Petroulas Pavlos <[email protected]> asks,
> If I am in Stata and for memory preserving reasons I enter Mata (instead of
> using Stata's matrix language) do certain matrix operation, I would then
> like to exit Mata but keep the matrices in Stata's memory: How do I do
> this? (I.e with mat dir in Statas matrix language I would like for some
> matrices that I've created in Mata to show up)
He is asking about this in the context of using Mata interactively.
Matrices during a Stata session
-------------------------------
Mata clears itself when you say to do so, which you can do in
three ways:
1. Typing -mata clear- to the Mata (:) prompt.
2. Typing -clear mata- to the Stata (.) prompt.
3. Typing -clear all- to the Stata (.) prompt.
Mata does not clear itself automatically. That means Mata remembers
matrices between Mata sessions within the same Stata session.
. mata
: A = (1,2,3)
: end
. use mydata, clear
. mata
: A
<matrix A will be displayed>
: end
Matrices across Stata sessions
------------------------------
You can interactively save matrices in a file. Here's an example:
. mata
: A = (1,2,3)
: B = (4,5)
: mata matsave mymats A B
: mata clear
: A
<A will not be found>
: mata matuse mymats
: A
<A will be displayed>
: B
<B will be displayed>
: end
-mata matsave mymats A B- will create file mymats.mmat. .mmat is the
default file extension.
You can type -mata matdescribe mymats- to find out what is in a file
without loading it.
See -help mata matsave-.
Advanced stuff
--------------
-mata matsave-, -mata matdescribe-, and -mata matuse- are for
interactive use. If you want to save matrices in a file within a
program, see -help mata fopen()-.
As a matter of fact, -mata matsave-, -mata matdescribe-, and -mata matuse-
are written in terms of -fopen()-. If you interested, see
. viewsoure mata_matsave.ado
. viewsoure mata_matuse.ado
. viewsoure mata_matdescribe.ado
. viewsource mmat_.mata
Easiest is simply to type -help mata matsave-, scroll down, and click
on the filenames under heading "Source code".
-- Bill
[email protected]
*
* 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/
