Eigen Command
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This command is used to perform the analysis.
| eigen <$type> <$solver> $numEigenvalues |
| $numEigenvalues | number of eigenvalues required |
| $type | optional string detailing type of eigen analysis: -standard or -generalized (default: -generalized) |
| $solver | optional string detailing type of solver: -genBandArpack, -fullGenLapack, -UmfPack, -SuperLU (default: -genBandArpack) |
RETURNS:
a tcl string containg eigenvalues.
NOTES:
- The eigenvectors are stored at the nodes and can be printed out using a Node Recorder, the nodeEigenvector command, or the Print command.
- 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.
THEORY:
Standard Problem:
- <math> \left (K - \lambda I \right ) \Phi = 0 </math>
Generalized Problem:
- <math> \left (K - \lambda M \right ) \Phi = 0 </math>
EXAMPLE:
set eigenvalues [eigen 10];
Code Developed by: fmk