QuantLib: a free/open-source library for quantitative finance
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tenoroptionletvts.cpp
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1/* -*- mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2
3/*
4Copyright (C) 2018 Sebastian Schlenkrich
5
6This file is part of QuantLib, a free-software/open-source library
7for financial quantitative analysts and developers - http://quantlib.org/
8
9QuantLib is free software: you can redistribute it and/or modify it
10under the terms of the QuantLib license. You should have received a
11copy of the license along with this program; if not, please email
12<quantlib-dev@lists.sf.net>. The license is also available online at
13<http://quantlib.org/license.shtml>.
14
15This program is distributed in the hope that it will be useful, but WITHOUT
16ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17FOR A PARTICULAR PURPOSE. See the license for more details.
18*/
19
20/*! \file tenoroptionletvts.cpp
21 \brief caplet volatility term structure based on volatility transformation
22*/
23
24#include <ql/exercise.hpp>
27#include <ql/math/rounding.hpp>
30#include <ql/time/schedule.hpp>
31#include <utility>
32
33
34namespace QuantLib {
35
37 ext::shared_ptr<IborIndex> baseIndex,
38 ext::shared_ptr<IborIndex> targIndex,
39 ext::shared_ptr<CorrelationStructure> correlation)
40 : OptionletVolatilityStructure(baseVTS->referenceDate(),
41 baseVTS->calendar(),
42 baseVTS->businessDayConvention(),
43 baseVTS->dayCounter()),
44 baseVTS_(baseVTS), baseIndex_(std::move(baseIndex)), targIndex_(std::move(targIndex)),
45 correlation_(std::move(correlation)) {
46 QL_REQUIRE(baseIndex_->tenor().frequency() % targIndex_->tenor().frequency() == 0,
47 "Base index frequency must be a multiple of target tenor frequency");
48 }
49
50
52 const TenorOptionletVTS& volTS, const Time optionTime)
53 : SmileSection(optionTime, volTS.baseVTS_->dayCounter(), Normal, 0.0),
55 // we assume that long (target) tenor is a multiple of short (base) tenor
56 // first we need the long tenor start and end date
57 Real oneDayAsYear =
58 volTS.dayCounter().yearFraction(volTS.referenceDate(), volTS.referenceDate() + 1);
60 volTS.referenceDate() + ((BigInteger)ClosestRounding(0)(optionTime / oneDayAsYear));
61 Date effectiveDate = volTS.baseIndex_->fixingCalendar().advance(
62 exerciseDate, volTS.baseIndex_->fixingDays() * Days);
63 Date maturityDate = volTS.baseIndex_->fixingCalendar().advance(
64 effectiveDate, volTS.targIndex_->tenor(), Unadjusted, false);
65 // now we can set up the short tenor schedule
66 Schedule baseFloatSchedule(effectiveDate, maturityDate, volTS.baseIndex_->tenor(),
67 volTS.baseIndex_->fixingCalendar(), ModifiedFollowing,
69 // set up scalar attributes
70 fraRateTarg_ = volTS.targIndex_->fixing(exerciseDate);
71 Time yfTarg = volTS.targIndex_->dayCounter().yearFraction(effectiveDate, maturityDate);
72 for (Size k = 0; k < baseFloatSchedule.dates().size() - 1; ++k) {
73 Date startDate = baseFloatSchedule.dates()[k];
74 Date fixingDate = volTS.baseIndex_->fixingCalendar().advance(
75 startDate, (-1 * volTS.baseIndex_->fixingDays()) * Days);
76 Time yearFrac = volTS.baseIndex_->dayCounter().yearFraction(
77 baseFloatSchedule.dates()[k], baseFloatSchedule.dates()[k + 1]);
78 // set up vector attributes
79 baseSmileSection_.push_back(volTS.baseVTS_->smileSection(fixingDate, true));
80 startTimeBase_.push_back(
81 volTS.dayCounter().yearFraction(volTS.referenceDate(), startDate));
82 fraRateBase_.push_back(volTS.baseIndex_->fixing(fixingDate));
83 v_.push_back(yearFrac / yfTarg * (1.0 + yfTarg * fraRateTarg_) /
84 (1.0 + yearFrac * fraRateBase_[k]));
85 }
86 }
87
89 Real sum_v = 0.0;
90 for (Real k : v_)
91 sum_v += k;
92 std::vector<Real> volBase(v_.size());
93 for (Size k = 0; k < fraRateBase_.size(); ++k) {
94 Real strike_k = (strike - (fraRateTarg_ - sum_v * fraRateBase_[k])) / sum_v;
95 volBase[k] = baseSmileSection_[k]->volatility(strike_k, Normal, 0.0);
96 }
97 Real var = 0.0;
98 for (Size i = 0; i < volBase.size(); ++i) {
99 var += v_[i] * v_[i] * volBase[i] * volBase[i];
100 for (Size j = i + 1; j < volBase.size(); ++j) {
101 Real corr = (*correlation_)(startTimeBase_[i], startTimeBase_[j]);
102 var += 2.0 * corr * v_[i] * v_[j] * volBase[i] * volBase[j];
103 }
104 }
105 Real vol = sqrt(var);
106 return vol;
107 }
108
109
110}
const Real correlation_
Closest rounding.
Definition: rounding.hpp:106
Concrete date class.
Definition: date.hpp:125
Time yearFraction(const Date &, const Date &, const Date &refPeriodStart=Date(), const Date &refPeriodEnd=Date()) const
Returns the period between two dates as a fraction of year.
Definition: daycounter.hpp:128
Shared handle to an observable.
Definition: handle.hpp:41
Optionlet (caplet/floorlet) volatility structure.
Payment schedule.
Definition: schedule.hpp:40
const std::vector< Date > & dates() const
Definition: schedule.hpp:75
interest rate volatility smile section
virtual const Date & exerciseDate() const
std::vector< ext::shared_ptr< SmileSection > > baseSmileSection_
Volatility volatilityImpl(Rate strike) const override
TenorOptionletSmileSection(const TenorOptionletVTS &volTS, Time optionTime)
TenorOptionletVTS(const Handle< OptionletVolatilityStructure > &baseVTS, ext::shared_ptr< IborIndex > baseIndex, ext::shared_ptr< IborIndex > targIndex, ext::shared_ptr< CorrelationStructure > correlation)
ext::shared_ptr< IborIndex > targIndex_
Handle< OptionletVolatilityStructure > baseVTS_
ext::shared_ptr< IborIndex > baseIndex_
virtual const Date & referenceDate() const
the date at which discount = 1.0 and/or variance = 0.0
virtual DayCounter dayCounter() const
the day counter used for date/time conversion
date generation rule
discounting swap engine
#define QL_REQUIRE(condition, message)
throw an error if the given pre-condition is not verified
Definition: errors.hpp:117
Option exercise classes and payoff function.
Real Time
continuous quantity with 1-year units
Definition: types.hpp:62
QL_REAL Real
real number
Definition: types.hpp:50
QL_BIG_INTEGER BigInteger
large integer number
Definition: types.hpp:39
Real Volatility
volatility
Definition: types.hpp:78
Real Rate
interest rates
Definition: types.hpp:70
std::size_t Size
size of a container
Definition: types.hpp:58
base class for Inter-Bank-Offered-Rate indexes
Definition: any.hpp:35
STL namespace.
Rounding implementation.
date schedule
caplet volatility term structure based on volatility transformation