Phlex India workshop sandbox

Note

This is a workshop practice repository, not the official one. It was made for the DUNE Phlex workshop at IISc Bengaluru (October 2026). The example code is the official Framework-R-D/phlex-examples, included as a git submodule in phlex-examples/ at the phlex-v0.4 branch (commit c55bbfc). You can read and build it, but you can't push to it. See WORKSHOP.md for the rules for pushing here.

What's here

File	What it is
cmake-warmup/	A tiny C++ project to practise CMake on, before Phlex
phlex-examples/	The official examples (a submodule, read-only). Today we build the files below from it
my_add.cpp, my_geometry.cpp	"Experiment code": ordinary C++ that knows nothing about Phlex (SHARED libraries)
numbers_source.cpp, geometry_source.cpp	Providers: bring data into the job
add_and_verify.cpp	A transform (adds two numbers) and an observer (checks the answer)
subtract.py	A transform written in Python
test-cpp-workflow.jsonnet, test-py-workflow.jsonnet	Job configurations
contributions/	Where workshop participants add their own work

Get the code

Clone with --recurse-submodules, or phlex-examples/ will be empty:

git clone --recurse-submodules https://github.com/<you>/dune-tech-phlex-sandbox.git

If you already cloned without it, run git submodule update --init inside the repository.

Build

From the directory that contains this repository (the build directory sits next to it):

mkdir build-sandbox
cd build-sandbox
cmake ../dune-tech-phlex-sandbox
cmake --build . -j 4

Run

From the build directory:

export PHLEX_PLUGIN_PATH=${PWD}:${PHLEX_PLUGIN_PATH}
phlex -c ../dune-tech-phlex-sandbox/phlex-examples/test-cpp-workflow.jsonnet --stage examples

The end of the output should show:

Processed layers:

  job
   │
   └ spill: 10

For the Python algorithm:

export PYTHONPATH=$(realpath ../dune-tech-phlex-sandbox/phlex-examples):${PYTHONPATH}
phlex -c ../dune-tech-phlex-sandbox/phlex-examples/test-py-workflow.jsonnet --stage examples

--stage names the processing pass. Current Phlex releases require it.

Where to go next

Everything else in phlex-examples/ is worth reading: an unfold example and the GausHitFinder migration from LArSoft in four designs with tests. The official repository also has a branch for each Phlex release (phlex-v0.3, phlex-v0.4, …).

To work on it for real after the workshop, clone the official repository on the branch that matches your phlex --version:

git clone -b phlex-v0.4 https://github.com/Framework-R-D/phlex-examples.git