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improve RepeatableSampler's inner PQ 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1437885 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Shai Erera 2013-01-24 08:15:45 +00:00
parent 956d884778
commit 80aa4db2f1
1 changed files with 18 additions and 29 deletions
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47
lucene/facet/src/java/org/apache/lucene/facet/search/sampling/RepeatableSampler.java
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@ -279,8 +279,13 @@ public class RepeatableSampler extends Sampler {
* into a bounded PQ (retains only sampleSize highest weights). * into a bounded PQ (retains only sampleSize highest weights).
*/ */
ScoredDocIDsIterator it = collection.iterator(); ScoredDocIDsIterator it = collection.iterator();
MI mi = null;
while (it.next()) { while (it.next()) {
pq.insertWithReuse((int)(it.getDocID() * PHI_32) & 0x7FFFFFFF); if (mi == null) {
mi = new MI();
}
mi.value = (int) (it.getDocID() * PHI_32) & 0x7FFFFFFF;
mi = pq.insertWithOverflow(mi);
} }
if (returnTimings) { if (returnTimings) {
times[1] = System.currentTimeMillis(); times[1] = System.currentTimeMillis();
@ -290,18 +295,26 @@ public class RepeatableSampler extends Sampler {
*/ */
Object[] heap = pq.getHeap(); Object[] heap = pq.getHeap();
for (int si = 0; si < sampleSize; si++) { for (int si = 0; si < sampleSize; si++) {
sample[si] = (int)(((IntPriorityQueue.MI)(heap[si+1])).value * PHI_32I) & 0x7FFFFFFF; sample[si] = (int)(((MI) heap[si+1]).value * PHI_32I) & 0x7FFFFFFF;
} }
if (returnTimings) { if (returnTimings) {
times[2] = System.currentTimeMillis(); times[2] = System.currentTimeMillis();
} }
} }
/**
* A mutable integer that lets queue objects be reused once they start overflowing.
*/
private static class MI {
MI() { }
public int value;
}
/** /**
* A bounded priority queue for Integers, to retain a specified number of * A bounded priority queue for Integers, to retain a specified number of
* the highest-weighted values for return as a random sample. * the highest-weighted values for return as a random sample.
*/ */
private static class IntPriorityQueue extends PriorityQueue<Object> { private static class IntPriorityQueue extends PriorityQueue<MI> {
/** /**
* Creates a bounded PQ of size <code>size</code>. * Creates a bounded PQ of size <code>size</code>.
@ -311,17 +324,6 @@ public class RepeatableSampler extends Sampler {
super(size); super(size);
} }
/**
* Inserts an integer with overflow and object reuse.
*/
public void insertWithReuse(int intval) {
if (this.mi == null) {
this.mi = new MI();
}
this.mi.value = intval;
this.mi = (MI)this.insertWithOverflow(this.mi);
}
/** /**
* Returns the underlying data structure for faster access. Extracting elements * Returns the underlying data structure for faster access. Extracting elements
* one at a time would require N logN time, and since we want the elements sorted * one at a time would require N logN time, and since we want the elements sorted
@ -338,23 +340,10 @@ public class RepeatableSampler extends Sampler {
* @return True if <code>o1</code> weighs less than <code>o2</code>. * @return True if <code>o1</code> weighs less than <code>o2</code>.
*/ */
@Override @Override
public boolean lessThan(Object o1, Object o2) { public boolean lessThan(MI o1, MI o2) {
return ((MI)o1).value < ((MI)o2).value; return o1.value < o2.value;
} }
/**
* A mutable integer that lets queue objects be reused once they start overflowing.
*/
private static class MI {
MI() { }
public int value;
}
/**
* The mutable integer instance for reuse after first overflow.
*/
private MI mi;
} }
/** /**