DryPenaltyLastN

DryPenaltyLastN controls how far back DRY looks when scanning for phrase repetition. It determines the size of the generation window scanned for matches.

Quick reference
Type int
Default 0 (scan all available context)
Range 0 = unlimited; > 0 = window size
Category Phrase-level repetition penalty
Field on SamplerParameters.DryPenaltyLastN

What it does

DRY scans the last DryPenaltyLastN tokens of generation for consecutive-token sequences matching whatever the model is about to emit.

  • DryPenaltyLastN = 0 (default) — scan all available tokens; no distance limit.
  • DryPenaltyLastN = 512 — only the last 512 tokens are scanned for matches. Older content is ignored.
  • DryPenaltyLastN = 128 — very local; catches only immediate phrase repeats.

Narrowing the window speeds up DRY scanning slightly and relaxes the constraint for long conversations where older repeats are benign.

When to change it

Scenario Value
Default (scan all) 0
Long conversations, focus DRY on recent output 512
Very local enforcement 128

Most deployments leave DryPenaltyLastN = 0. Raise only if DRY is catching repeats from very old conversation history that are acceptable in your domain.

Example

var preset = new Qwen25Preset();
preset.SamplerParameters.DryMultiplier = 0.8f;
preset.SamplerParameters.DryPenaltyLastN = 512;  // only scan last 512 tokens

using var api = AsposeLLMApi.Create(preset);

Interactions

  • DryMultiplier — gate; DryPenaltyLastN only matters when DRY is active.
  • Other DRY knobs operate within this window.

What’s next

DryAllowedLength DrySequenceBreakers