feat: add LoRA support

README.md

@@ -18,6 +18,8 @@ Inference of [Stable Diffusion](https://github.com/CompVis/stable-diffusion) in
 - Original `txt2img` and `img2img` mode
 - Negative prompt
 - [stable-diffusion-webui](https://github.com/AUTOMATIC1111/stable-diffusion-webui) style tokenizer (not all the features, only token weighting for now)
+- LoRA support, same as [stable-diffusion-webui](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Features#lora)
+- Latent Consistency Models support(LCM/LCM-LoRA)
 - Sampling method
     - `Euler A`
     - `Euler`
@@ -42,7 +44,6 @@ Inference of [Stable Diffusion](https://github.com/CompVis/stable-diffusion) in
 - [ ] Make inference faster
     - The current implementation of ggml_conv_2d is slow and has high memory usage
 - [ ] Continuing to reduce memory usage (quantizing the weights of ggml_conv_2d)
-- [ ] LoRA support
 - [ ] k-quants support
 
 ## Usage
@@ -125,6 +126,7 @@ arguments:
   -t, --threads N                    number of threads to use during computation (default: -1).
                                      If threads <= 0, then threads will be set to the number of CPU physical cores
   -m, --model [MODEL]                path to model
+  --lora-model-dir [DIR]             lora model directory
   -i, --init-img [IMAGE]             path to the input image, required by img2img
   -o, --output OUTPUT                path to write result image to (default: .\output.png)
   -p, --prompt [PROMPT]              the prompt to render
@@ -134,11 +136,12 @@ arguments:
                                      1.0 corresponds to full destruction of information in init image
   -H, --height H                     image height, in pixel space (default: 512)
   -W, --width W                      image width, in pixel space (default: 512)
-  --sampling-method {euler, euler_a, heun, dpm++2m, dpm++2mv2, lcm}
+  --sampling-method {euler, euler_a, heun, dpm2, dpm++2s_a, dpm++2m, dpm++2mv2, lcm}
                                      sampling method (default: "euler_a")
   --steps  STEPS                     number of sample steps (default: 20)
   --rng {std_default, cuda}          RNG (default: cuda)
   -s SEED, --seed SEED               RNG seed (default: 42, use random seed for < 0)
+  --schedule {discrete, karras}      Denoiser sigma schedule (default: discrete)
   -v, --verbose                      print extra info
 ```
 
@@ -167,6 +170,45 @@ Using formats of different precisions will yield results of varying quality.
   <img src="./assets/img2img_output.png" width="256x">
 </p>
 
+#### with LoRA
+
+- convert lora weights to ggml model format
+
+    ```shell
+    cd models
+    python convert.py [path to weights] --lora
+    # For example, python convert.py marblesh.safetensors
+    ```
+
+- You can specify the directory where the lora weights are stored via `--lora-model-dir`. If not specified, the default is the current working directory.
+
+- LoRA is specified via prompt, just like [stable-diffusion-webui](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Features#lora).
+
+Here's a simple example:
+
+```
+./bin/sd -m ../models/v1-5-pruned-emaonly-ggml-model-f16.bin -p "a lovely cat<lora:marblesh:1>" --lora-model-dir ../models
+```
+
+`../models/marblesh-ggml-lora.bin` will be applied to the model
+
+#### LCM/LCM-LoRA
+
+- Download LCM-LoRA form https://huggingface.co/latent-consistency/lcm-lora-sdv1-5
+- Specify LCM-LoRA by adding `<lora:lcm-lora-sdv1-5:1>` to prompt
+- It's advisable to set `--cfg-scale` to `1.0` instead of the default `7.0`. For `--steps`, a range of `2-8` steps is recommended. For `--sampling-method`, `lcm`/`euler_a` is recommended.
+
+Here's a simple example:
+
+```
+./bin/sd -m ../models/v1-5-pruned-emaonly-ggml-model-f16.bin -p "a lovely cat<lora:lcm-lora-sdv1-5:1>" --steps 4 --lora-model-dir ../models -v --cfg-scale 1
+```
+
+| without LCM-LoRA (--cfg-scale 7)  | with LCM-LoRA (--cfg-scale 1)  |
+| ----  |----    |
+| ![](./assets/without_lcm.png) |![](./assets/with_lcm.png)  |
+
+
 ### Docker
 
 #### Building using Docker

examples/main.cpp

@@ -95,6 +95,7 @@ struct Option {
     int n_threads = -1;
     std::string mode = TXT2IMG;
     std::string model_path;
+    std::string lora_model_dir;
     std::string output_path = "output.png";
     std::string init_img;
     std::string prompt;
@@ -115,6 +116,7 @@ struct Option {
         printf("    n_threads:       %d\n", n_threads);
         printf("    mode:            %s\n", mode.c_str());
         printf("    model_path:      %s\n", model_path.c_str());
+        printf("    lora_model_dir:  %s\n", lora_model_dir.c_str());
         printf("    output_path:     %s\n", output_path.c_str());
         printf("    init_img:        %s\n", init_img.c_str());
         printf("    prompt:          %s\n", prompt.c_str());
@@ -127,7 +129,7 @@ struct Option {
         printf("    sample_steps:    %d\n", sample_steps);
         printf("    strength:        %.2f\n", strength);
         printf("    rng:             %s\n", rng_type_to_str[rng_type]);
-        printf("    seed:            %ld\n", seed);
+        printf("    seed:            %lld\n", seed);
     }
 };
 
@@ -140,6 +142,7 @@ void print_usage(int argc, const char* argv[]) {
     printf("  -t, --threads N                    number of threads to use during computation (default: -1).\n");
     printf("                                     If threads <= 0, then threads will be set to the number of CPU physical cores\n");
     printf("  -m, --model [MODEL]                path to model\n");
+    printf("  --lora-model-dir [DIR]             lora model directory\n");
     printf("  -i, --init-img [IMAGE]             path to the input image, required by img2img\n");
     printf("  -o, --output OUTPUT                path to write result image to (default: .\\output.png)\n");
     printf("  -p, --prompt [PROMPT]              the prompt to render\n");
@@ -183,6 +186,12 @@ void parse_args(int argc, const char* argv[], Option* opt) {
                 break;
             }
             opt->model_path = argv[i];
+        } else if (arg == "--lora-model-dir") {
+            if (++i >= argc) {
+                invalid_arg = true;
+                break;
+            }
+            opt->lora_model_dir = argv[i];
         } else if (arg == "-i" || arg == "--init-img") {
             if (++i >= argc) {
                 invalid_arg = true;
@@ -419,7 +428,7 @@ int main(int argc, const char* argv[]) {
         init_img.assign(img_data, img_data + (opt.w * opt.h * c));
     }
 
-    StableDiffusion sd(opt.n_threads, vae_decode_only, true, opt.rng_type);
+    StableDiffusion sd(opt.n_threads, vae_decode_only, true, opt.lora_model_dir, opt.rng_type);
     if (!sd.load_from_file(opt.model_path, opt.schedule)) {
         return 1;
     }

models/convert.py

@@ -4,6 +4,7 @@ import os
 
 import numpy as np
 import torch
+import re
 import safetensors.torch
 
 this_file_dir = os.path.dirname(__file__)
@@ -270,21 +271,107 @@ def preprocess(state_dict):
         new_state_dict[name] = w
     return new_state_dict
 
-def convert(model_path, out_type = None, out_file=None):
+re_digits = re.compile(r"\d+")
+re_x_proj = re.compile(r"(.*)_([qkv]_proj)$")
+re_compiled = {}
+
+suffix_conversion = {
+    "attentions": {},
+    "resnets": {
+        "conv1": "in_layers_2",
+        "conv2": "out_layers_3",
+        "norm1": "in_layers_0",
+        "norm2": "out_layers_0",
+        "time_emb_proj": "emb_layers_1",
+        "conv_shortcut": "skip_connection",
+    }
+}
+
+
+def convert_diffusers_name_to_compvis(key):
+    def match(match_list, regex_text):
+        regex = re_compiled.get(regex_text)
+        if regex is None:
+            regex = re.compile(regex_text)
+            re_compiled[regex_text] = regex
+
+        r = re.match(regex, key)
+        if not r:
+            return False
+
+        match_list.clear()
+        match_list.extend([int(x) if re.match(re_digits, x) else x for x in r.groups()])
+        return True
+
+    m = []
+
+    if match(m, r"lora_unet_conv_in(.*)"):
+        return f'model_diffusion_model_input_blocks_0_0{m[0]}'
+
+    if match(m, r"lora_unet_conv_out(.*)"):
+        return f'model_diffusion_model_out_2{m[0]}'
+
+    if match(m, r"lora_unet_time_embedding_linear_(\d+)(.*)"):
+        return f"model_diffusion_model_time_embed_{m[0] * 2 - 2}{m[1]}"
+
+    if match(m, r"lora_unet_down_blocks_(\d+)_(attentions|resnets)_(\d+)_(.+)"):
+        suffix = suffix_conversion.get(m[1], {}).get(m[3], m[3])
+        return f"model_diffusion_model_input_blocks_{1 + m[0] * 3 + m[2]}_{1 if m[1] == 'attentions' else 0}_{suffix}"
+
+    if match(m, r"lora_unet_mid_block_(attentions|resnets)_(\d+)_(.+)"):
+        suffix = suffix_conversion.get(m[0], {}).get(m[2], m[2])
+        return f"model_diffusion_model_middle_block_{1 if m[0] == 'attentions' else m[1] * 2}_{suffix}"
+
+    if match(m, r"lora_unet_up_blocks_(\d+)_(attentions|resnets)_(\d+)_(.+)"):
+        suffix = suffix_conversion.get(m[1], {}).get(m[3], m[3])
+        return f"model_diffusion_model_output_blocks_{m[0] * 3 + m[2]}_{1 if m[1] == 'attentions' else 0}_{suffix}"
+
+    if match(m, r"lora_unet_down_blocks_(\d+)_downsamplers_0_conv"):
+        return f"model_diffusion_model_input_blocks_{3 + m[0] * 3}_0_op"
+
+    if match(m, r"lora_unet_up_blocks_(\d+)_upsamplers_0_conv"):
+        return f"model_diffusion_model_output_blocks_{2 + m[0] * 3}_{2 if m[0]>0 else 1}_conv"
+
+    if match(m, r"lora_te_text_model_encoder_layers_(\d+)_(.+)"):
+        return f"cond_stage_model_transformer_text_model_encoder_layers_{m[0]}_{m[1]}"
+
+    return None
+
+def preprocess_lora(state_dict):
+    new_state_dict = {}
+    for name, w in state_dict.items():
+        if not isinstance(w, torch.Tensor):
+            continue
+        name_without_network_parts, network_part = name.split(".", 1)
+        new_name_without_network_parts = convert_diffusers_name_to_compvis(name_without_network_parts)
+        if new_name_without_network_parts == None:
+            raise Exception(f"unknown lora tensor: {name}")
+        new_name = new_name_without_network_parts + "." + network_part
+        print(f"preprocess {name} => {new_name}")
+        new_state_dict[new_name] = w
+    return new_state_dict
+
+def convert(model_path, out_type = None, out_file=None, lora=False):
     # load model
+    if not lora:
         with open(os.path.join(vocab_dir, "vocab.json"), encoding="utf-8") as f:
             clip_vocab = json.load(f)
 
     state_dict = load_model_from_file(model_path)
-    model_type = SD1
-    if "cond_stage_model.model.token_embedding.weight" in state_dict.keys():
+    model_type = SD1 # lora only for SD1 now
+    if not lora and "cond_stage_model.model.token_embedding.weight" in state_dict.keys():
         model_type = SD2
         print("Stable diffuison 2.x")
     else:
         print("Stable diffuison 1.x")
+    if lora:
+        state_dict = preprocess_lora(state_dict)
+    else:
         state_dict = preprocess(state_dict)
 
     # output option
+    if lora:
+        out_type = "f16" # only f16 for now
     if out_type == None:
         weight = state_dict["model.diffusion_model.input_blocks.0.0.weight"].numpy()
         if weight.dtype == np.float32:
@@ -296,6 +383,9 @@ def convert(model_path, out_type = None, out_file=None):
         else:
             raise Exception("unsupported weight type %s" % weight.dtype)
     if out_file == None:
+        if lora:
+            out_file = os.path.splitext(os.path.basename(model_path))[0] + f"-ggml-lora.bin"
+        else:
             out_file = os.path.splitext(os.path.basename(model_path))[0] + f"-ggml-model-{out_type}.bin"
         out_file = os.path.join(os.getcwd(), out_file)
     print(f"Saving GGML compatible file to {out_file}")
@@ -309,6 +399,7 @@ def convert(model_path, out_type = None, out_file=None):
         file.write(struct.pack("i", ftype))
 
         # vocab
+        if not lora:
             byte_encoder = bytes_to_unicode()
             byte_decoder = {v: k for k, v in byte_encoder.items()}
             file.write(struct.pack("i", len(clip_vocab)))
@@ -337,7 +428,7 @@ def convert(model_path, out_type = None, out_file=None):
             old_type = data.dtype
 
             ttype = "f32"
-            if n_dims == 4:
+            if n_dims == 4 and not lora:
                 data = data.astype(np.float16)
                 ttype = "f16"
             elif n_dims == 2 and name[-7:] == ".weight":
@@ -380,6 +471,7 @@ if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Convert Stable Diffuison model to GGML compatible file format")
     parser.add_argument("--out_type", choices=["f32", "f16", "q4_0", "q4_1", "q5_0", "q5_1", "q8_0"], help="output format (default: based on input)")
     parser.add_argument("--out_file", help="path to write to; default: based on input and current working directory")
+    parser.add_argument("--lora", action='store_true', default = False, help="convert lora weight; default: false")
     parser.add_argument("model_path", help="model file path (*.pth, *.pt, *.ckpt, *.safetensors)")
     args = parser.parse_args()
-    convert(args.model_path, args.out_type, args.out_file)
+    convert(args.model_path, args.out_type, args.out_file, args.lora)

stable-diffusion.cpp

@@ -268,6 +268,45 @@ struct ggml_tensor* ggml_group_norm_32(struct ggml_context* ctx,
     return ggml_group_norm(ctx, a, 32);
 }
 
+std::pair<std::unordered_map<std::string, float>, std::string> extract_and_remove_lora(std::string text) {
+    std::regex re("<lora:([^:]+):([^>]+)>");
+    std::smatch matches;
+    std::unordered_map<std::string, float> filename2multiplier;
+
+    while (std::regex_search(text, matches, re)) {
+        std::string filename = matches[1].str();
+        float multiplier = std::stof(matches[2].str());
+        if (multiplier < 0.f) {
+            continue;
+        }
+        if (filename2multiplier.find(filename) == filename2multiplier.end()) {
+            filename2multiplier[filename] = multiplier;
+        } else {
+            filename2multiplier[filename] += multiplier;
+        }
+
+        text = std::regex_replace(text, re, "");
+    }
+
+    return std::make_pair(filename2multiplier, text);
+}
+
+bool ends_with(const std::string& str, const std::string& ending) {
+    if (str.length() >= ending.length()) {
+        return (str.compare(str.length() - ending.length(), ending.length(), ending) == 0);
+    } else {
+        return false;
+    }
+}
+
+void replace_all_chars(std::string& str, char target, char replacement) {
+    for (size_t i = 0; i < str.length(); ++i) {
+        if (str[i] == target) {
+            str[i] = replacement;
+        }
+    }
+}
+
 /*================================================== CLIPTokenizer ===================================================*/
 
 const std::string UNK_TOKEN = "<|endoftext|>";
@@ -2794,6 +2833,16 @@ class StableDiffusionGGML {
     UNetModel diffusion_model;
     AutoEncoderKL first_stage_model;
 
+    std::map<std::string, struct ggml_tensor*> tensors;
+
+    std::string lora_model_dir;
+    // lora_name => lora_tensor_name => tensor
+    std::map<std::string, std::map<std::string, struct ggml_tensor*>> lora_tensors;
+    // lora_name => lora_params_ctx
+    std::map<std::string, ggml_context*> lora_params_ctxs;
+    // lora_name => multiplier
+    std::unordered_map<std::string, float> curr_lora_state;
+
     std::shared_ptr<Denoiser> denoiser = std::make_shared<CompVisDenoiser>();
 
     StableDiffusionGGML() = default;
@@ -2801,16 +2850,23 @@ class StableDiffusionGGML {
     StableDiffusionGGML(int n_threads,
                         bool vae_decode_only,
                         bool free_params_immediately,
+                        std::string lora_model_dir,
                         RNGType rng_type)
         : n_threads(n_threads),
           vae_decode_only(vae_decode_only),
-          free_params_immediately(free_params_immediately) {
+          free_params_immediately(free_params_immediately),
+          lora_model_dir(lora_model_dir) {
         first_stage_model.decode_only = vae_decode_only;
         if (rng_type == STD_DEFAULT_RNG) {
             rng = std::make_shared<STDDefaultRNG>();
         } else if (rng_type == CUDA_RNG) {
             rng = std::make_shared<PhiloxRNG>();
         }
+        if (lora_model_dir.size() > 0) {
+            if (lora_model_dir[lora_model_dir.size() - 1] != '/' && lora_model_dir[lora_model_dir.size() - 1] != '\\') {
+                this->lora_model_dir = lora_model_dir + "/";
+            }
+        }
     }
 
     ~StableDiffusionGGML() {
@@ -2826,6 +2882,13 @@ class StableDiffusionGGML {
             ggml_free(vae_params_ctx);
             vae_params_ctx = NULL;
         }
+        for (auto& kv : lora_params_ctxs) {
+            ggml_free(kv.second);
+        }
+        lora_params_ctxs.clear();
+
+        tensors.clear();
+        lora_tensors.clear();
     }
 
     bool load_from_file(const std::string& file_path, Schedule schedule) {
@@ -2963,8 +3026,6 @@ class StableDiffusionGGML {
             }
         }
 
-        std::map<std::string, struct ggml_tensor*> tensors;
-
         LOG_DEBUG("preparing memory for the weights");
         // prepare memory for the weights
         {
@@ -3255,6 +3316,306 @@ class StableDiffusionGGML {
         return result < -1;
     }
 
+    bool load_lora_from_file(const std::string& lora_name) {
+        if (lora_tensors.find(lora_name) != lora_tensors.end()) {
+            return true;
+        }
+        std::string file_path = lora_model_dir + lora_name + "-ggml-lora.bin";
+        LOG_INFO("loading lora '%s' from '%s'", lora_name.c_str(), file_path.c_str());
+
+        std::ifstream file(file_path, std::ios::binary);
+        if (!file.is_open()) {
+            LOG_ERROR("failed to open '%s'", file_path.c_str());
+            return false;
+        }
+
+        // get file size
+        file.seekg(0, file.end);
+        int file_size = (int)file.tellg();
+        file.seekg(0, file.beg);
+
+        LOG_DEBUG("'%s': %.2fMB", file_path.c_str(), file_size * 1.f / 1024 / 1024);
+
+        LOG_DEBUG("verifying magic");
+        // verify magic
+        {
+            uint32_t magic;
+            file.read(reinterpret_cast<char*>(&magic), sizeof(magic));
+            if (magic != GGML_FILE_MAGIC) {
+                LOG_ERROR("invalid model file '%s' (bad magic)", file_path.c_str());
+                return false;
+            }
+        }
+
+        LOG_DEBUG("loading hparams");
+        // load hparams
+        file.read(reinterpret_cast<char*>(&ftype), sizeof(ftype));
+
+        int model_type = (ftype >> 16) & 0xFFFF;
+        if (model_type >= MODEL_TYPE_COUNT) {
+            LOG_ERROR("invalid model file '%s' (bad model type value %d)", file_path.c_str(), ftype);
+            return false;
+        }
+        LOG_INFO("lora model type: %s", model_type_to_str[model_type]);
+
+        ggml_type wtype = ggml_ftype_to_ggml_type((ggml_ftype)(ftype & 0xFFFF));
+        LOG_INFO("ftype: %s", ggml_type_name(wtype));
+        if (wtype == GGML_TYPE_COUNT) {
+            LOG_ERROR("invalid model file '%s' (bad ftype value %d)", file_path.c_str(), ftype);
+            return false;
+        }
+
+        // create the ggml context for network params
+        struct ggml_init_params params;
+        size_t ctx_size = 10 * 1024 * 1024;  // 10 MB, for padding
+        ctx_size += file_size;
+        params.mem_size = ctx_size;
+        params.mem_buffer = NULL;
+        params.no_alloc = false;
+        params.dynamic = false;
+        LOG_DEBUG("lora '%s' params ctx size = % 6.2f MB", lora_name.c_str(), ctx_size / (1024.0 * 1024.0));
+        ggml_context* lora_params_ctx = ggml_init(params);
+        if (!lora_params_ctx) {
+            LOG_ERROR("ggml_init() failed");
+            return false;
+        }
+        lora_params_ctxs[lora_name] = lora_params_ctx;
+
+        std::map<std::string, struct ggml_tensor*> lora_tensor_map;
+        int64_t t0 = ggml_time_ms();
+        // load weights
+        {
+            int n_tensors = 0;
+            size_t total_size = 0;
+
+            while (true) {
+                int32_t n_dims;
+                int32_t length;
+                int32_t ttype;
+
+                file.read(reinterpret_cast<char*>(&n_dims), sizeof(n_dims));
+                file.read(reinterpret_cast<char*>(&length), sizeof(length));
+                file.read(reinterpret_cast<char*>(&ttype), sizeof(ttype));
+
+                if (file.eof()) {
+                    break;
+                }
+
+                int32_t nelements = 1;
+                int32_t ne[4] = {1, 1, 1, 1};
+                for (int i = 0; i < n_dims; ++i) {
+                    file.read(reinterpret_cast<char*>(&ne[i]), sizeof(ne[i]));
+                    nelements *= ne[i];
+                }
+
+                const size_t num_bytes = nelements / ggml_blck_size(ggml_type(ttype)) * ggml_type_size(ggml_type(ttype));
+
+                std::string name_buf(length, 0);
+                file.read(&name_buf[0], length);
+                std::string name = std::string(name_buf.data());
+
+                // LOG_DEBUG("load lora tensor %s", name.c_str());
+
+                int64_t ne64[4] = {ne[0], ne[1], ne[2], ne[3]};
+                struct ggml_tensor* tensor = ggml_new_tensor(lora_params_ctx, (ggml_type)ttype, n_dims, ne64);
+                file.read(reinterpret_cast<char*>(tensor->data), num_bytes);
+
+                lora_tensor_map[name] = tensor;
+
+                total_size += ggml_nbytes(tensor);
+            }
+        }
+        lora_tensors[lora_name] = lora_tensor_map;
+        int64_t t1 = ggml_time_ms();
+        LOG_INFO("lora '%s' params size = %.2fMB",
+                 lora_name.c_str(),
+                 ggml_used_mem(lora_params_ctx) / 1024.0 / 1024.0);
+        LOG_INFO("loading lora from '%s' completed, taking %.2fs", file_path.c_str(), (t1 - t0) * 1.0f / 1000);
+        file.close();
+        return true;
+    }
+
+    void remove_lora_params(const std::string& lora_name) {
+        if (lora_params_ctxs.find(lora_name) == lora_params_ctxs.end()) {
+            return;
+        }
+        ggml_free(lora_params_ctxs[lora_name]);
+        lora_params_ctxs.erase(lora_name);
+        lora_tensors.erase(lora_name);
+    }
+
+    void apply_lora(const std::string& lora_name, float multiplier) {
+        int64_t t0 = ggml_time_ms();
+        if (!load_lora_from_file(lora_name)) {
+            std::string file_path = lora_model_dir + lora_name + "-ggml-lora.bin";
+            LOG_WARN("apply lora '%s' failed", lora_name.c_str());
+            return;
+        }
+
+        size_t ctx_size = 500 * 1024 * 1024;  // 500MB
+        void* mem_buffer = malloc(ctx_size);
+        if (!mem_buffer) {
+            if (free_params_immediately) {
+                remove_lora_params(lora_name);
+            }
+            LOG_ERROR("malloc() failed");
+            return;
+        }
+
+        std::map<std::string, struct ggml_tensor*>& lora_tensor_map = lora_tensors[lora_name];
+        std::set<std::string> applied_lora_tensors;
+        for (auto& kv : tensors) {
+            const std::string name = kv.first;
+            ggml_tensor* weight = kv.second;
+            std::string ending = ".weight";
+            if (!ends_with(name, ending)) {
+                continue;
+            }
+
+            // find corresponding lora tensors
+            std::string network_name = name.substr(0, name.size() - ending.size());  // remove .weight
+            replace_all_chars(network_name, '.', '_');
+            std::string lora_up_name = network_name + ".lora_up.weight";
+            std::string lora_down_name = network_name + ".lora_down.weight";
+            std::string alpha_name = network_name + ".alpha";
+            std::string scale_name = network_name + ".scale";
+
+            ggml_tensor* lora_up = NULL;
+            ggml_tensor* lora_down = NULL;
+
+            float scale = 1.0f;
+
+            if (lora_tensor_map.find(lora_up_name) != lora_tensor_map.end()) {
+                lora_up = lora_tensor_map[lora_up_name];
+            }
+
+            if (lora_tensor_map.find(lora_down_name) != lora_tensor_map.end()) {
+                lora_down = lora_tensor_map[lora_down_name];
+            }
+
+            if (lora_up == NULL || lora_down == NULL) {
+                continue;
+            }
+
+            // LOG_DEBUG("apply lora tensor %s [%ld %ld %ld %ld]", network_name.c_str(), weight->ne[0], weight->ne[1], weight->ne[2], weight->ne[3]);
+
+            applied_lora_tensors.insert(lora_up_name);
+            applied_lora_tensors.insert(lora_down_name);
+            applied_lora_tensors.insert(alpha_name);
+            applied_lora_tensors.insert(scale_name);
+
+            // calc_scale
+            int64_t dim = lora_down->ne[lora_down->n_dims - 1];
+            if (lora_tensor_map.find(scale_name) != lora_tensor_map.end()) {
+                ggml_tensor* t = lora_tensor_map[scale_name];
+                scale = ggml_get_f32_1d(t, 0);
+            } else if (lora_tensor_map.find(alpha_name) != lora_tensor_map.end()) {
+                ggml_tensor* t = lora_tensor_map[alpha_name];
+                scale = ggml_get_f32_1d(t, 0) / dim;
+            }
+
+            // LOG_DEBUG("scale: %f %ld", scale, dim);
+
+            scale = scale * multiplier;
+
+            // apply
+            {
+                struct ggml_init_params params;
+                params.mem_size = ctx_size;
+                params.mem_buffer = mem_buffer;
+                params.no_alloc = false;
+                params.dynamic = false;
+
+                struct ggml_context* ctx = ggml_init(params);
+                if (!ctx) {
+                    LOG_ERROR("ggml_init() failed");
+                    free(mem_buffer);
+                    if (free_params_immediately) {
+                        remove_lora_params(lora_name);
+                    }
+                    return;
+                }
+
+                ggml_tensor* scale_factor = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 1);
+                ggml_set_f32_1d(scale_factor, 0, scale);
+                int64_t lora_up_size_0 = lora_up->ne[lora_up->n_dims - 1];
+                lora_up = ggml_reshape_2d(ctx, lora_up, ggml_nelements(lora_up) / lora_up_size_0, lora_up_size_0);
+                int64_t lora_down_size_0 = lora_down->ne[lora_down->n_dims - 1];
+                lora_down = ggml_reshape_2d(ctx, lora_down, ggml_nelements(lora_down) / lora_down_size_0, lora_down_size_0);
+
+                lora_down = ggml_cont(ctx, ggml_transpose(ctx, lora_down));
+
+                if (lora_down->type != GGML_TYPE_F32) {
+                    ggml_tensor* lora_down_f32 = ggml_new_tensor(ctx, GGML_TYPE_F32, lora_down->n_dims, lora_down->ne);
+                    lora_down = ggml_cpy_inplace(ctx, lora_down, lora_down_f32);
+                }
+
+                ggml_tensor* updown = ggml_mul_mat(ctx, lora_up, lora_down);
+                updown = ggml_cont(ctx, ggml_transpose(ctx, updown));
+                updown = ggml_reshape(ctx, updown, weight);
+
+                GGML_ASSERT(ggml_nelements(updown) == ggml_nelements(weight));
+
+                updown = ggml_scale_inplace(ctx, updown, scale_factor);
+                ggml_tensor* final_weight;
+                final_weight = ggml_add_inplace(ctx, weight, updown);
+                final_weight = ggml_cpy_inplace(ctx, final_weight, weight);
+
+                struct ggml_cgraph* graph = ggml_build_forward_ctx(ctx, final_weight);
+
+                ggml_graph_compute_with_ctx(ctx, graph, n_threads);
+
+                // LOG_INFO("network_name '%s' ggml_used_mem size = %.2fMB",
+                //           network_name.c_str(),
+                //           ggml_used_mem(ctx) / 1024.0 / 1024.0);
+
+                ggml_free(ctx);
+            }
+        }
+        free(mem_buffer);
+
+        for (auto& kv : lora_tensor_map) {
+            if (applied_lora_tensors.find(kv.first) == applied_lora_tensors.end()) {
+                LOG_WARN("unused lora tensor %s", kv.first.c_str());
+            }
+        }
+
+        if (free_params_immediately) {
+            remove_lora_params(lora_name);
+        }
+
+        int64_t t1 = ggml_time_ms();
+
+        LOG_INFO("apply lora '%s:%f' completed, taking %.2fs",
+                 lora_name.c_str(),
+                 multiplier,
+                 (t1 - t0) * 1.0f / 1000);
+    }
+
+    void apply_loras(const std::unordered_map<std::string, float>& lora_state) {
+        std::unordered_map<std::string, float> lora_state_diff;
+        for (auto& kv : lora_state) {
+            const std::string& lora_name = kv.first;
+            float multiplier = kv.second;
+
+            if (curr_lora_state.find(lora_name) != curr_lora_state.end()) {
+                float curr_multiplier = curr_lora_state[lora_name];
+                float multiplier_diff = multiplier - curr_multiplier;
+                if (multiplier_diff != 0.f) {
+                    lora_state_diff[lora_name] = multiplier_diff;
+                }
+            } else {
+                lora_state_diff[lora_name] = multiplier;
+            }
+        }
+
+        for (auto& kv : lora_state_diff) {
+            apply_lora(kv.first, kv.second);
+        }
+
+        curr_lora_state = lora_state;
+    }
+
     ggml_tensor* get_learned_condition(ggml_context* res_ctx, const std::string& text) {
         auto tokens_and_weights = cond_stage_model.tokenize(text,
                                                             cond_stage_model.text_model.max_position_embeddings,
@@ -4235,10 +4596,12 @@ class StableDiffusionGGML {
 StableDiffusion::StableDiffusion(int n_threads,
                                  bool vae_decode_only,
                                  bool free_params_immediately,
+                                 std::string lora_model_dir,
                                  RNGType rng_type) {
     sd = std::make_shared<StableDiffusionGGML>(n_threads,
                                                vae_decode_only,
                                                free_params_immediately,
+                                               lora_model_dir,
                                                rng_type);
 }
 
@@ -4246,8 +4609,8 @@ bool StableDiffusion::load_from_file(const std::string& file_path, Schedule s) {
     return sd->load_from_file(file_path, s);
 }
 
-std::vector<uint8_t> StableDiffusion::txt2img(const std::string& prompt,
-                                              const std::string& negative_prompt,
+std::vector<uint8_t> StableDiffusion::txt2img(std::string prompt,
+                                              std::string negative_prompt,
                                               float cfg_scale,
                                               int width,
                                               int height,
@@ -4272,13 +4635,28 @@ std::vector<uint8_t> StableDiffusion::txt2img(const std::string& prompt,
     }
     sd->rng->manual_seed(seed);
 
+    // extract and remote lora
+    auto result_pair = extract_and_remove_lora(prompt);
+    std::unordered_map<std::string, float> lora_f2m = result_pair.first;  // lora_name -> multiplier
+    for (auto& kv : lora_f2m) {
+        LOG_DEBUG("lora %s:%.2f", kv.first.c_str(), kv.second);
+    }
+    prompt = result_pair.second;
+    LOG_DEBUG("prompt after extract and remote lora: \"%s\"", prompt.c_str());
+
+    // load lora from file
     int64_t t0 = ggml_time_ms();
+    sd->apply_loras(lora_f2m);
+    int64_t t1 = ggml_time_ms();
+    LOG_INFO("apply_loras completed, taking %.2fs", (t1 - t0) * 1.0f / 1000);
+
+    t0 = ggml_time_ms();
     ggml_tensor* c = sd->get_learned_condition(ctx, prompt);
     struct ggml_tensor* uc = NULL;
     if (cfg_scale != 1.0) {
         uc = sd->get_learned_condition(ctx, negative_prompt);
     }
-    int64_t t1 = ggml_time_ms();
+    t1 = ggml_time_ms();
     LOG_INFO("get_learned_condition completed, taking %.2fs", (t1 - t0) * 1.0f / 1000);
 
     if (sd->free_params_immediately) {
@@ -4334,8 +4712,8 @@ std::vector<uint8_t> StableDiffusion::txt2img(const std::string& prompt,
 }
 
 std::vector<uint8_t> StableDiffusion::img2img(const std::vector<uint8_t>& init_img_vec,
-                                              const std::string& prompt,
-                                              const std::string& negative_prompt,
+                                              std::string prompt,
+                                              std::string negative_prompt,
                                               float cfg_scale,
                                               int width,
                                               int height,
@@ -4372,14 +4750,29 @@ std::vector<uint8_t> StableDiffusion::img2img(const std::vector<uint8_t>& init_i
     }
     sd->rng->manual_seed(seed);
 
+    // extract and remote lora
+    auto result_pair = extract_and_remove_lora(prompt);
+    std::unordered_map<std::string, float> lora_f2m = result_pair.first;  // lora_name -> multiplier
+    for (auto& kv : lora_f2m) {
+        LOG_DEBUG("lora %s:%.2f", kv.first.c_str(), kv.second);
+    }
+    prompt = result_pair.second;
+    LOG_DEBUG("prompt after extract and remote lora: \"%s\"", prompt.c_str());
+
+    // load lora from file
+    int64_t t0 = ggml_time_ms();
+    sd->apply_loras(lora_f2m);
+    int64_t t1 = ggml_time_ms();
+    LOG_INFO("apply_loras completed, taking %.2fs", (t1 - t0) * 1.0f / 1000);
+
     ggml_tensor* init_img = ggml_new_tensor_4d(ctx, GGML_TYPE_F32, width, height, 3, 1);
     image_vec_to_ggml(init_img_vec, init_img);
 
-    int64_t t0 = ggml_time_ms();
+    t0 = ggml_time_ms();
     ggml_tensor* moments = sd->encode_first_stage(ctx, init_img);
     ggml_tensor* init_latent = sd->get_first_stage_encoding(ctx, moments);
     // print_ggml_tensor(init_latent);
-    int64_t t1 = ggml_time_ms();
+    t1 = ggml_time_ms();
     LOG_INFO("encode_first_stage completed, taking %.2fs", (t1 - t0) * 1.0f / 1000);
 
     ggml_reset_curr_max_dynamic_size();  // reset counter

stable-diffusion.h

@@ -45,11 +45,12 @@ class StableDiffusion {
     StableDiffusion(int n_threads = -1,
                     bool vae_decode_only = false,
                     bool free_params_immediately = false,
+                    std::string lora_model_dir = "",
                     RNGType rng_type = STD_DEFAULT_RNG);
     bool load_from_file(const std::string& file_path, Schedule d = DEFAULT);
     std::vector<uint8_t> txt2img(
-        const std::string& prompt,
-        const std::string& negative_prompt,
+        std::string prompt,
+        std::string negative_prompt,
         float cfg_scale,
         int width,
         int height,
@@ -58,8 +59,8 @@ class StableDiffusion {
         int64_t seed);
     std::vector<uint8_t> img2img(
         const std::vector<uint8_t>& init_img,
-        const std::string& prompt,
-        const std::string& negative_prompt,
+        std::string prompt,
+        std::string negative_prompt,
         float cfg_scale,
         int width,
         int height,