v1 vLLM run specifications

Models, context, prompts, sampling, and decode settings for prompt-v1 baselines

Companion: llm_v2_v3_enhanced_variants.md · persona_prompt_versions.qmd · config/vllm_presets.yaml

This page pins the prompt-v1 digital-twin generation stack used for the four published full-cohort baselines (N = 241 × 5 = 1,205 prompts each). Primary manuscript claims remain on these runs.


1 Models (prompt v1)

Model HF id Role in v1 ranking
Llama-3.1-8B-Instruct meta-llama/Llama-3.1-8B-Instruct Cautionary transit IP collapse
Llama-3.2-3B-Instruct meta-llama/Llama-3.2-3B-Instruct Best group bands / IP MAE among non-collapsed
DeepSeek-R1-Distill-Llama-8B deepseek-ai/DeepSeek-R1-Distill-Llama-8B Best pooled group MAE; tier-stable
Llama-3.3-70B-Instruct meta-llama/Llama-3.3-70B-Instruct Mode-collapse cautionary case

Export stamps (where documented): Llama-3.1 20260726_0221; Llama-3.2 …_20260726_0252; DeepSeek …_20260726_0324. Host for 8B/3B/DeepSeek: rogers-gpu-1.discovery.wisc.edu (RTX A5000; fp8 Marlin weight-only where stated).


2 Prompt styling (v1)

Layer v1 specification
Framing AI Terrarium / ICA 2026 digital twin: second-person narrative (“You are a …”), not checklist / “adopt this profile”
System prompt Inhabit persona; first-person CA self-report; JSON-only contract with group + interpersonal scores (6–30) and bands (low/moderate/high). Historical v1 system text omitted the later independent-subscale / non-deterministic / mobility-anti-bleed clauses
User prompt Cumulative narrative (demosemploymentgeotransitfull) + fused CA ask
Geo High-precision lat/lon (≈4 decimal)
Transit Full mobility dump including rides-per-day even when frequency was Never
Instruction style Instruct-tuned chat template (tokenizer.apply_chat_template); system + user messages; DeepSeek may emit <think> traces before JSON (post-processed at ingest)
JSON constraint Soft prompt only (“Respond with ONLY a JSON object”); no guided decoding in v1

Current tree code implements v2/v3.1-enhanced packaging (signal-first + anti-bleed). Historical v1 wording is preserved in this page and the published baseline write-ups, not as a live --prompt-version switch.


3 Runtime / decode (v1)

Values below are the predict_vllm.py / run_vllm.sh defaults that applied when published launchers omitted sampling flags. Write-ups documented quantisation and throughput for some models but often omitted temperature; treat greedy defaults as the reproducible reconstruction.

Parameter v1 value Notes
temperature 0.0 Greedy decode (code default)
top_p 1.0 Nucleus disabled
repetition_penalty 1.0 Off
seed unset Not reproducible across engines
max_output_tokens 256 CA JSON headroom
max_model_len (context) 8192 Shell / CLI default
quantization fp8 Documented for 3.1 / DeepSeek; assumed for siblings
gpu_memory_utilization 0.9
batch_size / save_freq 16 / 200 Checkpoint-resume CSV
tensor_parallel_size 1 (shell) / 2 (CLI default) Published 8B runs used TP=1 on A5000
Guided JSON false Prompt-only contract

Preset name for reconstruction: v1_baseline in config/vllm_presets.yaml.

VLLM_PRESET=v1_baseline ./scripts/run_vllm.sh
# or
python -m inference.predict_vllm --preset v1_baseline ...

4 Why these settings matter for RQs

  • Greedy + soft JSON recovered valid JSON at 100% for Llama instruct models, but Llama-3.3-70B collapsed to ≈93% constant prior (18, 12) — parse success ≠ twin success.
  • Fused transit dump + high-precision geo coincided with Llama-3.1 interpersonal MAE 4.67 → 8.17 and signed error −2.2 → +6.5 (systematic high-IP over-prediction).
  • No seed limits exact replay of stochastic siblings; v2/v3 enhanced presets fix seed=42.

Enhanced decode + packaging for future re-runs: llm_v2_v3_enhanced_variants.md.