notes/episode_task_suite.md

Episode Task Suite

Script:

scripts/episode_task_suite.py

This script turns the single public Xperience-10M sample episode into many end-to-end tasks. It is designed for learning, debugging, and task design. It is not a generalization benchmark because the data is still one episode.

Run:

cd /path/to/Ropedia
source .venv/bin/activate
python scripts/episode_task_suite.py

Output:

outputs/episode_task_suite/

Shared setup:

sample episode: 5821 frames
windows:        1161
window size:    20 frames
stride:         5 frames
feature dim:    8546
split:          chronological, first 70% train and last 30% test

Implemented Tasks

Task	Input	Output	Main artifact
timeline_action	all modality window	current action label	timeline_action/metrics.json
timeline_subtask	all modality window	current subtask label	timeline_subtask/metrics.json
transition_detection	all modality window	steady vs action boundary	transition_detection/metrics.json
next_action	current all modality window	action 20 frames later	next_action/metrics.json
hand_trajectory_forecast	current all modality window	future 10-frame left/right hand joints	hand_trajectory_forecast/predictions.npz
contact_prediction	non-contact modalities	any body contact in window	contact_prediction/metrics.json
object_relevance	non-caption modalities	relevant object set	object_relevance/predictions.csv
caption_grounding	caption objects/interaction query + sensor candidates	matching time window	caption_grounding/metrics.json
cross_modal_retrieval	motion/IMU/camera/audio query	matching depth/video window	cross_modal_retrieval/metrics.json
modality_reconstruction	motion/IMU/camera/audio	depth/video feature vector	modality_reconstruction/predictions.npz
temporal_order	two adjacent windows	whether order is correct	temporal_order/metrics.json
misalignment_detection	motion+visual/audio pair	aligned vs shifted	misalignment_detection/metrics.json

Minimal Model Architectures

All tasks share the same window builder unless a task explicitly removes a feature block to avoid label leakage.

raw sample episode
  -> 20-frame sliding windows, stride 5
  -> all-modality feature vector X_all, 8,546 dimensions
  -> chronological split, first 70% train and last 30% test
  -> train-only z-score scaler
  -> task-specific minimal head

The task suite intentionally uses simple heads:

Family	Formula	Tasks
Linear softmax	softmax(z(X)W + b), cross-entropy, L2	timeline_action, timeline_subtask, transition_detection, next_action, contact_prediction, temporal_order, misalignment_detection
Ridge regression/projection	dual ridge regression with L2=10 on z-scored X/Y	hand_trajectory_forecast, caption_grounding, cross_modal_retrieval, modality_reconstruction
Multi-label logistic	sigmoid(z(X)W + b), weighted object heads	object_relevance

Task-specific architecture details:

Task	Input tensor/vector	Minimal head	Output target
timeline_action	X_all, 8,546d	class-weighted linear softmax	current action label
timeline_subtask	X_all, 8,546d	class-weighted linear softmax	current subtask label
transition_detection	X_all, 8,546d	class-weighted linear softmax	steady vs transition near action boundary
next_action	X_all(t), 8,546d	class-weighted linear softmax	action at t+20 frames
hand_trajectory_forecast	X_all(t), 8,546d	ridge regression	future 10 frames of left/right hand joints, 1,260d
contact_prediction	all features except body_contacts and caption text, 7,503d	linear softmax on observed labels	any body contact in window
object_relevance	all features except caption text, 7,650d	multi-label logistic regression	34-object multi-hot vector
caption_grounding	sensor features, 7,650d, projected into 896d text space	ridge projection plus cosine ranking	matching time window for a text query
cross_modal_retrieval	motion/IMU/camera/audio, 2,415d, projected into 5,096d visual space	ridge projection plus cosine ranking	matching depth/video window
modality_reconstruction	motion/IMU/camera/audio, 2,415d	ridge regression	depth/video feature vector, 5,096d
temporal_order	[x_t, x_t+1, x_t+1-x_t], 25,638d	binary linear softmax	correct vs reversed order
misalignment_detection	motion plus visual/audio pair, 7,511d	binary linear softmax	aligned vs shifted by 8 windows

Diagram:

docs/assets/task_architectures.png

Neural Baseline

The suite can also run a lightweight PyTorch MLP baseline for every selected task while preserving the NumPy baseline artifacts:

python scripts/episode_task_suite.py \
  --output-dir results/episode_task_suite \
  --include-neural

This requires torch; use requirements-omni.txt when the base environment does not already include PyTorch.

The neural path reuses the same windows, features, chronological split, leakage filters, and metrics as the minimal heads. It writes parallel artifacts under:

results/episode_task_suite/neural_mlp/<task>/

Each neural task directory contains metrics.json, history.json, a model.pt checkpoint, and the same prediction artifact shape used by the corresponding minimal task (predictions.csv or predictions.npz). The suite rollup adds a neural_tasks section to summary_report.json; visualization generation adds neural-only and minimal-vs-neural score charts when those metrics are present.

Useful knobs:

python scripts/episode_task_suite.py \
  --include-neural \
  --neural-epochs 80 \
  --neural-hidden-dim 128 \
  --neural-batch-size 128 \
  --neural-device auto

This neural baseline is intentionally small. It tests whether a nonlinear head over the current handcrafted feature vector improves per-task behavior before moving to heavier sequence or vision-language models.

Qwen/Omni Neural Track

The Qwen3-Omni scripts remain a separate neural/VLM track under scripts/omni/. They are better suited for action/subtask adapter checks, sensor-adapter experiments, and LoRA fine-tuning than for the full 12-task matrix. A useful comparison order is:

• current NumPy task suite
• lightweight neural_mlp task suite
• adapter-only setup checks from scripts/omni/qwen3_omni_adapter_smoke.py
• Qwen3-Omni zero-shot or LoRA runs where GPU/model access is available

Current Results

timeline_action:
  accuracy: 0.0292
  macro_f1: 0.0500
  note: future test region contains unseen action classes

timeline_subtask:
  accuracy: 0.0581
  macro_f1: 0.0506
  note: future test region contains unseen subtask classes

transition_detection:
  accuracy: 0.9080
  macro_f1: 0.6118
  boundary_f1: 0.1250

next_action:
  accuracy: 0.0345
  macro_f1: 0.0593
  note: same unseen-future-class problem as timeline_action

hand_trajectory_forecast:
  MPJPE: 0.8647
  final-frame MPJPE: 1.0331

contact_prediction:
  accuracy: 1.0000
  note: degenerate on this sample because the binary contact label has only one class

object_relevance:
  micro_f1: 0.1803
  macro_f1: 0.0633

caption_grounding:
  top1: 0.0029
  top5: 0.0115
  MRR: 0.0160

cross_modal_retrieval:
  top1: 0.1638
  top5: 0.3678
  top10: 0.4713
  MRR: 0.2693

modality_reconstruction:
  R2: -0.0153

temporal_order:
  accuracy: 0.4540
  f1: 0.5400

misalignment_detection:
  accuracy: 0.5159
  f1: 0.5052

How To Read These Results

Low scores are useful here. They show which tasks are not learnable from this one chronological sample with this minimal model.

The strongest signal is cross_modal_retrieval: motion/IMU/camera/audio features can retrieve the matching depth/video window better than random. That means the modalities are synchronized and contain shared temporal structure.

The weakest supervised timeline tasks are weak mainly because of the split. The last 30% of a single ordered episode contains actions/subtasks not present in the first 70%, so a classifier trained on the first part cannot predict labels it never saw.

For serious research, keep the same task code but change the dataset unit:

many episodes -> train episodes -> test unseen episodes

For single-episode learning, these tasks are best used as:

• data pipeline tests
• modality ablations
• label-alignment checks
• self-supervised retrieval experiments
• debugging templates before scaling to many episodes