Spring 2026 Lecture 25 focuses on message passing, aggregation, node representations, and permutation symmetry. This guide follows the official slides and recording and adds a small self-check that does not depend on the enrolled-course grader.
Spring 2026 Lecture 26 focuses on states, actions, rewards, returns, values, and policy learning. This guide follows the official slides and recording and adds a small self-check that does not depend on the enrolled-course grader.
Spring 2026 Lecture 27 focuses on associative memory, energy functions, fixed points, and pattern retrieval. This guide follows the official slides and recording and adds a small self-check that does not depend on the enrolled-course grader.
Spring 2026 Lecture 28 focuses on energy-based probability models (the Gibbs distribution and its normalizing constant Z), stochastic neurons, and how to train such probabilistic networks. This guide follows the official slides and recording and adds a small self-check that does not depend on the enrolled-course grader.
CMU 11-785 Spring 2026 publishes official slides and YouTube recordings for all 28 content lectures, plus extensive bootcamps and recitations. Its HW1–HW4 specifications, starters, and evaluation still depend on Autolab, Piazza, and Kaggle.
A Claude Code- or Codex-style TUI depends on long-lived sessions, typed transcripts, and approval at tool boundaries—not a screen full of color.
Cognee is a data-to-memory pipeline: a relational store preserves sources and provenance, a vector store finds semantically similar content, and a graph store represents entity relationships, exposed through remember, recall, improve, and forget.
Week 1 has no algorithms. The live introduction explains what the course teaches: which week covers each component of an LLM, which language algorithms outside LLMs are also taught, and why language is hard. PA0 sets up the Python and Jupyter environment the later assignments use.
Week 10 treats web pages and human relationships as graphs. Link analysis teaches anchor text and PageRank: the long-run probability that someone clicking links at random is on a page is that page's score. Social networks covers centrality, the clustering coefficient, small worlds and weak ties. The final live lecture returns to LLMs with preference alignment, interpretability and machine translation.
Week 2 teaches three things: cutting text into tokens with BPE, computing the edit distance between two strings with dynamic programming, and estimating the next word's probability with n-grams, evaluated by perplexity. Each can be done on paper, and this post works one example of each.
Week 3 teaches logistic regression: turn a document into a feature vector, pass the weighted sum through a sigmoid to get a probability, measure the error with cross-entropy, and fix the weights with gradient descent. This post works the slides' movie-review example through a prediction, a loss and one weight update, and explains why evaluation looks at precision and recall.
Week 4 teaches search: turn the query and the documents into vectors, weight them with tf-idf, rank by cosine similarity, speed it up with an inverted index, evaluate with precision, recall and MAP, and finally connect to dense retrieval and RAG. This post works the slides' four-document example in full.
Week 5 teaches embeddings: the meaning of a word can be represented by the words that tend to appear around it. It builds vectors from co-occurrence counts and compares them by cosine, then trains dense vectors of a few hundred dimensions with word2vec, and finally separates static vectors from ones that change with context. The same week's live lecture on computational social science has no public material.
Week 6 has two halves. The pre-recorded material teaches neural networks: how one unit computes, why hidden layers are needed, the softmax, classification and language modeling with word vectors, and backpropagation. The live lecture introduces large language models: what they are, the three architectures, why so many tasks can be recast as continuing text, how to sample, how pretraining works, and how a model becomes an assistant.
Week 7 opens up the Transformer: how attention lets each token draw on the tokens before it, what parts make up a block, and how the input and output ends are attached. PA6a has you write causal self-attention, train a small model and compute perplexity. The same week's live speech lecture introduces the speech recognition task and word error rate.
Week 8 continues with speech: how sound is produced, how a waveform becomes the log mel spectrum a model consumes, and how Whisper turns audio into text with an encoder-decoder and cross-attention. PA6b converts text to speech and back and analyzes what was lost. Lab 4 introduces the PA7 agent loop and teaches teams to collaborate with GitHub.
Week 9 teaches recommender systems: content-based recommendation looks at the features of items, while collaborative filtering looks only at the ratings matrix and estimates unrated items from similar users or similar items. PA7 writes item-item collaborative filtering as a function and hands it to an LLM agent that makes tool calls, then adds ticket booking, web search and memory.
Lecture 3 decomposes neural-network training into computation graphs, local derivatives, and the chain rule: the forward pass computes a result; backprop accumulates gradients from the output so every parameter knows how to move.
Lecture 11 divides evaluation into what to test, how to measure it, and when the result stops being trustworthy. Benchmarks saturate or leak, prompts change scores, and an LLM judge remains a biased model.
Lecture 9 compares prompting, pruning, LoRA, prompt tuning, and adapters. Each asks the same question: how many parameters must change, and how much task-specific state must be stored, to adapt a large pretrained model?