Fix performance issues: remove duplicates, fix broken deprecation warnings, optimize loops

[Copilot]

Description

Identifies and fixes slow/inefficient code patterns across the codebase.

Fixes:

• Duplicate function definitions (quat_from_euler_xyz, save_json, postprocess_small_regions)
• Broken deprecation warnings calling non-existent omni.log.warn → proper warnings.warn()
• rigid_body_twist_transform using deprecated quat_rotate_inverse → faster quat_apply_inverse

Optimizations:

• _sqrt_positive_part: indexed assignment → vectorized torch.where
• select_grasp, _generate_cache, _load_cache, get_dis_arr: loop-based array filling → np.array() + list comprehension
• differential_solver.get_ik: removed unnecessary deepcopy(), computed torch.inverse() once instead of twice
• remove_overlap_mask: pre-compute areas as numpy array

Example fix:

# Before (broken)
omni.log.warn("deprecated...")  # omni not imported

# After
warnings.warn("deprecated...", DeprecationWarning, stacklevel=2)

Type of change

• Bug fix (non-breaking change which fixes an issue)

Screenshots

N/A

Checklist

• I have run the black . command to format the code base.
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Dependencies have been updated, if applicable.

Original prompt

Identify and suggest improvements to slow or inefficient code

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.