why it will go wrong using 'cell'?

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warnerchang el 31 de Mzo. de 2022
Comentada: warnerchang el 1 de Abr. de 2022
Recently, I ran two codes as follow:
% it will go wrong
  2 comentarios
KSSV el 31 de Mzo. de 2022
The difference is the space allocated for each.
whos a b
Name Size Bytes Class Attributes a 1x2 208 cell b 1x2 16 cell
warnerchang el 31 de Mzo. de 2022
however,what happened behind cell function? As far as I know, a = {[],[]} and b = cell(1,2) should get the same result.

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Jan el 31 de Mzo. de 2022
Editada: Jan el 31 de Mzo. de 2022
I confirm, that this is an inconsistent behavior.
a = {[], []};
b = cell(1, 2);
isequal(a, b)
ans = logical
a{1}([]) = [] % Working: Nothing is deleted as expected
a = 1×2 cell array
{0×0 double} {0×0 double}
b{1}([]) = [] % Failing:
Deletion requires an existing variable.
Both methods create a cell array of the same size, but cell() fills the elements with a NULL pointers, while {[], []} creates empty matrices. Matlab should treat NULL pointers as empty matrices, but as you see in this example, this exception has been forgotten sometimes. You cannot detect the NULL points from inside Matlab, but on the C level this is easy. KSSV's method to check the used memory is a strong hint also.
Report this bug to MathWorks. The function for deleting will be updated than to catch this exception.

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