I have 2 matrices with size (4,4) and (4,5) respectively. I want the element (2,1) in the second matrix to try all values in the first column in the first matrix and at each value, produce new matrix

I have 2 matrices with size (4,4) and (4,5) respectively. I want the element located at (2,1) in the second matrix to take all the values in the first column in the first matrix. How can I do this?

[Guillaume]

There are four elements in the each column of the first matrix.

There is one element at position (2,1) of any matrix.

How are you expecting to fit four elements into one?

Please provide a simple example of the inputs and corresponding desired output.

[Mahmoud Ahmed]

I want the element (2,1) in the second matrix to try all values in the first column in the first matrix and at each value, produce new matrix.

[KSSV]

It is confusing...an example would help.

[Mahmoud Ahmed]

A = [1:4 ; 5:8 ; 9:12 ; 13:16] B = zeros(4,5) B(2,1) = 0 now. I want B(2,1) to try all the values from the 1st column in A matrix B(2,1) = A(:,1) B(2,1) equals at the 1st time 1 at 2nd time 4 at 3rd time 9 at 4th time 13 and at each time I want to see the new B matrix

Answer 1

[KSSV]

A = [1:4 ; 5:8 ; 9:12 ; 13:16] ;
B = zeros(4,5) ;
for i = 1:4
    B(:,i) = A(:,i)
end

[Mahmoud Ahmed]

I want B(2,1) only to take the values from the first column in A, not all the other elements

[KSSV]

A = [1:4 ; 5:8 ; 9:12 ; 13:16] ;
B = zeros(4,5) ;
B(:,1) = A(:,1) ;

simple

[Mahmoud Ahmed]

with this code, the output is B =

     1     0     0     0     0
     5     0     0     0     0
     9     0     0     0     0
    13     0     0     0     0
and I want B(2,1) only to be assigned with each value from the 1st column of A at different times

[KSSV]

A = [1:4 ; 5:8 ; 9:12 ; 13:16] ;
B = zeros(4,5) ;
for i = 1:4
    B(i,1) = A(i,1)
end

Answer 2

[Guillaume]

Probably the easiest is to replicate your B in the 3rd dimension and copy the column of A along that dimension.

A = [1:4 ; 5:8 ; 9:12 ; 13:16] 
B = rand(4, 5);

newB = repmat(B, [1, 1, size(A, 1)]);  %replicate B in the 3rd dimensions as many times as there are rows in A 
newB(2, 1, :) = A(:, 1);  %and copy 1st column of A, overwrite whatever was in B(2, 1)

You can then iterate over the pages (3rd dimension) of that newB to do whatever it is you want to do.

for page = 1 :size(newB, 3)
   %do something with B(:, :, page)
end