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LUCENE-2716: Improve automaton's MinimizeOperations.minimizeHopcroft() to not create so many objects 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1026168 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Uwe Schindler 2010-10-21 22:31:58 +00:00
parent 29678a0c25
commit d8208f5646
1 changed files with 66 additions and 79 deletions
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145
lucene/src/java/org/apache/lucene/util/automaton/MinimizationOperations.java
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@ -56,11 +56,6 @@ final public class MinimizationOperations {
//if (a.hash_code == 0) a.hash_code = 1;
}
private static <T> void initialize(ArrayList<T> list, int size) {
for (int i = 0; i < size; i++)
list.add(null);
}
/**
* Minimizes the given automaton using Hopcroft's algorithm.
*/
@ -73,66 +68,55 @@ final public class MinimizationOperations {
}
a.totalize();
int[] sigma = a.getStartPoints();
// initialize data structures
ArrayList<ArrayList<LinkedList<State>>> reverse = new ArrayList<ArrayList<LinkedList<State>>>();
final int[] sigma = a.getStartPoints();
final State[] states = a.getNumberedStates();
for (int q = 0; q < states.length; q++) {
ArrayList<LinkedList<State>> v = new ArrayList<LinkedList<State>>();
initialize(v, sigma.length);
reverse.add(v);
}
boolean[][] reverse_nonempty = new boolean[states.length][sigma.length];
ArrayList<LinkedList<State>> partition = new ArrayList<LinkedList<State>>();
initialize(partition, states.length);
int[] block = new int[states.length];
StateList[][] active = new StateList[states.length][sigma.length];
StateListNode[][] active2 = new StateListNode[states.length][sigma.length];
LinkedList<IntPair> pending = new LinkedList<IntPair>();
boolean[][] pending2 = new boolean[sigma.length][states.length];
ArrayList<State> split = new ArrayList<State>();
boolean[] split2 = new boolean[states.length];
ArrayList<Integer> refine = new ArrayList<Integer>();
boolean[] refine2 = new boolean[states.length];
ArrayList<ArrayList<State>> splitblock = new ArrayList<ArrayList<State>>();
initialize(splitblock, states.length);
for (int q = 0; q < states.length; q++) {
splitblock.set(q, new ArrayList<State>());
partition.set(q, new LinkedList<State>());
for (int x = 0; x < sigma.length; x++) {
reverse.get(q).set(x, new LinkedList<State>());
final int sigmaLen = sigma.length, statesLen = states.length;
@SuppressWarnings("unchecked") final LinkedList<State>[][] reverse =
(LinkedList<State>[][]) new LinkedList[statesLen][sigmaLen];
@SuppressWarnings("unchecked") final LinkedList<State>[] partition =
(LinkedList<State>[]) new LinkedList[statesLen];
@SuppressWarnings("unchecked") final ArrayList<State>[] splitblock =
(ArrayList<State>[]) new ArrayList[statesLen];
final int[] block = new int[statesLen];
final StateList[][] active = new StateList[statesLen][sigmaLen];
final StateListNode[][] active2 = new StateListNode[statesLen][sigmaLen];
final LinkedList<IntPair> pending = new LinkedList<IntPair>();
final boolean[][] pending2 = new boolean[sigmaLen][statesLen];
final ArrayList<State> split = new ArrayList<State>();
final boolean[] split2 = new boolean[statesLen];
final ArrayList<Integer> refine = new ArrayList<Integer>();
final boolean[] refine2 = new boolean[statesLen];
for (int q = 0; q < statesLen; q++) {
splitblock[q] = new ArrayList<State>();
partition[q] = new LinkedList<State>();
for (int x = 0; x < sigmaLen; x++) {
active[q][x] = new StateList();
}
}
// find initial partition and reverse edges
for (int q = 0; q < states.length; q++) {
State qq = states[q];
int j;
if (qq.accept) j = 0;
else j = 1;
partition.get(j).add(qq);
for (int q = 0; q < statesLen; q++) {
final State qq = states[q];
final int j = qq.accept ? 0 : 1;
partition[j].add(qq);
block[qq.number] = j;
for (int x = 0; x < sigma.length; x++) {
int y = sigma[x];
State p = qq.step(y);
reverse.get(p.number).get(x).add(qq);
reverse_nonempty[p.number][x] = true;
for (int x = 0; x < sigmaLen; x++) {
final LinkedList<State>[] r =
reverse[qq.step(sigma[x]).number];
if (r[x] == null)
r[x] = new LinkedList<State>();
r[x].add(qq);
}
}
// initialize active sets
for (int j = 0; j <= 1; j++)
for (int x = 0; x < sigma.length; x++)
for (State qq : partition.get(j))
if (reverse_nonempty[qq.number][x]) active2[qq.number][x] = active[j][x]
.add(qq);
for (int x = 0; x < sigmaLen; x++)
for (State qq : partition[j])
if (reverse[qq.number][x] != null)
active2[qq.number][x] = active[j][x].add(qq);
// initialize pending
for (int x = 0; x < sigma.length; x++) {
int a0 = active[0][x].size;
int a1 = active[1][x].size;
int j;
if (a0 <= a1) j = 0;
else j = 1;
for (int x = 0; x < sigmaLen; x++) {
final int j = (active[0][x].size <= active[1][x].size) ? 0 : 1;
pending.add(new IntPair(j, x));
pending2[x][j] = true;
}
@ -140,33 +124,36 @@ final public class MinimizationOperations {
int k = 2;
while (!pending.isEmpty()) {
IntPair ip = pending.removeFirst();
int p = ip.n1;
int x = ip.n2;
final int p = ip.n1;
final int x = ip.n2;
pending2[x][p] = false;
// find states that need to be split off their blocks
for (StateListNode m = active[p][x].first; m != null; m = m.next)
for (State s : reverse.get(m.q.number).get(x))
for (StateListNode m = active[p][x].first; m != null; m = m.next) {
final LinkedList<State> r = reverse[m.q.number][x];
if (r != null) for (State s : r) {
if (!split2[s.number]) {
split2[s.number] = true;
split.add(s);
int j = block[s.number];
splitblock.get(j).add(s);
final int j = block[s.number];
splitblock[j].add(s);
if (!refine2[j]) {
refine2[j] = true;
refine.add(j);
}
}
}
}
// refine blocks
for (int j : refine) {
if (splitblock.get(j).size() < partition.get(j).size()) {
LinkedList<State> b1 = partition.get(j);
LinkedList<State> b2 = partition.get(k);
for (State s : splitblock.get(j)) {
if (splitblock[j].size() < partition[j].size()) {
final LinkedList<State> b1 = partition[j];
final LinkedList<State> b2 = partition[k];
for (State s : splitblock[j]) {
b1.remove(s);
b2.add(s);
block[s.number] = k;
for (int c = 0; c < sigma.length; c++) {
StateListNode sn = active2[s.number][c];
for (int c = 0; c < sigmaLen; c++) {
final StateListNode sn = active2[s.number][c];
if (sn != null && sn.sl == active[j][c]) {
sn.remove();
active2[s.number][c] = active[k][c].add(s);
@ -174,9 +161,9 @@ final public class MinimizationOperations {
}
}
// update pending
for (int c = 0; c < sigma.length; c++) {
int aj = active[j][c].size;
int ak = active[k][c].size;
for (int c = 0; c < sigmaLen; c++) {
final int aj = active[j][c].size;
final int ak = active[k][c].size;
if (!pending2[c][j] && 0 < aj && aj <= ak) {
pending2[c][j] = true;
pending.add(new IntPair(j, c));
@ -187,10 +174,10 @@ final public class MinimizationOperations {
}
k++;
}
for (State s : splitblock.get(j))
for (State s : splitblock[j])
split2[s.number] = false;
refine2[j] = false;
splitblock.get(j).clear();
splitblock[j].clear();
}
split.clear();
refine.clear();
@ -198,9 +185,9 @@ final public class MinimizationOperations {
// make a new state for each equivalence class, set initial state
State[] newstates = new State[k];
for (int n = 0; n < newstates.length; n++) {
State s = new State();
final State s = new State();
newstates[n] = s;
for (State q : partition.get(n)) {
for (State q : partition[n]) {
if (q == a.initial) a.initial = s;
s.accept = q.accept;
s.number = q.number; // select representative
@ -209,7 +196,7 @@ final public class MinimizationOperations {
}
// build transitions and set acceptance
for (int n = 0; n < newstates.length; n++) {
State s = newstates[n];
final State s = newstates[n];
s.accept = states[s.number].accept;
for (Transition t : states[s.number].getTransitions())
s.addTransition(new Transition(t.min, t.max, newstates[t.to.number]));
@ -218,9 +205,9 @@ final public class MinimizationOperations {
a.removeDeadTransitions();
}
static class IntPair {
static final class IntPair {
int n1, n2;
final int n1, n2;
IntPair(int n1, int n2) {
this.n1 = n1;
@ -228,7 +215,7 @@ final public class MinimizationOperations {
}
}
static class StateList {
static final class StateList {
int size;
@ -239,13 +226,13 @@ final public class MinimizationOperations {
}
}
static class StateListNode {
static final class StateListNode {
State q;
final State q;
StateListNode next, prev;
StateList sl;
final StateList sl;
StateListNode(State q, StateList sl) {
this.q = q;