. Author manuscript; available in PMC: 2015 Jul 9.

Published in final edited form as: J Struct Biol. 2013 Feb 11;182(2):93–105. doi: 10.1016/j.jsb.2013.01.011

Table 4.

Time efficiency tests for aligning two volumes on a single processor of Alpha server ES40, processor EV6.8AL, 833 Mhz. PBVA with 15 projections was used in the test. The search ranges are specified in columns 1 and 2. The translational range for the full 6D cross-correlation differs slightly between direct volume alignment and PBVA, since PBVA searches on a polar grid, while the other algorithms use a Cartesian grid. Column CC: Direct volume alignment without missing data correction, Column “Normalized CC”: Direct volume alignment with correction for missing data. PBVA is a factor of 220 to 160 times faster than a full 3D volume alignment. Even after optimization of the full alignment algorithm the factor should still be substantial.

	Rotational Search	Translational Search	CC	Normalized CC	PBVA
Rough search	25×13×25	7×7×7	11:06:42	15:21:49
Rough search	25×13×25	Radius 10			0:04:06
Fine search	23×23×23	7×7×7	16:39:09	22:47:47
Fine search	23×23×23	Radius 10			0:04:53
Rotation alignment			x	x	0:01:22
Translation alignment			x	x	0:00:01
Total time			27:45:51	38:09:36	0:10:22