/**
* incremental version of satisfy that allows refinement after blocks are
* moved.
*
* - move blocks to new positions
* - repeatedly merge across most violated constraint until no more
* violated constraints exist
*
* Note: there is a special case to handle when the most violated constraint
* is between two variables in the same block. Then, we must split the block
* over an active constraint between the two variables. We choose the
* constraint with the most negative lagrangian multiplier.
*/
void IncSolver::satisfy() {
#ifdef RECTANGLE_OVERLAP_LOGGING
ofstream f(LOGFILE,ios::app);
f<<"satisfy_inc()..."<<endl;
#endif
splitBlocks();
long splitCtr = 0;
Constraint* v = NULL;
while((v=mostViolated(inactive))&&(v->equality || v->slack() < ZERO_UPPERBOUND)) {
assert(!v->active);
Block *lb = v->left->block, *rb = v->right->block;
if(lb != rb) {
lb->merge(rb,v);
}
else {
if(lb->isActiveDirectedPathBetween(v->right,v->left)) {
// cycle found, relax the violated, cyclic constraint
v->gap = v->slack();
continue;
}
if(splitCtr++>10000) {
throw "Cycle Error!";
}
// constraint is within block, need to split first
inactive.push_back(lb->splitBetween(v->left,v->right,lb,rb));
lb->merge(rb,v);
bs->insert(lb);
}
}
#ifdef RECTANGLE_OVERLAP_LOGGING
f<<" finished merges."<<endl;
#endif
bs->cleanup();
for(unsigned i=0; i<m; i++) {
v=cs[i];
if(v->slack() < ZERO_UPPERBOUND) {
ostringstream s;
s<<"Unsatisfied constraint: "<<*v;
#ifdef RECTANGLE_OVERLAP_LOGGING
ofstream f(LOGFILE,ios::app);
f<<s.str()<<endl;
#endif
throw s.str().c_str();
}
}
#ifdef RECTANGLE_OVERLAP_LOGGING
f<<" finished cleanup."<<endl;
printBlocks();
#endif
}
void IncSolver::solve() {
#ifdef RECTANGLE_OVERLAP_LOGGING
ofstream f(LOGFILE,ios::app);
f<<"solve_inc()..."<<endl;
#endif
double lastcost,cost = bs->cost();
do {
lastcost=cost;
satisfy();
splitBlocks();
cost = bs->cost();
#ifdef RECTANGLE_OVERLAP_LOGGING
f<<" cost="<<cost<<endl;
#endif
} while(fabs(lastcost-cost)>0.0001);
}
