Complete 3-D Cross-n FOURIN Spectral Coupling
You are given a reduced source snapshot from a TERPSICHORE-style ideal MHD stability workflow.
The current implementation handles simpler spectral settings, but the included 3-D plasma-only reproduction exposes an incomplete capability: cross-n spectral coupling is not consistently preserved through the coefficient and downstream matrix/energy path.
Inspect the source and run:
python reproduce.py
The reproduction writes the candidate workflow's raw observations under
outputs/. The command returns nonzero if those observations are empty,
incomplete, or non-finite; it does not apply verifier-only capability
thresholds.
Your task is to complete the implementation so that a genuinely
three-dimensional mode set with multiple toroidal n groups is handled
consistently.
The intended capability chain is:
mode table -> trigonometric lookup -> branch metadata reduction -> FOURIN coefficients -> matrix assembly -> energy accounting
Do not hard-code:
- the included case;
- a fixed list of expected numbers;
- a fixed mode table;
- a single coefficient or matrix block.
Do not bypass the coefficient path by writing directly into matrix outputs. The implementation should support the general 3-D spectral-coupling workflow represented by the supplied task.
Internet access is not available during evaluation.