Matrix inserted within a matrix element

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Andy McCann
Andy McCann on 7 Apr 2012
Hi, I'm looking for help replacing an element of a matrix with a new matrix. I have a large matrix where i wish to replace every element with a 1x3 row vector, is this possible? If not you may be able to suggest a different approach. Essentially i wish for every element in a matrix to contain the values for a spherical polar vector. So a value for r, theta and phi. Is there a better way to do this, short of making the original vector 3 times as long, as this causes problems in addressing the entries. Thanks Andy

Answers (1)

Image Analyst
Image Analyst on 7 Apr 2012
So just add a third dimension
m=rand(5,5) % Create sample data.
% Now we want three numbers at each location insted of 1.
% So add a dimension with 2 more planes
blankPlane = zeros(size(m))
m = cat(3, m, blankPlane, blankPlane)
% Assign a 1x3 row vector to the 1,1 location
rowVector = [1 2 3] % Create row vector.
m(1,1,:) = rowVector;
% Let's do it again at the 3,3 location.
rowVector = [10 20 30] % Create row vector.
m(3,3,:) = rowVector
You might have t in plane 1 m(:,:,1), theta might be in plane 2 m(:,:,2), and you might have phi in plane 3 m(:,:,3), or however you want to do it.

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