• Table of contents
• Developing With LArSoft
  • Quick links for Developing with LArSoft
  • Access
  • Designing
    • LArSoft architecture and design principles
    • LArSoft packages and repositories
    • The art framework
    • gallery
    • External packages
    • Policy for including new packages in LArSoft
  • Writing code
    • Guidelines
    • How to...
    • Tips on updating your code after LArSoft release
    • Tools and techniques
      • Documenting and browsing code
      • Working with GitHub and contributing code via LArSoft pull requests
      • git and git flow
      • Profiling
      • Debugging
  • Building
    • Using the build system
    • Understanding CMakeLists.txt and product_deps files
    • mrb (multi-repository build) tool
    • ups
  • Testing
    • LArSoft Continuous Integration (CI) system
  • Submitting for next release

Developing With LArSoft¶

Quick links for Developing with LArSoft¶

• LArSoft repositories packages and dependencies
• Concepts in LArSoft

Access¶

In order to submit changes to larsoft code, you need developer access to the redmine repositories. Please send email to larsoft-team@fnal.gov. Please let us know who you are and your institutional association.

Designing¶

To design LArSoft code, it's important to understand the core LArSoft suite and all the components used by it. Reference the items below when designing new software.

LArSoft architecture and design principles¶

• Latest architecture document as PDF download
• Design principles on larsoft.org

LArSoft packages and repositories¶

• LArSoft repositories, packages and dependencies
• Geometry Package
• LArSoft art-independent code and repositories

The art framework¶

• art documentation on WordPress for general information
• art documentation in Redmine for code specific information
• art workbook for examples and tutorials
• Using art in LArSoft

gallery¶

gallery provides lightweight access to event data in art/ROOT files outside the art event processing framework executable. It is not an alternative framework; rather, it provides a library that can be used to write programs that need to read (but not write) art/ROOT files. Information is available at: http://art.fnal.gov/gallery/

External packages¶

These are package written and maintained by the general physics and computing communities for

Package	Namespace	Short description	Location of headers
C++	std::	Extensions to base C++ that are part of the standard language
ROOT	See below	Data-analysis tools	$ROOT_INC
CLHEP	CLHEP::	Class Library for High-Energy Physics	$CLHEP_INC/CLHEP
Geant4	See below	Detector simulations	$G4INCLUDE
GENIE	genie::	Neutrino Monte-Carlo Generator	$GENIE_INC/GENIE
boost	boost::	General programming tools for C++	$BOOST_INC/boost
Message Facility wiki documentation	mf::	Service for console messages	$MESSAGEFACILITY_INC
FHiCL Configuration	fhicl::	Configuration language and parsing tools	$FHICLCPP_INC
nutools and LArSoft	simb:: ...	Neutrino platform tools	$NUTOOLS_INC

ROOT and Geant4 do not use namespaces. In general, ROOT classes begin with "T" (e.g., TTree, TH1) while Geant4 classes begin with "G4" (e.g., G4Track, G4Step). Exception: Some of the newer ROOT sub-packages have namespaces (such as ROOT::Math::, ROOT::Fit::, ROOT::Minuit2::, Reflex::, TMVA::).

Some of these packages duplicate functionality; e.g., 4-vectors are implemented in both ROOT and CLHEP. Given a choice, use a package that's higher in the above tables over one that's lower; e.g., choose ROOT classes over their CLHEP equivalents.

Policy for including new packages in LArSoft¶

LArSoft's policy for including new external software packages in the LArSoft distribution:

• An experiment makes an official request via redmine.
• LArSoft verifies that it has permission to use the tool for research.
• LArSoft verifies that the package will be be used by more than one experiment. Note: if only one experiment intends to use the package, the SciSoft team can help, but the end product would reside in the experiment’s code, not in LArSoft.
• LArSoft has to be able to build the tool such that it has binary compatibility with other products which will be used at the same time. This means that any dependencies (e.g., python) must be the same as those used by the matching LArSoft distribution. In addition, if the product contains C++ or Fortran code, the product must be buildable with the same compiler used by the matching LArSoft release.
• If the package is built into LArSoft code, it must not have a license that affects the license of the LArSoft code. We must be able to distribute our LArSoft code without having to add their license to our code or change the way we distribute LArSoft code with it in there. For a package that isn’t linked into any part of the main LArSoft distribution, such as an analysis tool, LArSoft still needs to have permission to use the package for research, but isn’t worried about the licensing affecting LArSoft code.

Writing code¶

Whether you are writing new code or modifying existing code, please follow the guidelines listed below. There are also development tools and techniques available that can make coding easier.

Guidelines¶

1. Coding guidelines
2. Code documentation requirements and guidelines
3. Process for contributing code to LArSoft
4. Guidelines on writing (and using) services in LArSoft (in general)
5. Guidelines on writing (and using) algorithms in LArSoft (not specific to any algorithm)
6. Guidelines on using the geometry
7. Error handling policy
8. Examples!
9. some C++ suggestions
10. Using git repositories

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How to...¶

• ... create and use associations
• ... use the new ROOT vectors and linear algebra classes in the code (GenVector, SMatrix)

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Tips on updating your code after LArSoft release¶

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Tools and techniques¶

Documenting and browsing code¶

• LArSoft Doxygen - comments in the code are incorporated into documentation using the Doxygen tool.
• LXR Cross Referencer - general purpose source code indexer and cross-referencer that provides web-based browsing of source code with links to the definition and usage of any identifier. Supports multiple languages. Includes LArSoft code. Note, pages may take several seconds to load.

Working with GitHub and contributing code via LArSoft pull requests¶

Start by reviewing the information on the overview page for using LArSoft with GitHub. Contact your experiment offline management to identify acting Level 2 managers. Send any comments to scisoft-team@fnal.gov, or via Redmine issues.

git and git flow¶

• git guidelines
• git flow quick start
• Git Tips and Tricks
  (for the purposes of LArSoft development, please please ignore anything other than how to use various git commands to do specific tasks - and especially ignore the workflow advice)

Profiling¶

• memory profiling tools
• time profiling tools
• profiling utilities

Debugging¶

• Debugging LArSoft with Allinea
• Debugging LArSoft with RogueWave TotalView. (TotalView is no longer being paid for. Please use Allinea above instead.)
• Debugging with gdb

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Building¶

Using the build system¶

• Look for experiment specific guides to using and developing LArSoft code
• Choose the correct release from the List of LArSoft Releases and Release Notes.
• What to do when there is a new release (a.k.a. update LArSoft version)

To get write access to the repositories, speak to the offline coordinator for your experiment. If you have a question, send email to larsoft-team@fnal.gov.

Understanding CMakeLists.txt and product_deps files¶

• Cetbuildtools cmake modules: such as cet_make and cet_add_compiler_flags. Used in CMakeLists.txt files throughout LArSoft
• Art cmake modules: such as art_make and simple_plugin. Used in CMakeLists.txt files throughout LArSoft
• Defining products in the CET build environment: explains the product_deps file
• Adding Product Dependencies: how to edit the product_deps and CMakeLists.txt files to add dependencies
• Various helpful tips for coding in the CET C++ environment: things you hope you never need to know
• Building your own code with cmake: pointer to a really simple example
• Using find_global_symbol.sh to find unresolved symbols: automatic library search for symbols

mrb (multi-repository build) tool¶

• mrb user guide
• mrb reference guide
• Documentation for buildtool
  • mrb calls buildtool (from the cetbuildtools product) to perform the build.

ups¶

• Getting Started with UPS and About UPS
• About qualifiers: the things after "-q" in setup <prod> <ver> -q <qual>
• More Relocatable UPS Documentation

Testing¶

High-level description of testing is available at larsoft.org

LArSoft Continuous Integration (CI) system¶

• High-level description of CI
• CI results display page
• LAr-Continuous-Integration subproject wiki

Submitting for next release¶

After designing, coding, building and testing a piece of software, submit it to the LArSoft development branch so it is included in a new release.

• Getting new code into a LArSoft release (Procedures and policies for making changes to LArSoft releases)

Also look at Process for contributing code to LArSoft.