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Debugging ~6 min · ~24 min remaining

Diagnose loads and constraints

Identify empty selections, incorrect distributions, and confused reference systems.

Bug hunting

Run 05_bug_hunt.mac. It does not contain a solver failure; it contains five logically incorrect implementations.

  1. fixed_nodes is created after all nodes are restored.
  2. The fixed support ends up applied to the entire model.
  3. NSEL,R tries to find the tip within a selection that no longer contains it.
  4. Full force is applied to each tip node.
  5. CSYS, DSYS, and RSYS are used as if they rotated the nodal system.

Professional incident

Incident M05: diagnose before editing

What you must demonstrate

The solved total load differs from the declared resultant.

Incident file

This is not your session template — it is a broken script for diagnosis practice.

Download 05_bug_hunt.mac

Steps

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

Your reflection stays in this browser.

Graduated hints

1 · Concept hint

Find the first broken contract.

2 · Command hint

Inspect state related to NSEL, *GET, F, and FSUM.

3 · Explained solution

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

After running the script, reviewing the .out, and saving evidence, answer:

Quick check

A nodal selection for loading is empty. What is the safe response?

View complete module Download m05-kit.zip