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Pointless: Difference between revisions
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(add the I2 versus C2 stuff to the "Attention" section - thanks to Ethan Merrit) |
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will make an R-factor search for the correct origin. | will make an R-factor search for the correct origin. | ||
'''Attention''': the space group number that pointless writes into the logfile (e.g. "17") is the generic one (as in the International Tables vol A), not the specific one (which could be 17, | '''Attention''': the space group number that pointless writes into the logfile (e.g. "17") is the generic one (as in the International Tables vol A), not the specific one (which could be 17, 1017 or 2017) that is used as a special convention within CCP4 to encode which of a,b and c is the two-fold screw axis. At the same time, pointless re-indexes orthorhombic such that a<b<c : this is what is called "cell-based setting" in the pointless documentation, and unfortunately it's the default. However, users of [[XDSCONV]] want the "symmetry-based setting" because XDSCONV does not understand 1017 and 2017 (and those numbers are not even in the logfile, only in the MTZ file which is not used by XDSCONV anyway). This also affects the distinction between space groups C2 and I2. | ||
This is discussed under the headings "A note on setting conventions" and "SETTING CELL_BASED || SYMMETRY-BASED || C2" in the [http://www.ccp4.ac.uk/html/pointless.html pointless documentation]. | This is discussed under the headings "A note on setting conventions" and "SETTING CELL_BASED || SYMMETRY-BASED || C2" in the [http://www.ccp4.ac.uk/html/pointless.html pointless documentation]. | ||