package ca.pfv.spmf.algorithms.frequentpatterns.uapriori;
/* 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/>.
*/
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
/**
* This class represents an itemset (a set of items)
* as used by the UApriori algorithm uncertain itemset mining.
*
* @see AlgoUApriori
* @see ItemUApriori
* @author Philippe Fournier-Viger
*/
public class ItemsetUApriori{
// an itemset is an ordered list of items
private List<ItemUApriori> items = new ArrayList<ItemUApriori>();
// the expected support
private double expectedsupport = 0;
/**
* Default constructor
*/
public ItemsetUApriori(){
}
/**
* Get the expected support of this itemset.
* @return expected support value.
*/
public double getExpectedSupport() {
return expectedsupport;
}
/**
* Get the expected support as a five decimals string
* @return a string
*/
public String getSupportAsString() {
DecimalFormat format = new DecimalFormat();
format.setMinimumFractionDigits(0);
format.setMaximumFractionDigits(5);
return format.format(expectedsupport);
}
/**
* Increase the expected support of this itemset by a given amount.
* @param supp the amount of support.
*/
void increaseSupportBy(double supp) {
expectedsupport += supp;
}
/**
* Add an item to that itemset
* @param value the item to be added
*/
void addItem(ItemUApriori value){
items.add(value);
}
/**
* Get items from that itemset.
* @return a list of integers (items).
*/
public List<ItemUApriori> getItems(){
return items;
}
/**
* Get the item at at a given position in that itemset
* @param index the position
* @return the item (Integer)
*/
public ItemUApriori get(int index){
return items.get(index);
}
/**
* print this itemset to System.out.
*/
public void print(){
System.out.print(toString());
}
/**
* Print the items in this itemset to System.out.
*/
public void printWithoutSupport(){
StringBuilder r = new StringBuilder ();
for(ItemUApriori attribute : items){
r.append(attribute.getId());
r.append(' ');
}
System.out.print(r);
}
/**
* Get a string representation of the items in this itemset.
*/
public String toString(){
StringBuilder r = new StringBuilder ();
for(ItemUApriori attribute : items){
r.append(attribute.toString());
r.append(' ');
}
return r.toString();
}
/**
* Check if this itemset contains a given item.
* @param item the item
* @return true, if yes, otherwise false.
*/
public boolean contains(ItemUApriori item) {
return items.contains(item);
}
/**
* Checks if this itemset is lexically smaller than a given itemset of the same size.
* @param itemset2 a given itemset
* @return true, if yes, otherwise, false
*/
boolean isLexicallySmallerthan(ItemsetUApriori itemset2){
// for each item in this itemset
for(int i=0; i< items.size(); i++){
// if it is larger than the item at the same position in itemset2
// return false
if(items.get(i).getId() > itemset2.items.get(i).getId()){
return false;
}
// if it is smaller than the item at the same position in itemset2
// return true
else if(items.get(i).getId() < itemset2.items.get(i).getId()){
return true;
}
}
// otherwise return true
return true;
}
/**
* Check if this itemset is equal to another one.
* @param itemset2 the other itemset
* @return true if yes, otherwise false
*/
public boolean isEqualTo(ItemsetUApriori itemset2){
// if not the same size, they can't be equal!
if(items.size() != itemset2.items.size()){
return false;
}
// for each item
for(ItemUApriori val : items){
// check if it is contained in the other itemset
// if not they are not equal.
if(!itemset2.contains(val)){
return false;
}
}
// they are equal, then return true
return true;
}
/**
* Set the expected support to a given value.
* @param expectedsupport the value
*/
void setExpectedSupport(double expectedsupport) {
this.expectedsupport = expectedsupport;
}
/**
* Make a copy of an itemset but exclude a given item
* @param itemToExclude the item
* @return the copy
*/
ItemsetUApriori cloneItemSetMinusOneItem(ItemUApriori itemToExclude){
// create a new itemset
ItemsetUApriori itemset = new ItemsetUApriori();
// for each item
for(ItemUApriori item : items){
// if it is not the one to be excluded, then add it
if(!item.equals(itemToExclude)){
itemset.addItem(item);
}
}
// return the itemset
return itemset;
}
/**
* Get the number of items in this itemset
* @return the item count (int)
*/
public int size(){
return items.size();
}
/**
* check if the item from this itemset are all the same as those of itemset2
* except the last item
* and that itemset2 is lexically smaller than this itemset. If all these conditions are satisfied,
* this method return the last item of itemset2. Otherwise it returns null.
* @return the last item of itemset2, or null.
* */
ItemUApriori allTheSameExceptLastItem(ItemsetUApriori itemset2) {
// if not the same size, then return null
if(itemset2.size() != items.size()){
return null;
}
for(int i=0; i< items.size(); i++){
// if they are the last items
if(i == items.size()-1){
// the one from items should be smaller (lexical order) and different than the one of itemset2
if(items.get(i).getId() >= itemset2.get(i).getId()){
return null;
}
}
// if they are not the last items, they should be different
else if(items.get(i).getId() != itemset2.get(i).getId()){
return null;
}
}
return itemset2.get(itemset2.size()-1);
}
/**
* Set the items in this itemsets.
* @param items a list of items.
*/
void setItems(List<ItemUApriori> items) {
this.items = items;
}
}