Restarted block-GMRES with deflation of eigenvalues
Applied Numerical Mathematics - 6th IMACS International symposium on iterative methods in scientific computing
Choice of initial guess in iterative solution of series of systems arising in fluid flow simulations
Journal of Computational Physics
Journal of Computational and Applied Mathematics
Restarted block-GMRES with deflation of eigenvalues
Applied Numerical Mathematics - 6th IMACS International symposium on iterative methods in scientific computing
SIAM Journal on Scientific Computing
SIAM Journal on Scientific Computing
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Many scientific applications require one to solve successively linear systems Ax=b with different right-hand sides $b$ and a symmetric positive definite matrix A. The conjugate gradient method applied to the first system generates a Krylov subspace which can be efficiently recycled thanks to orthogonal projections in subsequent systems. A modified conjugate gradient method is then applied with a specific initial guess and initial descent direction and a modified descent direction during the iterations. This paper gives new theoretical results for this method and proposes a new version. Numerical experiments show the efficacy of our method even for quite different right-hand sides.