+#include <cmath>
#include <xbt/log.h>
XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(loba);
void loba_bulk::load_balance()
{
- // write code here...
- xbt_die("Load-balancing algorithm \"bulk\" not implemented!");
+ float myLoad = get_load();
+
+ unsigned NbNwMinLoad = 0;
+ unsigned NbNwLowerLoad = 0;
+ unsigned NbNeighbours = pneigh.size();
+
+ double *S = new double[NbNeighbours];
+ for (unsigned i = 0; i < NbNeighbours; i++)
+ S[i] = 0.0;
+
+ // What is the minimum and maximum load under myLoad?
+ float minLoad = myLoad;
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ if (pneigh[i]->get_load() < minLoad) {
+ minLoad = pneigh[i]->get_load();
+ }
+ if (pneigh[i]->get_load() < myLoad) {
+ NbNwLowerLoad++;
+ }
+ }
+ for (unsigned i = 0; i < NbNeighbours; i++)
+ if (pneigh[i]->get_load() == minLoad)
+ NbNwMinLoad++;
+
+ float maxLoad = minLoad;
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ if (pneigh[i]->get_load() > minLoad && pneigh[i]->get_load() < myLoad)
+ if (maxLoad < pneigh[i]->get_load())
+ maxLoad = pneigh[i]->get_load();
+ }
+
+ double alpha = 0.0;
+
+ if (NbNwLowerLoad && NbNwMinLoad < NbNwLowerLoad) {
+ // There is one or many neighbors with minimum load but not
+ // all neighbors have minimum load
+ alpha = (1. / ((double) NbNwMinLoad + 2));
+ }
+ if (NbNwMinLoad == NbNwLowerLoad) {
+ // All neighbors have minimum load
+ alpha = (1. / ((double) NbNwMinLoad + 1));
+ }
+ float myS = 0.;
+ // There exist underloaded neighbors
+ if (NbNwMinLoad && myLoad != 0.0) {
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ if (pneigh[i]->get_load() == minLoad) {
+ S[i] = std::floor(alpha * (myLoad - minLoad));
+ myS += S[i];
+ } else {
+ if (pneigh[i]->get_load() < myLoad) {
+ S[i] = std::floor(alpha * (myLoad - pneigh[i]->get_load()));
+ myS += S[i];
+ }
+ }
+ }
+ // Check assumption 4.2 (b) page 520
+ bool HaveToCorrectS = false;
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ if (pneigh[i]->get_load() < myLoad) {
+ // Condition 4.6
+ if ((myLoad - myS) < (pneigh[i]->get_load() + S[i])) {
+ HaveToCorrectS = true;
+ }
+ }
+ }
+ if (HaveToCorrectS) {
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ while (((myLoad - myS) < pneigh[i]->get_load() + S[i])
+ && (S[i] > 0)) {
+ myS -= 1.0;
+ S[i] -= 1.0;
+ }
+ }
+ }
+ } // End there are underloaded neighbors;
+ for (unsigned i = 0; i < NbNeighbours; i++) {
+ send(pneigh[i], S[i]);
+ XBT_DEBUG("sent to %s", pneigh[i]->get_name());
+ }
+
+ delete[] S;
}
// Local variables:
