4.3. Mode object

One Mode object is created automatically when an instance of a DEMETER program is started. The Mode object is the thing that keeps track of the state of everything in a DEMETER program. For example, attributes of the Mode are used to set the disposal channel and the template set.

To make the Mode object readily accessible at all times in your program, the mo method is a method of the base class and is inherited by all DEMETER objects. Thus, given any object, you can “find” the Mode object like so:

$the_mode_object = $any_object -> mo;

To choose disposal channels, use the set_mode method. For instance, to direct output to both IFEFFIT and to the screen (which is useful for debugging purposes)

$any_object -> set_mode(backend=>1, screen=>1);

To then turn off screen output:

$any_object -> set_mode(screen=>0);

The Mode object does a lot more than that. It keeps count of the number of data sets used in a fitting model so that IFEFFIT's feffit command works properly for a multiple data set fit. It keeps track of the number of fits that have been run in the current instance of the DEMETER program. And it keeps track of the indexing of Path objects. It also keeps track of the directory in which the DEMETER program started and of the current working directory as the program proceeds. For a full list of the atttributes, see the documentation for the Demeter::Mode object.

Other attributes keep track of every object created during and instance of DEMETER:

my @all_atoms  = @{ $any_object->mo->Atoms };
my @all_data   = @{ $any_object->mo->Data };
my @all_feff   = @{ $any_object->mo->Feff };
my @all_fit    = @{ $any_object->mo->Fit };
my @all_gds    = @{ $any_object->mo->GDS };
my @all_path   = @{ $any_object->mo->Path };
my @all_plot   = @{ $any_object->mo->Plot };
##  ... and so on ... one for each kind of object

The accessor returns an array reference. The @{ } syntax dereferences the array. References in perl are explained in detail in the perlref document.

The everything method returns references to every object created during the instance of the DEMETER program.

my @all_of_them = $any_object->mo->everything;

The fetch method can be used to find a particular object given the value of its group attribute, which is a randmoly generated string that gets made when the object is created. This is most useful when deserializing a save file. This example finds a Data object:

my $object = $any_object->mo->fetch("Data", $group_name);

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