MODAL ANALYSIS
The choice of a method of computation depends on several factors like the model size, the number of required modes...
There are two groups of methods:
Transformation: the eigenvalue equation is transformed into a form from which eigenvalues can be easily extracted. Givens and Householder are transformation methods.
Tracking: eigenvalues are extracted one at a time using an iterative procedure. Inverse power is a tracking method.
Lanczos is the more utilised method, which overcomes the limitations and combines the best features of the other methods.