# Enum SELECT_EIGENVALUE

## Description

The enumeration of selection rules of desired eigenvalues.

## Values

 LARGEST_MAGN = 0 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. Mentioned in:Getting Started / Examples LARGEST_REAL Select eigenvalues with largest real part. Only for general eigen solvers. LARGEST_IMAG Select eigenvalues with largest imaginary part (in magnitude). Only for general eigen solvers. LARGEST_ALGE Select eigenvalues with largest algebraic value, considering any negative sign. Only for symmetric eigen solvers. Mentioned in:Getting Started / Examples SMALLEST_MAGN Select eigenvalues with smallest magnitude. Applies to both symmetric and general eigen solvers. SMALLEST_REAL Select eigenvalues with smallest real part. Only for general eigen solvers. SMALLEST_IMAG Select eigenvalues with smallest imaginary part (in magnitude). Only for general eigen solvers. SMALLEST_ALGE Select eigenvalues with smallest algebraic value. Only for symmetric eigen solvers. BOTH_ENDS Select eigenvalues half from each end of the spectrum. When nev is odd, compute more from the high end. Only for symmetric eigen solvers.

## Source

enum SELECT_EIGENVALUE
{
LARGEST_MAGN = 0,  ///< 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.

LARGEST_REAL,      ///< Select eigenvalues with largest real part. Only for general eigen solvers.

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

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

SMALLEST_MAGN,     ///< Select eigenvalues with smallest magnitude. Applies to both symmetric and general
///< eigen solvers.

SMALLEST_REAL,     ///< Select eigenvalues with smallest real part. Only for general eigen solvers.

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

SMALLEST_ALGE,     ///< Select eigenvalues with smallest algebraic value. Only for symmetric eigen solvers.

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