# QuantLib_SegmentIntegral man page

SegmentIntegral — Integral of a one-dimensional function.

## Synopsis

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

Inherits 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

Generated automatically by Doxygen for QuantLib from the source code.

## Referenced By

SegmentIntegral(3) is an alias of QuantLib_SegmentIntegral(3).