Load LoRA XXX.safetensors to diffusers (StableDiffusionPipeline/StableDiffusionControlNetPipeline)_.safetensors转diffuser

def load_lora_weights(pipeline, checkpoint_path, multiplier, device, dtype):
    LORA_PREFIX_UNET = "lora_unet"
    LORA_PREFIX_TEXT_ENCODER = "lora_te"
    # load LoRA weight from .safetensors
    state_dict = load_file(checkpoint_path, device=device)
 
    updates = defaultdict(dict)
    for key, value in state_dict.items():
        # it is suggested to print out the key, it usually will be something like below
        # "lora_te_text_model_encoder_layers_0_self_attn_k_proj.lora_down.weight"
 
        layer, elem = key.split('.', 1)
        updates[layer][elem] = value
 
    # directly update weight in diffusers model
    for layer, elems in updates.items():
 
        if "text" in layer:
            layer_infos = layer.split(LORA_PREFIX_TEXT_ENCODER + "_")[-1].split("_")
            curr_layer = pipeline.text_encoder
        else:
            layer_infos = layer.split(LORA_PREFIX_UNET + "_")[-1].split("_")
            curr_layer = pipeline.unet
 
        # find the target layer
        temp_name = layer_infos.pop(0)
        while len(layer_infos) > -1:
            try:
                curr_layer = curr_layer.__getattr__(temp_name)
                if len(layer_infos) > 0:
                    temp_name = layer_infos.pop(0)
                elif len(layer_infos) == 0:
                    break
            except Exception:
                if len(temp_name) > 0:
                    temp_name += "_" + layer_infos.pop(0)
                else:
                    temp_name = layer_infos.pop(0)
 
        # get elements for this layer
        weight_up = elems['lora_up.weight'].to(dtype)
        weight_down = elems['lora_down.weight'].to(dtype)
        alpha = elems['alpha']
        if alpha:
            alpha = alpha.item() / weight_up.shape[1]
        else:
            alpha = 1.0
 
        curr_layer.weight.data = curr_layer.weight.data.to(device) 
        # update weight
        if len(weight_up.shape) == 4:
            curr_layer.weight.data += multiplier * alpha * torch.mm(weight_up.squeeze(3).squeeze(2), weight_down.squeeze(3).squeeze(2)).unsqueeze(2).unsqueeze(3)
        else:
            curr_layer.weight.data += multiplier * alpha * torch.mm(weight_up, weight_down)
 
    return pipeline

Example usage:

pipe = load_lora_weights(pipe, lora_path, 1.0, 'cuda', torch.float16)