"HF fine-tune gap matrix (SSOT ↔ code)"

HF fine-tune gap matrix (SSOT ↔ code)

Maps remaining risks and resolved items to modules and severity. See capability matrix for the live feature table.

Active gaps / risks

Gap / riskLocationSeverity
Burn: NF4 frozen base not wired into Mens train pathPrimitives: vox-tensor lora.rs (QLoRA roadmap / f32 LoRA today); full graph + merge: vox-populi mens/tensor/lora.rs; workspace Burn 0.19 has quantization building blocks — not integrated as frozen NF4 bases for LoraVoxTransformerHigh — integration backlog (not physics-limited); single-kernel QLoRA on Burn remains unscoped until designed against Burn quant APIs + optimizer/device story
Burn: LoraAttention::merge() when use_rope == truecrates/vox-populi/src/mens/tensor/lora.rs merge() — asserts / rustdoc: RoPE cannot fold into static merged linearsMedium (serve/merge for RoPE stacks only)
Candle: proxy stack (o_proj / c_proj + LM head), not full causal blockscandle_qlora_train.rs, ADR 006/007High (cross-kernel parity)
qlora-rs API: sequential QuantizedLinear onlyADR 007Medium (full-graph Candle training)
Cross-stack logits parityNo end-to-end NF4 vs Burn full-graph LM assertionMedium (primitives: matmul, biased linear (candle_burn_f32_linear_lm_logits_parity), Tier B NF4 dequant reference linear (candle_burn_nf4_dequant_lm_reference_parity), CE on shared f32 logits)
Burn *.bin ↔ Candle candle_qlora_adapter.safetensorsNo automatic rename/layout bridge (tensor/artifact_bridge.rs + merge_qlora guard)By design — operator must pick the kernel-appropriate merge command

Resolved / mitigated (was “gap”, now implemented)

ItemResolution
Burn LoraAttention::merge() placeholder MHAReal MultiHeadAttention merge for non-RoPE GPT-style attention; regression tests in lora.rs / Burn stack tests
Burn HF load beyond embeddingsGPT-2 decoder warm-start in burn_hf_load.rs (Q/K/V from c_attn, MLP, norms, wpe, ln_f, optional lm_head)
Merge UX: wrong adapter typemerge-qlora rejects *.bin with SSOT-linked copy from tensor/artifact_bridge.rs (MERGE_QLORA_REJECTS_BURN_BIN); aliases documented in SSOT / ref-cli.md
  • Mens training SSOT — merge table and regression commands.
  • Mens LLM PR checklist — duplication, flags, layouts, merge, parity tiers.
  • crates/vox-populi/src/mens/tensor/finetune_contract.rs — contract gates.