--- /dev/null
+package org.apache.lucene.search;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+
+final class SloppyPhraseScorer extends PhraseScorer {
+ private int slop;
+ private boolean checkedRepeats; // flag to only check in first candidate doc in case there are no repeats
+ private boolean hasRepeats; // flag indicating that there are repeats (already checked in first candidate doc)
+ private PhraseQueue pq; // for advancing min position
+ private PhrasePositions[] nrPps; // non repeating pps ordered by their query offset
+
+ SloppyPhraseScorer(Weight weight, PhraseQuery.PostingsAndFreq[] postings, Similarity similarity,
+ int slop, byte[] norms) {
+ super(weight, postings, similarity, norms);
+ this.slop = slop;
+ }
+
+ /**
+ * Score a candidate doc for all slop-valid position-combinations (matches)
+ * encountered while traversing/hopping the PhrasePositions.
+ * <br> The score contribution of a match depends on the distance:
+ * <br> - highest score for distance=0 (exact match).
+ * <br> - score gets lower as distance gets higher.
+ * <br>Example: for query "a b"~2, a document "x a b a y" can be scored twice:
+ * once for "a b" (distance=0), and once for "b a" (distance=2).
+ * <br>Possibly not all valid combinations are encountered, because for efficiency
+ * we always propagate the least PhrasePosition. This allows to base on
+ * PriorityQueue and move forward faster.
+ * As result, for example, document "a b c b a"
+ * would score differently for queries "a b c"~4 and "c b a"~4, although
+ * they really are equivalent.
+ * Similarly, for doc "a b c b a f g", query "c b"~2
+ * would get same score as "g f"~2, although "c b"~2 could be matched twice.
+ * We may want to fix this in the future (currently not, for performance reasons).
+ */
+ @Override
+ protected float phraseFreq() throws IOException {
+ int end = initPhrasePositions();
+ //printPositions(System.err, "INIT DONE:");
+ if (end==Integer.MIN_VALUE) {
+ return 0.0f;
+ }
+
+ float freq = 0.0f;
+ PhrasePositions pp = pq.pop();
+ int matchLength = end - pp.position;
+ int next = pq.size()>0 ? pq.top().position : pp.position;
+ //printQueue(System.err, pp, "Bef Loop: next="+next+" mlen="+end+"-"+pp.position+"="+matchLength);
+ while (pp.nextPosition() && (end=advanceRepeats(pp, end)) != Integer.MIN_VALUE) {
+ if (pp.position > next) {
+ //printQueue(System.err, pp, "A: >next="+next+" matchLength="+matchLength);
+ if (matchLength <= slop) {
+ freq += getSimilarity().sloppyFreq(matchLength); // score match
+ }
+ pq.add(pp);
+ pp = pq.pop();
+ next = pq.size()>0 ? pq.top().position : pp.position;
+ matchLength = end - pp.position;
+ //printQueue(System.err, pp, "B: >next="+next+" matchLength="+matchLength);
+ } else {
+ int matchLength2 = end - pp.position;
+ //printQueue(System.err, pp, "C: mlen2<mlen: next="+next+" matchLength="+matchLength+" matchLength2="+matchLength2);
+ if (matchLength2 < matchLength) {
+ matchLength = matchLength2;
+ }
+ }
+ }
+ if (matchLength <= slop) {
+ freq += getSimilarity().sloppyFreq(matchLength); // score match
+ }
+ return freq;
+ }
+
+ /**
+ * Advance repeating pps of an input (non-repeating) pp.
+ * Return a modified 'end' in case pp or its repeats exceeds original 'end'.
+ * "Dirty" trick: when there are repeats, modifies pp's position to that of
+ * least repeater of pp (needed when due to holes repeaters' positions are "back").
+ */
+ private int advanceRepeats(PhrasePositions pp, int end) throws IOException {
+ int repeatsEnd = end;
+ if (pp.position > repeatsEnd) {
+ repeatsEnd = pp.position;
+ }
+ if (!hasRepeats) {
+ return repeatsEnd;
+ }
+ int tpPos = tpPos(pp);
+ for (PhrasePositions pp2=pp.nextRepeating; pp2!=null; pp2=pp2.nextRepeating) {
+ while (tpPos(pp2) <= tpPos) {
+ if (!pp2.nextPosition()) {
+ return Integer.MIN_VALUE;
+ }
+ }
+ tpPos = tpPos(pp2);
+ if (pp2.position > repeatsEnd) {
+ repeatsEnd = pp2.position;
+ }
+ // "dirty" trick: with holes, given a pp, its repeating pp2 might have smaller position.
+ // so in order to have the right "start" in matchLength computation we fake pp.position.
+ // this relies on pp.nextPosition() not using pp.position.
+ if (pp2.position < pp.position) {
+ pp.position = pp2.position;
+ }
+ }
+ return repeatsEnd;
+ }
+
+ /**
+ * Initialize PhrasePositions in place.
+ * There is a one time initialization for this scorer (taking place at the first doc that matches all terms):
+ * <ul>
+ * <li>Detect groups of repeating pps: those with same tpPos (tpPos==position in the doc) but different offsets in query.
+ * <li>For each such group:
+ * <ul>
+ * <li>form an inner linked list of the repeating ones.
+ * <li>propagate all group members but first so that they land on different tpPos().
+ * </ul>
+ * <li>Mark whether there are repetitions at all, so that scoring queries with no repetitions has no overhead due to this computation.
+ * <li>Insert to pq only non repeating PPs, or PPs that are the first in a repeating group.
+ * </ul>
+ * Examples:
+ * <ol>
+ * <li>no repetitions: <b>"ho my"~2</b>
+ * <li>repetitions: <b>"ho my my"~2</b>
+ * <li>repetitions: <b>"my ho my"~2</b>
+ * </ol>
+ * @return end (max position), or Integer.MIN_VALUE if any term ran out (i.e. done)
+ */
+ private int initPhrasePositions() throws IOException {
+ int end = Integer.MIN_VALUE;
+
+ // no repeats at all (most common case is also the simplest one)
+ if (checkedRepeats && !hasRepeats) {
+ // build queue from list
+ pq.clear();
+ for (PhrasePositions pp=min,prev=null; prev!=max; pp=(prev=pp).next) { // iterate cyclic list: done once handled max
+ pp.firstPosition();
+ if (pp.position > end) {
+ end = pp.position;
+ }
+ pq.add(pp); // build pq from list
+ }
+ return end;
+ }
+
+ //printPositions(System.err, "Init: 1: Bef position");
+
+ // position the pp's
+ for (PhrasePositions pp=min,prev=null; prev!=max; pp=(prev=pp).next) { // iterate cyclic list: done once handled max
+ pp.firstPosition();
+ }
+
+ //printPositions(System.err, "Init: 2: Aft position");
+
+ // one time initialization for this scorer (done only for the first candidate doc)
+ if (!checkedRepeats) {
+ checkedRepeats = true;
+ ArrayList<PhrasePositions> ppsA = new ArrayList<PhrasePositions>();
+ PhrasePositions dummyPP = new PhrasePositions(null, -1, -1);
+ // check for repeats
+ for (PhrasePositions pp=min,prev=null; prev!=max; pp=(prev=pp).next) { // iterate cyclic list: done once handled max
+ if (pp.nextRepeating != null) {
+ continue; // a repetition of an earlier pp
+ }
+ ppsA.add(pp);
+ int tpPos = tpPos(pp);
+ for (PhrasePositions prevB=pp, pp2=pp.next; pp2!= min; pp2=pp2.next) {
+ if (
+ pp2.nextRepeating != null // already detected as a repetition of an earlier pp
+ || pp.offset == pp2.offset // not a repetition: the two PPs are originally in same offset in the query!
+ || tpPos(pp2) != tpPos) { // not a repetition
+ continue;
+ }
+ // a repetition
+ hasRepeats = true;
+ prevB.nextRepeating = pp2; // add pp2 to the repeats linked list
+ pp2.nextRepeating = dummyPP; // allows not to handle the last pp in a sub-list
+ prevB = pp2;
+ }
+ }
+ if (hasRepeats) {
+ // clean dummy markers
+ for (PhrasePositions pp=min,prev=null; prev!=max; pp=(prev=pp).next) { // iterate cyclic list: done once handled max
+ if (pp.nextRepeating == dummyPP) {
+ pp.nextRepeating = null;
+ }
+ }
+ }
+ nrPps = ppsA.toArray(new PhrasePositions[0]);
+ pq = new PhraseQueue(nrPps.length);
+ }
+
+ //printPositions(System.err, "Init: 3: Aft check-repeats");
+
+ // with repeats must advance some repeating pp's so they all start with differing tp's
+ if (hasRepeats) {
+ for (PhrasePositions pp: nrPps) {
+ if ((end=advanceRepeats(pp, end)) == Integer.MIN_VALUE) {
+ return Integer.MIN_VALUE; // ran out of a term -- done (no valid matches in current doc)
+ }
+ }
+ }
+
+ //printPositions(System.err, "Init: 4: Aft advance-repeats");
+
+ // build queue from non repeating pps
+ pq.clear();
+ for (PhrasePositions pp: nrPps) {
+ if (pp.position > end) {
+ end = pp.position;
+ }
+ pq.add(pp);
+ }
+
+ return end;
+ }
+
+ /** Actual position in doc of a PhrasePosition, relies on that position = tpPos - offset) */
+ private final int tpPos(PhrasePositions pp) {
+ return pp.position + pp.offset;
+ }
+
+// private void printPositions(PrintStream ps, String title) {
+// ps.println();
+// ps.println("---- "+title);
+// int k = 0;
+// if (nrPps!=null) {
+// for (PhrasePositions pp: nrPps) {
+// ps.println(" " + k++ + " " + pp);
+// }
+// } else {
+// for (PhrasePositions pp=min; 0==k || pp!=min; pp = pp.next) {
+// ps.println(" " + k++ + " " + pp);
+// }
+// }
+// }
+
+// private void printQueue(PrintStream ps, PhrasePositions ext, String title) {
+// ps.println();
+// ps.println("---- "+title);
+// ps.println("EXT: "+ext);
+// PhrasePositions[] t = new PhrasePositions[pq.size()];
+// if (pq.size()>0) {
+// t[0] = pq.pop();
+// ps.println(" " + 0 + " " + t[0]);
+// for (int i=1; i<t.length; i++) {
+// t[i] = pq.pop();
+// assert t[i-1].position <= t[i].position : "PQ is out of order: "+(i-1)+"::"+t[i-1]+" "+i+"::"+t[i];
+// ps.println(" " + i + " " + t[i]);
+// }
+// // add them back
+// for (int i=t.length-1; i>=0; i--) {
+// pq.add(t[i]);
+// }
+// }
+// }
+}
fnp / pylucene.git / blobdiff