public AssetSwap(bool parAssetSwap,
Bond bond,
double bondCleanPrice,
double nonParRepayment,
double gearing,
IborIndex iborIndex,
double spread = 0.0,
DayCounter floatingDayCount = null,
Date dealMaturity = null,
bool payBondCoupon = false)
: base(2)
{
bond_ = bond;
bondCleanPrice_ = bondCleanPrice;
nonParRepayment_ = nonParRepayment;
spread_ = spread;
parSwap_ = parAssetSwap;
Schedule tempSch = new Schedule(bond_.settlementDate(),
bond_.maturityDate(),
iborIndex.tenor(),
iborIndex.fixingCalendar(),
iborIndex.businessDayConvention(),
iborIndex.businessDayConvention(),
DateGeneration.Rule.Backward,
false); // endOfMonth
if (dealMaturity == null)
{
dealMaturity = bond_.maturityDate();
}
Utils.QL_REQUIRE(dealMaturity <= tempSch.dates().Last(), () =>
"deal maturity " + dealMaturity +
" cannot be later than (adjusted) bond maturity " +
tempSch.dates().Last());
Utils.QL_REQUIRE(dealMaturity > tempSch.dates()[0], () =>
"deal maturity " + dealMaturity +
" must be later than swap start date " +
tempSch.dates()[0]);
// the following might become an input parameter
BusinessDayConvention paymentAdjustment = BusinessDayConvention.Following;
Date finalDate = tempSch.calendar().adjust(dealMaturity, paymentAdjustment);
Schedule schedule = tempSch.until(finalDate);
// bondCleanPrice must be the (forward) clean price
// at the floating schedule start date
upfrontDate_ = schedule.startDate();
double dirtyPrice = bondCleanPrice_ +
bond_.accruedAmount(upfrontDate_);
double notional = bond_.notional(upfrontDate_);
/* In the market asset swap, the bond is purchased in return for
* payment of the full price. The notional of the floating leg is
* then scaled by the full price. */
if (!parSwap_)
{
notional *= dirtyPrice / 100.0;
}
if (floatingDayCount == null)
{
legs_[1] = new IborLeg(schedule, iborIndex)
.withSpreads(spread)
.withGearings(gearing)
.withNotionals(notional)
.withPaymentAdjustment(paymentAdjustment);
}
else
{
legs_[1] = new IborLeg(schedule, iborIndex)
.withSpreads(spread)
.withGearings(gearing)
.withPaymentDayCounter(floatingDayCount)
.withNotionals(notional)
.withPaymentAdjustment(paymentAdjustment);
}
foreach (CashFlow c in legs_[1])
{
c.registerWith(update);
}
List <CashFlow> bondLeg = bond_.cashflows();
// skip bond redemption
int i;
for (i = 0; i < bondLeg.Count && bondLeg[i].date() <= dealMaturity; ++i)
{
// whatever might be the choice for the discounting engine
// bond flows on upfrontDate_ must be discarded
bool upfrontDateBondFlows = false;
if (!bondLeg[i].hasOccurred(upfrontDate_, upfrontDateBondFlows))
{
legs_[0].Add(bondLeg[i]);
}
}
// if the first skipped cashflow is not the redemption
// and it is a coupon then add the accrued coupon
if (i < bondLeg.Count - 1)
{
Coupon c = bondLeg[i] as Coupon;
if (c != null)
{
CashFlow accruedCoupon = new SimpleCashFlow(c.accruedAmount(dealMaturity), finalDate);
legs_[0].Add(accruedCoupon);
}
}
// add the nonParRepayment_
CashFlow nonParRepaymentFlow = new SimpleCashFlow(nonParRepayment_, finalDate);
legs_[0].Add(nonParRepaymentFlow);
Utils.QL_REQUIRE(!legs_[0].empty(), () => "empty bond leg to start with");
// special flows
if (parSwap_)
{
// upfront on the floating leg
double upfront = (dirtyPrice - 100.0) / 100.0 * notional;
CashFlow upfrontCashFlow = new SimpleCashFlow(upfront, upfrontDate_);
legs_[1].Insert(0, upfrontCashFlow);
// backpayment on the floating leg
// (accounts for non-par redemption, if any)
double backPayment = notional;
CashFlow backPaymentCashFlow = new SimpleCashFlow(backPayment, finalDate);
legs_[1].Add(backPaymentCashFlow);
}
else
{
// final notional exchange
CashFlow finalCashFlow = new SimpleCashFlow(notional, finalDate);
legs_[1].Add(finalCashFlow);
}
Utils.QL_REQUIRE(!legs_[0].empty(), () => "empty bond leg");
foreach (CashFlow c in legs_[0])
{
c.registerWith(update);
}
if (payBondCoupon)
{
payer_[0] = -1.0;
payer_[1] = +1.0;
}
else
{
payer_[0] = +1.0;
payer_[1] = -1.0;
}
}
public void visit(Coupon c)
{
// nothing to do
}
public override void initialize(FloatingRateCoupon coupon)
{
coupon_ = coupon as CmsCoupon;
Utils.QL_REQUIRE(coupon_ != null, () => "CMS coupon needed");
gearing_ = coupon_.gearing();
spread_ = coupon_.spread();
fixingDate_ = coupon_.fixingDate();
paymentDate_ = coupon_.date();
swapIndex_ = coupon_.swapIndex();
forwardCurve_ = swapIndex_.forwardingTermStructure();
if (swapIndex_.exogenousDiscount())
{
discountCurve_ = swapIndex_.discountingTermStructure();
}
else
{
discountCurve_ = forwardCurve_;
}
// if no coupon discount curve is given just use the discounting curve
// from the swap index. for rate calculation this curve cancels out in
// the computation, so e.g. the discounting swap engine will produce
// correct results, even if the couponDiscountCurve is not set here.
// only the price member function in this class will be dependent on the
// coupon discount curve.
today_ = QLCore.Settings.Instance.evaluationDate();
if (paymentDate_ > today_ && !couponDiscountCurve_.empty())
{
couponDiscountRatio_ = couponDiscountCurve_.link.discount(paymentDate_) /
discountCurve_.link.discount(paymentDate_);
}
else
{
couponDiscountRatio_ = 1.0;
}
spreadLegValue_ = spread_ * coupon_.accrualPeriod() *
discountCurve_.link.discount(paymentDate_) *
couponDiscountRatio_;
if (fixingDate_ > today_)
{
swapTenor_ = swapIndex_.tenor();
swap_ = swapIndex_.underlyingSwap(fixingDate_);
swapRateValue_ = swap_.fairRate();
annuity_ = 1.0E4 * Math.Abs(swap_.fixedLegBPS());
SmileSection sectionTmp = swaptionVolatility().link.smileSection(fixingDate_, swapTenor_);
// adjust bounds by section's shift
shiftedLowerBound_ = settings_.lowerRateBound_ - sectionTmp.shift();
shiftedUpperBound_ = settings_.upperRateBound_ - sectionTmp.shift();
// if the section does not provide an atm level, we enhance it to
// have one, no need to exit with an exception ...
if (sectionTmp.atmLevel() == null)
{
smileSection_ = new AtmSmileSection(sectionTmp, swapRateValue_);
}
else
{
smileSection_ = sectionTmp;
}
// compute linear model's parameters
double gx = 0.0, gy = 0.0;
for (int i = 0; i < swap_.fixedLeg().Count; i++)
{
Coupon c = swap_.fixedLeg()[i] as Coupon;
double yf = c.accrualPeriod();
Date d = c.date();
double pv = yf * discountCurve_.link.discount(d);
gx += pv * GsrG(d);
gy += pv;
}
double gamma = gx / gy;
Date lastd = swap_.fixedLeg().Last().date();
a_ = discountCurve_.link.discount(paymentDate_) *
(gamma - GsrG(paymentDate_)) /
(discountCurve_.link.discount(lastd) * GsrG(lastd) +
swapRateValue_ * gy * gamma);
b_ = discountCurve_.link.discount(paymentDate_) / gy -
a_ * swapRateValue_;
}
}
