility with the other TriangularMatrix implementation.
	 * The parameter "itemCount" is not used.
	 * @param itemCount
	 */
	public SparseTriangularMatrix(int itemCount){

	}
	
	/* (non-Javadoc)
	 * @see ca.pfv.spmf.datastructures.triangularmatrix.AbstractTriangularMatrix#toString()
	 */
	public String toString() {
		// create a string buffer
		StringBuilder temp = new StringBuilder();
		// for each row
		for (int i = 0; i < matrix.keySet().size(); i++) {
			temp.append(i);
			temp.append(": ");
			// for each column
			for (int j = 0; j < matrix.get(i).size(); j++) {
				temp.append(matrix.get(i).get(j)); // add the value at position i,j
				temp.append(" ");
			}
			temp.append("\n");
		}
		return temp.toString();
	}

	/* (non-Javadoc)
	 * @see ca.pfv.spmf.datastructures.triangularmatrix.AbstractTriangularMatrix#incrementCount(int, int)
	 */
	public void incrementCount(int i, int j) {
		if(i < j) {
			// First get the map of i
			Map<Integer, Integer> mapCount = matrix.get(i);
			if(mapCount == null) {
				mapCount = new HashMap<Integer,Integer>();
				matrix.put(i, mapCount);
				mapCount.put(j, 1);
			}else {
				// Second, get the count of i,j
				Integer count = mapCount.get(j);
				if(count == null) {
					mapCount.put(j, 1);
				}else {
					mapCount.put(j, ++count);
				}
			}
		}else {
			// First get the map of j
			Map<Integer, Integer> mapCount = matrix.get(j);
			if(mapCount == null) {
				mapCount = new HashMap<Integer,Integer>();
				matrix.put(j, mapCount);
				mapCount.put(i, 1);
			}else {
				// Second, get the count of i,j
				Integer count = mapCount.get(i);
				if(count == null) {
					mapCount.put(i, 1);
				}else {
					mapCount.put(i, ++count);
				}
			}
		}
	}
	
	/* (non-Javadoc)
	 * @see ca.pfv.spmf.datastructures.triangularmatrix.AbstractTriangularMatrix#getSupportForItems(int, int)
	 */
	public int getSupportForItems(int i, int j){
		if(i < j) {
			// First get the map of i
			Map<Integer, Integer> mapCount = matrix.get(i);
			if(mapCount == null) {
				return 0;
			}else {
				// Second, get the count of i,j
				Integer count = mapCount.get(j);
				if(count == null) {
					return 0;
				}else {
					return count;
				}
			}
		}else {
			// First get the map of i
			Map<Integer, Integer> mapCount = matrix.get(j);
			if(mapCount == null) {
				return 0;
			}else {
				// Second, get the count of i,j
				Integer count = mapCount.get(i);
				if(count == null) {
					return 0;
				}else {
					return count;
				}
			}
		}
	}

	/* (non-Javadoc)
	 * @see ca.pfv.spmf.datastructures.triangularmatrix.AbstractTriangularMatrix#setSupport(java.lang.Integer, java.lang.Integer, int)
	 */
	public void setSupport(Integer i, Integer j, int support) {
		if(i < j) {
			// First get the map of i
			Map<Integer, Integer> mapCount = matrix.get(i);
			if(mapCount == null) {
				mapCount = new HashMap<Integer,Integer>();
				matrix.put(i, mapCount);
				mapCount.put(j, support);
			}else {
				// Second, set the count of i,j
				mapCount.put(j, support);
			}  
		}else {
			// First get the map of j
			Map<Integer, Integer> mapCount = matrix.get(j);
			if(mapCount == null) {
				mapCount = new HashMap<Integer,Integer>();
				matrix.put(j, mapCount);
				mapCount.put(i, support);
			}else {
				// Second, set the count of i,j
				mapCount.put(i, support);
			}  
		}
	}
}