st: mata st_view

[Kit Baum <baum@bc.edu>]

Carl said

After I run this the matrix a in mata is correct, but the variables
in the stata data set haven't been
changed.

I would appreciate any help correcting my error. Thanks.


Carl has been bitten by the feature that any command that creates a  
new matrix in Mata will not populate a view of the same name. He also  
misunderstood _equilr, which returns r rather than taking it as input.

. webuse grunfeld


. mata
------------------------------------------------- mata (type end to  
exit) ---------
: st_view(a=.,.,("invest","mvalue","kstock"))

: b=a

: r=J(0,0,.)

: _equilr(b,r)

:    a[.,.]=b

: end
------------------------------------------------------------------------ 
-----------

. l invest mvalue kstock

     +--------------------------------+
     |   invest     mvalue     kstock |
     |--------------------------------|
  1. | .1031671          1   .0009095 |
  2. | .0840466          1   .0112834 |
  3. | .0762191          1   .0291251 |
  4. | .0922928          1    .074923 |
  5. | .0766948          1   .0471576 |
     |--------------------------------|
  6. | .0993131          1   .0446177 |
  7. | .1124978          1   .0560731 |
  8. | .1380969          1   .0936161 |
  9. | .1232454          1   .0651504 |
10. |   .12502          1   .0460348 |
...

Note that you cannot place a in the _equilr statement, as that  
creates a new matrix a rather than addressing the view and modifying  
the underlying variables.



Kit Baum, Boston College Economics
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html


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