fft {<xray-fft-statement>} end
<xray-fft-statement> :==
gridsize=<real>
Gridsize for transform will be gridsize * high-resolution
Default=0.333333
bscalefactor=<real>
Temperature factor (in A^2) scale to decrease aliasing effects.
Default=20
elimit=<real>
Ratio of atomic form factor at maximum and at rcut in
e-logarithmic units. Default=7
memory=<integer>
Space allocation for fft matrix the default is 500000 but if
automemory is enabled the default becomes 2000000.
automemory=<logical>
If true memory allocation space for fft is determined automatically.
If false the allocation defined by memory is used.
prime=<integer>
Maximum prime to be used in fft factorization.
The default is machine-dependent.
base=<integer>
Minimum prime to be used in fft factorization.
Default is machine-dependent.
avoid=<integer>
Avoid this factor in physical dimension of 3-d matrix
due to data bank conflicts on some shared memory machines.
Default is machine-dependent.