MATLAB: Converting the 3D Matrix to 2D Matrix

MATLABreshapeStatistics and Machine Learning Toolbox

I have a matrix outputs from my function in the following form;
zeros(3,5,5)
Basically, its a result of pairwise comparison of a matrix
(5 x 5)
for
3
different modalities (types).
I wish to convert this matrix with each pairwise comparison matrix separately with respect to different modalities.i.e I wish to have the result as below;
1     2    3
i1    j1   k1
i2    j2   k2
i3    .    .
i4    .    .
i5    .    .
i6    .    .
.     .    .
.     .    .
.     .    .
.     .    .
i25   j25  k25
I checked the example using Reshape and could not get much from it. Can anyone please help me through? Thanks

Best Answer

The general reordering of elements can be done by:

y = reshape(permute(reshape(x, Size1), Order2), Size3)

In your case (perhaps - still not sure what "i1, j1, k1 etc" means):

x = zeros(3,5,5);
x(:) = 1:3*5*5;   % Some test data
y = reshape(permute(reshape(x, 3, 25), [2, 1]), [25, 3])

If this is the wanted output, there is an abbreviation:

y = reshape(x, 3, 25).'

permute(Matrix, [2,1]) is the same as mtranspose() and the 2nd reshape is not required here. But it is worth to keep the general transformation in mind.

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