# QuantLib_InterestRate man page

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, **Compounding** comp, **Frequency** freq)

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** (**Compounding** comp, **Frequency** freq, **Time** t) const

equivalent interest rate for a compounding period t. **InterestRate equivalentRate** (const **DayCounter** &resultDC, **Compounding** comp, **Frequency** freq, **Date** d1, **Date** d2, const **Date** &refStart=**Date**(), const **Date** &refEnd=**Date**()) const

equivalent rate for a compounding period between two dates

### Static Public Member Functions

**implied rate calculations**

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

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

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

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**.

## 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, const DayCounter & resultDC, Compounding comp, Frequency freq, Time t) [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 DayCounter & resultDC, Compounding comp, Frequency freq, const Date & d1, const Date & d2, const Date & refStart = Date(), const Date & refEnd = Date()) [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 (Compounding comp, Frequency freq, Time t) 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 (const DayCounter & resultDC, Compounding comp, Frequency freq, Date d1, Date d2, const Date & refStart = Date(), const Date & refEnd = Date()) 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

## Author

Generated automatically by Doxygen for QuantLib from the source code.

## Referenced By

compoundFactor(3), equivalentRate(3), impliedRate(3) and InterestRate(3) are aliases of QuantLib_InterestRate(3).