Parameter Bounds Verification¶

This page documents the canonical parameter bounds, defaults, and the dual prior system. It serves as a reference for verifying that the parameter registry and parameter space remain in sync.

Invariants¶

All 14 physics parameters and 2 scaling parameters have vary_default=True.
Units follow the Angstrom convention throughout: \(q\) in \(\text{\AA}^{-1}\), \(D_0\) in \(\text{\AA}^2/\text{s}^\alpha\), velocities in \(\text{\AA}/\text{s}\).

Key Parameter Defaults¶

Parameter	Default	Min	Max	Notes
`D0_ref`	1e4	0	1e6	`max_bound=1e6`
`D0_sample`	1e4	0	1e6	`max_bound=1e6`
`alpha_ref`	0.0	-2.0	2.0	Default is 0.0, not 1.0.
`alpha_sample`	0.0	-2.0	2.0	Default is 0.0, not 1.0.
`v0`	1e3	0	1e6	Prior: (1e3, 500).
`v_offset`	0.0	-100	100	Allows negative values.

Dual Prior System¶

Heterodyne maintains two parallel sources of prior information. Both must stay in sync when parameter defaults or priors are updated.

Source 1: Parameter Registry (heterodyne/config/parameter_registry.py)

The immutable MappingProxyType registry defines prior_mean and prior_std for each parameter. These values are consumed by:

cmc/priors.py:build_default_priors()
cmc/priors.py:build_log_space_priors()

Source 2: Parameter Space (heterodyne/optimization/parameter_space.py)

The _DEFAULT_PRIOR_SPECS dictionary defines per-parameter prior specifications consumed by _default_prior() during ParameterSpace initialization.

Verification Procedure¶

When modifying any parameter default, bound, or prior:

Update the value in parameter_registry.py.
Update the corresponding entry in _DEFAULT_PRIOR_SPECS in parameter_space.py.
Run the validation test suite:
```
uv run pytest -m validation -v
```
Confirm that build_default_priors() and build_log_space_priors() produce consistent prior distributions by inspecting the test output.

Common Pitfalls¶

Setting alpha_ref or alpha_sample default to 1.0 instead of 0.0.
Forgetting to update _DEFAULT_PRIOR_SPECS after changing the registry (or vice versa).
Using nanometer units instead of Angstroms (all values must be in \(\text{\AA}\)).