=head1 ARTEMIS: The Path Page

B<ARTEMIS> - The path page

The path page is displayed whenever a B<Feff> path is selected from
the Data and Paths List.  This page is used to establish the math
expressions of the path parameters for this path.

At the top of the page is a line identifying which B<Feff> calculation
this path is from.  Below that are three toggles.  One is used to
include of inlcude or exclude the path from use in the fit.  There are
many other ways in B<Artemis> to include and exclude paths other than
to use this toggle.  See L<The Feff interpretation page|artemis_intrp>
and C<artemis_menubar> for more discussion of this.  Also
Control-t is the same as clicking this toggle.

The second toggle is used to specify paths that you would like plotted
after a fit (or sum of paths) is finished.  By default, the data and
the fit (or sum) is plotted after the fit (or sum) and no paths are
plotted.  Any paths selected for plotting will be added to the plot
after the fit (or sum) is finished.

The third toggle is used to set which path is the default path for
evaluation of Def parameters after the fit.  It is possible to write
math expressions which evaluate differently for different paths.  An
example might be a math expression using the C<reff> parameter.  For
any such Def parameters, it is necessary to tell B<Artemis> which path
should be used for the reporting of those parameters in the log file.
The default is to use the first path listed in the Data and Paths
List. 

Below that is a box which summarizes the path.  This gives some
statistics about the path as well as displaying a color-coded "map" of
the scattering path.  The central atom is always displayed in red
text.  Other atoms are in black text.  The grey text shows the length
and scattering angle of each leg of the path.  In the case of a
high-order multiple scattering path which has legs which have a
non-zero Eulerian eta angle between them, the eta angle will be
displayed as well.  If that last sentence was gibberish, it suffices
to know that paths of that sort are almost never observable in real
EXAFS data.

At the bottom of the page is the list of path parameters.  This is the
most important section of the page because it is here that the details
of the fitting model are realized.  There is an entry box for each of
the various types of path parameters.  The math expression
approporiate for each parameter should be entered in the entry box.

When a B<Feff> calculation is imported into B<Artemis>, a set of
automatic parameters are generated, entered into the list on the
Guess, Def, Set page, and entered into the path parameetr boxes for
each path imported.  The default behavior of B<Artemis> is to generate
a set of parameters appropriate for a simple, single scattering, first
shell fit.  While it might be OK to immediately click the big green
button, most fitting models will require substantial editing.

The right mouse button serves many important purposes on the path
page.  Clicking the right mouse button anywhere in one of the entry
boxes will highlight the word underneath the cursor and post a menu.
The entries in the menu are for for defining the word as a parameter
on the Guess, Def, Set page.  For each parameter type there is the
option of jumping or staying.  In either case, the parameter is
defined and added to the list on the GDS page.  For jumping, the GDS
page is then displayed.  For staying, the current path page remains
displayed.

Right clicking on one of the path parameter labels will post a menu of
functions related to defining path parameter math expressions.  The
"Edit" option will pop up a dialog used for entering a math expression
and then optionally exporting its value to other paths.  The "Clear"
option doies just that.

The various "Export" options are ways of constraining path parameters
to be the same for other paths.  The "Grab" options make the current
path parameter the same as the path parameter in the previous or
following path.

The "sigma^2" label has some additional options.  These insert the
syntactically correct text appropriate to using either the Correlated
Debye or single frequency Einstein models for the sigma^2 of the
path.

To enable the display of spaces for the C<dphase>, C<k_array>,
C<amp_array>, or C<phase_array> path parameters, you must click on the
"Extended path parameters" button in the Paths menu.




=over 5

=item

L<Back to the main document|artemis>

=back

