Summary: Things to be aware of before executing the ExtSym executable from within the DASH GUI.
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Taking the example of executing ExtSym through the CCDC DASH software. As is probably the case for all powder decomposition programs, including DASH, an expert user will on average produce better Pawley fits than a novice user and the better the fit to the data the better the resulting ExtSym output. By experience it has been found that novice users of the DASH software are likely to accept a Pawley fit that an expert DASH user would classify as rather poor. This will in general not affect the results obtained from global optimisation runs performed with DASH, but will affect the ExtSym outcome for reasons which are explained here. Therefore before hitting the ExtSym button in DASH (named 'Run>' in the 'Pawley Refinement Step 2' DASH wizard) it is strongly recommended that good effort is put into obtaining the best possible DASH Pawley fit.
August 2008: As noted by a referee to the paper [1] there is a bug in DASH which resets trigonal Pawley refined data to hexagonal. As a result of this, for versions prior to August 2008, don't use ExtSym from within DASH if you have a trigonal crystal system.