Re: st: 3200 conformability error when writing to stata variable from mata

[Nick Cox <njcoxstata@gmail.com>]

In the problematic code you are asking Mata to put a vector of length  
20 into a variable with 74 observations. By Mata's rules the two are  
not conformable.
It might be suggested that a reasonable default would be that Mata put  
this vector in the first 20 observations. Or again, into the last 20  
observations. However, defaults such as those are not part of the Mata- 
Stata game. You need to be explicit about which observations are to  
receive the values in this vector.
Nick

On 14 Sep 2012, at 05:38, Aaron Kirkman <ak1795mailserv@gmail.com>  
wrote:
> I have a simple piece of code that replicates a -generate- statement
> (as an example) to write a new variable to an existing dataset. Under
> certain circumstances, however, the code throws a runtime error:
>
> st_store():  3200  conformability error
>                 <istmt>:     -  function returned error
>
>
> This is the code that returns an error:
> ##
>
> sysuse auto, clear
> mata
> mata clear
> pmg = 1 :: 20
> st_addvar("long","pmg")
> st_store(.,"pmg",pmg)
> end
>
> ##
>
> The following code, however, is successful (I removed the views from
> the last example because they are not relevant):
>
> ##
>
> sysuse auto, clear
> mata
> mata clear
> st_view(mpg=0,.,"mpg")
> st_view(weight=0,.,"weight")
> pmg=weight:*mpg
> st_addvar("long","pmg")
> st_store(.,"pmg",pmg)
> end
>
> ##
>
> As far as I can tell, the matrix -pmg- is of the same form in each
> example, although it differs in the number of observations. Both are
> column vectors containing only integers, so I'm not sure what is
> causing the problem. What is causing the error in the first
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