# discountFactor (3) - Linux Manuals

## discountFactor: Concrete interest rate class.

## NAME

QuantLib::InterestRate - Concrete interest rate class.

## SYNOPSIS

#include <ql/interestrate.hpp>

### Public Member Functions

**constructors**

**InterestRate** ()

*Default constructor returning a null interest rate. *

**InterestRate** (**Rate** r, const **DayCounter** &dc=**Actual365Fixed**(), Compounding comp=Continuous, **Frequency** freq=Annual)

*Standard constructor. *

**conversions**

**operator Rate** () const

**inspectors**

**Rate** **rate** () const

const **DayCounter** & **dayCounter** () const

Compounding **compounding** () const

**Frequency** **frequency** () const

**discount/compound factor calculations**

**DiscountFactor** **discountFactor** (**Time** t) const

*discount factor implied by the rate compounded at time t. *

**DiscountFactor** **discountFactor** (const **Date** &d1, const **Date** &d2, const **Date** &refStart=**Date**(), const **Date** &refEnd=**Date**()) const

*discount factor implied by the rate compounded between two dates *

Real **compoundFactor** (**Time** t) const

*compound factor implied by the rate compounded at time t. *

Real **compoundFactor** (const **Date** &d1, const **Date** &d2, const **Date** &refStart=**Date**(), const **Date** &refEnd=**Date**()) const

*compound factor implied by the rate compounded between two dates *

**equivalent rate calculations**

**InterestRate** **equivalentRate** (**Time** t, Compounding comp, **Frequency** freq=Annual) const

*equivalent interest rate for a compounding period t. *

**InterestRate** **equivalentRate** (**Date** d1, **Date** d2, const **DayCounter** &resultDC, Compounding comp, **Frequency** freq=Annual) const

*equivalent rate for a compounding period between two dates *

### Static Public Member Functions

**implied rate calculations**

static **InterestRate** **impliedRate** (Real compound, **Time** t, const **DayCounter** &resultDC, Compounding comp, **Frequency** freq=Annual)

*implied interest rate for a given compound factor at a given time. *

static **InterestRate** **impliedRate** (Real compound, const **Date** &d1, const **Date** &d2, const **DayCounter** &resultDC, Compounding comp, **Frequency** freq=Annual)

*implied rate for a given compound factor between two dates. *

### Related Functions

(Note that these are not member functions.)std::ostream &

**operator<<**(std::ostream &, const

**InterestRate**&)

## Detailed Description

Concrete interest rate class.

This class encapsulate the interest rate compounding algebra. It manages day-counting conventions, compounding conventions, conversion between different conventions, discount/compound factor calculations, and implied/equivalent rate calculations.

**Tests**

- Converted rates are checked against known good results

**Examples: **

**CallableBonds.cpp**, and **FittedBondCurve.cpp**.

## Member Function Documentation

**DiscountFactor** discountFactor (**Time** t) const

discount factor implied by the rate compounded at time t.

**Warning**

- Time must be measured using InterestRate's own day counter.

### Real compoundFactor (**Time** t) const

compound factor implied by the rate compounded at time t.

returns the compound (a.k.a capitalization) factor implied by the rate compounded at time t.

**Warning**

- Time must be measured using InterestRate's own day counter.

### Real compoundFactor (const **Date** & d1, const **Date** & d2, const **Date** & refStart = **Date**(), const **Date** & refEnd = **Date**()) const

compound factor implied by the rate compounded between two dates

returns the compound (a.k.a capitalization) factor implied by the rate compounded between two dates.

### static **InterestRate** impliedRate (Real compound, **Time** t, const **DayCounter** & resultDC, Compounding comp, **Frequency** freq = Annual) [static]

implied interest rate for a given compound factor at a given time.

The resulting **InterestRate** has the day-counter provided as input.

**Warning**

- Time must be measured using the day-counter provided as input.

### static **InterestRate** impliedRate (Real compound, const **Date** & d1, const **Date** & d2, const **DayCounter** & resultDC, Compounding comp, **Frequency** freq = Annual) [static]

implied rate for a given compound factor between two dates.

The resulting rate is calculated taking the required day-counting rule into account.

**InterestRate** equivalentRate (**Time** t, Compounding comp, **Frequency** freq = Annual) const

equivalent interest rate for a compounding period t.

The resulting **InterestRate** shares the same implicit day-counting rule of the original **InterestRate** instance.

**Warning**

- Time must be measured using the InterestRate's own day counter.

**InterestRate** equivalentRate (**Date** d1, **Date** d2, const **DayCounter** & resultDC, Compounding comp, **Frequency** freq = Annual) const

equivalent rate for a compounding period between two dates

The resulting rate is calculated taking the required day-counting rule into account.

## Friends And Related Function Documentation

### std::ostream & operator<< (std::ostream &, const **InterestRate** &) [related]

## Author

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