‍Large Language Model: The Basic Process and Methods 101

‍Large Language Model: The Basic Process and Methods 101‍

Large Language Models (LLMs) are artificial intelligence algorithms that use deep learning and massive data sets to comprehend, generate, and anticipate human language. LLMs are also known as foundation models because they can be used for various natural language processing (NLP) and natural language generation (NLG) tasks, such as text summarization, translation, question answering, content creation, and more.

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LLMs have become increasingly popular and accessible in recent years, thanks to the advances in computing power and data availability. Many LLMs are open-source and can be accessed through platforms such as Hugging Face, GitHub, and LLM APIs. According to a report by OpenAI, the number of parameters in LLMs has increased by more than 10,000 times from 2017 to 2021, reaching up to trillions of parameters. The number of users of LLMs has also grown rapidly, reaching millions of monthly active users across various applications

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In this article, we will explain how LLM computational power is provided and what types of LLMs are used today.

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Data Collection

Data collection is the first step in providing LLM computational power. Data collection involves gathering a large amount of text data from various sources, such as articles, books, Wikipedia entries, and internet-based resources. This data is used to help the LLMs learn the complexity and linkages of language.

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The quality and quantity of the data collection affect the performance and accuracy of the LLMs. The data should be diverse, representative, and relevant to the desired task or domain. The data should also be cleaned and pre-processed to remove noise, duplicates, errors, and biases.

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Data source: Collecting a substantial amount of natural language corpus from various sources is crucial for creating a proficient LLM. LLMs currently in existence primarily use a combination of various public textual datasets as their pre-training corpus. The pre-training data used can be classified into two main types: general data and specialized data

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• General data: This type of data consists of text from various domains and genres, such as web pages, books, conversations, etc. General data is used to improve the language modeling and generalization skills of the LLMs. For example, GPT-3 uses a large corpus of web pages called Common Crawl as its main source of general data

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• Specialized data: This category of data contains text from a specific domain or task, such as medical records, legal documents, news articles, etc. Specialized data is used to enhance the domain knowledge and task performance of the LLMs. For example, BioBERT uses biomedical texts from PubMed and PMC as its source of specialized data

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Data preprocessing: Preprocessing the data involves transforming the raw text into a suitable format for the LLMs. This can include various steps, such as tokenization, normalization, segmentation, labeling, etc

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• Tokenization: The process involves splitting the text into smaller units called tokens, which can be words, subwords, characters, etc. Tokenization helps to reduce the vocabulary size and handle rare or unknown words. For example, BERT uses WordPiece tokenization to split words into subwords based on their frequency.

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• Normalization: The step takes standardizing the text by removing or replacing unwanted elements, such as punctuation, capitalization, spelling errors, etc. Normalization helps to reduce the variability and noise in the text. For example, T5 uses lowercase and punctuation removal as part of its normalization step.

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• Segmentation: This is the process of dividing the text into smaller chunks or segments based on some criteria, such as sentence boundaries, paragraph breaks, document length, etc. Segmentation helps to organize the text and facilitate its processing by the LLMs. For example, GPT-3 uses sliding window segmentation to split long documents into fixed-length segments with some overlap.  

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• Labeling:  Labeling is assigning labels or tags to the text based on some annotation scheme or task specification. Labeling helps to provide supervision and guidance for the LLMs to learn the desired output or objective. For example, BLOOM uses natural language prompts as labels to indicate the task and format for each input

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Model Training

Model training involves using deep learning techniques, such as transformers, to process text data and learn the patterns and probabilities of language. The models are trained on massive server farms or supercomputers with enough computing power to handle billions or trillions of parameters.

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The goal of model training is to create a general-purpose LLM that can perform a wide range of NLP and NLG tasks. The model training can take days or weeks depending on the size and complexity of the model and the data.

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• Pre-training and fine-tuning: Training of an LLM consists of two parts: pre-training and fine-tuning. Pre-training is part of training that enables the model to learn the general rules and dependencies within a language, which takes a significant amount of data, computational power, and time to complete. Fine-tuning is part of training that adapts the pre-trained model to a specific task or domain, which takes a smaller amount of data, computational power, and time to complete. For example, BERT is pre-trained on a large corpus of general text using two objectives: masked language modeling and next-sentence prediction. Then, it is fine-tuned on various downstream tasks, such as question answering, sentiment analysis, etc.

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•  Model architecture: Choosing or designing the right neural network architecture for the LLM is crucial for its performance and efficiency. The architecture determines how the model processes the input text and generates the output text. It also affects the number of parameters, memory usage, and inference speed of the model. One of the most popular architectures for LLMs is transformers, which use attention mechanisms to capture long-range dependencies and context in the text. Transformers have been used to build state-of-the-art LLMs such as GPT-3, BERT, T5, etc.

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• Optimization techniques: Optimizing the LLM during training involves adjusting the parameters to minimize a loss function that measures how well the model predicts the output text compared to the ground truth text. There are various optimization techniques that can help speed up the convergence and improve the accuracy of the LLM. For example, gradient descent is a basic algorithm that updates the parameters based on the gradients of the loss function. Adam is an advanced algorithm that adapts the learning rate based on the history of gradients. DeepSpeed is a library that provides various optimization techniques for LLMs such as ZeRO (Zero Redundancy Optimizer), which reduces memory usage by partitioning model states across multiple devices.

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• Evaluation metrics: Evaluating the LLM during and after training involves measuring its performance on various tasks and domains. There are different evaluation metrics that can be used depending on the type and goal of the task. For example, perplexity is a common metric for language modeling that measures how well the model predicts the next word in a sequence. BLEU is a common metric for machine translation that measures how similar the model-generated translation is to a human-generated reference translation. ROUGE is a common metric for text summarization that measures how much overlap there is between the model-generated summary and a human-generated reference summary.

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Model Fine-tuning

Model fine-tuning involves further customizing the general-purpose LLM for specific tasks or domains by fine-tuning it on smaller data sets that are relevant to the desired application. For example, an LLM can be fine-tuned on medical data to perform tasks such as diagnosis or prescription.

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The goal of model fine-tuning is to improve the accuracy and relevance of the LLM outputs for the specific task or domain. The model fine-tuning can take hours or days depending on the size and complexity of the model and the data.

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• Task definition: Defining the task or domain that you want the LLM to perform or specialize in is the first step of model fine-tuning. The task definition should specify the input and output format, the evaluation metrics, and the desired behavior of the LLM. For example, if you want to fine-tune an LLM for text summarization, you should define how long the summary should be, how to measure its quality, and what kind of tone and style you want it to use.

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• Data collection: Collecting a suitable data set for the task or domain is the second step of model fine-tuning. The data set should consist of pairs of input and output texts that represent examples of the task or domain. The data set should be large enough to cover the diversity and complexity of the task or domain, but not too large to cause overfitting or inefficiency. The data set should also be clean and consistent, without noise, errors, or biases.

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•  Model selection: Selecting a suitable pre-trained LLM for the task or domain is the third step of model fine-tuning. The pre-trained LLM should have a compatible architecture and vocabulary with the task or domain. It should also have a high performance and generalization ability on a variety of language-related tasks. For example, if you want to fine-tune an LLM for text summarization, you can choose T5, which is a transformer-based LLM that has been pre-trained on a large corpus of text using a text-to-text format.

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• Training procedure: Training the selected LLM on the collected data set for the task or domain is the fourth step of model fine-tuning. The training procedure involves adjusting the parameters of the LLM to minimize a loss function that measures how well the LLM predicts the output text given the input text. The training procedure should use appropriate hyperparameters, such as learning rate, batch size, number of epochs, etc., to optimize the speed and quality of the fine-tuning process. The training procedure should also use various techniques to prevent overfitting or underfitting, such as regularization, dropout, early stopping, etc.

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• Evaluation and deployment: Evaluating and deploying the fine-tuned LLM for the task or domain is the final step of model fine-tuning. The evaluation involves measuring the performance of the LLM on a held-out test set that consists of unseen input and output texts that represent examples of the task or domain. The evaluation should use appropriate metrics that reflect the quality and relevance of the LLM outputs for the task or domain. For example, if you want to evaluate an LLM for text summarization, you can use ROUGE, which measures how much overlap there is between the LLM-generated summary and a human-generated reference summary. The deployment involves making the fine-tuned LLM available for use in a production environment, such as a web service, an application, or a device.

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Model Deployment

Model deployment involves deploying the fine-tuned LLM on various platforms, such as cloud services, APIs, or applications, to provide computational power for natural language processing and generation tasks. For example, an LLM can be deployed on a chatbot service to provide conversational responses to users.

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The goal of model deployment is to make the LLM accessible and useful for various users and purposes. The model deployment can involve challenges such as scalability, security, privacy, ethics, and regulation.

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• Platform selection: Selecting a suitable platform for hosting the LLM is the first step of model deployment. The platform should provide enough computing power, memory, and bandwidth to handle the LLM inference requests. The platform should also support the desired interface and format for interacting with the LLM. For example, if you want to deploy an LLM on a cloud service, you can use Amazon SageMaker, which provides various features such as model hosting, endpoint management, monitoring, etc.

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• Model packaging: Packaging the LLM into a deployable unit is the second step of model deployment. The model package should contain all the necessary files and dependencies for running the LLM inference. The model package should also be compatible with the chosen platform and follow its specifications and requirements. For example, if you want to package an LLM for Amazon SageMaker, you can use a Docker container that follows the SageMaker inference toolkit.

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• Model testing: Testing the LLM before deploying it to production is the third step of model deployment. The testing involves verifying the functionality and performance of the LLM on a sample of input and output texts that represent examples of the task or domain. The testing should also check for any errors or issues that might occur during the inference process. For example, if you want to test an LLM for text summarization, you can use a validation set that contains input texts and reference summaries.

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• Model monitoring: Monitoring the LLM after deploying it to production is the fourth step of model deployment. The monitoring involves collecting and analyzing various metrics and logs that reflect the behavior and quality of the LLM inference. The monitoring should also alert for any anomalies or problems that might affect the user experience or satisfaction. For example, if you want to monitor an LLM for chatbot service, you can use metrics such as response time, accuracy, sentiment, etc.

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•  Model updating: Updating the LLM based on feedback and improvement is the final step of model deployment. The updating involves re-training or fine-tuning the LLM on new or revised data sets that reflect changes in the task or domain. The updating should also incorporate new features or enhancements that improve the functionality or performance of the LLM inference. For example, if you want to update an LLM for text summarization, you can use new data sources or methods that improve the quality or diversity of the summaries.

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Large Language Models (LLMs) are artificial intelligence algorithms that use deep learning and massive data sets to comprehend, generate, and anticipate human language. LLMs are also known as foundation models because they can be used for various natural language processing (NLP) and natural language generation (NLG) tasks.

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LLM computational power is provided by four steps: data collection, model training, model fine-tuning, and model deployment. Each step involves challenges and opportunities for improving the performance and accuracy of the LLMs.

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LLMs have become increasingly popular and accessible in recent years, thanks to the advances in computing power and data availability. LLMs have the potential to revolutionize various fields and industries by providing natural language processing and generation capabilities

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There are many types of LLMs that are used today for different purposes and applications. Next article will explore these LLMs: OpenAI's GPT models, Google's LaMDA and PaLM models, Hugging Face's BLOOM and XLM-RoBERTa models, Nvidia's NeMO model, and XLNet model.

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Sources:

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AI Multiple. “Large Language Model Training: How It Works.” AI Multiple, 23 Aug. 2021, https://research.aimultiple.com/large-language-model-training/.

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Dettmers, Tim, et al. “QLoRA: Efficient Finetuning of Quantized LLMs.” arXiv.org, 23 May 2023, https://arxiv.org/abs/2305.14314.

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Labellerr. “Data Collection and Preprocessing for Large Language Models.” Labellerr Blog, 23 Aug. 2021, https://www.labellerr.com/blog/data-collection-and-preprocessing-for-large-language-models/

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Li, Qingwei, et al. “Deploy Large Language Models on AWS Inferentia2 Using Large Model Inference Containers.” AWS Machine Learning Blog, 10 Apr. 2023, https://aws.amazon.com/blogs/machine-learning/deploy-large-language-models-on-aws-inferentia2-using-large-model-inference-containers/.

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OpenAI Safety & Alignment. “Best Practices for Deploying Language Models.” OpenAI Blog, 2 June 2022, https://openai.com/blog/best-practices-for-deploying-language-models/.

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Replit Team. “Training Large Language Models on Replit.” Replit Blog, 23 Aug. 2021, https://blog.replit.com/llm-training.

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Rouse, Margaret. “What Are Large Language Models and How Are They Used in Generative AI?” Computerworld, 9 Sep. 2021, https://www.computerworld.com/article/3697649/what-are-large-language-models-and-how-are-they-used-in-generative-ai.html.

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Unreal Engine Documentation Team. “Low Level Memory Tracker.” Unreal Engine Documentation, https://docs.unrealengine.com/4.27/en-US/ProductionPipelines/DevelopmentSetup/Tools/LowLevelMemoryTracker/.

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von Werra, Leandro, et al. “Fine-Tuning 20B LLMs with RLHF on a 24GB Consumer GPU.” Hugging Face Blog, 9 Mar. 2023, https://huggingface.co/blog/trl-peft.

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Zellers, Rowan, et al. “Eight Things to Know about Large Language Models.” arXiv.org, 4 Apr. 2023, https://arxiv.org/abs/2304.00612.

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