ttground-r1-ckpts

Ground-R1 reproduction checkpoints for the demystify study.

Naming convention

Checkpoints are namespaced by training stage, because ablation/variant names overlap between the two matrices (a baseline, ground or vanilla row can exist on both sides):

rl/<ablation>_seed<N>_ckpt<step>     e.g. rl/baseline_seed42_ckpt1000
sft/<variant>_seed<N>_ckpt<step>     e.g. sft/ground_seed42_ckpt125

Always include the seed. A checkpoint whose seed is not recorded cannot be placed in a seeded matrix row -- see williamium/ttground-r1-ckpts/baseline_ckpt1000_LEGACY for the counter-example that motivated this rule.

What is stored

Weights + configs only (model shards, index, tokenizer, preprocessor_config.json, chat_template.json, trainer_state.json). The DeepSpeed global_step*/ optimizer state is not uploaded: it is ~87G per RL checkpoint and has no use once a run has reached its step target. These checkpoints are therefore suitable for evaluation and warm-start, not for exact optimizer-state resume.

Provenance

• RL rows initialise from base Qwen2.5-VL-7B-Instruct. The paper is explicit that it does not cold-start RL from an SFT checkpoint ("we do not employ curated SFT dataset for cold-start training..."), and the upstream run_grpo_video.sh default matches.
• SFT runs use effective batch 128 (per-device 4 x grad-accum 4 x 8 GPUs), 125 steps ~ 0.494 epoch. A checkpoint whose trainer_state.json does not show epoch ~ 0.494 at step 125 was not trained at the reference batch size.