CS124 Winter 2026 opens by mapping a ten-week path from tokenization and classification to retrieval, speech, networks, and LLMs, while PA0 establishes the Jupyter environment used throughout the quarter.
Week 10 models the Web with anchor text, PageRank, and centrality; post-training, multilinguality, and speech belong only to a public final-deck outline labeled 2025, not the 2026 live narration.
Week 2 builds three layers: a token vocabulary with BPE, sequence comparison with dynamic-programming edit distance, and probability approximation with n-grams; PA1 turns regex and BPE into executable work.
Week 3 connects text features, sigmoid probabilities, cross-entropy loss, and gradient descent, producing a classifier whose feature contributions remain inspectable.
Week 4 builds candidates with an inverted index, ranks them with tf-idf and cosine similarity, and then connects retrieved evidence to generation; PA3 exposes RAG's inspectable retrieval half.
Week 5's public materials support the distributional hypothesis, word embeddings, and cosine similarity; the paired Social NLP lecture is unrecorded and restricted, so concrete audit methods are labeled as author extensions.
Week 6 uses public neural-network slides for weighted sums, nonlinearities, loss, and backpropagation, then a public LLM/Transformer deck labeled 2025 for decoder-only architecture without treating it as the 2026 live transcript.
Week 7's public path is PA6a: implement causal self-attention, train a small Shakespeare Transformer, sample text, and compute perplexity; the live speech lecture remains an explicit source gap.
Week 8 sends text through TTS and back through STT, requiring error classification, formatting-loss analysis, and accent stress tests, while Lab 4 prepares Git collaboration for the team agent project.
Week 9 builds movie recommendations with item-item collaborative filtering, then packages recommendation, web search, databases, and memory as agent tools under API-budget and team constraints.
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?
Lecture 6 completes the Transformer picture with encoders, decoders, and cross-attention, then breaks the final project into formats, assessment, research topics, and data. A viable topic needs one explicit baseline and metric.
Winter 2026 Lecture 1 divides NLP into four eras: early exploration, symbolic systems, statistical machine learning, and deep/self-supervised learning. The point is not the dates but how each era redefined the language problem.
Lecture 15 is Been Kim's interpretability guest session, but the Winter 2026 site publishes no slides or agenda. This article does not invent lecture content; it maps the five official readings across concept discovery, agentic investigation, and new vocabulary.
Lecture 17 is Luke Zettlemoyer's multimodality guest session, but the site publishes no slides or agenda. Its official readings establish three routes: visual reasoning workspaces, early-fusion token models, and text autoregression with image diffusion.
The final lecture frames Open Questions in NLP 2026 as smart scaling: prolonged RL, Prismatic synthetic data, RL as pretraining, and open collaboration seek reasoning gains beyond adding parameters.
Lecture 8 explains how instruction tuning, preference data, and RLHF turn a pretrained model into an assistant, then derives DPO from winner–loser pairs. Every step converts human judgment into signal—and imports its biases.
Lecture 7 decomposes pretraining into scalable data, subword tokenization, three model objectives, and in-context learning. A general self-supervised objective yields reusable representations; downstream signals specify their use.
Lecture 10 moves from question answering and RAG into language agents, then decomposes them into reasoning and planning, memory, tools, data, and evaluation. An agent is an inspectable loop between a model and external state.
Lecture 12 shows that output policy is not a detail: greedy, beam, and sampling produce different text. It then moves from R1-Zero/R1 into PPO, GRPO, and DAPO, asking when longer reasoning actually helps.
Lecture 13 moves from inference efficiency to inference capability: speculative decoding drafts with a small model and verifies with a large one; on-policy distillation addresses drift; long context and test-time scaling spend inference resources.
Lecture 4 defines a language model as a next-word probability distribution, then uses an RNN to compress an arbitrarily long prefix. It also exposes recurrence's central cost: information and gradients travel one time step at a time.
Lecture 16 divides NLP's social impact into four questions: why models hallucinate, why AI-assisted creativity may homogenize output, how work is reorganized, and why value alignment cannot be reduced to one reward.
Lecture 18 is a John Schulman guest session. The official page gives only the title Tinker and LoRA Without Regret, date, and speaker—no slides, agenda, or readings—so this article records confirmed facts and unknowns only.
Lecture 14 moves from word, character/byte, and subword segmentation to BPE failures and cross-lingual fairness. A tokenizer determines sequence length, compute cost, and the units a model sees; it is not neutral preprocessing.
Lecture 5 moves from the long-range and sequential bottlenecks of RNNs to self-attention and the Transformer. It shortens information paths and enables parallel computation, at the price of quadratic attention and separately encoded position.
Lecture 2 moves from word2vec's prediction task, objective, and gradients to count-based vectors and evaluation. Meaning becomes a high-dimensional position learned from context, not a label retrieved from a dictionary.
SPINACH does not guess complete SPARQL in one shot. It searches entities and properties, inspects Wikidata entries and examples, executes small queries, and composes a final query under explicit action and stopping rules.
CHURRO represents full-page text, layout, and metadata in HDML, unifies multilingual historical data for a page-level VLM, and connects extraction to HistoryGenie for searchable, conversational archives.
The final lecture is not a complete LLM-training tutorial. It studies data efficiency under fixed data and abundant compute, revisiting epochs, batches, ensembles, self-training, and conditions for synthetic continued pretraining.
The [WikiChat paper](https://aclanthology.org/2023.findings-emnlp.157/) expands RAG into query formulation, retrieval, filtering, generation, claim extraction, renewed retrieval and verification, and removal of unsupported content—and evaluates retrieval separately from factuality.
Fall 2025 opens with computational thinking: reliability comes from decomposing retrieval, formal representation, verification, and generation into testable algorithms, not from one heroic prompt.
STORM uses perspective-guided questions, simulated interviews, and outlines to broaden research; Co-STORM keeps a person in the loop so discovering unknown questions and co-editing become part of the system.
SLIDERS induces a question-specific schema, applies semantic chunking and contextualized extraction, reconciles duplicate rows, and answers with SUQL instead of feeding every long document directly to one model.
ReactGenie annotates React components to expose data, actions, and views, parses composite voice commands into a DSL, and renders native graphical output against shared UI context.
The lecture parses patient records and trial criteria into SMT, retrieves candidates through a weaker propositional projection, and runs a solver on the reduced set. Reasoning is inspectable, but NL-to-SMT remains the main error boundary.
Automated qualitative coding defines event types and arguments in a codebook, then separates document classification, structured extraction, and entity linking. Constrained JSON fixes form, not expert judgment.
Reliable database agents map language to executable queries, resolve schemas and enumerated values, and evaluate execution separately from answer generation; hybrid questions additionally require explicit source routing.
SUQL adds answer and summary functions over text to SQL. A semantic parser emits one hybrid query, while an optimizing compiler applies predicate pushdown, top-k pruning, and lazy evaluation.
CS224V splits task-agent evaluation into state updates and complete interaction: isolate the semantic parser, then test task completion, grounded queries, and valid actions with real users.
Genie Worksheets declare task capability as a form-like specification. A contextual semantic parser updates formal dialogue state while the runtime controls queries, actions, and responses.
CS336's first lecture does not treat building a language model from scratch as reenacting every old technique. It separates mechanics, mindset, and intuitions, then uses BPE to show how raw bytes become trainable tokens.
Lecture 1 of Stanford CS221 Autumn 2025 develops operational representations and algorithmic intuition through Overview: Defining Intelligence Under Resource Constraints.
Lecture 2 of Stanford CS221 Autumn 2025 develops operational representations and algorithmic intuition through Learning I: From Computation Graphs to Linear Regression.
Lecture 3 of Stanford CS221 Autumn 2025 develops operational representations and algorithmic intuition through Learning II: Linear Classification, Features, and Cross-Entropy.
Lecture 4 of Stanford CS221 Autumn 2025 develops operational representations and algorithmic intuition through Learning III: Deep Networks as Composable Computation Graphs.
Lecture 5 models search with states, actions, successors, and costs, then uses acyclic dynamic programming to show that an efficient algorithm still solves the wrong problem when state omits information needed by the future.
Lecture 6 of Stanford CS221 Autumn 2025 follows the official material on Search II: Priorities in UCS and A* and makes its assumptions and limits explicit.
Lecture 7 of Stanford CS221 Autumn 2025 follows the official material on MDPs I: Putting Uncertainty into State Transitions and makes its assumptions and limits explicit.
Lecture 8 of Stanford CS221 Autumn 2025 follows the official material on MDPs II: Learning Q-Values Without a Transition Model and makes its assumptions and limits explicit.
Lecture 9 moves from tabular RL to function approximation, derives REINFORCE with the log-derivative identity, and connects the derivation to the executable PyTorch implementation.
Lecture 10 extends single-agent search into adversarial game trees: expectimax averages chance outcomes, minimax takes the opponent's worst case, and alpha-beta removes irrelevant branches without changing the answer.
Lecture 11 first learns game values from experience with temporal-difference updates, then moves from sequential play to simultaneous games described by mixed strategies, minimax guarantees, and Nash equilibria.
Lecture 12 builds a joint distribution from random variables and factors, then uses Bayesian-network factorization to express conditional independence and make conditioning and marginalization executable.
Lecture 13 replaces costly exact inference with Gibbs sampling: resample one variable at a time from a conditional determined by its Markov blanket, then approximate query probabilities with sample frequencies.
Lecture 14 moves from maximum-likelihood counts and Laplace smoothing with complete data to EM, which alternates posterior responsibilities for latent variables with parameter updates.
Lecture 15 separates propositional syntax from semantics: model checking defines entailment through satisfying assignments, SAT finds witnesses, and inference rules must be judged for both soundness and completeness.
Lecture 16 compresses knowledge across objects with predicates, quantifiers, and functions, then derives conclusions through substitution, unification, and definite-clause forward inference while exposing termination and completeness limits.
Lecture 17 defines a language model as a chain-rule factorization of sequence probability, compares n-gram and neural conditional models, and shows how sampling, temperature, and evaluation shape generation.
Lecture 18 classifies AI's social effects as benefits, misuse, accidents, and structural harms, then connects fairness audits, research ethics, copyright, and platform terms to accountable institutional choices.
Lecture 19 uses the Economics of AI deck to connect compute, data, distribution, and organizational complements to GDP, labor, and ideas-driven growth.
Lecture 20 is Percy Liang's fireside chat on career and research, CS221 and Stanford, and AI's future, with every attribution tied to the official video and editorial synthesis kept separate from auto-caption uncertainty.
A slide-grounded reconstruction of Fall 2025 Lecture 1, covering Course map and tools, A common language for graph data, Hand-designed features and representation learning while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 2, covering Encoder-decoder view, Similarity and the objective, Random walks while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 3, covering From fixed embeddings to deep encoders, The message-passing framework, Aggregation and update while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 4, covering The GNN design space, Message, aggregation, and update, GraphSAGE while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 5, covering Graph-data augmentation, Feature and structural augmentation, Supervision and loss while documenting the classroom material unavailable to self-learners.
A Fall 2025 slide-grounded reconstruction of Lecture 6, covering What distinguishability means, The Weisfeiler–Lehman test, An upper bound for message passing while documenting unavailable classroom material.
A Fall 2025 slide-grounded reconstruction of Lecture 7, covering The perfect-GNN thought experiment, Three levels of standard-GNN failure, Identity-aware encoding while documenting unavailable classroom material.
A Fall 2025 slide-grounded reconstruction of Lecture 8, covering Self-attention and message passing, The scope of graph attention, Positional and structural encodings while documenting unavailable classroom material.
A Fall 2025 slide-grounded reconstruction of Lecture 9, covering Heterogeneous graph schemas, Relation-specific messages, R-GCN while documenting unavailable classroom material.
A Fall 2025 slide-grounded reconstruction of Lecture 10, covering Knowledge graphs and completion, Triple scoring, TransE and relation patterns while documenting unavailable classroom material.
A Fall 2025 slide-grounded reconstruction of Lecture 11, covering Graph formulation of recommendation, The matrix-factorization baseline, Message passing in NGCF while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 12, covering Limits of the tabular pipeline, Mapping relational databases to graphs, Temporal entity graphs while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 13, covering The multi-relational bottleneck, RelGNN composite message passing, Relation-specific aggregation while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 14, covering The goal of relational foundation models, Zero-shot relational transfer, PRODIGY's prompt graph while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 15, covering Limits of transductive KG embeddings, Entity-inductive link prediction, The relation graph while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 16, covering Complementary gaps in LLMs and GNNs, Text-attributed graphs, The LLM as predictor or encoder while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 17, covering From graph QA to agents, Multimodal retrieval in STaRK, Tool use and traversal while documenting the public-material boundary.
A Fall 2025 slide-grounded reconstruction of Lecture 18, covering The graph-generation problem and representation, Evaluating generation quality, GraphRNN's autoregressive factorization while documenting the public-material boundary.
The Fall 2025 conclusion studies roughly 315K GNN designs across 32 tasks: run a small set of anchor models, derive task similarity from rankings, and transfer the best designs from similar tasks.
Linear regression is more than a best-fit line: Chapter 1 connects squared loss to gradient descent, normal equations, maximum likelihood, and locally weighted regression.
Chapter 2 derives logistic loss from a sigmoid probability model, then contrasts it with the perceptron and extends it through softmax and Newton's method.
Chapter 3 uses exponential families, natural parameters, and link functions to place least squares and logistic regression inside one modeling template.
Chapter 4 models p(x|y) and p(y), using GDA, Naive Bayes, and Laplace smoothing to expose both the power and price of generative classification.
Chapter 5 replaces high-dimensional feature inner products with kernels, letting inner-product-based linear algorithms learn nonlinear functions without constructing the features.
Chapter 6 formalizes classification confidence as geometric margin, then builds an implementable SVM through Lagrange duality, kernels, and SMO.
Chapter 7 decomposes neural networks into composable modules and uses backpropagation and vectorization to explain how deep models can be trained efficiently.
Lecture 4 first shows that signed/unsigned conversion can preserve bits while changing meaning, that mixed comparisons may surprise, and how sign extension, zero extension, and truncation alter width. It then derives AND, OR, NOT, XOR, and bitmask idioms for testing, setting, clearing, and combining fields.
Lecture 3 starts with 32/64-bit address spaces, derives the ranges of unsigned and two's-complement signed integers, inversion-plus-one, and shared addition hardware, then separates unsigned modular arithmetic from C signed overflow and tests the model against four failure cases.
Lecture 5 extends masks to shifts, power-of-two and popcount tricks, then uses an absolute-value example to expose signed intermediate overflow at INT_MIN. Its second half establishes a GDB workflow around breakpoints, execution control, formatted printing, memory examination, and backtraces.
Lecture 2 puts C back into its Unix history and development environment: headers, main, printf, argc/argv, ssh, emacs, make, and executables. It then derives 8 bits = 1 byte, 256 byte patterns, and reliable conversion among decimal, binary, and hexadecimal.
Winter 2026 opens by explaining why CS107 goes below programming-language abstractions: from bytes and memory through assembly and heap allocators. It then lays out the 40/10/20/30 grading structure and closes with a first tour of the Unix command line.
Starting with elements, subsets, and power sets, this lecture culminates in Cantor's diagonal proof that no set is as large as its own power set.
The even-square and odd-sum examples show how arbitrary choices, assumptions, witnesses, and a want-to-show become a checkable direct proof.
This lecture identifies exactly when an implication is false, then turns quantified negation, contraposition, and contradiction into checkable proof tools.
Propositional logic abstracts English statements into Boolean variables, then uses truth tables to check connectives, translation direction, and equivalences.
This lecture extends propositional logic into a language about objects: distinguish constants, predicates, functions, and propositions, then express some and every with existential and universal quantifiers.
Translate natural language one layer at a time: identify universal and existential forms, then handle quantifier order, negation, restricted quantifiers, and uniqueness.
A function is more than a formula: domain, codomain, totality, and determinism are essential, while the quantifiers defining involutions, injections, and surjections dictate their proofs.
This lecture uses surjections and a proof about birds to separate assuming from proving, then shows that involutions are injective and surjective and carries those ideas into function composition.
Two sets have equal cardinality when a bijection pairs their elements; Cantor's diagonal set defeats every function from S to its power set by constructing a value it misses.
This lecture moves from the formal definitions of graphs and digraphs to independent sets, vertex covers, and their complement relationship.
Induction is not a list of checked examples: establish a true starting point, prove that an arbitrary true case transmits truth to the next case, and invoke the induction principle.
This lecture connects starting from ordinary induction to induction may start later, following the official examples and proof obligations.
This lecture connects why begin with a weak computer to from device behavior to a state machine, following the official examples and proof obligations.
This lecture connects the dfa definition connects the first half of cs103 to regular means that some dfa exists, following the official examples and proof obligations.
This lecture connects the automata ladder measures power with languages to dfa transition tables, following the official examples and proof obligations.
This lecture connects from closure properties to a language syntax to regex is mathematics, not one library, following the official examples and proof obligations.
This lecture connects four equivalent descriptions of regularity to the precise finite-memory intuition, following the official examples and proof obligations.
This lecture connects from finite-state limits to recursion to the arithmetic grammar, following the official examples and proof obligations.
This lecture connects why the model changes after cfgs to long addition and local access, following the official examples and proof obligations.
This lecture connects the sample tm looks back from the end to beyond pairwise marking, following the official examples and proof obligations.
This lecture connects a quick quantifier audit for recognizers and deciders to why every decision problem can be represented as a language, following the official examples and proof obligations.
This lecture connects returning from r, re, and utm to three self-reference warm-ups, following the official examples and proof obligations.
This lecture connects defining and locating halt to why halt is recognizable, following the official examples and proof obligations.
This lecture connects the lava diagram's two classification tasks to the deck's operational reading of rice's theorem, following the official examples and proof obligations.
This lecture connects decidable does not mean feasible to efficiency requires choosing a resource, following the official examples and proof obligations.
The final deck reconnects proofs, graphs, automata, and computability, then maps those foundations to Stanford courses that use them.
CS107 Lecture 15 decomposes x86-64 mov operands into immediate, register, absolute, indirect, displacement, indexed, and scaled-indexed forms, then unifies pointer dereference and array access with D + R[b] + R[i]×s.
CS107 Lecture 16 connects b/w/l/q data widths, subregisters, movs/movz, lea, calling conventions, arithmetic and logic, and shifts through one method: establish operand width before tracing sources, destinations, and real memory accesses.
CS107 Lecture 18 connects ZF/SF/CF/OF to cmp, test, signed and unsigned conditional jumps, then reconstructs if statements, loops, dynamic instruction counts, setcc, and cmovcc.
CS107 Lecture 17 completes full-width x86-64 multiplication and division, traces %rip through instruction bytes, and uses direct and indirect jmp to show how execution leaves its default sequential path.
CS107 Lecture 19 traces %rsp, push/pop, call/ret, parameters, return values, stack locals, and caller/callee register discipline to build the ABI contract that preserves data and control across functions.
CS107 Lecture 14 dissects the ten x86-64 instructions for sum_array: addresses and machine bytes appear on the left, AT&T assembly on the right, and the reader's job is to recover C-level effects from opcodes, operands, registers, and control flow—not to write assembly from scratch.
CS107 Lecture 7 builds pointer-based string scanning with strchr, strstr, and strspn, then shows why valid content can still overflow a buffer: safety requires input rules, destination capacity, termination, and memory-error detection.
CS107 Lecture 25 builds the essential cache model from a concise deck: memory access costs are nonuniform, smaller and faster layers retain data likely to be reused, and temporal and spatial locality determine whether a program benefits.
CS107 Lecture 6 reduces C strings to character arrays, a terminator, and an address: every convenience in strlen, strcmp, strcpy, strncpy, and strcat depends on the caller preserving capacity and termination invariants.
CS107 Lecture 24 builds a measurement workflow with matrix multiplication and Callgrind, then examines GCC constant folding, common-subexpression elimination, dead-code elimination, strength reduction, code motion, and recursion-to-loop conversion. Optimization starts with bottleneck evidence.
CS107 Lecture 23 advances the explicit free list to in-place realloc: split a useful remainder when shrinking, absorb free right neighbors when growing, and allocate-copy-free only as a fallback, while preserving both the physical heap and logical list.
CS107 Lecture 13 upgrades a Boolean callback to a three-way comparator, then combines void *, element width, and const void * callbacks into a fully generic bubble sort before mapping the design to qsort, bsearch, lfind, and lsearch.
CS107 Lecture 12 first uses char * for byte-wise generic swap and rotate, then uses a function pointer to separate bubble sort's traversal mechanism from its ordering rule: void * abstracts data types, while callbacks abstract behavior.
CS107 Lecture 11 finishes the heap contracts of calloc, strdup, free, and realloc, then turns several typed swap functions into void * plus a byte count: C generics do not preserve an unknown type; they explicitly transfer responsibility for addresses, widths, and interpretation.
CS107 Lecture 21 starts with alignment, throughput, and utilization, then uses a bump allocator and an implicit free list to explain metadata, splitting, placement, internal and external fragmentation, and the need to coalesce freed blocks.
CS107 Lecture 22 replaces an implicit list with an explicit free list. Searches visit only reusable blocks, but every free block now has both physical neighbors and logical links, so unlinking, coalescing, and reinsertion must preserve both structures.
CS107 Lecture 8 starts with address-of and dereference, explains why C pointer parameters are still passed by value, and shows how int *, char *, and char ** can modify caller-owned ints, chars, and pointers respectively.
CS107 Lecture 9 uses seven C-string rules to separate array objects, pointer variables, and string literals: arrays often convert to first-element pointers in expressions, but storage, assignment, mutability, and sizeof remain different.
CS107 Lecture 20 places reverse-engineering capability in an ethical context: privacy has individual and social models, while trust combines reliance with a risk of betrayal. It then reviews process memory and shifts from heap-allocation client to allocator implementer.
CS107 Lecture 10 moves from sizeof and pointer arithmetic to stack-frame lifetime: returning a local array leaves a dangling pointer; malloc crosses function returns but makes NULL handling, size arithmetic, ownership, free, and leaks the programmer's responsibility.
CS107 Lecture 26 closes ten weeks through six big questions: representation, text, memory, generics, execution, and allocation. It checks the learning goals through the explicit allocator and points toward CS111 and other systems courses.
List outcomes first; only then assign probabilities to events.
A condition restricts the sample space to outcomes still compatible with the evidence.
Bayes’ theorem turns an easier generative direction into the inferential direction we need.
Decide whether order matters and repetition is allowed before choosing a formula.
A random variable maps outcomes to numbers; expectation is a weighted average, not necessarily an attainable value.
Expectation compresses a distribution into a weighted average; LOTUS handles transformed values, while linearity makes sums tractable even without independence.
Variance describes a random variable's spread; Poisson models counts in a fixed interval and approximates a large-n, small-p binomial.
A continuous variable assigns zero probability to a point and area to intervals; CDFs, Uniform, Exponential, and memorylessness build on that distinction.
Standardization maps Normal variables to Z; Phi, linear transforms, and continuity correction turn intervals and large binomials into computable probabilities.
A joint distribution retains the full relationship among variables; marginals, conditionals, independence, and Bayes extract different answers from it.
Inference multiplies each hidden-variable prior by an observation likelihood and normalizes; the same loop handles repeated evidence and discretized continuous beliefs.
A Bayesian network factorizes a huge joint through conditional independence; ancestral sampling generates joint samples, and rejection sampling filters them into a conditional.
The Multinomial extends two-category Binomial counts to many categories; the same PMF models documents as word counts for Bayesian authorship with log-scores.
A Beta distribution represents full belief about an unknown success rate; success/failure data updates two parameters for posteriors, smoothing, and Thompson-sampling decisions.
A few independent sums have closed forms; general IID sums become approximately Normal under the CLT, with continuity correction for discrete sums.
The bootstrap treats a sample histogram as a population proxy, resampling with replacement to approximate a statistic's sampling distribution, error bar, or null p-value.
Expected cost in randomized code can be conditioned on the first random choice; counting problems become indicator sums, often avoiding the full distribution entirely.
Surprise turns rare events into bits; entropy is expected surprise, information gain selects uncertainty-reducing questions, and KL measures excess cost from a model distribution.
MLE fixes observed data and optimizes parameters; log-likelihood turns products into sums, but a maximum can also lie on a boundary.
Logistic regression turns a linear score into a Bernoulli probability with sigmoid; the gradient xⱼ(y-ŷ) follows directly from the log-likelihood chain rule.
Classifier comparison requires held-out data, baselines, calibration, precision/recall, and an explicit fairness criterion—not accuracy alone.
A neural network stacks logistic units; a forward pass computes probabilities, while backpropagation reuses output error to obtain every gradient.
Lecture 1 follows shared I/O cards in the 1940s, batch processing, multiprogramming, and personal computers to explain how OS responsibilities accumulated as hardware costs and user needs changed.
Lecture 2 defines shared and private process/thread state, then uses fork, execvp, waitpid, and thread creation to show how the kernel creates execution units.
Lecture 3 follows running, blocked, and ready transitions to show how PCBs, context save/restore, and the dispatcher complete one CPU-control handoff.
Lecture 4 defeats each Too Much Milk attempt with an explicit schedule, deriving race condition, atomicity, critical section, and synchronization requirements from concrete interleavings.
Lecture 5 uses an eight-slot circular Pipe to prove that a mutex supplies exclusion, while a condition variable atomically releases the lock and blocks when a predicate is false; under Mesa semantics, wait must return to a while loop that rechecks the predicate.
Lecture 6 evolves a one-core interrupt-masking lock through multicore version 5, tracking guard, lock, and wait-queue state to prevent races and lost wakeups.
Lecture 7 extracts four necessary deadlock conditions from request/ownership graphs, then compares detection, prevention, and lock ranking; breaking circular wait is common in practice, but every module must obey one global order.
Lecture 8 moves from FIFO and round robin through the unimplementable SRPT ideal to adaptive priority queues and the multicore conflict among queue contention, core affinity, and work conservation.
Lecture 9 follows source through assembly, object, executable, and process, explaining the linker's three passes and how a dynamic loader resolves shared-library addresses through a jump table at startup.
Lecture 10 moves from predictable LIFO stacks to heap free lists, first/best fit, and slabs, then compares reference counting with mark-and-sweep across dangling pointers, leaks, cycles, and fragmentation.
Lecture 11's official PDF is byte-identical to Lecture 10; this article preserves that artifact gap and focuses on reachability, dangling pointers, leaks, reference-count cycles, and mark/compact garbage collection.
Lecture 12 defines trust as voluntary vulnerability, separates over-trust from untrustworthiness, and applies assumption, inference, and substitution to the Linux TCB, the xz attack, and AI-code policy.
Lecture 13 starts from the failures of single-tasking and load-time relocation, uses an MMU with base/bound to create isolated virtual and physical address spaces and traps, then introduces segmentation to escape one contiguous region.
Lecture 14's official PDF is byte-identical to Lecture 13; this article records the gap and focuses on how multiple base/bound/protection entries enable growth, sharing, and compaction while retaining fixed-count, fragmentation, and rigid-layout limits.
Lecture 15 uses fixed pages to remove inter-process external fragmentation, then connects x86-64's four-level walk, sharing and aliasing, and the TLB to trade-offs among translation speed, sparse tables, context switches, and page size.
Demand paging loads pages only when needed; present bits, precise exceptions, and restartable instructions let the kernel safely fill them from executables, zero-fill, or backing store.
Lecture 17 separates demand paging into fetching and replacement: MIN cannot know the future, exact LRU is too expensive, and Clock uses reference/dirty bits to find a page old enough to evict; when active working sets exceed RAM, even a 1% fault rate can cause an approximately 1,000-fold slowdown.
A disk hides mechanical seek and rotation behind a linear block API; modern I/O then uses memory-mapped registers, DMA queues, and interrupts so the CPU mainly issues commands and receives completions.
A file system maps durable byte collections onto disk blocks; contiguous, linked, and FAT allocation trade locality, growth, random access, and metadata cost.
The 4.3BSD inode uses direct, single-indirect, and double-indirect tiers so lookup depth scales with file size; FIFO, SPTF, SCAN, and CSCAN then trade seek cost, fairness, and wait time.
Block cache retains hot indexes, bitmap slack preserves placement choices, and fragments plus delayed allocation trade later, better information for locality.
Directories map text names to file-system-local inode numbers; hard links share inode identity and reference counts, while symlinks store paths and permit cross-filesystem references with loops and dangling targets.
A single file-system operation updates several blocks, but a crash can occur between any two writes; this lecture compares how fsck, ordered writes, and write-ahead logging trade recovery time, performance, durability, and consistency.
Lecture 24 continues from the WAL entry point into transactions, idempotent replay, and checkpoints, showing why consistency is not durability and why a journal does not replace fsync or backups.
Lecture 25 separates assumption, inference, and substitution as ways to establish trust, then examines how social recommendations, generative AI, and synthetic media amplify over-trust; the response is preserved provenance, independent validation, and coordinated responsibility.
Flash programs pages but erases whole units; an FTL hides the asymmetry with out-of-place mapping, then manages amplification through garbage collection, temperature segregation, wear leveling, and TRIM.
A VM expands the process interface into a machine interface; the hypervisor directly executes ordinary instructions, traps privileged operations, and virtualizes interrupts, I/O, and two-stage address translation.
Lecture 28 reduces the semester to concurrency, memory, and storage, then uses four ideas—virtualization, atomicity, locality, and layering—to explain how operating systems manage shared resources.
CS124 is the first course in Stanford's NLP branch. Its textbook is Jurafsky's own Speech and Language Processing, free online, and all nine assignment repos are public. But a banner sits on the course homepage: it will not be taught at all in AY 2026–27. And the chapter numbers the syllabus points at no longer match the August 2026 textbook.
CS221 lays AI out along one axis, and reflex models — deep learning — sit in the lowest slot, with states, variables and logic above them. When Percy Liang took over in Autumn 2025 he replaced the slides with runnable Python and wrote 'Cut constraint satisfaction problems :(' into the source of the first lecture — yet ExploreCourses and Stanford Online both still advertise constraint satisfaction as a course topic. The project has gone from 20% of the grade in 2019 to extra credit only.
CS224N has kept every course website since 2000 online. In Winter 2019, Transformers were lecture 14, taught by a guest. In Winter 2026 they are lecture 5, and every lecture after that assumes you already know them. The machine translation assignment is gone; assignment 3 now has you code a decoder-only Transformer from scratch, with pytest suites that run on your laptop.
CS224U's teaching material isn't a slide deck — it's an Apache-2.0 GitHub repo holding the lecture notebooks, all three assignments, and the grading document for the final project. But the on-campus course has skipped three straight academic years since Spring 2023, and ExploreCourses has it back on the books for Spring 2026-27. The official description still lists relation extraction and semantic parsing; the 2023 syllabus covers neither. And the data-loading cell in the first assignment breaks in a fresh environment today, on a Hugging Face compatibility change.
CS224V only became Agentic AI in the 2026–2027 catalog, and the rename changed nothing underneath: the course still translates natural language into formal semantics and constrains agents with SMT solvers and knowledge graphs instead of wiring frameworks together. Seven of the eleven mandatory readings come out of the instructor's own lab. Every slide deck is public, and the course site says outright that they are deliberately incomplete.
All six CS224W Colabs download and run today, and the first one needs only NetworkX — no PyG install at all. But the exam is 35% of the grade, the largest single piece, and it's an in-person closed-book sitting. The public recordings stop at 2021 and cover none of the current syllabus's second half: graph transformers, relational deep learning, LLM+GNN.
CS228's official prerequisite is a single line — 'basic probability theory and algorithm design and analysis' — with no named course. But ExploreCourses shows it was last offered in Winter 2024, and the next slot, Winter 2027, still has a blank instructor field. What a self-learner can actually get is cs228-notes: 16 chapters, complete, last touched in June 2025.
The three things you need to self-study CS229 run on three different clocks. The lecture notes are 278 pages and were recompiled in August 2026. The newest problem sets you can download are from summer 2020. The self-assessment Stanford Online tells you to attempt before enrolling is a PDF created in 2008. Seventeen lectures from spring 2026 are public, and the last three are mislabeled.
CS329Z is a new three-unit agent engineering course debuting at Stanford in Autumn 2026. Its first homework asks you to build RAG, tool calling and a ReAct loop from scratch with litellm, then rewrite the same components in DSPy and hand in the comparison. The course site lives in a public GitHub repo, and the commit log shows the assignment count dropping from three to two in mid-August — the one that got cut was 'Data for Agents'.
Of the seventeen regular CS336 lectures, only nine are executable Python programs; the other eight are PDF slide decks — and the split falls exactly along the two instructors. Assignment 1's handout carries eight 'Low-Resource Tips' for finishing it on a laptop. Assignments 2 through 5 carry none. The course page lists the hourly price of a B200; the handouts list how many B200 hours each problem needs.
CS103 teaches you how to write proofs, then teaches you what can't be proven — but the part nobody mentions is that it ships C++ programming assignments, starting with PS0: install Qt Creator. Its real asset is a shelf of homegrown 'Guide to X' handouts and a Proofwriting Checklist that graders actually deduct points against, all public. Solutions and practice exams sit behind Stanford login, and the Honor Code page explains why.
CS107 runs from Unix and C all the way to x86-64 and writing your own malloc, across seven assignments. But line up four archived syllabi and the course stops looking like one course: assignments are worth 40% in three quarters and 20% in Summer 2026, where in-class quizzes take 40%. The resubmission policy exists only in the quarters Cain taught; Troccoli's quarter has none. The one assignment that accepts no late days is the final heap allocator. And what blocks a self-learner isn't the autograder — it's that every starter repo lives on AFS.
Every lecture in CS109's Summer 2026 offering ships with an official LLM Learning Guide — six concepts, a Learn prompt and a Test me prompt for each, written week by week across the quarter for a total of 23 PDFs. The same course's honor code Rule 4 forbids asking an LLM to solve your homework, and 65% of the grade sits in proctored exam rooms. Those two facts are halves of one design.
CS111's nine assignments run from lambdas to crash recovery in a journaling file system. Reading the site page by page turns up three things the syllabus blurb never mentions: assignment 3 is the point of no return, because assignment 4 compiles your assignment 3 code; a whole block of the final exam asks for definitions of ethics terms, and the public practice sheet ships with answers; and pasting your own code into an AI tool to ask about it is written down, in plain words, as an Honor Code violation.
The first slide of CS161 names three goals: design, analysis, communication. The third one is why handwritten homework scores zero and why solutions have to read like a memo to a colleague. Of the eight problem sets, HW2 is the wall. The lecture notebooks exist to show that timing runs can't tell you which algorithm is faster. And the summer offering is a completely different course wearing the same number.
Splitting two n-digit integers in half still creates four recursive products and leaves the runtime at n². Karatsuba reconstructs the cross term with (a+b)(c+d)-ac-bd, cuts the branching factor to three, and reaches roughly n^1.585.
Lecture 2 turns 'fast' into a worst-case bound that can be proved. A loop invariant establishes InsertionSort's correctness while its worst case is n²; a recursion invariant and O(n) work per level give MergeSort O(n log n).
For T(n)=aT(n/b)+O(n^d), the central comparison is branching growth a versus per-problem shrinkage b^d. Equality makes every level equally heavy, a<b^d makes the root dominate, and a>b^d makes the leaves dominate; outside the template, use substitution.
Selection does not require sorting. Median of medians groups elements by five, selects the median of the group medians as a pivot, and guarantees that the larger recursive side has at most 7n/10+5 elements; substitution proves O(n) worst-case time.
Randomized QuickSort has O(n log n) expected time on every fixed input but Θ(n²) worst-case time. The valid proof does not substitute expected subproblem sizes into a recurrence; it computes the probability that each pair is compared.
The Ω(n log n) lower bound applies to comparison sorting. When integer keys can index buckets directly, stable Counting Sort can power Radix Sort and achieve O(n) under conditions such as M≤n^c.
Ordinary BST operations cost O(h) and can degrade to O(n); five red-black invariants cap the height at 2 log₂(n+1), giving search, insertion, and deletion worst-case O(log n) bounds.
A universal hash family only needs to keep the collision probability of every distinct key pair at most 1/n; that makes the expected bucket size below 2, yielding expected O(1), not per-operation worst-case O(1).
DFS and BFS both scan an adjacency-list graph in O(n+m); DFS finish times produce a topological order for a DAG, while BFS layers equal exact unweighted shortest-path distances.
Contracting each SCC always produces a DAG; first-pass DFS finish times order those components, and a second pass on the transposed orientation discovers exactly one SCC per DFS tree in O(n+m).
Dijkstra finalizes the minimum estimate and relies on nonnegative weights; Bellman-Ford repeatedly relaxes every edge, spending O(nm) to support negative edges and detect a negative cycle reachable from the source.
Dynamic programming starts by defining subproblems, derives a recurrence from optimal substructure, and evaluates states in dependency order; Bellman–Ford layers by edge count, while Floyd–Warshall layers by allowed intermediate vertices.
Lecture 13 turns dynamic programming into five steps: choose a state, derive transitions, fill the table, reconstruct a solution, and then improve the implementation. LCS takes O(mn), both knapsack variants take O(nW) pseudo-polynomial time, and maximum-weight independent set on a tree takes O(|V|).
A greedy algorithm is not merely 'pick what looks best.' It keeps one choice at each step and needs an exchange argument proving that the choice preserves an optimum. Lecture 14 develops that proof pattern through activity selection, weighted completion time, and Huffman coding.
The heart of MST algorithms is an invariant: the selected edges remain contained in some MST. The cut property proves that every step of Prim and Kruskal is safe.
Ford–Fulkerson augments through a residual network. When no path remains, residual reachability yields a cut equal to the flow, certifying max flow, min cut, and their equality.
Deferred Acceptance permits tentative choices to be revoked. Monotone proposals prove O(n²) termination and stability, with an outcome favoring the proposing side.
The finale recaps the CS161 toolbox and points toward LP duality, Reed–Solomon coding, and ML-assisted algorithms. Officially, this lecture has slides but no notes.
Stanford CS rests on CS103, CS107, CS109, CS111, and CS161; CS221 names three of those plus CS106B as preparation. This guide combines official prerequisites with an explicitly editorial reading order and marks public-material and offering risks.