code: @Override
  	public double varianceOfStockPrice(double time) {
  		return Math.pow(initialValue, 2) * Math.exp(2 * riskFreeRate * time)
  				* (Math.exp(Math.pow(volatility, 2) * time) - 1);
  	}
docs: /* (non-Javadoc)
  @see net.finmath.finitedifference.models.FiniteDifference1DModel#varianceOfStockPrice(double)