Initializing a ublas vector from a C array

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I’m not sure how your question relates to MATLAB/MEX, but a side note, you might want to know that MATLAB implements a copy-on-write strategy.

This means that when you copy an array for example, only some headers are actually copied, while the data itself is shared between the two arrays. And once one of them is modified, a copy of the data is actually made.

The following is a simluation of what might be happening under the hood (borrowed from this old post):

-----------------------------------------
>> a = [35.7 100.2 1.2e7];

 mxArray a
    pdata -----> 35.7 100.2 1.2e7
  crosslink=0

-----------------------------------------
>> b = a;

 mxArray a
    pdata -----> 35.7 100.2 1.2e7
  crosslink     / \
    |  / \       |
    |   |        |
    |   |        |
   \ /  |        |
   crosslink     |
 mxArray b       |
    pdata --------

-----------------------------------------
>> a(1) = 1;

mxArray a
    pdata -----> (1) 100.2 1.2e7
  crosslink=0


   crosslink=0
 mxArray b
    pdata ------> 35.7 100.2 1.2e7 ...

I know this doesn’t really answer your question, I just thought you might find the concept helpful.

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