Fast construction of voxel-level functional connectivity graphs

BMC Neuroscience

Table 1 Performance comparison for computation of correlation matrices

\|N\|/10³		corrcoef	corr		IPN_fastCorr			pcc/naive		pcc/SSE2		pcc/AVX		tetracc/32		tetracc/128
	m[GB]	t[s]	t[s]	s[×]	t[s]	s[×]	m[GB]	t[s]	s[×]	t[s]	s[×]	t[s]	s[×]	t[s]	s[×]	t[s]	s[×]
10	0.4	2.3	1.8	1.29	1.5	1.55	0.2	7.2	0.32	1.7	1.39	1.1	2.16	0.4	5.65	0.2	12.58
20	1.5	9.1	6.8	1.34	5.6	1.63	0.7	28.8	0.32	6.7	1.35	4.3	2.11	1.6	5.71	0.7	13.17
30	3.4	20.2	14.9	1.35	12.4	1.63	1.7	64.9	0.31	15.1	1.34	9.7	2.09	3.5	5.70	1.5	13.33
40	6.0	36.1	26.8	1.35	22.0	1.64	3.0	115.4	0.31	26.9	1.34	17.3	2.09	6.3	5.76	2.7	13.55
50	9.3	55.9	41.5	1.35	34.3	1.63	4.7	180.3	0.31	42.2	1.32	27.0	2.07	9.8	5.72	4.1	13.53
60	13.4	80.3	59.5	1.35	49.3	1.63	6.7	259.4	0.31	60.5	1.33	38.7	2.07	14.0	5.73	5.9	13.57
70	18.3	109.5	80.9	1.35	67.0	1.63	9.1	352.9	0.31	82.4	1.33	52.6	2.08	19.1	5.75	8.0	13.65
80	23.8	180.1	143.4	1.26	87.5	2.06	11.9	461.4	0.39	107.7	1.67	69.1	2.61	24.9	7.24	10.4	17.24
90	30.2						15.1	584.3		137.1		87.9		31.4		13.2
100	37.3						18.6	721.0		168.7		107.8		38.7		16.3
110	45.1						22.5	872.1		203.1		130.3		46.8		19.6
120	53.6						26.8	1037.6		242.0		154.9		55.6		23.4
130	63.0						31.5	1217.5		284.3		181.6		65.2		27.4
140	73.0						36.5	1411.7		329.4		210.2		75.6		31.7
150	83.8						41.9	1620.2		377.9		241.3		86.7		36.4
160	95.4						47.7	1845.5		430.7		276.4		98.6		41.4
170	107.7						53.8	2085.0		487.8		313.2		111.3		46.7

Results are averages from 10 runs on a desktop computer with an Intel(R) Core(TM) i7-3960X CPU (3.3GHz) and 64GB main memory. All programs were restricted to one CPU core. Length of time series T was fixed at T=200. |N|: number of nodes. The programs corrcoef (Matlab built-in), corr (Matlab Statistics Toolbox), IPN_fastCorr (X.N. Zuo), and pcc (three variants) computed C_r, while tetracc (two variants) computed $C_{r_{t}}$ . m [GB]: memory requirements for result in GB; t [s]: elapsed time in seconds; s [ ×]: speedup relative to corrcoef.

ISSN: 1471-2202