private void BuildYieldCurve()
        {
            //Extract the rates from the xml
            var xDoc = XElement.Load("Curve.xml");

            var helpers = new RateHelperVector();

            AddDeposits(xDoc, helpers);
            AddBonds(xDoc, helpers);
            AddSwaps(xDoc, helpers);

            yieldCurve = new PiecewiseFlatForward(Settings.instance().getEvaluationDate(), helpers, new ActualActual(ActualActual.Convention.Bond));
            yieldCurve.enableExtrapolation();
        }