/*
Research Project:   Graphical Database for Category Theory
                    J. Bradbury, Dr. R. Rosebrugh, I. Rutherford
                    Mount Allison University 2001
File:               Partition.java
                    (author: Larry Barowski, Auburn University, 12/4/96)
Description:	      A partition class for CGD.
*/

public class Partition
{
private int sets_;
private Set allNodes_[];	// set of nodes in this partition
private Set equivTestSet_[];
private Set star_[];		// above set's nodes + descendents (ancestors)
private int type_;		// SIBLING or MATE

public final static int SIBLING = 0;
public final static int MATE = 1;



public Partition(int type, Set child_relation[], Set parent_relation[],
			Set descendent_relation[], Set ancestor_relation[],
			int numNodes_, Set node_subset)
	{
	type_ = type;

	// The number of sets in the partition will be at most the number
	// of nodes in the node subset.
	equivTestSet_ = new Set[node_subset.numberOfElements()];
	star_ = new Set[node_subset.numberOfElements()];
	allNodes_ = new Set[node_subset.numberOfElements()];

	sets_ = 0;

	// For each node, add to a set already found or start a new set.
	int i, j;
	for(i = node_subset.first(); i != -1; i = node_subset.next())
		{
		// Is node i equivalent to the first node of any of the sets?
		Set p;
		if(type_ == SIBLING)
			// p = parents of i
			p = (Set)(parent_relation[i].clone());
		else
			// p = children of i
			p = (Set)(child_relation[i].clone());
		p.intersect(node_subset);
		for(j = 0; j < sets_; j++)
			if(p.equals(equivTestSet_[j]))
				break;
		if(j >= sets_)
			// This is a new set.
			{
			sets_++;
			equivTestSet_[j] = p;
			allNodes_[j] = new Set();
			}

		allNodes_[j].includeElement(i);
		}
	for(j = 0; j < sets_; j++)
		{
		if(allNodes_[j] == null)
			allNodes_[j] = new Set();
		star_[j] = (Set)(allNodes_[j].clone());
		if(type_ == SIBLING)
			star_[j].indexedUnion(descendent_relation, allNodes_[j]);
		else
			star_[j].indexedUnion(ancestor_relation, allNodes_[j]);
		star_[j].intersect(node_subset);
		}
	}




public int size()
	{
	return sets_;
	}



public Set star(int i)
	{
	return star_[i];
	}



public Set members(int i)
	{
	return allNodes_[i];
	}



public String toString()
	{
	String result = new String();

	result += "Size: " + sets_ + "\n";
	int i;
	for(i = 0; i < sets_; i++)
		result += i + "\t" + allNodes_[i].toShortString() + "\n\t" +
				star_[i].toShortString() + "\n";

	return result;
	}
}