A SHARED VOCABULARY

Words behind the words.

Short definitions to get your bearings. Follow a term into a complete explanation.

254 terms

Absolute position#
A location measured from a sequence’s beginning, such as position 12. It differs from the distance between two tokens.
Abstention#
Declining to supply an unsupported answer when the available evidence is insufficient. Its usefulness depends on when the system abstains and when it can answer.
Activation#
A value computed while processing an input. Activations depend on the current sequence; parameters persist across ordinary requests.
Activation function#
A function applied within a network to transform a computed value. Nonlinear activation functions let stacked layers represent more than a single linear mapping.
API#
Application programming interface: a defined way for software components to request operations or exchange data. Having a language model does not automatically provide access to an API.
Architecture#
The arrangement and rules of a model’s computation, including its layers and connections. A checkpoint supplies particular parameter values for that arrangement.
Arithmetic parser#
A program that reads a restricted mathematical expression according to explicit rules. The calculator lab parses numbers and operators instead of executing user text as program code.
Artificial intelligence#
The broad field of building systems that perform tasks such as recognizing patterns, using language, or making decisions. The label does not establish human-like understanding.
Assistant message#
A message assigned to the assistant role in a conversation format, often containing a previous response or the response being generated.
Attention#
A mechanism that forms weighted combinations of value vectors using compatibility scores between queries and keys.
Attention matrix#
A table relating query positions to key positions. Its entries may be raw scores or normalized weights, depending on the table’s label.
Attention score#
A compatibility score between a query and key before softmax. It is not yet a normalized attention weight or a measure of factual truth.
Attention weight#
A coefficient describing how much an available value vector contributes to an attention mixture. These input-dependent coefficients are different from the model’s persistent learned weights.
Automatic differentiation#
Calculating derivatives by applying differentiation rules to the operations a program executes. Backpropagation is a reverse-mode form of this process.
Autoregressive#
Generating a sequence by conditioning each next prediction on the tokens available before it.
AWQ#
Activation-aware Weight Quantization: a weight-only method that uses activation statistics to guide which weight channels need protection from quantization error.
Backpropagation#
An efficient use of the chain rule to calculate how a loss changes with the model’s parameters.
Backward pass#
Propagating derivatives backward through a computation to obtain gradients. An optimizer must still apply an update to change the parameters.
Base model#
A pretrained model before a particular assistant-oriented post-training stage; it is not synonymous with a complete chat product.
Batch#
A set of training examples whose losses or gradients are combined for an update.
Batch size#
The number of examples or requests processed together in a batch. Its effect on speed and memory depends on the workload and implementation.
Batching#
Processing several examples or requests together. It can improve hardware utilization while changing memory use and how long an individual request waits.
Benchmark#
A specified evaluation dataset and procedure. Its scope determines what a score can support.
Bias#
An adjustable offset added to a weighted sum in a neural-network calculation. This mathematical meaning differs from social or statistical bias in a model’s behavior.
Bidirectional attention#
Attention that can use positions on both sides of the current position. Without another restriction, it is unsuitable for hiding future targets in ordinary next-token training.
Bigram#
A pair of consecutive tokens. A bigram language model predicts the next token using only the immediately preceding token.
Bit#
A binary unit with two possible values. Bit width describes how many bits a representation uses, not how many facts a model knows.
Bit width#
The number of bits used for a stored numeric value or representation. Lower bit width does not by itself specify total memory use or model quality.
Byte#
A unit of eight bits used to represent data. A written character can require more than one byte in a text encoding.
Byte fallback#
Representing an otherwise unsupported text piece using its encoded bytes. This is a tokenizer design choice, not a rule that all tokenizers behave identically.
Byte-pair encoding#
A family of tokenization methods that learns merges of frequently adjacent symbols. Exact preprocessing and vocabulary vary.
Causal attention#
Self-attention restricted to the current and earlier input positions. This prevents future input tokens from supplying an answer during next-token training.
Causal mask#
A restriction preventing a position from attending to later positions in a causal decoder.
Chain rule#
A rule for differentiating a composition: combine derivatives through the intermediate operations. Backpropagation applies it efficiently across a computation graph.
Chat template#
Rules for converting role-labeled messages into the token sequence a chat model expects, including separators and special markers.
Checkpoint#
Saved model parameters and sometimes optimizer state, allowing a run or model to be resumed or used.
Computation graph#
A record of numerical operations and their dependencies. It shows how outputs depend on intermediate values, inputs, and parameters.
Compute#
The computational work or resources used to train or run a model. Arithmetic, memory capacity, and data movement are different constraints.
Compute-optimal training#
Allocating a fixed training-compute budget among choices such as parameter count and training tokens to optimize a stated training objective. This need not minimize deployment cost.
Conditional probability#
The probability of an outcome given specified information. Next-token probabilities are conditioned on the available prefix.
Context#
The information available in the current model input and generated prefix. It is different from information encoded in the model’s learned parameters.
Context management#
Choosing which instructions, messages, and supporting material to supply within the available context budget. Removal, summarization, and retrieval have different tradeoffs.
Context window#
The bounded sequence available to a model computation. It is distinct from knowledge encoded in parameters.
Coordinate#
One component of a vector, such as the first number in [0.2, 0.8]. A coordinate does not automatically correspond to a human-readable concept.
Corpus#
A collection of text or other material assembled for training, evaluation, or analysis.
Cosine#
A function of an angle. For two nonzero vectors, the cosine of the angle between them measures directional alignment: 1 for the same direction, 0 for perpendicular directions, and −1 for opposite directions.
Cosine similarity#
The dot product of two nonzero vectors divided by the product of their lengths; a measure of directional alignment.
Cross-entropy#
A loss that, for a single observed target token, is minus the logarithm of its predicted probability.
Data contamination#
Evaluation information appearing in training or other unintended parts of the evaluation setup.
Data leakage#
Information reaching a training or evaluation step where it should be unavailable, such as test answers appearing in training data. It can make a result misleading.
Data mixture#
The proportions of different sources or categories encountered during training. Sampling rules can change the mixture without changing the stored files.
Dataset#
A defined collection of examples used for training, evaluation, or another task. Its selection and organization affect what a result can establish.
Decode phase#
The phase that repeatedly generates additional tokens from the available context. Its timing differs from processing the initial prompt.
Decoder-only transformer#
A transformer design that uses causal attention to generate continuations from preceding tokens, without a separate encoder stack in the basic architecture.
Decoding#
The procedure that selects output tokens from model scores, such as greedy selection or sampling.
Deduplication#
Removing repeated or sufficiently similar data according to a chosen procedure.
Deep learning#
Machine learning with neural networks that compose many layers of transformations. More layers alone do not guarantee better performance.
Derivative#
A measure of how a function changes with a small change to an input. Training uses derivatives to calculate how parameters influence loss.
Dimension#
For a vector, the number of coordinates it contains. Model and head dimensions specify how many numbers each representation uses.
Distribution shift#
A change between the examples or conditions used during development and those encountered later. Performance can change even when the model weights stay fixed.
Document index#
A searchable structure built from a document collection. Updating it can change retrieved evidence without retraining the language model.
Dot product#
Multiply corresponding coordinates of two equal-length vectors, then add the results. It depends on both their lengths and how their directions align.
DPO#
Direct Preference Optimization: a preference-based objective that can train a policy without a separate explicit reward-model stage.
Embedding#
A numerical vector associated with an item, such as a token, and learned or supplied for a task.
Embedding retrieval#
Finding candidate material by comparing learned vector representations of the query and documents. Similarity alone does not prove that a passage supports an answer.
Embedding table#
A matrix with an embedding vector for each vocabulary entry. A token ID selects the corresponding row.
End token#
A special token used to signal that generation should stop for a sequence. A separate length limit can also stop generation.
End-to-end evaluation#
Testing the complete workflow from the request through retrieval or tools to the final answer, rather than testing only one component with ideal inputs.
Epoch#
One pass through a defined training dataset; large training runs do not always organize all data into repeated complete passes.
Evaluation#
Measuring a model or complete system against defined examples, tasks, and criteria. Results support claims about the measured setting rather than every possible use.
Exponential#
The function exp(x), or e raised to the power x. Softmax exponentiates scores before normalizing them into probabilities.
External memory#
Information retained outside the model’s weights, such as saved conversation records or documents retrieved for a later request. The application must explicitly supply it again.
Feed-forward layer#
A transformation applied to each position, often expanding a representation, applying a nonlinearity, and projecting back.
Few-shot prompting#
Providing a small number of examples in the current prompt to demonstrate a task. This can guide behavior without updating model parameters.
Fine-tuning#
Further training of an existing model on a selected objective or dataset.
FlashAttention#
An exact attention implementation that reorganizes computation to reduce memory traffic and avoid storing the full attention matrix in the usual way. It does not make the whole model linear-time.
Floating-point arithmetic#
Arithmetic using a finite numerical format that can approximate a wide range of magnitudes. Rounding means some results differ slightly from exact real-number arithmetic.
Floating-point operation#
An arithmetic operation on floating-point numbers. FLOPs count work; FLOP/s measures how many operations are performed per second.
Forward pass#
Computing intermediate values and outputs from an input using the model’s current parameters. It does not by itself update those parameters.
Gated linear unit#
A neural-network component that multiplies one transformed branch by another gating branch. Variants are used in some transformer feed-forward layers.
Generalization#
Performance on examples or settings beyond those directly learned during training; it must be tested rather than assumed.
Generation#
Producing output tokens from a model. Ordinary autoregressive generation repeatedly predicts a distribution, selects a token, and adds it to the context.
GPTQ#
A post-training weight-quantization method using approximate second-order information to choose a compressed representation. Its quality and speed depend on the model and runtime.
GPU#
Graphics processing unit: a processor suited to running many numerical operations in parallel. GPUs are widely used for neural-network training and inference.
Gradient#
The collection of derivatives indicating how a scalar objective changes as its inputs or parameters change.
Gradient descent#
Updating parameters by subtracting a learning-rate-scaled gradient to seek lower loss. A finite step is not guaranteed to improve every example.
Greedy decoding#
Choosing a highest-scoring token at each step. It does not optimize every property of the whole resulting sequence.
Grounding#
Connecting an answer to supplied evidence or another verifiable source. A citation is useful only when its source actually supports the associated claim.
Grouped-query attention#
An attention design in which groups of query heads share key-value heads. It offers a sharing pattern between separate per-query key-value heads and a single shared set.
Hallucination#
A generated claim that is unsupported or false in the relevant context, even if phrased fluently.
Head dimension#
The number of coordinates in one head’s query, key, or value representation. Cache estimates must use the dimensions actually stored.
Held-out data#
Examples excluded from the parameter updates being evaluated. They help measure performance beyond those training examples, although leakage can compromise the separation.
Hidden state#
An intermediate vector computed while processing an input. Unlike a saved parameter, its value depends on the current sequence and layer.
Host application#
The software around a model that supplies inputs, handles tool requests, and presents results. It must enforce permissions rather than rely on generated text as authorization.
Identity projection#
A transformation that leaves its input vector unchanged. Its identity matrix has ones on the diagonal and zeros elsewhere; the teaching pipeline uses it for inspectable attention calculations.
In-context learning#
Behavior guided by examples or information in the input sequence, without requiring a parameter update.
Inference#
Computing outputs using a model; ordinary inference does not apply optimizer updates to its parameters.
Instruction tuning#
Fine-tuning on examples framed as instructions and desired responses to encourage the model to follow requests. It does not automatically connect the model to live information.
Inter-token latency#
The elapsed time between successive output tokens during generation. A system can start quickly yet generate the rest of an answer slowly.
Key#
A projected vector used to compute compatibility with a query in attention.
KV cache#
Temporary stored attention key and value tensors that can be reused during autoregressive generation.
KV head#
A distinct set of key and value projections used by attention. Several query heads can share it in grouped-query or multi-query designs.
Language model#
A model that assigns probabilities to language sequences or predicts language units from context. The models discussed here mainly predict the next token.
Large language model#
A language model with many learned parameters, usually trained on substantial amounts of text. There is no single parameter threshold that makes a model “large.”
Latency#
Elapsed time for an operation; time to the first output and time per subsequent token are different measurements.
Layer#
A stage of a neural network that transforms a representation. A transformer block contains several sublayers rather than a single operation.
Layer normalization#
Normalizing a layer’s representation using the mean and variance of its features, usually with learned scale and offset. It is different from making token probabilities sum to one.
Learning rate#
A setting controlling the scale of an optimizer update, alongside the optimizer’s other rules.
Lexical retrieval#
Finding material through matching words or other textual features, rather than learned embedding similarity. The retrieval lab uses a simple keyword score.
Likelihood#
The probability assigned to observed data, viewed as a function of model parameters. Training can seek parameters that make the observed examples more likely.
Linear transformation#
A mapping that preserves addition and scaling; matrix multiplication is a common example. Adding a bias makes the full mapping affine rather than strictly linear.
Log-probability#
The logarithm of a probability. For an autoregressive sequence, adding conditional token log-probabilities gives the sequence’s log-probability.
Log-ratio#
The logarithm of one positive quantity divided by another. DPO compares policy-to-reference probability ratios for preferred and rejected responses.
Logistic model#
A model that applies a sigmoid to a score to produce a probability for a binary outcome. The training lab uses a deliberately tiny example.
Logit#
An unnormalized score, often one per vocabulary item before softmax.
Longest-match tokenizer#
A tokenizer that repeatedly selects the longest matching vocabulary entry at the current text position. The site uses this simple rule for teaching; it is not BPE training.
Loss#
A scalar objective used to measure error for training or evaluation. Lower loss does not guarantee truthfulness.
Machine learning#
Building a model whose behavior is adjusted using data, rather than specifying every response as a hand-written rule.
Matrix#
A rectangular table of numbers. Multiplying a vector by a suitable matrix combines its coordinates to produce another vector.
Memorization#
Retention of training-specific information that may allow an example or passage to be reproduced.
Memory bandwidth#
The rate at which data can move to or from memory. A workload can be bandwidth-limited even when its processor can perform arithmetic quickly.
MLP#
Multilayer perceptron: a network of weighted transformations and nonlinearities; transformer feed-forward blocks are often MLPs.
Model#
A mathematical or computational system that maps inputs to outputs. In a trained language model, its calculations depend on numerical parameters learned from data.
Multi-head attention#
Running several attention computations with distinct projections, then combining their outputs. More heads do not automatically mean more independent facts or reasoning steps.
Multi-query attention#
An attention design in which multiple query heads share one set of key and value heads, reducing the amount of distinct key-value state.
Nat#
A unit of information or loss calculated using natural logarithms. A single-target loss of −ln(0.5) is about 0.693 nats.
Natural language processing#
Methods for computers to analyze, transform, or generate human language. Language modeling is one part of this wider field.
Natural logarithm#
The logarithm with base e. These loss examples use it to convert target probabilities into additive penalties.
Near-duplicate#
An example that differs in wording or formatting but substantially repeats another. Exact string matching can miss this overlap.
Negative log-likelihood#
A loss formed by taking minus the logarithm of the probability assigned to observed data. Lower values mean the model assigned greater probability to that data.
Neural network#
A model made of connected numerical transformations with adjustable parameters. Layers transform their inputs into intermediate representations and outputs.
Next-token prediction#
Estimating which token follows a given prefix. During training, the actual following token supplies the target; it need not be the only plausible continuation.
Nonlinearity#
An operation that is not a linear mapping. In a neural network, nonlinearities help the combined layers express more varied input-output relationships.
Normalization#
Putting values into a specified standard form. Probability normalization, text normalization, and layer normalization perform different operations; the surrounding context identifies which one is meant.
Numerical overflow#
A calculation exceeding the largest number representable in its numeric format. Directly exponentiating a very large logit can cause overflow.
Numerical precision#
How finely a numeric format represents values. Lower precision can save storage or computation but introduces different approximation errors.
Numerical stability#
Organizing a calculation to reduce errors from finite precision, overflow, or very small numbers. Subtracting the maximum before softmax is one example.
Optimizer#
An algorithm that updates parameters using gradients and, depending on the algorithm, additional state.
Optimizer state#
Extra values maintained by an optimizer, such as accumulated gradient statistics. They can require memory in addition to parameters and current gradients.
Output projection#
A transformation into the required output space. The final vocabulary projection produces logits; an attention block’s output projection instead combines head outputs.
Output reserve#
A portion of a request’s token budget set aside for the generated response. The shared-budget examples here are illustrative rather than a provider limit.
Overfitting#
Learning patterns specific to the training examples that do not transfer well to new examples or conditions. Low training loss alone cannot rule it out.
Parameter#
A persistent numerical value of a model, usually learned during training.
Parameter update#
An explicit change to model parameters, usually calculated by an optimizer from training signals. A different prompt can change outputs without such an update.
Partial derivative#
A derivative with respect to one input or parameter while holding the others fixed. A gradient collects these derivatives for several variables.
Perplexity#
The exponential of average token negative log-likelihood when natural logarithms are used. Compare it only under compatible data, tokenization, and averaging rules.
Policy#
The distribution a model uses to choose outputs or actions in a learning setup. This differs from a written safety rule or a context-retention policy.
Position embedding#
A vector used to represent a position in a sequence, often combined with a token embedding. It is one family of position mechanisms, not a universal design.
Position encoding#
Information that lets a model distinguish positions or relative positions in a sequence.
Post-training#
Further training after pretraining to shape behavior for selected tasks or preferences. It can include supervised fine-tuning and preference-based methods.
Post-training quantization#
Compressing an already-trained model into a lower-precision representation without running its full original training again. Here “post-training” describes when quantization happens, not assistant fine-tuning.
PPO#
Proximal Policy Optimization: a family of reinforcement-learning updates. Its clipped probability-ratio objective discourages overly large policy changes without hard-bounding every change.
Preference data#
Comparisons or judgments about which outputs are preferred under a specified task and rubric.
Preference learning#
Learning from judgments about which outputs are preferred under a task and rubric. Preference is contextual and does not automatically establish factual correctness.
Preference pair#
Two responses to a prompt with a judgment favoring one over the other. A chosen response can still contain errors.
Prefill#
Processing the supplied prompt before ordinary token-by-token decoding begins, including constructing the attention state needed for generation.
Prefix#
The sequence already available before the next token is predicted. It can contain supplied text and earlier generated tokens.
Pretraining#
An initial large-scale training stage, commonly using prediction objectives over broad data.
Probability calibration#
Agreement between predicted probabilities and observed frequencies on a specified task. A valid probability distribution is not automatically well calibrated.
Probability distribution#
Probabilities assigned to possible outcomes. For the discrete token distributions shown here, the probabilities are nonnegative and add to one.
Probability mass#
The sum of probabilities assigned to a group of discrete outcomes. Top-p sampling retains candidates containing a chosen amount of this mass.
Probability normalization#
Rescaling nonnegative values with a positive total so they add to one. After candidate filtering, renormalization makes the surviving probabilities form a distribution again.
Projection#
A transformation from one vector representation to another, often through a learned matrix. In transformer terminology it need not mean an orthogonal geometric projection.
Prompt#
The input supplied to a model for a request. It can include instructions, conversation text, examples, retrieved passages, and formatting the user does not directly see.
Prompt injection#
Instructions embedded in untrusted material that try to redirect a system away from its authorized task. Clear boundaries help but are not a complete defense by themselves.
Provenance#
Information about where a claim or piece of data came from, such as its document, date, and revision. It helps a reader check whether evidence is suitable.
Proxy#
A measurable stand-in for a broader goal. Optimizing a proxy can improve its score while missing something users actually care about.
Pseudorandom generator#
A deterministic algorithm that produces a random-looking sequence from an initial state. Reusing the seed repeats that sequence only when the algorithm and other conditions match.
Quantization#
Representing values with a smaller set of numerical levels, often to reduce storage and computation costs.
Quantization calibration#
Using representative examples to estimate which values or channels need care during quantization. This differs from checking whether predicted probabilities match observed frequencies.
Quantization error#
The difference between the reconstructed quantized value and its original value. The lesson’s examples state this sign convention explicitly.
Quantization step#
The spacing between adjacent reconstructed values in a uniform quantizer. Rounding to these levels introduces an approximation error.
Query#
A projected vector used to score which keys are compatible with the current attention position.
Query head#
One attention head’s query projection and resulting queries. Its count can differ from the number of distinct key-value heads.
RAG#
Retrieval-augmented generation: supplying retrieved material to a generation system as external evidence.
Reference policy#
A baseline model distribution used to compare or constrain the policy being trained. DPO uses its response probabilities as part of the preference objective.
Regularization#
Adding a constraint or penalty to influence which solutions training prefers. In preference training, a reference-based penalty can discourage large departures from a baseline policy.
Reinforcement learning#
Training a policy using rewards associated with its actions or outcomes. In language-model applications, tokens can be actions and completed responses can receive rewards.
Relative position#
The offset between two sequence positions, such as three tokens earlier. Position mechanisms can make this relationship available to attention.
ReLU#
Rectified linear unit: the activation function max(0, x). It leaves positive inputs unchanged and turns negative inputs into zero.
Residual connection#
An addition that lets a layer contribute an update to an existing representation.
Residual stream#
The running representation to which transformer sublayers add updates through residual connections. It contains input-dependent values rather than a separate set of saved model weights.
Residual update#
The change added to an existing representation through a residual connection. It can reinforce or cancel coordinates rather than only increase them.
Retrieval#
Finding relevant material in an external collection and supplying it to the system. Retrieving a document does not itself update model weights or guarantee a supported answer.
Retriever#
The component that selects candidate passages or records for a request. Its success must be checked separately from the model’s use of the retrieved material.
Reward#
A numerical training signal scoring an action or response under a specified objective. A higher reward does not necessarily mean greater truth or usefulness.
Reward hacking#
Increasing a measured reward by exploiting weaknesses in the scoring rule rather than achieving the intended goal.
Reward model#
A model trained to assign a score to outputs, often based on preference comparisons in an RLHF pipeline.
RLHF#
Reinforcement learning from human feedback; here, the reward-model-based family of post-training recipes.
Rotary position embedding#
RoPE: position-dependent rotations of query and key coordinates that make their attention interaction depend on relative position. It does not simply add a position vector to the input.
Sampling#
Drawing an output token from a distribution, potentially after temperature scaling or truncation.
Scalar#
A single number, rather than a vector or a table of numbers. A loss is commonly a scalar computed from many model outputs.
Scaled dot-product attention#
Compute query–key dot products, divide by the square root of key dimension, apply any mask and softmax, then form a weighted sum of value vectors.
Scaling law#
An empirical relationship between quantities such as model size, training data, compute, and measured loss. Its fitted range and assumptions limit what it predicts.
Score#
A number used to rank or measure something under a specified rule. A next-token logit, a retrieval score and an evaluation score measure different things and are not automatically probabilities.
Search query#
Text or another representation used to request matching material from a search system. This is different from an attention query vector.
Seed#
An initial state for a pseudorandom generator. It enables repeatability only when the rest of the computation is also held fixed.
Self-attention#
Attention whose queries, keys, and values come from representations of the same sequence. A mask can restrict which positions each query may use.
Self-supervised learning#
Training in which targets are derived from the supplied data itself, such as using the next token in a text sequence as the answer to predict.
Sigmoid#
The logistic function 1 / (1 + exp(−x)), which maps real numbers to values between zero and one. This transformation alone does not make a value a reliable probability.
Sinusoidal positional encoding#
A position representation built from sine and cosine functions at different frequencies. It was used in the original Transformer architecture.
Softmax#
A function that exponentiates scores and divides by their sum to obtain a probability distribution.
Special token#
A designated vocabulary entry used for a structural purpose, such as marking a boundary or the end of a sequence. Its meaning depends on the model’s format.
Stochastic gradient descent#
Gradient descent using an estimate from sampled training examples or a minibatch, rather than calculating the gradient over the entire dataset at every step.
Stopping rule#
A condition that ends generation, such as an end token or an output-length limit. Completing a fluent sentence does not itself stop every decoding loop.
Structured output#
Output organized according to a specified format or schema so software can interpret it. Correct formatting alone does not prove correctness or successful execution.
Subword#
A token unit smaller than a complete word, such as a common prefix or word fragment. A tokenizer can mix whole words and smaller pieces.
Summarization#
Replacing longer material with a shorter account of its relevant contents. Summaries can omit or distort details, so they are not lossless memory.
Supervised fine-tuning#
Further training on input–target examples, such as prompts paired with desired responses.
Synthetic data#
Examples generated by a program or another model instead of being directly collected from the original task setting. Such examples still need quality checks.
System message#
An application-supplied message used to express high-level instructions or context in a chat format. Role labels must be interpreted according to the system’s actual design.
Temperature#
A positive divisor applied to logits before softmax. Lower values concentrate probability on higher scores.
Tensor#
A numerical array that can have multiple axes. In model software, vectors, matrices, and batches of such arrays are represented as tensors.
Test set#
Examples reserved for evaluating a developed system. A credible test separates them from both training and the choices tuned to the test answers.
Text normalization#
Converting text to a specified consistent form before processing. Different normalization rules can change which character sequences a tokenizer receives.
Throughput#
The amount of work completed per unit of time, such as output tokens per second. High throughput across many requests does not guarantee low waiting time for one request.
tiktoken#
A byte-pair-encoding tokenizer library. Its encoding must match the model being studied; this site’s toy tokenizer does not reproduce its outputs.
Time to first token#
The delay before the first output token becomes available. It can include queuing and prompt processing, so it is not the same as total completion time.
Token#
One unit in a tokenizer’s vocabulary. It can be a word, part of a word, punctuation, bytes, or another symbol.
Token budget#
The allocation of token capacity to input material and any reserved output. Actual accounting depends on the model and system.
Token ID#
An integer label identifying a vocabulary entry. A larger ID does not mean greater importance or a more complex meaning.
Tokenization#
Converting text into the units and identifiers accepted by a model. The result depends on the tokenizer’s vocabulary and encoding rules.
Tokenizer#
The procedure that converts text into vocabulary entries and token IDs. Training a tokenizer and training a language model are distinct processes.
Tool call#
A structured request that a surrounding application may validate and execute; generating the request is not execution.
Tool result#
The data or error returned after a tool operation. A model’s claim that an operation ran is not a substitute for an actual result.
Tool use#
A workflow in which a model requests an operation and an application validates and executes it, then returns the result to the model.
Top-k#
A decoding restriction that retains a chosen number of highest-scoring candidate tokens before renormalizing.
Top-p#
Nucleus sampling: retain a smallest high-probability candidate set whose cumulative mass reaches a threshold, renormalize it, then sample. The number retained can vary.
Training#
Adjusting a model’s parameters using examples and an objective. Reading a prompt during ordinary inference does not itself perform this update.
Training data#
The examples used to update a model’s parameters. Their contents and sampling mixture influence what the model is exposed to.
Training objective#
The numerical goal used to guide parameter updates, such as reducing prediction loss. It is a measurable proxy for desired behavior, not every property a user may want.
Training target#
The observed or specified output against which a prediction is scored. In next-token training, it is the actual following token in the example.
Training-data extraction#
Attempting to elicit material from a model that was present in its training data. A failed attempt does not establish that every extraction method would fail.
Transformer#
A neural-network architecture using attention and other transformations to process sequences.
Transformer block#
A repeated part of a transformer containing attention, feed-forward transformations, and connecting operations such as residual additions and normalization. Exact arrangements vary.
Transition probability#
The probability of moving to a particular next token or state from the current one. The generator lab supplies these probabilities in a fixed table.
Truncation#
Shortening input by removing selected content. It can discard an important instruction or fact, so which content is removed matters.
Unicode#
A standard for representing characters and text across writing systems. Its characters, code points, and encoded bytes are different units.
Unicode code point#
A numbered position in Unicode. One visible character or emoji can be represented by several code points, so code points and visible characters are not interchangeable.
Uniform distribution#
A distribution giving the same probability to every candidate in a finite set. A uniform random draw over an interval is its continuous counterpart.
User message#
A message representing the user’s input in a conversation format. The complete model input may contain additional messages and context.
Validation set#
Held-out examples used to make development choices, such as selecting settings or checkpoints. Repeatedly tuning against them can make them less independent as a final test.
Value#
A projected vector mixed using attention weights.
Vector#
An ordered list of numbers used to represent an item or an intermediate result. A two-dimensional drawing is only a small example of this representation.
Vector norm#
A measure of vector length. The cosine-similarity examples use the Euclidean norm: the square root of the sum of squared coordinates.
Vocabulary#
The finite set of token IDs recognized by a tokenizer and its corresponding model.
Weight#
A number that scales a contribution in a computation. Model weights are learned parameters; attention weights are input-dependent coefficients computed during a forward pass.
Weight tying#
Reusing the same learned parameter array for more than one role, such as input embeddings and the final vocabulary projection.
Weight-only quantization#
Quantization applied to model weights while other quantities may use higher precision. It reduces weight storage without necessarily shrinking every part of the workload.
Weighted sum#
Multiply each number or vector by its assigned weight, then add the results. Attention uses this operation to mix value vectors.
Workflow#
An ordered set of steps performed by an application, such as receiving a question, retrieving information, calling a tool and presenting a response. The workflow includes more than the underlying model.
Zero vector#
A vector whose coordinates are all zero. It has no direction, so cosine similarity with it is undefined.
Zero-shot prompting#
Asking for a task without supplying worked demonstrations of that task in the current prompt. The model still brings its prior training.