How to integrate dataset over a certain domain ?

clear all
close all
clc
load data.txt
S_v = data(:,2);
T = data (:,1);
I_H = trapz(S_v); %Spectral_Intensity 

Here it integrates over the whole domain. But how can I integrate within the specified range ?

Answer 1

[Star Strider]

Perhaps:

load data.txt
S_v = data(:,2);
T = data (:,1);
Trange = (T >= 0.1) & (T <= 2.5);
I_H = trapz(T(Trange), S_v(Trange)); %Spectral_Intensity 

will do what you want. (Not able to test it without ‘data.txt’.)

Do not use clear or clc. It is simply inefficient.

[Sumit Saha]

@Star Strider Thank you so much. I just want to ask that for such integration using trapz command is completely okay? Because I'm calculating all these things for earthquake engineering.

[Star Strider]

As always, my pleasure!

With vectors or arrays, the trapz funciton is the only option. The other integration functions require function handle arguments, and integrate the functions themselves between specific limits.