# SegmentIntegral (3) - Linux Man Pages

## SegmentIntegral: Integral of a one-dimensional function.

## NAME

QuantLib::SegmentIntegral - Integral of a one-dimensional function.

## SYNOPSIS

#include <ql/math/integrals/segmentintegral.hpp>

Inherits QuantLib::Integrator.

### Public Member Functions

**SegmentIntegral** (Size intervals)

### Protected Member Functions

virtual Real **integrate** (const boost::function< Real(Real)> &f, Real a, Real b) const

## Detailed Description

Integral of a one-dimensional function.

Given a number $ N $ of intervals, the integral of a function $ f $ between $ a $ and $ b $ is calculated by means of the trapezoid formula [ int_{a}^{b} f mathrm{d}x = ac{1}{2} f(x_{0}) + f(x_{1}) + f(x_{2}) + ots + f(x_{N-1}) + ac{1}{2} f(x_{N}) ] where $ x_0 = a $, $ x_N = b $, and $ x_i = a+i Delta x $ with $ Delta x = (b-a)/N $.

**Tests**

- the correctness of the result is tested by checking it against known good values.

## Author

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