sandbox/PassThroughOAS.R

In glennmschultz/BondLab: BondLab is a package for the analysis of fixed-income securities

  # Bond Lab is a software application for the analysis of 
  # fixed income securities it provides a suite of applications
  # mortgage backed, asset backed securities, and commerical mortgage backed 
  # securities Copyright (C) 2016  Bond Lab Technologies, Inc.
  # 
  # This program is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  # 
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with this program.  If not, see <http://www.gnu.org/licenses/>.

  #' @include MBSDetails.R MortgageCashFlow.R MortgageOAS.R
  NULL
  
  #' An S4 class containing the classes MBSDetails, MortgageCashFlow, 
  #' and MortgageOAS
  #' 
  #' @exportClass PassThroughOAS
  setClass("PassThroughOAS",
         representation(),
         contains = c("MBSDetails", 
                      "MortgageCashFlow", 
                      "MortgageOAS"))


  setGeneric("PassThroughOAS", function(bond.id = "character", 
                                      trade.date = "character", 
                                      settlement.date = "character", 
                                      original.bal = numeric(), 
                                      price = numeric(), 
                                      sigma = numeric(), 
                                      paths = numeric())
  {standardGeneric("PassThroughOAS")})
  
  setMethod("initialize",
          signature("PassThroughOAS"),
          function(.Object,
                   ...)
          {callNextMethod(.Object,
            ...)
          })


  #' The constructor function for the passthrough OAS object 
  #' 
  #' This function is the Pass Through OAS constructor function
  #' @param bond.id A character string the MBS cusip number
  #' @param trade.date A character string the trade date
  #' @param settlement.date A character string the settlement date
  #' @param original.bal A numeric value the original balance traded
  #' @param price A numeric value the trade price
  #' @param sigma A numeric value interest rate volatility assumption
  #' @param paths A numeric value the number of simulated paths
  #' @examples 
  #' \dontrun{
  #' PassThroughOAS(bond.id = "bondlabMBS4", trade.date = "01-10-2013", 
  #' settlement.date = "01-13-2013", 
  #' original.bal = 100000, price = 105.75, sigma = 0.015, paths = 200)} 
  #' @export PassThroughOAS
  PassThroughOAS <- function(bond.id = "character", 
                           trade.date = "character", 
                           settlement.date = "character", 
                           original.bal = numeric(), 
                           price = numeric(), 
                           sigma = numeric(), 
                           paths = numeric()){
  
  #Error Trap Settlement Date and Trade Date order.  
  #This is not done in the Error Trap Function because that function is 
  #to trap errors in bond information that is passed into the functions.  
  #It is trapped here because this is the first use of trade date
  if(trade.date > settlement.date) stop ("Trade Date Must be less than settlement date")
  
                        
  Rate.Delta = rate.delta
  
  #The first step is to read in the Bond Detail, rates, and Prepayment Model Tuning Parameters
  bond.id <- MBS(MBS.id = as.character(bond.id))
  Burnout <- bond.id@Burnout
  
  #Call the desired curve from rates data folder
  rates.data <- Rates(trade.date = trade.date)
  short.rate <- as.numeric(rates.data[1,2])/yield.basis
  
  #Call Mortgage Rate Functions
  MortgageRate <- MtgRate()
    
  #Call Prepayment Model Tuning Parameters
  ModelTune <- ModelTune(bond.id = bond.id)
  
  #This section begins standard bond analysis based on the term structure fit from
  #The CIR Model Term Structure 0 volatiltiy assumption
  issue.date = as.Date(bond.id@IssueDate, "%m-%d-%Y")
  start.date = as.Date(bond.id@DatedDate, "%m-%d-%Y")
  end.date = as.Date(bond.id@Maturity, "%m-%d-%Y")
  lastpmt.date = as.Date(bond.id@LastPmtDate, "%m-%d-%Y")
  nextpmt.date = as.Date(bond.id@NextPmtDate, "%m-%d-%Y")
  coupon = bond.id@Coupon
  frequency = bond.id@Frequency
  delay = bond.id@PaymentDelay
  factor = bond.id@MBSFactor
  settlement.date = as.Date(c(settlement.date), "%m-%d-%Y")
  bondbasis = bond.id@BondBasis
  
  pmtdate.interval = months.in.year/frequency
  
  #Compute the payment dates 
  pmtdate = as.Date(c(if(settlement.date == issue.date) 
  {seq(start.date, end.date, by = paste(pmtdate.interval, "months"))} 
  else 
  {seq(nextpmt.date, end.date, by = paste(pmtdate.interval, 
                                          "months"))}), "%m-%d-%Y") + delay
  
  time.period <- BondBasisConversion(issue.date = issue.date, 
                                    start.date = start.date, 
                                    end.date = end.date, 
                                    settlement.date = settlement.date,
                                    lastpmt.date = lastpmt.date, 
                                    nextpmt.date = pmtdate,
                                    type = bondbasis)
  
  #Compute the payment dates 
  pmtdate = as.Date(c(if(settlement.date == issue.date) 
  {seq(start.date, end.date, by = paste(pmtdate.interval, "months"))} 
  else 
  {seq(nextpmt.date, end.date, by = paste(pmtdate.interval, 
                                          "months"))}), "%m-%d-%Y") + delay
  
  #Count the number of cashflows 
  #num.periods is the total number of cashflows to be received
  #num.period is the period in which the cashflow is received
  num.periods = length(time.period)
  num.period = seq(1:num.periods)
  
  #Call OAS Term Strucuture to Pass to the Prepayment Model 

  Market.Fit <- CalibrateCIR(trade.date = trade.date, sigma = sigma)
  kappa  = Market.Fit$p1
  lambda = Market.Fit$p2
  theta  = Market.Fit$p3
  
#  Sim.Rate <- CIRSim(shortrate = short.rate,
#                      kappa = kappa,
#                      theta = theta,
#                      T = ((num.periods-1) / months.in.year),
#                      step = 1/months.in.year,
#                      sigma = 0,
#                      N = 1)
  
#  #Compute the continuously compounded rate
#  Compounded.Rate <- cumprod(1 + Sim.Rate)
  
#  #Compute the Spot Rate
#  Spot.Rate <- (((Compounded.Rate ^ (1/ time.period))^(1/months.in.year))-1)
#  Two.Year.Fwd <- as.vector(CIRBondPrice(shortrate = as.numeric(Sim.Rate), 
#                                      kappa = kappa, 
#                                      lambda = lambda, 
#                                      theta = theta, 
#                                      sigma = 0, 
#                                      T = 2, 
#                                      step = 0, 
#                                      result = "y") * yield.basis)
  
#  Ten.Year.Fwd <- as.vector(CIRBondPrice(shortrate = as.numeric(Sim.Rate), 
#                                      kappa = kappa, 
#                                      lambda = lambda, 
#                                      theta = theta, 
#                                      sigma = 0, 
#                                      T = 10, 
#                                      step = 0, 
#                                      result = "y") * yield.basis)
  CIRSpot <- CIRBondPrice(
    shortrate = short.rate,
    T = 40,
    step = 1/months.in.year,
    kappa = kappa,
    lambda = lambda,
    theta = theta,
    sigma = sigma,
    result = "y")
  
  time.period <- seq(from = 1, to = 30, by = 1)
  time.period <- time.period/12
  timelength <- length(time.period)
  
  CIRSpot[1] <- short.rate
  Mo1Fwd <- Forward.Rate(SpotRate.Curve = CIRSpot, FwdRate.Tenor = 1)
  TwoYrFwd <-Forward.Rate(SpotRate.Curve = CIRSpot, FwdRate.Tenor = 2)
  TenYrFwd <-Forward.Rate(SpotRate.Curve = CIRSpot, FwdRate.Tenor = 10)
  

  TermStructure <- new("TermStructure",
                       TradeDate = trade.date,
                       Period = time.period[2:timelength],
                       Date = unname(as.character(pmtdate)),
                       SpotRate = CIRSpot * 100,
                       ForwardRate = Mo1Fwd * 100,
                       TwoYearFwd = TwoYrFwd * 100,
                       TenYearFwd = TenYrFwd * 100)
  
  #Third if mortgage security call the prepayment model
  PrepaymentAssumption <- PrepaymentModel(bond.id = bond.id, 
                                               MortgageRate = MortgageRate, 
                                               TermStructure = TermStructure, 
                                               PrepaymentAssumption = "MODEL", 
                                               ModelTune = ModelTune, 
                                               Burnout = Burnout)
  
  #The fourth step is to call the bond cusip details and calculate 
  #Bond Yield to Maturity, Duration, Convexity and CashFlow.
  MortgageCashFlow <- MortgageCashFlow(bond.id = bond.id, 
                                       original.bal = original.bal, 
                                       settlement.date = settlement.date, 
                                       price = price, 
                                       PrepaymentAssumption = PrepaymentAssumption)

  
  #This section begins the OAS analysis
  MortgageOAS  <- Mortgage.OAS(bond.id = bond.id@ID, 
                               trade.date = trade.date, 
                               settlement.date = settlement.date, 
                               original.bal = original.bal, 
                               price = price, 
                               sigma = sigma, 
                               paths = paths) 

  
  new("PassThroughOAS",
      Cusip = Cusip(bond.id),
      ID = ID(bond.id),
      BondType = BondType(bond.id),
      Sector = Sector(bond.id),
      Coupon = Coupon(bond.id),
      IssueDate = IssueDate(bond.id),
      DatedDate = DatedDate(bond.id),
      Maturity = Maturity(bond.id),
      LastPmtDate = LastPmtDate(bond.id),
      NextPmtDate = NextPmtDate(bond.id),
      Term = Term(bond.id),
      WALA = WALA(bond.id),
      WAM = WAM(bond.id),
      PaymentDelay = PaymentDelay(bond.id),
      Moody = MoodyRating(bond.id),
      SP = SPRating(bond.id),
      BondLab  = BondLabRating(bond.id),
      Frequency = Frequency(bond.id),
      BondBasis = BondBasis(bond.id),
      GWac = GWac(bond.id),
      OrigLoanBal = OrigLoanBal(bond.id),
      OrigLTV = OrigLTV(bond.id),
      AmortizationType = AmortizationType(bond.id),
      AmortizationTerm = AmortizationTerm(bond.id),
      Index = Index(bond.id),
      Margin = Margin(bond.id),
      FirstPmtDate = FirstPmtDate(bond.id),
      FinalPmtDate = FinalPmtDate(bond.id),
      Servicing = Servicing(bond.id),
      PMI = PMI(bond.id),
      InitialInterest = InitialInterest(bond.id),
      InterestOnlyPeriod = InterestOnlyPeriod(bond.id),
      FirstPrinPaymentDate = FirstPrinPaymentDate(bond.id),
      BalloonPmt = BalloonPmt(bond.id),
      BalloonDate = BalloonDate(bond.id),
      MBSFactor = MBSFactor(bond.id),
      OriginalBal = MBSFactor(bond.id),
      CurrentBal = OrigLTV(bond.id),
      Model = Model(bond.id),
      Burnout = BurnOut(bond.id),
      SATO = SATO(bond.id),
      Price = Price(MortgageCashFlow),
      Accrued = Accrued(MortgageCashFlow),
      YieldToMaturity = YieldToMaturity(MortgageCashFlow),
      WAL = WAL(MortgageCashFlow),
      ModDuration = ModDuration(MortgageCashFlow),
      Convexity = Convexity(MortgageCashFlow),
      Period = Period(MortgageCashFlow),
      PmtDate = PmtDate(MortgageCashFlow),
      TimePeriod = TimePeriod(MortgageCashFlow),
      BeginningBal = BeginningBal(MortgageCashFlow),
      MonthlyPmt = MonthlyPmt(MortgageCashFlow),
      MonthlyInterest = MonthlyInterest(MortgageCashFlow),
      PassThroughInterest = PassThroughInterest(MortgageCashFlow),
      ScheduledPrin = ScheduledPrin(MortgageCashFlow),
      PrepaidPrin = PrepaidPrin(MortgageCashFlow),
      DefaultedPrin = DefaultedPrin(MortgageCashFlow),
      LossAmount = LossAmount(MortgageCashFlow),
      RecoveredAmount = RecoveredAmount(MortgageCashFlow),
      EndingBal = EndingBalance(MortgageCashFlow),
      ServicingIncome = ServicingIncome(MortgageCashFlow),
      PMIPremium = PMIPremium(MortgageCashFlow),
      GFeePremium = GFeePremium(MortgageCashFlow),  
      TotalCashFlow = TotalCashFlow(MortgageCashFlow),
      OAS = OAS(MortgageOAS),
      ZeroVolSpread = ZeroVolSpread(MortgageOAS),
      SpreadToCurve = SpreadToCurve(MortgageOAS),
      EffDuration = EffDuration(MortgageOAS),
      EffConvexity = EffConvexity(MortgageOAS),
      KeyRateTenor = KeyRateTenor(MortgageOAS),
      KeyRateDuration = KeyRateDuration(MortgageOAS),
      KeyRateConvexity = KeyRateConvexity(MortgageOAS),
      PriceDist = PriceDist(MortgageOAS),
      PathSpread = PathSpread(MortgageOAS),
      PathWAL = PathWAL(MortgageOAS),
      PathModDur = PathModDur(MortgageOAS),
      PathYTM = PathYTM(MortgageOAS))
  }