checkCIF procedure


PURPOSE: To check that _reflns_threshold_expression contains a multiplier which is below the limit.


IF _reflns_threshold_expression ~ 'I'
OR _reflns_threshold_expression ~ 'F^2^'
_reflns_threshold_expression >= '6' issue ALERT A
   "Alert A The _reflns_threshold_multiplier given is >= 6"
_reflns_threshold_expression >= '5' issue ALERT B
   "Alert B The _reflns_threshold_multiplier given is >= 5"
_reflns_threshold_expression >= '4' issue ALERT C}
   "Alert C The _reflns_threshold_multiplier given is >= 4"
IF _reflns_threshold_expression ~ 'F'
_reflns_threshold_expression >= '12' issue ALERT A
   "Alert A The _reflns_threshold_multiplier given is >= 12"
_reflns_threshold_expression >= '10' issue ALERT B
   "Alert B The _reflns_threshold_multiplier given is >= 10"
_reflns_threshold_expression >= '8' issue ALERT C}
   "Alert C The _reflns_threshold_multiplier given is >= 8"
The multiplier in _reflns_threshold_expression is used to select the significantly intense reflections for use in the calculation of the regular R-factor given in _refile_ls_R_factor_gt. Older refinement programs, particularly those based on F, may use ONLY the intense reflections selected by this criterion. Therefore it is highly desirable to keep the multiplier in _reflns_threshold_expression as small as possible. Typically a value of 2 or less is used in the expressions 'I > 2\s(I)' or 'F^2^ > 2\s(F^2^)', or 4 or less in 'F > 4\s(F)'.
IF _reflns_threshold_expression is not present issue ALERT C
   "Alert C Test not performed"
You have not specified _reflns_threshold_expression or the text cannot be interpreted. This item is compulsory and should be of the form 'I > x\s(I)' or 'F^2^ > x\s(F^2^)' or 'F > x\s(F)'.

The multiplier, x, is typically 2 or less. If you selected zero for the multiplier, you still must provide the expression for _reflns_threshold_expression; e.g. 'I > 0\s(I)'

IF _reflns_observed_criterion has been used issue a General ALERT
   "_reflns_observed_criterion is an old dataname which has been superceded by _reflns_threshold_expression"
You are using an "old-fashioned", but still legal data name: _reflns_observed_criterion. Please update the item to match the currently preferred name of _reflns_threshold_expression. To ease this problem for the future, it is recommended that you upgrade or modify your CIF generating software accordingly.

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