[AlexanderFengler]

Spine plan: https://github.com/lnccbrown/HSSMSpine/blob/main/plans/derive-aux-networks.md#pr-stack (step H2 of 8)
Depends on: main (H1, #1438, is merged)
Unblocks: CPNs on the Hub, which are promoted only once a release contains this; the pipeline's CPN hssm_missing_load gate

Closes #1324

Why

• A missing-RT row (rt == -999.0, no deadline) still has an observed choice, but the CPN was called with the parameters only. Every such row got the probability of one fixed choice, whichever choice the participant made.
• Which choice that was depended on how the network had been trained, a convention HSSM could not see or check.

What

• Breaking: the CPN input is now [θ…, choice] -> log P(choice | θ), the same layout the OPN already uses with the deadline ([θ…, deadline]). Both have input width n_params + 1.
• HSSM wires the CPN with params_only=False, like the OPN. assemble_callables splices in the response column for missing-RT rows and the deadline column for omission rows.
• An ONNX network of any other width is rejected when the model is built, with a message that links CPN input contract: pass the observed choice to the choice-probability network #1324. The check runs under hssm.track's missing-data role, so a tracked fit still records the CPN as its missing-data network.
• Missing-RT rows whose response is not in choices now raise a clear ValueError. The data validator used to skip these rows.
• tests/fixtures/ddm_cpn.onnx is regenerated at width 5 from the DDM LAN fixture with LANfactory's derive-aux. Its provenance is in tests/fixtures/ddm_cpn.provenance.json.
• The lapse term on these rows is unchanged from H1 (1 / n_choices).
• Docstrings (HSSM, HSSMBase, make_missing_data_callable, assemble_callables, make_jax_logp_funcs_from_callable) and docs/reference/models-and-likelihoods.md describe the contract. Changelog: 0.5.1 item 19, plus a "Breaking changes" note.

Migration (hand-trained CPNs only)

• A CPN trained on the old params-only input (width n_params) is rejected at build time. Retrain it on rows whose last column is the choice, [θ…, choice], labelled with P(choice | θ).
• No CPN was ever published on franklab/HSSM, so no Hub artifact breaks.
• Callables built by hand with assemble_callables(..., params_only=True) still work. They are called as f(None, *params).

Not in this PR

• Lapse choice component is not normalised on observed and choice-only rows #1323 (H3): the lapse choice factor on observed rows and for choice-only models.

Tests

• tests/test_cpn_choice_input.py (13 tests): the fixture against its provenance, the width error for a params-only CPN and a wrong-width OPN, invalid responses on missing rows, a user callable receiving the missing rows' response, and the missing-row log-likelihood against the lapse mixture of the CPN computed with onnxruntime.
• tests/test_missing_and_deadline.py: the CPN case runs again (JAX and PyTensor agree on value and gradient).
• tests/test_make_jax_single_trial_logp_from_networks.py: the input vector layout is pinned.
• tests/test_lapse_missing_rows.py and tests/integration/test_missing_data_mcmc.py: H1's closed-form CPN test and the missing-data MCMC grid run under the new contract.

uv run ruff check . && uv run ruff format --check .
uv run pytest tests/test_cpn_choice_input.py tests/test_missing_and_deadline.py \
  tests/test_lapse_missing_rows.py tests/test_make_jax_single_trial_logp_from_networks.py \
  tests/integration/test_missing_data_mcmc.py
uv run pytest tests/ -m "not slow"

🤖 Generated with Claude Code

Summary by CodeRabbit

• Behavior Changes
  • Missing-data choice-probability networks now receive the observed choice as their final input; omission-probability networks receive the deadline.
  • Parameter-only callables remain supported when configured for parameter-only inputs.
• Validation
  • Invalid responses on missing-response-time rows are rejected for choice-probability models.
  • ONNX networks with an incompatible input width are rejected during model construction. Older parameter-only choice-probability artifacts may no longer load.
• Documentation
  • Updated guidance describes the input layout for missing-data networks and callables.

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Walkthrough

Missing-data CPNs now receive the observed choice as their final input; OPNs continue to receive the deadline. HSSM checks static ONNX input widths during construction and validates missing-row responses when no deadline is used. Parameter-only callables remain supported with params_only=True.

Changes: Missing-Data Network Inputs

Layer / File(s)	Summary
Route data columns to missing-data networks src/hssm/distribution_utils/dist.py, src/hssm/distribution_utils/jax.py, src/hssm/distribution_utils/onnx.py, src/hssm/hssm.py, tests/distribution_utils/test_jax.py, tests/conftest.py, tests/fixtures/ddm_cpn.provenance.json, tests/integration/test_missing_data_mcmc.py, tests/test_lapse_missing_rows.py, tests/test_make_jax_single_trial_logp_from_networks.py, tests/test_missing_and_deadline.py, tests/test_cpn_choice_input.py	assemble_callables passes the response column to CPNs and the deadline column to OPNs when params_only=False. HSSM configures CPNs to use this input path. Tests cover CPN evaluation, gradients, and single-trial and vectorized calls.
Validate network widths and missing-row responses src/hssm/hssm.py, src/hssm/data_validator.py, docs/changelog.md, docs/reference/models-and-likelihoods.md, src/hssm/base.py, tests/test_cpn_choice_input.py	HSSM rejects CPN or OPN ONNX networks with a static input width other than n_params + 1. When missing data is enabled without a deadline, invalid responses on missing-RT rows raise a ValueError. Documentation describes the input contract and migration behavior.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant HSSM
  participant assemble_callables
  participant CPN
  HSSM->>assemble_callables: Send model parameters and missing-row data
  assemble_callables->>CPN: Send parameters followed by observed choice
  CPN-->>assemble_callables: Return choice log-probability
  assemble_callables-->>HSSM: Return missing-row log-probabilities

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Merge Risk: Minimal · previous review 90d92

Missing-row CPNs receive the observed choice. No material merge risk remains from the reviewed changes.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title "Pass the observed choice to the CPN as its last input (#1324)" matches the main change in the changeset. The raw summaries show the CPN input contract change: networks receive `[θ…, choice]…
Linked Issues check		Issue #1324 is directly linked and has coding requirements. The supplied PR evidence shows that HSSM uses params_only=False for CPNs, assemble_callables appends each missing-RT row's response, a…
Out of Scope Changes check		The supplied whole-PR summary ties the implementation, validation, ONNX fixture and provenance, documentation, changelog, and tests to issue #1324. The OPN width check shares the documented `n_params …
Docstring Coverage		Docstring coverage is 86.36% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentati…

Full details: Title check

Explanation

The title "Pass the observed choice to the CPN as its last input (#1324)" matches the main change in the changeset. The raw summaries show the CPN input contract change: networks receive [θ…, choice] as the final input, the width check, and the response validation on missing-RT rows. The linked objectives describe the same change, and the issue number is referenced. The title is concise, specific, and a single sentence.

Full details: Linked Issues check

Explanation

Issue #1324 is directly linked and has coding requirements. The supplied PR evidence shows that HSSM uses params_only=False for CPNs, assemble_callables appends each missing-RT row's response, and the validator rejects invalid missing-row responses with a reference to #1324. HSSM rejects fixed-width ONNX CPN and OPN inputs that are not n_params + 1, and the check runs under missing-data tracking. The DDM CPN fixture was regenerated at width 5. The CPN test case was re-enabled, and the reported tests cover response propagation, width validation, fixture behavior, lapse mixing, and gradients. The evidence also states that the 1 / n_choices lapse term is unchanged.

Full details: Out of Scope Changes check

Explanation

The supplied whole-PR summary ties the implementation, validation, ONNX fixture and provenance, documentation, changelog, and tests to issue #1324. The OPN width check shares the documented n_params + 1 contract and supports the common missing-data network path. The params_only=True callable support documents and preserves the migration compatibility stated in the PR. No unrelated change is demonstrated. Issue #1323 is explicitly excluded.

Full details: Docstring Coverage

Explanation

Docstring coverage is 86.36% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 22 functions across 13 files. (3 skipped: 3 unsupported.)

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Commits

Reviewing files that changed from the base of the PR and between cacdd1d and 90d922f.

Files selected for processing: 17

• docs/changelog.md
• docs/reference/models-and-likelihoods.md
• src/hssm/base.py
• src/hssm/data_validator.py
• src/hssm/distribution_utils/dist.py
• src/hssm/distribution_utils/jax.py
• src/hssm/distribution_utils/onnx.py
• src/hssm/hssm.py
• tests/conftest.py
• tests/distribution_utils/test_jax.py
• tests/fixtures/ddm_cpn.onnx
• tests/fixtures/ddm_cpn.provenance.json
• tests/integration/test_missing_data_mcmc.py
• tests/test_cpn_choice_input.py
• tests/test_lapse_missing_rows.py
• tests/test_make_jax_single_trial_logp_from_networks.py
• tests/test_missing_and_deadline.py

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