How to define a for loop for given FINDPEAKS problem ?

Question

Parvesh Deepan 2024-2-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2086253-how-to-define-a-for-loop-for-given-findpeaks-problem

评论： Dyuman Joshi 2024-2-29

采纳的回答： Dyuman Joshi

[A1,L] = findpeaks(A(:,1));

A1(:,2) = A(L,2);

[A2,L1] = findpeaks(A1(:,1));

A2(:,2) = A1(L1,2);

[A3,L2] = findpeaks(A2(:,1));

A3(:,2) = A2(L2,2);

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Dyuman Joshi 2024-2-24

编辑：Dyuman Joshi 2024-2-24

What exactly are you trying to do here?

Parvesh Deepan 2024-2-24

Bhuj78VDC.m

Actually the matrix A comprises of two columns. 1st column contains acceleration (dependent variable) and the 2nd column is associated time-period (Variable).

The whole code isattached herewith.

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Answer 1

Dyuman Joshi 2024-2-24

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2086253-how-to-define-a-for-loop-for-given-findpeaks-problem#answer_1415598

在 MATLAB Online 中打开

Try this -

n=3;
B = [num2cell(A,1); cell(n,2)]
for k=2:n
    [B{k,1}, L] = findpeaks(B{k-1,1});
    B{k,2} = B{k-1,2}(L);
end

Here 1st row of B corresponds to A, 2nd to A1, 3rd to A2 and 4th to A3.

Use indexing to access the data.

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Dyuman Joshi 2024-2-25

在 MATLAB Online 中打开

Chamoli1991VDC.m

Please specify what you are trying to do, and what needs to be optimized?

On a cursory glance, I can say that you can read the 3 data files and do the subplots in a for loop.

type Chamoli1991VDC.m
%%%%%%%%%%%%%%%%%%%%%%% Ground Motion Selection %%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%% Chamoli 1991 Earthquake - Acceleration (m/s/s);  %%%%%%%%%%%%%%

clc;
clear all;
close all;

%% Input:
h = 0.02;       % Time Step-Size
N = 1808;       % Number of Points
n = 4;           % Iteration needed to obtain Smooth Response Spectra
d1 = transpose(readmatrix('india.199110192123.abhat.dat','NumHeaderLines',6));□
d2 = transpose(readmatrix('india.199110192123.autta.dat','NumHeaderLines',6));□
d3 = transpose(readmatrix('india.199110192123.aghan.dat','NumHeaderLines',6));□

%% Output:□□
D1 = rmmissing(d1(:));
D2 = rmmissing(d2(:));□
D3 = rmmissing(d3(:));□
a1(:,1) = D1(1:N);□
a2(:,1) = D2(1:N);
a3(:,1) = D3(1:N);□□□□□
z1 = h*numel(a1);
z2 = h*numel(a2);
z3 = h*numel(a3);
t1 = transpose(h:h:z1);
t2 = transpose(h:h:z2);
t3 = transpose(h:h:z3);
a1(:,2) = t1(:);
a2(:,2) = t2(:);
a3(:,2) = t3(:);
A1 = [abs(a1)];
B1 = [num2cell(A1,1); cell(n,2)];
A2 = [abs(a2)];
B2 = [num2cell(A2,1); cell(n,2)];
A3 = [abs(a3)];
B3 = [num2cell(A3,1); cell(n,2)];
for k=2:n
    [B1{k,1}, L1] = findpeaks(B1{k-1,1});
    B1{k,2} = B1{k-1,2}(L1);
    [B2{k,1}, L2] = findpeaks(B2{k-1,1});
    B2{k,2} = B2{k-1,2}(L2);
    [B3{k,1}, L3] = findpeaks(B3{k-1,1});
    B3{k,2} = B3{k-1,2}(L3);
end
figure(1)
subplot(3,1,1)
plot(t1,a1(:,1),'r','LineWidth',1.25);
grid on;
xlabel('Time(in Seconds)');
ylabel('Acceleration (m/s/s)')
title('Acceleration Ground Motion - Chamoli Earthquake 1991:D1');

subplot(3,1,2)
plot(t2,a2(:,1),'b','LineWidth',1.25);
grid on;
xlabel('Time(in Seconds)');
ylabel('Acceleration (m/s/s)')
title('Acceleration Ground Motion - Chamoli Earthquake 1991:D2');

subplot(3,1,3)
plot(t3,a3(:,1),'k','LineWidth',1.25);
grid on;
xlabel('Time(in Seconds)');
ylabel('Acceleration (m/s/s)')
title('Acceleration Ground Motion - Chamoli Earthquake 1991:D3');


figure(2)
subplot(3,4,1)
plot(B1{1,2},smoothdata(B1{1,1}),'r','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,2)
plot(B1{2,2},smoothdata(B1{2,1}),'r','LineWidth',1.5);
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')
title('Spectral Acceleration Response Spectra - Chamoli Earthquake 1991:D1')

subplot(3,4,3)
plot(B1{3,2},smoothdata(B1{3,1}),'r','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,4)
plot(B1{4,2},smoothdata(B1{4,1}),'r','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,5)
plot(B2{1,2},smoothdata(B2{1,1}),'b','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,6)
plot(B2{2,2},smoothdata(B2{2,1}),'b','LineWidth',1.5);
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')
title('Spectral Acceleration Response Spectra - Chamoli Earthquake 1991:D2')

subplot(3,4,7)
plot(B2{3,2},smoothdata(B2{3,1}),'b','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,8)
plot(B2{4,2},smoothdata(B2{4,1}),'b','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,9)
plot(B3{1,2},smoothdata(B3{1,1}),'k','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,10)
plot(B3{2,2},smoothdata(B3{2,1}),'k','LineWidth',1.5);
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')
title('Spectral Acceleration Response Spectra - Chamoli Earthquake 1991:D3')

subplot(3,4,11)
plot(B3{3,2},smoothdata(B3{3,1}),'k','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

subplot(3,4,12)
plot(B3{4,2},smoothdata(B3{4,1}),'k','LineWidth',1.5);
grid on;
xlabel('Time(in Seconds)');
ylabel('Spectral Acceleration (m/s/s)')

Dyuman Joshi 2024-2-27

在 MATLAB Online 中打开

Dynamically naming variables is not a good coding practice.

Use dir to get the files in a given folder and read them in a loop -

%%%%%%%%%%% Chamoli 1991 Earthquake - Acceleration (m/s/s);  %%%%%%%%%%%%%%
%% Input:
h = 0.02;       % Time Step-Size
N = 1808;       % Number of Points
n = 4;           % Iteration needed to obtain Smooth Response Spectra
data = dir('india.199110192123.*.dat');
num = numel(d);
f1 = figure(1);
f2 = figure(2);
%text for labels
xstr = 'Time(in Seconds)';
ystr = 'Acceleration (m/s/s)';
for idx=1:num
    d = transpose(readmatrix(data(idx).name,'NumHeaderLines',6));
    %% Output:
    D = rmmissing(d(:));
    a(:,1) = D(1:N);
    t = h*transpose(1:numel(a));
    a(:,2) = t;
    A = abs(a);
    B = [num2cell(A,1); cell(n,2)];
    for k=2:n
        [B{k,1}, L] = findpeaks(B{k-1,1});
        B{k,2} = B{k-1,2}(L);
    end
    subplot(f1,3,1,idx)
    plot(t,a(:,1),'k','LineWidth',1.25);
    grid on;
    xlabel(xstr);
    ylabel(ystr);
    tstr = "Acceleration Ground Motion - Chamoli Earthquake 1991:D" + idx;
    title(tstr);
    for ij=1:4
        subplot(f2,3,4,ij+4*(idx-1))
        plot(B{ij,2},smoothdata(B{ij,1}),'r','LineWidth',1.5);
        grid on;
        xlabel(xstr);
        ylabel(ystr);
        if ij==2
            title(tstr)
        end
    end
end

Parvesh Deepan 2024-2-28

Chamoli Earthquake 1991.zip

it is giving error, "Unrecognized function or variable 'd'.

Error in Chamoli1991VDC02 (line 6)

num = numel(d);"

Let me share you the .dat file so that you can recheck from your end. By the way, thanks a lot man!!

Dyuman Joshi 2024-2-29

在 MATLAB Online 中打开

Ah, that's a typo. My bad.

To correct it, replace

num = numel(d);

with

num = numel(data);

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How to define a for loop for given FINDPEAKS problem ?

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