Parallel Multiprojection Preconditioned Methods Based on Subspace Compression

Table 5

Convergence behavior and parallel performance of the PPGMRES() method, in conjunction with the MPMSC scheme for various problems.

MPMSC	Cores/subdomains
	64	128	256	512	1024
atmosmodd
Iterations	5 ()	6 ()	6 ()	6 ()	7 ()
Total-Time	759.43	255.30	137.97	108.40	109.37
atmosmodl
Iterations	1 ()	1 ()	1 ()	1 ()	1 ()
Total-Time	439.56	271.09	77.05	43.85	36.38
tmt_sym
Iterations	22 ()	19 ()	13 ()	12 ()	11 ()
Total-Time	272.72	175.99	117.74	105.86	96.67
apache2
Iterations	8 ()	8 ()	7 ()	7 ()	5 ()
Total-Time	189.46	105.15	74.75	66.76	50.49
cage14
Iterations	—	—	0 ()	0 ()	0 ()
Total-Time	—	—	1,296.23	196.70	62.69

“—”: memory limits were reached in the initialization phase.