Re: Eigenvalues, any suggestions?
- To: mathgroup at smc.vnet.net
- Subject: [mg43624] Re: Eigenvalues, any suggestions?
- From: "Eckhard Hennig" <aidev at n-o-s-p-a-m.kaninkolo.de>
- Date: Fri, 26 Sep 2003 04:45:37 -0400 (EDT)
- Organization: 1&1 Internet AG
- References: <bkp2hl$d2r$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"AC" <ancow65 at yahoo.com> schrieb im Newsbeitrag news:bkp2hl$d2r$1 at smc.vnet.net... > In[1]:= > data={XX\[Rule]100.,YY\[Rule]100.,ZZ\[Rule]100., > XY\[Rule]0.,XZ\[Rule]0.,YZ\[Rule]0.}; > > In[2]:= > Eigenvalues[{{XX,XY,XZ},{XY,YY,YZ},{XZ,YZ,ZZ}}]/.data > > \!\(Power::"infy" \(\(:\)\(\ \)\) " > Infinite expression \!\(1\/0.`\^\(1/3\)\) encountered."\) Just move the closing bracket a few positions to the right to evaluate the matrix numerically *before* calculating the eigenvalues: Eigenvalues[{{XX,XY,XZ},{XY,YY,YZ},{XZ,YZ,ZZ}} /.data] Note that in your formulation, the eigenvalues were first computed symbolically, and the solutions involve cubic root expressions (hence the 0^1/3 errors). Hint: check the output of this command: Eigenvalues[{{XX,XY,XZ},{XY,YY,YZ},{XZ,YZ,ZZ}}] Best regards, Eckhard -- Dr.-Ing. Eckhard Hennig www.kaninkolo.de/ai aidev \at kaninkolo \dot de