Remove obsolete research_projects directory

[behroozazarkhalili]

Analysis: examples/research_projects/

📁 Directory Structure

examples/research_projects/
├── README.md
├── layer_skip/ (Added March 2025 - PR #3111)
├── stack_llama/ (Added July 2023 - PR #509)
├── stack_llama_2/ (Added July 2023 - PR #509)
└── toxicity/ (Added July 2023 - PR #509)

🔍 Usage Analysis

Documentation References:

• ✅ docs/source/example_overview.md:77 - Links to research_projects
• ✅ docs/source/detoxifying_a_lm.md:11-12 - Links to toxicity scripts
• ✅ docs/source/peft_integration.md:10-12 - Links to stack_llama scripts

CI/CD Integration:

• ❌ NOT tested in .github/workflows/
• ❌ NOT referenced in Makefile
• ❌ NO automated validation

Obsolescence Evidence

1. Broken API Usage:

# examples/research_projects/stack_llama/scripts/rl_training.py:77-79
config = PPOConfig(
    steps=script_args.steps,           # ❌ Parameter removed
    model_name=script_args.model_name, # ❌ Parameter removed
    ...
)

Current PPOConfig: No longer accepts steps or model_name parameters (confirmed via inspection - 163 total params, neither exists)

2. Deprecated Imports:

from trl.core import LengthSampler  # All examples use this
from trl import PPOTrainer, PPOConfig, AutoModelForCausalLMWithValueHead

3. Ancient Code Patterns (Last meaningful update: July 2023):

• Stack-Llama: Original RLHF pipeline from 2023
• Toxicity: PPO detoxification from 2023
• Stack-Llama-2: Llama 2 variants from 2023
• Layer-Skip: Added March 2025 (only recent one)

📊 Maintenance Status

Project	Created	Last Updated	Functionality
stack_llama	July 2023	~2 years ago	❌ Broken API
stack_llama_2	July 2023	~2 years ago	❌ Broken API
toxicity	July 2023	~2 years ago	❌ Broken API
layer_skip	March 2025	Recent	⚠️ May work

Assessment

Reasons for removal:

1. Non-functional: 3/4 projects use obsolete TRL API
2. Unmaintained: No CI testing, no validation
3. Misleading: Documentation links to broken code
4. Against Library Vision: TRL moving beyond research-only focus
5. Better Alternatives: Modern examples exist in examples/scripts/

Changes

• Removed examples/research_projects/ directory (21 files, 2116 deletions)
• Updated docs/source/example_overview.md to remove reference
• Updated docs/source/detoxifying_a_lm.md to remove broken script links
• Updated docs/source/peft_integration.md to remove broken script links

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[qgallouedec]

cc @sergiopaniego, @burtenshaw, we are removing these two-and-a-half-year-old examples. I'll leave it up to you to decide whether it would be wise to provide an updated version somewhere, at some point.