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REPLICATE

version 1.2 (1.76 KB) by

Create a larger array by expanding each element of an array into a subarray.

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REPLICATE is a companion to REPMAT, but instead of tiling a larger array with the input array, REPLICATE does the equivalent of calling REPMAT on each individual element and then tile the results together. It is faster than looping over each element. It supports 2D and 3D arrays.

Comments and Ratings (5)

Russell

I used replicate.m to generate some padding on a string cell array.

AA = {'blank'};
myLabels = {'fish','beer'};
myLabels = [ myLabels (replicate (AA,1,3)) ]
myLabels =
    'fish' 'beer' 'blank' 'blank' 'blank'

Mark Ruzon

This is a more elegant and faster solution for the 2D case. The next version of the file will have this solution. Unfortunately, KRON gives 2D results when Y is 3D, so a different approach is needed in the 3D case.
A = reshape(1:6,[1 3 2]);
S = [2 2 2];
A(kron(reshape(1:numel(A),size(A)),ones(S)))
replicate(A,S)

Jos (10584)

Jos (10584) (view profile)

Indexing with KRON is equally flexible:
% data
A = {12 {'yy' 'xxx'} ; 'aaa' rand(2)}
nr = 3 ;
nc = 5 ;
% engine
B = A(kron(reshape(1:numel(A),size(A)),ones([nr nc])))

Mark Ruzon

KRON works for floats and doubles but not integral types, structs, or cell arrays. KRON relies on multiplication, while REPLICATE uses only indexing, thus making it more flexible.

Jos (10584)

Jos (10584) (view profile)

Nice try, but KRON can handle the job perfectly, for instance, kron(A,ones([2, 3]))

Updates

1.2

Sped up 2D case using KRON. Thanks go to Jos.

1.1

Bug fix: renamed input parameter.

MATLAB Release
MATLAB 7.5 (R2007b)

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