Fix test test_robot.example_robot_anymal_d_cuda_0

[Kenny-Vilella]

Description

Following the merge of #1295, the test test_robot.example_robot_anymal_d_cuda_0 seems to fail due to overflow.
This increase of nconmax should solve the issue.
Example of failure:
https://github.com/newton-physics/newton/actions/runs/20937863230/job/60164800649

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Summary by CodeRabbit

• Chores
  • Updated robot simulation example configuration parameters for improved contact handling accuracy.

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[coderabbitai]

📝 Walkthrough

Walkthrough

A configuration parameter in the ANYmal D robot example is increased from 35 to 45. The change modifies the maximum number of contacts (nconmax) in the MuJoCo solver configuration for the example simulation. No other logic or functionality is affected.

Changes

Cohort / File(s)	Change Summary
Configuration Parameter Adjustment newton/examples/robot/example_robot_anymal_d.py	Increased nconmax parameter in SolverMuJoCo invocation from 35 to 45

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

• Fixing overflow in FastAllegro benchmark #1231 — Addresses MuJoCo nconmax overflow issues by adjusting the same parameter from 35→40 in benchmarks, directly related to this example adjustment.

Suggested reviewers

• adenzler-nvidia
• shi-eric

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title references fixing a specific failing test, which directly aligns with the PR's objective to fix the test_robot.example_robot_anymal_d_cuda_0 test failure caused by an overflow.

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✨ Finishing touches

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[Kenny-Vilella]

For reference, I could not reproduce the failure locally.
Tried on my workstation and on Horde, but did not see the failure.
The failure seems to occur quite consistently on the main CI.
Hopefully, the increase will be enough but can not guarantee it.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

newton/examples/robot/example_robot_anymal_d.py (1)

83-92: LGTM! The increased nconmax addresses the overflow issue.

Increasing the maximum contact constraint capacity from 35 to 45 is a reasonable fix for the test failure caused by the overflow after #1295.

💡 Optional: Consider adding a brief comment for future maintainability

A short comment explaining the rationale could help future maintainers understand why this specific value was chosen:

             ls_iterations=50,
-            nconmax=45,
+            nconmax=45,  # Increased from 35 to handle contact overflow (see PR #1339)
             njmax=100,

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between f8ed713 and db8d043.

📒 Files selected for processing (1)

• newton/examples/robot/example_robot_anymal_d.py

🧰 Additional context used

🧠 Learnings (4)

📚 Learning: 2025-08-19T12:27:30.629Z

Learnt from: preist-nvidia
Repo: newton-physics/newton PR: 579
File: newton/examples/example_mujoco.py:350-354
Timestamp: 2025-08-19T12:27:30.629Z
Learning: In Newton examples, Example.use_mujoco is a high-level attribute that controls whether to use MuJoCo solver vs other solvers (like XPBD), while SolverMuJoCo.use_mujoco_cpu controls the backend within MuJoCo (CPU vs Warp). These are separate concepts serving different purposes - the PR rename only applies to the solver parameter, not the Example class attributes.

Applied to files:

• newton/examples/robot/example_robot_anymal_d.py

📚 Learning: 2025-08-19T12:27:30.629Z

Learnt from: preist-nvidia
Repo: newton-physics/newton PR: 579
File: newton/examples/example_mujoco.py:350-354
Timestamp: 2025-08-19T12:27:30.629Z
Learning: In Newton examples, there's a distinction between solver parameters and Example class attributes. The Example class can have its own use_mujoco attribute for controlling example-level behavior (like CUDA graphs, rendering logic), while the solver uses use_mujoco_cpu for backend selection. These serve different purposes and should not be conflated during API renames.

Applied to files:

• newton/examples/robot/example_robot_anymal_d.py

📚 Learning: 2025-12-12T08:45:43.428Z

Learnt from: nvtw
Repo: newton-physics/newton PR: 1221
File: newton/examples/example_sdf.py:277-287
Timestamp: 2025-12-12T08:45:43.428Z
Learning: In Newtown (Newton) example code, specifically files under newton/examples, computing contacts once per frame and reusing them across all substeps is an intentional design choice, not a bug. Reviewers should verify that contacts are computed before the substep loop and reused for every substep within the same frame. This pattern reduces redundant work and preserves frame-consistency; do not flag as a regression unless the behavior is changed for correctness or performance reasons.

Applied to files:

• newton/examples/robot/example_robot_anymal_d.py

📚 Learning: 2026-01-13T03:11:40.556Z

Learnt from: jumyungc
Repo: newton-physics/newton PR: 1333
File: newton/_src/sim/builder.py:0-0
Timestamp: 2026-01-13T03:11:40.556Z
Learning: Ensure all VBD damping semantics follow Rayleigh-style damping and are unitless. This convention, demonstrated in SolverVBD, should be applied consistently across all VBD-related constraints in the codebase. In newton/_src/sim/builder.py, validate that any damping terms use the same normalization and are treated as dimensionless; add comments and unit tests to enforce consistency across VBD components.

Applied to files:

• newton/examples/robot/example_robot_anymal_d.py

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