final double maturity = rfdc.yearFraction(referenceDate, maturityDate);
final StochasticProcess1D bs = new GeneralizedBlackScholesProcess(process.stateVariable(), flatDividends, flatRiskFree, flatVol);
final TimeGrid grid = new TimeGrid(maturity, timeSteps);
final Tree tree = (Tree)getTreeInstance(bs, maturity, timeSteps, payoff.strike());
final BlackScholesDividendLattice<Tree> lattice = new BlackScholesDividendLattice<Tree>(tree, rRate, maturity, timeSteps,
rfdc, grid, referenceDate, a.cashFlow);
final DiscretizedVanillaOption option = new DiscretizedVanillaOption(a, process, grid);