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LUCENE-3846: add some nocommits; carry over test from original patch 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene3846@1401358 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Michael McCandless 2012-10-23 17:39:59 +00:00
parent 935e4b7aef
commit 1e422e3e5e
3 changed files with 298 additions and 3 deletions
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4
lucene/core/src/java/org/apache/lucene/util/automaton/Transition.java
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@ -139,6 +139,9 @@ public class Transition implements Cloneable {
static void appendCharString(int c, StringBuilder b) {
if (c >= 0x21 && c <= 0x7e && c != '\\' && c != '"') b.appendCodePoint(c);
else {
b.append("\\\\U" + Integer.toHexString(c));
// nocommit
/*
b.append("\\\\U");
String s = Integer.toHexString(c);
if (c < 0x10) b.append("0000000").append(s);
@ -149,6 +152,7 @@ public class Transition implements Cloneable {
else if (c < 0x1000000) b.append("00").append(s);
else if (c < 0x10000000) b.append("0").append(s);
else b.append(s);
*/
}
}

37
lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/FuzzySuggester.java
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@ -15,7 +15,10 @@ package org.apache.lucene.search.suggest.analyzing;
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
@ -61,9 +64,13 @@ public final class FuzzySuggester extends AnalyzingSuggester {
private final boolean transpositions;
private final int minPrefix;
// nocommit separate param for "min length before we
// enable fuzzy"? eg type "nusglasses" into google...
/**
* The default minimum shared (non-fuzzy) prefix. Set to <tt>2</tt>
*/
// nocommit should we do 1...?
public static final int DEFAULT_MIN_PREFIX = 2;
/**
@ -156,7 +163,14 @@ public final class FuzzySuggester extends AnalyzingSuggester {
Automaton prefix = BasicAutomata.makeString(path.ints, path.offset, minPrefix);
int ints[] = new int[path.length-minPrefix];
System.arraycopy(path.ints, path.offset+minPrefix, ints, 0, ints.length);
LevenshteinAutomata lev = new LevenshteinAutomata(ints, 256, transpositions);
// nocommit i think we should pass 254 max? ie
// exclude 0xff ... this way we can't 'edit away'
// the sep? or ... maybe we want to allow that to
// be edited away?
// nocommit also the 0 byte ... we use that as
// trailer ... we probably shouldn't allow that byte
// to be edited (we could add alphaMin?)
LevenshteinAutomata lev = new LevenshteinAutomata(ints, 255, transpositions);
Automaton levAutomaton = lev.toAutomaton(maxEdits);
Automaton combined = BasicOperations.concatenate(Arrays.asList(prefix, levAutomaton));
combined.setDeterministic(true); // its like the special case in concatenate itself, except we cloneExpanded already
@ -164,6 +178,11 @@ public final class FuzzySuggester extends AnalyzingSuggester {
upto++;
}
}
// nocommit maybe we should reduce the LevN? the added
// arcs add cost during intersect (extra FST arc
// lookups...). could be net win...
if (subs.length == 0) {
return BasicAutomata.makeEmpty(); // matches nothing
} else if (subs.length == 1) {
@ -186,8 +205,20 @@ public final class FuzzySuggester extends AnalyzingSuggester {
@Override
public List<Path<Pair<Long,BytesRef>>> intersectAll() throws IOException {
return FSTUtil.intersectPrefixPaths(toLevenshteinAutomata(automaton),fst);
// nocommit we don't "penalize" for edits
// ... shouldn't we? ie, ed=0 completions should have
// higher rank than ed=1, at the same "weight"? maybe
// we can punt on this for starters ... or maybe we
// can re-run each prefix path through lev0, lev1,
// lev2 to figure out the number of edits?
Automaton levA = toLevenshteinAutomata(automaton);
/*
Writer w = new OutputStreamWriter(new FileOutputStream("out.dot"), "UTF-8");
w.write(levA.toDot());
w.close();
System.out.println("Wrote LevA to out.dot");
*/
return FSTUtil.intersectPrefixPaths(levA, fst);
}
}
}

260
lucene/suggest/src/test/org/apache/lucene/search/suggest/analyzing/FuzzySuggesterTest.java
View File

@ -700,6 +700,9 @@ public class FuzzySuggesterTest extends LuceneTestCase {
System.out.println(" analyzed: " + analyzedKey);
}
TokenStreamToAutomaton tokenStreamToAutomaton = suggester.getTokenStreamToAutomaton();
// nocommit this is putting fox in charge of hen
// house! ie maybe we have a bug in suggester.toLevA ...
Automaton automaton = suggester.toLevenshteinAutomata(suggester.toLookupAutomaton(analyzedKey));
assertTrue(automaton.isDeterministic());
// TODO: could be faster... but its slowCompletor for a reason
@ -834,4 +837,261 @@ public class FuzzySuggesterTest extends LuceneTestCase {
return builder.toString();
}
private String randomSimpleString(int maxLen) {
final int len = _TestUtil.nextInt(random(), 1, maxLen);
final char[] chars = new char[len];
for(int j=0;j<len;j++) {
chars[j] = (char) ('a' + random().nextInt(4));
}
return new String(chars);
}
public void testRandom2() throws Throwable {
final int NUM = atLeast(200);
final List<TermFreq> answers = new ArrayList<TermFreq>();
final Set<String> seen = new HashSet<String>();
for(int i=0;i<NUM;i++) {
// nocommit mixin some unicode here?
final String s = randomSimpleString(8);
if (!seen.contains(s)) {
answers.add(new TermFreq(s, random().nextInt(1000)));
seen.add(s);
}
}
Collections.sort(answers, new Comparator<TermFreq>() {
@Override
public int compare(TermFreq a, TermFreq b) {
return a.term.compareTo(b.term);
}
});
if (VERBOSE) {
System.out.println("\nTEST: targets");
for(TermFreq tf : answers) {
System.out.println(" " + tf.term.utf8ToString() + " freq=" + tf.v);
}
}
Analyzer a = new MockAnalyzer(random(), MockTokenizer.KEYWORD, false);
int maxEdits = random().nextBoolean() ? 1 : 2;
int prefixLen = random().nextInt(4);
boolean transpositions = random().nextBoolean();
// TODO: test graph analyzers
// TODO: test exactFirst / preserveSep permutations
FuzzySuggester suggest = new FuzzySuggester(a, a, 0, 256, -1, maxEdits, transpositions, prefixLen);
if (VERBOSE) {
System.out.println("TEST: maxEdits=" + maxEdits + " prefixLen=" + prefixLen + " transpositions=" + transpositions + " num=" + NUM);
}
Collections.shuffle(answers, random());
suggest.build(new TermFreqArrayIterator(answers.toArray(new TermFreq[answers.size()])));
final int ITERS = atLeast(100);
for(int iter=0;iter<ITERS;iter++) {
final String frag = randomSimpleString(6);
if (VERBOSE) {
System.out.println("\nTEST: iter frag=" + frag);
}
final List<LookupResult> expected = slowFuzzyMatch(prefixLen, maxEdits, transpositions, answers, frag);
if (VERBOSE) {
System.out.println(" expected: " + expected.size());
for(LookupResult c : expected) {
System.out.println(" " + c);
}
}
final List<LookupResult> actual = suggest.lookup(frag, false, NUM);
if (VERBOSE) {
System.out.println(" actual: " + actual.size());
for(LookupResult c : actual) {
System.out.println(" " + c);
}
}
// nocommit must fix lookup to tie break properly!!:
Collections.sort(actual, new CompareByCostThenAlpha());
final int limit = Math.min(expected.size(), actual.size());
for(int ans=0;ans<limit;ans++) {
final LookupResult c0 = expected.get(ans);
final LookupResult c1 = actual.get(ans);
assertEquals("expected " + c0.key +
" but got " + c1.key,
0,
CHARSEQUENCE_COMPARATOR.compare(c0.key, c1.key));
assertEquals(c0.value, c1.value);
}
assertEquals(expected.size(), actual.size());
}
}
private List<LookupResult> slowFuzzyMatch(int prefixLen, int maxEdits, boolean allowTransposition, List<TermFreq> answers, String frag) {
final List<LookupResult> results = new ArrayList<LookupResult>();
final int fragLen = frag.length();
for(TermFreq tf : answers) {
//System.out.println(" check s=" + tf.term.utf8ToString());
boolean prefixMatches = true;
for(int i=0;i<prefixLen;i++) {
if (i == fragLen) {
// Prefix still matches:
break;
}
if (i == tf.term.length || tf.term.bytes[i] != (byte) frag.charAt(i)) {
prefixMatches = false;
break;
}
}
//System.out.println(" prefixMatches=" + prefixMatches);
if (prefixMatches) {
final int len = tf.term.length;
if (len >= fragLen-maxEdits) {
// OK it's possible:
//System.out.println(" possible");
int d;
final String s = tf.term.utf8ToString();
if (fragLen == prefixLen) {
d = 0;
} else if (false && len < fragLen) {
d = getDistance(frag, s, allowTransposition);
} else {
//System.out.println(" try loop");
d = maxEdits + 1;
for(int ed=-maxEdits;ed<=maxEdits;ed++) {
if (s.length() < fragLen - ed) {
continue;
}
String check = s.substring(0, fragLen-ed);
d = getDistance(frag, check, allowTransposition);
//System.out.println(" sub check s=" + check + " d=" + d);
if (d <= maxEdits) {
break;
}
}
}
if (d <= maxEdits) {
results.add(new LookupResult(tf.term.utf8ToString(), tf.v));
}
}
}
Collections.sort(results, new CompareByCostThenAlpha());
}
return results;
}
private static class CharSequenceComparator implements Comparator<CharSequence> {
@Override
public int compare(CharSequence o1, CharSequence o2) {
final int l1 = o1.length();
final int l2 = o2.length();
final int aStop = Math.min(l1, l2);
for (int i = 0; i < aStop; i++) {
int diff = o1.charAt(i) - o2.charAt(i);
if (diff != 0) {
return diff;
}
}
// One is a prefix of the other, or, they are equal:
return l1 - l2;
}
}
private static final Comparator<CharSequence> CHARSEQUENCE_COMPARATOR = new CharSequenceComparator();
public class CompareByCostThenAlpha implements 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 {
final int c = CHARSEQUENCE_COMPARATOR.compare(a.key, b.key);
assert c != 0: "term=" + a.key;
return c;
}
}
}
// NOTE: copied from
// modules/suggest/src/java/org/apache/lucene/search/spell/LuceneLevenshteinDistance.java
// and tweaked to return the edit distance not the float
// lucene measure
/* Finds unicode (code point) Levenstein (edit) distance
* between two strings, including transpositions. */
public int getDistance(String target, String other, boolean allowTransposition) {
IntsRef targetPoints;
IntsRef otherPoints;
int n;
int d[][]; // cost array
// NOTE: if we cared, we could 3*m space instead of m*n space, similar to
// what LevenshteinDistance does, except cycling thru a ring of three
// horizontal cost arrays... but this comparator is never actually used by
// DirectSpellChecker, its only used for merging results from multiple shards
// in "distributed spellcheck", and its inefficient in other ways too...
// cheaper to do this up front once
targetPoints = toIntsRef(target);
otherPoints = toIntsRef(other);
n = targetPoints.length;
final int m = otherPoints.length;
d = new int[n+1][m+1];
if (n == 0 || m == 0) {
if (n == m) {
return 0;
}
else {
return Math.max(n, m);
}
}
// indexes into strings s and t
int i; // iterates through s
int j; // iterates through t
int t_j; // jth character of t
int cost; // cost
for (i = 0; i<=n; i++) {
d[i][0] = i;
}
for (j = 0; j<=m; j++) {
d[0][j] = j;
}
for (j = 1; j<=m; j++) {
t_j = otherPoints.ints[j-1];
for (i=1; i<=n; i++) {
cost = targetPoints.ints[i-1]==t_j ? 0 : 1;
// minimum of cell to the left+1, to the top+1, diagonally left and up +cost
d[i][j] = Math.min(Math.min(d[i-1][j]+1, d[i][j-1]+1), d[i-1][j-1]+cost);
// transposition
if (allowTransposition && i > 1 && j > 1 && targetPoints.ints[i-1] == otherPoints.ints[j-2] && targetPoints.ints[i-2] == otherPoints.ints[j-1]) {
d[i][j] = Math.min(d[i][j], d[i-2][j-2] + cost);
}
}
}
return d[n][m];
}
private static IntsRef toIntsRef(String s) {
IntsRef ref = new IntsRef(s.length()); // worst case
int utf16Len = s.length();
for (int i = 0, cp = 0; i < utf16Len; i += Character.charCount(cp)) {
cp = ref.ints[ref.length++] = Character.codePointAt(s, i);
}
return ref;
}
}