/**
* Minimal ordered groebner basis.
*
* @param Fp a Groebner base.
* @return a reduced Groebner base of Fp.
*/
@SuppressWarnings("cast")
@Override
public List<GenPolynomial<C>> minimalGB(List<GenPolynomial<C>> Fp) {
GenPolynomial<C> a;
ArrayList<GenPolynomial<C>> G;
G = new ArrayList<GenPolynomial<C>>(Fp.size());
ListIterator<GenPolynomial<C>> it = Fp.listIterator();
while (it.hasNext()) {
a = it.next();
if (a.length() != 0) { // always true
// already monic a = a.monic();
G.add(a);
}
}
if (G.size() <= 1) {
return G;
}
ExpVector e;
ExpVector f;
GenPolynomial<C> p;
ArrayList<GenPolynomial<C>> F;
F = new ArrayList<GenPolynomial<C>>(G.size());
boolean mt;
while (G.size() > 0) {
a = G.remove(0);
e = a.leadingExpVector();
it = G.listIterator();
mt = false;
while (it.hasNext() && !mt) {
p = it.next();
f = p.leadingExpVector();
mt = e.multipleOf(f);
}
it = F.listIterator();
while (it.hasNext() && !mt) {
p = it.next();
f = p.leadingExpVector();
mt = e.multipleOf(f);
}
if (!mt) {
F.add(a);
} else {
// System.out.println("dropped " + a.length());
}
}
G = F;
if (G.size() <= 1) {
return G;
}
Collections.reverse(G); // important for lex GB
MiMPIReducerServer<C>[] mirs = (MiMPIReducerServer<C>[]) new MiMPIReducerServer[G.size()];
int i = 0;
F = new ArrayList<GenPolynomial<C>>(G.size());
while (G.size() > 0) {
a = G.remove(0);
// System.out.println("doing " + a.length());
List<GenPolynomial<C>> R = new ArrayList<GenPolynomial<C>>(G.size() + F.size());
R.addAll(G);
R.addAll(F);
mirs[i] = new MiMPIReducerServer<C>(R, a);
pool.addJob(mirs[i]);
i++;
F.add(a);
}
G = F;
F = new ArrayList<GenPolynomial<C>>(G.size());
for (i = 0; i < mirs.length; i++) {
a = mirs[i].getNF();
F.add(a);
}
return F;
}
/**
* Distributed Groebner base, part for MPI master.
*
* @param modv number of module variables.
* @param F polynomial list.
* @return GB(F) a Groebner base of F or null, if a IOException occurs.
*/
public List<GenPolynomial<C>> GBmaster(int modv, List<GenPolynomial<C>> F)
throws MPIException, IOException {
List<GenPolynomial<C>> G = new ArrayList<GenPolynomial<C>>();
GenPolynomial<C> p;
PairList<C> pairlist = null;
boolean oneInGB = false;
// int l = F.size();
int unused = 0;
ListIterator<GenPolynomial<C>> it = F.listIterator();
while (it.hasNext()) {
p = it.next();
if (p.length() > 0) {
p = p.monic();
if (p.isONE()) {
oneInGB = true;
G.clear();
G.add(p);
// return G; must signal termination to others
}
if (!oneInGB) {
G.add(p);
}
if (pairlist == null) {
pairlist = strategy.create(modv, p.ring);
if (!p.ring.coFac.isField()) {
throw new IllegalArgumentException("coefficients not from a field");
}
}
// theList not updated here
if (p.isONE()) {
unused = pairlist.putOne();
} else {
unused = pairlist.put(p);
}
} else {
// l--;
}
}
// if (l <= 1) {
// return G; must signal termination to others
// }
logger.info("done pairlist, initialize DHT: " + unused);
DistHashTableMPI<Integer, GenPolynomial<C>> theList =
new DistHashTableMPI<Integer, GenPolynomial<C>>(engine);
theList.init();
// logger.info("done DHT: " + theList);
List<GenPolynomial<C>> al = pairlist.getList();
for (int i = 0; i < al.size(); i++) {
// no wait required
GenPolynomial<C> nn = theList.put(Integer.valueOf(i), al.get(i));
if (nn != null) {
logger.info("double polynomials " + i + ", nn = " + nn + ", al(i) = " + al.get(i));
}
}
Terminator fin = new Terminator(threads - 1);
MPIReducerServer<C> R;
for (int i = 1; i < threads; i++) {
logger.debug("addJob " + i + " of " + threads);
MPIChannel chan = new MPIChannel(engine, i); // closed in server
R = new MPIReducerServer<C>(i, fin, chan, theList, pairlist);
pool.addJob(R);
}
logger.debug("main loop waiting");
fin.waitDone();
int ps = theList.size();
logger.info("#distributed list = " + ps);
// make sure all polynomials arrived: not needed in master
// G = (ArrayList)theList.values();
G = pairlist.getList();
if (ps != G.size()) {
logger.info("#distributed list = " + theList.size() + " #pairlist list = " + G.size());
}
long time = System.currentTimeMillis();
List<GenPolynomial<C>> Gp = minimalGB(G); // not jet distributed but threaded
time = System.currentTimeMillis() - time;
logger.debug("parallel gbmi = " + time);
G = Gp;
logger.info("theList.terminate()");
theList.terminate();
logger.info("end" + pairlist);
return G;
}