TRExFitter Interop

NextStat can import TRExFitter .config files and run the full pipeline — from ROOT ntuples or pre-built histograms to fits and reports — without TRExFitter or ROOT C++.

Import a TRExFitter Config

# Convert a TRExFitter config into a pyhf JSON workspace
nextstat import trex-config --config myanalysis.config --out workspace.json

# Specify base directory for relative File: paths
nextstat import trex-config --config myanalysis.config --base-dir /data/ntuples/

Build Histograms (NTUP Mode)

# Run the ntuple pipeline and produce workspace.json
nextstat build-hists --config myanalysis.config --out-dir results/

# This reads ROOT ntuples, applies selections/weights,
# fills histograms, and assembles a HistFactory workspace.

HIST Mode

For configs with ReadFrom: HIST, NextStat reads pre-built ROOT histograms directly instead of processing ntuples. Both modes (NTUP, HIST, and mixed NTUP+HIST) are supported.

Analysis Spec v0

The Analysis Spec is a declarative YAML format that orchestrates the full workflow: import → fit → scan → report. JSON Schema is provided for IDE autocomplete.

# Run a full analysis from a spec file
nextstat run analysis.yaml

# Dry run (validate without executing)
nextstat run analysis.yaml --dry-run

Example spec:

# analysis.yaml
inputs:
  mode: trex_config_yaml
  config: myanalysis.config
  base_dir: /data/ntuples/

steps:
  - action: import
  - action: fit
  - action: scan
    poi: mu_sig
    range: [0.0, 3.0]
    points: 30
  - action: report
    blind: true

TRExFitter Config Subset

The following TRExFitter config blocks are supported:

• Job — ReadFrom (NTUP/HIST), POI, Lumi, regions, MCweight
• Region — Variable, Selection, Binning, Type (SIGNAL/CONTROL/VALIDATION)
• Sample — NtupleFiles, HistoFiles, MCweight, Selection, modifiers
• Systematic — NormSys, HistoSys, WeightSys, TreeSys, OverallSys
• NormFactor — free normalization parameters

Visualization Parity (18 / 18 plot types)

NextStat now covers every TRExFitter output plot type via the ns-viz crate. All artifacts are JSON-serialisable Rust structs with Python matplotlib renderers.

See the Visualization page for code examples and Rust artifact details.