Eigen Command: Difference between revisions
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{| | {| | ||
| style="background: | | style="background:lightgreen; color:black; width:800px" | '''eigen <$solver> $numEigenvalues''' | ||
|} | |} | ||
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| style="width:150px" | '''$numEigenvalues''' || number of eigenvalues required | | style="width:150px" | '''$numEigenvalues''' || number of eigenvalues required | ||
|- | |- | ||
| '''$solver'''|| optional string detailing type of solver: -genBandArpack, -fullGenLapack (default: -genBandArpack) | |||
| '''$solver'''|| optional string detailing type of solver | |||
|} | |} | ||
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NOTES: | NOTES: | ||
#The eigenvectors are stored at the nodes and can be printed out using a Node Recorder, the nodeEigenvector command, or the Print command. | # The eigenvectors are stored at the nodes and can be printed out using a Node Recorder, the nodeEigenvector command, or the Print command. | ||
# The default eigensolver is able to solve only for N-1 eigenvalues, where N is the number of inertial DOFs. When running into this limitation the -fullGenLapack solver can be used instead of the default Arpack solver. | |||
# The -fullGenLapack option is VERY SLOW for moderate to large models | |||
THEORY: | THEORY: | ||
:<math> \left (K - \lambda | :<math> \left (K - \lambda M \right ) \Phi = 0 </math> | ||
---- | ---- | ||
| Line 42: | Line 38: | ||
EXAMPLE: | EXAMPLE: | ||
set eigenvalues [ | set eigenvalues [eigen 10]; | ||
Latest revision as of 19:38, 19 August 2022
- Command_Manual
- Tcl Commands
- Modeling_Commands
- model
- uniaxialMaterial
- ndMaterial
- frictionModel
- section
- geometricTransf
- element
- node
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- Analysis Commands
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- DataBase Commands
This command is used to perform the analysis.
| eigen <$solver> $numEigenvalues |
| $numEigenvalues | number of eigenvalues required |
| $solver | optional string detailing type of solver: -genBandArpack, -fullGenLapack (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.
- The -fullGenLapack option is VERY SLOW for moderate to large models
THEORY:
- <math> \left (K - \lambda M \right ) \Phi = 0 </math>
EXAMPLE:
set eigenvalues [eigen 10];
Code Developed by: fmk