code: public void addAtoms(Atom[] iAtoms, BoundingBox icoordbounds, Atom[] jAtoms, BoundingBox jcoordbounds) {
  		this.iAtoms = Calc.atomsToPoints(iAtoms);
  		this.iAtomObjects = iAtoms;
  
  		if (icoordbounds!=null) {
  			this.ibounds = icoordbounds;
  		} else {
  			this.ibounds = new BoundingBox(this.iAtoms);
  		}
  
  		this.jAtoms = Calc.atomsToPoints(jAtoms);
  		this.jAtomObjects = jAtoms;
  
  		if (jAtoms==iAtoms) {
  			this.jbounds=ibounds;
  		} else {
  			if (jcoordbounds!=null) {
  				this.jbounds = jcoordbounds;
  			} else {
  				this.jbounds = new BoundingBox(this.jAtoms);
  
  			}
  		}
  
  		fillGrid();
  	}
docs: Adds the i and j atoms and fills the grid, passing their bounds (array of size 6 with x,y,z minima and x,y,z maxima)
  This way the bounds don't need to be recomputed.
  Subsequent call to {@link #getIndicesContacts()} or {@link #getAtomContacts()} will produce the interatomic contacts.
  @param iAtoms
  @param icoordbounds
  @param jAtoms
  @param jcoordbounds