[None][docs] Fix beamWidth default value and valid range in gpt-runtime.md

[fuergaosi233]

Background

docs/source/legacy/advanced/gpt-runtime.md documents beamWidth with an incorrect default value and an invalid minimum range. The table states:

| `beamWidth` | ... | [0, 1024] | `0` (disable beam search) |

However, the C++ source code tells a different story.

Code Evidence

cpp/include/tensorrt_llm/runtime/samplingConfig.h:

// Line 107 — default is 1, not 0:
explicit SamplingConfig(SizeType32 beamWidth = 1)

// Line 245 — 0 is explicitly invalid:
valid &= (beamWidth > 0);

// Line 249 — error message confirms 0 is rejected:
"Requested beam width %d is incorrect. Must be > 0. To de-activate beam searching set beamWidth to 1."

The code:

1. Defaults beamWidth to 1 (not 0)
2. Validates that beamWidth > 0 — value 0 is INVALID and triggers an error
3. Explicitly states that beam search is disabled by setting beamWidth = 1, not 0

Changes

-|        `beamWidth`        | width for beam-search algorithm |         Int         |       \[0, 1024\]        | `0` (disable beam search) |
+|        `beamWidth`        | width for beam-search algorithm |         Int         |       \[1, 1024\]        | `1` (greedy/sampling; beam search disabled) |

• Correct the minimum range from [0, 1024] to [1, 1024]
• Correct the default from 0 to 1
• Align the description with the error message in samplingConfig.h

Summary by CodeRabbit

• Documentation
  • Updated the beamWidth parameter documentation with revised default value, allowed range, and clarification on beam search behavior.

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📥 Commits

Reviewing files that changed from the base of the PR and between c5b0372 and 90374fd.

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• docs/source/legacy/advanced/gpt-runtime.md

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📝 Walkthrough

Walkthrough

This PR updates the documentation for the beamWidth sampling parameter in the GPT runtime configuration table, changing its default value from 0 to 1 and the valid range to start at 1 instead of 0, while adding clarification about when beam search is disabled versus enabled.

Changes

beamWidth Parameter Documentation

Layer / File(s)	Summary
beamWidth parameter documentation docs/source/legacy/advanced/gpt-runtime.md	Updated the beamWidth parameter row in the beam-search configuration table to change the default value from 0 to 1, update the valid range to start at 1, and clarify that beam search is disabled under the default greedy/sampling setting.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: fixing the beamWidth default value and valid range in the documentation file.
Description check	✅ Passed	The description comprehensively explains the issue, provides code evidence, and clearly documents the changes, though some PR checklist items are not completed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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