Add LoRA support (#820)

llama.h

@@ -96,6 +96,18 @@ extern "C" {
             const char * fname_out,
       enum llama_ftype   ftype);
 
+    // Apply a LoRA adapter to a loaded model
+    // path_base_model is the path to a higher quality model to use as a base for
+    // the layers modified by the adapter. Can be NULL to use the current loaded model.
+    // The model needs to be reloaded before applying a new adapter, otherwise the adapter
+    // will be applied on top of the previous one
+    // Returns 0 on success
+    LLAMA_API int llama_apply_lora_from_file(
+            struct llama_context * ctx,
+                      const char * path_lora,
+                      const char * path_base_model,
+                             int   n_threads);
+
     // Returns the KV cache that will contain the context for the
     // ongoing prediction with the model.
     LLAMA_API const uint8_t * llama_get_kv_cache(struct llama_context * ctx);