*/
    private void constrainZeroOneVars(LinearProgram lp) {	// set the indicator variables to be integral, and to be	// between zero and one (we need extra constraints since there	// isn't a "boolean" var type in the interace.)	for (int i=0; i<nodes.size(); i++) {	    for (int j=0; j<numTiles; j++) {		lp.setBoolVar(pNum(i, j));		// P_i,j >= 0		double[] con = lp.getEmptyConstraint();		con[pNum(i,j)] = 1;		lp.addConstraintGE(con, 0);		// P_i,j <= 1		con = lp.getEmptyConstraint();		con[pNum(i,j)] = -1;		lp.addConstraintGE(con, -1);	    }	}    }