Parallel RFSAI-BFGS Preconditioners for Large Symmetric Eigenproblems

Table 4

Influence of parameter 𝑘_max in the number of iterations of the Newton phase. Problem EMILIA-923 with 𝑝=64 processors.

𝑘max	Outer; its	MVP	CPU	Comments
0	431	15035	421.25	ITMAXPCG=100. No convergence within ITMAX =50. Final (average) residual norm of 10^−6
1	438	10899	336.74	No convergence within ITMAX =50. Final (average) residual norm of 10^−6
2	343	8329	258.22		No convergence within ITMAX =50. Final (average) residual norm of 10^−7
5	267	6839	198.19
10	204	5629	178.04
20	185	5616	164.18