# Shared recipe

Calling a method the best classifier is meaningless without a frozen bake-off
recipe. ARCADE’s headline claim is fairness: the same traces, the same
preprocessing, the same splits, the same metrics, and the same report shape
for every method in a given run.

## What is frozen

| Ingredient | Where it lives | Why it matters |
|------------|----------------|----------------|
| Trace file and keys | ``data.path``, ``data.hdf5_keys`` | Everyone sees the same shots |
| Demodulation, boxcar, truncate | ``data.demodulation``, ``data.preprocessing`` | Changes the IQ geometry |
| Label packing | ``data.label_format``, ``data.qubit_bit_order`` | Bit-order bugs look like bad models |
| Train, validation, and test | ``data.split`` | Leakage across methods is silent |
| Filter bank | ``classifiers.filter_types`` | MF, RMF, and EMF must be shared unless a method opts out |
| Metrics and report | ``visualization`` settings | Comparable tables |

The public reference eight-method recipe is ``configs/paper_all_methods_benchmark.yaml``.
Dedicated ``configs/paper_*.yaml`` files may differ slightly when a paper needs
a different protocol. Those are paper recipes, not silent edits to the reference
benchmark.

## What is allowed to vary

Which names appear in ``classifiers.run``. Per-method option blocks such as
``fnn.config_file``. Optional stages such as ``optimization``, ``qec``, and
``hardware.run_synthesis``.

## Pitfalls checklist

<div class="arcade-pitfall">
<p>HERQULES zoo filters are typically <code>[MF, RMF]</code>. Claiming bit-exact paper
parity needs the paper YAML. Path-signature zoo configs may set
<code>time_augmentation: true</code> while the paper path is two-dimensional I and Q.
Treat Readout 2019 path-signature results as transfer under the zoo recipe.
The name <code>mlp</code> is the scikit-learn multilayer perceptron. It is not the
Lienhard-style <code>fnn</code>. The name <code>reservoir</code> is a deprecated alias of
<code>ngrc</code>. It is not a classical echo-state network.</p>
</div>

Changing the recipe between methods turns the leaderboard into marketing.
Keep knobs under ``data`` once. Swap only ``classifiers.run`` when you want a
fair comparison.