Eigen Command

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This command is used to perform the analysis.

eigen <$solver> $numEigenvalues

$numEigenvalues number of eigenvalues required
$solver optional string detailing type of solver: -genBandArpack, -symmBandLapack, -fullGenLapack (default: -genBandArpack)


a tcl string containg eigenvalues.


  1. The eigenvectors are stored at the nodes and can be printed out using a Node Recorder, the nodeEigenvector command, or the Print command.
  2. The default eigensolver is able to solve only for N-1 eigenvalues, where N is the number of inertial DOFs. When running into this limitation the -fullGenLapack solver can be used instead of the default Arpack solver.


<math> \left (K - \lambda M \right ) \Phi = 0 </math>


set eigenvalues [eigen 10];

Code Developed by: fmk