Demo equivalence - tmp

llmc_py/prompts.json

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+{
+    "prompts": [
+      "Clearly, the meaning of life is",
+      "Simply put, the theory of relativity states that",
+      "The repo llm.c on GitHub is",
+      "Translate English to French:\n\nsea otter => loutre de mer\npeppermint => menthe poivrée\nplush girafe => girafe peluche\ncheese =>"
+    ]
+  }

llmc_py/rope.py

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+# From: https://github.com/meta-llama/llama-models/blob/main/models/llama3_1/api/model.py
+
+import math
+from typing import Tuple
+import torch
+
+def reshape_for_broadcast(freqs_cis: torch.Tensor, x: torch.Tensor):
+    ndim = x.ndim
+    assert 0 <= 1 < ndim
+    assert freqs_cis.shape == (x.shape[1], x.shape[-1])
+    shape = [d if i == 1 or i == ndim - 1 else 1 for i, d in enumerate(x.shape)]
+    return freqs_cis.view(*shape)
+
+def apply_scaling(freqs: torch.Tensor):
+    # Values obtained from grid search
+    scale_factor = 8
+    low_freq_factor = 1
+    high_freq_factor = 4
+    old_context_len = 8192  # original llama3 length
+
+    low_freq_wavelen = old_context_len / low_freq_factor
+    high_freq_wavelen = old_context_len / high_freq_factor
+    new_freqs = []
+    for freq in freqs:
+        wavelen = 2 * math.pi / freq
+        if wavelen < high_freq_wavelen:
+            new_freqs.append(freq)
+        elif wavelen > low_freq_wavelen:
+            new_freqs.append(freq / scale_factor)
+        else:
+            assert low_freq_wavelen != high_freq_wavelen
+            smooth = (old_context_len / wavelen - low_freq_factor) / (
+                high_freq_factor - low_freq_factor
+            )
+            new_freqs.append((1 - smooth) * freq / scale_factor + smooth * freq)
+    return torch.tensor(new_freqs, dtype=freqs.dtype, device=freqs.device)
+
+def apply_rotary_emb(
+    xq: torch.Tensor,
+    xk: torch.Tensor,
+    freqs_cis: torch.Tensor,
+) -> Tuple[torch.Tensor, torch.Tensor]:
+    xq_ = torch.view_as_complex(xq.float().reshape(*xq.shape[:-1], -1, 2))
+    xk_ = torch.view_as_complex(xk.float().reshape(*xk.shape[:-1], -1, 2))
+    freqs_cis = reshape_for_broadcast(freqs_cis, xq_)
+    xq_out = torch.view_as_real(xq_ * freqs_cis).flatten(3)
+    xk_out = torch.view_as_real(xk_ * freqs_cis).flatten(3)
+    return xq_out.type_as(xq), xk_out.type_as(xk)
+
+def precompute_freqs_cis(
+    dim: int, end: int, theta: float = 10000.0, use_scaled: bool = False
+):
+    freqs = 1.0 / (theta ** (torch.arange(0, dim, 2)[: (dim // 2)].float() / dim))
+    t = torch.arange(end, device=freqs.device, dtype=torch.float32)
+    if use_scaled:
+        freqs = apply_scaling(freqs)
+    freqs = torch.outer(t, freqs)
+    freqs_cis = torch.polar(torch.ones_like(freqs), freqs)  # complex64
+    return freqs_cis

llmc_py/tokenizer.py

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+# From: https://github.com/meta-llama/llama-models/blob/main/models/llama3_1/api/tokenizer.py
+
+import os
+from pathlib import Path
+from typing import (
+    AbstractSet,
+    Callable,
+    Collection,
+    Dict,
+    Iterator,
+    List,
+    Literal,
+    Optional,
+    Sequence,
+    Union,
+    cast,
+)
+
+import tiktoken
+from tiktoken.load import load_tiktoken_bpe
+
+# The tiktoken tokenizer can handle <=400k chars without
+# pyo3_runtime.PanicException.
+TIKTOKEN_MAX_ENCODE_CHARS = 400_000
+
+# https://github.com/openai/tiktoken/issues/195
+# Here we iterate over subsequences and split if we exceed the limit
+# of max consecutive non-whitespace or whitespace characters.
+MAX_NO_WHITESPACES_CHARS = 25_000
+
+
+class Tokenizer:
+    """
+    Tokenizing and encoding/decoding text using the Tiktoken tokenizer.
+    """
+
+    special_tokens: Dict[str, int]
+
+    num_reserved_special_tokens = 256
+
+    pat_str = r"(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+"  # noqa: E501
+
+    def __init__(self, model_path: str):
+        """
+        Initializes the Tokenizer with a Tiktoken model.
+
+        Args:
+            model_path (str): The path to the Tiktoken model file.
+        """
+        assert os.path.isfile(model_path), model_path
+
+        mergeable_ranks = load_tiktoken_bpe(model_path)
+        num_base_tokens = len(mergeable_ranks)
+        special_tokens = [
+            "<|begin_of_text|>",
+            "<|end_of_text|>",
+            "<|reserved_special_token_0|>",
+            "<|reserved_special_token_1|>",
+            "<|finetune_right_pad_id|>",
+            "<|step_id|>",
+            "<|start_header_id|>",
+            "<|end_header_id|>",
+            "<|eom_id|>",  # end of message
+            "<|eot_id|>",  # end of turn
+            "<|python_tag|>",
+        ]
+        reserved_tokens = [
+            f"<|reserved_special_token_{2 + i}|>"
+            for i in range(self.num_reserved_special_tokens - len(special_tokens))
+        ]
+        special_tokens = special_tokens + reserved_tokens
+
+        self.special_tokens = {
+            token: num_base_tokens + i for i, token in enumerate(special_tokens)
+        }
+        self.model = tiktoken.Encoding(
+            name=Path(model_path).name,
+            pat_str=self.pat_str,
+            mergeable_ranks=mergeable_ranks,
+            special_tokens=self.special_tokens,
+        )
+
+        self.n_words: int = num_base_tokens + len(special_tokens)
+        # BOS / EOS token IDs
+        self.bos_id: int = self.special_tokens["<|begin_of_text|>"]
+        self.eos_id: int = self.special_tokens["<|end_of_text|>"]
+        self.eot_id: int = self.special_tokens["<|eot_id|>"]
+        self.eom_id: int = self.special_tokens["<|eom_id|>"]
+        self.python_tag_id = self.special_tokens["<|python_tag|>"]
+        self.pad_id: int = self.special_tokens["<|finetune_right_pad_id|>"]
+        self.stop_tokens = [
+            self.special_tokens["<|eom_id|>"],
+            self.special_tokens["<|eot_id|>"],
+        ]
+
+    def encode(
+        self,
+        s: str,
+        *,
+        bos: bool,
+        eos: bool,
+        allowed_special: Optional[Union[Literal["all"], AbstractSet[str]]] = None,
+        disallowed_special: Union[Literal["all"], Collection[str]] = (),
+    ) -> List[int]:
+        """
+        Encodes a string into a list of token IDs.
+
+        Args:
+            s (str): The input string to be encoded.
+            bos (bool): Whether to prepend the beginning-of-sequence token.
+            eos (bool): Whether to append the end-of-sequence token.
+            allowed_tokens ("all"|set[str]): allowed special tokens in string
+            disallowed_tokens ("all"|set[str]): special tokens that raise an error when in string
+
+        Returns:
+            list[int]: A list of token IDs.
+
+        By default, setting disallowed_special=() encodes a string by ignoring
+        special tokens. Specifically:
+        - Setting `disallowed_special` to () will cause all text corresponding
+          to special tokens to be encoded as natural text (insteading of raising
+          an error).
+        - Setting `allowed_special` to "all" will treat all text corresponding
+          to special tokens to be encoded as special tokens.
+        """
+        if allowed_special is None:
+            allowed_special = set()
+        assert type(s) is str
+
+        substrs = (
+            substr
+            for i in range(0, len(s), TIKTOKEN_MAX_ENCODE_CHARS)
+            for substr in self._split_whitespaces_or_nonwhitespaces(
+                s[i : i + TIKTOKEN_MAX_ENCODE_CHARS], MAX_NO_WHITESPACES_CHARS
+            )
+        )
+        t: List[int] = []
+        for substr in substrs:
+            t.extend(
+                self.model.encode(
+                    substr,
+                    allowed_special=allowed_special,
+                    disallowed_special=disallowed_special,
+                )
+            )
+        if bos:
+            t.insert(0, self.bos_id)
+        if eos:
+            t.append(self.eos_id)
+        return t
+
+    def decode(self, t: Sequence[int]) -> str:
+        """
+        Decodes a list of token IDs into a string.
+
+        Args:
+            t (List[int]): The list of token IDs to be decoded.
+
+        Returns:
+            str: The decoded string.
+        """
+        # Typecast is safe here. Tiktoken doesn't do anything list-related with the sequence.
+        return self.model.decode(cast(List[int], t))
+
+    @staticmethod
+    def _split_whitespaces_or_nonwhitespaces(
+        s: str, max_consecutive_slice_len: int
+    ) -> Iterator[str]:
+        """
+        Splits the string `s` so that each substring contains no more than `max_consecutive_slice_len`
+        consecutive whitespaces or consecutive non-whitespaces.
+        """
+        current_slice_len = 0
+        current_slice_is_space = s[0].isspace() if len(s) > 0 else False
+        slice_start = 0
+
+        for i in range(len(s)):
+            is_now_space = s[i].isspace()
+
+            if current_slice_is_space ^ is_now_space:
+                current_slice_len = 1
+                current_slice_is_space = is_now_space
+            else:
+                current_slice_len += 1
+                if current_slice_len > max_consecutive_slice_len:
+                    yield s[slice_start:i]
+                    slice_start = i
+                    current_slice_len = 1
+        yield s[slice_start:]

llmc_py/utils.py

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+# Taken from:
+# 1) https://github.com/meta-llama/llama-models/blob/main/models/llama3_1/api/model.py
+# 2) https://github.com/meta-llama/llama3/blob/11817d47e1ba7a4959b025eb1ca308572e0e3963/llama/generation.py
+
+import torch
+from torch import nn
+
+# Special modules
+class RMSNorm(torch.nn.Module):
+    def __init__(self, dim: int, eps: float = 1e-6):
+        super().__init__()
+        self.eps = eps
+        self.weight = nn.Parameter(torch.ones(dim))
+
+    def _norm(self, x):
+        return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps)
+
+    def forward(self, x):
+        output = self._norm(x.float()).type_as(x)
+        return output * self.weight
+
+# Sampling
+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
+
+# GQA
+def repeat_kv(x: torch.Tensor, n_rep: int) -> torch.Tensor:
+    """torch.repeat_interleave(x, dim=2, repeats=n_rep)"""
+    bs, slen, n_kv_heads, head_dim = x.shape
+    if n_rep == 1:
+        return x
+    return (
+        x[:, :, :, None, :]
+        .expand(bs, slen, n_kv_heads, n_rep, head_dim)
+        .reshape(bs, slen, n_kv_heads * n_rep, head_dim)
+    )