FordFulkerson::FordFulkerson(FSgraph * g)
{
graph = g;
src = g->source;
tgt = g->target;
parent = (unsigned *) malloc(g->numVerts*sizeof(unsigned));
visited = (bool *) calloc(graph->numVerts,sizeof(bool));
//Find path
unsigned u,p;
flow = 0;
expanded_verts=0;
paths_searched=0;
while(findPath())
{
paths_searched++;
unsigned pathFlow = getResidual(parent[tgt-1],tgt);
for(p=tgt;p!=src;p=parent[p-1])
{
u = parent[p-1];
if(getResidual(u,p)<pathFlow)
pathFlow=getResidual(u,p);
}
for(p=tgt;p!=src;p=parent[p-1])
{
u = parent[p-1];
subResidual(u,p,pathFlow);
addResidual(p,u,pathFlow);
}
flow+=pathFlow;
}
}
int main ( long argc, char *argv[] )
{
long N = atoi(argv[1]);
double h = 1;
h = h/(N+1);
double h2 = h*h;
double d1 = 2/h2;
double d2 = -1/h2;
double* pre_u;
double* u;
double* residuals;
long i;
double residual;
pre_u = (double*) calloc (N+2,sizeof(double));
u = (double*) calloc (N+2,sizeof(double));
residuals = (double*) calloc (N,sizeof(double));
residual = getResidual(pre_u,residuals,N,d1,d2);
double threshold = residual;
threshold /= 1000000;
//Jacobi
long k;
int j;
for(k=0;;k++){
for(j=0;j<2;j++){
#pragma omp parallel for
for(i=1+j;i<=N;i += 2){
u[i] = (1 - d2*(u[i-1] + pre_u[i+1]))/d1;
}
}
#pragma omp parallel for
for(i=1;i<=N;i++){
pre_u[i] = u[i];
}
if((N<1000 && k%100!=0) || (N>=1000&&k%100000!=0)){
continue;
}
residual = getResidual(u,residuals,N,d1,d2);
if(residual<=threshold){
printf("%ld iterations\n",k+1);
break;
}
}
free(u);
free(pre_u);
free(residuals);
}
/* Maxflow / mincut algorithm :
* while has augmenting path
* find augmenting path
* calculate new capacities
*/
void MaxFlow(graphtp & g, int src, int dest)
{
out("Maxflow: entering\n");
float flowvalue = 0;
vpe P(g.size()); //parent node for node e.to is e.from
while(hasAugmentingPath(g, src, dest, P))
{
float capacity = INFINITY;
//find capacity
for(int v = dest; v != src; v = P[v]->from) {
out("v=%d\n", v);
assert(P[v] != NULL && "address of edge is null");
float resid_capac = getResidual(*P[v], P[v]->from, v);
capacity = std::min(capacity, resid_capac);
assert(capacity > 0 && "Capacity is negative ");
out("reading P[%d] (0x %ld), from=%d,to=%d,flow/cap=%f/%f residcap %f, capacity=%f\n",v, P[v], P[v]->from, P[v]->to, P[v]->flow, P[v]->capacity, resid_capac, capacity);
}
//augment flow by capacity
for(int v = dest; v != src; v = P[v]->from) {
float cap = capacity;
if(P[v]->backedge)
cap = -cap;
out("augment P[%d]->flow = %f by %f\n",v, P[v]->flow, cap);
P[v]->flow += cap;
}
flowvalue += capacity;
out("flowvalue = %f\n\n", flowvalue);
}
printf("Maxflow = %f\n", flowvalue);
}
double CTDLearner::getTemporalDifference(CStateCollection *oldState, CAction *action, double reward, CStateCollection *newState)
{
double newQ = 0.0, oldQ = 0.0;
double temporalDiff = 0.0;
int duration = 1;
if (action->isType(MULTISTEPACTION))
{
duration = dynamic_cast<CMultiStepAction *>(action)->getDuration();
}
// assert(lastEstimatedAction->getIndex() >= 0);
oldQ = qfunction->getValue(oldState, action); // Save old prediction: Q(st,at)
if (!newState->isResetState())
{
if (lastEstimatedAction == NULL)
{
lastEstimatedAction = qfunction->getMax(newState, qfunction->getActions(), actionDataSet);
}
newQ = qfunction->getValue(newState, lastEstimatedAction, actionDataSet->getActionData(lastEstimatedAction));
}
else
{
DebugPrint('t', "TD Learner: Last State of Episode, Action %d\n", qfunction->getActions()->getIndex(action));
}
temporalDiff = getResidual(oldQ, reward, duration, newQ);
DebugPrint('t', "OldQValue: %f\n", oldQ);
DebugPrint('t', "NewQValue: %f\n", newQ);
DebugPrint('t', "Reward: %f\n", reward);
DebugPrint('t', "TemporalDiff: %f\n", temporalDiff);
sendErrorToListeners(temporalDiff, oldState, action, NULL);
return temporalDiff;
}
//this is a shortest path algorithm to find an aumenting path
//if an edge can carry more flow, or if a backedge can diminish more flow
//that is the residual capacity, and that node gets marked and put in the que.
//
//to find the nodes in the mincut side, we look at the marked nodes,
//ie the nodes that are reachable from source are in one side, and mincut
//is the connections to the other side of the graph.
bool hasAugmentingPath(graphtp & g, int src, int dest, vpe & P)
{
out("hasAugmentingPath: entering\n");
P.clear();
P.reserve(g.size());
vi marked(g.size());
std::queue<int> q;
q.push(src);
marked[src] = true;
while(!q.empty())
{
int node = q.front();
q.pop();
out("q.top=%d\n", node);
for(ve::iterator it = g[node].begin(); it != g[node].end(); ++it)
{
out("edge %d-%d(%.2f/%.2f) \n", it->from, it->to, it->flow, it->capacity);
assert(node == it->from && "Edge does not have same from as node");
int w = it->to;
float resid_capac_to_w = getResidual(*it, it->from, it->to);
out("resid cap %d -> %d = %f (%f - %f)\n", node, w, resid_capac_to_w, it->capacity, it->flow);
if(resid_capac_to_w > 0 && !marked[w]) {
P[w] = const_cast<edge *> (&(*it));
out("setting P[%d] to = %ld\n",w, P[w]);
assert(P[w] != NULL && "address of edge is null");
marked[w] = true;
q.push(w);
}
}
}
out("hasAugmentingPath: returning %d\n\n", marked[dest]);
return marked[dest];
}
