is it possible to get index of reshaped matrix
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i have a matrix A of size 1*120 and reshaped it to matrix B of size 10*12..... is it possible to get the index values of where the value of A has gone to B in a matrix C of size 1*120....
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Jos (10584)
le 26 Fév 2014
A short story of LINEAR vs. SUB indexing:
A = [22 33 44 55 66 77]
B = reshape(A,2,[])
numel(A),numel(B) % the same number of elements
size(A), size(B) % but with different sizes
% However, reshaping does not change the intrinsic order of the elements inside an array.
% This intrinsic order is used by linear indexing:
LinIdx = 3 % any value between 1 and numel(A)
A(LinIdx), B(LinIdx)
% Linear indices correspond to different rows and columns for A and B,
% due to the different shapes between A and B:
LIDX = 1:numel(A) % all linear indices
[rowA, colA] = ind2sub(size(A), LIDX)
[rowB, colB] = ind2sub(size(B), LIDX)
rowB is what you call C
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Mischa Kim
le 26 Fév 2014
Modifié(e) : Mischa Kim
le 26 Fév 2014
This would do
An = 1:length(A);
nr = 10;
C(:,1) = floor((An-1)/nr) + 1;
C(:,2) = An' - nr*(C(:,1)-1);
where the first and second cols of C are the column and row indices.
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Sagar Damle
le 27 Fév 2014
C and C1,both are one and the same thing.
A = [22 33 44 55 66 77]
B = reshape(A,2,[])
temp = 1:size(B,1)
C = repmat(temp,1,size(B,2))
C1 = kron( ones(1,size(B,2)) , temp )
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