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From |
Steven Samuels <sjsamuels@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Mata not computing eigenvectors/values |

Date |
Mon, 10 Jan 2011 14:14:16 -0500 |

Zachary

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.

- 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'tworking, theproblem might have something to do with the "A" matrix being rankdeficient.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 theaforementionedA 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: owner-statalist@hsphsun2.harvard.edu (on behalf of Zachary Neal <zpneal@gmail.com>) Subject: st: Mata not computing eigenvectors/values To: statalist@hsphsun2.harvard.edu 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 zpneal@msu.edu 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 zpneal@msu.edu 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/

**Follow-Ups**:**Re: st: Mata not computing eigenvectors/values***From:*Zachary Neal <zpneal@gmail.com>

**References**:**st: Mata not computing eigenvectors/values***From:*Zachary Neal <zpneal@gmail.com>

**Re: st: Mata not computing eigenvectors/values***From:*Matthew J Baker <matthew.baker@hunter.cuny.edu>

**Re: st: Mata not computing eigenvectors/values***From:*Steven Samuels <sjsamuels@gmail.com>

**Re: st: Mata not computing eigenvectors/values***From:*Zachary Neal <zpneal@gmail.com>

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