/**
* Actual call to SPAM algorithm. The output can be either kept or ignore. Whenever we choose to
* keep the patterns found, we can keep them in a file or in the main memory
*
* @param database Original database in where we want to search for the frequent patterns.
* @param keepPatterns Flag indicating if we want to keep the output or not
* @param verbose Flag for debugging purposes
* @param outputFilePath Path of the file in which we want to store the frequent patterns. If this
* value is null, we keep the patterns in the main memory. This argument is taken into account
* just when keepPatterns is activated.
* @throws IOException
*/
public void runAlgorithm(
SequenceDatabase database, boolean keepPatterns, boolean verbose, String outputFilePath)
throws IOException {
// If we do no have any file path
if (outputFilePath == null) {
// The user wants to save the results in memory
saver = new SaverIntoMemory();
} else {
// Otherwise, the user wants to save them in the given file
saver = new SaverIntoFile(outputFilePath);
}
this.minSupAbsolute = (int) Math.ceil(minSupRelative * database.size());
if (this.minSupAbsolute == 0) { // protection
this.minSupAbsolute = 1;
}
// reset the stats about memory usage
MemoryLogger.getInstance().reset();
// keeping the starting time
start = System.currentTimeMillis();
// We run SPAM algorithm
runSPAM(database, (long) minSupAbsolute, keepPatterns, verbose);
// keeping the ending time
end = System.currentTimeMillis();
// Search for frequent patterns: Finished
saver.finish();
}
/**
* Method to find all frequent items in a projected sequence database
*
* @param sequences the set of sequences
* @return A list of pairs, where a pair is an item with (1) a boolean indicating if it is in an
* itemset that is "cut" and (2) the sequence IDs where it occurs.
*/
protected Set<Pair> findAllFrequentPairs(
SequentialPattern prefix, List<PseudoSequence> sequences) {
// We use a Map the store the pairs.
Map<Pair, Pair> mapPairs = new HashMap<Pair, Pair>();
// for each sequence
for (PseudoSequence sequence : sequences) {
// for each itemset
for (int i = 0; i < sequence.size(); i++) {
// for each item
for (int j = 0; j < sequence.getSizeOfItemsetAt(i); j++) {
String item = sequence.getItemAtInItemsetAt(j, i);
// create the pair corresponding to this item
Pair paire = new Pair(sequence.isPostfix(i), item); // false is ok?
// get the pair object store in the map if there is one already
Pair oldPaire = mapPairs.get(paire);
// if there is no pair object yet
if (oldPaire == null) {
// store the pair object that we created
mapPairs.put(paire, paire);
} else {
// otherwise use the old one
paire = oldPaire;
}
// record the current sequence id for that pair
paire.getSequencesID().add(sequence.getId());
}
}
}
MemoryLogger.getInstance().checkMemory(); // check the memory for statistics.
// return the map of pairs
return mapPairs.keySet();
}
/** Print the statistics of the algorithm execution to System.out. */
public void printStatistics() {
StringBuilder r = new StringBuilder(200);
r.append("============= Algorithm VMSP - STATISTICS =============\n Total time ~ ");
r.append(endTime - startTime);
r.append(" ms\n");
r.append(" Frequent sequences count : " + patternCount);
r.append('\n');
r.append(" Max memory (mb) : ");
r.append(MemoryLogger.getInstance().getMaxMemory());
r.append(patternCount);
r.append('\n');
r.append("minsup " + minsup);
r.append('\n');
r.append("Intersection count " + Bitmap.INTERSECTION_COUNT + " \n");
r.append("===================================================\n");
// // PRINT PATTERNS
// System.out.println("PATTERNS FOUND ===============");
// for(Entry<Integer, List<Pattern>> entry : maxPatterns.entrySet()) {
// for(Pattern pat1: entry.getValue()) {
// System.out.println(pat1.prefix.toString());
//
// for(Entry<Integer, List<Pattern>> entry2 : maxPatterns.entrySet()) {
// for(Pattern pat2: entry2.getValue()) {
// if(pat1 != pat2 && strictlyContains(pat1.prefix, pat2.prefix)) {
// System.out.println("REDUNDANT : " + pat1.prefix + " " + pat2.prefix);
// }
//
// }
// }
// }
// }
System.out.println(r.toString());
}
/**
* Run the algorithm.
*
* @param k the value of k.
* @param minConfidence the minimum confidence threshold.
* @param database the database.
*/
public void runAlgorithm(int k, double minConfidence, Database database) {
// reset statistics
MemoryLogger.getInstance().reset(); // reset utility to check memory usage
maxCandidateCount = 0;
// save parameters
this.minConfidence = minConfidence;
this.database = database;
this.k = k;
// prepare internal variables and structures
this.minsuppRelative = 1;
tableItemTids = new BitSet[database.maxItem + 1]; // id item, count
tableItemCount = new int[database.maxItem + 1];
kRules = new PriorityQueue<RuleG>();
candidates = new RedBlackTree<RuleG>();
// record the start time
timeStart = System.currentTimeMillis();
// perform the first database scan to generate vertical database representation
scanDatabase(database);
// start the generation of rules
start();
// record the end time
timeEnd = System.currentTimeMillis();
}
/**
* Method to recursively grow a given sequential pattern.
*
* @param prefix the current sequential pattern that we want to try to grow
* @param database the current projected sequence database
* @throws IOException exception if there is an error writing to the output file
*/
private void recursion(SequentialPattern prefix, List<PseudoSequence> database)
throws IOException {
// find frequent items of size 1 in the current projected database.
Set<Pair> pairs = findAllFrequentPairs(prefix, database);
// For each pair found (a pair is an item with a boolean indicating if it
// appears in an itemset that is cut (a postfix) or not, and the sequence IDs
// where it appears in the projected database).
for (Pair pair : pairs) {
// if the item is frequent in the current projected database
if (pair.getCount() >= minsuppAbsolute) {
// create the new postfix by appending this item to the prefix
SequentialPattern newPrefix;
// if the item is part of a postfix
if (pair.isPostfix()) {
// we append it to the last itemset of the prefix
newPrefix = appendItemToPrefixOfSequence(prefix, pair.getItem());
} else { // else, we append it as a new itemset to the sequence
newPrefix = appendItemToSequence(prefix, pair.getItem());
}
// build the projected database with this item
List<PseudoSequence> projectedDB =
buildProjectedContext(pair.getItem(), database, pair.isPostfix());
newPrefix.setSequencesID(pair.getSequencesID());
// save the pattern
savePattern(newPrefix);
// make a recursive call
recursion(newPrefix, projectedDB);
}
}
MemoryLogger.getInstance().checkMemory();
}
/**
* Method to run the algorithm
*
* @param input path to an input file
* @param outputFilePath path for writing the output file
* @param minsupRel the minimum support as a relative value
* @throws IOException exception if error while writing the file or reading
*/
public List<TreeSet<PatternVMSP>> runAlgorithm(
String input, String outputFilePath, double minsupRel) throws IOException {
Bitmap.INTERSECTION_COUNT = 0;
// create an object to write the file
writer = new BufferedWriter(new FileWriter(outputFilePath));
// initialize the number of patterns found
patternCount = 0;
// to log the memory used
MemoryLogger.getInstance().reset();
// record start time
startTime = System.currentTimeMillis();
// RUN THE ALGORITHM
vmsp(input, minsupRel);
// record end time
endTime = System.currentTimeMillis();
// save result to the file
writeResultTofile(outputFilePath);
// close the file
writer.close();
// PRINT PATTTERNS FOUND
// for(TreeSet<Pattern> tree : maxPatterns) {
// if(tree == null) {
// continue;
// }
// for(Pattern pat : tree) {
//// System.out.println(" " + pat.prefix);
// }
// }
return maxPatterns;
}
/** Print statistics about the last algorithm execution to System.out. */
public void printStats() {
System.out.println("============= TRULEGROWTH - STATS =============");
// System.out.println("minsup: " + minsuppRelative);
System.out.println("Sequential rules count: " + ruleCount);
System.out.println("Total time : " + (timeEnd - timeStart) + " ms");
System.out.println("Max memory (mb)" + MemoryLogger.getInstance().getMaxMemory());
System.out.println("=====================================");
}
/** Print statistics about the last algorithm execution. */
public void printStats() {
System.out.println("============= TOP-K RULES - STATS =============");
System.out.println("Minsup : " + minsuppRelative);
System.out.println("Rules count: " + kRules.size());
System.out.println("Memory : " + MemoryLogger.getInstance().getMaxMemory() + " mb");
System.out.println("Total time : " + (timeEnd - timeStart) + " ms");
System.out.println("===================================================");
}
/** Print statistics about the algorithm execution to System.out. */
public void printStats() {
System.out.println("============= FP-GROWTH 0.96r14 - STATS =============");
long temps = endTime - startTimestamp;
System.out.println(" Transactions count from database : " + transactionCount);
System.out.print(" Max memory usage: " + MemoryLogger.getInstance().getMaxMemory() + " mb \n");
System.out.println(" Frequent itemsets count : " + itemsetCount);
System.out.println(" Total time ~ " + temps + " ms");
System.out.println("===================================================");
}
/** Print statistics about the algorithm execution to System.out. */
public void printStats() {
System.out.println("============= DECLAT vALTERNATE-Bitset v0.96r4- STATS =============");
long temps = endTime - startTimestamp;
System.out.println(" Transactions count from database : " + database.size());
System.out.println(" Frequent itemsets count : " + itemsetCount);
System.out.println(" Total time ~ " + temps + " ms");
System.out.println(
" Maximum memory usage : " + MemoryLogger.getInstance().getMaxMemory() + " mb");
System.out.println("===================================================");
}
/** Print statistics about the algorithm execution to System.out. */
public void printStats() {
System.out.println("============= APRIORI - STATS =============");
System.out.println(" Candidates count : " + totalCandidateCount);
System.out.println(
" The algorithm stopped at size " + (k - 1) + ", because there is no candidate");
System.out.println(" Frequent itemsets count : " + itemsetCount);
System.out.println(
" Maximum memory usage : " + MemoryLogger.getInstance().getMaxMemory() + " mb");
System.out.println(" Total time ~ " + (endTimestamp - startTimestamp) + " ms");
System.out.println("===================================================");
}
/**
* Register a given rule in the set of candidates for future expansions
*
* @param expandLR if true the rule will be considered for left/right expansions otherwise only
* right.
* @param rule the given rule
*/
private void registerAsCandidate(boolean expandLR, RuleG rule) {
// add the rule to candidates
rule.expandLR = expandLR;
candidates.add(rule);
// record the maximum number of candidates for statistics
if (candidates.size() >= maxCandidateCount) {
maxCandidateCount = candidates.size();
}
// check the memory usage
MemoryLogger.getInstance().checkMemory();
}
/**
* This is the recursive method to find all high utility itemsets. It writes the itemsets to the
* output file.
*
* @param prefix This is the current prefix. Initially, it is empty.
* @param pUL This is the Utility List of the prefix. Initially, it is empty.
* @param ULs The utility lists corresponding to each extension of the prefix.
* @param minUtility The minUtility threshold.
* @param prefixLength The current prefix length
* @throws IOException
*/
private void fhm(
int[] prefix, int prefixLength, UtilityList pUL, List<UtilityList> ULs, int minUtility)
throws IOException {
// For each extension X of prefix P
for (int i = 0; i < ULs.size(); i++) {
UtilityList X = ULs.get(i);
// If pX is a high utility itemset.
// we save the itemset: pX
if (X.sumIutils >= minUtility) {
// save to file
writeOut(prefix, prefixLength, X.item, X.sumIutils);
}
// If the sum of the remaining utilities for pX
// is higher than minUtility, we explore extensions of pX.
// (this is the pruning condition)
if (X.sumIutils + X.sumRutils >= minUtility) {
// This list will contain the utility lists of pX extensions.
List<UtilityList> exULs = new ArrayList<UtilityList>();
// For each extension of p appearing
// after X according to the ascending order
for (int j = i + 1; j < ULs.size(); j++) {
UtilityList Y = ULs.get(j);
// ======================== NEW OPTIMIZATION USED IN FHM
Map<Integer, Long> mapTWUF = mapFMAP.get(X.item);
if (mapTWUF != null) {
Long twuF = mapTWUF.get(Y.item);
if (twuF != null && twuF < minUtility) {
continue;
}
}
candidateCount++;
// =========================== END OF NEW OPTIMIZATION
// we construct the extension pXY
// and add it to the list of extensions of pX
UtilityList temp = construct(pUL, X, Y, minUtility);
if (temp != null) {
exULs.add(temp);
}
}
// We create new prefix pX
itemsetBuffer[prefixLength] = X.item;
// We make a recursive call to discover all itemsets with the prefix pXY
fhm(itemsetBuffer, prefixLength + 1, X, exULs, minUtility);
}
}
MemoryLogger.getInstance().checkMemory();
}
/**
* Print statistics about the algorithm execution to System.out.
*
* @param size the size of the database
*/
public void printStatistics(int size) {
StringBuffer r = new StringBuffer(200);
r.append("============= Algorithm BIDE2 - STATISTICS =============\n Total time ~ ");
r.append(endTime - startTime);
r.append(" ms\n");
r.append(" Closed sequential pattern count : ");
r.append(patternCount);
r.append('\n');
r.append(" Max memory (mb):");
r.append(MemoryLogger.getInstance().getMaxMemory());
r.append('\n');
r.append("===================================================\n");
System.out.println(r.toString());
}
/** Print statistics about the algorithm execution time */
public void printStatistics() {
StringBuilder r = new StringBuilder(200);
r.append("============= LAPIN - STATISTICS =============\n Total time ~ ");
r.append(endTime - startTime);
r.append(" ms\n");
r.append(" Frequent sequences count : " + patternCount);
r.append('\n');
r.append(" Max memory (mb) : ");
r.append(MemoryLogger.getInstance().getMaxMemory());
r.append(patternCount);
r.append('\n');
r.append("===================================================");
System.out.println(r.toString());
}
public String printStatistics() {
StringBuilder sb = new StringBuilder(200);
sb.append("============= Algorithm - STATISTICS =============\n Total time ~ ");
sb.append(getRunningTime());
sb.append(" ms\n");
sb.append(" Frequent sequences count : ");
sb.append(numberOfFrequentPatterns);
sb.append('\n');
sb.append(" Max memory (mb):");
sb.append(MemoryLogger.getInstance().getMaxMemory());
sb.append('\n');
sb.append(saver.print());
sb.append("\n===================================================\n");
return sb.toString();
}
/**
* Main method to run the algorithm
*
* @param input an input file path
* @param outputFilePath an output file path
* @param minsupRel the minimum support threshold as a percentage
* @throws IOException exception when writting result to a file
*/
public void runAlgorithm(String input, String outputFilePath, double minsupRel)
throws IOException {
this.input = input;
// prepare file writer for saving result to file
writer = new BufferedWriter(new FileWriter(outputFilePath));
patternCount = 0;
// reset tool to calculate max. memory usage
MemoryLogger.getInstance().reset();
startTime = System.currentTimeMillis();
// launch the algorithm!
lapin(input, minsupRel);
endTime = System.currentTimeMillis();
writer.close();
}
/** Print the statistics of the algorithm execution to System.out. */
public void printStatistics() {
StringBuilder r = new StringBuilder(200);
r.append("============= Algorithm - STATISTICS =============\n Total time ~ ");
r.append(endTime - startTime);
r.append(" ms\n");
r.append(" Frequent sequences count : " + patternCount);
r.append('\n');
r.append(" Max memory (mb) : ");
r.append(MemoryLogger.getInstance().getMaxMemory());
r.append(patternCount);
r.append('\n');
r.append("minsup " + minsup);
r.append('\n');
r.append("Intersection count " + Bitmap.INTERSECTION_COUNT + " \n");
r.append("===================================================\n");
System.out.println(r.toString());
}
/**
* Print statistics about the algorithm execution to System.out.
*
* @param size the size of the database
*/
public void printStatistics(int size) {
StringBuilder r = new StringBuilder(200);
r.append("============= Algorithm MaxSP - STATISTICS =============\n Total time ~ ");
r.append(endTime - startTime);
r.append(" ms\n");
r.append(" Maximal sequential pattern count : ");
r.append(patternCount);
r.append('\n');
r.append(" Max memory (mb):");
r.append(MemoryLogger.getInstance().getMaxMemory());
r.append('\n');
r.append("===================================================\n");
System.out.println(r.toString());
// System.out.println("Frequent pairs time : " + debugFrequentPairsTime);
// System.out.println("Generate ith period time: " + debugithPeriodTime);
// System.out.println("Add pair time: " + debugAddPairTime);
// System.out.println("Project DB time: " + debugProjectDBTime);
}
/**
* Run the algorithm
*
* @param database : a sequence database
* @param minsup : the minimum support as an integer
* @param outputFilePath : the path of the output file to save the result or null if you want the
* result to be saved into memory
* @return return the result, if saved into memory, otherwise null
* @throws IOException exception if error while writing the file
*/
public SequentialPatterns runAlgorithm(
SequenceDatabase database, String outputFilePath, int minsup) throws IOException {
// initialize variables for statistics
patternCount = 0;
MemoryLogger.getInstance().reset(); // to check the memory usage
// keep the minimum support because we will need it
this.minsuppAbsolute = minsup;
// save the start time
startTime = System.currentTimeMillis();
// run the algorithm
prefixSpan(database, outputFilePath);
// save the end time
endTime = System.currentTimeMillis();
// close the output file if the result was saved to a file
if (writer != null) {
writer.close();
}
return patterns;
}
/**
* Method to run the algorithm
*
* @param input path to an input file
* @param outputFilePath path for writing the output file
* @param minsupRel the minimum support as a relative value
* @param outputSequenceIdentifiers if true, sequence ids will be shown with each output pattern
* @throws IOException exception if error while writing the file or reading
*/
public void runAlgorithm(
String input, String outputFilePath, double minsupRel, boolean outputSequenceIdentifiers)
throws IOException {
this.outputSequenceIdentifiers = outputSequenceIdentifiers;
Bitmap.INTERSECTION_COUNT = 0;
// create an object to write the file
writer = new BufferedWriter(new FileWriter(outputFilePath));
// initialize the number of patterns found
patternCount = 0;
// to log the memory used
MemoryLogger.getInstance().reset();
// record start time
startTime = System.currentTimeMillis();
// RUN THE ALGORITHM
spam(input, minsupRel);
// record end time
endTime = System.currentTimeMillis();
// close the file
writer.close();
}
/**
* Print statistics about the latest execution to System.out.
*
* @throws IOException
*/
public void printStats() throws IOException {
System.out.println("============= FHM ALGORITHM v0.96r18 - STATS =============");
System.out.println(" Total time ~ " + (endTimestamp - startTimestamp) + " ms");
System.out.println(" Memory ~ " + MemoryLogger.getInstance().getMaxMemory() + " MB");
System.out.println(" High-utility itemsets count : " + huiCount);
System.out.println(" Candidate count : " + candidateCount);
if (DEBUG) {
int pairCount = 0;
double maxMemory = getObjectSize(mapFMAP);
for (Entry<Integer, Map<Integer, Long>> entry : mapFMAP.entrySet()) {
maxMemory += getObjectSize(entry.getKey());
for (Entry<Integer, Long> entry2 : entry.getValue().entrySet()) {
pairCount++;
maxMemory += getObjectSize(entry2.getKey()) + getObjectSize(entry2.getValue());
}
}
System.out.println("CMAP size " + maxMemory + " MB");
System.out.println("PAIR COUNT " + pairCount);
}
System.out.println("===================================================");
}
/**
* Run the algorithm
*
* @param database a sequence database
* @param outputPath an output file path
* @param minsup a minimum support as an integer representing a number of sequences
* @return return the result, if saved into memory, otherwise null
* @throws IOException exception if error while writing the file
*/
public SequentialPatterns runAlgorithm(SequenceDatabase database, String outputPath, int minsup)
throws IOException {
// save minsup
this.minsuppAbsolute = minsup;
// reset the counter for the number of patterns found
patternCount = 0;
// reset the stats about memory usage
MemoryLogger.getInstance().reset();
// save the start time
startTime = System.currentTimeMillis();
// start the algorithm
bide(database, outputPath);
// save the end time
endTime = System.currentTimeMillis();
// close the output file if the result was saved to a file
if (writer != null) {
writer.close();
}
return patterns;
}
/**
* Method to find all frequent items in a projected sequence database
*
* @param sequences the set of sequences
* @return A list of pairs, where a pair is an item with (1) booleans indicating if it is in an
* itemset that is "cut" at left or right (prefix or postfix) and (2) the sequence IDs where
* it occurs.
*/
protected Set<PairBIDE> findAllFrequentPairs(
SequentialPattern prefix, List<PseudoSequenceBIDE> sequences) {
// We use a Map the store the pairs.
Map<PairBIDE, PairBIDE> mapPairs = new HashMap<PairBIDE, PairBIDE>();
// for each sequence
for (PseudoSequenceBIDE sequence : sequences) {
// for each itemset
for (int i = 0; i < sequence.size(); i++) {
// for each item
for (int j = 0; j < sequence.getSizeOfItemsetAt(i); j++) {
Integer item = sequence.getItemAtInItemsetAt(j, i);
// create the pair corresponding to this item
PairBIDE pair = new PairBIDE(sequence.isCutAtRight(i), sequence.isPostfix(i), item);
// register this sequenceID for that pair.
addPairWithoutCheck(mapPairs, sequence.getId(), pair);
}
}
}
// check the memory usage
MemoryLogger.getInstance().checkMemory();
return mapPairs.keySet(); // return the pairs.
}
/**
* The actual method for extracting frequent sequences.
*
* @param database The original database
* @param minSupportAbsolute the absolute minimum support
* @param keepPatterns flag indicating if we are interested in keeping the output of the algorithm
* @param verbose Flag for debugging purposes
*/
protected void runSPAM(
SequenceDatabase database, long minSupportAbsolute, boolean keepPatterns, boolean verbose) {
// We get the equivalence classes formed by the frequent 1-patterns
frequentItems = database.frequentItems();
// We extract their patterns
Collection<Pattern> size1sequences = getPatterns(frequentItems);
// If we want to keep the output
if (keepPatterns) {
for (Pattern atom : size1sequences) {
// We keep all the frequent 1-patterns
saver.savePattern(atom);
}
}
database = null;
// We define the root class
EquivalenceClass rootClass = new EquivalenceClass(null);
/*And we insert the equivalence classes corresponding to the frequent
1-patterns as its members*/
for (EquivalenceClass atom : frequentItems) {
rootClass.addClassMember(atom);
}
// Inizialitation of the class that is in charge of find the frequent patterns
FrequentPatternEnumeration_SPAM frequentPatternEnumeration =
new FrequentPatternEnumeration_SPAM(minSupAbsolute, saver);
// We execute the search
frequentPatternEnumeration.execute(rootClass, keepPatterns, verbose);
// Once we had finished, we keep the number of frequent patterns that we found
numberOfFrequentPatterns = frequentPatternEnumeration.getFrequentPatterns();
// check the memory usage for statistics
MemoryLogger.getInstance().checkMemory();
}
/**
* Run the LAPIN algorithm
*
* @param input the input file path
* @param minsupRel the minsup threshold as a percentage
*/
private void lapin(String input, double minsupRel) throws IOException {
if (DEBUG) {
System.out.println(
"=== First database scan to count number of sequences and support of single items ===");
}
// FIRST DATABASE SCAN: SCAN THE DATABASE TO COUNT
// - THE NUMBER OF SEQUENCES
// - THE SUPPORT OF EACH SINGLE ITEM
// - THE LARGEST ITEM ID
int sequenceCount = 0;
int largestItemID = 0;
// This map will store for each item (key) the first position where the item appears in each
// sequence where it appears (value)
Map<Integer, List<Position>> mapItemFirstOccurrences = new HashMap<Integer, List<Position>>();
try {
// Read the input file
BufferedReader reader =
new BufferedReader(new InputStreamReader(new FileInputStream(new File(input))));
String thisLine;
// for each sequence of the input fiel
while ((thisLine = reader.readLine()) != null) {
// we use a set to remember which item have been seen already
Set<Integer> itemsAlreadySeen = new HashSet<Integer>();
// to know the itemset number
short itemsetID = 0;
// for each token in this line
for (String integer : thisLine.split(" ")) {
// if it is the end of an itemset
if ("-1".equals(integer)) {
itemsetID++;
} else if ("-2".equals(integer)) { // if it is the end of line
// nothing to do here
} else {
// otherwise, it is an item
Integer item = Integer.valueOf(integer);
// if this item was not seen already in that sequence
if (itemsAlreadySeen.contains(item) == false) {
// Get the list of positions of that item
List<Position> list = mapItemFirstOccurrences.get(item);
// if that list is null, create a new list
if (list == null) {
list = new ArrayList<Position>();
mapItemFirstOccurrences.put(item, list);
}
// Add the position of the item in that sequence to the list of first positions
// of that item
Position position = new Position(sequenceCount, itemsetID);
list.add(position);
// Remember that we have seen this item
itemsAlreadySeen.add(item);
// Check if the item is the largest item until now
if (item > largestItemID) {
largestItemID = item;
}
}
}
}
// Increase the count of sequences from the input file
sequenceCount++;
}
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
;
// Initialize the list of tables
tables = new Table[sequenceCount];
// Calculate absolute minimum support as a number of sequences
minsup = (int) Math.ceil(minsupRel * sequenceCount);
if (minsup == 0) {
minsup = 1;
}
if (DEBUG) {
System.out.println("Number of items: " + mapItemFirstOccurrences.size());
System.out.println("Sequence count: " + sequenceCount);
System.out.println("Abs. minsup: " + minsup + " sequences");
System.out.println("Rel. minsup: " + minsupRel + " %");
System.out.println("=== Determining the frequent items ===");
}
// // For each frequent item, save it and add it to the list of frequent items
List<Integer> frequentItems = new ArrayList<Integer>();
for (Entry<Integer, List<Position>> entry : mapItemFirstOccurrences.entrySet()) {
// Get the border created by this item
List<Position> itemBorder = entry.getValue();
// if the item is frequent
if (itemBorder.size() >= minsup) {
// Output the item and add it to the list of frequent items
Integer item = entry.getKey();
savePattern(item, itemBorder.size());
frequentItems.add(item);
if (DEBUG) {
System.out.println(" Item " + item + " is frequent with support = " + itemBorder.size());
}
}
}
if (DEBUG) {
System.out.println("=== Second database scan to construct item-is-exist tables ===");
}
// sort the frequent items (useful when generating 2-IE-sequences, later on).
Collections.sort(frequentItems);
// SECOND DATABASE SCAN:
// Now we will read the database again to create the Item-is-exist-table
// and SE-position-lists and count support of 2-IE-sequences
matrixPairCount = new SparseTriangularMatrix(largestItemID + 1);
// Initialise the IE position lists and SE position lists
sePositionList = new SEPositionList[sequenceCount];
iePositionList = new IEPositionList[sequenceCount];
try {
// Prepare to read the file
BufferedReader reader =
new BufferedReader(new InputStreamReader(new FileInputStream(new File(input))));
String thisLine;
// For each sequence in the file
int currentSequenceID = 0;
while ((thisLine = reader.readLine()) != null) {
// (1) ------- PARSE THE SEQUENCE BACKWARD TO CREATE THE ITEM-IS-EXIST TABLE FOR THATS
// SEQUENCE
// AND COUNT THE SUPPORT OF 2-IE-Sequences
// We will also use a structure to remember in which sequence we have seen each pair of
// items
// Note that in this structure, we will add +1 to the sid because by default the matrix is
// filled with 0
// and we don't want to think that the first sequence was already seen for all pairs.
AbstractTriangularMatrix matrixPairLastSeenInSID =
new SparseTriangularMatrix(largestItemID + 1);
// We count the number of positions (number of itemsets).
// To do that we count the number of "-" symbols in the file.
// We need to subtract 1 because the end of line "-2" contains "-".
int positionCount = -1;
for (char caracter : thisLine.toCharArray()) {
if (caracter == '-') {
positionCount++;
}
}
// Now we will scan the sequence again.
// This time we will remember which item were seen already
Set<Integer> itemsAlreadySeen = new HashSet<Integer>();
// During this scan, we will create the table for this sequence
Table table = new Table();
// To do that, we first create an initial position vector for that table
BitSet currentBitset = new BitSet(mapItemFirstOccurrences.size()); // OK ?
// This variable will be used to remember if a new item appeared in the current itemset
boolean seenNewItem = false;
// We will scan the sequence backward, starting from the end because
// we should not create a bit vector for all positions but for only
// the positions that are different from the previous one.
String[] tokens = thisLine.split(" ");
// This is the number of itemsets
int currentPosition = positionCount;
// to keep the current itemset in memory
List<Integer> currentItemset = new ArrayList<Integer>();
// For each token in that sequence
for (int i = tokens.length - 1; i >= 0; i--) {
// get the token
String token = tokens[i];
// if we reached the end of an itemset
if ("-1".equals(token)) {
// update the triangular matrix for counting 2-IE-sequences
// by comparing each pairs of items in the current itemset
for (int k = 0; k < currentItemset.size(); k++) {
Integer item1 = currentItemset.get(k);
for (int m = k + 1; m < currentItemset.size(); m++) {
Integer item2 = currentItemset.get(m);
// if that pair is frequent
int sid = matrixPairLastSeenInSID.getSupportForItems(item1, item2);
// and if we have not seen this sequence yet
if (sid != currentSequenceID + 1) {
// increment support count of this pair
matrixPairCount.incrementCount(item1, item2);
// remember that we have seen this pair so that we don't count it again
matrixPairLastSeenInSID.setSupport(item1, item2, currentSequenceID + 1);
}
}
}
currentItemset.clear();
// Decrease the current index of the position (itemset) in the sequence
currentPosition--;
// if the bit vector has changed since previous position, then
// we need to add a new bit vector to the table
if (seenNewItem) {
// create the position vector and add it to the item-is-exist table
PositionVector vector =
new PositionVector(currentPosition, (BitSet) currentBitset.clone());
table.add(vector);
}
} else if ("-2".equals(token)) { // if end of sequence, nothing to do
} else {
// otherwise, it is an item
Integer item = Integer.valueOf(token);
if (mapItemFirstOccurrences.get(item).size() >= minsup) { // only for frequent items
// if first time that we see this item
if (itemsAlreadySeen.contains(item) == false) {
// remember that we have seen a new item
seenNewItem = true;
// remember that we have seen this item
itemsAlreadySeen.add(item);
// add this item to the current bit vector
currentBitset.set(item);
}
// add this item to the current itemset
currentItemset.add(item);
}
}
}
// Lastly,
// update the triangular matrix for counting 2-IE-sequences one more time
// for the case where the pair is in first position of the sequence
// by considering each pair of items in the last itemset.
// This is done like it was done above, so I will not comment this part of the code again.
for (int k = 0; k < currentItemset.size(); k++) {
Integer item1 = currentItemset.get(k);
for (int m = k + 1; m < currentItemset.size(); m++) {
Integer item2 = currentItemset.get(m);
// if th
int sid = matrixPairLastSeenInSID.getSupportForItems(item1, item2);
if (sid != currentSequenceID + 1) {
matrixPairCount.incrementCount(item1, item2);
matrixPairLastSeenInSID.setSupport(item1, item2, currentSequenceID + 1);
}
}
}
// If a new item was seen
// Add an extra row to the item-is-exist table that will be called -1 with all items in
// this sequence
if (seenNewItem) {
PositionVector vector = new PositionVector(-1, (BitSet) currentBitset.clone());
table.add(vector);
}
//
//
// // Initialize the IE lists and SE lists for that sequence
// which will be filled with the next database scan.
sePositionList[currentSequenceID] = new SEPositionList(itemsAlreadySeen);
iePositionList[currentSequenceID] = new IEPositionList();
if (DEBUG) {
System.out.println("Table for sequence " + currentSequenceID + " : " + thisLine);
System.out.println(table.toString());
}
// put the current table in the array of item-is-exist-tables
tables[currentSequenceID] = table;
// we will process the next sequence id
currentSequenceID++;
}
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
// THIRD SCAN TO
// PARSE THE SEQUENCE FORWARD TO CREATE THE SE-POSITION LIST OF THAT SEQUENCE
// AND IEPositionList for frequent 2-IE-SEQUENCES
try {
BufferedReader reader =
new BufferedReader(new InputStreamReader(new FileInputStream(new File(input))));
String thisLine;
// For each sequence
int currentSequenceID = 0;
while ((thisLine = reader.readLine()) != null) {
// We will scan the sequence backward, starting from the end.
String[] tokens = thisLine.split(" ");
// to keep the current itemset in memory
List<Integer> currentItemset = new ArrayList<Integer>();
// this variable will be used to remember which itemset we are visiting
short itemsetID = 0;
// empty the object to track the current itemset (if it was used for the previous sequence)
currentItemset.clear();
// for each token of the current sequence
for (int i = 0; i < tokens.length; i++) {
String token = tokens[i];
// if we reached the end of an itemset
if ("-1".equals(token)) {
// if the current itemset contains more than one item
if (currentItemset.size() > 1) {
// update the position list for 2-IE-sequences
for (int k = 0; k < currentItemset.size(); k++) {
Integer item1 = currentItemset.get(k);
for (int m = k + 1; m < currentItemset.size(); m++) {
Integer item2 = currentItemset.get(m);
// if the pair is frequent
int support = matrixPairCount.getSupportForItems(item1, item2);
if (support >= minsup) {
iePositionList[currentSequenceID].register(item1, item2, itemsetID);
}
}
}
}
// increase itemsetID
itemsetID++;
// clear itemset
currentItemset.clear();
} else if ("-2".equals(token)) {
// if the end of a sequence, nothing special to do
} else {
// otherwise, the current token is an item
Integer item = Integer.valueOf(token);
// if the item is frequent
if (mapItemFirstOccurrences.get(item).size() >= minsup) {
// we add the current position to the item SE-position list
sePositionList[currentSequenceID].register(item, itemsetID);
// we add the item to the current itemset
currentItemset.add(item);
}
}
}
if (DEBUG) {
System.out.println("SE Position list for sequence " + currentSequenceID);
System.out.println(sePositionList[currentSequenceID]);
System.out.println("IE Position list for sequence " + currentSequenceID);
System.out.println(iePositionList[currentSequenceID]);
}
iePositionList[currentSequenceID].sort(); // sort the IE-position list
// update the sequence id for the next sequence
currentSequenceID++;
}
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
if (DEBUG) {
System.out.println("=== Starting sequential pattern generation ===");
}
// For each frequent item, call the recursive method to explore larger patterns
for (int i = 0; i < frequentItems.size(); i++) {
// Get the item
int item1 = frequentItems.get(i);
// Get the border for that item
List<Position> item1Border = mapItemFirstOccurrences.get(item1);
if (DEBUG) {
System.out.println("=== Considering item " + item1);
System.out.println(" Border of " + item1);
for (Position pos : item1Border) {
System.out.println(" seq: " + pos.sid + " itemset: " + pos.position);
}
}
// if the border contains at least minsup sequence (if the item is frequent)
if (item1Border.size() >= minsup) {
// Create an object prefix to represent the sequential pattern containing the item
Prefix prefix = new Prefix();
List<Integer> itemset = new ArrayList<Integer>(1);
itemset.add(item1);
prefix.itemsets.add(itemset);
// make a recursive call to find s-extensions of this prefix
genPatterns(
prefix,
item1Border,
frequentItems,
frequentItems,
item1,
true); // true, to disallow I-extension because we explore 2-IE sequences separately
}
// For each frequent 2-IE sequences stating with item1, we will explore 2-IE sequences
// by considering each frequent item larger than item1
for (int k = i + 1; k < frequentItems.size(); k++) {
// We consider item2
int item2 = frequentItems.get(k);
// Get the support of item1, item2
int support = matrixPairCount.getSupportForItems(item1, item2);
// if the pair {item1, item2} is frequent
if (support >= minsup) {
// get the list of position of item2
List<Position> item2Border = mapItemFirstOccurrences.get(item2);
// Create the border by using the 2-IE position list
List<Position> ie12Border = new ArrayList<Position>();
// We will loop over the border of item1 or item2 (the smallest one)
List<Position> borderToUse;
if (item2Border.size() < item1Border.size()) {
borderToUse = item2Border;
} else {
borderToUse = item1Border;
}
// For each sequence of the border that we consider
for (Position sequenceToUse : borderToUse) {
// Get the sequence id
int sid = sequenceToUse.sid;
// For this sequence, we will get the position list of each item
List<Short> listPosition1 = sePositionList[sid].getListForItem(item1);
List<Short> listPosition2 = sePositionList[sid].getListForItem(item2);
// if one of them is null, that means that both item1 and item2 do not appear in that
// sequence
// so we continue to the next sequence
if (listPosition1 == null || listPosition2 == null) {
continue;
}
// otherwise
// find the first common position of item1 and item2 in the sequence
int index1 = 0;
int index2 = 0;
// we do that by the following while loop
while (index1 < listPosition1.size() && index2 < listPosition2.size()) {
short position1 = listPosition1.get(index1);
short position2 = listPosition2.get(index2);
if (position1 < position2) {
index1++;
} else if (position1 > position2) {
index2++;
} else {
// we have found the position, so we add it to the new border and
// then stop because we do not want to add more than one position for
// the same sequence in the new border
ie12Border.add(new Position(sid, position1));
break;
}
}
}
if (DEBUG) {
System.out.println(
"=== Considering the 2-IE sequence {"
+ item1
+ ","
+ item2
+ "} with support "
+ support);
System.out.println(" Border of {" + item1 + "," + item2 + "}");
for (Position pos : ie12Border) {
System.out.println(" seq: " + pos.sid + " itemset: " + pos.position);
}
}
// finally, we create the prefix for the pattern {item1, item2}
Prefix prefix = new Prefix();
List<Integer> itemset = new ArrayList<Integer>(2);
itemset.add(item1);
itemset.add(item2);
prefix.itemsets.add(itemset);
// save the pattern
savePattern(prefix, support);
// perform recursive call to extend that pattern
genPatterns(
prefix,
ie12Border,
frequentItems,
frequentItems,
item2,
false); // false, to allow I-extension
}
}
}
// Record the maximum memory usage
MemoryLogger.getInstance().checkMemory();
writer.close();
}
/**
* This is the dfsPruning method as described in the SPAM paper.
*
* @param prefix the current prefix
* @param prefixBitmap the bitmap corresponding to the current prefix
* @param sn a list of items to be considered for i-steps
* @param in a list of items to be considered for s-steps
* @param hasToBeGreaterThanForIStep
* @param m size of the current prefix in terms of items
* @param lastAppendedItem the last appended item to the prefix
* @throws IOException if there is an error writing a pattern to the output file
* @return TRUE IF A FREQUENT PATTERN WAS CREATED USING THE PREFIX.
*/
boolean dfsPruning(
PrefixVMSP prefix,
Bitmap prefixBitmap,
List<Integer> sn,
List<Integer> in,
int hasToBeGreaterThanForIStep,
int m,
Integer lastAppendedItem)
throws IOException {
boolean atLeastOneFrequentExtension = false;
// System.out.println(prefix.toString());
// ====== S-STEPS ======
// Temporary variables (as described in the paper)
List<Integer> sTemp = new ArrayList<Integer>();
List<Bitmap> sTempBitmaps = new ArrayList<Bitmap>();
// for CMAP pruning, we will only check against the last appended item
Map<Integer, Integer> mapSupportItemsAfter = coocMapAfter.get(lastAppendedItem);
// for each item in sn
loopi:
for (Integer i : sn) {
// LAST POSITION PRUNING
/*if (useLastPositionPruning && lastItemPositionMap.get(i) < prefixBitmap.firstItemsetID) {
// System.out.println("TEST");
continue loopi;
}*/
// CMAP PRUNING
// we only check with the last appended item
if (useCMAPPruning) {
if (mapSupportItemsAfter == null) {
continue loopi;
}
Integer support = mapSupportItemsAfter.get(i);
if (support == null || support < minsup) {
// System.out.println("PRUNE");
continue loopi;
}
}
// perform the S-STEP with that item to get a new bitmap
Bitmap.INTERSECTION_COUNT++;
Bitmap newBitmap =
prefixBitmap.createNewBitmapSStep(verticalDB.get(i), sequencesSize, lastBitIndex, maxGap);
// if the support is higher than minsup
if (newBitmap.getSupportWithoutGapTotal() >= minsup) {
// record that item and pattern in temporary variables
sTemp.add(i);
sTempBitmaps.add(newBitmap);
}
}
// for each pattern recorded for the s-step
for (int k = 0; k < sTemp.size(); k++) {
// STRATEGY: NEWWW
atLeastOneFrequentExtension = true;
int item = sTemp.get(k);
// create the new prefix
PrefixVMSP prefixSStep = prefix.cloneSequence();
prefixSStep.addItemset(new Itemset(item));
if (item % 2 == 0) {
prefixSStep.sumOfEvenItems = item + prefix.sumOfEvenItems;
prefixSStep.sumOfOddItems = prefix.sumOfOddItems;
} else {
prefixSStep.sumOfEvenItems = prefix.sumOfEvenItems;
prefixSStep.sumOfOddItems = item + prefix.sumOfOddItems;
}
// prefixSStep.sumOfItems = item + prefix.sumOfItems;
// create the new bitmap
Bitmap newBitmap = sTempBitmaps.get(k);
// save the pattern to the file
if (newBitmap.getSupport() >= minsup) {
boolean hasFrequentExtension = false;
// recursively try to extend that pattern
if (maximumPatternLength > m) {
hasFrequentExtension =
dfsPruning(prefixSStep, newBitmap, sTemp, sTemp, item, m + 1, item);
}
if (hasFrequentExtension == false) {
savePatternMultipleItems(prefixSStep, newBitmap, m);
}
}
}
Map<Integer, Integer> mapSupportItemsEquals = coocMapEquals.get(lastAppendedItem);
// ======== I STEPS =======
// Temporary variables
List<Integer> iTemp = new ArrayList<Integer>();
List<Bitmap> iTempBitmaps = new ArrayList<Bitmap>();
// for each item in in
loop2:
for (Integer i : in) {
// the item has to be greater than the largest item
// already in the last itemset of prefix.
if (i > hasToBeGreaterThanForIStep) {
// LAST POSITION PRUNING
/*if (useLastPositionPruning && lastItemPositionMap.get(i) < prefixBitmap.firstItemsetID) {
continue loop2;
}*/
// CMAP PRUNING
if (useCMAPPruning) {
if (mapSupportItemsEquals == null) {
continue loop2;
}
Integer support = mapSupportItemsEquals.get(i);
if (support == null || support < minsup) {
continue loop2;
}
}
// Perform an i-step with this item and the current prefix.
// This creates a new bitmap
Bitmap.INTERSECTION_COUNT++;
Bitmap newBitmap =
prefixBitmap.createNewBitmapIStep(verticalDB.get(i), sequencesSize, lastBitIndex);
// If the support is no less than minsup
if (newBitmap.getSupport() >= minsup) {
// record that item and pattern in temporary variables
iTemp.add(i);
iTempBitmaps.add(newBitmap);
}
}
}
// for each pattern recorded for the i-step
for (int k = 0; k < iTemp.size(); k++) { // STRATEGY: NEWWW
atLeastOneFrequentExtension = true;
int item = iTemp.get(k);
// create the new prefix
PrefixVMSP prefixIStep = prefix.cloneSequence();
prefixIStep.getItemsets().get(prefixIStep.size() - 1).addItem(item);
if (item % 2 == 0) {
prefixIStep.sumOfEvenItems = item + prefix.sumOfEvenItems;
prefixIStep.sumOfOddItems = prefix.sumOfOddItems;
} else {
prefixIStep.sumOfEvenItems = prefix.sumOfEvenItems;
prefixIStep.sumOfOddItems = item + prefix.sumOfOddItems;
}
// create the new bitmap
Bitmap newBitmap = iTempBitmaps.get(k);
// recursively try to extend that pattern
boolean hasFrequentExtension = false;
if (maximumPatternLength > m) {
hasFrequentExtension = dfsPruning(prefixIStep, newBitmap, sTemp, iTemp, item, m + 1, item);
}
if (hasFrequentExtension == false) {
// save the pattern
savePatternMultipleItems(prefixIStep, newBitmap, m);
}
}
// check the memory usage
MemoryLogger.getInstance().checkMemory();
return atLeastOneFrequentExtension || useStrategyForwardExtensionChecking == false;
}
/**
* Run the algorithm
*
* @param input the input file path
* @param output the output file path
* @param minUtility the minimum utility threshold
* @throws IOException exception if error while writing the file
*/
public void runAlgorithm(String input, String output, int minUtility) throws IOException {
// reset maximum
MemoryLogger.getInstance().reset();
// initialize the buffer for storing the current itemset
itemsetBuffer = new int[BUFFERS_SIZE];
mapFMAP = new HashMap<Integer, Map<Integer, Long>>();
startTimestamp = System.currentTimeMillis();
writer = new BufferedWriter(new FileWriter(output));
// We create a map to store the TWU of each item
mapItemToTWU = new HashMap<Integer, Long>();
// We scan the database a first time to calculate the TWU of each item.
BufferedReader myInput = null;
String thisLine;
try {
// prepare the object for reading the file
myInput = new BufferedReader(new InputStreamReader(new FileInputStream(new File(input))));
// for each line (transaction) until the end of file
while ((thisLine = myInput.readLine()) != null) {
// if the line is a comment, is empty or is a
// kind of metadata
if (thisLine.isEmpty() == true
|| thisLine.charAt(0) == '#'
|| thisLine.charAt(0) == '%'
|| thisLine.charAt(0) == '@') {
continue;
}
// split the transaction according to the : separator
String split[] = thisLine.split(":");
// the first part is the list of items
String items[] = split[0].split(" ");
// the second part is the transaction utility
int transactionUtility = Integer.parseInt(split[1]);
// for each item, we add the transaction utility to its TWU
for (int i = 0; i < items.length; i++) {
// convert item to integer
Integer item = Integer.parseInt(items[i]);
// get the current TWU of that item
Long twu = mapItemToTWU.get(item);
// add the utility of the item in the current transaction to its twu
twu = (twu == null) ? transactionUtility : twu + transactionUtility;
mapItemToTWU.put(item, twu);
}
}
} catch (Exception e) {
// catches exception if error while reading the input file
e.printStackTrace();
} finally {
if (myInput != null) {
myInput.close();
}
}
// CREATE A LIST TO STORE THE UTILITY LIST OF ITEMS WITH TWU >= MIN_UTILITY.
List<UtilityList> listOfUtilityLists = new ArrayList<UtilityList>();
// CREATE A MAP TO STORE THE UTILITY LIST FOR EACH ITEM.
// Key : item Value : utility list associated to that item
Map<Integer, UtilityList> mapItemToUtilityList = new HashMap<Integer, UtilityList>();
// For each item
for (Integer item : mapItemToTWU.keySet()) {
// if the item is promising (TWU >= minutility)
if (mapItemToTWU.get(item) >= minUtility) {
// create an empty Utility List that we will fill later.
UtilityList uList = new UtilityList(item);
mapItemToUtilityList.put(item, uList);
// add the item to the list of high TWU items
listOfUtilityLists.add(uList);
}
}
// SORT THE LIST OF HIGH TWU ITEMS IN ASCENDING ORDER
Collections.sort(
listOfUtilityLists,
new Comparator<UtilityList>() {
public int compare(UtilityList o1, UtilityList o2) {
// compare the TWU of the items
return compareItems(o1.item, o2.item);
}
});
// SECOND DATABASE PASS TO CONSTRUCT THE UTILITY LISTS
// OF 1-ITEMSETS HAVING TWU >= minutil (promising items)
try {
// prepare object for reading the file
myInput = new BufferedReader(new InputStreamReader(new FileInputStream(new File(input))));
// variable to count the number of transaction
int tid = 0;
// for each line (transaction) until the end of file
while ((thisLine = myInput.readLine()) != null) {
// if the line is a comment, is empty or is a
// kind of metadata
if (thisLine.isEmpty() == true
|| thisLine.charAt(0) == '#'
|| thisLine.charAt(0) == '%'
|| thisLine.charAt(0) == '@') {
continue;
}
// split the line according to the separator
String split[] = thisLine.split(":");
// get the list of items
String items[] = split[0].split(" ");
// get the list of utility values corresponding to each item
// for that transaction
String utilityValues[] = split[2].split(" ");
// Copy the transaction into lists but
// without items with TWU < minutility
int remainingUtility = 0;
long newTWU = 0; // NEW OPTIMIZATION
// Create a list to store items
List<Pair> revisedTransaction = new ArrayList<Pair>();
// for each item
for (int i = 0; i < items.length; i++) {
/// convert values to integers
Pair pair = new Pair();
pair.item = Integer.parseInt(items[i]);
pair.utility = Integer.parseInt(utilityValues[i]);
// if the item has enough utility
if (mapItemToTWU.get(pair.item) >= minUtility) {
// add it
revisedTransaction.add(pair);
remainingUtility += pair.utility;
newTWU += pair.utility; // NEW OPTIMIZATION
}
}
// sort the transaction
Collections.sort(
revisedTransaction,
new Comparator<Pair>() {
public int compare(Pair o1, Pair o2) {
return compareItems(o1.item, o2.item);
}
});
// for each item left in the transaction
for (int i = 0; i < revisedTransaction.size(); i++) {
Pair pair = revisedTransaction.get(i);
// int remain = remainingUtility; // FOR OPTIMIZATION
// subtract the utility of this item from the remaining utility
remainingUtility = remainingUtility - pair.utility;
// get the utility list of this item
UtilityList utilityListOfItem = mapItemToUtilityList.get(pair.item);
// Add a new Element to the utility list of this item corresponding to this transaction
Element element = new Element(tid, pair.utility, remainingUtility);
utilityListOfItem.addElement(element);
// BEGIN NEW OPTIMIZATION for FHM
Map<Integer, Long> mapFMAPItem = mapFMAP.get(pair.item);
if (mapFMAPItem == null) {
mapFMAPItem = new HashMap<Integer, Long>();
mapFMAP.put(pair.item, mapFMAPItem);
}
for (int j = i + 1; j < revisedTransaction.size(); j++) {
Pair pairAfter = revisedTransaction.get(j);
Long twuSum = mapFMAPItem.get(pairAfter.item);
if (twuSum == null) {
mapFMAPItem.put(pairAfter.item, newTWU);
} else {
mapFMAPItem.put(pairAfter.item, twuSum + newTWU);
}
}
// END OPTIMIZATION of FHM
}
tid++; // increase tid number for next transaction
}
} catch (Exception e) {
// to catch error while reading the input file
e.printStackTrace();
} finally {
if (myInput != null) {
myInput.close();
}
}
// check the memory usage
MemoryLogger.getInstance().checkMemory();
// Mine the database recursively
fhm(itemsetBuffer, 0, null, listOfUtilityLists, minUtility);
// check the memory usage again and close the file.
MemoryLogger.getInstance().checkMemory();
// close output file
writer.close();
// record end time
endTimestamp = System.currentTimeMillis();
}
/**
* This is the main method for the BIDE+ algorithm.
*
* @param database a sequence database
* @throws IOException exception if some error occurs while writing the output file.
*/
private void bide(SequenceDatabase database, String outputFilePath) throws IOException {
// if the user want to keep the result into memory
if (outputFilePath == null) {
writer = null;
patterns = new SequentialPatterns("FREQUENT SEQUENTIAL PATTERNS");
} else { // if the user want to save the result to a file
patterns = null;
writer = new BufferedWriter(new FileWriter(outputFilePath));
}
// The algorithm first scan the database to find all frequent items
// The algorithm note the sequences in which these items appear.
// This is stored in a map: Key: item Value : IDs of sequences containing the item
Map<Integer, Set<Integer>> mapSequenceID = findSequencesContainingItems(database);
// WE CONVERT THE DATABASE TO A PSEUDO-DATABASE, AND REMOVE
// THE ITEMS OF SIZE 1 THAT ARE NOT FREQUENT, SO THAT THE ALGORITHM
// WILL NOT CONSIDER THEM ANYMORE.
// OPTIMIZATION Create COOC MAP
// coocMapBefore = new HashMap<Integer, Map<Integer,
// Integer>>(mapSequenceID.entrySet().size());
// we create a database
initialDatabase = new ArrayList<PseudoSequenceBIDE>();
// for each sequence of the original database
for (Sequence sequence : database.getSequences()) {
// we make a copy of the sequence while removing infrequent items
Sequence optimizedSequence = sequence.cloneSequenceMinusItems(mapSequenceID, minsuppAbsolute);
if (optimizedSequence.size() != 0) {
// if this sequence has size >0, we add it to the new database
initialDatabase.add(new PseudoSequenceBIDE(optimizedSequence, 0, 0));
}
// // update COOC map
// HashSet<Integer> alreadySeen = new HashSet<Integer>();
// for(List<Integer> itemset : optimizedSequence.getItemsets()) {
// for(Integer item : itemset) {
// Map<Integer, Integer> mapCoocItem = coocMapBefore.get(item);
// if(mapCoocItem == null) {
// mapCoocItem = new HashMap<Integer, Integer>();
// coocMapBefore.put(item, mapCoocItem);
// }
// for(Integer itemSeen : alreadySeen) {
// if(itemSeen != item) {
// Integer frequency = mapCoocItem.get(itemSeen);
// if(frequency == null) {
// mapCoocItem.put(itemSeen, 1);
// }else {
// mapCoocItem.put(itemSeen, frequency+1);
// }
// }
// }
// alreadySeen.add(item);
// }
// }
}
// For each frequent item
loop1:
for (Entry<Integer, Set<Integer>> entry : mapSequenceID.entrySet()) {
// if the item is frequent
if (entry.getValue().size() >= minsuppAbsolute) {
// Map<Integer, Integer> mapCoocItem = coocMapBefore.get(entry.getKey());
// if(mapCoocItem != null) {
// for(Integer supportCoocBefore : mapCoocItem.values()) {
// if(supportCoocBefore >= entry.getValue().size()) {
// continue loop1;
// }
// }
// }
// build the projected database with this item
Integer item = entry.getKey();
List<PseudoSequenceBIDE> projectedContext =
buildProjectedContextSingleItem(item, initialDatabase, false, entry.getValue());
// Create the prefix with this item
SequentialPattern prefix = new SequentialPattern();
prefix.addItemset(new Itemset(item));
// set the sequence IDS of this prefix
prefix.setSequenceIDs(entry.getValue());
// variable to store the largest support of patterns
// that will be found starting with this prefix
if (projectedContext.size() >= minsuppAbsolute) {
int successorSupport = 0;
if (!checkBackScanPruning(prefix, entry.getValue())) {
successorSupport = recursion(prefix, projectedContext); // récursion;
}
// Finally, because this prefix has support > minsup
// and passed the backscan pruning,
// we check if it has no sucessor with support >= minsup
// (a forward extension)
// IF no forward extension
if (successorSupport != entry.getValue().size()) { // ######### MODIFICATION ####
// IF there is also no backward extension
if (!checkBackwardExtension(prefix, entry.getValue())) {
// the pattern is closed and we save it
savePattern(prefix);
}
}
} else {
if (!checkBackwardExtension(prefix, entry.getValue())) {
// the pattern is closed and we save it
savePattern(prefix);
}
}
}
}
// check the memory usage for statistics
MemoryLogger.getInstance().checkMemory();
}
/**
* The main recursive method of LAPIN
*
* @param prefix the current prefix
* @param prefix the prefix
* @param prefixBorder a list of position that is the prefix border
* @param in items that could be appended by i-extension
* @param sn items that could be appended by s-extension
* @param hasToBeGreaterThanForIStep
* @throws IOException if error while writing to file
*/
private void genPatterns(
Prefix prefix,
List<Position> prefixBorder,
List<Integer> sn,
List<Integer> in,
int hasToBeGreaterThanForIStep,
boolean doNotPerformIExtensions)
throws IOException {
// if(DEBUG) {
// if(seqDB == null) {
// seqDB = new SequenceDatabase();
// seqDB.loadFile(input);
// }
// // FOR DEBUGGING = WORK ONLY FOR SEQUENCE WITH SINGLE ITEMS IN EACH ITEMSET
// System.out.println("Checking if the border of " + prefix + " is correct");
// for(Position pos : prefixBorder) {
// int sid = pos.sid;
// Sequence seq = seqDB.getSequences().get(sid);
// int calculatedPosition = 0;
//
// int prefixItemsetID =0;
// for(; calculatedPosition< seq.size(); calculatedPosition++ ) {
// Integer[] itemset = seq.get(calculatedPosition);
// Integer itemToMatch = prefix.itemsets.get(prefixItemsetID).get(0);
// if(itemset[0].equals(itemToMatch)) {
// prefixItemsetID++;
// if(prefixItemsetID == prefix.size()) {
// if(pos.position != calculatedPosition) {
// System.out.println("THE BORDER IS WRONG FOR PREFIX " + prefix + " AND SEQUENCE :" +
// sid + " " + seq);
// System.out.println();
// }else {
// System.out.println("THE BORDER IS OK");
// break;
// }
// }
// }
// }
// }
//// }
// ====== S-STEPS ======
// // Temporary variables (as described in the paper)
List<Integer> sTemp = new ArrayList<Integer>();
List<Integer> sTempSupport = new ArrayList<Integer>();
//
// // for each item in sn
for (Integer item : sn) {
// perform the S-STEP
int support = calculateSupportSStep(item, prefixBorder);
// if the support is higher than minsup
if (support >= minsup) {
// // record that item and pattern in temporary variables
sTemp.add(item);
sTempSupport.add(support);
}
}
// for each pattern recorded for the s-step
for (int k = 0; k < sTemp.size(); k++) {
int item = sTemp.get(k);
// create the new prefix
Prefix prefixSStep = prefix.cloneSequence();
List<Integer> itemset = new ArrayList<Integer>(1);
itemset.add(item);
prefixSStep.itemsets.add(itemset);
// save the pattern to the file
savePattern(prefixSStep, sTempSupport.get(k));
// recursively try to extend that pattern
List<Position> newBorder = recalculateBorderForSExtension(prefixBorder, item);
// Recursive call
genPatterns(prefixSStep, newBorder, sTemp, sTemp, item, false);
}
if (doNotPerformIExtensions) {
return;
}
// ======== I STEPS =======
// Temporary variables
List<Integer> iTemp = new ArrayList<Integer>();
List<List<Position>> iTempBorder = new ArrayList<List<Position>>();
//
// // for each item in in
// the item has to be greater than the largest item
// already in the last itemset of prefix.
int index = Collections.binarySearch(in, hasToBeGreaterThanForIStep);
for (int i = index; i < in.size(); i++) {
Integer item = in.get(i);
List<Integer> lastItemset = prefix.itemsets.get(prefix.itemsets.size() - 1);
// Integer lastItem = lastItemset.get(lastItemset.size()-1);
boolean willAddSecondItem = lastItemset.size() == 1;
// AN OPTIMIZATION
// perform the I-STEP
int support = estimateSupportIStep(item, prefixBorder);
// if the estimated support is higher than minsup
if (support >= minsup) {
// recalculate the border
// in this case, the method takes the prefix border as input
List<Position> newBorder =
recalculateBorderForIExtension(
lastItemset, prefixBorder, hasToBeGreaterThanForIStep, item, willAddSecondItem);
// record that item and pattern in temporary variables
if (newBorder.size() >= minsup) {
iTemp.add(item);
iTempBorder.add(newBorder);
}
}
}
// for each pattern recorded for the i-step
for (int k = 0; k < iTemp.size(); k++) {
int item = iTemp.get(k);
// create the new prefix
Prefix prefixIStep = prefix.cloneSequence();
prefixIStep.itemsets.get(prefixIStep.size() - 1).add(item);
// save the pattern
List<Position> newBorder = iTempBorder.get(k);
savePattern(prefixIStep, newBorder.size());
// recursively try to extend that pattern
genPatterns(prefixIStep, newBorder, sTemp, iTemp, item, false);
}
// check the memory usage
MemoryLogger.getInstance().checkMemory();
}