Cell components perpendicular division

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MarshallSc 2021-7-17

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https://ww2.mathworks.cn/matlabcentral/answers/880783-cell-components-perpendicular-division

编辑： DGM 2021-7-17

If I have a 4*4 cell array that each contain a 10*10 matrix as below (for example, Aii=10*10 matrix):

A={Aii Aij Aik Ail;
     Aji Ajj Ajk Ajl;
     Aki Akj Akk Akl;
     Ali Alj Alk All};

How can I get a similiar cell array that denotes the division of perpendicular components such that I would get:

C={[Aii/Ajj] [Aij/Ajk] [Aik/Ajl] [Ail/Aji];
   [Aji/Akj] [Ajj/Akk] [Ajk/Akl] [Ajl/Aki];
   [Aki/Alj] [Akj/Alk] [Akk/All] [Akl/Ali];
   [Ali/ij] [Alj/Aik] [Alk/Ail] [All/Aii]};

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Answer 1

DGM 2021-7-17

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Something like:

A = num2cell(reshape(1:16,[4 4])) % example array
B = cellfun(@rdivide,A,circshift(A,[-1 -1])) % output

To describe the shifting, consider the example:

A = {'Aii' 'Aij' 'Aik' 'Ail';
	'Aji' 'Ajj' 'Ajk' 'Ajl';
	'Aki' 'Akj' 'Akk' 'Akl';
	'Ali' 'Alj' 'Alk' 'All'};
circshift(A,[-1 -1])
ans = 4×4 cell array
    {'Ajj'}    {'Ajk'}    {'Ajl'}    {'Aji'}
    {'Akj'}    {'Akk'}    {'Akl'}    {'Aki'}
    {'Alj'}    {'Alk'}    {'All'}    {'Ali'}
    {'Aij'}    {'Aik'}    {'Ail'}    {'Aii'}

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DGM 2021-7-17

编辑：DGM 2021-7-17

在 MATLAB Online 中打开

Yeah, you might need to set uniformoutput depending on what's in the array.

There isn't a difference between false or 0 when setting 'uniformoutput'. A lot of things are implicit in Matlab where possible. false is explicitly a logical scalar. 0 is a numeric scalar, but it's treated implicitly as a logical false when used in a logical context (and all nonzero numeric values are treated as true). For example

thisvar = false;
if ~thisvar; fprintf('thisvar is false'); end
thisvar is false
thisvar = 0;
if ~thisvar; fprintf('thisvar is false'); end
thisvar is false

As to why it still works even when truncated to 'uniform', it's hard to say since cellfun() is a built-in and the code isn't visible. That said, a lot of the input parsing for other functions do often allow undocumented abbreviations of parameter names. In fact, it appears that the tests that are used are simply to test that the argument is a char vector matching the characters in the name 'uniformoutput'. The shortest char vector that would meet these requirements is 'un', which seems to work.

MarshallSc 2021-7-17