Given an element of a matrix, How to print all the arrays containing that element?

Given an element of a matrix, I need to print all the arrays containing that element. So basicaly for each element I need 4 arrays.

Suppose I have the matrix:

A = magic(4)

A =

16 2 3 13

5 11 10 8

9 7 6 12

4 14 15 1

If I give input

x = 7

I should get output as:

out1 = 0  9  6  12
out2 = 0  2  11  14
out3 = 0  5  15  0
out4 = 13 10  4  0

Any help will be appreciated. Thank You.

[dpb]

'Splain how you come up with out3 and out 4, in particular.

I can see 1 & 2 provided out2 is [0 2 11 14] instead of [0 1 2 14] but I fail to see the logic behind the others.

[sangeet sagar]

I am sorry I was not clear.

I will attach this pic to give you the idea.

[Jan]

Is this a homework? How is the order of the elements in the output defined? What is the wanted output for x=4?

[sangeet sagar]

No Jan, this is not a home work. I am trying image reconstruction using regression polynomial. If I find out how to do this, I would try it on a image matrix

[Jan]

And what is the wanted output for x=4? Is it wanted, that the mask is not symmetric?

Answer 1

[Stephen23]

This should get you started, adjust as required:

>> A = magic(4)
A =
   16    2    3   13
    5   11   10    8
    9    7    6   12
    4   14   15    1
>> N = 7;
>> Rv = {[+0,+0,+0,+0],[-3,-2,-1,+1],[-2,-1,+1,+2],[-2,-1,+1,+2]};
>> Cv = {[-2,-1,+1,+2],[+0,+0,+0,+0],[-2,-1,+1,+2],[+2,+1,-1,-2]};
>> B = zeros(size(A)+5);
>> B(4:end-2,4:end-2) = A;
>> [Rx,Cx] = find(B==N);
>> F = @(r,c)reshape(B(sub2ind(size(B),Rx+r,Cx+c)),1,[]);
>> Z = cellfun(F,Rv,Cv,'Uni',0);
>> Z{:}
ans =
    0    9    6   12
ans =
    0    2   11   14
ans =
    0    5   15    0
ans =
   13   10    4    0

You can access the data in the cell array using indexing:

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-cell-array.html

You could probably do something similar using blockproc:

https://www.mathworks.com/help/images/ref/blockproc.html