In the current version of Stata, there
is a Mata solution for this.
In Stata 8, which I guess you
are using, I don't think there is
an exact equivalent to the Matlab construct.
You would need a loop, something like this:
forval i = 1/`=rowsof(lambda)' {
<calculate whatever>
if z[`i'] == 0 lambda[`i'] = -normden(<whatever>)
}
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Jens
> Hainmueller
> Sent: 27 April 2005 22:08
> To: [email protected]
> Subject: st: access subsets of a matrix
>
>
> Hi,
>
> I am new to Stata programming so I have a problem to
> translate the following
> line of mathlab code into Stata code.
>
> lambda(z==0) = - normpdf(X(z==0,:)*gamma)
>
> Here lambda is an (nx1) matrix, X is (nxk), gamma is (kx1), z
> is (nx1), and
> for example X(z==0) denotes subset of the matrix X for which
> (z==1), i.e.
> the condition in parenthesis holds true.
>
> In Stata, how can I access this subset of my X matrix? It should be
> something like:
>
> matrix lambda = -normde(X[if z==1]*gamma)
>
> but I can't Stata to access the matrix subsets as I need it.
> Thanks for your
> help.
>
> Best,
> Jens
>
>
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
