Files
ai_mouse/tools/export_onnx.py

306 lines
9.5 KiB
Python

"""Export trained PyTorch checkpoints to ONNX for the inference SDK.
Usage:
uv run python -m tools.export_onnx \
--flow-ckpt data/models_v2 \
--scroll-ckpt data/scroll_models \
--output src/ai_mouse/assets/
Produces:
<output>/flow_model.onnx
<output>/scroll_decoder.onnx
<output>/click_dist.json
<output>/duration_dist.json
<output>/train_config.json
<output>/scroll_config.json
A PyTorch vs ONNX Runtime parity check runs at the end. If parity fails
the .onnx files are deleted to prevent shipping broken weights.
"""
from __future__ import annotations
import argparse
import json
import logging
import shutil
import sys
from pathlib import Path
import numpy as np
import torch
logger = logging.getLogger(__name__)
_ATOL = 1e-4
def export_flow_model(ckpt_dir: Path, out_dir: Path) -> Path:
"""Export TrajectoryFlowModel to ONNX.
Args:
ckpt_dir: directory with flow_model.pt and train_config.json.
out_dir: destination directory (created if missing).
Returns:
Path to the written flow_model.onnx.
"""
from tools.models import TrajectoryFlowModel
config_path = ckpt_dir / "train_config.json"
cfg = json.loads(config_path.read_text())
seq_len = int(cfg["seq_len"])
d_model = int(cfg["d_model"])
nhead = int(cfg["nhead"])
num_layers = int(cfg["num_layers"])
dim_feedforward = int(cfg["dim_feedforward"])
cond_dim = int(cfg.get("cond_dim", 3))
model = TrajectoryFlowModel(
seq_len=seq_len,
d_model=d_model,
nhead=nhead,
num_layers=num_layers,
dim_feedforward=dim_feedforward,
cond_dim=cond_dim,
dropout=0.0,
)
state = torch.load(ckpt_dir / "flow_model.pt", map_location="cpu", weights_only=True)
model.load_state_dict(state)
model.eval()
out_dir.mkdir(parents=True, exist_ok=True)
out_path = out_dir / "flow_model.onnx"
dummy_x = torch.zeros(1, seq_len, 3, dtype=torch.float32)
dummy_t = torch.zeros(1, dtype=torch.float32)
dummy_cond = torch.zeros(1, cond_dim, dtype=torch.float32)
torch.onnx.export(
model,
(dummy_x, dummy_t, dummy_cond),
str(out_path),
input_names=["x_t", "t", "cond"],
output_names=["v"],
dynamic_axes={
"x_t": {0: "batch"},
"t": {0: "batch"},
"cond": {0: "batch"},
"v": {0: "batch"},
},
opset_version=17,
do_constant_folding=True,
dynamo=False,
)
logger.info("Wrote %s (%.1f MB)", out_path, out_path.stat().st_size / 1e6)
return out_path
class _ScrollDecoder(torch.nn.Module):
"""Wraps ScrollCVAE.decode for ONNX export.
The full ScrollCVAE is encoder+decoder; inference only needs decoder.
"""
def __init__(self, dec_h0, dec_gru, dec_out, seq_len: int, hidden: int):
super().__init__()
self.dec_h0 = dec_h0
self.dec_gru = dec_gru
self.dec_out = dec_out
self.seq_len = seq_len
self.hidden = hidden
def forward(self, z: torch.Tensor, cond: torch.Tensor) -> torch.Tensor:
b = z.shape[0]
zc = torch.cat([z, cond], dim=-1)
h0_flat = self.dec_h0(zc)
h0 = h0_flat.view(b, 2, self.hidden).permute(1, 0, 2).contiguous()
inp = zc.unsqueeze(1).expand(b, self.seq_len, -1)
out, _ = self.dec_gru(inp, h0)
return self.dec_out(out)
def export_scroll_decoder(ckpt_dir: Path, out_dir: Path) -> Path:
"""Export ScrollCVAE decoder to ONNX."""
from tools.scroll.models import ScrollCVAE
config_path = ckpt_dir / "scroll_config.json"
cfg = json.loads(config_path.read_text())
seq_len = int(cfg["seq_len"])
latent_dim = int(cfg["latent_dim"])
hidden = int(cfg["hidden"])
cond_dim = int(cfg["cond_dim"])
full = ScrollCVAE(
seq_len=seq_len, latent_dim=latent_dim, hidden=hidden, cond_dim=cond_dim
)
state = torch.load(ckpt_dir / "scroll_model.pt", map_location="cpu", weights_only=True)
full.load_state_dict(state)
full.eval()
decoder = _ScrollDecoder(
dec_h0=full.dec_h0,
dec_gru=full.dec_gru,
dec_out=full.dec_out,
seq_len=seq_len,
hidden=hidden,
)
decoder.eval()
out_dir.mkdir(parents=True, exist_ok=True)
out_path = out_dir / "scroll_decoder.onnx"
dummy_z = torch.zeros(1, latent_dim, dtype=torch.float32)
dummy_cond = torch.zeros(1, cond_dim, dtype=torch.float32)
torch.onnx.export(
decoder,
(dummy_z, dummy_cond),
str(out_path),
input_names=["z", "cond"],
output_names=["seq"],
dynamic_axes={
"z": {0: "batch"},
"cond": {0: "batch"},
"seq": {0: "batch"},
},
opset_version=17,
do_constant_folding=True,
dynamo=False,
)
logger.info("Wrote %s (%.1f KB)", out_path, out_path.stat().st_size / 1e3)
return out_path
def _check_flow_parity(ckpt_dir: Path, onnx_path: Path) -> None:
"""Verify ONNX flow model matches PyTorch output on random input."""
import onnxruntime as ort
from tools.models import TrajectoryFlowModel
cfg = json.loads((ckpt_dir / "train_config.json").read_text())
seq_len = int(cfg["seq_len"])
cond_dim = int(cfg.get("cond_dim", 3))
model = TrajectoryFlowModel(
seq_len=seq_len,
d_model=int(cfg["d_model"]),
nhead=int(cfg["nhead"]),
num_layers=int(cfg["num_layers"]),
dim_feedforward=int(cfg["dim_feedforward"]),
cond_dim=cond_dim,
dropout=0.0,
)
model.load_state_dict(
torch.load(ckpt_dir / "flow_model.pt", map_location="cpu", weights_only=True)
)
model.eval()
torch.manual_seed(42)
np.random.seed(42)
x = torch.randn(2, seq_len, 3, dtype=torch.float32)
t = torch.tensor([0.0, 0.5], dtype=torch.float32)
cond = torch.randn(2, cond_dim, dtype=torch.float32)
with torch.no_grad():
torch_out = model(x, t, cond).numpy()
sess = ort.InferenceSession(str(onnx_path), providers=["CPUExecutionProvider"])
ort_out = sess.run(
["v"],
{
"x_t": x.numpy(),
"t": t.numpy(),
"cond": cond.numpy(),
},
)[0]
if not np.allclose(torch_out, ort_out, atol=_ATOL, rtol=1e-3):
max_diff = float(np.abs(torch_out - ort_out).max())
raise RuntimeError(
f"Flow model ORT/PyTorch parity FAILED: max abs diff = {max_diff:.2e} > {_ATOL:.2e}"
)
logger.info("Flow model parity OK (atol=%.0e)", _ATOL)
def _check_scroll_parity(ckpt_dir: Path, onnx_path: Path) -> None:
"""Verify ONNX scroll decoder matches PyTorch decoder output."""
import onnxruntime as ort
from tools.scroll.models import ScrollCVAE
cfg = json.loads((ckpt_dir / "scroll_config.json").read_text())
seq_len = int(cfg["seq_len"])
latent_dim = int(cfg["latent_dim"])
cond_dim = int(cfg["cond_dim"])
full = ScrollCVAE(
seq_len=seq_len,
latent_dim=latent_dim,
hidden=int(cfg["hidden"]),
cond_dim=cond_dim,
)
full.load_state_dict(
torch.load(ckpt_dir / "scroll_model.pt", map_location="cpu", weights_only=True)
)
full.eval()
torch.manual_seed(7)
z = torch.randn(2, latent_dim, dtype=torch.float32)
cond = torch.randn(2, cond_dim, dtype=torch.float32)
with torch.no_grad():
torch_out = full.decode(z, cond).numpy()
sess = ort.InferenceSession(str(onnx_path), providers=["CPUExecutionProvider"])
ort_out = sess.run(["seq"], {"z": z.numpy(), "cond": cond.numpy()})[0]
if not np.allclose(torch_out, ort_out, atol=_ATOL, rtol=1e-3):
max_diff = float(np.abs(torch_out - ort_out).max())
raise RuntimeError(
f"Scroll decoder parity FAILED: max abs diff = {max_diff:.2e} > {_ATOL:.2e}"
)
logger.info("Scroll decoder parity OK (atol=%.0e)", _ATOL)
def _copy_metadata(flow_dir: Path, scroll_dir: Path, out_dir: Path) -> None:
"""Copy JSON metadata files alongside the ONNX models."""
for name in ("click_dist.json", "duration_dist.json", "train_config.json"):
src = flow_dir / name
if not src.exists():
raise FileNotFoundError(f"Required metadata missing: {src}")
shutil.copy2(src, out_dir / name)
src = scroll_dir / "scroll_config.json"
if not src.exists():
raise FileNotFoundError(f"Required metadata missing: {src}")
shutil.copy2(src, out_dir / "scroll_config.json")
def main(argv: list[str] | None = None) -> int:
p = argparse.ArgumentParser(prog="export_onnx", description=__doc__.splitlines()[0])
p.add_argument("--flow-ckpt", type=Path, required=True)
p.add_argument("--scroll-ckpt", type=Path, required=True)
p.add_argument("--output", type=Path, required=True)
args = p.parse_args(argv)
logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(message)s")
args.output.mkdir(parents=True, exist_ok=True)
flow_onnx = export_flow_model(args.flow_ckpt, args.output)
scroll_onnx = export_scroll_decoder(args.scroll_ckpt, args.output)
try:
_check_flow_parity(args.flow_ckpt, flow_onnx)
_check_scroll_parity(args.scroll_ckpt, scroll_onnx)
except RuntimeError as exc:
logger.error("Parity check failed: %s", exc)
flow_onnx.unlink(missing_ok=True)
scroll_onnx.unlink(missing_ok=True)
return 1
_copy_metadata(args.flow_ckpt, args.scroll_ckpt, args.output)
logger.info("Export complete: %s", args.output)
return 0
if __name__ == "__main__":
sys.exit(main())