2D Array Manipulation / Script

2012 9 6
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I am looking to write a simple MATLAB script that will take any 2D array and double its size by duplicating every entry in the horizontal, vertical, and diagonal direction. The catch is I can not use for-loops. I have been thinking about using repmat(), but am unsure how this could translate to my problem.
For example, if I have a matrix A = [1 4 7 ; 8 9 3], then the result should be:
A=[
1 1 4 4 7 7
1 1 4 4 7 7
8 8 9 9 3 3
8 8 9 9 3 3
]
I hope I am articulating my thoughts well. Any help or tips would be greatly appreciated.

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Azzi Abdelmalek
Azzi Abdelmalek 2012-9-6
编辑：Azzi Abdelmalek 2012-9-6

0 个投票

%method1
res=cell2mat(arrayfun(@(x) repmat(x,2,2),A,'uni',false))
%or method 2
[n,m]=size(A)
B=zeros(n,2*m);
B(:,1:2:2*m)=A;B(:,2:2:2*m)=A
C=zeros(2*n,2*m);
C(1:2:2*n,:)=B;C(2:2:2*n,:)=B

更多回答（1 个）

Matt Fig
Matt Fig 2012-9-6

0 个投票

You can also use expand, which is written to be more general and memory efficient.
A = [1 4 7 ; 8 9 3],
expand(A,[2,2])
ans =
1 1 4 4 7 7
1 1 4 4 7 7
8 8 9 9 3 3
8 8 9 9 3 3

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