CXCSCMU GroupWiki

LTI Babel Cluster

For onboarding students, please carefully read the instruction slides.

Organize your code

Create your own branch for development and regularly submit changes to your branch! Here are some development steps you may refer to:

1. For new features/experiments, it is highly recommended to create a new branch
2. After developing and thorough test, merge the new features to your branch
3. If you think these features can benefit everyone in the group, merge them into the main branch by pull request (peers should do code review and test)

Organize your results

Loss curve

If you train the model, the loss curve is vital in debugging, providing insights, and reproducing your results.

It is recommended to use wandb to show your loss curve:

"""
Wandb setup
"""
wandb_project = YOUR_PROJECT_NAME
# IMPORTANT! Record the most important hyperparameters here
wandb_run_name = MODEL_NAME-DATASET_NAME-BATCH_SIZE-LEARNING_RATE-YOUR_RUN_NAME
# Optional but highly recommended
hparams = YOUR_HYPER_PARAMS_DICT
out_dir = YOUR_WANDB_OUTPUT_DIR
# You may be asked to fill in the API key. Find it online
wandb.init(project=wandb_project, name=wandb_run_name, config=hparams, dir=out_dir)

"""
Wandb logging
"""
wandb.log({
           "step": train_step,
           "train/loss": train_loss,
           "val/loss": val_loss,
           "step time": step_time,
           "lr": lr,
         })

When you are training, you can keep track of the curve online and export the reports to share at the end of the training. For your reference, this is an example report.

Evaluation numbers

Create the folder named by your name/project name under the Google Drive CXCSCMU_Group and use Google Sheets to illustrate the numbers.

• Make sure the column/row name is clear to read about the details of the model you are actually evaluating

• • ❌ Pythia
  • ✅ Pythia-160M full-model fine-tuned with SST-2 for1 epoch, lr=1e-5, bs=8

• Group the model sets that can be compared fairly in the same format as the research paper

Codebases

Lightning-Pretrain

An LLM codebase built on Lit-GPT and Pytorch Lightning, which is especially useful for efficient pre-training LM from scratch.

What can it do:

• Pre-train state-of-the-art decoder-only models (Llama, Llama 2, Pythia, Vicuna, GPT-2, ...)
• Fine-tune using task-specific data
• Evaluation on Language Model Evaluation Harness

Pros:

• State-of-the-art distributed training strategies: DDP, FSDP, DeepSpeed
• Modern acceleration strategies: FlashAttention, Fused Adam, mixed precision
• Parameter-efficient fine-tune: Adapter, Adapter v2, LoRA, QLoRA, ...
• Large-scale evaluation datasets: almost cover every common task in NLP and keep updating
• Comparable training speed with huggingface but better flexibility
• Relatively easy to convert the model weights from/to huggingface: name mapping
• Detailed tutorials for each usage, and it is pretty easy to begin with

Cons:

• Does not support models in other structures such as T5, BERT
• Does not support as many training datasets as huggingface, you may need to define the dataset class or preprocess the dataset by yourself
• Still in development and requires everyone's effort to maintain it

OpenMatch V2.0

(Yu et al., 2022) Paper | Github | Docs

A Python-based library for conducting Neural Information Retrieval (Neu-IR) research experiments. This library contains both neural and traditional IR modules, making it easy to conduct baselines experiments for comparison.

What can it do:

• Template-based Data Processing. Convenient templates for processing of raw data -- no need to reformat data to conform to software's input.
• Efficient Data Accessing. Integrated with HF datasets which enables access to large dataset with minimal memory overhead.
• Sharded Search. Implements two-stage sharded search which bypasses the need to load whole datasets into a single memory.
• A sample of models that are supported: DPR, ANCE, T5, BERT, etc.

Requirements:

• Pytorch
• HuggingFace, Datasets
• Transformers
• Faiss

A working directory of OpenMatch V2.0 exists in `/data/group_data/cx_group/OpenMatch` on the Babel server.

Paper reading

Research assistants' default minimum of paper reading is five per week. For your reference, this is an example.

Paper spotlight meetings

Meeting 1 - October 6, 2023

Paper	#Votes
Large Language Models Are Not Zero-Shot Communicators	2
Towards Structured Sparsity in Transformers for Efficient Inference	3
2x Faster Language Model Pre-training via Masked Structural Growth	1
Efficient Streaming Language Models with Attention Sinks	1
RAVEN: In-Context Learning with Retrieval Augmented Encoder-Decoder Language Models	0
Chain-of-Verification Reduces Hallucination in Large Language Models	3
Pre-train on just structure: Understanding linguistic inductive biases using transfer learning	2
Symbolic Discovery of Optimization Algorithms	0
Distill-VQ: Learning Retrieval Oriented Vector Quantization By Distilling Knowledge from Dense Embeddings	3
A Neural Corpus Indexer for Document Retrieval	1
RankVicuna: Zero-Shot Listwise Document Reranking with Open-Source Large Language Models	1
RAIN: Your Language Models Can Align Themselves without Finetuning	0

Meeting 2 - November 3, 2023

Paper	#Votes
SELF-RAG: Learning to Retrieve, Generate and Critique through Self-reflection	4
Reflection-Tuning:Data Recycling Improves LLM Instruction-Tuning	2
Tree Prompting: Efficient Task Adaptation without Fine-Tuning	2
Rewarded soups: towards Pareto-optimal alignment by interpolating weights fine-tuned on diverse rewards	2
LongLoRA: Efficient Fine-tuning of Long-Context Large Language Models	2
Are Emergent Abilities of Large Language Models a Mirage?	2
FlashAttention: Fast and Memory-Efficient Exact Attention with IO-Awareness	2
Seeking Neural Nuggets: Knowledge Transfer in Large Language Models from a Parametric Perspective	1
Large Language Models are Versatile Decomposers: Decompose Evidence and Questions for Table-based Reasoning	1
Intrinsic Dimensionality Explains the Effectiveness of Language Model Fine-Tuning	1
CodeFusion: A Pre-trained Diffusion Model for Code Generation	0
Connecting Large Language Models with Evolutionary Algorithms Yields Powerful Prompt Optimizers	0
ChunkAttention: Efficient Attention on KV Cache with Chunking Sharing and Batching	0
Walking Down the Memory Maze: Beyond Context Limit through Interactive Reading	0

Meeting 3 - December 1, 2023

Paper	#Votes
Learning To Retrieve Prompts for In-Context Learning	3
Language Models are Super Mario: Absorbing Abilities from Homologous Models as a Free Lunch	2
In-Context Pretraining: Language Modeling Beyond Document Boundaries	2
System 2 Attention	2
Learning to Skip for Language Modeling	2
SPAE: Semantic Pyramid AutoEncoder for Multimodal Generation with Frozen LLMs	2
Growing a Brain with Sparsity-Inducing Generation for Continual Learning	2
Generalization through Memorization: Nearest Neighbor Language Models	2
PDFTriage: Question Answering over Long, Structured Documents	1
Simplifying Transformer Blocks	1
Navigating the Grey Area: How Expressions of Uncertainty and Overconfidence Affect Language Models	1
Large Language Models are Zero Shot Hypothesis Proposers	0
SparseViT: Revisiting Activation Sparsity for Efficient High-Resolution Vision Transformer	0
Beyond Memorization: Violating Privacy Via Inference with Large Language Models	0

Meeting 4 - February 2, 2024

Paper	#Votes
Tuning Language Models by Proxy	5
Learning to Tokenize for Generative Retrieval	4
Can AI Assistants Know What They Don’t Know?	3
Lost in the Middle: How Language Models Use Long Contexts	2
Distilling Semantic Concept Embeddings from Contrastively Fine-tuned Language Models	2
Datamodels: Predicting Predictions from Training Data	2
User Embedding Model for Personalized Language Prompting	1
Improving Passage Retrieval with Zero-Shot Question Generation	1
Text Representation Distillation via Information Bottleneck Principle	1
Self-Rewarding Language Models	0
Retrieval is Accurate Generation	0
Learning Query-aware Embedding Index for Improving E-commerce Dense Retrieval	0
How to Prune Your Language Model: Recovering Accuracy on the ``Sparsity May Cry'' Benchmark	0
Explaining and Improving Model Behavior with k Nearest Neighbor Representations	0

Building from Open Source

A formalization of process of building from open source repositories.

Incremental Validation

Conducting incremental validation of an open source repository is highly recommended, so we can be sure that all components are performing as expected.

• Evaluate performance of outputs
  • Evaluate quickly on published outputs and check if performance agrees with what they claim.
  • For example, a “output” refers to the predicted rank in a retrieval task on a dev set.
• Evaluate performance on published artefacts
  • For example, if trained embeddings are available, validate performance on that using a prediction step of the downloaded trained model.
  • Unlikely to be available due to large file sizes (see: inference step).
• Run inference (forward) pass
  • To obtain predictions on downstream task
  • Follow open-source instructions for this step.
  • Check if performance agrees with performance claims.
• Run training
  • Required if you are further fine-tuning the model (or parts thereof)  
  • Follow up with inference

Mitigation / Debugs when Validation Fails

Some reasons why code doesn't work, and possible solutions.

• Code is not written to open-source standards
  • Code may have worked for authors, but not generally usable
  • Sometimes fixes are easy – check in/out directories
• Code is from awhile ago
  • Check package versions that authors use, and replicate in venv if possible
  • If intending to fine-tune model for future use, you probably want to update the code -- see documentation on any breaking updates
• Missing components needed
  • Probably the authors also based of their project off someone else’s – can do some digging to see if the missing component is anywhere else on the internet
• Everything runs without error, but results are just not replicable 😡
  • Check data processing (lookout for corrupted / truncated files)
  • Check model parameters (especially optimization parameters)
  • Check that “default” parameters in args correspond to optimal values they report in the paper

Always a good idea to check github issues and see if you problem is a "known" problem, and if there are any workarounds.

Debugging Deep learning Experiments

A step by step guide on debugging deep learning experiments

Step by Step Guide

• Reduce as much external factors as possible and try to localize the error/issue. Factors to reduce include
  • Number of GPU used in training
  • Dataset size
  • Dataset complexity (toy dataset)
• Check both input and output of all functions within the experiment. Do not assume you know what a function is doing
• Prioritize rapid debugging
  • Reduce training steps
  • Log output more frequently
• Avoid starting from scratch, leverage open source implementation
• Write test cases.
• Avoid multi-processing until the issues is identify