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Re: st: Basic Matrix Definition Question


From   "Thomas Jacobs" <thomasjacobs@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Basic Matrix Definition Question
Date   Mon, 15 Oct 2007 14:03:51 -0500

Dear Abdel,

Thanks very much.  I totally missed the mkmat command in the manual.
Although I probably made the example too simple, I am trying to write
a program to solve for two equations in two unknowns so I am building
a partial derivative matrix for inverting.  I calculate each of the 4
partials as variables and then combine them into a matrix.  I was
stuck on the create matrix step.  Using local macros worked as well
with a matrix command.  I assume that I would need to first create two
column vectors from 2 of the four variables and then combine these
with another mkmat command.

Does the HTH after the byvar=x,y line in your mata example have a
specific meaning?

Sincerely,

Tom

On 10/15/07, Abdel Rahmen El Lahga <rahmen.lahga@gmail.com> wrote:
> I dont understand what your are trying to do here a short ansewer is
> gen x=1
> gen y=2
> mkmat x y , matrix(byvar)
> matrix list byvar
> In mata the logic is different
> mata:
> x=1
> y=2
> byvar=x,y
> HTH
> AbdelRahmen
>
> 2007/10/15, Thomas Jacobs <thomasjacobs@gmail.com>:
> > I am trying to create a matrix from a couple of variables.  Let's make
> > this simple.
> >
> > I can hand enter
> >
> > matrix byhand = (1,2)
> >
> > but if I do
> >
> > gen x =1
> > gen y =2
> > matrix byvar = (x,y)
> >
> > I get x not found even though display x gives me 1.
> >
> > What am I missing here and is there a workaround?  Thanks very much.
> >
> > Sincerely,
> >
> > Tom
> >
> > --
> > Thomas Jacobs
> > *
> > *   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/
> >
>
>
> --
> AbdelRahmen El Lahga
> *
> *   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/
>


-- 
Thomas Jacobs
*
*   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/



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