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# 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 10:15:07 -0500

```-
```
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
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