Examples with Result org.apache.lucene.util.fst.Util.Result used on opensource projects

Example 1 with Result

use of org.apache.lucene.util.fst.Util.Result in project lucene-solr by apache.

the class FreeTextSuggester method lookup.

/** Retrieve suggestions. */
public List<LookupResult> lookup(final CharSequence key, Set<BytesRef> contexts, int num) throws IOException {
    if (contexts != null) {
        throw new IllegalArgumentException("this suggester doesn't support contexts");
    }
    if (fst == null) {
        throw new IllegalStateException("Lookup not supported at this time");
    }
    try (TokenStream ts = queryAnalyzer.tokenStream("", key.toString())) {
        TermToBytesRefAttribute termBytesAtt = ts.addAttribute(TermToBytesRefAttribute.class);
        OffsetAttribute offsetAtt = ts.addAttribute(OffsetAttribute.class);
        PositionLengthAttribute posLenAtt = ts.addAttribute(PositionLengthAttribute.class);
        PositionIncrementAttribute posIncAtt = ts.addAttribute(PositionIncrementAttribute.class);
        ts.reset();
        BytesRefBuilder[] lastTokens = new BytesRefBuilder[grams];
        //System.out.println("lookup: key='" + key + "'");
        // Run full analysis, but save only the
        // last 1gram, last 2gram, etc.:
        int maxEndOffset = -1;
        boolean sawRealToken = false;
        while (ts.incrementToken()) {
            BytesRef tokenBytes = termBytesAtt.getBytesRef();
            sawRealToken |= tokenBytes.length > 0;
            // TODO: this is somewhat iffy; today, ShingleFilter
            // sets posLen to the gram count; maybe we should make
            // a separate dedicated att for this?
            int gramCount = posLenAtt.getPositionLength();
            assert gramCount <= grams;
            // Safety: make sure the recalculated count "agrees":
            if (countGrams(tokenBytes) != gramCount) {
                throw new IllegalArgumentException("tokens must not contain separator byte; got token=" + tokenBytes + " but gramCount=" + gramCount + " does not match recalculated count=" + countGrams(tokenBytes));
            }
            maxEndOffset = Math.max(maxEndOffset, offsetAtt.endOffset());
            BytesRefBuilder b = new BytesRefBuilder();
            b.append(tokenBytes);
            lastTokens[gramCount - 1] = b;
        }
        ts.end();
        if (!sawRealToken) {
            throw new IllegalArgumentException("no tokens produced by analyzer, or the only tokens were empty strings");
        }
        // Carefully fill last tokens with _ tokens;
        // ShingleFilter appraently won't emit "only hole"
        // tokens:
        int endPosInc = posIncAtt.getPositionIncrement();
        // Note this will also be true if input is the empty
        // string (in which case we saw no tokens and
        // maxEndOffset is still -1), which in fact works out OK
        // because we fill the unigram with an empty BytesRef
        // below:
        boolean lastTokenEnded = offsetAtt.endOffset() > maxEndOffset || endPosInc > 0;
        if (lastTokenEnded) {
            // starting with "foo":
            for (int i = grams - 1; i > 0; i--) {
                BytesRefBuilder token = lastTokens[i - 1];
                if (token == null) {
                    continue;
                }
                token.append(separator);
                lastTokens[i] = token;
            }
            lastTokens[0] = new BytesRefBuilder();
        }
        Arc<Long> arc = new Arc<>();
        BytesReader bytesReader = fst.getBytesReader();
        // Try highest order models first, and if they return
        // results, return that; else, fallback:
        double backoff = 1.0;
        List<LookupResult> results = new ArrayList<>(num);
        // We only add a given suffix once, from the highest
        // order model that saw it; for subsequent lower order
        // models we skip it:
        final Set<BytesRef> seen = new HashSet<>();
        for (int gram = grams - 1; gram >= 0; gram--) {
            BytesRefBuilder token = lastTokens[gram];
            // Don't make unigram predictions from empty string:
            if (token == null || (token.length() == 0 && key.length() > 0)) {
                //System.out.println("  gram=" + gram + ": skip: not enough input");
                continue;
            }
            if (endPosInc > 0 && gram <= endPosInc) {
                //System.out.println("  break: only holes now");
                break;
            }
            //System.out.println("try " + (gram+1) + " gram token=" + token.utf8ToString());
            // TODO: we could add fuzziness here
            // match the prefix portion exactly
            //Pair<Long,BytesRef> prefixOutput = null;
            Long prefixOutput = null;
            try {
                prefixOutput = lookupPrefix(fst, bytesReader, token.get(), arc);
            } catch (IOException bogus) {
                throw new RuntimeException(bogus);
            }
            if (prefixOutput == null) {
                // This model never saw this prefix, e.g. the
                // trigram model never saw context "purple mushroom"
                backoff *= ALPHA;
                continue;
            }
            // TODO: we could do this division at build time, and
            // bake it into the FST?
            // Denominator for computing scores from current
            // model's predictions:
            long contextCount = totTokens;
            BytesRef lastTokenFragment = null;
            for (int i = token.length() - 1; i >= 0; i--) {
                if (token.byteAt(i) == separator) {
                    BytesRef context = new BytesRef(token.bytes(), 0, i);
                    Long output = Util.get(fst, Util.toIntsRef(context, new IntsRefBuilder()));
                    assert output != null;
                    contextCount = decodeWeight(output);
                    lastTokenFragment = new BytesRef(token.bytes(), i + 1, token.length() - i - 1);
                    break;
                }
            }
            final BytesRefBuilder finalLastToken = new BytesRefBuilder();
            if (lastTokenFragment == null) {
                finalLastToken.copyBytes(token.get());
            } else {
                finalLastToken.copyBytes(lastTokenFragment);
            }
            CharsRefBuilder spare = new CharsRefBuilder();
            // complete top-N
            TopResults<Long> completions = null;
            try {
                // Because we store multiple models in one FST
                // (1gram, 2gram, 3gram), we must restrict the
                // search so that it only considers the current
                // model.  For highest order model, this is not
                // necessary since all completions in the FST
                // must be from this model, but for lower order
                // models we have to filter out the higher order
                // ones:
                // Must do num+seen.size() for queue depth because we may
                // reject up to seen.size() paths in acceptResult():
                Util.TopNSearcher<Long> searcher = new Util.TopNSearcher<Long>(fst, num, num + seen.size(), weightComparator) {

                    BytesRefBuilder scratchBytes = new BytesRefBuilder();

                    @Override
                    protected void addIfCompetitive(Util.FSTPath<Long> path) {
                        if (path.arc.label != separator) {
                            //System.out.println("    keep path: " + Util.toBytesRef(path.input, new BytesRef()).utf8ToString() + "; " + path + "; arc=" + path.arc);
                            super.addIfCompetitive(path);
                        } else {
                        //System.out.println("    prevent path: " + Util.toBytesRef(path.input, new BytesRef()).utf8ToString() + "; " + path + "; arc=" + path.arc);
                        }
                    }

                    @Override
                    protected boolean acceptResult(IntsRef input, Long output) {
                        Util.toBytesRef(input, scratchBytes);
                        finalLastToken.grow(finalLastToken.length() + scratchBytes.length());
                        int lenSav = finalLastToken.length();
                        finalLastToken.append(scratchBytes);
                        //System.out.println("    accept? input='" + scratchBytes.utf8ToString() + "'; lastToken='" + finalLastToken.utf8ToString() + "'; return " + (seen.contains(finalLastToken) == false));
                        boolean ret = seen.contains(finalLastToken.get()) == false;
                        finalLastToken.setLength(lenSav);
                        return ret;
                    }
                };
                // since this search is initialized with a single start node 
                // it is okay to start with an empty input path here
                searcher.addStartPaths(arc, prefixOutput, true, new IntsRefBuilder());
                completions = searcher.search();
                assert completions.isComplete;
            } catch (IOException bogus) {
                throw new RuntimeException(bogus);
            }
            int prefixLength = token.length();
            BytesRefBuilder suffix = new BytesRefBuilder();
            nextCompletion: for (Result<Long> completion : completions) {
                token.setLength(prefixLength);
                // append suffix
                Util.toBytesRef(completion.input, suffix);
                token.append(suffix);
                //System.out.println("    completion " + token.utf8ToString());
                // Skip this path if a higher-order model already
                // saw/predicted its last token:
                BytesRef lastToken = token.get();
                for (int i = token.length() - 1; i >= 0; i--) {
                    if (token.byteAt(i) == separator) {
                        assert token.length() - i - 1 > 0;
                        lastToken = new BytesRef(token.bytes(), i + 1, token.length() - i - 1);
                        break;
                    }
                }
                if (seen.contains(lastToken)) {
                    //System.out.println("      skip dup " + lastToken.utf8ToString());
                    continue nextCompletion;
                }
                seen.add(BytesRef.deepCopyOf(lastToken));
                spare.copyUTF8Bytes(token.get());
                LookupResult result = new LookupResult(spare.toString(), (long) (Long.MAX_VALUE * backoff * ((double) decodeWeight(completion.output)) / contextCount));
                results.add(result);
                assert results.size() == seen.size();
            //System.out.println("  add result=" + result);
            }
            backoff *= ALPHA;
        }
        Collections.sort(results, new Comparator<LookupResult>() {

            @Override
            public int compare(LookupResult a, LookupResult b) {
                if (a.value > b.value) {
                    return -1;
                } else if (a.value < b.value) {
                    return 1;
                } else {
                    // Tie break by UTF16 sort order:
                    return ((String) a.key).compareTo((String) b.key);
                }
            }
        });
        if (results.size() > num) {
            results.subList(num, results.size()).clear();
        }
        return results;
    }
}

Example 2 with Result

use of org.apache.lucene.util.fst.Util.Result in project lucene-solr by apache.

the class TestFSTs method testShortestPathsRandom.

public void testShortestPathsRandom() throws Exception {
    final Random random = random();
    int numWords = atLeast(1000);
    final TreeMap<String, Long> slowCompletor = new TreeMap<>();
    final TreeSet<String> allPrefixes = new TreeSet<>();
    final PositiveIntOutputs outputs = PositiveIntOutputs.getSingleton();
    final Builder<Long> builder = new Builder<>(FST.INPUT_TYPE.BYTE1, outputs);
    final IntsRefBuilder scratch = new IntsRefBuilder();
    for (int i = 0; i < numWords; i++) {
        String s;
        while (true) {
            s = TestUtil.randomSimpleString(random);
            if (!slowCompletor.containsKey(s)) {
                break;
            }
        }
        for (int j = 1; j < s.length(); j++) {
            allPrefixes.add(s.substring(0, j));
        }
        // weights 1..100
        int weight = TestUtil.nextInt(random, 1, 100);
        slowCompletor.put(s, (long) weight);
    }
    for (Map.Entry<String, Long> e : slowCompletor.entrySet()) {
        //System.out.println("add: " + e);
        builder.add(Util.toIntsRef(new BytesRef(e.getKey()), scratch), e.getValue());
    }
    final FST<Long> fst = builder.finish();
    //System.out.println("SAVE out.dot");
    //Writer w = new OutputStreamWriter(new FileOutputStream("out.dot"));
    //Util.toDot(fst, w, false, false);
    //w.close();
    BytesReader reader = fst.getBytesReader();
    //System.out.println("testing: " + allPrefixes.size() + " prefixes");
    for (String prefix : allPrefixes) {
        // 1. run prefix against fst, then complete by value
        //System.out.println("TEST: " + prefix);
        long prefixOutput = 0;
        FST.Arc<Long> arc = fst.getFirstArc(new FST.Arc<Long>());
        for (int idx = 0; idx < prefix.length(); idx++) {
            if (fst.findTargetArc((int) prefix.charAt(idx), arc, arc, reader) == null) {
                fail();
            }
            prefixOutput += arc.output;
        }
        final int topN = TestUtil.nextInt(random, 1, 10);
        Util.TopResults<Long> r = Util.shortestPaths(fst, arc, fst.outputs.getNoOutput(), minLongComparator, topN, true);
        assertTrue(r.isComplete);
        // 2. go thru whole treemap (slowCompletor) and check it's actually the best suggestion
        final List<Result<Long>> matches = new ArrayList<>();
        // TODO: could be faster... but it's slowCompletor for a reason
        for (Map.Entry<String, Long> e : slowCompletor.entrySet()) {
            if (e.getKey().startsWith(prefix)) {
                //System.out.println("  consider " + e.getKey());
                matches.add(new Result<>(Util.toIntsRef(new BytesRef(e.getKey().substring(prefix.length())), new IntsRefBuilder()), e.getValue() - prefixOutput));
            }
        }
        assertTrue(matches.size() > 0);
        Collections.sort(matches, new TieBreakByInputComparator<>(minLongComparator));
        if (matches.size() > topN) {
            matches.subList(topN, matches.size()).clear();
        }
        assertEquals(matches.size(), r.topN.size());
        for (int hit = 0; hit < r.topN.size(); hit++) {
            //System.out.println("  check hit " + hit);
            assertEquals(matches.get(hit).input, r.topN.get(hit).input);
            assertEquals(matches.get(hit).output, r.topN.get(hit).output);
        }
    }
}

Example 3 with Result

use of org.apache.lucene.util.fst.Util.Result in project lucene-solr by apache.

the class TestFSTs method testShortestPathsWFSTRandom.

/** like testShortestPathsRandom, but uses pairoutputs so we have both a weight and an output */
public void testShortestPathsWFSTRandom() throws Exception {
    int numWords = atLeast(1000);
    final TreeMap<String, TwoLongs> slowCompletor = new TreeMap<>();
    final TreeSet<String> allPrefixes = new TreeSet<>();
    PairOutputs<Long, Long> outputs = new PairOutputs<>(// weight
    PositiveIntOutputs.getSingleton(), // output
    PositiveIntOutputs.getSingleton());
    final Builder<Pair<Long, Long>> builder = new Builder<>(FST.INPUT_TYPE.BYTE1, outputs);
    final IntsRefBuilder scratch = new IntsRefBuilder();
    Random random = random();
    for (int i = 0; i < numWords; i++) {
        String s;
        while (true) {
            s = TestUtil.randomSimpleString(random);
            if (!slowCompletor.containsKey(s)) {
                break;
            }
        }
        for (int j = 1; j < s.length(); j++) {
            allPrefixes.add(s.substring(0, j));
        }
        // weights 1..100
        int weight = TestUtil.nextInt(random, 1, 100);
        // outputs 0..500
        int output = TestUtil.nextInt(random, 0, 500);
        slowCompletor.put(s, new TwoLongs(weight, output));
    }
    for (Map.Entry<String, TwoLongs> e : slowCompletor.entrySet()) {
        //System.out.println("add: " + e);
        long weight = e.getValue().a;
        long output = e.getValue().b;
        builder.add(Util.toIntsRef(new BytesRef(e.getKey()), scratch), outputs.newPair(weight, output));
    }
    final FST<Pair<Long, Long>> fst = builder.finish();
    //System.out.println("SAVE out.dot");
    //Writer w = new OutputStreamWriter(new FileOutputStream("out.dot"));
    //Util.toDot(fst, w, false, false);
    //w.close();
    BytesReader reader = fst.getBytesReader();
    //System.out.println("testing: " + allPrefixes.size() + " prefixes");
    for (String prefix : allPrefixes) {
        // 1. run prefix against fst, then complete by value
        //System.out.println("TEST: " + prefix);
        Pair<Long, Long> prefixOutput = outputs.getNoOutput();
        FST.Arc<Pair<Long, Long>> arc = fst.getFirstArc(new FST.Arc<Pair<Long, Long>>());
        for (int idx = 0; idx < prefix.length(); idx++) {
            if (fst.findTargetArc((int) prefix.charAt(idx), arc, arc, reader) == null) {
                fail();
            }
            prefixOutput = outputs.add(prefixOutput, arc.output);
        }
        final int topN = TestUtil.nextInt(random, 1, 10);
        Util.TopResults<Pair<Long, Long>> r = Util.shortestPaths(fst, arc, fst.outputs.getNoOutput(), minPairWeightComparator, topN, true);
        assertTrue(r.isComplete);
        // 2. go thru whole treemap (slowCompletor) and check it's actually the best suggestion
        final List<Result<Pair<Long, Long>>> matches = new ArrayList<>();
        // TODO: could be faster... but it's slowCompletor for a reason
        for (Map.Entry<String, TwoLongs> e : slowCompletor.entrySet()) {
            if (e.getKey().startsWith(prefix)) {
                //System.out.println("  consider " + e.getKey());
                matches.add(new Result<>(Util.toIntsRef(new BytesRef(e.getKey().substring(prefix.length())), new IntsRefBuilder()), outputs.newPair(e.getValue().a - prefixOutput.output1, e.getValue().b - prefixOutput.output2)));
            }
        }
        assertTrue(matches.size() > 0);
        Collections.sort(matches, new TieBreakByInputComparator<>(minPairWeightComparator));
        if (matches.size() > topN) {
            matches.subList(topN, matches.size()).clear();
        }
        assertEquals(matches.size(), r.topN.size());
        for (int hit = 0; hit < r.topN.size(); hit++) {
            //System.out.println("  check hit " + hit);
            assertEquals(matches.get(hit).input, r.topN.get(hit).input);
            assertEquals(matches.get(hit).output, r.topN.get(hit).output);
        }
    }
}