Add toolchain from agentic system here

toolchain/inference/generation.py

@@ -0,0 +1,298 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# This software may be used and distributed in accordance with the terms of the Llama 3 Community License Agreement.
+
+import json
+import os
+import sys
+import time
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Generator, List, Optional, TypedDict
+
+import torch
+import torch.nn.functional as F
+from fairscale.nn.model_parallel.initialize import (
+    get_model_parallel_rank,
+    initialize_model_parallel,
+    model_parallel_is_initialized,
+)
+from models.llama3.args import ModelArgs
+from models.llama3.chat_format import ChatFormat, ModelInput
+from models.llama3.datatypes import Message
+from models.llama3.model import Transformer
+from models.llama3.tokenizer import Tokenizer
+from termcolor import cprint
+
+
+@dataclass
+class TokenResult:
+    token: int
+    text: str
+    logprobs: Optional[List[float]] = None
+
+
+class CompletionPrediction(TypedDict, total=False):
+    generation: str
+    tokens: List[str]  # not required
+    logprobs: List[float]  # not required
+
+
+class Llama:
+    @staticmethod
+    def build(
+        ckpt_dir: str,
+        tokenizer_path: str,
+        max_seq_len: int,
+        max_batch_size: int,
+        model_parallel_size: Optional[int] = None,
+        seed: int = 1,
+    ) -> "Llama":
+        """
+        Build a Llama instance by initializing and loading a model checkpoint.
+
+        Args:
+            ckpt_dir (str): Path to the directory containing checkpoint files.
+            tokenizer_path (str): Path to the tokenizer file.
+            max_seq_len (int): Maximum sequence length for input text.
+            max_batch_size (int): Maximum batch size for inference.
+            model_parallel_size (Optional[int], optional): Number of model parallel processes.
+                If not provided, it's determined from the environment. Defaults to None.
+
+        Returns:
+            Llama: An instance of the Llama class with the loaded model and tokenizer.
+
+        Raises:
+            AssertionError: If there are no checkpoint files in the specified directory,
+                or if the model parallel size does not match the number of checkpoint files.
+
+        Note:
+            This method initializes the distributed process group, sets the device to CUDA,
+            and loads the pre-trained model and tokenizer.
+        """
+
+        if not torch.distributed.is_initialized():
+            torch.distributed.init_process_group("nccl")
+        if not model_parallel_is_initialized():
+            if model_parallel_size is None:
+                model_parallel_size = int(os.environ.get("WORLD_SIZE", 1))
+            initialize_model_parallel(model_parallel_size)
+
+        local_rank = int(os.environ.get("LOCAL_RANK", 0))
+        torch.cuda.set_device(local_rank)
+
+        # seed must be the same in all processes
+        torch.manual_seed(seed)
+
+        if local_rank > 0:
+            sys.stdout = open(os.devnull, "w")
+
+        start_time = time.time()
+        checkpoints = sorted(Path(ckpt_dir).glob("*.pth"))
+        assert len(checkpoints) > 0, f"no checkpoint files found in {ckpt_dir}"
+        assert model_parallel_size == len(
+            checkpoints
+        ), f"Loading a checkpoint for MP={len(checkpoints)} but world size is {model_parallel_size}"
+        ckpt_path = checkpoints[get_model_parallel_rank()]
+        checkpoint = torch.load(ckpt_path, map_location="cpu")
+        with open(Path(ckpt_dir) / "params.json", "r") as f:
+            params = json.loads(f.read())
+
+        # TODO(ashwin): this block is so we can load internal checkpoints without additional
+        # fuss. the final code should _not_ have this blurb
+        if "model" in params:
+            params = params["model"]
+
+        model_args: ModelArgs = ModelArgs(
+            max_seq_len=max_seq_len,
+            max_batch_size=max_batch_size,
+            **params,
+        )
+        tokenizer = Tokenizer(model_path=tokenizer_path)
+
+        assert (
+            model_args.vocab_size == tokenizer.n_words
+        ), f"model_args vocab = {model_args.vocab_size} but tokenizer vocab = {tokenizer.n_words}"
+        if torch.cuda.is_bf16_supported():
+            torch.set_default_tensor_type(torch.cuda.BFloat16Tensor)
+        else:
+            torch.set_default_tensor_type(torch.cuda.HalfTensor)
+
+        model = Transformer(model_args)
+        model.load_state_dict(checkpoint, strict=False)
+        print(f"Loaded in {time.time() - start_time:.2f} seconds")
+
+        return Llama(model, tokenizer, model_args)
+
+    def __init__(self, model: Transformer, tokenizer: Tokenizer, args: ModelArgs):
+        self.args = args
+        self.model = model
+        self.tokenizer = tokenizer
+        self.formatter = ChatFormat(tokenizer)
+
+    @torch.inference_mode()
+    def generate(
+        self,
+        model_input: ModelInput,
+        max_gen_len: int,
+        temperature: float = 0.6,
+        top_p: float = 0.9,
+        logprobs: bool = False,
+        echo: bool = False,
+        include_stop_token: bool = False,
+    ) -> Generator:
+        params = self.model.params
+
+        # cprint("Input to model -> " + self.tokenizer.decode(model_input.tokens), "red")
+        prompt_tokens = [model_input.tokens]
+
+        bsz = 1
+        assert bsz <= params.max_batch_size, (bsz, params.max_batch_size)
+
+        min_prompt_len = min(len(t) for t in prompt_tokens)
+        max_prompt_len = max(len(t) for t in prompt_tokens)
+
+        if max_prompt_len >= params.max_seq_len:
+            cprint(
+                f"Out of token budget {max_prompt_len} vs {params.max_seq_len}", "red"
+            )
+            return
+
+        total_len = min(max_gen_len + max_prompt_len, params.max_seq_len)
+        pad_id = self.tokenizer.pad_id
+        tokens = torch.full((bsz, total_len), pad_id, dtype=torch.long, device="cuda")
+        for k, t in enumerate(prompt_tokens):
+            tokens[k, : len(t)] = torch.tensor(t, dtype=torch.long, device="cuda")
+        if logprobs:
+            token_logprobs = torch.zeros_like(tokens, dtype=torch.float)
+
+        prev_pos = 0
+        eos_reached = torch.tensor([False] * bsz, device="cuda")
+        input_text_mask = tokens != pad_id
+        if min_prompt_len == total_len:
+            # TODO(ashwin): unify this branch with the one below and figure out multimodal crap
+            logits = self.model.forward(tokens, prev_pos)
+            token_logprobs = -F.cross_entropy(
+                input=logits.transpose(1, 2),
+                target=tokens,
+                reduction="none",
+                ignore_index=pad_id,
+            )
+
+        stop_tokens = torch.tensor(self.tokenizer.stop_tokens)
+
+        for cur_pos in range(min_prompt_len, total_len):
+            logits = self.model.forward(tokens[:, prev_pos:cur_pos], prev_pos)
+
+            if temperature > 0:
+                probs = torch.softmax(logits[:, -1] / temperature, dim=-1)
+                next_token = sample_top_p(probs, top_p)
+            else:
+                next_token = torch.argmax(logits[:, -1], dim=-1)
+
+            next_token = next_token.reshape(-1)
+            # only replace token if prompt has already been generated
+            next_token = torch.where(
+                input_text_mask[:, cur_pos], tokens[:, cur_pos], next_token
+            )
+            tokens[:, cur_pos] = next_token
+
+            target = tokens[:, prev_pos + 1 : cur_pos + 1]
+            if logprobs:
+                token_logprobs[:, prev_pos + 1 : cur_pos + 1] = -F.cross_entropy(
+                    input=logits.transpose(1, 2),
+                    target=tokens[:, prev_pos + 1 : cur_pos + 1],
+                    reduction="none",
+                    ignore_index=pad_id,
+                )
+            eos_reached |= (~input_text_mask[:, cur_pos]) & (
+                torch.isin(next_token, stop_tokens)
+            )
+            yield TokenResult(
+                token=next_token[0].item(),
+                text=self.tokenizer.decode(next_token.tolist()),
+                logprobs=(
+                    token_logprobs[:, prev_pos + 1 : cur_pos + 1][0].tolist()
+                    if logprobs
+                    else None
+                ),
+            )
+
+            prev_pos = cur_pos
+            if all(eos_reached):
+                break
+
+    def text_completion(
+        self,
+        prompt: str,
+        temperature: float = 0.6,
+        top_p: float = 0.9,
+        max_gen_len: Optional[int] = None,
+        logprobs: bool = False,
+        echo: bool = False,
+    ) -> Generator:
+        if (
+            max_gen_len is None
+            or max_gen_len == 0
+            or max_gen_len >= self.model.params.max_seq_len
+        ):
+            max_gen_len = self.model.params.max_seq_len - 1
+
+        prompt_tokens = self.tokenizer.encode(x, bos=True, eos=False)
+
+        yield from self.generate(
+            model_input=ModelInput(tokens=prompt_tokens),
+            max_gen_len=max_gen_len,
+            temperature=temperature,
+            top_p=top_p,
+            logprobs=logprobs,
+            echo=echo,
+        )
+
+    def chat_completion(
+        self,
+        messages: List[Message],
+        temperature: float = 0.6,
+        top_p: float = 0.9,
+        max_gen_len: Optional[int] = None,
+        logprobs: bool = False,
+    ) -> Generator:
+        if (
+            max_gen_len is None
+            or max_gen_len == 0
+            or max_gen_len >= self.model.params.max_seq_len
+        ):
+            max_gen_len = self.model.params.max_seq_len - 1
+
+        yield from self.generate(
+            model_input=self.formatter.encode_dialog_prompt(messages),
+            max_gen_len=max_gen_len,
+            temperature=temperature,
+            top_p=top_p,
+            logprobs=logprobs,
+            include_stop_token=True,
+        )
+
+
+def sample_top_p(probs, p):
+    """
+    Perform top-p (nucleus) sampling on a probability distribution.
+
+    Args:
+        probs (torch.Tensor): Probability distribution tensor.
+        p (float): Probability threshold for top-p sampling.
+
+    Returns:
+        torch.Tensor: Sampled token indices.
+
+    Note:
+        Top-p sampling selects the smallest set of tokens whose cumulative probability mass
+        exceeds the threshold p. The distribution is renormalized based on the selected tokens.
+    """
+    probs_sort, probs_idx = torch.sort(probs, dim=-1, descending=True)
+    probs_sum = torch.cumsum(probs_sort, dim=-1)
+    mask = probs_sum - probs_sort > p
+    probs_sort[mask] = 0.0
+    probs_sort.div_(probs_sort.sum(dim=-1, keepdim=True))
+    next_token = torch.multinomial(probs_sort, num_samples=1)
+    next_token = torch.gather(probs_idx, -1, next_token)
+    return next_token