Clear Filters
Clear Filters

How to make a m*2 matrix into n number of 2x2 matrices

4 views (last 30 days)
Hey,
I have, A = 208x2 matrix. I wish to to spit this matrix into 104 2x2 matrices. I have tried using num2cell and mat2cell but have had no luck. Any help would be appreicated.
Thanks.

Accepted Answer

Stephen23
Stephen23 on 7 Sep 2022
A = rand(208,2);
C = mat2cell(A,2*ones(104,1),2)
C = 104×1 cell array
{2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double} {2×2 double}
  6 Comments
Dyl
Dyl on 8 Sep 2022
Hey I have another question I reshaped the 2x1x104 matrix into a 13x8 matrix where I only took one value for each val(:,:,1) , valu(:,:,2) etc..
13x8 = [-28,-64 ... ;-33,-74...]
I wanted the values to insert into the 13x8 matric column wise so 1-8 for row 1 then 1-8 for row 2 so on, but they inserted row wise. How can I make the matrix I am after? Thanks in advance.

Sign in to comment.

More Answers (2)

KSSV
KSSV on 7 Sep 2022
A = rand(208,2) ;
[r,c] = size(A);
nlay = 104 ;
out = permute(reshape(A',[c,r/nlay,nlay]),[2,1,3]);

Abderrahim. B
Abderrahim. B on 7 Sep 2022
Split A
A = randi(10, 208, 2) ; % a mtarix of size 208x2
size(A)
ans = 1×2
208 2
B = reshape(A, 2, 2, []) ;
Access 2x2 matrices
B1 = B(:,:,1)
B1 = 2×2
5 7 9 6
B2 = B(:,:,2)
B2 = 2×2
8 8 4 1
Hope this helps
  2 Comments
Stephen23
Stephen23 on 7 Sep 2022
Edited: Stephen23 on 7 Sep 2022
Note that this method does not keep the 2x2 matrices of the original matrix:
A = randi(10, 208, 2)
A = 208×2
3 1 9 7 9 3 4 9 8 7 5 5 4 4 9 1 8 10 10 8
B = reshape(A, 2,2,[]) % not the same matrices
B =
B(:,:,1) = 3 9 9 4 B(:,:,2) = 8 4 5 9 B(:,:,3) = 8 5 10 4 B(:,:,4) = 2 1 10 10 B(:,:,5) = 2 5 7 9 B(:,:,6) = 4 7 4 9 B(:,:,7) = 6 9 4 6 B(:,:,8) = 10 9 2 3 B(:,:,9) = 10 4 6 4 B(:,:,10) = 8 5 2 5 B(:,:,11) = 4 2 6 4 B(:,:,12) = 5 1 6 8 B(:,:,13) = 7 4 4 6 B(:,:,14) = 3 7 6 6 B(:,:,15) = 4 4 7 9 B(:,:,16) = 9 6 2 10 B(:,:,17) = 8 9 7 6 B(:,:,18) = 3 3 2 4 B(:,:,19) = 6 1 6 3 B(:,:,20) = 4 3 10 10 B(:,:,21) = 5 9 6 5 B(:,:,22) = 2 2 8 10 B(:,:,23) = 4 8 3 7 B(:,:,24) = 9 7 2 3 B(:,:,25) = 8 10 6 9 B(:,:,26) = 6 7 8 4 B(:,:,27) = 7 10 10 1 B(:,:,28) = 3 9 7 4 B(:,:,29) = 4 3 9 10 B(:,:,30) = 4 5 3 2 B(:,:,31) = 2 5 9 5 B(:,:,32) = 2 9 9 4 B(:,:,33) = 2 1 6 9 B(:,:,34) = 8 1 3 4 B(:,:,35) = 2 4 4 3 B(:,:,36) = 7 1 5 4 B(:,:,37) = 10 7 1 10 B(:,:,38) = 8 1 1 10 B(:,:,39) = 10 4 1 8 B(:,:,40) = 2 7 9 7 B(:,:,41) = 3 10 2 7 B(:,:,42) = 8 5 9 5 B(:,:,43) = 3 10 10 1 B(:,:,44) = 7 9 2 3 B(:,:,45) = 2 10 9 10 B(:,:,46) = 8 1 9 6 B(:,:,47) = 5 8 7 9 B(:,:,48) = 2 2 3 2 B(:,:,49) = 3 2 3 5 B(:,:,50) = 4 2 9 3 B(:,:,51) = 7 10 10 3 B(:,:,52) = 9 5 3 3 B(:,:,53) = 1 3 7 9 B(:,:,54) = 7 4 5 1 B(:,:,55) = 10 2 8 10 B(:,:,56) = 7 8 8 4 B(:,:,57) = 3 3 6 1 B(:,:,58) = 9 2 5 6 B(:,:,59) = 10 9 6 3 B(:,:,60) = 1 9 5 4 B(:,:,61) = 5 9 4 3 B(:,:,62) = 7 9 8 5 B(:,:,63) = 3 7 3 10 B(:,:,64) = 8 10 10 8 B(:,:,65) = 6 10 9 4 B(:,:,66) = 8 2 7 3 B(:,:,67) = 3 6 5 3 B(:,:,68) = 7 5 5 6 B(:,:,69) = 3 6 6 10 B(:,:,70) = 4 4 6 1 B(:,:,71) = 2 7 6 8 B(:,:,72) = 1 6 1 5 B(:,:,73) = 7 1 10 1 B(:,:,74) = 1 3 4 6 B(:,:,75) = 1 4 5 9 B(:,:,76) = 10 10 9 1 B(:,:,77) = 10 2 4 4 B(:,:,78) = 4 8 8 3 B(:,:,79) = 10 1 10 8 B(:,:,80) = 6 5 7 9 B(:,:,81) = 10 9 8 5 B(:,:,82) = 5 5 5 8 B(:,:,83) = 1 8 5 1 B(:,:,84) = 10 4 4 8 B(:,:,85) = 8 7 6 4 B(:,:,86) = 4 10 4 2 B(:,:,87) = 9 6 3 2 B(:,:,88) = 9 7 9 7 B(:,:,89) = 10 8 10 7 B(:,:,90) = 1 3 9 4 B(:,:,91) = 7 4 1 8 B(:,:,92) = 10 9 5 9 B(:,:,93) = 2 4 6 8 B(:,:,94) = 6 3 7 10 B(:,:,95) = 10 9 10 2 B(:,:,96) = 10 5 3 2 B(:,:,97) = 10 4 9 4 B(:,:,98) = 10 5 9 8 B(:,:,99) = 5 7 6 7 B(:,:,100) = 7 10 1 9 B(:,:,101) = 1 2 7 9 B(:,:,102) = 8 3 5 6 B(:,:,103) = 10 10 4 8 B(:,:,104) = 6 10 3 4
To keep the original matrices requires taing into account the order of elements stored in memory:
B = permute(reshape(A.',2,2,[]),[2,1,3])
B =
B(:,:,1) = 3 1 9 7 B(:,:,2) = 9 3 4 9 B(:,:,3) = 8 7 5 5 B(:,:,4) = 4 4 9 1 B(:,:,5) = 8 10 10 8 B(:,:,6) = 5 2 4 10 B(:,:,7) = 2 7 10 8 B(:,:,8) = 1 8 10 4 B(:,:,9) = 2 3 7 6 B(:,:,10) = 5 3 9 1 B(:,:,11) = 4 9 4 5 B(:,:,12) = 7 2 9 6 B(:,:,13) = 6 10 4 6 B(:,:,14) = 9 9 6 3 B(:,:,15) = 10 1 2 5 B(:,:,16) = 9 9 3 4 B(:,:,17) = 10 5 6 4 B(:,:,18) = 4 9 4 3 B(:,:,19) = 8 7 2 8 B(:,:,20) = 5 9 5 5 B(:,:,21) = 4 3 6 3 B(:,:,22) = 2 7 4 10 B(:,:,23) = 5 8 6 10 B(:,:,24) = 1 10 8 8 B(:,:,25) = 7 6 4 9 B(:,:,26) = 4 10 6 4 B(:,:,27) = 3 8 6 7 B(:,:,28) = 7 2 6 3 B(:,:,29) = 4 3 7 5 B(:,:,30) = 4 6 9 3 B(:,:,31) = 9 7 2 5 B(:,:,32) = 6 5 10 6 B(:,:,33) = 8 3 7 6 B(:,:,34) = 9 6 6 10 B(:,:,35) = 3 4 2 6 B(:,:,36) = 3 4 4 1 B(:,:,37) = 6 2 6 6 B(:,:,38) = 1 7 3 8 B(:,:,39) = 4 1 10 1 B(:,:,40) = 3 6 10 5 B(:,:,41) = 5 7 6 10 B(:,:,42) = 9 1 5 1 B(:,:,43) = 2 1 8 4 B(:,:,44) = 2 3 10 6 B(:,:,45) = 4 1 3 5 B(:,:,46) = 8 4 7 9 B(:,:,47) = 9 10 2 9 B(:,:,48) = 7 10 3 1 B(:,:,49) = 8 10 6 4 B(:,:,50) = 10 2 9 4 B(:,:,51) = 6 4 8 8 B(:,:,52) = 7 8 4 3 B(:,:,53) = 7 10 10 10 B(:,:,54) = 10 1 1 8 B(:,:,55) = 3 6 7 7 B(:,:,56) = 9 5 4 9 B(:,:,57) = 4 10 9 8 B(:,:,58) = 3 9 10 5 B(:,:,59) = 4 5 3 5 B(:,:,60) = 5 5 2 8 B(:,:,61) = 2 1 9 5 B(:,:,62) = 5 8 5 1 B(:,:,63) = 2 10 9 4 B(:,:,64) = 9 4 4 8 B(:,:,65) = 2 8 6 6 B(:,:,66) = 1 7 9 4 B(:,:,67) = 8 4 3 4 B(:,:,68) = 1 10 4 2 B(:,:,69) = 2 9 4 3 B(:,:,70) = 4 6 3 2 B(:,:,71) = 7 9 5 9 B(:,:,72) = 1 7 4 7 B(:,:,73) = 10 10 1 10 B(:,:,74) = 7 8 10 7 B(:,:,75) = 8 1 1 9 B(:,:,76) = 1 3 10 4 B(:,:,77) = 10 7 1 1 B(:,:,78) = 4 4 8 8 B(:,:,79) = 2 10 9 5 B(:,:,80) = 7 9 7 9 B(:,:,81) = 3 2 2 6 B(:,:,82) = 10 4 7 8 B(:,:,83) = 8 6 9 7 B(:,:,84) = 5 3 5 10 B(:,:,85) = 3 10 10 10 B(:,:,86) = 10 9 1 2 B(:,:,87) = 7 10 2 3 B(:,:,88) = 9 5 3 2 B(:,:,89) = 2 10 9 9 B(:,:,90) = 10 4 10 4 B(:,:,91) = 8 10 9 9 B(:,:,92) = 1 5 6 8 B(:,:,93) = 5 5 7 6 B(:,:,94) = 8 7 9 7 B(:,:,95) = 2 7 3 1 B(:,:,96) = 2 10 2 9 B(:,:,97) = 3 1 3 7 B(:,:,98) = 2 2 5 9 B(:,:,99) = 4 8 9 5 B(:,:,100) = 2 3 3 6 B(:,:,101) = 7 10 10 4 B(:,:,102) = 10 10 3 8 B(:,:,103) = 9 6 3 3 B(:,:,104) = 5 10 3 4
Abderrahim. B
Abderrahim. B on 7 Sep 2022
Thanks @Stephen23. But he does not mention that the order must be te same as in the original matrix!

Sign in to comment.

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Community Treasure Hunt

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

Start Hunting!