aipoc-lab
[AI GLOSSARY][LLM][BASICS]

Large Language Model (LLM)

Authorship and approval

[Written with AI] [Approved by a human]

Updated

28.10.2026

A Large Language Model (LLM) is an AI model trained on huge collections of text that predicts the next word based on previous text, then the next, and so on. Answers to questions, translations, summaries, and code writing all stem from this single ability. ChatGPT, Claude, and Gemini are applications built on LLMs.

42.4%

papers on LLMs (wk. 43)

0 PLN

lab work models

2017

Transformer, the beginning of LLMs

How does it work?

  1. Pre-training: the model reads trillions of tokens of text and learns to predict the next word. This is how it acquires language and world knowledge.
  2. Fine-tuning: the model learns to be a helpful assistant, including via human feedback (RLHF). This also leads to the tendency to agree, known as sycophancy.
  3. Response: the model receives your question and writes a response token by token, each time choosing the likely continuation.

Underneath almost every LLM is the Transformer architecture from the paper "Attention Is All You Need" (2017).

How does our lab do it?

  • Lab work relies on the free Gemini tier (Flash Lite model): source evaluation, writing, translations. Cost of lab work models: 0 PLN per month.
  • The website chat uses a paid model via OpenRouter with zero data retention (the provider does not store conversations). Free Gemini returned overload errors in about 3 out of 10 tries, and human chat must always respond.
  • We dropped local LLMs. Three models at once on our server (15 GB RAM, no GPU) pushed it into swap memory and everything slowed down. Locally we only compute vectors (embeddings), because a small model is enough for that.
  • The model writes, code checks. Numbers in reports are compared with data by a program, and publication is approved by a human.

Limitations

  • Hallucinations: the model can confidently state falsehoods.
  • Sycophancy: the model tends to agree with the user.
  • Training cutoff knowledge: without search (RAG), the model does not know what happened later.
  • Context window: the model sees only a limited amount of text at once.

Related terms

Attention Is All You Need · Tokens and Context Window · AI Hallucinations · AI Sycophancy · RAG

Questions and answers

How does an LLM differ from ChatGPT?

An LLM is a model. ChatGPT is an application that uses OpenAI models and adds an interface, conversation memory, and tools to them.

Does an LLM understand text?

Certainly not like a human. It predicts text based on patterns. This turns out surprisingly well, but that is where hallucinations come from.

Can you run an LLM locally?

Yes, smaller models run on a regular computer, but slower and weaker than cloud models. Without a GPU, you quickly run out of memory.

Sources

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