Business Functions Library for Excel

Function Reference Home Date and Time Calculations Introduction Date Information Introduction DYear DMonth DateYMD DateSeqNum IsSeqDate DayName MonthName IsLeap DaysInMonth IsAnniversary WeekNumber WeekNumberToDate MonthStart MonthEnd NumPers MostRecent MostImminent TimeBaseLengths AnnSeq CreateTimeBase Date Difference Introduction DiffY DiffM DiffD DiffP Date Increment Introduction DpY DpM DpD DpP PrevDateSeq NextDateSeq PrevDateList NextDateList NextDateCombine DatePer EDateBF DateSeq DateSeqCombine Time Period Introduction TpY TpM TpD Occurs Special Dates Introduction Business Days Introduction DpYBD DpMBD DpDBD NextBD PrevBD NextDateSeqBD PrevDateSeqBD IsBD NetWorkDaysBF NextDateListBD PrevDateListBD Holidays Introduction Holiday DescribeHol WhatHol IsHol IsWE WesternEaster CreateDate Discrete Amount Projections Introduction Payments Introduction MkPmtsSeq MkPmts MkPmtsGrow MkPmtsFcst MkPmtsSF MkPmtsLim MkPmtsLag MkPmtsLagProf RePhasePmts TotPmts TotPmtsSF SumBetween DoBetween MatchPmts CarryNeg CarryPos MkPmtsX MkPmtsLagX MkPmtsIdx MkPmtsCats MkPmtsGroup Payments Periodic Introduction MkPmtsPer MkPmtsPerGrow MkPmtsPerFcst MkPmtsIdxPer Payments Market Introduction MkPmtsGrowMkt MkPmtsFcstMkt MkPmtsPerGrowMkt MkPmtsPerFcstMkt Distributed Amount Projections Introduction Time Spread Introduction GSpread UniSpread UniSpreadGrow SCurve SCurveGrow DistSpread FStepSpread TStepSpread MkPmtsWeighted SCumCurve Time Spread Periodic Introduction UniSpreadPer SCurvePer SCurveGrowPer UniSpreadGrowPer Time Spread Weighted Introduction WeightSpread FWeightSpread TWeightSpread Time Spread History Introduction UniSpreadH SCurveH WeightSpreadH FWeightSpreadH TWeightSpreadH DistSpreadH GSpreadH UniSpreadAdj SCurveAdj WeightSpreadAdj FWeightSpreadAdj TWeightSpreadAdj DistSpreadAdj GSpreadAdj Constant Rate Projections Introduction Constant Rate Introduction Con ConGrow AnnGrow RePhaseCon AnnRate ConSF ConIdx ConEvent Constant Rate Periodic Introduction ConPer AnnGrowPer ConGrowPer Constant Rate Market Introduction ConGrowMkt ConFcstMkt ConFcstGrowMkt Constant Rate Revenue Introduction ConRevGrow2 ConRev ConRevGrow ConRevFcst Stepped Rate Projections Introduction Stepped Rate From Introduction FStep FStepGrow FStepGrowX FStepThenGrow FStepFcst FStepGrown FStepSF FStepCombine MultiFStep Stepped Rate To Introduction TStep TStepGrow TStepGrowX TStepThenGrow TStepFcst TStepGrown TStepSF TStepCombine MultiTStep Stepped Rate Market Introduction FStepGrowMkt FStepFcstMkt TStepGrowMkt TStepFcstMkt Stepped Rate Revenue Introduction FStepRev TStepRev FStepRevGrow FStepRevFcst TStepRevGrow TStepRevFcst FStepThenGrowRev TStepThenGrowRev Interpolated and Curve-Fitted Projections Introduction Interpolated and Curve-Fitted Rates Introduction FittedRate Ramp Interpolated and Curve-Fitted Levels Introduction InterpedLevel FittedLevel Instantaneous Level Projections Introduction Levels Introduction Bal Level FLevels TLevels FLevelsGrow TLevelsGrow FLevelsFcst TLevelsFcst FLevelsCombine FLevelsThenGrow TLevelsThenGrow Levels Market Introduction FLevelsGrowMkt TLevelsGrowMkt FLevelsFcstMkt TLevelsFcstMkt Growth Introduction Grow GrowFromTo FGrowStep TGrowStep FGrowStepMkt TGrowStepMkt GrowMkt GrowLin Forecast Introduction Fcst FcstGrow FcstCollar SumFcst FFcstStep TFcstStep IdxFromTo Forecast Specific Times Introduction FcstT TFcstT Levels Over Time Projections Introduction Levels Average Introduction ALevel FALevels TALevels FALevelsGrow TALevelsGrow FALevelsFcst TALevelsFcst FALevelsThenGrow TALevelsThenGrow ALevelGrow Levels Average Market Introduction FALevelsGrowMkt TALevelsGrowMkt FALevelsFcstMkt TALevelsFcstMkt Growth Average Introduction AGrow Projections NPV Introduction NPV Constant Rate Introduction PVCon PVAnnGrow PVConGrow PVConQ NPV Stepped Rate Introduction PVTStep PVTStepQ PVTStepIC PVTStepICQ PVFStep PVFStepIC PVFStepQ PVFStepICQ NPV Payments Introduction PVMkPmtsSF PVMkPmts NPV Time Spread Introduction PVGSpread PVUniSpread PVSCurve PVSCurveGrow PVDistSpread PVFStepSpread PVTStepSpread PVMkPmtsWeighted PVSCumCurve Time Value Of Money Analysis Introduction Basic Interest Rate Conversions Introduction SimpleToSimple SimpleToAER SimpleToCont SimpleToDF AERToSimple AERToCont AERToDF ContToSimple ContToAER ContToDF DFToSimple DFToAER DFToCont Advanced Interest Rate Conversions Introduction SimpleToSimpleX SimpleToAERX SimpleToContX SimpleToDFX AERToSimpleX ContToSimpleX DFToSimpleX RateConvert Annuity Introduction FVM PVM PmtM TermM IntRateM PVEGAnn PVEGAnnM PVEGPerAnn PVEGPerp PVEGPerpM PVEGPerPerp SumEGAnn SumEGAnnM SumEGAnnCont SumLGAnn SumLGAnnM SumLGAnnCont Annuity Extended Introduction PVBF PMTBF RateBF US APR Introduction APRToQuoted QuotedToAPR Discounted Cash Flow Introduction DCF One-Off Introduction PVOne FPVOne TPVOne PVOneQ DCF Annual Introduction PVA IRRA PayBackA PayBackDiscA DurationA AvLifeA DCF Even Intervals Introduction PVE IRRE PaybackE PayBackDiscE DurationE AvLifeE DCF Specific Times Introduction PVT IRRT PayBackT PayBackDiscT DurationT AvLifeT PVTIC IRRTIC PVTX IRRTX PVTCX IRRTCX PVTR IRRTR DCF Dispersed Annual Introduction NPVM IRRM CorrectionM CorrectionCont CorrectionDC DurationM AvLifeM EffTimeM Accounting And Tax Introduction Accounting Introduction Depreciate DepreciatedValue DepPoolWIP DepPoolRatio DepPool DepreciatePer DepreciateGrowPer DepreciateFcstPer DepreciateIdxPer LIFOPrice LIFOCalc Tax Introduction FAvRate TAvRate FAvRateTD TAvRateTD Mathematical Calculations Introduction Statistics Introduction LinReg BestPoly SignChanges RSqrdPoly PolyEqn CalcPoly PolyReg Range Operations Introduction Range Lookup Introduction LookupNum LookupN SeekNum PickNum SortPick LookUpNum2D PickMatrix LookupNIndex Seek SeekList SortNum FindIf Range Sum Introduction DoBetweenX SumCat SumCats SumPos SumNeg SumDiv SumBounds SumSubRange SumCombine SelCats Range Reference Introduction Coordinates WorkSheetName RefPlus GetRef Range Calcs Introduction MinBetween MaxBetween MeanNZ WeightAv Range Information Introduction RangeDir Range Manipulation Introduction SortText ApplyToList CombineLists TransposeNum Unique Interpolation Introduction Interp Interpolate InterpDate InterpolateDate Intersection Simulation Modelling Introduction Monte Carlo Introduction Distribution PartialDependency DistCumulative DistUniform DistTriangular DistDoubleTri DistNormal DistLogNormal RandNum NRandom PickRandom DescribeDistType CumProb Real Estate Introduction Rent Introduction RentGrow RentFcst Rent From Introduction FStepRent FStepRentGrow FStepRentFcst FStepRentFcstCollar Rent To Introduction TStepRent TStepRentGrow TStepRentFcst TStepRentGrowCollar TStepRentFcstCollar Rent Reletting Introduction RentFcstR RentGrowR FStepRentGrowR FStepRentFcstR TStepRentGrowR TStepRentFcstR TStepRentGrowSFR FStepRentGrowSFR TStepRentFcstSFR FStepRentFcstSFR UK Valuation Introduction CapValue EqYield CapValueG EqYieldG CapValueGD EqYieldGD NomToTrue TrueToNom YPP YPPDef YPA YPADef CapValueGrowGD CapValueFcstGD EqYieldGrowGD EqYieldFcstGD UK Valuation DCF Introduction CapValueDCF EqYieldDCF CapValueDCFG EqYieldDCFG CapValueDCFGD EqYieldDCFGD NomToTrueDCF TrueToNomDCF YPADefDCF YPPDefDCF TheorYield ImpGrowth ImpDiscRate PVRent TWRR NPV Rent Projections Introduction PVRentGrow PVRentFcst PVTStepRent PVTStepRentGrow PVTStepRentFcst PVTStepRentGrowR PVTStepRentFcstR PVTStepRentGrowIC PVTStepRentGrowRIC PVTStepIdxRentGrowR PVTStepIdxRentFcstR Retail Rent Introduction TStepGTurnRentGrow TStepGTurnRentGrowR Index Rent Introduction IdxRentGrowR IdxRentFcstR IdxRentGrowMktR IdxRentFcstMktR TStepIdxRentGrowR TStepIdxRentFcstR Real Estate Costs Introduction LetCostR LetCostRQ LeasingFeeGrowR FServChargeR ServChargeGrowR ServChargeFcstR FServChargeGrowR FVacServChargeR VacServChargeGrowR VacServChargeFcstR LeasingFeeFcstR Real Estate Costs UK Introduction UKRatesGrow UKRatesFcst UKRatesGrowR UKRatesFcstR UKEmptyRatesFcstR UKEmptyRatesGrowR Lease Information Introduction LeaseEnd ReletOccurs RentDateInfo RentEventOccurs RentEvent LastReview NextReview LastReviewR NextReviewR LeaseInfo Occupancy LeaseDates Banking Introduction Interest Introduction Interest FInterest TInterest TotInterestSF InterestX PVFInterest PVInterestX PVInterest Yield Curve Introduction ZeroCoupon FutureToSpot SpotToSpot Loan Introduction Loan LoanX LoanLin LoanLinX Mortgage MortgageQ LoanPool MortgagePool IdxBondGrow IdxBondFcst Residual Cash Introduction Overdraft CashAcct FlexAcct CurrentAcct STDAcct LoanAcct LoanAcctEM Equity Trading Introduction BetaIndex BetaReturns DescribeReturn TotalReturn Options Introduction OptionBS OptionBinom OptionMonte Petroleum Economics Introduction Petroleum Engineering Introduction STOIIP Decline Curve Introduction Decline DeclineRate DescribeDecline ProdProf AbandonDate StartDecline Text Introduction Numbers To Text Introduction MoneyText Text String Introduction GetToken GetTokens InString ExInt ExFl Miscellaneous Introduction Special Arithmetic Introduction StdEq DiffGaps AddGaps Rounding Introduction SRound SFloor SCeiling RoundWeekDay RoundMonthDay RoundMD RoundDateSeq DateRound DateFloor DateCeiling Disperse RoundList Library Information Introduction BFVer DescribeLoanAcctOutput DescribeCombineSwitch DescribePmtsPerYear DescribeLevelSwitch DescribeBD DescribeDayCount DescribePeriods DescribeLookup DescribeRounding DescribeLoanOutput DescribeShape ArgValues Flow Of Control Introduction Switch SwitchR SwitchT SwitchRT IfElse IfElseR IfElseT IfElseRT Comparisons Introduction CollarDate InBetween Collar Excel Information Introduction Ev
	Interpolation family
	Interpolation
	Description:
	Introduction: This family just deals with interpolation, where the number you are looking up may fall inbetween two values, and you want to in a sense get an average. Technically, of course, it is about putting the ranges you are looking up against on a graph (x=input, y=output) and returning the appropriate y value for the input x. This procedure is very distinct from curve-fitting, which you will see elsewhere in the library, because whereas a curve-fit fits a mathematical equation to some data where there is no guarantee that the equation goes through all the points, with interpolation the resultant curve must go through all the data points. In this sense Interpolation is perhaps more useful to financial analysts as it has less uncertainty involved, and who are not so concerned with the mathematical equation of the data, even if one actually exists. The are two kinds of function here, one that deals with plain numbers, and one that deals with a special kind of number that optionally uses extra inputs, dates. Within the two kinds of number and date functions, there are two ?flavours?. There is a short-form function that tries to keep the number of inputs to a minimum, and an ?all-singing? function that has the full range of inputs. The simple number interpolations are Interp (the short-form) and Interpolate (the all-singer). The date interpolation functions return a number given an InputDateValue, so this is where you might want to read an index or a price from a range governed by dates. Types of Interpolation Many of us think of interpolation as being just an exercise in linear or straight-line interpolation, or, when the input value is outside the data, extrapolation. In truth, very often when you think something cleverer than plain linear interpolation ought to work well, linear interpolations is actually the best thing to use. It has the benefit that people understand it and it is readily auditable and there is sometimes a resistance to doing something smarter. The default for our interpolation functions is always linear interpolation, but we do aim to cover the standard forms of mathematical interpolation in its wider sense, and have put in one method, exponential, that we ?borrowed? from techniques used in the petroleum industry, would you believe. The basic curve types available are cosine and cubic. Cosine is very good for producing a flowing, continuous curve, as is cubic, and they do not require any other inputs other than you specify the correct InterpType. Hermite is similar to Cubic, but you can optionally specify two extra variables that can further determine its shape, Tension and Bias. Exponential interpolation as implemented here has been specially developed by the Business Functions programmers, although the idea has been borrowed from the logic used in oil reservoirs where there is a constant rate of production decline. This logic has a particular applicability and theoretical relationship with any circumstance where there is a constant and continuous rate of decline or indeed growth, so inflation and continuous interest also fit this model. You only need to set InterpType (to 4) to model exponential interpolation, but you can also set a ?hyperbolic? exponent in the Tension variable, which in the special case of 1 becomes harmonic (growth or decline). Note that what exponential interpolation can?t do is guarantee a smooth curve, and if your data is more than 2 points and is not exponential in the underlying sense, there will be sharp changes of gradient (discontinuities), at the data points themselves.
	Functions in the Interpolation family (5) Interp Interpolate Interpolate Do a lookup that interpolates between values InterpDate Interpolate for Date inputs. InterpolateDate Do a lookup that interpolates between date values Intersection Find the intersection of 2 lines

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