speculative : add tree-based sampling example (#3624)

* sampling : one sequence per sampling context

ggml-ci

* speculative : add tree-based sampling support

ggml-ci

* speculative : reuse the n_parallel CLI param

* speculative : refactor sampling

* examples : fix build after sampling refactoring

ggml-ci

* batched : fix n_seq_id

* sampling : fix malloc

ggml-ci

* swift : fix build

ggml-ci

* swift : try to fix build

ggml-ci

* prompts : add assistant.txt

* common : add llama_batch_add() and llama_batch_clear() helpers

* speculative : minor refactor

ggml-ci

* minor : comments + rename

ggml-ci

* speculative : fix off-by-one for n_drafted

* speculative : fix the n_drafted fix + p constants

1 files changed, 10 insertions, 7 deletions

diff --git a/llama.h b/llama.h
index b13f2312..51010e03 100644
--- a/llama.h
+++ b/llama.h
@@ -133,11 +133,12 @@ extern "C" {
     typedef struct llama_batch {
         int32_t n_tokens;
 
-        llama_token  * token;
-        float        * embd;
-        llama_pos    * pos;
-        llama_seq_id * seq_id;
-        int8_t       * logits;
+        llama_token  *  token;
+        float        *  embd;
+        llama_pos    *  pos;
+        int32_t      *  n_seq_id;
+        llama_seq_id ** seq_id;
+        int8_t       *  logits;
 
         // NOTE: helpers for smooth API transition - can be deprecated in the future
         //       for future-proof code, use the above fields instead and ignore everything below
@@ -446,7 +447,8 @@ extern "C" {
                     llama_pos   pos_0,
                  llama_seq_id   seq_id);
 
-    // Allocates a batch of tokens on the heap
+    // Allocates a batch of tokens on the heap that can hold a maximum of n_tokens
+    // Each token can be assigned up to n_seq_max sequence ids
     // The batch has to be freed with llama_batch_free()
     // If embd != 0, llama_batch.embd will be allocated with size of n_tokens * embd * sizeof(float)
     // Otherwise, llama_batch.token will be allocated to store n_tokens llama_token
@@ -454,7 +456,8 @@ extern "C" {
     // All members are left uninitialized
     LLAMA_API struct llama_batch llama_batch_init(
             int32_t n_tokens,
-            int32_t embd);
+            int32_t embd,
+            int32_t n_seq_max);
 
     // Frees a batch of tokens allocated with llama_batch_init()
     LLAMA_API void llama_batch_free(struct llama_batch batch);