How to replace element matrix with the other matrix?

What if I have a matrix A (4x4) with a size of (1x64 cell), and the matrix B (2x2) with size of (1x64 cell)? And I want to replace all of the matrix A.

[Amit]

what do you mean matrix A (4x4) with a size of (1x64 cell) and the same goes for B (2x2) with size of 1x64 cell?

[Image Analyst]

I don't understand. Are A and B cell arrays, or regular numerical arrays (int32 or double)? Is A a 1x64 cell array and in every one of those cells is a 4x4 array of doubles? Your explanation is not clear.

[Andi Tarigan]

I mean matrix A with size 4x4, but it have 64 pieces or block. And the matrix B with size 2x2, and it have 64 pieces or block, both have cell arrays. So I want to replace the middle of matrix A(size 2x2) with the matrix B.

[Bjorn Gustavsson]

Wouldnt this do it:

A(2:3,2:3) = B;

[Andi Tarigan]

How if I have 64 blocks of matrix A and matrix B with type cell arrays? But every blocks of matrix have type 4x4 double for matrix A and 2x2 double for matrix B. Please help me..

[Bjorn Gustavsson]

OK, this doesn't really work if you cant communicate clearly what A and B are. Instead of describing in words, paste the output of

whos A B

and in case A and B are a cell arrays also

size(A{1})
size(B{1})

[Andi Tarigan]

Do you mean like this?

>> A = Mmid1_blue_new;
>> whos A
  Name      Size            Bytes  Class    Attributes

    A         1x64             9216  cell               

>> B = blok_blue_dwt_dct_HL13;
>> whos B
  Name      Size            Bytes  Class    Attributes

    B         1x64            15360  cell

Answer 1

[Image Analyst]

OK, so both A and B are 1 by 64 cell arrays. And you say "And I want to replace all of the matrix A." Presumably replace A with B. So you do this:

A = B;

[Andi Tarigan]

But the size different, matrix A is 4x4 and matrix B 2x2. I just want to replace the middle matrix A(size 2x2) with matrix B.

[Image Analyst]

A is NOT 4 by 4. It is 1 by 64. You don't understand the concept of cell arrays. I really really suggest you read the FAQ on it: http://matlab.wikia.com/wiki/FAQ#What_is_a_cell_array.3F

Plus, you and I must have different definitions of "all". To me, your "all" means a subset (2x2 out of 4x4).

Answer 2

[Bjorn Gustavsson]

OK, then I suggest that (unless you definitely need the cell-array A as a cell-array) you first change A and B to 3-D matrices and put in B in A:

A = cat(3,A{:});
B = cat(3,B{:});
A(2:3,2:3,:) = B;

HTH.

[Andi Tarigan]

But I get error when I type:

>> B = cat(3,B{:});
Cell contents reference from a non-cell array object.

and

>> A(2:3,2:3,:) = B;
Subscripted assignment dimension mismatch.

[Bjorn Gustavsson]

Well, are you sure that B is a cell array at the time you call cat and you have the same sized (2 x 2) arrays in all cells of B?

The solution I suggested works in matlab 2013a...

Answer 3

[Jos (10584)]

I suggest that you give a smaller example of A and B and the required output.

[Andi Tarigan]

A =

   36.2700   10.5400
   38.2800   59.8200

B =

   -9.7800  -31.4500   79.9600   -2.6000
  -39.8500   35.8600   10.0700   -6.4300
  -91.7800   37.8300   59.3400  -35.3200
   15.2500  -29.0500   52.4800  -16.6700

B_output =

   -9.7800  -31.4500   79.9600   -2.6000
  -39.8500   36.2700   10.5400   -6.4300
  -91.7800   38.2800   59.8200  -35.3200
   15.2500  -29.0500   52.4800  -16.6700

But, I have 64 pieces both of that matrix.

[Jos (10584)]

So you want the central portion of B to be replaced with A.

What do you mean with "I have 64 pieces of both that matrix"?

[Bjorn Gustavsson]

Well that's completely opposite of your initial description of the sizes...

B(2:3,2:3) = A;

Would be what you'd do for that. For the case that B is 3-D you'd modify it to:

B(2:3,2:3,:) = A;

Answer 4

[Walter Roberson]

newA = cellfun(@(a,b) subsasgn(a, struct('type', '()', 'subs', {2:3, 2:3}), b), A, B, 'Uniform', 0);

I think.

[Andi Tarigan]

But I get error when type it:

>> newA = cellfun(@(a,b) subsasgn(a, struct('type', '()', 'subs', {2:3, 2:3}), b), A, B, 'Uniform', 0);
Error using cellfun
Input #2 expected to be a cell array, was double instead.

[Walter Roberson]

newA = cellfun(@(a) subsasgn(a, struct('type', '()', 'subs', {2:3, 2:3}), B), A, 'Uniform', 0);

Answer 5

[Jos (10584)]

To replace the central portion of B with A try this

% example data
A =  2 * ones(2,2)
B = -3 * ones(6,8)

% engine
szA = size(A) 
szB = size(B) 
tf = false(szB)
tf(1:szA(1),1:szA(2)) = true
tf = circshift(tf,(szB-szA)/2)

B_output = B 
B_output(tf) = A

Answer 6

[Jos (10584)]

Even simpler:

% example data
A =  99 * ones(2,2)
B = -1 * ones(6,8)
% engine
szA = size(A) 
i0 = (size(B)-szA)/2
B_output = B ;
B_output(i0(1)+1:i0(1)+szA(1), i0(2)+1:i0(2)+szA(2)) = A