NAME
VERSION
SYNOPSIS
DESCRIPTION
ATTRIBUTES
METHODS
SERIALIZATION AND DESERIALIZATION
CONFIGURATION AND ENVIRONMENT
DEPENDENCIES
BUGS AND LIMITATIONS
AUTHOR
LICENCE AND COPYRIGHT

NAME

Demeter::VPath - Virtual paths for EXAFS visualization

VERSION

This documentation refers to Demeter version 0.9.26.

SYNOPSIS

Build a virtual path from several real paths.

  my $vpath = Demeter::VPath->new(name => "my virtual path");
  $vpath -> include($path1, $path3, $path12);
  $vpath -> plot('R');

DESCRIPTION

A fit can involve a lot of paths. It is often useful to make a plot showing your data and its fit along with some of the paths that went into the fit. In a fit with lots of small paths, one might want to convey a sense of how several small paths affect the fit in aggregate. A plot showing each individual path will be messy and won't actually convey the point.

The VPath object is tool for addressing this. A VPath, or "virtual path", is a sum of two or more paths which is Fourier transformed and plotted as a single object. This cleans up your plot and more directly conveys the effect of the constituent paths on the fit.

This object carries a sufficiently low-overhead that you can safely destroy one and recreate it with a different list of paths. That will usually be easier than managing the content of the paths atrtibute (although you can certainly do so, if you prefer).

The VPath can also be saved to a column data file using the normal save and save_many methods.

ATTRIBUTES

Along with the standard attributes of a Demeter object (name, plottable, data, and so on), a VPath has the following:

paths

This is the sole user-servicable attribute specific to this class. Its accessor returns the list of Path objects making up this VPath.

  my @list_of_paths = $vpath -> paths;

See the include method for how to set this attribute properly.

You should set the name attribute to something useful. By default, the name will be "virtual path". The data attribute is set to be the same as the first Path in the list of paths contributing to the VPath.

The methods push_paths, pop_paths, shift_paths, unshift_paths, and clear_paths are defined to operate on this list. But they should be used with caution. The inlcude and clear methods below are wrappers around these which perform additional chores necessary for the correct operation of the VPath object.

METHODS

include

Use this method to put one or more Path objects in the VPath's list of paths:

  $vpath -> include($some_path);
    or
  $vpath -> include(@a_bunch_of_paths);

While you could, in principle, use the paths attribute accessor and its service methods to set the list of paths, this method performs the additional chore of correctly setting the data attribute.

clear

This method empties out the path list and unsets the data attribute without destroying the VPath object.

  $vpath -> clear;
  ## @{ $vpath->paths } is now ();

first

Return the first path in the VPath's path list;

  $first_one = $vpath -> first;

This is used in the prep_vpath template.

SERIALIZATION AND DESERIALIZATION

Good question ...

CONFIGURATION AND ENVIRONMENT

See Demeter::Config for a description of the configuration system.

DEPENDENCIES

Demeter's dependencies are in the Build.PL file.

BUGS AND LIMITATIONS

Please report problems to the Ifeffit Mailing List (http://cars9.uchicago.edu/mailman/listinfo/ifeffit/)

Patches are welcome.

AUTHOR

Bruce Ravel (http://bruceravel.github.io/home)

http://bruceravel.github.io/demeter/

LICENCE AND COPYRIGHT

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.