protected void expandFrontier(final HashSetChartCell cell) {
// connect edge as possible right non-term
for (int start = 0; start < cell.start(); start++) {
setSpanMaxEdgeFOM(chart.getCell(start, cell.start()), cell);
}
// connect edge as possible left non-term
for (int end = cell.end() + 1; end <= chart.size(); end++) {
setSpanMaxEdgeFOM(cell, chart.getCell(cell.end(), end));
}
}
protected void visitCell(final HashSetChartCell cell) {
final int start = cell.start(), end = cell.end();
Collection<Production> possibleProds;
ChartEdge edge;
final ChartEdge[] bestEdges = new ChartEdge[grammar.numNonTerms()]; // inits to null
// final int maxEdgesToAdd = (int) opts.param2;
final int maxEdgesToAdd = Integer.MAX_VALUE;
for (int mid = start + 1; mid <= end - 1; mid++) { // mid point
final HashSetChartCell leftCell = chart.getCell(start, mid);
final HashSetChartCell rightCell = chart.getCell(mid, end);
for (final int leftNT : leftCell.getLeftChildNTs()) {
for (final int rightNT : rightCell.getRightChildNTs()) {
possibleProds = grammar.getBinaryProductionsWithChildren(leftNT, rightNT);
if (possibleProds != null) {
for (final Production p : possibleProds) {
edge = chart.new ChartEdge(p, leftCell, rightCell);
addEdgeToArray(edge, bestEdges);
}
}
}
}
}
addBestEdgesToChart(cell, bestEdges, maxEdgesToAdd);
}
protected void addBestEdgesToChart(
final HashSetChartCell cell, final ChartEdge[] bestEdges, final int maxEdgesToAdd) {
ChartEdge edge, unaryEdge;
int numAdded = 0;
final PriorityQueue<ChartEdge> agenda = new PriorityQueue<ChartEdge>();
for (int i = 0; i < bestEdges.length; i++) {
if (bestEdges[i] != null) {
addEdgeToAgenda(bestEdges[i], agenda);
}
}
while (agenda.isEmpty() == false && numAdded <= maxEdgesToAdd) {
edge = agenda.poll();
// addedEdge = cell.addEdge(edge);
// if (addedEdge) {
final int nt = edge.prod.parent;
final float insideProb = edge.inside();
if (insideProb > cell.getInside(edge.prod.parent)) {
cell.updateInside(nt, insideProb);
// System.out.println(" addingEdge: " + edge);
numAdded++;
// Add unary productions to agenda so they can compete with binary productions
for (final Production p : grammar.getUnaryProductionsWithChild(edge.prod.parent)) {
unaryEdge = chart.new ChartEdge(p, cell);
addEdgeToAgenda(unaryEdge, agenda);
}
}
}
// TODO: should I decrease the maxEdgeFOM here according to the best edge NOT in the chart?
// won't this just be overrun when we expand the frontier?
if (agenda.isEmpty()) {
maxEdgeFOM[cell.start()][cell.end()] = Float.NEGATIVE_INFINITY;
} else {
maxEdgeFOM[cell.start()][cell.end()] = agenda.peek().fom;
}
}
protected void setSpanMaxEdgeFOM(
final HashSetChartCell leftCell, final HashSetChartCell rightCell) {
ChartEdge edge;
final int start = leftCell.start(), end = rightCell.end();
float bestFOM = maxEdgeFOM[start][end];
// System.out.println(" setSpanMax: " + leftCell + " && " + rightCell);
Collection<Production> possibleProds;
for (final int leftNT : leftCell.getLeftChildNTs()) {
for (final int rightNT : rightCell.getRightChildNTs()) {
possibleProds = grammar.getBinaryProductionsWithChildren(leftNT, rightNT);
if (possibleProds != null) {
for (final Production p : possibleProds) {
// final float prob = p.prob + leftCell.getInside(leftNT) +
// rightCell.getInside(rightNT);
edge = chart.new ChartEdge(p, leftCell, rightCell);
// System.out.println(" considering: " + edge);
if (edge.fom > bestFOM) {
bestFOM = edge.fom;
}
}
}
}
}
if (bestFOM > maxEdgeFOM[start][end]) {
final HashSetChartCell parentCell = chart.getCell(start, end);
// if (maxEdgeFOM[start][end] > Float.NEGATIVE_INFINITY) {
// spanAgenda.remove(parentCell);
// }
maxEdgeFOM[start][end] = bestFOM;
parentCell.fom = bestFOM;
// spanAgenda.add(parentCell);
// System.out.println(" addingSpan: " + parentCell);
}
}