How to get the integral (function) from a vector?

Dear all,

I have a vector than can be plotted and I would like to compute its integral. I don't mean the total area below, but how it evolves over the domain of integration. Basically, its "indefinite" integral. Is this possible? maybe via interpolation?

Thank you

Answer 1

[Star Strider]

I would use the cumtrapz function to integrate it. The last value is the value of the entire integral.

[Image Analyst]

Or perhaps cumsum() depending on your philosophy of what integration means to you, or depending on the physics of the real world situation.

Answer 2

[Roger Stafford]

I wrote a function for the File Exchange which uses third order integration methods for discrete sets of points to obtain a cumulative integral, and is therefore usually more accurate than trapz or cumtrapz. It is located at:

http://www.mathworks.com/matlabcentral/fileexchange/19152-cumulative-cubic-integration .

[carlos g]

Hi Roger,

It worked just perfectly, thanks a lot!