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Just adjust the scale parameters in the FFT script - mF1-nF2 option. Eleanor Armando Albert de la Cruz wrote: > Does anyone have got a script to compute 3fo2fc map with CCP4? > Armando > > > El 29/07/2010, a las 23:38, Ian Tickle escribió: > >> On Thu, Jul 29, 2010 at 8:25 PM, Pavel Afonine <[log in to unmask]> wrote: >>> >>> Speaking of 3fo2fc or 5fo3fc, ... etc maps (see classic works on this >>> published 30+ years ago), I guess the main rationale for using them >>> in those >>> cases arises from the facts that >>> >>> 2Fo-Fc = Fo + (Fo-Fc), >>> 3Fo-2Fc = Fo +2(Fo-Fc) >>> >>> To be precise, it is actually >>> >>> 2mFo-DFc for acentric reflections >>> and mFo for centric reflections >> >> I prefer to think of it rather as >> >> 2mFo - DFc = DFc + 2(mFo-DFc) for acentrics and >> mFo = DFc + (mFo-DFc) for centrics. >> >> Then it also becomes clear that to be consistent the corresponding >> difference map coefficients should be 2(mFo-DFc) for acentrics and >> (mFo-DFc) for centrics. >> >> Cheers >> >> -- Ian