/**
* Create a new bitmap for the s-step by doing a AND between this bitmap and the bitmap of an
* item.
*
* @param bitmapItem the bitmap of the item used for the S-Step
* @param sequencesSize the sequence lengths
* @param lastBitIndex the last bit index
* @param maxGap
* @return return the new bitmap
*/
Bitmap createNewBitmapSStep(
Bitmap bitmapItem, List<Integer> sequencesSize, int lastBitIndex, int maxGap) {
// INTERSECTION_COUNT++;
// create a new bitset that will be use for the new bitmap
BitSet newBitset = new BitSet(lastBitIndex);
// create the new bitmap
Bitmap newBitmap = new Bitmap(newBitset);
// We do an AND with the bitmap of the item and this bitmap
for (int bitK = bitmap.nextSetBit(0); bitK >= 0; bitK = bitmap.nextSetBit(bitK + 1)) {
// find the sid of this bit
int sid = bitToSID(bitK, sequencesSize);
// get the last bit for this sid
int lastBitOfSID = lastBitOfSID(sid, sequencesSize, lastBitIndex);
boolean match = false;
for (int bit = bitmapItem.bitmap.nextSetBit(bitK + 1);
bit >= 0 && bit <= lastBitOfSID && (bit - bitK <= maxGap);
bit = bitmapItem.bitmap.nextSetBit(bit + 1)) {
// new
int tid = bit - sequencesSize.get(sid);
newBitmap.bitmap.set(bit);
match = true;
// System.out.println();
// System.out.println("bit " + bit);
// System.out.println("sid " + sid);
// System.out.println("seqSize " + sequencesSize.get(sid));
// System.out.println("tid " + tid);
if (firstItemsetID == -1 || tid < firstItemsetID) {
firstItemsetID = tid;
}
}
if (match) {
// update the support
if (sid != newBitmap.lastSID) {
newBitmap.support++;
newBitmap.sidsum += sid;
}
newBitmap.lastSID = sid;
}
bitK = lastBitOfSID; // to skip the bit from the same sequence
}
// We return the resulting bitmap
return newBitmap;
}
/**
* Create a new bitmap by performing the I-STEP with this bitmap and the bitmap of an item.
*
* @param bitmapItem the bitmap of the item
* @param sequencesSize the sequence lengths
* @param lastBitIndex the last bit index
* @return the new bitmap
*/
Bitmap createNewBitmapIStep(Bitmap bitmapItem, List<Integer> sequencesSize, int lastBitIndex) {
// INTERSECTION_COUNT++;
// We create the new bitmap
BitSet newBitset = new BitSet(lastBitIndex); // TODO: USE LAST SET BIT
Bitmap newBitmap = new Bitmap(newBitset);
// We do an AND with the bitmap of the item
for (int bit = bitmap.nextSetBit(0); bit >= 0; bit = bitmap.nextSetBit(bit + 1)) {
if (bitmapItem.bitmap.get(bit)) { // if both bits are TRUE
// set the bit
newBitmap.bitmap.set(bit);
// update the support
int sid = bitToSID(bit, sequencesSize);
if (sid != newBitmap.lastSID) {
newBitmap.sidsum += sid;
newBitmap.support++;
}
newBitmap.lastSID = sid; // remember the last SID
// new
int tid = bit - sequencesSize.get(sid);
if (firstItemsetID == -1 || tid < firstItemsetID) {
firstItemsetID = tid;
}
// end new
}
}
// Then do the AND
newBitset.and(bitmapItem.bitmap);
// We return the resulting bitmap
return newBitmap;
}
