DSNHEP#
Dense Non-Hermitian Eigenvalue Problem.
Notes#
The problem is expressed as AX = XLambda, where A is the input matrix. Lambda is a diagonal matrix whose diagonal elements are the arguments of DSSolve(). After solve, A is overwritten with the upper quasi-triangular matrix T of the (real) Schur form, AQ = QT.
In the intermediate state A is reduced to upper Hessenberg form.
Computation of left eigenvectors is supported, but two-sided Krylov solvers usually rely on the related DSNHEPTS.
Used DS matrices#
DS_MAT_A - problem matrix
DS_MAT_Q - orthogonal/unitary transformation that reduces to Hessenberg form (intermediate step) or matrix of orthogonal Schur vectors
Implemented methods#
0 - Implicit QR (_hseqr)
See Also#
DSCreate(), DSSetType(), DSType
Level#
beginner
Location#
src/sys/classes/ds/impls/nhep/dsnhep.c
Index of all DS routines Table of Contents for all manual pages Index of all manual pages