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import hashlib |
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import os |
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import urllib |
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import warnings |
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from typing import Any, Union, List |
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from pkg_resources import packaging |
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import torch |
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from PIL import Image |
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from torchvision.transforms import Compose, Resize, CenterCrop, ToTensor, Normalize |
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from tqdm import tqdm |
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from .model import build_model |
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from .simple_tokenizer import SimpleTokenizer as _Tokenizer |
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try: |
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from torchvision.transforms import InterpolationMode |
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BICUBIC = InterpolationMode.BICUBIC |
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except ImportError: |
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BICUBIC = Image.BICUBIC |
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if packaging.version.parse(torch.__version__) < packaging.version.parse("1.7.1"): |
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warnings.warn("PyTorch version 1.7.1 or higher is recommended") |
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__all__ = ["available_models", "load", "tokenize"] |
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_tokenizer = _Tokenizer() |
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_MODELS = { |
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"RN50": "https://openaipublic.azureedge.net/clip/models/afeb0e10f9e5a86da6080e35cf09123aca3b358a0c3e3b6c78a7b63bc04b6762/RN50.pt", |
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"RN101": "https://openaipublic.azureedge.net/clip/models/8fa8567bab74a42d41c5915025a8e4538c3bdbe8804a470a72f30b0d94fab599/RN101.pt", |
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"RN50x4": "https://openaipublic.azureedge.net/clip/models/7e526bd135e493cef0776de27d5f42653e6b4c8bf9e0f653bb11773263205fdd/RN50x4.pt", |
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"RN50x16": "https://openaipublic.azureedge.net/clip/models/52378b407f34354e150460fe41077663dd5b39c54cd0bfd2b27167a4a06ec9aa/RN50x16.pt", |
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"RN50x64": "https://openaipublic.azureedge.net/clip/models/be1cfb55d75a9666199fb2206c106743da0f6468c9d327f3e0d0a543a9919d9c/RN50x64.pt", |
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"ViT-B/32": "https://openaipublic.azureedge.net/clip/models/40d365715913c9da98579312b702a82c18be219cc2a73407c4526f58eba950af/ViT-B-32.pt", |
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"ViT-B/16": "https://openaipublic.azureedge.net/clip/models/5806e77cd80f8b59890b7e101eabd078d9fb84e6937f9e85e4ecb61988df416f/ViT-B-16.pt", |
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"ViT-L/14": "https://openaipublic.azureedge.net/clip/models/b8cca3fd41ae0c99ba7e8951adf17d267cdb84cd88be6f7c2e0eca1737a03836/ViT-L-14.pt", |
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"ViT-L/14@336px": "https://openaipublic.azureedge.net/clip/models/3035c92b350959924f9f00213499208652fc7ea050643e8b385c2dac08641f02/ViT-L-14-336px.pt", |
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} |
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def _download(url: str, root: str): |
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os.makedirs(root, exist_ok=True) |
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filename = os.path.basename(url) |
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expected_sha256 = url.split("/")[-2] |
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download_target = os.path.join(root, filename) |
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if os.path.exists(download_target) and not os.path.isfile(download_target): |
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raise RuntimeError(f"{download_target} exists and is not a regular file") |
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if os.path.isfile(download_target): |
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if hashlib.sha256(open(download_target, "rb").read()).hexdigest() == expected_sha256: |
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return download_target |
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else: |
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warnings.warn(f"{download_target} exists, but the SHA256 checksum does not match; re-downloading the file") |
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with urllib.request.urlopen(url) as source, open(download_target, "wb") as output: |
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with tqdm(total=int(source.info().get("Content-Length")), ncols=80, unit='iB', unit_scale=True, unit_divisor=1024) as loop: |
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while True: |
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buffer = source.read(8192) |
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if not buffer: |
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break |
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output.write(buffer) |
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loop.update(len(buffer)) |
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if hashlib.sha256(open(download_target, "rb").read()).hexdigest() != expected_sha256: |
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raise RuntimeError("Model has been downloaded but the SHA256 checksum does not not match") |
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return download_target |
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def _convert_image_to_rgb(image): |
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return image.convert("RGB") |
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def _transform(n_px): |
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return Compose([ |
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Resize(n_px, interpolation=BICUBIC), |
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CenterCrop(n_px), |
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_convert_image_to_rgb, |
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ToTensor(), |
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Normalize((0.48145466, 0.4578275, 0.40821073), (0.26862954, 0.26130258, 0.27577711)), |
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]) |
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def available_models() -> List[str]: |
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"""Returns the names of available CLIP models""" |
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return list(_MODELS.keys()) |
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def load(name: str, device: Union[str, torch.device] = "cuda" if torch.cuda.is_available() else "cpu", jit: bool = False, download_root: str = None): |
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"""Load a CLIP model |
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Parameters |
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---------- |
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name : str |
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A model name listed by `clip.available_models()`, or the path to a model checkpoint containing the state_dict |
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device : Union[str, torch.device] |
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The device to put the loaded model |
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jit : bool |
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Whether to load the optimized JIT model or more hackable non-JIT model (default). |
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download_root: str |
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path to download the model files; by default, it uses "~/.cache/clip" |
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Returns |
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------- |
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model : torch.nn.Module |
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The CLIP model |
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preprocess : Callable[[PIL.Image], torch.Tensor] |
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A torchvision transform that converts a PIL image into a tensor that the returned model can take as its input |
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""" |
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if name in _MODELS: |
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model_path = _download(_MODELS[name], download_root or os.path.expanduser("~/.cache/clip")) |
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elif os.path.isfile(name): |
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model_path = name |
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else: |
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raise RuntimeError(f"Model {name} not found; available models = {available_models()}") |
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with open(model_path, 'rb') as opened_file: |
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try: |
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model = torch.jit.load(opened_file, map_location=device if jit else "cpu").eval() |
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state_dict = None |
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except RuntimeError: |
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if jit: |
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warnings.warn(f"File {model_path} is not a JIT archive. Loading as a state dict instead") |
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jit = False |
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state_dict = torch.load(opened_file, map_location="cpu") |
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if not jit: |
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model = build_model(state_dict or model.state_dict()).to(device) |
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if str(device) == "cpu": |
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model.float() |
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return model, _transform(model.visual.input_resolution) |
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device_holder = torch.jit.trace(lambda: torch.ones([]).to(torch.device(device)), example_inputs=[]) |
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device_node = [n for n in device_holder.graph.findAllNodes("prim::Constant") if "Device" in repr(n)][-1] |
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def patch_device(module): |
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try: |
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graphs = [module.graph] if hasattr(module, "graph") else [] |
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except RuntimeError: |
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graphs = [] |
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if hasattr(module, "forward1"): |
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graphs.append(module.forward1.graph) |
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for graph in graphs: |
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for node in graph.findAllNodes("prim::Constant"): |
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if "value" in node.attributeNames() and str(node["value"]).startswith("cuda"): |
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node.copyAttributes(device_node) |
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model.apply(patch_device) |
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patch_device(model.encode_image) |
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patch_device(model.encode_text) |
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if str(device) == "cpu": |
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float_holder = torch.jit.trace(lambda: torch.ones([]).float(), example_inputs=[]) |
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float_input = list(float_holder.graph.findNode("aten::to").inputs())[1] |
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float_node = float_input.node() |
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def patch_float(module): |
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try: |
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graphs = [module.graph] if hasattr(module, "graph") else [] |
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except RuntimeError: |
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graphs = [] |
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if hasattr(module, "forward1"): |
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graphs.append(module.forward1.graph) |
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for graph in graphs: |
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for node in graph.findAllNodes("aten::to"): |
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inputs = list(node.inputs()) |
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for i in [1, 2]: |
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if inputs[i].node()["value"] == 5: |
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inputs[i].node().copyAttributes(float_node) |
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model.apply(patch_float) |
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patch_float(model.encode_image) |
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patch_float(model.encode_text) |
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model.float() |
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return model, _transform(model.input_resolution.item()) |
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def tokenize(texts: Union[str, List[str]], context_length: int = 77, truncate: bool = False) -> Union[torch.IntTensor, torch.LongTensor]: |
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""" |
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Returns the tokenized representation of given input string(s) |
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Parameters |
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---------- |
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texts : Union[str, List[str]] |
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An input string or a list of input strings to tokenize |
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context_length : int |
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The context length to use; all CLIP models use 77 as the context length |
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truncate: bool |
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Whether to truncate the text in case its encoding is longer than the context length |
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Returns |
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------- |
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A two-dimensional tensor containing the resulting tokens, shape = [number of input strings, context_length]. |
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We return LongTensor when torch version is <1.8.0, since older index_select requires indices to be long. |
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""" |
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if isinstance(texts, str): |
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texts = [texts] |
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sot_token = _tokenizer.encoder["<|startoftext|>"] |
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eot_token = _tokenizer.encoder["<|endoftext|>"] |
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all_tokens = [[sot_token] + _tokenizer.encode(text) + [eot_token] for text in texts] |
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if packaging.version.parse(torch.__version__) < packaging.version.parse("1.8.0"): |
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result = torch.zeros(len(all_tokens), context_length, dtype=torch.long) |
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else: |
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result = torch.zeros(len(all_tokens), context_length, dtype=torch.int) |
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for i, tokens in enumerate(all_tokens): |
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if len(tokens) > context_length: |
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if truncate: |
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tokens = tokens[:context_length] |
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tokens[-1] = eot_token |
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else: |
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raise RuntimeError(f"Input {texts[i]} is too long for context length {context_length}") |
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result[i, :len(tokens)] = torch.tensor(tokens) |
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return result |
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