Expand an HDF5 recording by cloning trajectories with action/state noise. Use when asked to mimic, expand, or augment a dataset; not for recording new demos (use [[i4h-workflow-dataset-teleop]]).
Scanned 9/3/2026
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---
name: i4h-workflow-dataset-mimic
version: "0.6.0"
description: Expand an HDF5 recording by cloning trajectories with action/state noise. Use when asked to mimic, expand, or augment a dataset; not for recording new demos (use [[i4h-workflow-dataset-teleop]]).
license: Apache-2.0
metadata:
author: "Isaac for Healthcare Team <isaac-for-healthcare-support@nvidia.com>"
tags:
- isaac-for-healthcare
- i4h
- dataset
- mimic
- augmentation
---
# i4h Workflow — Mimic Dataset
## Purpose
Expand an HDF5 recording by replicating trajectories with small action and state noise. Use when the user asks to mimic, expand, or augment a dataset without recording new episodes. If the same prompt also asks to visualize the dataset, finish mimic first, then compose [[i4h-workflow-dataset-convert]] and [[i4h-lerobot-viz]] on the mimic output.
## Base Code
These steps drive the i4h-workflows base code (the `workflows/agentic/` tree). To reuse an existing checkout, set `I4H_WORKFLOWS` to its path (no clone happens). Otherwise this resolves the current repo, or clones to `~/i4h-workflows` — pick that default without prompting. Run every command below from the resolved root:
```bash
# Resolve the i4h-workflows base code (provides workflows/agentic/).
ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"
if [ ! -d "$ROOT/workflows/agentic" ]; then
ROOT="${I4H_WORKFLOWS:-$HOME/i4h-workflows}"
[ -d "$ROOT/workflows/agentic" ] || git clone https://github.com/isaac-for-healthcare/i4h-workflows "$ROOT"
fi
export I4H_WORKFLOWS="$ROOT"; cd "$ROOT"
```
## Basics
- **Env config (source of truth):** `workflows/agentic/config/environments/<env>.yaml` defines the `<env>` robot and task the mimicked trajectories replay against.
- Mimic perturbs action/state, not visuals.
- Default `--include-source` keeps the original demos in the output.
- In a chained workflow after teleop/validate, use the HDF5 produced by that chain. Do not silently fall back to an older same-env recording if the latest/current recording is empty or failed; stop and report that source demos are missing.
- Count HDF5 episodes with the workflow venv, not system Python (`h5py` may not be installed globally).
## Run
Run the steps below in order. Each step is a separate bash call; variables persist in the local agent's tmux session.
### Step 1 — setup and resolve input HDF5
```bash
REPO_ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"; [ -d "$REPO_ROOT/workflows/agentic" ] || REPO_ROOT="$HOME/i4h-workflows"
ENV_ID=scissor_pick_and_place
RUNS_ROOT="${REPO_ROOT}/workflows/agentic/runs"
# Point IN at a real recording to expand (absolute path). Recordings come from teleop or
# validate (which writes data/verify.hdf5 under each runs/eval_* dir). List candidates newest-first:
# find "${RUNS_ROOT}" -name '*.hdf5' -printf '%TY-%Tm-%Td %TH:%TM %p\n' | sort -r | head
IN="${IN:-}"
if [ ! -f "${IN}" ]; then
echo "mimic: set IN to an existing .hdf5 (got '${IN:-<unset>}'). Candidates:" >&2
find "${RUNS_ROOT}" -name '*.hdf5' -printf '%TY-%Tm-%Td %TH:%TM %p\n' 2>/dev/null | sort -r | head
exit 1
fi
# Verify the selected input is a real recording before mimic. A tiny HDF5 or
# `0/N episodes succeeded` teleop artifact is not usable source data.
"${REPO_ROOT}/workflows/agentic/mimic/.venv/bin/python" - "${IN}" <<'PY'
import h5py
import sys
path = sys.argv[1]
with h5py.File(path, "r") as f:
count = len(f["data"]) if "data" in f else 0
print(f"source episodes: {count}")
if count <= 0:
raise SystemExit("mimic: input HDF5 has no episodes; record successful demos first")
PY
RUN_DIR="${RUNS_ROOT}/mimic_${ENV_ID}_$(date +%Y%m%d_%H%M%S)"
mkdir -p "${RUN_DIR}/data" "${RUN_DIR}/logs"
ln -sfn "${RUN_DIR}" "${RUNS_ROOT}/.latest"
OUT="${RUN_DIR}/data/demo_mimic.hdf5"
```
When resolving "my dataset" from prior prompts, inspect candidates newest-first and prefer the current chain's latest successful teleop/validate HDF5. If the newest HDF5 for the target env has 0 episodes, do not skip back to an older run unless the user explicitly asks to reuse that older dataset.
### Step 2 — mimic expand
```bash
"${REPO_ROOT}/workflows/agentic/mimic/run.sh" --env "${ENV_ID}" \
--input "${IN}" \
--output "${OUT}" \
--episodes 3 \
--noise-std 0.01 \
--include-source \
--overwrite \
2>&1 | tee "${RUN_DIR}/logs/mimic.log"
```
## Verify
```bash
uv --directory "${REPO_ROOT}/workflows/agentic/mimic" run python -c \
"import h5py; print('episodes:', len(h5py.File('${OUT}','r')['data']))"
```
Confirm the output episode count equals the source demos plus `--episodes`.
Also confirm the input episode count was greater than zero; mimic output from an empty source is invalid.
If the prompt includes visualization (for example, "Mimic 3 more episodes and visualize my dataset"), continue after this verify step:
1. Load [[i4h-workflow-dataset-convert]] and set `HDF5_PATH="${OUT}"` so the augmented HDF5 is converted to LeRobot with `--video-codec h264`.
2. Load [[i4h-lerobot-viz]] and set `DATASET_DIR` to the converted dataset directory (`${HF_LEROBOT_HOME}/local/${ENV_ID}` by default).
3. Report both the augmented HDF5 and the visualizer URL.
## Prerequisites
- Workflow set up via [[i4h-workflow-setup]] (the `.venv` must exist).
- An existing input HDF5 recording (`--input`).
- The env id that produced the recording.
## Limitations
- Perturbs action/state only, not visuals.
- Augments an existing recording rather than recording new episodes.
- Output state/action dimensions must match the source.
## Troubleshooting
- **Error:** `.venv` not found / mimic fails to launch - Cause: workflow not set up. Fix: run [[i4h-workflow-setup]] first.
- **Error:** input recording not found - Cause: wrong or missing `--input` HDF5 path. Fix: point to the existing recording file.
- **Error:** input HDF5 has no episodes - Cause: teleop was launched but no successful episodes were saved. Fix: record successful source demos first; do not substitute an older run without explicit user direction.
- **Error:** output already exists / write refused - Cause: `--output` path is occupied. Fix: choose a new path or pass `--overwrite`.
- **Error:** state/action dimension mismatch on inspect - Cause: `--env` differs from the env that produced the input. Fix: use the same env id as the source recording.
## Final Response
Report input path, output path, generated episode count, noise std, whether source demos were included, and the visualizer URL if visualization was requested.
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