skim_for_RGD

A fast C++ HIPO skimmer for CLAS12 Run Group D. It reads pass1 reconstructed DST files and writes much smaller per-run skims containing only electron-triggered events with a reduced set of banks — the input for the downstream RG-D analyses (timelines, transparency, etc.).

For each run under /cache/clas12/rg-d/production/pass1/recon/<target>/dst/recon/, it keeps events where REC::Particle has a "good electron" (pid == 11, status < 0, -10 < chi2pid < 10), and for those events writes a whitelist of banks (RUN::config, RUN::scaler, REC::Event, REC::Particle, REC::Calorimeter, REC::ForwardTagger, REC::Scintillator, REC::Track, REC::CovMat, REC::Traj, REC::Cherenkov, RUN::rf) to skim_run_<run>.hipo under /volatile/clas12/ouillon/skim_pass1_RGD/<target>.

Build & run

C++ (meson/ninja); depends on the hipo4 library via a git-submodule meson subproject.

git submodule update --init      # fetch subprojects/hipo (first time)
meson setup build
ninja -C build
./build/skim_rgd                 # takes NO args — paths/target/threads are hardcoded in src/main.cpp

Input paths, the target (currently CuSn), the output dir, and the 40-thread count are all hardcoded in src/main.cpp — edit there to change targets.

Key files

• src/main.cpp — entry point; enumerates run folders per target and dispatches via multi_thread_reader(..., 40).
• src/skimer/Reader.cpp — the skim logic (electron filter + bank whitelist + HIPO writer).
• include/skimer/Reader.hpp — skimer::Reader functor (operator()(run)).
• include/thread_pool/{multi_thread.hpp,BS_thread_pool*.hpp} — vendored BS::thread_pool + the per-run parallel driver.
• meson.build — build definition; subproject('hipo') + dependency('hipo4').
• subprojects/hipo/ — HIPO library as a git submodule (build dependency, keep).

Notes

• Cleaned up (2026-07-20): removed build/ and the .cache/clangd index. Rebuild with the commands above.
• The meson project was renamed from the template default project_template to skim_rgd (the built executable name follows the project name).