How can I rotate a part of a matrix

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DM
DM on 24 Sep 2020
Commented: Ameer Hamza on 24 Sep 2020
Hi there,
I have a 4D images (dimensions [156 192 26 42]). I would like to rotate only the last 20 volumes of my 4D matrix and keep the first as it is.
I tried the following:
rotated_matrix=original_matrix;
rotated_matrix = rot90(original_matrix(:,:,:,23:42));
The rotated_matrix has been rotated but it has dimensions [192 156 26 20]. Basically it contains the volumes that have been rotated.
How can I rotate only the volume in the last 20 places and keep the first 22 as they are?

Answers (1)

Ameer Hamza
Ameer Hamza on 24 Sep 2020
Try something like this
rotated_matrix = original_matrix(:,:,:,[1:20 42:-1:21]);
  6 Comments
DM
DM on 24 Sep 2020
I might have put my question wrong. I didn't want to reverse the order of the last 20 elements.
I wanted to replace the last 20 elements in the 4th dimension of the original matrix with the 20 elements of the rotated_matrix.
Origina matrix has dimensions [156 192 26 42] where the rotated matrix has dimensions [156 192 26 20].
What I wanted to do is to replace the last 20 elemets of the original matrix with the 20 elemets of the rotated matrix.
Ameer Hamza
Ameer Hamza on 24 Sep 2020
Ok. I get it know. Following will work for this case
original_matrix(:,:,:,end-19:end) = rotated_matrix

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