llama : add llama_chat_apply_template() (#5538)

* llama: add llama_chat_apply_template

* test-chat-template: remove dedundant vector

* chat_template: do not use std::string for buffer

* add clarification for llama_chat_apply_template

* llama_chat_apply_template: add zephyr template

* llama_chat_apply_template: correct docs

* llama_chat_apply_template: use term "chat" everywhere

* llama_chat_apply_template: change variable name to "tmpl"
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Xuan Son Nguyen 2024-02-19 09:23:37 +01:00 committed by GitHub
parent 3a9cb4ca64
commit 11b12de39b
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5 changed files with 211 additions and 0 deletions

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@ -867,3 +867,7 @@ tests/test-model-load-cancel: tests/test-model-load-cancel.cpp ggml.o llama.o te
tests/test-autorelease: tests/test-autorelease.cpp ggml.o llama.o tests/get-model.cpp $(COMMON_DEPS) $(OBJS)
$(CXX) $(CXXFLAGS) -c $< -o $(call GET_OBJ_FILE, $<)
$(CXX) $(CXXFLAGS) $(filter-out %.h $<,$^) $(call GET_OBJ_FILE, $<) -o $@ $(LDFLAGS)
tests/test-chat-template: tests/test-chat-template.cpp ggml.o llama.o $(COMMON_DEPS) $(OBJS)
$(CXX) $(CXXFLAGS) -c $< -o $(call GET_OBJ_FILE, $<)
$(CXX) $(CXXFLAGS) $(filter-out %.h $<,$^) $(call GET_OBJ_FILE, $<) -o $@ $(LDFLAGS)

117
llama.cpp
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@ -12508,6 +12508,123 @@ int32_t llama_token_to_piece(const struct llama_model * model, llama_token token
return 0;
}
// trim whitespace from the beginning and end of a string
static std::string trim(const std::string & str) {
size_t start = 0;
size_t end = str.size();
while (start < end && isspace(str[start])) {
start += 1;
}
while (end > start && isspace(str[end - 1])) {
end -= 1;
}
return str.substr(start, end - start);
}
// Simple version of "llama_apply_chat_template" that only works with strings
// This function uses heuristic checks to determine commonly used template. It is not a jinja parser.
static int32_t llama_chat_apply_template_internal(
const std::string & tmpl,
const std::vector<const llama_chat_message *> & chat,
std::string & dest, bool add_ass) {
// Taken from the research: https://github.com/ggerganov/llama.cpp/issues/5527
std::stringstream ss;
if (tmpl.find("<|im_start|>") != std::string::npos) {
// chatml template
for (auto message : chat) {
ss << "<|im_start|>" << message->role << "\n" << message->content << "<|im_end|>\n";
}
if (add_ass) {
ss << "<|im_start|>assistant\n";
}
} else if (tmpl.find("[INST]") != std::string::npos) {
// llama2 template and its variants
// [variant] support system message
bool support_system_message = tmpl.find("<<SYS>>") != std::string::npos;
// [variant] space before + after response
bool space_around_response = tmpl.find("' ' + eos_token") != std::string::npos;
// [variant] add BOS inside history
bool add_bos_inside_history = tmpl.find("bos_token + '[INST]") != std::string::npos;
// [variant] trim spaces from the input message
bool strip_message = tmpl.find("content.strip()") != std::string::npos;
// construct the prompt
bool is_inside_turn = true; // skip BOS at the beginning
ss << "[INST] ";
for (auto message : chat) {
std::string content = strip_message ? trim(message->content) : message->content;
std::string role(message->role);
if (!is_inside_turn) {
is_inside_turn = true;
ss << (add_bos_inside_history ? "<s>[INST] " : "[INST] ");
}
if (role == "system") {
if (support_system_message) {
ss << "<<SYS>>\n" << content << "\n<</SYS>>\n\n";
} else {
// if the model does not support system message, we still include it in the first message, but without <<SYS>>
ss << content << "\n";
}
} else if (role == "user") {
ss << content << " [/INST]";
} else {
ss << (space_around_response ? " " : "") << content << (space_around_response ? " " : "") << "</s>";
is_inside_turn = false;
}
}
// llama2 templates seem to not care about "add_generation_prompt"
} else if (tmpl.find("<|user|>") != std::string::npos) {
// zephyr template
for (auto message : chat) {
ss << "<|" << message->role << "|>" << "\n" << message->content << "<|endoftext|>\n";
}
if (add_ass) {
ss << "<|assistant|>\n";
}
} else {
// template not supported
return -1;
}
dest = ss.str();
return dest.size();
}
LLAMA_API int32_t llama_chat_apply_template(
const struct llama_model * model,
const char * tmpl,
const struct llama_chat_message * chat,
size_t n_msg,
bool add_ass,
char * buf,
int32_t length) {
std::string curr_tmpl(tmpl == nullptr ? "" : tmpl);
if (tmpl == nullptr) {
GGML_ASSERT(model != nullptr);
// load template from model
std::vector<char> model_template(2048, 0); // longest known template is about 1200 bytes
std::string template_key = "tokenizer.chat_template";
int32_t res = llama_model_meta_val_str(model, template_key.c_str(), model_template.data(), curr_tmpl.size());
if (res < 0) {
// worst case: there is no information about template, we will use chatml by default
curr_tmpl = "<|im_start|>"; // see llama_chat_apply_template_internal
} else {
curr_tmpl = std::string(model_template.data(), model_template.size());
}
}
// format the chat to string
std::vector<const llama_chat_message *> chat_vec;
chat_vec.resize(n_msg);
for (size_t i = 0; i < n_msg; i++) {
chat_vec[i] = &chat[i];
}
std::string formatted_chat;
int32_t res = llama_chat_apply_template_internal(curr_tmpl, chat_vec, formatted_chat, add_ass);
if (res < 0) {
return res;
}
strncpy(buf, formatted_chat.c_str(), length);
return res;
}
struct llama_timings llama_get_timings(struct llama_context * ctx) {
struct llama_timings result = {
/*.t_start_ms =*/ 1e-3 * ctx->t_start_us,

25
llama.h
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@ -305,6 +305,12 @@ extern "C" {
int32_t n_eval;
};
// used in chat template
typedef struct llama_chat_message {
const char * role;
const char * content;
} llama_chat_message;
// Helpers for getting default parameters
LLAMA_API struct llama_model_params llama_model_default_params(void);
LLAMA_API struct llama_context_params llama_context_default_params(void);
@ -699,6 +705,25 @@ extern "C" {
char * buf,
int32_t length);
/// Apply chat template. Inspired by hf apply_chat_template() on python.
/// Both "model" and "custom_template" are optional, but at least one is required. "custom_template" has higher precedence than "model"
/// NOTE: This function only support some known jinja templates. It is not a jinja parser.
/// @param tmpl A Jinja template to use for this chat. If this is nullptr, the models default chat template will be used instead.
/// @param chat Pointer to a list of multiple llama_chat_message
/// @param n_msg Number of llama_chat_message in this chat
/// @param add_ass Whether to end the prompt with the token(s) that indicate the start of an assistant message.
/// @param buf A buffer to hold the output formatted prompt. The recommended alloc size is 2 * (total number of characters of all messages)
/// @param length The size of the allocated buffer
/// @return The total number of bytes of the formatted prompt. If is it larger than the size of buffer, you may need to re-alloc it and then re-apply the template.
LLAMA_API int32_t llama_chat_apply_template(
const struct llama_model * model,
const char * tmpl,
const struct llama_chat_message * chat,
size_t n_msg,
bool add_ass,
char * buf,
int32_t length);
//
// Grammar
//

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@ -28,6 +28,7 @@ endfunction()
llama_build_and_test_executable(test-quantize-fns.cpp)
llama_build_and_test_executable(test-quantize-perf.cpp)
llama_build_and_test_executable(test-sampling.cpp)
llama_build_and_test_executable(test-chat-template.cpp)
llama_build_executable(test-tokenizer-0-llama.cpp)
llama_test_executable (test-tokenizer-0-llama test-tokenizer-0-llama.cpp ${CMAKE_CURRENT_SOURCE_DIR}/../models/ggml-vocab-llama.gguf)

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@ -0,0 +1,64 @@
#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#undef NDEBUG
#include <cassert>
#include "llama.h"
int main(void) {
llama_chat_message conversation[] = {
{"system", "You are a helpful assistant"},
{"user", "Hello"},
{"assistant", "Hi there"},
{"user", "Who are you"},
{"assistant", " I am an assistant "},
{"user", "Another question"},
};
size_t message_count = 6;
std::vector<std::string> templates = {
// teknium/OpenHermes-2.5-Mistral-7B
"{% for message in messages %}{{'<|im_start|>' + message['role'] + '\\n' + message['content'] + '<|im_end|>' + '\\n'}}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant\\n' }}{% endif %}",
// mistralai/Mistral-7B-Instruct-v0.2
"{{ bos_token }}{% for message in messages %}{% if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}{{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}{% endif %}{% if message['role'] == 'user' %}{{ '[INST] ' + message['content'] + ' [/INST]' }}{% elif message['role'] == 'assistant' %}{{ message['content'] + eos_token}}{% else %}{{ raise_exception('Only user and assistant roles are supported!') }}{% endif %}{% endfor %}",
// TheBloke/FusionNet_34Bx2_MoE-AWQ
"{%- for idx in range(0, messages|length) -%}\\n{%- if messages[idx]['role'] == 'user' -%}\\n{%- if idx > 1 -%}\\n{{- bos_token + '[INST] ' + messages[idx]['content'] + ' [/INST]' -}}\\n{%- else -%}\\n{{- messages[idx]['content'] + ' [/INST]' -}}\\n{%- endif -%}\\n{% elif messages[idx]['role'] == 'system' %}\\n{{- '[INST] <<SYS>>\\\\n' + messages[idx]['content'] + '\\\\n<</SYS>>\\\\n\\\\n' -}}\\n{%- elif messages[idx]['role'] == 'assistant' -%}\\n{{- ' ' + messages[idx]['content'] + ' ' + eos_token -}}\\n{% endif %}\\n{% endfor %}",
// bofenghuang/vigogne-2-70b-chat
"{{ bos_token }}{% if messages[0]['role'] == 'system' %}{% set loop_messages = messages[1:] %}{% set system_message = messages[0]['content'] %}{% elif true == true and not '<<SYS>>' in messages[0]['content'] %}{% set loop_messages = messages %}{% set system_message = 'Vous êtes Vigogne, un assistant IA créé par Zaion Lab. Vous suivez extrêmement bien les instructions. Aidez autant que vous le pouvez.' %}{% else %}{% set loop_messages = messages %}{% set system_message = false %}{% endif %}{% for message in loop_messages %}{% if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}{{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}{% endif %}{% if loop.index0 == 0 and system_message != false %}{% set content = '<<SYS>>\\\\n' + system_message + '\\\\n<</SYS>>\\\\n\\\\n' + message['content'] %}{% else %}{% set content = message['content'] %}{% endif %}{% if message['role'] == 'user' %}{{ '[INST] ' + content.strip() + ' [/INST]' }}{% elif message['role'] == 'system' %}{{ '<<SYS>>\\\\n' + content.strip() + '\\\\n<</SYS>>\\\\n\\\\n' }}{% elif message['role'] == 'assistant' %}{{ ' ' + content.strip() + ' ' + eos_token }}{% endif %}{% endfor %}",
};
std::vector<std::string> expected_substr = {
"<|im_start|>assistant\n I am an assistant <|im_end|>\n<|im_start|>user\nAnother question<|im_end|>\n<|im_start|>assistant",
"[/INST]Hi there</s>[INST] Who are you [/INST] I am an assistant </s>[INST] Another question [/INST]",
"</s><s>[INST] Who are you [/INST] I am an assistant </s><s>[INST] Another question [/INST]",
"[/INST] Hi there </s>[INST] Who are you [/INST] I am an assistant </s>[INST] Another question [/INST]",
};
std::vector<char> formatted_chat(1024);
int32_t res;
// test invalid chat template
res = llama_chat_apply_template(nullptr, "INVALID TEMPLATE", conversation, message_count, true, formatted_chat.data(), formatted_chat.size());
assert(res < 0);
for (size_t i = 0; i < templates.size(); i++) {
std::string custom_template = templates[i];
std::string substr = expected_substr[i];
formatted_chat.resize(1024);
res = llama_chat_apply_template(
nullptr,
custom_template.c_str(),
conversation,
message_count,
true,
formatted_chat.data(),
formatted_chat.size()
);
formatted_chat.resize(res);
std::string output(formatted_chat.data(), formatted_chat.size());
std::cout << output << "\n-------------------------\n";
// expect the "formatted_chat" to contain pre-defined strings
assert(output.find(substr) != std::string::npos);
}
return 0;
}