Eigen Command: Difference between revisions
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| style="width:150px" | '''$numEigenvalues''' || number of eigenvalues required | | style="width:150px" | '''$numEigenvalues''' || number of eigenvalues required | ||
|- | |- | ||
| '''$solver'''|| optional string detailing type of solver: -genBandArpack, | | '''$solver'''|| optional string detailing type of solver: -genBandArpack, -fullGenLapack (default: -genBandArpack) | ||
|} | |} | ||
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# 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 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 | |||
Latest revision as of 19:38, 19 August 2022
- Command_Manual
- Tcl Commands
- Modeling_Commands
- model
- uniaxialMaterial
- ndMaterial
- frictionModel
- section
- geometricTransf
- element
- node
- sp commands
- mp commands
- timeSeries
- pattern
- mass
- block commands
- region
- rayleigh
- Analysis Commands
- Output Commands
- Misc Commands
- 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