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Temperature sampling
Definition
Temperature sampling is a decoding method that draws a model's next token from a probability distribution adjusted by a temperature value. Lower positive temperatures concentrate probability on likely tokens; higher temperatures spread it more broadly. The model then conditions its next prediction on the selected token. Repeating this process generates a sequence whose variability depends on both the model and the decoding settings.
What it means
Temperature is the control parameter, while temperature sampling is the procedure that uses it to make random selections. This distinction matters because changing a temperature setting may have no effect when a system is configured to use a different decoding method.
Sampling does not choose every possible next token with equal probability. It draws according to the adjusted weights. A lower-probability token can be selected, but it is less likely than a higher-probability one at that step.
Because each selected token becomes part of the next context, an early difference can lead to a substantially different continuation. A complete response is not ordinarily drawn in one operation from a fixed menu of finished answers.
How it works
For each generation step, obtain the model's scores for possible next tokens. Divide the scores by a positive temperature and convert them to probabilities using softmax. Draw one token using those probabilities, append it to the context, and repeat until the stopping condition is reached.
When working from probabilities at temperature 1, the equivalent transformation raises each probability to the power 1/T and then normalizes the results. This concentrates or flattens the distribution without changing the ranking of unequal probabilities.
A practical implementation may also filter candidates or apply other score adjustments. Record their order and settings when reproducing an experiment. Plain temperature sampling, top-k sampling, and top-p sampling are related but distinct choices; a system can combine them rather than using only one.
Three practical examples
1. A story-writing exercise samples several continuations from one opening and compares whether the variants remain consistent with the characters and setting.
2. A title-generation tool produces alternatives for human selection, using a documented sampling setup rather than assuming repeated requests must give identical wording.
3. A model evaluator repeats a set of prompts under a fixed sampling configuration to estimate variation in task success, instead of reporting only one conveniently successful answer.
Think of it this way
Think of walking through a branching garden, choosing each turn using a weighted draw. Temperature changes how strongly the most favored path dominates each local choice.
The analogy has limits. The available paths and their weights are recalculated from the evolving context, and attractive local turns do not guarantee a good destination. In language generation, a high-probability token can still contribute to an incorrect or unhelpful answer.
Worked example
Suppose three next-token options have probabilities 0.6, 0.3, and 0.1 before temperature scaling. At T = 0.5, square them to obtain weights 0.36, 0.09, and 0.01. Divide by their total, 0.46, to obtain approximately 0.7826, 0.1957, and 0.0217.
One way to visualize a draw is to assign consecutive intervals on the range from 0 to 1. The first option covers values below 0.7826, the second covers the next interval up to approximately 0.9783, and the third covers the remainder. A random value of 0.90 selects the second option.
At T = 1, that same illustrative value would fall in the third option's interval under the same ordering convention. After the selected token is appended, the model supplies a new distribution for the next step. This example demonstrates one draw; it does not predict the probabilities of complete answers.
Illustrative case study
Fictional case: Northlight Learning asks a model to write short practice dialogues. The team initially reviews only the first generated dialogue for each lesson and overlooks variation between repeated runs.
It then generates a predefined number of samples per lesson using a recorded temperature and checks each for vocabulary level, topic coverage, and unsupported claims. Reviewers compare the proportion that meet all requirements, alongside how repetitive the acceptable dialogues are.
This fictional procedure makes variability visible. It does not assume that the setting with the largest number of distinct dialogues is the best educational choice.
Common misconceptions and mistakes
Do not confuse a sample with the model's single highest-probability choice. Sampling intentionally allows other candidates to be selected.
Do not infer that a token with 10% probability must appear exactly ten times in 100 independent draws from an unchanged distribution. Counts fluctuate, and language generation usually changes the distribution after each token.
Avoid treating one appealing sampled response as evidence of stable performance. Also avoid using zero directly in the positive-temperature formula. Systems that accept a zero setting normally handle it as a special case, and that behavior must be checked in their documentation.
Business use
Temperature sampling is useful when variation is part of the product, such as drafting alternatives or creating practice material. Its business value depends on the quality of the resulting options and the cost of reviewing them.
Define how many samples are generated, how selections are made, and whether unsuccessful samples count in evaluation. Recording only the chosen output can hide a workflow that requires substantial retries. Compare complete production procedures, including review effort, rather than comparing a carefully selected sample with another system's first response.
People also ask
Can repeated requests produce the same response?
Yes. Sampling permits variation but does not require every result to differ, especially when probability is concentrated.
Does a random seed make every deployment reproducible?
A seed can help reproduce random draws in a controlled setup. Model versions, implementation details, and other sources of variation still matter.
Is temperature sampling the same as choosing the most likely token?
No. Greedy decoding chooses a highest-scoring token directly. Sampling draws from a distribution, even when that distribution strongly favors one token.
Check your understanding
A sampled answer succeeds once. What further evidence is useful before relying on this generation setup?
Answer: Repeat representative tasks using a predefined evaluation procedure. Measure success and variation across samples, including failures, and record the full decoding configuration.
Related terms
- Temperature
- Decoding
- Softmax
- Greedy decoding
- Top-k sampling
- Top-p sampling
- Response set
- categorical distribution
- random seed
Learn next
Learn categorical sampling to understand the weighted draw at one step. Then study top-p sampling and evaluation across repeated generations, distinguishing candidate diversity from the fraction of outputs that actually satisfy the task.
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Sources
Hugging Face Transformers, generation strategies and temperature utility: https://huggingface.co/docs/transformers/main/en/generation_strategies and https://huggingface.co/docs/transformers/main/en/internal/generation_utils
Primary implementation of score scaling: https://github.com/huggingface/transformers/blob/main/src/transformers/generation/logits_process.py
Documentation and the implementation were read for sampling behavior and positive-temperature scaling. The three-option calculation, evaluation design, and Northlight Learning case are original teaching illustrations.
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