Troubleshooting

IC rejected at startup

Confirm that all header arrays have length seven and that the empty PartType6 group contains zero-length Coordinates, Velocities, ParticleIDs, and Masses. Run validate_music2_ic_suite.py before changing the simulation code.

Particle-ID errors

Use IDS_64BIT and rerun the exact global uniqueness check. Never renumber an accepted IC casually: IDs are also used to trace Lagrangian regions and match particles across time.

Collective gravity or domain-decomposition hang

Check the last successful sync point, newly spawned dust counts, timebin assignment, rank imbalance, memory pressure, and whether all ranks reached the same collective. Preserve the full log rather than only the final line.

Unexpected dust mass jump

Break the result down by SNII, AGB, and LRN source; inspect feedback tranche counts; verify that DustParticlesPerSNII is distributed across the complete event rather than applied independently eight times; then run the whole-box mass and element audit.

D/G or D/Z changes unexpectedly

Verify center, aperture, phase selection, and denominator before changing physics. D/Z using gas-phase metals differs from D/Z using gas+dust metals.

Slow execution

Count domain decompositions, FOF/SUBFIND calls, active feedback/dust diagnostics, and snapshot writes. Compare the actual particle population and timebin distribution rather than inferring cost only from nominal resolution.