Eigen Tolerance

Eigen Tolerance = <float>

Description/Usage

This optional card specifies the absolute residual tolerance used in the eggroll eigensolver. Valid input are defined as:

tol>=0.0

The termination criteria used within the eigensolver.

The default value of tol is 1.0e-6.

Examples

Here is a sample card:

Eigen Tolerance = 1.0e-16

Technical Discussion

The value of tol specifies a termination condition used within the eigensolver. At the time of this writing it was difficult to guarantee that a small tol would lead to very accurate eigenpairs with the eggroll solver. This is one of the primary reasons for switching to the ARPACK eigensolver. The correspondence of “internal residual” to “error in eigenpair” is even more difficult with the generalized eigenvalue problem than “residual” to “error in solution vector” with regular linear solvers.

This card is not applicable to the ARPACK eigensolver, which uses a relative tolerance (see the Eigen Relative tolerance card).

Theory

No Theory.

FAQs

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References

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