How to do Numerical Integration of excel data using gauss quadrant?

4 views (last 30 days)
Hello all,
I am trying to do a numerical integration of a excel data using gauss quadrant method. I have a function Q = f(Y) which is Q = A*Y, Whre Y is the data from excel at different X positions. I have tried using gauss_quad function. But I am getting an error in it. How can i get the integral value at every location along with a curve of the integral data? Please kindly help me.
My code:
function [I]=Gauss_quad(fstr,a,b)
if nargin<1,
help Gauss.m;
v = xlsread('flow.xlsx','B:B');
r = 0.0685;
A = pi*r^2;
fstr='A*Y';
a=0.01; b=1.5;
end
f=vectorize(inline(fstr,0));
% Seven-point integration scheme so zeta_1 to zeta_7
zeta=[-0.9491079123; -0.7415311855; -0.4058451513; 0.0;
0.4058451513; 0.7415311855; 0.9491079123];
% Weighting coefficients
w=[0.1294849661; 0.2797053914; 0.3818300505; 0.4179591836;
0.3818300505; 0.2797053914; 0.1294849661];
% Index for the seven points
Index=1:7;
% Gauss Integration
I=(b-a)/2*sum(w(Index).*f((b-a).*(zeta(Index)+1)/2+a));
% Display the result
disp(' '); disp(strcat('The integral = ', num2str(I)));

Answers (0)

Categories

Find more on Numerical Integration and Differential Equations in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!