Introduction

In analysis of any experimental data it is useful to check what is written in data files. To perform this check LCLS users need in flexible interactive tool. In this note we describe the Event display which works with HDF5 files. Before developing this Event display we have evaluated a couple of currently available generic tools which also work with HDF5 data presentation, HDFView and ViTables. Both of these tools have numerous pros and cons, but definitely, as is they can not cover all LCLS-specific graphical demands. After discussion of the platform for the event display we came to conclusion that the most clean and compact code could be written on Python with broad exploitation of standard libraries for graphics and GUIs, such as matplotlib and PyQt4, respectively. Below we overview the features and current status of this Event display project.

Event display features

This program is designed to access the LCLS data in HDF5 files and present them in printable or graphical formats. Currently the Event display can perform many tasks, as follows.

Select the input HDF5 file
Display entire HDF5 file structure
Print attributes and data structure of each HDF5 item (group or data set)
Select the data-records for graphical presentation
Select type of figures to be rendered
- Image and spectra for any camera
- Image and spectra for CSpad detector
- X, Y, R, and ? projections of any 2D images (not implemented yet)
- Waveforms
- Correlations between any scalar parameters (not implemented yet)
Event averaging
Event selection using thresholds in images

How to get a copy and run this program?

We assume that everything is set up to work on LCLS analysis farm,
otherwise see Computing and Account Setup.

Being on psana0### one has to get source code and build executable:

cd <your-favorite-directory>
newrel ana-current myVersionOfTheEventDisplay
cd myVersionOfTheEventDisplay
sit_setup
addpkg EventDisplay       (at this stage you need to have access to yakut.slac.stanford.edu)
scons

When these stages are passed successfully, program can be started by the command

evtdisplay

If you are going to use the HDF5 files from Lustre file system, this program should be run on psana0###.

Event Display GUIs

Execution of this program begins with displaying of the Main GUI. All other GUIs and plots can be lunched
by clicking on mouse starting from the Main GUI. Next section explains what can be done through the Event display system of GUIs.