How to integrate dataset over a certain domain ?

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Sumit Saha 2021-4-22

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/810355-how-to-integrate-dataset-over-a-certain-domain

评论： Star Strider 2021-4-23

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 ?

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Answer 1

Star Strider 2021-4-22

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/810355-how-to-integrate-dataset-over-a-certain-domain#answer_682250

在 MATLAB Online 中打开

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.

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Sumit Saha 2021-4-23

@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 2021-4-23

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.

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