SHELX/Platon OMIT Script

[wlewis]

I threw this together this afternoon as I didn't want to trawl through 2000 reflections lines to find the reflections to OMIT in SHELX. This script takes the CKF file from Platon (Cif check reflection report) and finds all the reflections where RatioW > 10 or < -10, and also any reflections where Ratio < -100 (tagged with a ? in the file), and writes these to FILE.OMIT, where the contents can be directly pasted into a SHELX instruction file.

Save as a python file (.py) and run from the command line:

Code: Select all

"""
Reads in a CKF and gets the reflections to be omitted from Section 2.
Runs from the command line with the file stem, and outputs filestem.omit as a text file.
"""

import sys

try:
    _file_stem = sys.argv[1]
    with open('{}.ckf'.format(_file_stem), 'r') as handle:
        _ckf_full = handle.read()
except IndexError as e:
    print("You haven't provided a file stem to run this script on.")
    sys.exit()
except FileNotFoundError as e:
    print("The file '{}.ckf' cannot be found. Check the spelling and remember to omit '.ckf', you only need to provide the filestem.".format(_file_stem))
    sys.exit()
    
_section2 = _ckf_full.split("Section")[2].split('\n')[6:-8]

_results_indices = []

for line in _section2:
    # test for Ratio < -100
    if line[63:64] == '?':
        _results_indices.append(line[5:17])
    # test for RatioW <-10 or > 10
    elif abs(float(line.split()[-1])) >= 10.0:
        _results_indices.append(line[5:17])

if len(_results_indices) == 0:
    print('No reflections found to OMIT!')
else:
    _output_string = 'OMIT ' + "\nOMIT ".join(_results_indices)
    with open('{}.omit'.format(_file_stem), 'w') as handle:
        handle.write(_output_string)
    print("OMITted reflections written to {}.omit".format(_file_stem))