`from_agents` parameter slice¶

AgentModelState::from_agents now gives AgentModel::init the model-owned parameter slice. A boids regression test protects custom-lane construction from using the composed engine parameter list.

State before¶

The parameter-index change on PR #35 made model parameter constants local to each model-owned descriptor list. AgentModelState::from_params_seeded already split the composed list before calling AgentModel::init. AgentModelState::from_agents still passed the full composed list to init. For boids, that made MAX_SPEED and MIN_SPEED resolve to separation and alignment when the callback only replaced positions.

What was done¶

Split the composed list before from_agents calls AgentModel::init.
Passed own to init and retained the field slice for field allocation.
Added a boids test that overrides only the initial position and asserts the initialized velocity uses the configured speed band.
Ran both affected library test suites and formatting checks.

Edited codebase structure¶

crates/
├── henad-compute/
│   └── src/
│       └── cpu/
│           └── agent_engine.rs           ~ split composed params before `from_agents` initialization
└── henad-models/
    └── src/
        └── boids/
            └── mod.rs                    ~ regression coverage for seeded velocities
docs/
└── agent-record/
    └── 20260816-09-from-agents-param-slice.md  + session hand-off

State after¶

Both agent-state constructors pass model-local parameters to AgentModel::init. from_agents callbacks can override a subset of initialized lanes without inheriting initialization values from the wrong composed-list offsets.

Verification completed with cargo test -p henad-models --lib, cargo test -p henad-compute --lib, cargo fmt --all -- --check, and git diff --check.

Issues found & future directions¶

The defect was found by the PR #35 review after the parameter-index migration. No further mismatched AgentModel::init call sites were found.

Manual notes (human)¶

Can confirm that this is a valid issue. Manually added a epsilon for float comparison.

from_agents parameter slice¶