Eigen Algorithm

Eigen Algorithm = {cayley | si}

Description/Usage

This optional card is used by the ARPACK eigensolver to select between the Cayley transformation algorithm and the shift and invert algorithm. When cayley is selected, Eigen Cayley Sigma card and Eigen Cayley Mu are the two shift parameters. When the shift and invert (default) algorithm is used, Eigen Cayley Sigma is the single shift parameter. The valid options are:

cayley

Cayley transformation algorithm.

si

Shift and invert algorithm.

The default value is si.

Examples

Here is a sample card:

Eigen Algorithm = cayley

Technical Discussion

When the Cayley algorithm is selected, the relative values of Eigen Cayley Sigma and Eigen Cayley Mu also determine which of the two Cayley transformation methods (A or B) is used by ARPACK.

Another use of this card is to determine whether eggroll or ARPACK will be used for non-continuation problems: If this card is present with a valid option, ARPACK will be used; otherwise eggroll will be used. Continuation runs with LOCA will always use ARPACK, and non-LOCA continuation runs cannot be combined with stability analysis.

This card is not applicable to the eggroll eigensolver, which uses only the shift and invert algorithm.

Theory

No Theory.

FAQs

No FAQs.

References

No References.