[petsc-users] GMRES convergence

Colin McAuliffe cjm2176 at columbia.edu
Thu Apr 18 11:22:59 CDT 2013

Hello all,

I am testing out a few linear solvers on a small (1052 by 1052)  
matrix. Using unpreconditioned GMRES with -ksp_gmres_restart 10000,  
GMRES still takes many times more than 1052 iterations to converge.  
Shouldn't it be the case that for a n by n matrix, n iterations of  
GMRES will give a full factorization of the matrix?


Colin McAuliffe
PhD Candidate
Columbia University
Department of Civil Engineering and Engineering Mechanics

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