Static structure factor¶
The module computes the static structure factor
from the Fourier modes of a given pair of (partial) density fields,
and the total number of particles . The result is averaged over
wavevectors of similar magnitude according to the shells defined by
halmd.observables.utility.wavevector
.
For details see, e.g., Hansen & McDonald: Theory of simple liquids, chapter 4.1.
-
class
halmd.observables.
ssf
(args)¶ Construct instance of
halmd.observables.ssf
.Parameters: - args (table) – keyword arguments
- args.density_mode – instance(s) of
halmd.observables.density_mode
- args.norm (number) – normalisation factor
- args.label (string) – module label (optional)
Returns: instance of static structure factor module
The argument
density_mode
is an instance or a table of 1 or 2 instances ofhalmd.observables.density_mode
yielding the partial density modesand
. They must have been constructed with the same instance of
halmd.observables.utility.wavevector
. Passing only one instance implies.
The optional argument
label
defaults todensity_mode[1].label .. "/" .. density_mode[2].label
.-
disconnect
()¶ Disconnect static structure factor module from profiler.
-
sampler
¶ Callable that yields the static structure factor from the current density modes.
-
label
¶ The module label passed upon construction or derived from the density modes.
-
class
writer
(args)¶ Write time series of static structure factor to file.
Parameters: - args (table) – keyword arguments
- args.file – instance of file writer
- args.location (string table) – location within file (optional)
- args.every (number) – sampling interval
Returns: instance of density mode writer
The argument
location
specifies a path in a structured file format like H5MD given as a table of strings. It defaults to{"structure", self.label, "static_structure_factor"}
.-
disconnect
()¶ Disconnect static structure factor writer from observables sampler.