How do I store result from a loop into matrix?
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I have 360 signals to be processed and I'm using STFT for my project. The result for one signal returns:
S = 33x147 double
How do I take only the first column from every 360 signals processed and store it in the same matrix? And how do I make a loop to make it do the same thing but advance to the next column up to the 147th column until I've 147 different matrices of result S?
Thank you in advance.
2 个评论
Ameer Hamza
2018-5-6
Does your result require 147 matrices at the end? Like this
Result{1} = [first columns of S for all 360 signals] = 33 x 360 matrix
Result{2} = [second columns of S for all 360 signals] = 33 x 360 matrix
....
Result{147} = [147th columns of S for all 360 signals] = 33 x 360 matrix
Syed Farez
2018-5-6
编辑：Syed Farez
2018-5-6
采纳的回答
The first column of S can be indexed S(:,1). The nth is S(:,n);
Instead of making 360 different matrices with different names, we're going to make a three-dimensional array, A, with 360 different pages.
clearvars
num_rows = 33;
num_signals = 360;
num_pages = 147;
A = zeros(num_results, num_signals, num_pages);
for jj = 1:num_signals
% replace the following line with your calculation of S
S = rand(num_results,num_pages);
A(:,jj,:) = reshape(S,num_results,1,num_pages);
end
Each page of A (the different columns from your values of S pasted together into a matrix) can be indexed as:
page_of_columns = A(:,:,n)
where 'n' is the column id you want (from 1 to 147 in your example)
7 个评论
Syed Farez
2018-5-6
num_rows is the 33 in the size(S) = [33 147] in your problem statement.
Edit: There were 3 values described in your problem statement. [33 147] was the size of each S. Those are num_rows and num_pages respectively. You also mentioned you had 360 such signals. That's num_signals.
I didn't hard code the numbers in case you wanted to change the number of signals, or the amount of data per S.
Syed Farez
2018-5-6
Wick
2018-5-6
You wouldn't put the 'load' command inside the 'for' loop. There's no need to load it 360 times (unless there are 360 different files to load...).
My 'rand' command was just something to make a 33x147 matrix to work with. You should replace that line with each value of S for each of the 360 signals one at a time.
Syed Farez
2018-5-6
clearvars
num_rows = 33;
num_signals = 360;
num_pages = 147;
num_results = 1;
A = zeros(num_results, num_signals, num_pages);
% load a .mat file
load ('Defect_Signals_with_Labels.mat');
for jj = 1:num_signals
x = Signals_Combined(:,jj);
.....
S = 20*log10(S + 1e-6);
A(:,jj,:) = reshape(S,num_results,1,num_pages);
end
The assumption is that 'S' is different each time based on whatever is above it inside the loop.
Syed Farez
2018-5-6
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