!EIGEN¶
Parameter settings of eigenvalue analysis
Parameter¶
N/A
** 2nd line or later **
| Parameter Name | Attributions | Contents |
|---|---|---|
| NSET | I | No. of eigenvalue |
| LCZTOL | R | Allowance (Default: 1.0e-8) |
| LCZMAX | I | Max No. of iterations (Default: 60) |
| SIGMA | R | Shift value \(\sigma\) (Default: 0.01) |
Example of Use¶
SIGMA normally does not need to be changed from its default value of 0.01. However, it may be necessary to modify this value when performing a free-free eigenvalue analysis (i.e., an eigenvalue analysis without any constraint conditions).
If a free-free eigenvalue analysis is performed and a 0 Hz eigenvalue appears in the computed eigenvalue solutions, increasing SIGMA to a value larger than 0.01 (for example, 1.0) may resolve the issue.