Usability improvements


Have LArSoft as a friendly platform as possible for the Experiment members to

  • develop new analysis, reconstruction and simulation code for their Experiment
  • elevate that code to LArSoft standards for it to be merged for shared use by all LArSoft-using Experiments

Delivery time: June 2016 ("phase 1")

The plan

The potential targets are listed in the next section.
Due to the time span of this project, the first choices are reported in this table:

task delivery status
Code examples June 2106 three examples delivered
Creation of associations with data products June 2106 closing up
Services inheriting configuration from input file off schedule thinking ongoing...
Access to indirectly associated objects TBD scheduled to start on June/July


A number of people within a wide range of roles and expertise have been actively interviewed, and information has been collected during support requests.
The following topics emerged from this collection and some elaboration based on them.
Collection will continue, mostly as side effect of support requests.

This list is a draft, and it is still subject to discussion

Part of the interview results is strictly art framework improvements or feature extensions, and they haven't been listed here.


source contributors delivery effort status
Configuration language made parametric Amir Farbin not scheduled To do: channel the request from DUNE
Service configuration inheritance from input Herbert Greenlee not scheduled To do: submit art feature request

Configuration language

FHiCL configuration language could evolve to allow for parametric configuration that allows easy reuse of template configurations.
Despite some level of reusability, running for example two clustering modules differing by a single parameter and then a tracking module on each of them is more complicate than it should be.

The size of this request requires multi-month dedicated effort by FHiCL maintainers.

Services inheriting configuration from input file

Most of the services are required to have the same configuration as in the previous jobs the input comes from.
Failure to enforce this causes subtle errors. Multiple instances of this problem have been met in MicroBooNE, while dealing with develop-level reconstruction code on production level input files, and DUNE, when testing different geometries and settings.
The ability to read service configuration from input file would systematically solve this problem.

Discussion must start on how to approach the problem. A general solution from the art side may be advisable.
If art stakeholders are not interested, LArSoft can devise a proprietary solution.
Expected 3 week of work to get first service on proprietary solution; 0.5 to 1 week for every other.

Status and to do
  • submit feature request for the general solution to art and let the stakeholders decide whether they are interested;


source contributors delivery effort status
examples Michael Mooney LArSoft team 2-8 weeks1
(1) new data product 2 week not scheduled
(2) service: single implementation LArSoft core team June 2016 2 weeks delivered
(3) service: multiple implementations LArSoft core team June 2016 2 weeks delivered
templates LArSoft (and art?) team not scheduled

Code examples

Copying existing code is a standard practice for LArSoft developers, which has fed diffusion and adoption of unwanted, non-optimal and dangerous patterns.
Authors should be provided with examples from where to grow their code. These examples should:
  • be of limited scope and clear use case: authors can easily identify which example they want, and don't have to trim too much code
  • moderately documented: the code must be understandable, but since comments are typically left untouched and get outdated, they should not be overwhelming in number
  • fully working
  • pointing to the relevant documentation, if any
  • fully tested: examples do get old quickly and we don't want broken examples
Examples will be collected in larexamples repository and a catalogue will be maintained in the LArSoft wiki to make them easy to find.
A incomplete list of examples to be created:
  • a new data product
  • a new service (factorization model included)
  • a new service (factorization model and experiment-specific included)

Code templates

Templates are counterparts of examples that are supposed to be used by an author to start new code.
Differences with examples:
  • they don't need to be complete and functional
  • they can have extensive inline documentation and internal placeholders (e.g. CLASSNAME)
Other features:
  • they are supposed to be managed and used via a script (like artmod or cetskelgen) replacing placeholders and patching code together
  • stick to the basic patterns; experience has shown templates are hard to maintain up to date
Possible themes:
  • algorithm + module template
  • service templates

Data access

source contributors delivery effort status
global event LArSoft team not scheduled 4 weeks
associations creation LArSoft (and art?) team TBD
associations query LArSoft (and art?) team not scheduled
associations chains LArSoft (and art?) team TBD

Complete event view

An event view is an object that can provide a collection of objects for any relevant physics class, with no need for the caller to specify where each collection comes from.
This is envisioned as a analysis support tool configured centrally by e.g., a physics group, where it is decided which reconstructed track collection to use, which calorimetry, etc.
The object should be configured by FHiCL language.

Association utilities

The focus is on three aspects of use of associations: creation, query and chain query.

Creation of associations with data products
LArSoft CreateAssns() functions have become quite hard to use and often they are adding complication to user code rather than simplifying it. A common creation pattern is for a module to produce:
  • a main data product
  • ancillary data products
  • associations of the main data product (and ancillary ones) with its input data
  • associations of the main data product with the ancillary ones

If this pattern is uniform and repeated enough, supporting utilities should be written to make it straightforward1.

1 One such attempt for the specific use case of hit creation is recob::HitCollectionCreator (lardata/lardata/RecoBaseArt/HitCreator.h), which might be defined "moderately successful" in that I received a single unsolicited fairly positive statement and no negative statement about its usefulness.

Access to associated objects

A common usage pattern is to have an object (as opposed to an index) and to look for its associated objects.
This might be made simpler with a proper query object.

Access to indirectly associated objects

Under some assumptions, the query of objects only indirectly associated should be made easy (e.g. tracks -> ... -> hits).

Run-time interface

The user needs to know that an error message on the output is something to be fixed, and the same for a warning.
Module output to console needs to be cleaned and made readable.

source contributors delivery effort status
clean common module output LArSoft team not scheduled
generation (GENIEGen, CRY, CorsikaGen, SingleGen) not scheduled
simulation (LArG4) not scheduled
hit finding (GausHitFinder) not scheduled
cluster finding (fuzzyCluster, ...) not scheduled
track finding not scheduled
shower finding not scheduled
calorimetry not scheduled


source contributors delivery effort status
build machines not scheduled left to the experiments
VNC for event display request to CD

Machine devoted to code building

DUNE seems to have benefited from having a machine exclusively devoted to, and optimized for, software building.
All the experiments may be interested in having such a machine.
But we leave to each experiment the decision to request one.

VNC for event displaying from GPVMs

Remote event display with the X11 protocol is extremely demanding of the network resources.
Other protocols, like VNC, may be much better suited for slowly changing display applications like this one.

The first step should be for the GPVMs to enable the ability to host a VNC server.

Further ideas scoped out of "phase 1" usability project

Visual FHiCL aids:
  • editor:
    • scan available module and service configurations
    • visually assemble a workflow and services
    • visualize existing configuration files
    • clone and change existing configuration blocks or amend them
    • module and service configuration by form
      [?] given that algorithm configuration is mostly free-form, is this worth?
      [?] should we decorate algorithm configurations and develop a "protocol"?
  • viewer (a less ambitious target than an editor)
  • easy way to get standard reconstruction vs. truth comparisons

Event display.

_Last update: April 3rd, 2016._
_For questions or requests, please contact Gianluca Petrillo ._