/** Find an edge group coloring in a bipartite group graph.
* The algorithm used here is a variant of the menu graph method.
* It maintains a separate menu graph for each output, and a maximum
* matching for each. It also maintains a "deficit" for each edge group,
* which is the number of menu graphs for which the group is unmatched.
* It then repeatedly selects the group with the largest deficit and
* adjusts its menu to reduce its deficit.
* Once all deficits are zero, it colors the edges based on the matchings
* in the menu graphs.
* @param g is a reference to the graph
* @param edgeColors is an array indexed by edge numbers which is allocated
* by the caller; on return edgeColors[e] is the color assigned to edge e
* @return the number of colors used
*/
egGmenu::egGmenu(GroupGraph& g, int edgeColors[]) : egMenu(g, edgeColors) {
// create heap sorted by negative group size
Dheap<int> groups(gp->M());
for (int grp = 1; grp <= gp->M(); grp++) {
if (gp->groupSize(grp) > 0)
groups.insert(grp,-(gp->groupSize(grp)));
}
// repeatedly select next largest group and expand menu until it
// is matched in all its menu graphs
maxColor = max(g.maxGroupCountIn(), g.maxDegreeOut());
while (!groups.empty()) {
int grp = groups.deletemin();
vertex u = gp->input(gp->firstEdgeInGroup(grp));
int k = (maxColor + (gp->groupCount(u)-1))/gp->groupCount(u);
while (true) {
// select available color with the largest gain for grp
int best = 0; int bestGain = 0;
for (int c = avail[u].first(); c != 0 && c <= maxColor;
c = avail[u].next(c)) {
int cgain = gain(c,grp);
if (cgain > bestGain) {
best = c; bestGain = cgain;
}
}
if (bestGain <= 0 || menuSize(grp) >= k) {
maxColor++; best = maxColor; resetMenu(grp);
k = (maxColor + (gp->groupCount(u)-1))/
gp->groupCount(u);
}
if (growMenu(grp, best) == 0) break;
}
}
for (vertex v = gp->firstOut(); v != 0; v = gp->nextOut(v)) {
Graph& mg = *mgraf[v]; dynamicMatch& dm = *dymatch[v];
// now color the edges using the matching
for (edge e = gp->firstAt(v); e != 0; e = gp->nextAt(v,e)) {
color[e] = mg.right(dm.matchEdge(gx[e]))-gp->degree(v);
}
}
}
u32 cPopMenu::itemBelowPoint( const cPoint & pt )
{
cPoint menuPos(position().x + _barLeft, position().y + _itemTopLeftPoint.y - 2); cSize menuSize(barWidth(), _itemHeight * _items.size());
cRect rect(menuPos, menuPos + menuSize);
if( rect.surrounds( pt ) ) {
u32 item = (pt.y - menuPos.y ) / _itemHeight;
if( item > _items.size() - 1)
item = _items.size() - 1;
return item;
}
return (u32)-1;
}