Spectra  1.0.1 Header-only C++ Library for Large Scale Eigenvalue Problems
Enumerations

## Enumerations

enum class  Spectra::CompInfo {
Successful ,
NotComputed ,
NotConverging ,
NumericalIssue
}

enum class  Spectra::GEigsMode {
Cholesky ,
RegularInverse ,
ShiftInvert ,
Buckling ,
Cayley
}

enum class  Spectra::SortRule {
LargestMagn ,
LargestReal ,
LargestImag ,
LargestAlge ,
SmallestMagn ,
SmallestReal ,
SmallestImag ,
SmallestAlge ,
BothEnds
}

## Detailed Description

Enumeration types for the selection rule of eigenvalues.

## ◆ CompInfo

 enum Spectra::CompInfo
strong

The enumeration to report the status of computation.

Enumerator
Successful

Computation was successful.

NotComputed

Used in eigen solvers, indicating that computation has not been conducted. Users should call the compute() member function of solvers.

NotConverging

Used in eigen solvers, indicating that some eigenvalues did not converge. The compute() function returns the number of converged eigenvalues.

NumericalIssue

Used in various matrix factorization classes, for example in Cholesky decomposition it indicates that the matrix is not positive definite.

Definition at line 17 of file CompInfo.h.

## ◆ GEigsMode

 enum Spectra::GEigsMode
strong

The enumeration to specify the mode of generalized eigenvalue solver.

Enumerator
Cholesky

Using Cholesky decomposition to solve generalized eigenvalues.

RegularInverse

Regular inverse mode for generalized eigenvalue solver.

ShiftInvert

Shift-and-invert mode for generalized eigenvalue solver.

Buckling

Buckling mode for generalized eigenvalue solver.

Cayley

Cayley transformation mode for generalized eigenvalue solver.

Definition at line 17 of file GEigsMode.h.

## ◆ SortRule

 enum Spectra::SortRule
strong

The enumeration of selection rules of desired eigenvalues.

Enumerator
LargestMagn

Select eigenvalues with largest magnitude. Magnitude means the absolute value for real numbers and norm for complex numbers. Applies to both symmetric and general eigen solvers.

LargestReal

Select eigenvalues with largest real part. Only for general eigen solvers.

LargestImag

Select eigenvalues with largest imaginary part (in magnitude). Only for general eigen solvers.

LargestAlge

Select eigenvalues with largest algebraic value, considering any negative sign. Only for symmetric eigen solvers.

SmallestMagn

Select eigenvalues with smallest magnitude. Applies to both symmetric and general eigen solvers.

SmallestReal

Select eigenvalues with smallest real part. Only for general eigen solvers.

SmallestImag

Select eigenvalues with smallest imaginary part (in magnitude). Only for general eigen solvers.

SmallestAlge

Select eigenvalues with smallest algebraic value. Only for symmetric eigen solvers.

BothEnds

Select eigenvalues half from each end of the spectrum. When nev is odd, compute more from the high end. Only for symmetric eigen solvers.

Definition at line 33 of file SelectionRule.h.