import os import sys import uuid import time import math import multiprocessing from typing import List, Optional, Union, Generator, Sequence, Iterator from collections import deque from . import llama_cpp from .llama_types import * class LlamaCache: """Cache for a llama.cpp model. NOTE: This implementation currently only tells the Llama class to avoid reprocessing bytes and continue from the last completion. It does not actually cache the results.""" pass class Llama: """High-level Python wrapper for a llama.cpp model.""" def __init__( self, model_path: str, # NOTE: These parameters are likely to change in the future. n_ctx: int = 512, n_parts: int = -1, seed: int = 1337, f16_kv: bool = True, logits_all: bool = False, vocab_only: bool = False, use_mmap: bool = True, use_mlock: bool = False, embedding: bool = False, n_threads: Optional[int] = None, n_batch: int = 8, last_n_tokens_size: int = 64, lora_base: Optional[str] = None, lora_path: Optional[str] = None, verbose: bool = True, ): """Load a llama.cpp model from `model_path`. Args: model_path: Path to the model. n_ctx: Maximum context size. n_parts: Number of parts to split the model into. If -1, the number of parts is automatically determined. seed: Random seed. 0 for random. f16_kv: Use half-precision for key/value cache. logits_all: Return logits for all tokens, not just the last token. vocab_only: Only load the vocabulary no weights. use_mmap: Use mmap if possible. use_mlock: Force the system to keep the model in RAM. embedding: Embedding mode only. n_threads: Number of threads to use. If None, the number of threads is automatically determined. n_batch: Maximum number of prompt tokens to batch together when calling llama_eval. last_n_tokens_size: Maximum number of tokens to keep in the last_n_tokens deque. lora_base: Optional path to base model, useful if using a quantized base model and you want to apply LoRA to an f16 model. lora_path: Path to a LoRA file to apply to the model. verbose: Print verbose output to stderr. Raises: ValueError: If the model path does not exist. Returns: A Llama instance. """ self.verbose = verbose self.model_path = model_path self.params = llama_cpp.llama_context_default_params() self.params.n_ctx = n_ctx self.params.n_parts = n_parts self.params.seed = seed self.params.f16_kv = f16_kv self.params.logits_all = logits_all self.params.vocab_only = vocab_only self.params.use_mmap = use_mmap self.params.use_mlock = use_mlock self.params.embedding = embedding self.last_n_tokens_size = last_n_tokens_size self.last_n_tokens_data = deque( [llama_cpp.llama_token(0)] * self.last_n_tokens_size, maxlen=self.last_n_tokens_size, ) self.tokens_consumed = 0 self.tokens: List[llama_cpp.llama_token] = [] self.n_batch = min(n_ctx, n_batch) self.n_tokens = 0 self.n_past = 0 self.all_logits: List[List[float]] = [] # TODO: Use an array instead of a list. ### HACK: This is a hack to work around the fact that the llama.cpp API does not yet support ### saving and restoring state, this allows us to continue a completion if the last ### completion_bytes is a prefix to the prompt passed in. However this is actually incorrect ### because it does not take into account stop tokens which have been processed by the model. self._completion_bytes: List[bytes] = [] self._cache: Optional[LlamaCache] = None ### self.n_threads = n_threads or max(multiprocessing.cpu_count() // 2, 1) if not os.path.exists(model_path): raise ValueError(f"Model path does not exist: {model_path}") self.ctx = llama_cpp.llama_init_from_file( self.model_path.encode("utf-8"), self.params ) self.lora_base = None self.lora_path = None if lora_path: self.lora_base = lora_base # Use lora_base if set otherwise revert to using model_path. lora_base = lora_base if lora_base is not None else model_path self.lora_path = lora_path if llama_cpp.llama_apply_lora_from_file( self.ctx, lora_path.encode("utf-8"), lora_base.encode("utf-8"), llama_cpp.c_int(self.n_threads), ): raise RuntimeError(f"Failed to apply LoRA from lora path: {lora_path} to base path: {lora_base}") if self.verbose: print(llama_cpp.llama_print_system_info().decode("utf-8"), file=sys.stderr) def tokenize(self, text: bytes) -> List[llama_cpp.llama_token]: """Tokenize a string. Args: text: The utf-8 encoded string to tokenize. Raises: RuntimeError: If the tokenization failed. Returns: A list of tokens. """ assert self.ctx is not None n_ctx = llama_cpp.llama_n_ctx(self.ctx) tokens = (llama_cpp.llama_token * int(n_ctx))() n_tokens = llama_cpp.llama_tokenize( self.ctx, text, tokens, n_ctx, llama_cpp.c_bool(True), ) if int(n_tokens) < 0: raise RuntimeError(f'Failed to tokenize: text="{text}" n_tokens={n_tokens}') return list(tokens[:n_tokens]) def detokenize(self, tokens: List[llama_cpp.llama_token]) -> bytes: """Detokenize a list of tokens. Args: tokens: The list of tokens to detokenize. Returns: The detokenized string. """ assert self.ctx is not None output = b"" for token in tokens: output += llama_cpp.llama_token_to_str(self.ctx, token) return output def set_cache(self, cache: Optional[LlamaCache]): """Set the cache. Args: cache: The cache to set. """ self._cache = cache def reset(self): """Reset the model state.""" self.last_n_tokens_data.extend( [llama_cpp.llama_token(0)] * self.last_n_tokens_size ) self.tokens_consumed = 0 self.tokens.clear() self.n_tokens = 0 self.n_past = 0 self.all_logits.clear() def eval(self, tokens: Sequence[llama_cpp.llama_token]): """Evaluate a list of tokens. Args: tokens: The list of tokens to evaluate. """ assert self.ctx is not None n_ctx = int(llama_cpp.llama_n_ctx(self.ctx)) for i in range(0, len(tokens), self.n_batch): batch = tokens[i : min(len(tokens), i + self.n_batch)] self.n_past = min(n_ctx - len(batch), self.tokens_consumed) self.n_tokens = len(batch) return_code = llama_cpp.llama_eval( ctx=self.ctx, tokens=(llama_cpp.llama_token * len(batch))(*batch), n_tokens=llama_cpp.c_int(self.n_tokens), n_past=llama_cpp.c_int(self.n_past), n_threads=llama_cpp.c_int(self.n_threads), ) if int(return_code) != 0: raise RuntimeError(f"llama_eval returned {return_code}") self.tokens.extend(batch) self.last_n_tokens_data.extend(batch) self.tokens_consumed += len(batch) if self.params.logits_all: self.all_logits.extend(self._logits()) def _logits(self) -> List[List[float]]: """Return the logits from the last call to llama_eval.""" assert self.ctx is not None n_vocab = llama_cpp.llama_n_vocab(self.ctx) cols = int(n_vocab) rows = self.n_tokens if self.params.logits_all else 1 logits_view = llama_cpp.llama_get_logits(self.ctx) logits = [[logits_view[i * cols + j] for j in range(cols)] for i in range(rows)] return logits def sample( self, top_k: int, top_p: float, temp: float, repeat_penalty: float, ): """Sample a token from the model. Args: top_k: The top-k sampling parameter. top_p: The top-p sampling parameter. temp: The temperature parameter. repeat_penalty: The repeat penalty parameter. Returns: The sampled token. """ assert self.ctx is not None return llama_cpp.llama_sample_top_p_top_k( ctx=self.ctx, last_n_tokens_data=(llama_cpp.llama_token * self.last_n_tokens_size)( *self.last_n_tokens_data ), last_n_tokens_size=llama_cpp.c_int(self.last_n_tokens_size), top_k=llama_cpp.c_int(top_k), top_p=llama_cpp.c_float(top_p), temp=llama_cpp.c_float(temp), repeat_penalty=llama_cpp.c_float(repeat_penalty), ) def generate( self, tokens: Sequence[llama_cpp.llama_token], top_k: int, top_p: float, temp: float, repeat_penalty: float, reset: bool = True, ) -> Generator[ llama_cpp.llama_token, Optional[Sequence[llama_cpp.llama_token]], None ]: """Create a generator of tokens from a prompt. Examples: >>> llama = Llama("models/ggml-7b.bin") >>> tokens = llama.tokenize(b"Hello, world!") >>> for token in llama.generate(tokens, top_k=40, top_p=0.95, temp=1.0, repeat_penalty=1.1): ... print(llama.detokenize([token])) Args: tokens: The prompt tokens. top_k: The top-k sampling parameter. top_p: The top-p sampling parameter. temp: The temperature parameter. repeat_penalty: The repeat penalty parameter. reset: Whether to reset the model state. Yields: The generated tokens. """ assert self.ctx is not None ### HACK if ( reset and self._cache and len(self.tokens) > 0 and self.tokens == tokens[: len(self.tokens)] ): if self.verbose: print("generate cache hit", file=sys.stderr) reset = False tokens = tokens[len(self.tokens) :] ### if reset: self.reset() while True: self.eval(tokens) token = self.sample( top_k=top_k, top_p=top_p, temp=temp, repeat_penalty=repeat_penalty, ) tokens_or_none = yield token tokens = [token] if tokens_or_none is not None: tokens.extend(tokens_or_none) def create_embedding(self, input: str) -> Embedding: """Embed a string. Args: input: The utf-8 encoded string to embed. Returns: An embedding object. """ assert self.ctx is not None if self.params.embedding == False: raise RuntimeError( "Llama model must be created with embedding=True to call this method" ) if self.verbose: llama_cpp.llama_reset_timings(self.ctx) tokens = self.tokenize(input.encode("utf-8")) self.reset() self.eval(tokens) n_tokens = len(tokens) embedding = llama_cpp.llama_get_embeddings(self.ctx)[ : llama_cpp.llama_n_embd(self.ctx) ] if self.verbose: llama_cpp.llama_print_timings(self.ctx) return { "object": "list", "data": [ { "object": "embedding", "embedding": embedding, "index": 0, } ], "model": self.model_path, "usage": { "prompt_tokens": n_tokens, "total_tokens": n_tokens, }, } def embed(self, input: str) -> List[float]: """Embed a string. Args: input: The utf-8 encoded string to embed. Returns: A list of embeddings """ return list(map(float, self.create_embedding(input)["data"][0]["embedding"])) def _create_completion( self, prompt: str, suffix: Optional[str] = None, max_tokens: int = 16, temperature: float = 0.8, top_p: float = 0.95, logprobs: Optional[int] = None, echo: bool = False, stop: Optional[List[str]] = [], repeat_penalty: float = 1.1, top_k: int = 40, stream: bool = False, ) -> Union[Iterator[Completion], Iterator[CompletionChunk]]: assert self.ctx is not None completion_id: str = f"cmpl-{str(uuid.uuid4())}" created: int = int(time.time()) completion_tokens: List[llama_cpp.llama_token] = [] # Add blank space to start of prompt to match OG llama tokenizer prompt_tokens: List[llama_cpp.llama_token] = self.tokenize( b" " + prompt.encode("utf-8") ) text: bytes = b"" returned_characters: int = 0 stop = stop if stop is not None else [] if self.verbose: llama_cpp.llama_reset_timings(self.ctx) if len(prompt_tokens) + max_tokens > int(llama_cpp.llama_n_ctx(self.ctx)): raise ValueError( f"Requested tokens exceed context window of {llama_cpp.llama_n_ctx(self.ctx)}" ) if stop != []: stop_sequences = [s.encode("utf-8") for s in stop] else: stop_sequences = [] if logprobs is not None and self.params.logits_all is False: raise ValueError( "logprobs is not supported for models created with logits_all=False" ) ### HACK reset: bool = True _prompt: bytes = prompt.encode("utf-8") _completion: bytes = b"".join(self._completion_bytes) if len(_completion) and self._cache and _prompt.startswith(_completion): if self.verbose: print("completion cache hit", file=sys.stderr) reset = False _prompt = _prompt[len(_completion) :] prompt_tokens = self.tokenize(b" " + _prompt) self._completion_bytes.append(_prompt) else: self._completion_bytes = [prompt.encode("utf-8")] ### finish_reason = "length" for token in self.generate( prompt_tokens, top_k=top_k, top_p=top_p, temp=temperature, repeat_penalty=repeat_penalty, reset=reset, ): if token == llama_cpp.llama_token_eos(): text = self.detokenize(completion_tokens) finish_reason = "stop" break completion_tokens.append(token) all_text = self.detokenize(completion_tokens) any_stop = [s for s in stop_sequences if s in all_text] if len(any_stop) > 0: first_stop = any_stop[0] text = all_text[: all_text.index(first_stop)] finish_reason = "stop" break if stream: start = returned_characters longest = 0 # We want to avoid yielding any characters from # the generated text if they are part of a stop # sequence. for s in stop_sequences: for i in range(len(s), 0, -1): if all_text.endswith(s[:i]): if i > longest: longest = i break text = all_text[: len(all_text) - longest] returned_characters += len(text[start:]) ### HACK self._completion_bytes.append(text[start:]) ### yield { "id": completion_id, "object": "text_completion", "created": created, "model": self.model_path, "choices": [ { "text": text[start:].decode("utf-8"), "index": 0, "logprobs": None, "finish_reason": None, } ], } if len(completion_tokens) >= max_tokens: text = self.detokenize(completion_tokens) finish_reason = "length" break if stream: ### HACK self._completion_bytes.append(text[returned_characters:]) ### yield { "id": completion_id, "object": "text_completion", "created": created, "model": self.model_path, "choices": [ { "text": text[returned_characters:].decode("utf-8"), "index": 0, "logprobs": None, "finish_reason": finish_reason, } ], } return ### HACK self._completion_bytes.append(text) ### text_str = text.decode("utf-8") if echo: text_str = prompt + text_str if suffix is not None: text_str = text_str + suffix logprobs_or_none: Optional[CompletionLogprobs] = None if logprobs is not None: text_offset = 0 text_offsets: List[int] = [] token_logprobs: List[float] = [] tokens: List[str] = [] top_logprobs: List[Dict[str, float]] = [] all_tokens = prompt_tokens + completion_tokens all_token_strs = [ self.detokenize([token]).decode("utf-8") for token in all_tokens ] all_logprobs = [ [Llama.logit_to_logprob(logit) for logit in row] for row in self.all_logits ] for token, token_str, logprobs_token in zip( all_tokens, all_token_strs, all_logprobs ): text_offsets.append(text_offset) text_offset += len(token_str) tokens.append(token_str) sorted_logprobs = list( sorted( zip(logprobs_token, range(len(logprobs_token))), reverse=True ) ) token_logprobs.append(sorted_logprobs[int(token)][0]) top_logprob = { self.detokenize([llama_cpp.llama_token(i)]).decode("utf-8"): logprob for logprob, i in sorted_logprobs[:logprobs] } top_logprob.update({token_str: sorted_logprobs[int(token)][0]}) top_logprobs.append(top_logprob) logprobs_or_none = { "tokens": tokens, "text_offset": text_offsets, "token_logprobs": token_logprobs, "top_logprobs": top_logprobs, } if self.verbose: llama_cpp.llama_print_timings(self.ctx) yield { "id": completion_id, "object": "text_completion", "created": created, "model": self.model_path, "choices": [ { "text": text_str, "index": 0, "logprobs": logprobs_or_none, "finish_reason": finish_reason, } ], "usage": { "prompt_tokens": len(prompt_tokens), "completion_tokens": len(completion_tokens), "total_tokens": len(prompt_tokens) + len(completion_tokens), }, } def create_completion( self, prompt: str, suffix: Optional[str] = None, max_tokens: int = 128, temperature: float = 0.8, top_p: float = 0.95, logprobs: Optional[int] = None, echo: bool = False, stop: Optional[List[str]] = [], repeat_penalty: float = 1.1, top_k: int = 40, stream: bool = False, ) -> Union[Completion, Iterator[CompletionChunk]]: """Generate text from a prompt. Args: prompt: The prompt to generate text from. suffix: A suffix to append to the generated text. If None, no suffix is appended. max_tokens: The maximum number of tokens to generate. temperature: The temperature to use for sampling. top_p: The top-p value to use for sampling. logprobs: The number of logprobs to return. If None, no logprobs are returned. echo: Whether to echo the prompt. stop: A list of strings to stop generation when encountered. repeat_penalty: The penalty to apply to repeated tokens. top_k: The top-k value to use for sampling. stream: Whether to stream the results. Raises: ValueError: If the requested tokens exceed the context window. RuntimeError: If the prompt fails to tokenize or the model fails to evaluate the prompt. Returns: Response object containing the generated text. """ completion_or_chunks = self._create_completion( prompt=prompt, suffix=suffix, max_tokens=max_tokens, temperature=temperature, top_p=top_p, logprobs=logprobs, echo=echo, stop=stop, repeat_penalty=repeat_penalty, top_k=top_k, stream=stream, ) if stream: chunks: Iterator[CompletionChunk] = completion_or_chunks return chunks completion: Completion = next(completion_or_chunks) # type: ignore return completion def __call__( self, prompt: str, suffix: Optional[str] = None, max_tokens: int = 128, temperature: float = 0.8, top_p: float = 0.95, logprobs: Optional[int] = None, echo: bool = False, stop: Optional[List[str]] = [], repeat_penalty: float = 1.1, top_k: int = 40, stream: bool = False, ) -> Union[Completion, Iterator[CompletionChunk]]: """Generate text from a prompt. Args: prompt: The prompt to generate text from. suffix: A suffix to append to the generated text. If None, no suffix is appended. max_tokens: The maximum number of tokens to generate. temperature: The temperature to use for sampling. top_p: The top-p value to use for sampling. logprobs: The number of logprobs to return. If None, no logprobs are returned. echo: Whether to echo the prompt. stop: A list of strings to stop generation when encountered. repeat_penalty: The penalty to apply to repeated tokens. top_k: The top-k value to use for sampling. stream: Whether to stream the results. Raises: ValueError: If the requested tokens exceed the context window. RuntimeError: If the prompt fails to tokenize or the model fails to evaluate the prompt. Returns: Response object containing the generated text. """ return self.create_completion( prompt=prompt, suffix=suffix, max_tokens=max_tokens, temperature=temperature, top_p=top_p, logprobs=logprobs, echo=echo, stop=stop, repeat_penalty=repeat_penalty, top_k=top_k, stream=stream, ) def _convert_text_completion_to_chat( self, completion: Completion ) -> ChatCompletion: return { "id": "chat" + completion["id"], "object": "chat.completion", "created": completion["created"], "model": completion["model"], "choices": [ { "index": 0, "message": { "role": "assistant", "content": completion["choices"][0]["text"], }, "finish_reason": completion["choices"][0]["finish_reason"], } ], "usage": completion["usage"], } def _convert_text_completion_chunks_to_chat( self, chunks: Iterator[CompletionChunk], ) -> Iterator[ChatCompletionChunk]: for i, chunk in enumerate(chunks): if i == 0: yield { "id": "chat" + chunk["id"], "model": chunk["model"], "created": chunk["created"], "object": "chat.completion.chunk", "choices": [ { "index": 0, "delta": { "role": "assistant", }, "finish_reason": None, } ], } yield { "id": "chat" + chunk["id"], "model": chunk["model"], "created": chunk["created"], "object": "chat.completion.chunk", "choices": [ { "index": 0, "delta": { "content": chunk["choices"][0]["text"], }, "finish_reason": chunk["choices"][0]["finish_reason"], } ], } def create_chat_completion( self, messages: List[ChatCompletionMessage], temperature: float = 0.2, top_p: float = 0.95, top_k: int = 40, stream: bool = False, stop: Optional[List[str]] = [], max_tokens: int = 256, repeat_penalty: float = 1.1, ) -> Union[ChatCompletion, Iterator[ChatCompletionChunk]]: """Generate a chat completion from a list of messages. Args: messages: A list of messages to generate a response for. temperature: The temperature to use for sampling. top_p: The top-p value to use for sampling. top_k: The top-k value to use for sampling. stream: Whether to stream the results. stop: A list of strings to stop generation when encountered. max_tokens: The maximum number of tokens to generate. repeat_penalty: The penalty to apply to repeated tokens. Returns: Generated chat completion or a stream of chat completion chunks. """ stop = stop if stop is not None else [] chat_history = "".join( f'### {"Human" if message["role"] == "user" else "Assistant"}:{message["content"]}' for message in messages ) PROMPT = chat_history + "### Assistant:" PROMPT_STOP = ["### Assistant:", "### Human:"] completion_or_chunks = self( prompt=PROMPT, stop=PROMPT_STOP + stop, temperature=temperature, top_p=top_p, top_k=top_k, stream=stream, max_tokens=max_tokens, repeat_penalty=repeat_penalty, ) if stream: chunks: Iterator[CompletionChunk] = completion_or_chunks # type: ignore return self._convert_text_completion_chunks_to_chat(chunks) else: completion: Completion = completion_or_chunks # type: ignore return self._convert_text_completion_to_chat(completion) def __del__(self): if self.ctx is not None: llama_cpp.llama_free(self.ctx) self.ctx = None def __getstate__(self): return dict( verbose=self.verbose, model_path=self.model_path, n_ctx=self.params.n_ctx, n_parts=self.params.n_parts, seed=self.params.seed, f16_kv=self.params.f16_kv, logits_all=self.params.logits_all, vocab_only=self.params.vocab_only, use_mmap=self.params.use_mmap, use_mlock=self.params.use_mlock, embedding=self.params.embedding, last_n_tokens_size=self.last_n_tokens_size, n_batch=self.n_batch, n_threads=self.n_threads, lora_base=self.lora_base, lora_path=self.lora_path, ) def __setstate__(self, state): self.__init__( model_path=state["model_path"], n_ctx=state["n_ctx"], n_parts=state["n_parts"], seed=state["seed"], f16_kv=state["f16_kv"], logits_all=state["logits_all"], vocab_only=state["vocab_only"], use_mmap=state["use_mmap"], use_mlock=state["use_mlock"], embedding=state["embedding"], n_threads=state["n_threads"], n_batch=state["n_batch"], last_n_tokens_size=state["last_n_tokens_size"], lora_base=state["lora_base"], lora_path=state["lora_path"], verbose=state["verbose"], ) @staticmethod def token_eos() -> llama_cpp.llama_token: """Return the end-of-sequence token.""" return llama_cpp.llama_token_eos() @staticmethod def token_bos() -> llama_cpp.llama_token: """Return the beginning-of-sequence token.""" return llama_cpp.llama_token_bos() @staticmethod def logit_to_logprob(x: float) -> float: return math.log(1.0 + math.exp(x))