matching-pmh 1.4.1

Matching Principle for ML: estimate deployment nuisance geometry (Sigma_task, D1-D7) and train any encoder with matched PMH on your representations

matching-pmh

Deployment geometry in. Matched robustness out.

Estimate Sigma_task (D1–D7) · train any encoder with matched PMH · falsify with controls

PyPI · GitHub · Walkthroughs · Theory · Quickstart

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matching-pmh implements the Matching Principle: make your encoder robust along the directions that actually shift between train and deploy—not every input direction that happens to correlate with labels.

Step	What you do	What the library does
1. Nuisance	Name what can change at deployment without changing the label (site, lighting, sensor, format, …).	Registry + suggest_nuisance / nuisance="auto" to pick an estimator family.
2. Geometry	Collect source/target (or augmentation) batches that expose that variation.	Estimate Σ_task — covariance of label-preserving deployment nuisance — via D1–D7 (shift, augment, sequence, style Gram, …).
3. Training	Keep your task loss; point a hook at representations h = φ_θ(x).	Add matched PMH: shrink Jacobian sensitivity along Σ_task (matched penalty), not isotropic VAT/CORAL-on-weights alone.

Your stack, your hook. ResNet / ViT (timm, torchvision), GNN mean-pool, Whisper-style encoders, causal LMs with LoRA, or frozen features + PMHMatcher / sklearn. Two phases (estimate once → train every step), one tensor h, no framework lock-in.

Theory: definitions, lemmas, and loss forms in docs/THEORY.md (LaTeX-friendly).

Not a paper reproduction kit — adapt your own pipeline.
Start here: Getting started → Choose your setup → Gallery

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30-second start

pip install matching-pmh
python examples/01_domain_shift_d4.py
pmh-train list-methods

from pmh import PMHMatcher, PMHTrainer, PMHConfig

# NumPy / sklearn frozen features
matcher = PMHMatcher(nuisance="domain_shift", rank=32).fit(x_source, x_target)

# PyTorch — estimate + train in one call
trainer = PMHTrainer(model, hook="backbone", nuisance="auto", pmh_config=PMHConfig.balanced())
trainer.fit(train_loader, source_batches=src_loader, target_batches=tgt_loader, epochs=20)

Getting started · Choose setup · Benchmarks & TDI · Troubleshooting · 18 walkthroughs

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Problem, object, repair, unification

Problem	ERM uses every input direction that predicts labels—including nuisances harmful at deployment (lighting, site, sensor noise, formatting, renameable identifiers, …).
Object	Sigma_task = covariance of label-preserving deployment nuisance n (under law Q_n).
Repair	Matched PMH shrinks encoder sensitivity along Sigma_task, not uniformly (isotropic PMH / generic VAT).
Unification	CORAL, domain Grams, augmentation stacks, metric-learning directions, adversarial subspaces, and style Grams are different estimators of the same Sigma_task (Lemma D1–D7).

Matched loss (schematic): L = L_task + lambda * Tr(J_phi^T J_phi Sigma') with range(Sigma') covering range(Sigma_task). Details: THEORY.md.

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How it fits your codebase

 Phase A (once)              Phase B (every step)
 ----------------              --------------------
 source/target data    ->      x, y from your loader
       |                            |
 encoder (eval)        ->      encoder (train) -> h
       |                            |
 estimate D1-D7        ->      L_task(h, y) + PMHLoss(h, Sigma_hat)
       |
 artifact.pt

You keep	Library adds
Model, optimizer, task loss	SigmaTaskConfig, estimate_from_config
Data loaders	collect_features (optional)
Training loop / Trainer	PMHLoss.capped_total or PMHTrainer

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Walkthroughs (18 templates)

#	Guide	Run
1	PyTorch + D4	examples/01_domain_shift_d4.py
2	ResNet + D4	examples/12_resnet_hook_d4.py
3	Office-31 + sklearn	examples/06_office31_sklearn.py
4	Multi-layer CNN	examples/07_vision_multilayer.py
5	Compositional D5	examples/13_compositional_train_d5.py
6	LLM style D7	examples/08_hf_style_d7.py
7	HF Trainer + DPO	examples/11_dpo_lora_style_pmh.py
8	Falsification controls	examples/04_falsification_controls.py
9	CLI JSON jobs	pmh-train estimate --config ...
10	Lightning	examples/09_lightning_module.py
11	Temporal D6	API in guide
12	ViT / CLS + D4	examples/14_vit_cls_d4.py
13	Speech encoder + D4	examples/15_speech_encoder_d4.py
14	QM9 / molecules D5	examples/16_qm9_molecule_d5.py
15	Code / tokens D5	examples/17_code_tokens_d5.py
16	Augmentations D3	examples/18_augmentation_d3.py
17	Compare arms on your pipeline	examples/20_compare_training_arms.py
18	PMHTrainer quickstart	examples/01_domain_shift_d4.py

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Estimators at a glance (D1–D7)

Deployment story	Method	SigmaTaskConfig
Different site / camera / corpus; P(y given x) stable	D4	SigmaTaskConfig.for_domain(rank=32)
Low-rank shift; labels on both domains	D1	SigmaTaskConfig.for_subspace(rank=32)
Unstructured sensor / acquisition noise	D2	SigmaTaskConfig.for_isotropic(dim, noise_level)
Known augmentation modes (color, blur, crop, …)	D3	SigmaTaskConfig.for_augmentation() + aug_deltas
Nuisance on specific coordinates (atoms, tokens)	D5	SigmaTaskConfig.for_compositional(indices)
Drift along time within a sequence	D6	SigmaTaskConfig.for_temporal()
LLM style / format; semantics fixed	D7	SigmaTaskConfig.for_alignment(rank=32)

pmh-train list-methods

Hybrid nuisances: estimate separate Sigma matrices and add separate PMHLoss terms.

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Install

pip install matching-pmh

Extra	Use case
pip install "matching-pmh[vision]"	ResNet / ViT examples
pip install "matching-pmh[hf]"	D7 style Gram (Transformers)
pip install "matching-pmh[hf-lora]"	LoRA + DPO example
pip install "matching-pmh[sklearn,vision]"	Office-31 pipeline
pip install "matching-pmh[lightning]"	Lightning callback
pip install "matching-pmh[all]"	Development + docs

From source:

git clone https://github.com/vishalstark512/matching-pmh.git
cd matching-pmh && pip install -e ".[dev]" && pytest -q

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Documentation

Document	Purpose
GETTING_STARTED.md	Main adoption guide (start here)
CHOOSE_YOUR_SETUP.md	Pick API by stack and data
TROUBLESHOOTING.md	Errors, preflight, hook dim
gallery/	Copy-paste: vision / tabular / NLP
hooks.md	ResNet, timm, HF hooks
ADAPT_YOUR_PIPELINE.md	Integration checklist
walkthroughs/	18 stack-specific tutorials
THEORY.md	Mathematics

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Citation

Cite the Grand Unification / Matching Principle manuscript. See CITATION.cff in the repository.

@software{matching_pmh,
  title  = {matching-pmh: Matched PMH training from estimated deployment nuisance geometry},
  author = {Rajput, Vishal},
  year   = {2026},
  url    = {https://github.com/vishalstark512/matching-pmh}
}

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Contributing

See CONTRIBUTING.md.

License

MIT — see LICENSE.