Analysis of Augmented Krylov Subspace Methods

  • Authors:
  • Yousef Saad

  • Affiliations:
  • -

  • Venue:
  • SIAM Journal on Matrix Analysis and Applications
  • Year:
  • 1997

Quantified Score

Hi-index 0.00

Visualization

Abstract

Residual norm estimates are derived for a general class of methods based on projection techniques on subspaces of the form $ K_m + {\cal W}$, where $K_m$ is the standard Krylov subspace associated with the original linear system and ${\cal W}$ is some other subspace. These "augmented Krylov subspace methods" include eigenvalue deflation techniques as well as block-Krylov methods. Residual bounds are established which suggest a convergence rate similar to one obtained by removing the components of the initial residual vector associated with the eigenvalues closest to zero. Both the symmetric and nonsymmetric cases are analyzed.