| Description | Perl tools for X-ray Absorption Spectroscopy |
Demeter::FPath - Filtered paths
This documentation refers to Demeter version 0.9.26.
Build a single scattering path by Fourier filtering chi(k) data:
my $fpath = Demeter::FPath->new(source => $data_object,
name => "my filtered path",
absorber => 'Cu',
scatterer => 'O',
reff => 2.1,
n => 6,
);
$fpath -> plot('R');This object handles the creation of a path filtered from chi(k) data. This could be used to create an empirical standard that can be used in Artemis in the same way as any other Path or Path-like object. It could also be used to create a single path-like object from some kind of theoretical model -- for instance, a histogram created from a molecular dynamics simulation.
The difference between a Path and FPath is the provenance of the path. For a Path object, you must specify either a ScatteringPath object as the sp attribute or you must set the folder and file attributes to point at the location of a feffNNNN.dat file.
For an FPath object, you set none of those attributes yourself (they all get set, but not by you). Instead, you specify the source from which the filterted path will be extracted, the absorber, scatterer, reff, and n attributes, which describe the basic features of the path being generated. Demeter will then generate a single scattering path from the Data object at the approximate distance in the data. The resulting path will have a natural degeneracy of 1, which can, of course, be overriden by the n attribute.
FPath objects are plotted just like any Path object, as shown in the synopsis above. They are used in fits in the same way as ordinary Path objects. That is, the paths attribute of the Fit object takes a reference to a list of Path and/or FPath (or other path-like) objects.
As with any Moose object, the attribute names are the name of the accessor methods.
This extends Demeter::Path. Along with the standard attributes of any Demeter object (name, plottable, source, and so on), and of the Path object, an SSPath has the following:
sourceThis takes the reference to the Data object from which the path will be extracted.
absorberThe atomic species of the absorbing atom. This can be the name (e.g. copper), the symbol (e.g. Cu), or Z number (e.g. 29).
scattererThe atomic species of the scattering atom. This can be the name (e.g. oxygen), the symbol (e.g. O), or Z number (e.g. 8).
reffThe approximate path length of the shell being filtered from the data.
There are no outward-looking methods for the FPath object beyond those inherited from the Path object. All methods in this module are used behind the scenes and need never be called by the user.
Good question ...
See Demeter::Config for a description of the configuration system.
Demeter's dependencies are in the Build.PL file.
Sanity checking, for instance that the data is set before anything is done, that reff is sensible
Serialization by itself and in a fit.
Please report problems to the Ifeffit Mailing List (http://cars9.uchicago.edu/mailman/listinfo/ifeffit/)
Patches are welcome.
Bruce Ravel, http://bruceravel.github.io/home
http://bruceravel.github.io/demeter/
Copyright (c) 2006-2018 Bruce Ravel (http://bruceravel.github.io/home). All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlgpl.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.