in scripts/convert_stable_diffusion_checkpoint_to_onnx.py [0:0]
def convert_models(model_path: str, output_path: str, opset: int, fp16: bool = False):
dtype = torch.float16 if fp16 else torch.float32
if fp16 and torch.cuda.is_available():
device = "cuda"
elif fp16 and not torch.cuda.is_available():
raise ValueError("`float16` model export is only supported on GPUs with CUDA")
else:
device = "cpu"
pipeline = StableDiffusionPipeline.from_pretrained(model_path, torch_dtype=dtype).to(device)
output_path = Path(output_path)
# TEXT ENCODER
num_tokens = pipeline.text_encoder.config.max_position_embeddings
text_hidden_size = pipeline.text_encoder.config.hidden_size
text_input = pipeline.tokenizer(
"A sample prompt",
padding="max_length",
max_length=pipeline.tokenizer.model_max_length,
truncation=True,
return_tensors="pt",
)
onnx_export(
pipeline.text_encoder,
# casting to torch.int32 until the CLIP fix is released: https://github.com/huggingface/transformers/pull/18515/files
model_args=(text_input.input_ids.to(device=device, dtype=torch.int32)),
output_path=output_path / "text_encoder" / "model.onnx",
ordered_input_names=["input_ids"],
output_names=["last_hidden_state", "pooler_output"],
dynamic_axes={
"input_ids": {0: "batch", 1: "sequence"},
},
opset=opset,
)
del pipeline.text_encoder
# UNET
unet_in_channels = pipeline.unet.config.in_channels
unet_sample_size = pipeline.unet.config.sample_size
unet_path = output_path / "unet" / "model.onnx"
onnx_export(
pipeline.unet,
model_args=(
torch.randn(2, unet_in_channels, unet_sample_size, unet_sample_size).to(device=device, dtype=dtype),
torch.randn(2).to(device=device, dtype=dtype),
torch.randn(2, num_tokens, text_hidden_size).to(device=device, dtype=dtype),
False,
),
output_path=unet_path,
ordered_input_names=["sample", "timestep", "encoder_hidden_states", "return_dict"],
output_names=["out_sample"], # has to be different from "sample" for correct tracing
dynamic_axes={
"sample": {0: "batch", 1: "channels", 2: "height", 3: "width"},
"timestep": {0: "batch"},
"encoder_hidden_states": {0: "batch", 1: "sequence"},
},
opset=opset,
use_external_data_format=True, # UNet is > 2GB, so the weights need to be split
)
unet_model_path = str(unet_path.absolute().as_posix())
unet_dir = os.path.dirname(unet_model_path)
unet = onnx.load(unet_model_path)
# clean up existing tensor files
shutil.rmtree(unet_dir)
os.mkdir(unet_dir)
# collate external tensor files into one
onnx.save_model(
unet,
unet_model_path,
save_as_external_data=True,
all_tensors_to_one_file=True,
location="weights.pb",
convert_attribute=False,
)
del pipeline.unet
# VAE ENCODER
vae_encoder = pipeline.vae
vae_in_channels = vae_encoder.config.in_channels
vae_sample_size = vae_encoder.config.sample_size
# need to get the raw tensor output (sample) from the encoder
vae_encoder.forward = lambda sample, return_dict: vae_encoder.encode(sample, return_dict)[0].sample()
onnx_export(
vae_encoder,
model_args=(
torch.randn(1, vae_in_channels, vae_sample_size, vae_sample_size).to(device=device, dtype=dtype),
False,
),
output_path=output_path / "vae_encoder" / "model.onnx",
ordered_input_names=["sample", "return_dict"],
output_names=["latent_sample"],
dynamic_axes={
"sample": {0: "batch", 1: "channels", 2: "height", 3: "width"},
},
opset=opset,
)
# VAE DECODER
vae_decoder = pipeline.vae
vae_latent_channels = vae_decoder.config.latent_channels
vae_out_channels = vae_decoder.config.out_channels
# forward only through the decoder part
vae_decoder.forward = vae_encoder.decode
onnx_export(
vae_decoder,
model_args=(
torch.randn(1, vae_latent_channels, unet_sample_size, unet_sample_size).to(device=device, dtype=dtype),
False,
),
output_path=output_path / "vae_decoder" / "model.onnx",
ordered_input_names=["latent_sample", "return_dict"],
output_names=["sample"],
dynamic_axes={
"latent_sample": {0: "batch", 1: "channels", 2: "height", 3: "width"},
},
opset=opset,
)
del pipeline.vae
# SAFETY CHECKER
if pipeline.safety_checker is not None:
safety_checker = pipeline.safety_checker
clip_num_channels = safety_checker.config.vision_config.num_channels
clip_image_size = safety_checker.config.vision_config.image_size
safety_checker.forward = safety_checker.forward_onnx
onnx_export(
pipeline.safety_checker,
model_args=(
torch.randn(
1,
clip_num_channels,
clip_image_size,
clip_image_size,
).to(device=device, dtype=dtype),
torch.randn(1, vae_sample_size, vae_sample_size, vae_out_channels).to(device=device, dtype=dtype),
),
output_path=output_path / "safety_checker" / "model.onnx",
ordered_input_names=["clip_input", "images"],
output_names=["out_images", "has_nsfw_concepts"],
dynamic_axes={
"clip_input": {0: "batch", 1: "channels", 2: "height", 3: "width"},
"images": {0: "batch", 1: "height", 2: "width", 3: "channels"},
},
opset=opset,
)
del pipeline.safety_checker
safety_checker = OnnxRuntimeModel.from_pretrained(output_path / "safety_checker")
feature_extractor = pipeline.feature_extractor
else:
safety_checker = None
feature_extractor = None
onnx_pipeline = OnnxStableDiffusionPipeline(
vae_encoder=OnnxRuntimeModel.from_pretrained(output_path / "vae_encoder"),
vae_decoder=OnnxRuntimeModel.from_pretrained(output_path / "vae_decoder"),
text_encoder=OnnxRuntimeModel.from_pretrained(output_path / "text_encoder"),
tokenizer=pipeline.tokenizer,
unet=OnnxRuntimeModel.from_pretrained(output_path / "unet"),
scheduler=pipeline.scheduler,
safety_checker=safety_checker,
feature_extractor=feature_extractor,
requires_safety_checker=safety_checker is not None,
)
onnx_pipeline.save_pretrained(output_path)
print("ONNX pipeline saved to", output_path)
del pipeline
del onnx_pipeline
_ = OnnxStableDiffusionPipeline.from_pretrained(output_path, provider="CPUExecutionProvider")
print("ONNX pipeline is loadable")