Using XED as a Filter

Here is an example command file that uses XED as a filter:

define event_loop
        call inp
        call upk
        call cal

        call ftt
        if_not_ok quit_event

        call xed
        if_not_ok quit_event
        call out(1)
end_def

$multi_output_sel $pel_args
file inp 1 input_file.zdab
file out 1 xed_filtered_events.zdab format=$zdab_only 

@run_snodb

In this example, events are input from 'input_qfile.zdab', calibrated, fitted, and passed to XED.

The user can advance through events by either pressing the 'Next/Pass' button, or the 'Next/Fail' button. Pressing the 'Next/Pass' button results in a call to OUT, so the event is saved. Pressing the 'Next/Fail' button means the test 'if_not_ok quit_event' returns back to the start of the event loop.

This is a very easy way to sort data with XED. This is a very flexible tool, just as FLT is. Some other ideas for use include:

• Running time-consuming calibrations, fits or classifiers on the event before calling XED again.
• Including or not including an ntuple in the hbook file, by conditionally allowing ANL to be called or not.
• Setting DARN bits (although is is better accomplished via the XED-DMM interface, described below).
• Counting certain types of event by looking at the output of XED on termination.