NEPNLEIGSSetRKShifts#

Sets a list of shifts to be used in the Rational Krylov method.

Synopsis#

#include "slepcnep.h" 
PetscErrorCode NEPNLEIGSSetRKShifts(NEP nep,PetscInt ns,PetscScalar shifts[])

Collective

Input Parameters#

  • nep - the nonlinear eigensolver context

  • ns - number of shifts

  • shifts - array of scalar values specifying the shifts

Options Database Key#

  • -nep_nleigs_rk_shifts <s0,s1,…> - sets the list of shifts

Notes#

If only one shift is provided, the built subspace is equivalent to shift-and-invert Krylov-Schur (provided that the absolute convergence criterion is used). Otherwise, the rational Krylov variant is run.

In the case of real scalars, complex shifts are not allowed. In the command line, a comma-separated list of complex values can be provided with the format [+/-][realnumber][+/-]realnumberi with no spaces, e.g. -nep_nleigs_rk_shifts 1.0+2.0i,1.5+2.0i,1.0+1.5i.

Use ns=0 to remove previously set shifts.

See Also#

NEP: Nonlinear Eigenvalue Problems, NEPNLEIGS, NEPNLEIGSGetRKShifts()

Level#

advanced

Location#

src/nep/impls/nleigs/nleigs.c

Implementations#

NEPNLEIGSSetRKShifts_NLEIGS() in src/nep/impls/nleigs/nleigs.c

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