Filter löschen
Filter löschen

How to extract diagonal elements of multiple nxn square matrix and place them in single mat file or matrix?

8 Ansichten (letzte 30 Tage)
Hello,
I have 500 mat files with 10x10 double dimension. I want to extract the 10 diagonal elements from each matrix and place them in a single matrix which will be 500x10 (500 rows and 10 columns) each row consists of diagonal elements of one matrix. How can I make a single variable with all the diagonal elements?
Thanks
  6 Kommentare
Stephen23
Stephen23 am 28 Sep. 2018
@Varun Mandalapu: note that concatenating onto the output array is not very efficient. For a more efficient solution you should preallocate the output array and use indexing, as ytzhak goussha's answer shows.
Sunny
Sunny am 28 Sep. 2018
Thanks @Stephen. Yes, I used ytzhak answer for this issue and accepted his answer

Melden Sie sich an, um zu kommentieren.

Akzeptierte Antwort

ytzhak goussha
ytzhak goussha am 27 Sep. 2018
Hope this helps
step1:creat a nXnXm with random elements for the example:
%set dimensions of matrix
size_of_matrix=10;
number_of_matricides=500;
mat_input=randi(30,size_of_matrix,size_of_matrix,number_of_matricides);
step2: initialize an output matrix with nXm dimensions
mat_output=zeros(number_of_matricides,size_of_matrix);
step3: extract a diagonal from each matrix and place them in the output matrix
for i=1:number_of_matricides
mat_output(i,:)=diag(mat_input(:,:,i));
end
Alternatively, though not recommended, you can simply concatenate:
%initialize an empty matrix
mat_output=[];
for i=1:number_of_matricides
mat_output=[mat_output;diag(mat_input(:,:,i))'];
end
  5 Kommentare
Guillaume
Guillaume am 21 Okt. 2018
@yzthak,
Just reread your answer in more details, and I noticed something that made me chuckle:
You may want to read the definition of matricide. I believe you meant matrices
Sunny
Sunny am 21 Okt. 2018
Bearbeitet: Sunny am 21 Okt. 2018
Thanks for the comment, I figured out that I need to create a struct with all the variables and access it. I already created a question and the link is New_Question

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (0)

Kategorien

Mehr zu Operating on Diagonal Matrices finden Sie in Help Center und File Exchange

Produkte


Version

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by