Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# Re: st: Mata not computing eigenvectors/values

 From Steven Samuels <[email protected]> To [email protected] Subject Re: st: Mata not computing eigenvectors/values Date Mon, 10 Jan 2011 14:14:16 -0500

```Zachary

```
What happens if you run Mathew's Mata commands (below)?. All three Mata versions and your Stata matrix commands produce the same values for me. In any case, perhaps there is something wrong with your Mata installation. Try re-installing Stata and bringing it up to date. If that doesn't work, I suggest that you contact support.
```
Steve

**********
eigensystem(A,X=.,L=.)
L'
lefteigensystem(A,Y=.,M=.)
M
***********

I would bet there
On Jan 10, 2011, at 1:39 PM, Zachary Neal wrote:

Sorry, that was a careless typo in my original message.  Steven is
right, it should have read:

symeigensystem(A,eigenvector,eigenvalue)

However, even with that correction, the outputs - eigenvector and
eigenvalue - are empty.

In contrast, if I attempt the same thing in stata, using:
matrix A = (0,0,0,0,0,1,0,1,0,0,0,0,0 \ ///
0,0,0,0,0,0,0,1,0,1,0,0,0 \ ///
0,0,0,1,0,1,1,0,1,0,1,1,1 \ ///
0,0,1,0,0,0,1,0,0,0,0,0,0 \ ///
0,0,0,0,0,0,0,1,0,0,0,0,0 \ ///
1,0,1,0,0,0,0,0,0,0,0,1,0 \ ///
0,0,1,1,0,0,0,0,0,0,0,0,0 \ ///
1,1,0,0,1,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0 \ ///
0,1,0,0,0,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,1,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0)
matrix symeigen eigenvectors eigenvalues = A
matrix list eigenvectors
matrix list eigenvalues

I am able to get the correct eigenvectors/values.

I'm still not sure why this seems to work in stata, but not in mata.

```
On Mon, Jan 10, 2011 at 10:15 AM, Steven Samuels <[email protected]> wrote:
```-
Zachary's code works for me if I substitute "A" for "network" in the
-symeigensytem()- command:

symeigensystem(A,eigenvector,eigenvalue)

Steve
Stata 11,1 OS X 10.5.8

On Jan 9, 2011, at 9:22 PM, Matthew J Baker wrote:

```
While I am not sure about why the symeigensystem command isn't working, the problem might have something to do with the "A" matrix being rank deficient.
```In any case, I find that the commands:

eigensystem(A,X=.,L=.)

and

lefteigensystem(A,Y=.,M=.)

```
both generate values for eigenvalues and eigenvectors for the aforementioned
```A matrix (collected in X and L, and Y and M, respectively).

Matt Baker

---- Original message ----
```
```
Date: Sun, 9 Jan 2011 17:45:19 -0500
From: [email protected] (on behalf of Zachary Neal
<[email protected]>)
Subject: st: Mata not computing eigenvectors/values
To: [email protected]

Running the commands below, mata does not yield any eigenvectors or
eigenvalues.  Computing eigenvectors/values in stata using matrix
symeigen seems to work without a problem.  Any help would be
appreciated.

mata
A = (0,0,0,0,0,1,0,1,0,0,0,0,0 \ ///
0,0,0,0,0,0,0,1,0,1,0,0,0 \ ///
0,0,0,1,0,1,1,0,1,0,1,1,1 \ ///
0,0,1,0,0,0,1,0,0,0,0,0,0 \ ///
0,0,0,0,0,0,0,1,0,0,0,0,0 \ ///
1,0,1,0,0,0,0,0,0,0,0,1,0 \ ///
0,0,1,1,0,0,0,0,0,0,0,0,0 \ ///
1,1,0,0,1,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0 \ ///
0,1,0,0,0,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,1,0,0,0,0,0,0,0 \ ///
0,0,1,0,0,0,0,0,0,0,0,0,0)
eigenvector = 0
eigenvalue = 0
symeigensystem(network,eigenvector,eigenvalue)
eigenvector
eigenvalue
end

--
Zachary Neal, PhD
Department of Sociology
Michigan State University
[email protected]
http://www.msu.edu/~zpneal
*
*   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/

*
*   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/

```
```

--
Zachary Neal, PhD
Department of Sociology
Michigan State University
[email protected]
http://www.msu.edu/~zpneal

*
*   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/
```

© Copyright 1996–2018 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index