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[ccp4bb]: fffear 1.1
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fffear 1.1.0: ---- Fast Fourier FEAture Recognition ---
Version 1.1 of fffear is available.
fffear is a program which implements Fast Fourier FEAture Recognition,
as a means to locate small molecular fragments in noisy electron
density maps. The method was inspired by Essens (Kleywegt G. J., Jones
T. A., Acta Cryst. D53, 179-185), and re-implemented in reciprocal
space (Cowtan K. D., Acta Cryst. D54, 750-756) to achieve improved
speed and discrimination.
Version 1.1 is *much* faster than 1.0, with speed improving by
between 1.2 and 15 times. Facilities for MR and NCS calculations
have also improved, with options to refine an approximate initial
operator or perform a translation search with a fixed orientation.
The changes from 1.0 are as follows:
1. fffear now uses crystallographic symmetry to reduce the orientation
search. This reduces the calculation time by roughly the number of
non-primitive symmetries for non-cubic spacegroups, i.e. 4 times
speed increase in P212121.
2. A near-constant metric sampling of orientation space has been
adopted to further reduce the number of orientations, resulting in
a further 20% speed improvement in all spacegroups.
3. Options to pre-rotate the search model and limit the orientation
search range have been introduced to allow refinement of an
initial orientation estimate.
4. Form factors may now be input for fitting electron microscopy or
5. The log file is now clean html.
This software is licensed under part (ii) of the CCP4 license with
the addendum that the license is only valid if the `No Warranty'
clause is binding. Thus the software may not be used in Virginia or
any other US State which has passed the UCITA legislation without
first arranging a written license with me. Users in other states,
particularly Maryland, California, and Oklahoma, should check the
status of this legislation before downloading the software.
> ftp ftp.ysbl.york.ac.uk
ftp > cd pub/ccp4
ftp > get fffear.tar.gz
ftp > quit
> gunzip fffear.tar.gz
> tar xvf fffear.tar
> cd fffear/src
Note: CCP4v4 must be installed and setup before you compile fffear.
If you wish to use fffear for NCS/cross crystal searches, you must
use the latest version of `maprot' with map cutting facilities,
available in the same directory in maputils.tar.gz.