checkCIF procedure

PLAT930

 Check the proposed Twin Law. The entry in () represents the proposed rotation
 axis in reciprocal space and the one in [] the corresponding rotation is
 direct space. The relevant Twin Matrix can be found in the file '.ckf'.  
 NOTE: This analysis is based on F(obs)**2/F(calc)**2 differences with
 F(calc)**2 data taken from the '.fcf' file (i.e. F(obs), F(calc) listing).   
 ALERT_930 is expected to generate an related ALERT-931 as well.