Debugging ~6 min · ~24 min remaining

Diagnose selections

Identify empty components, overlaps, and residual selections before applying loads.

Bug hunt

Download 02_bug_hunt.mac. The file runs, but contains five logical defects:

A physical region defined by node IDs.
A component created after restoring all nodes.
A local system that continues to operate unintentionally.
A tolerance of the same order as the mesh size.
A partial selection of elements that propagates to the end.

For each defect, write: incorrect state → probable symptom → check that reveals it → minimum correction. It is not enough to just point to the line.

Quick check

A component exists but is empty. What does that indicate?

The selection rule did not capture the expected entities. The material is incorrect. The mesh cannot converge.

Professional incident

Incident M02: diagnose before editing

A selection leaks into a later operation.

Execution cycle

1 Run the broken script in a clean folder.
2 Preserve the original .out.
3 Write one causal hypothesis and make one change.
4 Compare evidence before and after.

Evidence to retain

Initial hypothesis Changed line or block Output proving the cause Reusable prevention rule

What evidence separates the root cause from a lucky edit?

Graduated hints

1 · Concept hint

Find the first broken contract.

2 · Command hint

Inspect state related to NSEL, CMSEL, and ALLSEL.

3 · Explained solution

Compare with the module deliverable and explain why the corrected state restores the contract.

Your reflection stays in this browser.

View complete module Download m02-kit.zip