How can i fill a pre-allocated matrix 2D?

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Harry Smith
Harry Smith 2021-7-25
评论： Image Analyst 2021-7-25
Hello everyone!
i hope you can help me.
My code is:
[A, B]=size(storage);
nan_matrix=NaN(500,1000);
for ii=1:A
for k=1:B
[x,y]=corr(....)
end
end
%put x-values in the nan_matrix and save this matrix
How?
  6 个评论
显示 4更早的评论
Harry Smith
Harry Smith 2021-7-25
For example:
[rho, p_val]=corr(x,y, 'type', 'spearman');
the x_dimension is: 300x4
So I preallocated a matrix:
nan_matrix=NaN(500,1000);
in which to store the various rho, otherwise every time the loop restarts for the next column of x, the results will be overwritten.
I can't figure out how to store the results in the pre-allocated matrix before the cycle restarts.
I can do this with an empty vector:
example:
[A, B]=size(storage);
empty_vector=[];
for ii=1:A
for k=1:B
[x,y]=corr(....)
empty_vecto=[empty_vector; x]
end
end
but not with a nan matrix of a particular size
dpb
dpb 2021-7-25
[rho, p_val]=corr(x,y, 'type', 'spearman');
the x_dimension is: 300x4
So, what is y?
"If you input matrices X and Y, rho is a k1-by-k2 matrix, where k1 and k2 are the number of columns in X and Y, respectively. The entry rho(a,b) is the pairwise linear correlation coefficient between column a in X and column b in Y."
I still don't follow why you think you need other storage...

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回答（1 个）

Image Analyst
Image Analyst 2021-7-25
I'd use xcorr2().
  2 个评论
Image Analyst
Image Analyst 2021-7-25
It's a sliding window that gives you the correlation of one set of data with another. What were you thinking of doing when you had corr() inside the double nested for loop?

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