CDF_EXPERIMENTS.md

# CDF / CST Experiment Protocol

This document defines the experiments for Curricular Diffusion Finetuning (CDF) on top of the existing T-Stitch codebase.
Run commands from the repository root unless a command explicitly changes directory.

Large runs require the original checkpoints, ImageNet or COCO data, ADM-style reference `.npz` files, and GPUs.
Paths in angle brackets are user-provided paths.


## 0. Experiment Runbook

This section is the execution checklist. Each experiment has a short code name that is used as the tmux session name, log directory, output directory, and table method key.

### 0.1 Experiment Table

| Code | Stage | Meaning | Train? | Primary output |
|---|---|---|---|---|
| `smoke_cst_fa` | sanity | 20-step LDM CST+FA smoke test; verifies data, LR scaling, boundary routing, and checkpoint writing. | yes | `logs/cdf/ldm/smoke_cst_fa` |
| `nft` | baseline / tuning reference | No-training LDM T-Stitch baseline on ImageNet for ratios `0.0,0.1,...,1.0`; gives the FID/IS reference before any tuning. | no | `outputs/cdf/ldm/nft` |
| `lr_sweep_cst_cosine` | tuning | Sweep CST cosine learning rate over `3e-6,1e-5,3e-5,1e-4` for 20k steps. | yes | `logs/cdf/ldm/lr_sweep_cst_cosine` |
| `lr_sweep_cst_cosine_eval` | tuning eval | Evaluate LR sweep on key ratios with 1000 samples. | no | `outputs/cdf/ldm/lr_sweep_cst_cosine` |
| `fa_sweep_cst_cosine` | tuning | Sweep FA weights after selecting `BEST_LR`. | yes | `logs/cdf/ldm/fa_sweep_cst_cosine` |
| `fa_sweep_cst_cosine_eval` | tuning eval | Evaluate FA sweep on key ratios with 1000 samples. | no | `outputs/cdf/ldm/fa_sweep_cst_cosine` |
| `schedule_ablation` | tuning / ablation | Compare curriculum schedules after selecting `BEST_LR`. | yes | `logs/cdf/ldm/schedule_ablation` |
| `schedule_ablation_eval` | tuning eval | Evaluate schedule ablation on key ratios or full ratios. | no | `outputs/cdf/ldm/schedule_ablation` |
| `cst_cosine` | main LDM | Full 200k-step CST with cosine curriculum, no FA. | yes | `logs/cdf/ldm/cst_cosine` |
| `cst_cosine_eval` | main eval | Evaluate `cst_cosine` on all ratios with 5000 samples. | no | `outputs/cdf/ldm/cst_cosine` |
| `cst_cosine_fa` | main LDM | Full 200k-step CST + FA with best FA weight. | yes | `logs/cdf/ldm/cst_cosine_fa` |
| `cst_cosine_fa_eval` | main eval | Evaluate `cst_cosine_fa` on all ratios with 5000 samples. | no | `outputs/cdf/ldm/cst_cosine_fa` |
| `frft` | baseline | Fixed-ratio fine-tuning, one junior checkpoint per ratio. | yes | `logs/cdf/ldm/frft` |
| `frft_eval` | baseline eval | Cross-ratio evaluation of all FRFT checkpoints. | no | `outputs/cdf/ldm/frft` |
| `senior_only` | baseline | Freeze junior and train senior only. | yes | `logs/cdf/ldm/senior_only` |
| `senior_only_eval` | baseline eval | Evaluate senior-only checkpoints. | no | `outputs/cdf/ldm/senior_only` |
| `fmgt` | baseline | Full model group training; jointly tune junior and senior. | yes | `logs/cdf/ldm/fmgt` |
| `fmgt_eval` | baseline eval | Evaluate FMGT checkpoints. | no | `outputs/cdf/ldm/fmgt` |
| `dit_nft` | DiT | DiT-S/2 + DiT-XL/2 no-finetuning T-Stitch baseline. | no | `outputs/cdf/dit/dit_nft` |
| `dit_cst_cosine` | DiT | DiT CST training with cosine curriculum. | yes | `logs/cdf/dit/dit_cst_cosine` |
| `dit_cst_cosine_eval` | DiT eval | Evaluate DiT CST on all ratios. | no | `outputs/cdf/dit/dit_cst_cosine` |
| `dit_cst_cosine_fa` | DiT | DiT CST + FA training. | yes | `logs/cdf/dit/dit_cst_cosine_fa` |
| `dit_cst_cosine_fa_eval` | DiT eval | Evaluate DiT CST+FA on all ratios. | no | `outputs/cdf/dit/dit_cst_cosine_fa` |
| `dit_sampler_ablation` | DiT ablation | Evaluate DiT CST under DDPM, DDIM, and DPM-Solver++. | no | `outputs/cdf/dit/dit_sampler_ablation_*` |
| `sd_nft` | SD / COCO | SD v1.4 + BK-SDM Tiny no-training T-Stitch on COCO. | no | `outputs/cdf/sd/nft_fixed` |
| `sd_deepcache` | SD / COCO | SD NFT plus DeepCache. | no | `outputs/cdf/sd/deepcache_i3_fixed` |
| `sd_tome` | SD / COCO | SD NFT plus ToMe token merging. | no | `outputs/cdf/sd/tome_05_fixed` |
| `sdxl_cst_cosine` | optional SDXL | Implemented SDXL/SSD-1B CDF training; not the SD v1.4 Table 2 setup. | yes | `logs/cdf/sd/sdxl_cst_cosine` |

Recommended order for finding the best training parameters:

```text
smoke_cst_fa -> nft -> lr_sweep_cst_cosine -> lr_sweep_cst_cosine_eval -> fa_sweep_cst_cosine -> fa_sweep_cst_cosine_eval -> schedule_ablation -> schedule_ablation_eval
```

Only after selecting `BEST_LR`, `BEST_FA`, and `BEST_SCHEDULE`, run the full 200k-step main experiments.

Sampling resume behavior:

- LDM evaluation skips a ratio if `samples/seed-...-ratio-<r>.npz` already exists.
- If sampling was interrupted before `.npz` creation, rerun the same command; existing PNG batches are skipped and missing images are generated.
- If `.npz` exists but `metrics-ratio-<r>.txt` is missing, rerun the same command; sampling is skipped and only the evaluator runs.
- If you want a completely fresh run, remove the corresponding output directory first.

Runtime logs:

- `run_cdf_experiments.sh` writes stdout/stderr to `run_logs/<command>/<timestamp>.log` and still prints to tmux.
- Set `CDF_RUN_LOG=/path/to/file.log` to choose a specific log path.
- Set `CDF_DISABLE_RUN_LOG=1` to disable automatic tee logging.

Evaluator device and metric resume:

- The runner tries the TensorFlow FID/IS evaluator on GPU first, then falls back to CPU if TensorFlow CUDA fails.
- Set `CDF_EVALUATOR_USE_GPU=1` to force GPU evaluator and fail if it cannot start.
- Set `CDF_EVALUATOR_USE_GPU=0` to force CPU evaluator.
- Existing metric files are skipped only when they contain both `FID:` and `Inception Score:`. Partial crashed logs are recomputed.

### 0.2 Tuning Commands

```bash
# LDM Smoke CST+FA
tmux new -s smoke_cst_fa
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
bash run_cdf_experiments.sh ldm-train-cst-fa \
    --data-root "$LDM_DATA" \
    --schedule cosine \
    --ratio-start 0.1 \
    --ratio-end 0.2 \
    --fa-weight 0.1 \
    --fa-boundary-width 10 \
    --logdir logs/cdf/ldm/smoke_cst_fa \
    --max-steps 20 \
    --batch-size 2 \
    --num-workers 0 \
    --learning-rate 1e-5 \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM NFT Baseline Before Tuning
tmux new -s nft
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-nft \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/nft \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM LR Sweep CST Cosine
tmux new -s lr_sweep_cst_cosine
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
for LR in 3e-6 1e-5 3e-5 1e-4; do
    bash run_cdf_experiments.sh ldm-train-cst \
        --data-root "$LDM_DATA" \
        --schedule cosine \
        --ratio-start 0.1 \
        --ratio-end 0.9 \
        --logdir "logs/cdf/ldm/lr_sweep_cst_cosine/lr_${LR}" \
        --max-steps 20000 \
        --batch-size 64 \
        --num-workers 0 \
        --learning-rate "$LR" \
        --scale-lr false \
        --gpus 0
done
```

```bash
# LDM LR Sweep CST Cosine Eval
tmux new -s lr_sweep_cst_cosine_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export TUNE_RATIOS=0.0,0.3,0.5,0.7,0.9,1.0
for LR in 3e-6 1e-5 3e-5 1e-4; do
    bash run_cdf_experiments.sh ldm-eval-cst \
        --checkpoint-dir "logs/cdf/ldm/lr_sweep_cst_cosine/lr_${LR}" \
        --eval-ratios "$TUNE_RATIOS" \
        --num-fid-samples 1000 \
        --num-sampling-steps 100 \
        --cfg-scale 3.0 \
        --ref-batch "$REF" \
        --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
        --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
        --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
        --output-dir "outputs/cdf/ldm/lr_sweep_cst_cosine/lr_${LR}" \
        --nproc-per-node 1 \
        --per-proc-batch-size 8
done
```

```bash
# LDM FA Sweep CST Cosine
tmux new -s fa_sweep_cst_cosine
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
for FA in 0.03 0.1 0.3; do
    bash run_cdf_experiments.sh ldm-train-cst-fa \
        --data-root "$LDM_DATA" \
        --schedule cosine \
        --ratio-start 0.1 \
        --ratio-end 0.9 \
        --fa-weight "$FA" \
        --fa-boundary-width 10 \
        --logdir "logs/cdf/ldm/fa_sweep_cst_cosine/fa_${FA}" \
        --max-steps 20000 \
        --batch-size 64 \
        --num-workers 0 \
        --learning-rate "$BEST_LR" \
        --scale-lr false \
        --gpus 0
done
```

```bash
# LDM FA Sweep CST Cosine Eval
tmux new -s fa_sweep_cst_cosine_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export TUNE_RATIOS=0.0,0.3,0.5,0.7,0.9,1.0
export BEST_LR=1e-5
for FA in 0.03 0.1 0.3; do
    bash run_cdf_experiments.sh ldm-eval-cst-fa \
        --checkpoint-dir "logs/cdf/ldm/fa_sweep_cst_cosine/fa_${FA}" \
        --eval-ratios "$TUNE_RATIOS" \
        --num-fid-samples 1000 \
        --num-sampling-steps 100 \
        --cfg-scale 3.0 \
        --ref-batch "$REF" \
        --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
        --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
        --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
        --output-dir "outputs/cdf/ldm/fa_sweep_cst_cosine/fa_${FA}" \
        --nproc-per-node 1 \
        --per-proc-batch-size 8
done
```

```bash
# LDM Schedule Ablation
tmux new -s schedule_ablation
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
bash run_cdf_experiments.sh ldm-train-cst-ablation \
    --schedule cosine,cst_v1,cst_v2 \
    --ratio-start 0.1 \
    --ratio-end 0.9 \
    --data-root "$LDM_DATA" \
    --logdir logs/cdf/ldm/schedule_ablation \
    --max-steps 20000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM Schedule Ablation Eval
tmux new -s schedule_ablation_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export TUNE_RATIOS=0.0,0.3,0.5,0.7,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-cst-ablation \
    --checkpoint-dir logs/cdf/ldm/schedule_ablation \
    --eval-ratios "$TUNE_RATIOS" \
    --num-fid-samples 1000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/schedule_ablation \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

### 0.3 Main LDM Commands

```bash
# LDM NFT
tmux new -s nft
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-nft \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/nft \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM CST Cosine
tmux new -s cst_cosine
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
export BEST_SCHEDULE=cosine
bash run_cdf_experiments.sh ldm-train-cst \
    --data-root "$LDM_DATA" \
    --schedule "$BEST_SCHEDULE" \
    --ratio-start 0.1 \
    --ratio-end 0.9 \
    --logdir logs/cdf/ldm/cst_cosine \
    --max-steps 200000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM CST Cosine Eval
tmux new -s cst_cosine_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-cst \
    --checkpoint-dir logs/cdf/ldm/cst_cosine \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/cst_cosine \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM CST Cosine FA
tmux new -s cst_cosine_fa
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
export BEST_SCHEDULE=cosine
export BEST_FA=0.1
bash run_cdf_experiments.sh ldm-train-cst-fa \
    --data-root "$LDM_DATA" \
    --schedule "$BEST_SCHEDULE" \
    --ratio-start 0.1 \
    --ratio-end 0.9 \
    --fa-weight "$BEST_FA" \
    --fa-boundary-width 10 \
    --logdir logs/cdf/ldm/cst_cosine_fa \
    --max-steps 200000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM CST Cosine FA Eval
tmux new -s cst_cosine_fa_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-cst-fa \
    --checkpoint-dir logs/cdf/ldm/cst_cosine_fa \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/cst_cosine_fa \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM FRFT
tmux new -s frft
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
bash run_cdf_experiments.sh ldm-train-frft \
    --ratios 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9 \
    --data-root "$LDM_DATA" \
    --logdir logs/cdf/ldm/frft \
    --max-steps 200000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM FRFT Eval
tmux new -s frft_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-frft \
    --checkpoint-dir logs/cdf/ldm/frft \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/frft \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM Senior Only
tmux new -s senior_only
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
bash run_cdf_experiments.sh ldm-train-senior-only \
    --ratios 0.1,0.3,0.5,0.7,0.9 \
    --data-root "$LDM_DATA" \
    --logdir logs/cdf/ldm/senior_only \
    --max-steps 200000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM Senior Only Eval
tmux new -s senior_only_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-senior-only \
    --checkpoint-dir logs/cdf/ldm/senior_only \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/senior_only \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# LDM FMGT
tmux new -s fmgt
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export LDM_DATA=$PREP/ldm
export BEST_LR=1e-5
bash run_cdf_experiments.sh ldm-train-fmgt \
    --ratios 0.1,0.3,0.5,0.7,0.9 \
    --data-root "$LDM_DATA" \
    --logdir logs/cdf/ldm/fmgt \
    --max-steps 200000 \
    --batch-size 64 \
    --num-workers 0 \
    --learning-rate "$BEST_LR" \
    --scale-lr false \
    --gpus 0
```

```bash
# LDM FMGT Eval
tmux new -s fmgt_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh ldm-eval-fmgt \
    --checkpoint-dir logs/cdf/ldm/fmgt \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 3.0 \
    --ref-batch "$REF" \
    --ldm-s-path "$REPO/ldm/pretrained_models/ldm_s.ckpt" \
    --ldm-path "$REPO/ldm/pretrained_models/ldm.ckpt" \
    --ae-ckpt "$REPO/ldm/pretrained_models/vq-f8/model.ckpt" \
    --output-dir outputs/cdf/ldm/fmgt \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

### 0.4 DiT Commands

```bash
# DiT NFT
tmux new -s dit_nft
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export MODEL_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/models
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export VAE_MODEL=$MODEL_ROOT/sd-vae-ft-ema
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh dit-eval-nft \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 1.5 \
    --solver ddim \
    --ref-batch "$REF" \
    --small-model DiT-S/2 \
    --large-model DiT-XL/2 \
    --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
    --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
    --vae-model "$VAE_MODEL" \
    --output-dir outputs/cdf/dit/dit_nft \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# DiT CST Cosine
tmux new -s dit_cst_cosine
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export DIT_DATA=$PREP/imagefolder/train
bash run_cdf_experiments.sh dit-train-cst \
    --data-path "$DIT_DATA" \
    --small-model DiT-S/2 \
    --large-model DiT-XL/2 \
    --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
    --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
    --schedule cosine \
    --ratio-start 0.1 \
    --ratio-end 0.9 \
    --results-dir logs/cdf/dit/dit_cst_cosine \
    --epochs 1400 \
    --global-batch-size 256 \
    --learning-rate 1e-5 \
    --nproc-per-node 1
```

```bash
# DiT CST Cosine Eval
tmux new -s dit_cst_cosine_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export MODEL_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/models
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export VAE_MODEL=$MODEL_ROOT/sd-vae-ft-ema
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh dit-eval-cst \
    --checkpoint-dir logs/cdf/dit/dit_cst_cosine \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 1.5 \
    --solver ddim \
    --ref-batch "$REF" \
    --small-model DiT-S/2 \
    --large-model DiT-XL/2 \
    --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
    --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
    --vae-model "$VAE_MODEL" \
    --output-dir outputs/cdf/dit/dit_cst_cosine \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# DiT CST Cosine FA
tmux new -s dit_cst_cosine_fa
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export PREP=$DATA_ROOT/imagenet-1k/cdf_prepared
export DIT_DATA=$PREP/imagefolder/train
bash run_cdf_experiments.sh dit-train-cst-fa \
    --data-path "$DIT_DATA" \
    --small-model DiT-S/2 \
    --large-model DiT-XL/2 \
    --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
    --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
    --schedule cosine \
    --ratio-start 0.1 \
    --ratio-end 0.9 \
    --fa-weight 0.1 \
    --fa-boundary-width 10 \
    --results-dir logs/cdf/dit/dit_cst_cosine_fa \
    --epochs 1400 \
    --global-batch-size 256 \
    --learning-rate 1e-5 \
    --nproc-per-node 1
```

```bash
# DiT CST Cosine FA Eval
tmux new -s dit_cst_cosine_fa_eval
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export MODEL_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/models
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export VAE_MODEL=$MODEL_ROOT/sd-vae-ft-ema
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh dit-eval-cst-fa \
    --checkpoint-dir logs/cdf/dit/dit_cst_cosine_fa \
    --eval-ratios "$RATIOS" \
    --num-fid-samples 5000 \
    --num-sampling-steps 100 \
    --cfg-scale 1.5 \
    --solver ddim \
    --ref-batch "$REF" \
    --small-model DiT-S/2 \
    --large-model DiT-XL/2 \
    --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
    --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
    --vae-model "$VAE_MODEL" \
    --output-dir outputs/cdf/dit/dit_cst_cosine_fa \
    --nproc-per-node 1 \
    --per-proc-batch-size 8
```

```bash
# DiT Sampler Ablation
tmux new -s dit_sampler_ablation
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export MODEL_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/models
export REF=$REPO/assets/fid_stats/VIRTUAL_imagenet256_labeled.npz
export VAE_MODEL=$MODEL_ROOT/sd-vae-ft-ema
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
for solver in ddpm ddim dpm-solver++; do
    bash run_cdf_experiments.sh dit-eval-cst \
        --checkpoint-dir logs/cdf/dit/dit_cst_cosine \
        --eval-ratios "$RATIOS" \
        --num-fid-samples 5000 \
        --num-sampling-steps 50 \
        --cfg-scale 1.5 \
        --solver "$solver" \
        --ref-batch "$REF" \
        --small-model DiT-S/2 \
        --large-model DiT-XL/2 \
        --small-ckpt "$REPO/dit/pretrained_models/dit_s_256.pt" \
        --large-ckpt "$REPO/dit/pretrained_models/dit_xl_256.pt" \
        --vae-model "$VAE_MODEL" \
        --output-dir "outputs/cdf/dit/dit_sampler_ablation_${solver}_50" \
        --nproc-per-node 1 \
        --per-proc-batch-size 8
done
```

### 0.5 SD / COCO Commands

The repository currently has COCO evaluation for SD v1.4 + BK-SDM Tiny, DeepCache, and ToMe. The training entry `sd-train-cst` exists for SDXL/SSD-1B in `sd/train_sdxl_tstitch.py`; it is not the SD v1.4 + BK-SDM Tiny Table 2 training setup.

```bash
# SD NFT
tmux new -s sd_nft
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export COCO_PROMPTS=$DATA_ROOT/coco/annotations/captions_val2014.json
export COCO_REF=$REPO/assets/fid_stats/coco_val2014_256.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh sd-eval-nft \
    --pipeline sd \
    --prompts "$COCO_PROMPTS" \
    --ref-batch "$COCO_REF" \
    --output-dir outputs/cdf/sd/nft_fixed \
    --limit 5000 \
    --ratios "$RATIOS" \
    --height 256 \
    --width 256 \
    --steps 50 \
    --guidance-scale 7.5
```

```bash
# SD DeepCache
tmux new -s sd_deepcache
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export COCO_PROMPTS=$DATA_ROOT/coco/annotations/captions_val2014.json
export COCO_REF=$REPO/assets/fid_stats/coco_val2014_256.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh sd-eval-deepcache \
    --pipeline sd \
    --prompts "$COCO_PROMPTS" \
    --ref-batch "$COCO_REF" \
    --output-dir outputs/cdf/sd/deepcache_i3_fixed \
    --limit 5000 \
    --ratios "$RATIOS" \
    --height 256 \
    --width 256 \
    --steps 50 \
    --guidance-scale 7.5 \
    --deepcache-interval 3
```

```bash
# SD ToMe
tmux new -s sd_tome
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export REPO=$PWD
export DATA_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/datas
export COCO_PROMPTS=$DATA_ROOT/coco/annotations/captions_val2014.json
export COCO_REF=$REPO/assets/fid_stats/coco_val2014_256.npz
export RATIOS=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0
bash run_cdf_experiments.sh sd-eval-cst \
    --pipeline sd \
    --prompts "$COCO_PROMPTS" \
    --ref-batch "$COCO_REF" \
    --output-dir outputs/cdf/sd/tome_05_fixed \
    --limit 5000 \
    --ratios "$RATIOS" \
    --height 256 \
    --width 256 \
    --steps 50 \
    --guidance-scale 7.5 \
    --tome-ratio 0.5
```

```bash
# Optional SDXL CST Cosine Training
tmux new -s sdxl_cst_cosine
cd /inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/T-Stitch
export MODEL_ROOT=/inspire/hdd/project/intelligentcreativedesign/dangshengqi-253114050252/z-anna/models
bash run_cdf_experiments.sh sd-train-cst \
    --pretrained_model_name_or_path "$MODEL_ROOT/stable-diffusion-xl-base-1.0" \
    --small_model_name_or_path "$MODEL_ROOT/SSD-1B" \
    --train_data_dir <image_text_train_dir> \
    --metadata_file <metadata.jsonl> \
    --output_dir logs/cdf/sd/sdxl_cst_cosine \
    --resolution 1024 \
    --ratio 0.9 \
    --ratio_schedule cosine \
    --ratio_start 0.1 \
    --ratio_schedule_steps 100000 \
    --train_mode junior \
    --max_train_steps 100000 \
    --train_batch_size 1 \
    --learning_rate 1e-5
```

## 1. Notation

Let `T` be the full DDPM training horizon. In the main ImageNet experiments, `T = 1000`.

Let `r in [0, 1]` be the junior ratio, i.e. the fraction of denoising responsibility assigned to the junior model.
CDF uses the same coarse-to-fine inference direction as T-Stitch:

```text
t_zeta(r) = floor((1 - r) * T)
junior interval = {t | t_zeta(r) <= t < T}
senior interval = {t | 0 <= t < t_zeta(r)}
```

With `T = 1000`, `r = 0.1` gives `t_zeta = 900`, while `r = 0.9` gives `t_zeta = 100`.
This is the exact schedule expected by the paper text: training moves from short junior responsibility to long junior responsibility.

During inference, sampling starts from high-noise timesteps and moves toward low-noise timesteps.
The junior model handles early high-noise/coarse steps, and the senior model handles late low-noise/refinement steps.

## 2. CDF Inference

Given a junior denoiser `eps_j` and senior denoiser `eps_s`, CDF inference selects the model by timestep:

```text
eps_CDF(x_t, t, y; r) =
  eps_j(x_t, t, y), if t >= t_zeta(r)
  eps_s(x_t, t, y), if t <  t_zeta(r)
```

Meaning:

- `r = 0.0`: pure senior model.
- `r = 1.0`: pure junior model.
- `0.1 <= r <= 0.9`: collaborative CDF/T-Stitch trajectory.
- NFT is exactly this inference rule without any CDF fine-tuning.

Default evaluation ratios:

```text
0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0
```

## 3. Training Objectives

### 3.1 Standard Diffusion Loss

All model families keep their native diffusion objective.
For LDM and DiT ImageNet experiments, this is epsilon prediction:

```text
x_t = sqrt(alpha_bar_t) * x_0 + sqrt(1 - alpha_bar_t) * eps
L_diff = E || eps - eps_theta(x_t, t, y) ||_2^2
```

For SD/SDXL, the same rule applies to the pipeline's native prediction type:

```text
target =
  eps, if prediction_type == epsilon
  v,   if prediction_type == v_prediction
```

### 3.2 Fixed-Ratio Fine-Tuning

FRFT trains the junior model for one fixed ratio `r0`.
The senior model is frozen.

```text
t_zeta = floor((1 - r0) * T)
t ~ Uniform({t_zeta, ..., T - 1})
L_FRFT(r0) = E || eps - eps_j(x_t, t, y) ||_2^2
```

Meaning:

- One checkpoint is trained for one ratio.
- To support 9 ratios, train 9 junior checkpoints.
- This tests whether ratio-specific specialization generalizes.

### 3.3 Curricular Stitching Training

CST trains one junior model over a moving ratio distribution.
The senior model is frozen.

Let `s = global_step / total_steps`.
Let `r_min = 0.1`, `r_max = 0.9`.

```text
r(s) = r_min + (r_max - r_min) * g(s)
t_zeta(s) = floor((1 - r(s)) * T)
t ~ Uniform({t_zeta(s), ..., T - 1})
L_CST = E || eps - eps_j(x_t, t, y) ||_2^2
```

Curriculum variants:

```text
linear:     g(s) = s
cosine:     g(s) = (1 - cos(pi * s)) / 2
cst_v1:     g(s) = sqrt(s)     # large-ratio-biased, harder ratios appear earlier
cst_v2:     g(s) = s^2         # small-ratio-biased, easier ratios last longer
staircase:  g(s) = floor(K * s) / K, default K = 8
```

Meaning:

- CST turns ratio into a training variable.
- The final junior checkpoint should work for all evaluation ratios.
- `cst_v1` and `cst_v2` are the main ablation schedules.

### 3.4 Feature Alignment at the Stitching Boundary

Feature Alignment (FA) aligns junior and senior representations near the handoff boundary.

For a boundary width `delta`, sample:

```text
t_b ~ Uniform({max(0, t_zeta - delta), ..., min(T - 1, t_zeta + delta)})
```

Let `h_j^ell` and `h_s^ell` be hidden features from the same layer family `ell` in junior and senior.
Because junior and senior can have different channel widths, the alignment uses a channel-invariant feature signature:

```text
phi(h) = normalize(concat(mean_channel(h), std_channel(h)))
L_FA = E || phi(h_j^ell) - stopgrad(phi(h_s^ell)) ||_2^2
L_total = L_CST + lambda_FA * L_FA
```

Default alignment locations:

```text
LDM / SD: U-Net middle block and last decoder/up block signatures.
DiT: final transformer block token signature.
Fallback: denoiser output signature if a hook location is unavailable.
```

Meaning:

- FA does not train the senior model in the default CDF setting.
- FA only acts around the transition boundary, not across every timestep.
- The signature avoids requiring equal hidden dimensions across model scales.

### 3.5 Senior-Only Fine-Tuning

This baseline freezes the junior model and only trains the senior model on the senior interval.

```text
t_zeta = floor((1 - r0) * T)
t ~ Uniform({0, ..., t_zeta - 1})
L_senior_only(r0) = E || eps - eps_s(x_t, t, y) ||_2^2
```

Meaning:

- Tests whether improving the large/refinement part alone explains gains.
- This is not the default CDF deployment strategy.

### 3.6 Full Model Group Training

FMGT jointly trains junior and senior in their assigned intervals.

```text
t_zeta = floor((1 - r0) * T)
t_j ~ Uniform({t_zeta, ..., T - 1})
t_s ~ Uniform({0, ..., t_zeta - 1})
L_FMGT = E || eps - eps_j(x_tj, t_j, y) ||_2^2
       + E || eps - eps_s(x_ts, t_s, y) ||_2^2
```

Meaning:

- This is the high-cost joint-training baseline.
- It is less deployment-friendly because both checkpoints are updated.

## 4. Main LDM Experiments

Main setting:

```text
Dataset: ImageNet 256x256
Junior: LDM-S
Senior: LDM
Batch size: 64
Learning rate: 1e-5
DDPM training timesteps: T = 1000
Evaluation samples: 5000
Evaluation metrics: FID, IS, latency, speedup
Sampler: DDIM 100 steps unless specified
CFG scale: 3.0
Hardware report target: one RTX 4090 or the exact GPU used
```

Resume behavior:

- LDM training writes `checkpoints/last.ckpt` with model, optimizer, scheduler, epoch, global step, and callback state.
- Resume one interrupted run at a time. For fixed-ratio jobs, pass a single ratio matching the checkpoint directory.
- Resume checks the checkpoint optimizer LR against the current effective LR and fails by default on mismatch.

```bash
bash run_cdf_experiments.sh ldm-train-fmgt \
  --ratios 0.1 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/fmgt \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5 \
  --resume logs/cdf/ldm/fmgt/ratio-0.1/<run_name>/checkpoints/last.ckpt
```

Only use this when intentionally changing LR after resume:

```bash
--allow-lr-mismatch true
```

### 4.1 NFT / T-Stitch Baseline

No training. Directly evaluate the existing pretrained junior and senior checkpoints.

```bash
bash run_cdf_experiments.sh ldm-eval-nft \
  --ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --num-fid-samples 5000 \
  --num-sampling-steps 100 \
  --cfg-scale 3.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/nft
```

Expected output:

```text
outputs/cdf/ldm/nft/samples/ratio-0.5.npz
outputs/cdf/ldm/nft/metrics.csv
```

### 4.2 FRFT Baseline

Train one junior checkpoint per ratio.

```bash
bash run_cdf_experiments.sh ldm-train-frft \
  --ratios 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/frft \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate all FRFT checkpoints on all ratios to measure cross-ratio generalization:

```bash
bash run_cdf_experiments.sh ldm-eval-frft \
  --checkpoint-dir logs/cdf/ldm/frft \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/frft
```

Expected output:

```text
outputs/cdf/ldm/frft/cross_ratio_metrics.csv
```

### 4.3 Senior-Only Baseline

Freeze junior, train senior on the senior interval for each fixed ratio.

```bash
bash run_cdf_experiments.sh ldm-train-senior-only \
  --ratios 0.1,0.3,0.5,0.7,0.9 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/senior_only \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh ldm-eval-senior-only \
  --checkpoint-dir logs/cdf/ldm/senior_only \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/senior_only
```

### 4.4 FMGT Baseline

Jointly train junior and senior.

```bash
bash run_cdf_experiments.sh ldm-train-fmgt \
  --ratios 0.1,0.3,0.5,0.7,0.9 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/fmgt \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh ldm-eval-fmgt \
  --checkpoint-dir logs/cdf/ldm/fmgt \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/fmgt
```

### 4.5 CST Main Run

Train one junior checkpoint with a progressive curriculum.

```bash
bash run_cdf_experiments.sh ldm-train-cst \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/cst_cosine \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate the one CST checkpoint at all ratios:

```bash
bash run_cdf_experiments.sh ldm-eval-cst \
  --checkpoint logs/cdf/ldm/cst_cosine/checkpoints/last.ckpt \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/cst_cosine
```

### 4.6 CST Schedule Ablation

Run several curriculum schedules with all other settings fixed.

```bash
bash run_cdf_experiments.sh ldm-train-cst-ablation \
  --schedule linear,cosine,cst_v1,cst_v2,staircase \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/schedule_ablation \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh ldm-eval-cst-ablation \
  --checkpoint-dir logs/cdf/ldm/schedule_ablation \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/schedule_ablation
```

### 4.7 CST + Feature Alignment

Train one junior checkpoint with curriculum and boundary feature alignment.

```bash
bash run_cdf_experiments.sh ldm-train-cst-fa \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --fa-weight 0.1 \
  --fa-boundary-width 10 \
  --data-root <imagenet_train> \
  --logdir logs/cdf/ldm/cst_cosine_fa \
  --max-steps 200000 \
  --batch-size 64 \
  --num-workers 0 \
  --scale-lr false \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh ldm-eval-cst-fa \
  --checkpoint logs/cdf/ldm/cst_cosine_fa/checkpoints/last.ckpt \
  --eval-ratios 0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 \
  --ref-batch <adm_imagenet_ref.npz> \
  --output-dir outputs/cdf/ldm/cst_cosine_fa
```

## 5. DiT Experiments

Purpose:

- Provide quantitative evidence beyond LDM.
- Explicitly connect NFT to T-Stitch under the same DiT samplers.
- Report FID, IS, latency, and speedup for all ratios.

Default DiT setting:

```text
Dataset: ImageNet 256x256
Junior: DiT-S/2
Senior: DiT-XL/2
Optional medium: DiT-B/2
Sampler: DDIM 100, plus DDPM and DPM-Solver++ ablations
CFG scale: 1.5
Evaluation samples: 5000
```

### 5.1 DiT NFT / T-Stitch

```bash
bash run_cdf_experiments.sh dit-eval-nft \
  --small-model DiT-S/2 \
  --large-model DiT-XL/2 \
  --solver ddim \
  --num-sampling-steps 100 \
  --cfg-scale 1.5 \
  --num-fid-samples 5000 \
  --ref-batch <adm_imagenet_ref.npz> \
  --vae-model <local_sd_vae_ft_ema_or_hf_id> \
  --output-dir outputs/cdf/dit/nft_ddim100
```

### 5.2 DiT FRFT

```bash
bash run_cdf_experiments.sh dit-train-frft \
  --ratios 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9 \
  --data-path <imagenet_train> \
  --small-model DiT-S/2 \
  --large-model DiT-XL/2 \
  --logdir logs/cdf/dit/frft \
  --epochs 1400 \
  --global-batch-size 256 \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh dit-eval-frft \
  --checkpoint-dir logs/cdf/dit/frft \
  --solver ddim \
  --num-sampling-steps 100 \
  --ref-batch <adm_imagenet_ref.npz> \
  --vae-model <local_sd_vae_ft_ema_or_hf_id> \
  --output-dir outputs/cdf/dit/frft
```

### 5.3 DiT CST and CST + FA

```bash
bash run_cdf_experiments.sh dit-train-cst \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --data-path <imagenet_train> \
  --small-model DiT-S/2 \
  --large-model DiT-XL/2 \
  --logdir logs/cdf/dit/cst_cosine \
  --epochs 1400 \
  --global-batch-size 256 \
  --learning-rate 1e-5

bash run_cdf_experiments.sh dit-train-cst-fa \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --fa-weight 0.1 \
  --fa-boundary-width 10 \
  --data-path <imagenet_train> \
  --small-model DiT-S/2 \
  --large-model DiT-XL/2 \
  --logdir logs/cdf/dit/cst_cosine_fa \
  --epochs 1400 \
  --global-batch-size 256 \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh dit-eval-cst \
  --checkpoint logs/cdf/dit/cst_cosine/checkpoints/last.pt \
  --solver ddim \
  --num-sampling-steps 100 \
  --ref-batch <adm_imagenet_ref.npz> \
  --vae-model <local_sd_vae_ft_ema_or_hf_id> \
  --output-dir outputs/cdf/dit/cst_cosine
```

### 5.4 DiT Sampler Ablation

```bash
for solver in ddpm ddim dpm-solver++; do
  bash run_cdf_experiments.sh dit-eval-cst \
    --checkpoint logs/cdf/dit/cst_cosine/checkpoints/last.pt \
    --solver "$solver" \
    --num-sampling-steps 50 \
    --ref-batch <adm_imagenet_ref.npz> \
    --vae-model <local_sd_vae_ft_ema_or_hf_id> \
    --output-dir outputs/cdf/dit/cst_cosine_${solver}_50
done
```

## 6. Stable Diffusion / Text-to-Image Experiments

Purpose:

- Address general text-to-image prompts beyond ImageNet.
- Report FID, IS, and CLIP score on MS-COCO.
- Test orthogonality with DeepCache.

Default SD setting:

```text
Dataset/prompts: MS-COCO validation captions
Junior: BK-SDM Tiny
Senior: SD v1.4 or stylized SD
Sampler: PNDM 50 steps
Guidance scale: 7.5
Resolution: 256x256 for Table 2-style metrics
Evaluation samples: 5000
```

### 6.1 SD NFT / T-Stitch on COCO

```bash
bash run_cdf_experiments.sh sd-eval-nft \
  --prompts <captions_val2014.json> \
  --ref-batch <coco_ref_batch.npz> \
  --output-dir outputs/cdf/sd/nft \
  --limit 5000
```

### 6.2 SD CST / CST + FA

```bash
bash run_cdf_experiments.sh sd-train-cst \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --train-data-dir <image_text_train_dir> \
  --metadata-file <metadata.jsonl> \
  --output-dir logs/cdf/sd/cst_cosine \
  --max-train-steps 100000 \
  --train-batch-size 1 \
  --learning-rate 1e-5

bash run_cdf_experiments.sh sd-train-cst-fa \
  --schedule cosine \
  --ratio-start 0.1 \
  --ratio-end 0.9 \
  --fa-weight 0.1 \
  --fa-boundary-width 2 \
  --train-data-dir <image_text_train_dir> \
  --metadata-file <metadata.jsonl> \
  --output-dir logs/cdf/sd/cst_cosine_fa \
  --max-train-steps 100000 \
  --train-batch-size 1 \
  --learning-rate 1e-5
```

Evaluate:

```bash
bash run_cdf_experiments.sh sd-eval-cst \
  --checkpoint logs/cdf/sd/cst_cosine \
  --prompts <captions_val2014.json> \
  --ref-batch <coco_ref_batch.npz> \
  --output-dir outputs/cdf/sd/cst_cosine \
  --limit 5000
```

### 6.3 SD + DeepCache Orthogonal Experiment

Compare:

```text
SD NFT
SD NFT + DeepCache
SD CDF/CST
SD CDF/CST + DeepCache
```

Run:

```bash
bash run_cdf_experiments.sh sd-eval-deepcache \
  --checkpoint logs/cdf/sd/cst_cosine \
  --prompts <captions_val2014.json> \
  --ref-batch <coco_ref_batch.npz> \
  --deepcache-interval 3 \
  --output-dir outputs/cdf/sd/cst_cosine_deepcache \
  --limit 5000
```

Metrics:

```text
FID, IS, CLIP score, latency, speedup
```

## 7. Data Products for Paper Figures

The final implementation should export the following CSV files.

```text
Figure 1: outputs/cdf/ldm/main_tradeoff.csv
  columns: method, ratio, fid, is, latency_sec, speedup, checkpoint

Figure 3: outputs/cdf/training_cost.csv
  columns: method, num_checkpoints, trainable_params, gpu_days, supported_ratios

Figure 4: outputs/cdf/ldm/cross_ratio_generalization.csv
  columns: train_method, train_ratio, eval_ratio, fid, is

Figure 5: outputs/cdf/ldm/cst_convergence.csv
  columns: epoch_or_step, ratio, fid, is

Figure 6: outputs/cdf/ldm/schedule_fa_ablation.csv
  columns: method, schedule, fa_weight, ratio, fid, is, latency_sec

Figure 7: outputs/cdf/efficiency_by_arch_sampler.csv
  columns: arch, sampler, num_steps, ratio, latency_sec, speedup

Figure 8: outputs/cdf/sd/deepcache_compatibility.csv
  columns: method, ratio, fid, kid, is, clip_score, latency_sec
```

## 8. Implementation Checklist

The current repository already has partial T-Stitch training and sampling.
The following items must be implemented or verified before the commands above are considered runnable end-to-end:

- Add explicit `train_mode` values: `junior`, `senior`, `joint`.
- Add exact schedule functions: `fixed`, `linear`, `cosine`, `cst_v1`, `cst_v2`, `staircase`.
- Sample training timesteps from the correct interval for each training mode.
- Add boundary Feature Alignment with documented layer hooks and output fallback.
- Add LDM runner commands for NFT, FRFT, senior-only, FMGT, CST, CST+FA.
- Add all-ratio evaluation that emits `.npz` samples and `metrics.csv`.
- Align DiT training flags with the same CDF names and schedules.
- Align SD/SDXL training flags with the same CDF names and schedules.
- Add COCO prompt generation, CLIP score, FID/IS aggregation, and DeepCache toggles to the CDF runner.