FrequencyPenalty

FrequencyPenalty is an additive penalty proportional to how many times each token has appeared in the penalty window. The more often a token appears, the larger the penalty.

Quick reference
Type float
Default 0.0 (disabled)
Range 0.0 = disabled, typical 0.0 – 1.0
Category Repetition penalty
Field on SamplerParameters.FrequencyPenalty

What it does

For each token in the penalty window, compute count × FrequencyPenalty and subtract that from the token’s logit. Tokens that appeared ten times get penalized ten times as hard as tokens that appeared once.

  • 0.0 (default) — disabled.
  • 0.1 – 0.3 — moderate; common words stay usable but over-used ones get suppressed.
  • 0.5+ — aggressive; breaks repetition but risks under-generating common function words (articles, prepositions).

FrequencyPenalty is the finest-grained of the three penalties: RepetitionPenalty is binary-ish on the token, PresencePenalty fires once per token, and FrequencyPenalty scales with count.

When to change it

Scenario Value
Disabled 0.0 (default)
Discourage over-used words 0.2
Strong anti-repetition when other penalties do not suffice 0.5
Stacks with others; tune one penalty at a time

When experimenting, enable one penalty at a time and raise until looping stops. Enabling all three at once with aggressive values produces awkward output.

Example

var preset = new Qwen25Preset();
preset.SamplerParameters.FrequencyPenalty = 0.3f;
// Over-used words get progressively suppressed.

using var api = AsposeLLMApi.Create(preset);

Interactions

What’s next

PresencePenalty DynatempRange