C++ Pipeline for Stable Diffusion v1.5 with Pybind for Lora Enabling

LoRA, or Low-Rank Adaptation, reduces the number of trainable parameters by learning pairs of rank-decompostion matrices while freezing the original weights. This vastly reduces the storage requirement for large language models adapted to specific tasks and enables efficient task-switching during deployment all without introducing inference latency. Thus for a basic large model, the task scenarios of the model can be changed by different LoRAs. In a previous blog, it has been described how to convert the LoRAs-fused base model from pytorch to OpenVINO IR, but this method has the shortcoming of not being able to dynamically switch between LoRAs, which happen to be famous for their flexibility.

This blog will introduce how to implement the dynamic switching of LoRAs in a trick way. Specifically, for most of the tasks, the structure of the base model and LoRAs is unchanged, what changes is the task-specific LoRAs weights, and we can use these LoRAs weights as inputs to the model to achieve the dynamic switching function. All the code involved in this blog can be found here.

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1. Environment preparation

# %python -m venv stable-diffusion-lora
# %source stable-diffusion-lora/bin/activate
git clone https://github.com/TianmengChen/sd1.5_controlnet_lora.git
pip install -r requirements.txt

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2. Convert and inference

you should first change the lora file path and configs at first around line 478 in ov_model_export.py, after run python ov_model_ export.py, you will get related OpenVINO IR model. Then you can run ov_model_infer.py.

python ov_model_export.py
python ov_model_infer.py

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3. Codes explanation

The most important part is the code in util.py, which is used to modify the model graph and load lora.

Function load_lora(lora_path, DEVICE_NAME) is used to load lora, get lora's shape and weights per layers and modify each layer's name.

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def load_lora(lora_path, DEVICE_NAME):
    state_dict = load_file(lora_path)
    if DEVICE_NAME =="CPU":
        for key, value in state_dict.items():
            if isinstance(value, torch.Tensor):
                    value_fp32 = value.type(torch.float32)
                    state_dict[key] = value_fp32

    layers_per_block = 2#TODO
    state_dict = _maybe_map_sgm_blocks_to_diffusers(state_dict, layers_per_block)
    state_dict, network_alphas = _convert_non_diffusers_lora_to_diffusers(state_dict)

    # now keys in format like: "unet.up_blocks.0.attentions.2.transformer_blocks.8.ff.net.2.lora.down.weight"'
    new_state_dict = {}
    for key , value in state_dict.items():
        if len(value.shape)==4:
            # new_value = torch.reshape(value, (value.shape[0],value.shape[1]))
            new_value = torch.squeeze(value)
        else:
            new_value = value
        new_state_dict[key.replace('.', '_').replace('_processor','')] = new_value
    # now keys in format like: "unet_up_blocks_0_attentions_2_transformer_blocks_8_ff_net_2_lora_down_weight"'

    LORA_PREFIX_UNET = "unet"
    LORA_PREFIX_TEXT_ENCODER = "text_encoder"
    LORA_PREFIX_TEXT_2_ENCODER = "text_encoder_2"

    lora_text_encoder_input_value_dict = {}
    lora_text_encoder_2_input_value_dict = {}
    lora_unet_input_value_dict = {}

    lora_alpha = collections.Counter(network_alphas.values()).most_common()[0][0]

    for key in new_state_dict.keys():
        if LORA_PREFIX_TEXT_ENCODER in key and "lora_down" in key and LORA_PREFIX_TEXT_2_ENCODER not in key:
            layer_infos = key.split(LORA_PREFIX_TEXT_ENCODER + "_")[-1]
            lora_text_encoder_input_value_dict[layer_infos] = new_state_dict[key]
            lora_text_encoder_input_value_dict[layer_infos.replace("lora_down", "lora_up")] = new_state_dict[key.replace("lora_down", "lora_up")]

        elif LORA_PREFIX_TEXT_2_ENCODER in key and "lora_down" in key:
            layer_infos = key.split(LORA_PREFIX_TEXT_2_ENCODER + "_")[-1]
            lora_text_encoder_2_input_value_dict[layer_infos] = new_state_dict[key]
            lora_text_encoder_2_input_value_dict[layer_infos.replace("lora_down", "lora_up")] = new_state_dict[key.replace("lora_down", "lora_up")]

        elif LORA_PREFIX_UNET in key and "lora_down" in key:
            layer_infos = key.split(LORA_PREFIX_UNET + "_")[-1]
            lora_unet_input_value_dict[layer_infos] = new_state_dict[key]
            lora_unet_input_value_dict[layer_infos.replace("lora_down", "lora_up")] = new_state_dict[key.replace("lora_down", "lora_up")]

    #now the keys in format without prefix

    return lora_text_encoder_input_value_dict, lora_text_encoder_2_input_value_dict, lora_unet_input_value_dict, lora_alpha

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Function add_param(model, lora_input_value_dict) is used to add input parameter per names of related layers, which will be connected to model with manager.register_pass(InsertLoRAUnet(input_param_dict)) and manager.register_pass(InsertLoRATE(input_param_dict)), in these two classes, we search the whole model graph to find the related layers by their names and connect them with lora.

def add_param(model, lora_input_value_dict):
        param_list = []
        for key, value in lora_input_value_dict.items():
            if '_lora_down' in key:
                key_down = key
                key_up = key_down.replace('_lora_down','_lora_up')
                name_alpha = key_down.replace('_lora_down','_lora_alpha')
                lora_alpha = ops.parameter(shape='',name=name_alpha)
                lora_alpha.output(0).set_names({name_alpha})
                # lora_down = ops.parameter(shape=[-1, lora_input_value_dict[key_down].shape[-1]], name=key_down)
                lora_down = ops.parameter(shape=lora_input_value_dict[key_down].shape, name=key_down)
                lora_down.output(0).set_names({key_down})
                # lora_up = ops.parameter(shape=[lora_input_value_dict[key_up].shape[0], -1], name=key_up)
                lora_up = ops.parameter(shape=lora_input_value_dict[key_up].shape, name=key_up)
                lora_up.output(0).set_names({key_up})
                param_list.append(lora_alpha)
                param_list.append(lora_down)
                param_list.append(lora_up)
        model.add_parameters(param_list)

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class InsertLoRAUnet(MatcherPass):
    def __init__(self, input_param_dict):
        MatcherPass.__init__(self)
        self.model_changed = False
        param = WrapType("opset10.Convert")

        def callback(matcher: Matcher) -> bool:
            root = matcher.get_match_root()
            root_output = matcher.get_match_value()
            for key in input_param_dict.keys():
                if root.get_friendly_name().replace('.','_').replace('self_unet_','') == key.replace('_lora_down','').replace('to_out','to_out_0'):

                    key_down = key
                    key_up = key_down.replace('_lora_down','_lora_up')
                    key_alpha = key_down.replace('_lora_down','_lora_alpha')

                    consumers = root_output.get_target_inputs()

                    lora_up_node = input_param_dict.pop(key_up)
                    lora_down_node = input_param_dict.pop(key_down)
                    lora_alpha_node = input_param_dict.pop(key_alpha)   

                    lora_weights = ops.matmul(data_a=lora_up_node, data_b=lora_down_node, transpose_a=False, transpose_b=False, name=key.replace('_down',''))
                    lora_weights_alpha = ops.multiply(lora_alpha_node, lora_weights)
                    if len(root.shape)!=len(lora_weights_alpha.shape):
                        # lora_weights_alpha_reshape = ops.reshape(lora_weights_alpha, root.shape, special_zero=False)
                        lora_weights_alpha_reshape = ops.unsqueeze(lora_weights_alpha, axes=[2, 3])
                        add_lora = ops.add(root,lora_weights_alpha_reshape,auto_broadcast='numpy')
                    else:
                        add_lora = ops.add(root,lora_weights_alpha,auto_broadcast='numpy')
                    for consumer in consumers:
                        consumer.replace_source_output(add_lora.output(0))

                    return True
            # Root node wasn't replaced or changed
            return False
        
        self.register_matcher(Matcher(param,"InsertLoRAUnet"), callback)

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class InsertLoRATE(MatcherPass):
    def __init__(self, input_param_dict):
        MatcherPass.__init__(self)
        self.model_changed = False
        param = WrapType("opset10.Convert")

        def callback(matcher: Matcher) -> bool:
            root = matcher.get_match_root()
            root_output = matcher.get_match_value()
            root_name = None
            if 'Constant_' in root.get_friendly_name() and root.shape == ov.Shape([768,768]):
                target_input = root.output(0).get_target_inputs()
                for v in target_input:
                    for input_of_MatMul in v.get_node().inputs():
                        if input_of_MatMul.get_shape()== ov.Shape([1,77,768]):
                            Add_Node = input_of_MatMul.get_source_output().get_node()
                            for Add_Node_output in Add_Node.output(0).get_target_inputs():
                                if 'k_proj' in Add_Node_output.get_node().get_friendly_name():
                                    for i in Add_Node_output.get_node().inputs():
                                        if i.get_shape() == ov.Shape([768,768]) and 'k_proj' in i.get_source_output().get_node().get_friendly_name():
                                            root_name = i.get_source_output().get_node().get_friendly_name().replace('k_proj', 'q_proj')

            root_friendly_name = root_name if root_name else root.get_friendly_name()
            
            for key in input_param_dict.keys():
                if root_friendly_name.replace('.','_').replace('self_','') == key.replace('_lora_down','_proj').replace('_to','').replace('_self',''):
                    # print(root_friendly_name)
                    key_down = key
                    key_up = key_down.replace('_lora_down','_lora_up')
                    key_alpha = key_down.replace('_lora_down','_lora_alpha')

                    consumers = root_output.get_target_inputs()

                    lora_up_node = input_param_dict.pop(key_up)
                    lora_down_node = input_param_dict.pop(key_down)
                    lora_alpha_node = input_param_dict.pop(key_alpha)   

                    lora_weights = ops.matmul(data_a=lora_up_node, data_b=lora_down_node, transpose_a=False, transpose_b=False, name=key.replace('_down',''))
                    lora_weights_alpha = ops.multiply(lora_alpha_node, lora_weights)
                    add_lora = ops.add(root,lora_weights_alpha,auto_broadcast='numpy')
                    for consumer in consumers:
                        consumer.replace_source_output(add_lora.output(0))

                    return True
                
            if len(input_param_dict) == 0:
                print("All loras are added")
            # Root node wasn't replaced or changed
            return False
        
        self.register_matcher(Matcher(param,"InsertLoRATE"), callback)

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4. GenAI

In addition to this, the latest OpenVINO GenAI provides the Cpp API for LoRA. You can find it here.

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Authors: Xiake Sun, Su Yang, Tianmeng Chen, Tong Qiu

openvino.genai/samples/cpp/rag_sample at openvino_genai_serving · sammysun0711/openvino.genai (github.com)

OpenVINO GenAI Server (OGS) Update:

-Update LLM: stream generation, reset handle, multi-round chat, model cache config

-Support VLM

-Support Reranker for RAG sample

-Support BLIP image embedding for photo search with DB

-Support C++ GUI with imgui for photo search

Now we scale the text embedding to image embedding for RAG sample and support multi-Vector Retriever for RAG.

1. Multi-Vector Retriever for RAG on text: QA over Document
2. Multi-Vector Retriever for RAG on image: Photo search with DB retrieval

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Here is a photo search sample with image embedding.

Usage 2: Photo Search with DB retrieval

Steps:

1.use python client to create image vector DB (PostgreSQL)

2.use GUI to search image

Here is a sample image to demonstrate GUI usage on client platform. we search the bus photo with top 10 similar images from the 100 images which are embedded into Vector DB.

Usage 3: Chat with images via MiniCPM-V

Once we have created a multimodal vector DB through image embedding, we can further communicate with the image through VLM.

We integrate the C++ GenAI sample visual_language_chat with openbmb/MiniCPM-V-2_6.

Here is the demo image on client platform.

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Authors: Tianmeng Chen, Xiake Sun

Introduction

Stable Diffusion is a generative artificial intelligence model that produces unique images from text and image prompts. ControlNet is a neural network that controls image generation in Stable Diffusion by adding extra conditions. The specific structure of Stable Diffusion + ControlNet is shown below:

In many cases, ControlNet is used in conjunction with other models or frameworks, such as OpenPose, Canny, Line Art, Depth, etc. An example of Stable Diffusion + ControlNet + OpenPose:

OpenPose identifies the key points of the human body from the left image to get the pose image, and then inputs the Pose image to ControlNet and Stable Diffusion to get the right image. In this way, ControlNet can control the generation of Stable Diffusion.

In this blog, we focus on enabling the stable diffusion pipeline with ControlNet in Optimum-intel. Some details can be found in this open PR.

How to enable StableDiffusionControlNet pipeline in Optimum-Intel

The important code is in optimum/intel/openvino/modelling_diffusion.py and optimum/exporters/openvino/model_configs.py. There is the diffusion pipeline related code in file modelling_diffusion.py, you can find several Class: OVStableDiffusionPipelineBase, OVStableDiffusionPipeline, OVStableDiffusionXLPipelineBase, OVStableDiffusionXLPipeline, and so on. What we need to do is mimic these base classes to add the OVStableDiffusionControlNetPipelineBase, StableDiffusionContrlNetPipelineMixin, and OVStableDiffusionControlNetPipeline. A few of the important parts are as follows:

_from_pretrained function in class OVStableDiffusionControlNetPipelineBase: initial whole pipeline from local or download.

_from_transformers function in class OVStableDiffusionControlNetPipelineBase: convert torch model to OpenVINO IR model.

_reshape_unet_controlnet and _reshape_controlnet in class OVStableDiffusionControlNetPipelineBase: reshape dynamic OpenVINO IR model to static in order to decrease cost.

__call__ function in class StableDiffusionContrlNetPipelineMixin: do the inference in the pipeline.

In model_configs.py, we define UNetControlNetOpenVINOConfig by inheriting UNetOnnxConfig, which includes UNetControlNet inputs and outputs.

By now we have completed the rough code, after which some very detailed code additions are needed, so I won't go into that here.

How to use StableDiffusionControlNet pipeline via Optimum-Intel

The next step is how to use the code, examples of which can be found in this repository.

Installation and update of environments and dependencies from source. Make sure your python version is greater that 3.10 and your optimum-intel and optimum version is up to date accounding to the requirements.txt.

# %python -m venv stable-diffusion-controlnet
# %source stable-diffusion-controlnet/bin/activate
%pip install -r requirements.txt

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At first, we should convert pytorch model to openvino IR with dynamic shape. Now import related packages.

from optimum.intel import OVStableDiffusionControlNetPipeline
import os
from diffusers import UniPCMultistepScheduler

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Set pytroch models of stable diffusion 1.5 and controlnet path if you have them in local, else you can run pipeline from download.

SD15_PYTORCH_MODEL_DIR="stable-diffusion-v1-5"
CONTROLNET_PYTORCH_MODEL_DIR="control_v11p_sd15_openpose"


if os.path.exists(SD15_PYTORCH_MODEL_DIR) and os.path.exists(CONTROLNET_PYTORCH_MODEL_DIR):
    scheduler = UniPCMultistepScheduler.from_config("scheduler_config.json")
    ov_pipe = OVStableDiffusionControlNetPipeline.from_pretrained(SD15_PYTORCH_MODEL_DIR, controlnet_model_id=CONTROLNET_PYTORCH_MODEL_DIR, compile=False, export=True, scheduler=scheduler,device="GPU.1")
    ov_pipe.save_pretrained(save_directory="./ov_models_dynamic")
    print("Dynamic model is saved in ./ov_models_dynamic")  

else:
    scheduler = UniPCMultistepScheduler.from_config("scheduler_config.json")
    ov_pipe = OVStableDiffusionControlNetPipeline.from_pretrained("runwayml/stable-diffusion-v1-5", controlnet_model_id="lllyasviel/control_v11p_sd15_openpose", compile=False, export=True, scheduler=scheduler, device="GPU.1")
    ov_pipe.save_pretrained(save_directory="./ov_models_dynamic")
    print("Dynamic model is saved in ./ov_models_dynamic")

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Now you will have openvino IR models file under **ov_models_dynamic ** folder.

from optimum.intel import OVStableDiffusionControlNetPipeline
from controlnet_aux import OpenposeDetector
from pathlib import Path
import numpy as np
import os
from PIL import Image
from diffusers import UniPCMultistepScheduler
import requests
import torch

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We recommand to use static shape model to decrease GPU memory cost. Set your STATIC_SHAPE and DEVICE_NAME.

NEED_STATIC = True
STATIC_SHAPE = [1024,1024]
DEVICE_NAME = "GPU.1"

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Load openvino model files, if is static, reshape dynamic models to fixed shape.

if NEED_STATIC:
    print("Using static models")
    scheduler = UniPCMultistepScheduler.from_config("scheduler_config.json")
    ov_config ={"CACHE_DIR": "", 'INFERENCE_PRECISION_HINT': 'f16'}
    if not os.path.exists("ov_models_static"):
        if os.path.exists("ov_models_dynamic"):
            print("load dynamic models from local ov files and reshape to static")
            ov_pipe = OVStableDiffusionControlNetPipeline.from_pretrained(Path("ov_models_dynamic"), scheduler=scheduler, device=DEVICE_NAME, compile=True, ov_config=ov_config, height=STATIC_SHAPE[0], width=STATIC_SHAPE[1])
            ov_pipe.reshape(batch_size=1 ,height=STATIC_SHAPE[0], width=STATIC_SHAPE[1], num_images_per_prompt=1)
            ov_pipe.save_pretrained(save_directory="./ov_models_static")
            print("Static model is saved in ./ov_models_static")  
        else:
            raise ValueError("No ov_models_dynamic exists, please trt ov_model_export.py first")
    else:
        print("load static models from local ov files")
        ov_pipe = OVStableDiffusionControlNetPipeline.from_pretrained(Path("ov_models_static"), scheduler=scheduler, device=DEVICE_NAME, compile=True, ov_config=ov_config, height=STATIC_SHAPE[0], width=STATIC_SHAPE[1])
else:
    scheduler = UniPCMultistepScheduler.from_config("scheduler_config.json")
    ov_config ={"CACHE_DIR": "", 'INFERENCE_PRECISION_HINT': 'f16'}
    print("load dynamic models from local ov files")
    ov_pipe = OVStableDiffusionControlNetPipeline.from_pretrained(Path("ov_models_dynamic"), scheduler=scheduler, device=DEVICE_NAME, compile=True, ov_config=ov_config)
     

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Set seed for Numpy and torch to make result reproducible.

seed = 42
torch.manual_seed(seed)           
torch.cuda.manual_seed(seed)       
torch.cuda.manual_seed_all(seed)
np.random.seed(seed)

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Load image for ControlNet, or you can use your own image, or generate image with OpenPose OpenVINO model, notice that OpenPose model is not supported by OVStableDiffusionControlNetPipeline yet, so you need to convert it to openvino model first manually. Here we use directly the result from OpenPose:

pose = Image.open(Path("pose_1024.png"))

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Set prompt, negative_prompt, image inputs.

prompt = "Dancing Darth Vader, best quality, extremely detailed"
negative_prompt = "monochrome, lowres, bad anatomy, worst quality, low quality"

result = ov_pipe(prompt=prompt, image=pose, num_inference_steps=20, negative_prompt=negative_prompt, height=STATIC_SHAPE[0], width=STATIC_SHAPE[1])

result[0].save("result_1024.png")

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