MATLAB: How the command whos works

MATLABmemory allocationwhos

I wonder how the command whos works. I have found:
Memory Usage Reported By the whos Function. The whos function displays the amount of memory consumed by any variable. For reasons of simplicity, whos reports only the memory used to store the actual data. It does not report storage for the array header, for example.
When I campute the memory used, for example, by a structure, it seems to me that head is included in the computation. For example, the formula for memory used structure array is fields x ((112 x array elements) + 64) + data that includes header. This memory corresponds exactly to the quantity in bytes given by the command whos.
I should conclude that whos gives the amount of memory including header. Where am I wrong?

Best Answer

This memory corresponds exactly to the quantity in bytes given by the command whos.
However you have to add to that the header size to hold information about the variable.
>> abc = 0
abc =
     0
>> whos abc
  Name      Size            Bytes  Class     Attributes
  abc       1x1                 8  double
abc is a double precision variable with one entry, and each double precision value needs 8 bytes. 1 row * 1 column * 8 bytes per entry = 8 bytes.
But storage is also occupied to hold the information that abc is 1 x 1, and that it is class double, and that it is not complex-valued, and that it is not global. whos does not report about that space.
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