| --- |
| license: other |
| tags: [meta-reasoning, qwen3_5, condgen] |
| --- |
| |
| # MR_midtrain_9B_v5_condgen |
|
|
| This is the **final step-4128 checkpoint**, not the best-validation checkpoint, |
| of a six-epoch V5 supervised midtraining run from the stock Qwen3.5-9B weights. |
| The model uses the `Qwen3_5ForConditionalGeneration` architecture and is |
| published with the vision tower in the flat `model.visual.*` key layout expected |
| by verl's Megatron bridge. The export changes only the names of 333 vision |
| tensors from `model.language_model.visual.*`; their values are not modified. |
| The vision tower is carried from the base model and was not a target of the |
| text-only SFT run. |
|
|
| ## Training data and format |
|
|
| The training split contained 88,115 examples: 49,188 exploration (E), 29,450 |
| meta-reasoning (MR), 6,477 final-answer (FA), and 3,000 termination traces. |
| It was derived from `HerrHruby/MR_midtrain_V5_sft` with additional termination |
| traces sampled from existing frontiers. The unchanged validation split had 258 |
| examples. Training used the V4 verl/FSDP recipe with a 65,536-token maximum |
| training length and the V5 attribution-aware tokenizer. |
|
|
| FA training targets retain the FA chain of thought through `</think>`, then emit |
| `<attribution>...</attribution>` before the final answer or proof. The tokenizer |
| preserves the V4 `<direction>`, `</direction>`, `<summary>`, and `</summary>` |
| tokens (IDs 248077–248080) and adds `<attribution>` and `</attribution>` as |
| atomic special tokens (IDs 248081–248082). The model's embedding size is |
| unchanged. |
|
|
| The final checkpoint's validation loss was 0.642673. The lowest validation |
| loss in the run was 0.642636 at step 2700, but that checkpoint is **not** the |
| one published here. These losses are training diagnostics, not a downstream |
| benchmark evaluation. |
|
|
| ## Compatibility |
|
|
| The flat vision-tower key layout matches the published |
| [`MR_midtrain_9B_v4_condgen`](https://huggingface.co/HerrHruby/MR_midtrain_9B_v4_condgen) |
| layout and is intended for verl/Megatron loading. It also retains the full |
| conditional-generation architecture for Transformers and vLLM. For text-only |
| vLLM serving, disable image and video inputs (for example with |
| `--limit-mm-per-prompt '{"image":0,"video":0}'`). |
|
|
| The export process first merges the final verl FSDP model shards into a |
| Hugging Face safetensors checkpoint, then re-keys the 333 vision tensors. |
| Optimizer and dataloader states are not part of this inference/RL-init export. |
|
|
