if (EAGER && eq.evaluate()) changedCell(lhs);
  void newEquation (OPT_DF_LatticeCell lhs, OPT_DF_Operator operator,       OPT_DF_LatticeCell op1) {    // add to the list of equations    OPT_DF_Equation eq = new OPT_DF_Equation(lhs, operator, op1);    equations.addGraphNode(eq);    equations.addGraphNode(op1);    newEquations.add(eq);    // add lattice cells for the operands to the working solution    //       cells.put(lhs.getKey(),lhs);    //       cells.put(op1.getKey(),op1);    op1.addUse(eq);    lhs.addDef(eq);  }