Compute center of gravity and radius of gyration of a 3-D
density distribution.
SEE ALSO
CG [center of gravity] CG 3 [center of gravity - radius of gyration] CG PH [center of gravity - phase approximation]
USAGE
.OPERATION: CG 3S X10,X11,X12,X20
.THREED FILE: 3DQ003
[Enter name of file containing the 3-D density distribution.]
THRESHOLD: 0.53
[Only data above the threshold will be used in computation.]
NOTES
The coordinates of the center of gravity, with respect to
the center at (NSAM/2 + 1, NROW/2 + 1, NSLICE/2 +1), and
the radius of gyration are printed out and put into the
first four (optional) registers appearing on the command
line.
For this operation, data above the threshold are
replaced by a uniform density. Thus, the 3-D object is
treated as a solid body without internal density
variations.
For the definition of the radius of gyration, see
International Tables of Crystallography, vol. III, p327.