File Exchange

## A double integration of the tabulated data.

version 1.0.0.0 (524 Bytes) by
A double integration of the tabulated data.

Updated 12 Jan 2007

A double integration of the tabulated data. f(x,y) may be generated in terms of meshgrid. Double integral computes simply by approximation of the integral for f(x,y) via the trapezoidal method.
Firstly, an integration loop within inner integral over X is performed obtaining the function of area A(y). Secondly, outer loop integration is performed for A(y) over y limits
Example:
Q = dblquad(inline('y*sin(x)+x*cos(y)'), pi, 2*pi, 0, pi);
Q = -9.8696
[X,Y] = meshgrid(pi:pi/100:2*pi, 0:pi/100:pi );
Z=Y.*sin(X)+X.*cos(Y);
int_2D_tabulated(X,Y, Z )
ans = -9.8688

### Cite As

Robertas balevicius (2021). A double integration of the tabulated data. (https://www.mathworks.com/matlabcentral/fileexchange/13644-a-double-integration-of-the-tabulated-data), MATLAB Central File Exchange. Retrieved .

dave martin

function V = int_2D_tabulated(X, Y, Z )
V = trapz( Y(:,1), (trapz(X(1,:),Z, 2)) );

dave martin

Sorry, there is no need for the return statement. This is essentially a one liner with a name that is harder to remember than 'trapz' in the first place. This is cumbersome!

John D'Errico

But I can call trapz twice with no more effort. Why bother with a special function for something this trivial, since all it does is call trapz twice anyway?

##### MATLAB Release Compatibility
Created with R13
Compatible with any release
##### Platform Compatibility
Windows macOS Linux