Thanks Maarten,
I know what's "double" now.
And I have to corrected my expression in the previous email.
I first use -gen-... to calculate the elements of matrix M.
Then -mkmat h*, mat(M)- creat matrix M as T*10, where T is the mumver
of observations in the sample and there are 10 elements in the lower
triangle of the matrix for a specific period
Now I want to calculate the eigenvalues of the matrix for each time period:
mata:
M = st_matrix("M")
lambda = J(cols(M), 4, .)
for(t=1; t<=cols(M); t++) {
mt = invvech(M[., t])
lambda[t, .] = symeigenvalues(mt)
}
lambda
end
I am wondering if -M= = st_matrix("M")- here make sure it is a
*symmetric* matrix with the elements h11 h21... that I just generated.
Quoting Maarten buis <[email protected]>:
--- On Mon, 16/3/09, [email protected] wrote:
I am trying to make a *symmetic* matrix M like:
h11
h21 h22
h31 h32 h33
h41 h42 h43 h44
The codes:
gen double??? h11
gen double??? h21
gen double??? h31
gen double??? h41
gen double??? h22
gen double??? h32
gen double??? h42
gen double??? h33
gen double??? h43
gen double??? h44
mkmat h*, mat(M)
What's the difference with and without -double-?
If your aim is to create a symetric matrix, you
should not use -gen- anyhow. For more on how to
create a matrix see: -help matrix define-.
Hope this helps,
Maarten
Ps. the difference between -gen- and -gen double-
is explained in -help data types-
-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
