Qing Xie wrote:
> Hi,
> I'm trying to get the difference map by subtracting the native
> electron density map from the complex electron density map. MAPMASK
> has a function of ADD/MULT, but I don't know how to use it?
> Any other ways to attack this problem in real space?
>
> Thanks in advance,
>
> Qing
>
>
Yes - mapmask will do it providing you ADD SCALE -1 fpr one map then
MAP ADD
But there isa no adjustment for scaling one map to the other.
It is better to do a difference map use F1=Fcomplex and F2 = Fnative and
the phases/FOM from the model.
(see Map Utilities)
Make sure you have scaled F1 and F2 together (scaleit will do it) AFTER
calculating the PHIC/FOM.
Most SF generating programs (REFMAC, SFALL, maybe Clipper utilitiy?)
output a Fobs scaled to Fcalc so you need to rescale the other F again..
Eleanor
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