st: Question concerning pointers in Mata

[Matthew J Baker <matthew.baker@hunter.cuny.edu>]

Hello Everyone - 

I'm curious why the following two snippets of mata code produce 
different results. The observation is that if one defines a 
temporary matrix and then "points" to this matrix, the result is 
different than if one just simply "points" to the definition. 
Accordingly, I'm a bit curious about how exactly the pointer and 
the pointed is storing results. Here is an example:

/* Beginning of example */

mata
Y=J(10,1,NULL)
for (k=1;k<=10;k++) {
Y[k]=&J(k,k,1)
}
Z=J(10,1,NULL)
for (k=1;k<=10;k++) {
Temp=J(k,k,1)
Z[k]=&Temp
}
/* Compare contents of Y[1] and Z[1]  */
*Y[1]
*Z[1]

/* End of example */

Any insights appreciated!

Best,

Matt Baker

Dr. Matthew J. Baker
Department of Economics
Hunter College and the Graduate Center, CUNY
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