Software for Liquid Argon time projection chambers

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Running Jobs

This page describes the job configuration file (often, in jargon: FHiCL file) and how to run a job using one.

It is assumed that you have previously read the Quick-start guide to using and developing LArSoft code.

The Job Configuration

Once a base release is set up, it is easy to run a job. The basic unit for running a job is the job-control script, written in the FHICL language. The FHICL language provides a simple mechanism for including parameter set configurations from different files such that many job configuration files can use the same configuration for a module or service.

There is also a FHiCL quick start guide available for more details.

Key Concepts in FHiCL

There are a few key concepts to writing a FHICL job control script. In order, they are

  1. Including previously defined configurations for services and modules from other files. This is done using #include statements. Be sure you don’t have any trailing space or tab characters on the #include line.
  2. Service block, denoted by services: { } This block will contain configurations for ART specific services such as the TFileService and the RandomNumberGenerator. It also contains the configuration of LArSoft specific services1.
  3. Source block, denoted by source: { }. This block tells the job what kind of source to expect (EmptyEvent in the case of Monte Carlo generation, RootInput in the case of anything downstream of a Monte Carlo generator or reconstruction, and specific modules for data from the detector), the file name for the input source if appropriate, and how many events to process. Both the file name and number of events to process can be specified on the command line.
  4. Output block, denoted by outputs: { } This block tells the job what kind of output to make, i.e. RootOutput, and what the name of the output file should be. The output file name can be specified on the command line. It is possible to define more than one output file if one wanted to run a job that produced different output files based on filter criteria - i.e. empty events are put in one file and events with neutrinos in them are put in another. Multiple output files can only be specified in the job configuration file, not from the command line.
  5. Physics block, denoted by physics: { } This block is where all producer, analyzer, and filter modules are configured. Sequences of producer and filter modules to run is defined in user-named paths in this block. The list of analyzers and output modules to run is defined in a separate user-named path. The block also defines two keyword parameters, trigger_paths and end_paths. trigger_paths contains all producer and filter paths to run, and end_paths contains the analyzer and output path.

Comments may be included in FHiCL configuration files using the “#” character. The #include is a keyword so that the parser knows not to ignore what comes after “#include2”.

FHiCL Rules

There are a few of rules to keep in mind about FHiCL:

Example configuration file: detsimmodules.fcl

An example of a file with predefined configurations for modules is in the larsim/DetSim/detsimmodules.fcl file.
All the definitions are inside a prologue block.
The following is an excerpt taken from LArSoft v05_00_00 (experiments now use their specific detsimmodule_Xxxx.fcl configuration file though):


  module_type:        "SimWire"
  DriftEModuleLabel:  "largeant"
  NoiseFact:           0.0132      # Noise Scale
  NoiseWidth:         62.4         # Exponential Noise width (kHz)
  LowCutoff:           7.5         # Low frequency filter cutoff (kHz)
  FieldBins:          75
  Col3DCorrection:    2.5
  Ind3DCorrection:    1.5
  ColFieldRespAmp:    0.0354
  IndFieldRespAmp:    0.018
  ShapeTimeConst:     [ 3000., 900. ]
  CompressionType:    "none"

argoneut_simwireana: @local::standard_simwireana

### ... and more configurations ...


Configuring the message service

Several standard configurations for the message service are in lardata/Utilities/messageservice.fcl. There is one configuration for each level of message output - Debug, Info, Warning, and Error. These configurations will be applied to each message level that is specified and those of higher priority. For example, the Info configuration will print out Info, Warning and Error level messages while the Warning configuration only print outs Warning and Error level messages. The “standard” debug configurations will cause the messages to go to a specified output file, debug.log. The Error configuration redirect to standard error stream (like std::cerr), while the others print into the standard output (std::cout). All impose some limits on the repetition of some frequent messages.
Remember that to use one of these “standard” configurations you need to include it in your FCL file: they are standard, not default.
If you want to define your own configuration, please take a look at the comments in lardata/Utilities/messageservice.fcl file to determine how to do so.

Examples of how to include the usual use of the message service configurations are in the example files below.

To get a different level of output from just one module (say DBSCAN) one would do:

  # Load the service that manages root files for histograms.
  TFileService: { fileName: "reco_hist.root" }
  Timing:       {}
  RandomNumberGenerator: {} #ART native random number generator

  # configure the message service with the INFO for DBSCAN
  # and WARNING level for everything else
  message: { 
    destinations: {  
      infomsg: {
        type: "cout"
        threshold: "INFO"
        append: true
        category: {
           DBSCAN: {
             reportEvery: 1
      warningmsg: {
        type:      "cout"   
        threshold: "WARNING"
        append:    true        
        categories: {
          default: {
            limit:       1000   
            timespan:    60    
        } # end categories
      } # end warningmsg
    } # end destinations
  } # end standard_warning

  user:         @local::argoneut_services        

Debug messages

Note that debugging messages are treated in a special way:

  1. there are two ways to print a debug message in the code: by using mf::LogDebug, and by using LOG_DEBUG macro; the messages using the latter will not be present when a non-debug qualifier (prof and opt) is used. In fact, no code is generated at all from a LOG_DEBUG call unless using a debug qualified build
  2. debug output from modules is selectively enabled by the debugModules list; to enable all the messages, use debugModules: [ "*" ]

Also remember that, depending on the configuration, the debug output could be not shown on screen, but only stored in a file (e.g. debug.log).

Example job script: prodgenie.fcl

To see an example job script to produce Monte Carlo events, go to: larsim/EventGenerator/GENIE/prodgenie.fcl . The job defined by this script will generate neutrino interactions using GENIE, run them through Geant4, do the electron transport and then simulate the electronics.

How to override a default parameter

If you want to override a default parameter that has been included from a predefined parameter set, you must specify which parameter and its value as

mainBlock.subBlock.label.parameterName: newValue


These lines must go after the mainBlock and be outside of any other block.

For example, if one wanted to change the default value of the HitsModuleLabel parameter in the dbcluster module instance in the previous section, one would put

physics.producers.dbcluster.HitsModuleLabel: "differentHitModuleLabel"

Note that FHiCL allows for completely replacing a list but not for changing its size (i.e., it’s not possible to add an element to an existing list).

This behavior is general: FHiCL only allows to replace elements. For example, if one wants to change both eps and epstwo parameters,

physics.producers.dbcluster.DBScanAlg: { # WRONG!!!
  eps:    1.1
  epstwo: 1.6

will not work, because it is replacing the whole physics.producers.dbcluster.DBScanAlg parameter set, thus removing e.g. the parameter minPts.
The correct way to change parameters is to think of that as replacing them, and to point exactly at each of them:

physics.producers.dbcluster.DBScanAlg.eps:    1.1
physics.producers.dbcluster.DBScanAlg.epstwo: 1.6

will leave the other parameters (e.g., minPts) unchanged.

fhicl Emacs syntax highlighting

If you use Emacs as your editor, you can put the following into your .emacs file in your home directory to cause it to display .fcl files with syntax highlighting

(setq fclKeywords
  ;; This, due to poor language design, conflicts with comments and fails
  ("#include" . font-lock-keyword-face)
  ("@local" . font-lock-keyword-face)
  ;; All these names are magic, I think

("process_name:\\|services:\\|source:\\|outputs:\\|physics\\|producers:\\|filters:\\|analyzers:" . font-lock-builtin-face)
  ("true\\|false" . font-lock-builtin-face)
  ;; Variable definitions are followed by colons

  ("[a-zA-Z0-9_]*:" . font-lock-variable-name-face)

;; Python mode gets us comment handling and indentation at colons

(define-derived-mode fcl-mode python-mode
 (setq mode-name "FHICL")
 (setq font-lock-defaults '(fclKeywords))
;;  (setq tab-width 2) ;; Doesn't seem to work


(add-to-list 'auto-mode-alist '("\\.fcl\\'" . fcl-mode))

Please use only spaces for alignment: it’s not the perfect solution, but it makes people using different editors see the same code alignment.

Executable and command line options

Currently there is one executable to run in LArSoft. The executable to run a typical reconstruction or analysis job is lar which is placed in the user’s path by the setup script. To see what options are available do

$ lar -h

Some of the most useful options (from lar version v1_17_05) are:

Running a Job

To run the job defined by the script above, do

$ lar -c job/prodgenie.fcl

One can stop a job in two ways:

  1. press + once: the job will complete at the end of the current module. If the job is running in the background type `kill -9 %jobID` on the command line.
  2. press + twice: the job should stop immediately and, depending on the shall settings, might produce a core dump.

If you want to have your job keep running even if you get disconnected from a remote session, depending on your shell you might need to start it with:

$ nohup lar job/prodgenie.fcl >& pg.out

To stop such a job, then do

$ pgrep lar # to find the job ID (use ps to disambiguate if more than one lar process are running)
$ kill -INT jobID

One can print out the configuration of the job without starting the executable by:

$ ART_DEBUG_CONFIG=1 lar -c prodgenie.fcl

in bash, or

> env ART_DEBUG_CONFIG=1 lar -c prodgenie.fcl

in C-shell, which produces the output

** ART_DEBUG_CONFIG is defined: config debug output follows **
all_modules: [ "out1"
             , "daq"
             , "generator"
             , "largeant"
             , "rns"
outputs: { out1: { fileName: "genie_gen.root"
                   module_label: "out1"
                   module_type: "RootOutput"
physics: { end_paths: [ "stream1" ]
           producers: { daq: { Col3DCorrection: 2.5
                               ColFieldRespAmp: 3.54e-2
                               CompressionType: "none"
                               DriftEModuleLabel: "largeant"
                               FieldBins: 75
                               Ind3DCorrection: 1.5
                               IndFieldRespAmp: 1.8e-2
                               LowCutoff: 7.5
                               NoiseFact: 1.32e-1
                               NoiseWidth: 6.24e1
                               ResponseFile: "shape-argo.root"
                               ShapeTimeConst: [ 3000
                                               , 900
                               module_label: "daq"
                               module_type: "SimWireT962"
                        generator: { BeamCenter: [ -1400
                                                 , -350
                                                 , 0

This functionality is particularly helpful when trying to debug what input parameters were passed to the job.

Why did my job fail?

In case of failure, art usually provides some information about the failure.

If a job fails, look at the warnings printed to the screen or any output log files.

Also check in the breaking changes page for information about problems (and solutions) caused by changes to the code.

You can ask for help from the larsoft mailing list, or open a issue in the appropriate tracker (usually the LArSoft one).
The usual bug report rules apply: include at least

If a bug should be reported to the art-users list, attach the complete output of the job to the email.

Submitting Jobs to the compute farms

We have to find out where the page with the submission instructions went (TODO!).

  1. In old FHiCL files you will notice that LArSoft and in general non-art service configuration is enclosed in a user block, that is now deprecated. 

  2. Note that the FHiCL parser can’t recognize a comment on the same line as a #include directive.