| Tartalmi leírás: |
The rate of convergence of the conjugate gradient method takes place in essen-
tially three phases, with respectively a sublinear, a linear and a superlinear rate.
The paper examines when the superlinear phase is reached. To do this, two methods
are used. One is based on the K-condition number, thereby separating the eigenval-
ues in three sets: small and large outliers and intermediate eigenvalues. The other
is based on annihilating polynomials for the eigenvalues and, assuming various an-
alytical distributions of them, thereby using certain refined estimates. The results
are illustrated for some typical distributions of eigenvalues and with some numerical
tests.
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