checkCIF procedure

PLAT934

 This ALERT reports on the number of reflections for which I(obs) and I(calc)   
 differ more that 10 times SigmaW. (The latter being the square root of 
 1.0/weight for that reflection in the L.S. refinement). The reason for those   
 deviations should be investigated. When shown to be systematic errors, those
 reflections are best removed from the refinement and their omission from the
 refinement reported in the experimental section of an associated paper.