Path: news.mathworks.com!not-for-mail From: "Neal Lafferty" <nxl7930@rit.edu> Newsgroups: comp.soft-sys.matlab Subject: Re: numerical integration from data in cylindrical coordinates Date: Thu, 7 Oct 2010 13:16:03 +0000 (UTC) Organization: IBM Corp Lines: 11 Message-ID: <i8kh6j$o3$1@fred.mathworks.com> References: <i8icjm$l55$1@fred.mathworks.com> <i8il74$ro0$1@fred.mathworks.com> <i8imf2$k2o$1@fred.mathworks.com> Reply-To: "Neal Lafferty" <nxl7930@rit.edu> NNTP-Posting-Host: webapp-05-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: fred.mathworks.com 1286457363 771 172.30.248.35 (7 Oct 2010 13:16:03 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Thu, 7 Oct 2010 13:16:03 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 2544966 Xref: news.mathworks.com comp.soft-sys.matlab:676545 > I failed to read your subject title carefully. Apparently your array of points correspond to radius r and distance z cylindrical coordinates, and you are attempted to find the numerical triple integral of some quantity that is constant with respect to theta, and which would therefore require only an appropriate double integration. Is that correct? > > Roger Stafford Roger, Thanks for taking a look and responding to my post. You are correct, I would like to perform a double integral (numerically) on my data. The problem is that now, using cumtrapz, I have to integrate over the columns first, and then re-run to integrate the rows. I'd like to have the data where I can take the cumulative integral over 0 to 2pi, and from r=0 to some radius. To better illustrate, my data resembles http://en.wikipedia.org/wiki/File:Airy-pattern.svg when plotted with imagesc. I'd like to plot the cumulative volume under the curve with respect to radius, over 360 degrees. Graphically, it would resemble http://en.wikipedia.org/wiki/File:Airy_Pattern_Intensity_and_Encircled_Power.svg So in short I want to numrically integrate an array that has rows/columns (cartesian) data in cylindrical coordinates. Is that possible in MATLAB? Thanks for the responses! I hope I could clarify.