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Re: st: RE: matrix commands


From   Jesper Kuhl <jesper.kuhl@economics.oxford.ac.uk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: matrix commands
Date   Mon, 7 Apr 2003 13:56:28 +0100 (BST)

Thanks for your reply, Nick, but how do I use "mkmat" to build a vector for a single obs.? "mkmat" is set up to build vectors for every variable or a matrix for all variables, as far as I can see.
Jesper

In message <EDEPKKNLOHMHPACNBOJEEEBJDDAA.n.j.cox@durham.ac.uk> statalist@hsphsun2.harvard.edu writes:
> Jesper Kuhl
> 
> > I am trying to use some of STATA's matrix commands, but do 
> > not really succeed, and hope some of you can give me a hint.
> > 
> > For my dataset I need a weighting factor (for every 
> > observation) calculated as
> > w=xi'(X'X)^-1 *xi, where X is a n*k matrix of all variables 
> > and all observations, and xi is a k*1 vector with the 
> > variable-values for a single observation. The middle part, 
> > (X'X)^-1, I can build using "matrix accum", but I can't get 
> > STATA to build a n*1 vector for every observation to pre- 
> > and postmultiply it with. Hope some of you might a suggestion.
> 
> Sounds like a case for -mkmat-. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
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