trivial matrix question: how to rearrange matrices in a given order

Hello everyone,

I know this could seems trivial and meybe here we are talking about the very matlab basics, but as I am dealing with really big data structures, I would like to receive some support.

I have the following matrix, as shown in 1:

I would like to reshape it to be as in 2, and back again to point 1.

Thanks in advance

Answer 1

[Matt J]

You can use blkColon in this FEX download,

https://www.mathworks.com/matlabcentral/fileexchange/115340-block-transposition-permutation-and-reshaping-of-arrays

>> X

X(:,:,1) =

1 10 19

2 11 20

3 12 21

X(:,:,2) =

4 13 22

5 14 23

6 15 24

X(:,:,3) =

7 16 25

8 17 26

9 18 27

>> Y=blkColon(X,[3,3])

Y =

1 10 19

2 11 20

3 12 21

4 13 22

5 14 23

6 15 24

7 16 25

8 17 26

9 18 27

[Enzo]

@Matt J thanks for your precious help. I am gonna accept your answer has it worked perfectly. Do you have any suggestion on how to reshape the Y matrix again into the X matrix shape?

[Matt J]

Yes, you can use blkReshape().

Answer 2

[chicken vector]

A = reshape(1:3^3,3^2,[])

A = 9×3

1 10 19 2 11 20 3 12 21 4 13 22 5 14 23 6 15 24 7 16 25 8 17 26 9 18 27

B = permute(reshape(A',[],3,3),[2,1,3])

B = 
B(:,:,1) =

     1    10    19
     2    11    20
     3    12    21


B(:,:,2) =

     4    13    22
     5    14    23
     6    15    24


B(:,:,3) =

     7    16    25
     8    17    26
     9    18    27

A = reshape(B,[],3)

A = 9×3

1 4 7 2 5 8 3 6 9 10 13 16 11 14 17 12 15 18 19 22 25 20 23 26 21 24 27