Despite considerable advances in neural language modeling, it remains an open question what the best decoding strategy is for text generation from a language model (e.g. to generate a story). The counter-intuitive empirical observation is that even though the use of likelihood as training objective leads to high quality models for a broad range of language understanding tasks, maximization-based decoding methods such as beam search lead to degeneration -output text that is bland, incoherent, or gets stuck in repetitive loops.To address this we propose Nucleus Sampling, a simple but effective method to draw considerably higher quality text out of neural language models than previous decoding strategies. Our approach avoids text degeneration by truncating the unreliable tail of the probability distribution, sampling from the dynamic nucleus of tokens containing the vast majority of the probability mass. To properly examine current maximization-based and stochastic decoding methods, we compare generations from each of these methods to the distribution of human text along several axes such as likelihood, diversity, and repetition. Our results show that (1) maximization is an inappropriate decoding objective for openended text generation, (2) the probability distributions of the best current language models have an unreliable tail which needs to be truncated during generation and (3) Nucleus Sampling is currently the best available decoding strategy for generating long-form text that is both high-quality -as measured by human evaluation -and as diverse as human-written text.Context: In a shocking finding, scientist discovered a herd of unicorns living in a remote, previously unexplored valley, in the Andes Mountains. Even more surprising to the researchers was the fact that the unicorns spoke perfect English.

由于在开放式文本生成中取得了重大进展，衡量机器生成的文本是如何对人类语言的关键问题。我们介绍紫红色，一个开放式文本生成的比较措施，它直接将文本生成模型的学习分布与使用发散边界的分发进行了分布到人写的文本。淡紫色通过计算量化嵌入空间中的信息分流来缩放到现代文本生成模型。通过对三个开放式发电任务的广泛实证研究，我们发现紫红色标识了所生成文本的已知属性，天然存在模型大小，并与人类判断相关，而不是现有的分布评估度量的限制较少。

文本生成对于许多自然语言处理应用至关重要。然而，基于最大化的解码方法（例如，神经语言模型的光束搜索）通常会导致解析解决方案 - 生成的文本是不自然的，并且包含不良的重复。现有方法通过采样或修改训练目标引入随机性，以降低某些令牌的概率（例如，不可能训练）。但是，它们通常会导致缺乏连贯性的解决方案。在这项工作中，我们表明，模型变性的根本原因是令牌表示的各向异性分布。我们提出了一种对比解决方案：（i）SIMCTG，是校准模型表示空间的对比训练目标，以及（ii）一种解码方法 - 对比度搜索 - 以鼓励多样性，同时在生成的文本中保持连贯性。对两种语言的三个基准测试的广泛实验和分析表明，我们提出的方法显着优于人类和自动指标评估的当前最新文本生成方法。

神经文本生成模型可能遭受低多样性问题。已经提出了各种解码策略和基于培训的方法仅通过利用上下文特征来促进多样性，但很少他们考虑纳入句法结构线索。在这项工作中，我们建议使用语言注释，即演讲（POS），来指导文本生成。详细地，我们将POS引导SoftMax介绍以显式模拟两个后部概率：（i）下一页POS，（ii）来自目标POS的词汇的下一个令牌。进一步提出POS导游采样策略来解决POS的多样性来解决低多样性问题。广泛的实验和人类评估表明，与现有最先进的方法相比，我们的POS引导的Softmax和采样（POSG）可以在保持相当的质量的同时产生更多样化的文本。

Generative AI has matured to a point where large-scale models can generate text that seems indistinguishable from human-written text and remarkably photorealistic images. Automatically measuring how close the distribution of generated data is to the target real data distribution is a key step in diagnosing existing models and developing better models. We present MAUVE, a family of comparison measures between pairs of distributions such as those encountered in the generative modeling of text or images. These scores are statistical summaries of divergence frontiers capturing two types of errors in generative modeling. We explore four approaches to statistically estimate these scores: vector quantization, non-parametric estimation, classifier-based estimation, and parametric Gaussian approximations. We provide statistical bounds for the vector quantization approach. Empirically, we find that the proposed scores paired with a range of $f$-divergences and statistical estimation methods can quantify the gaps between the distributions of human-written text and those of modern neural language models by correlating with human judgments and identifying known properties of the generated texts. We conclude the paper by demonstrating its applications to other AI domains and discussing practical recommendations.

深度神经语言模型的最新进展与大规模数据集的能力相结合，加速了自然语言生成系统的发展，这些系统在多种任务和应用程序上下文中产生流利和连贯的文本（在各种成功程度上）。但是，为所需的用户控制这些模型的输出仍然是一个开放的挑战。这不仅对于自定义生成语言的内容和样式至关重要，而且对于他们在现实世界中的安全可靠部署至关重要。我们提出了一项关于受约束神经语言生成的新兴主题的广泛调查，在该主题中，我们通过区分条件和约束（后者是在输出文本上而不是输入的可检验条件），正式定义和分类自然语言生成问题，目前是可检验的）约束文本生成任务，并查看受限文本生成的现有方法和评估指标。我们的目的是强调这个新兴领域的最新进展和趋势，以告知最有希望的方向和局限性，以推动受约束神经语言生成研究的最新作品。

神经文本生成的主导范式是自回归语言模型的左右解码。然而，复杂的词汇约束下的受约束或可控发生的产生需要远见计划未来可行的未来路径。从A *搜索算法绘制灵感，我们提出了一种神经系统A * esque，一种解码算法包含未来成本的启发式估计。我们开发了高效的寻找高效，对大规模语言模型有效，使我们的方法成为诸如光束搜索和顶-K采样等共同技术的替代品。为了使受约束的产生，我们构建了神经系统解码（Lu等，2021），将其灵活性结合到与未来约束满足的* esque估计结合起来的逻辑限制。我们的方法在五代任务中优于竞争力的基线，并在表格到文本生成，受限机器翻译和关键字的生成中实现了新的最先进的性能。在需要复杂约束满足或少量拍摄或零拍摄设置的任务上，改进尤其显着。神经系统A * esque说明了用于改进和实现大规模语言模型的新功能的解码的力量。

当前的语言模型可以产生高质量的文本。他们只是复制他们之前看到的文本，或者他们学习了普遍的语言抽象吗？要取笑这些可能性，我们介绍了乌鸦，这是一套评估生成文本的新颖性，专注于顺序结构（n-gram）和句法结构。我们将这些分析应用于四种神经语言模型（LSTM，变压器，变换器-XL和GPT-2）。对于本地结构 - 例如，单个依赖性 - 模型生成的文本比来自每个模型的测试集的人类生成文本的基线显着不那么新颖。对于大规模结构 - 例如，总句结构 - 模型生成的文本与人生成的基线一样新颖甚至更新颖，但模型仍然有时复制，在某些情况下，在训练集中重复超过1000字超过1,000字的通道。我们还表现了广泛的手动分析，表明GPT-2的新文本通常在形态学和语法中形成良好，但具有合理的语义问题（例如，是自相矛盾）。

Large pretrained language models generate fluent text but are notoriously hard to controllably sample from. In this work, we study constrained sampling from such language models: generating text that satisfies user-defined constraints, while maintaining fluency and the model's performance in a downstream task. We propose MuCoLa -- a sampling procedure that combines the log-likelihood of the language model with arbitrary (differentiable) constraints in a single energy function, and then generates samples in a non-autoregressive manner. Specifically, it initializes the entire output sequence with noise and follows a Markov chain defined by Langevin Dynamics using the gradients of the energy function. We evaluate MuCoLa on text generation with soft and hard constraints as well as their combinations obtaining significant improvements over competitive baselines for toxicity avoidance, sentiment control, and keyword-guided generation.

Natural language processing tasks, such as question answering, machine translation, reading comprehension, and summarization, are typically approached with supervised learning on taskspecific datasets. We demonstrate that language models begin to learn these tasks without any explicit supervision when trained on a new dataset of millions of webpages called WebText. When conditioned on a document plus questions, the answers generated by the language model reach 55 F1 on the CoQA dataset -matching or exceeding the performance of 3 out of 4 baseline systems without using the 127,000+ training examples. The capacity of the language model is essential to the success of zero-shot task transfer and increasing it improves performance in a log-linear fashion across tasks. Our largest model, GPT-2, is a 1.5B parameter Transformer that achieves state of the art results on 7 out of 8 tested language modeling datasets in a zero-shot setting but still underfits WebText. Samples from the model reflect these improvements and contain coherent paragraphs of text. These findings suggest a promising path towards building language processing systems which learn to perform tasks from their naturally occurring demonstrations.

神经文本生成模型，如用于总结和翻译的那些模型产生高质量的输出，但是当我们真正想要的是一个不同的选项时，通常会集中在模式周围。我们介绍了一个搜索算法来构建编码大量生成选项的格子。首先，我们将解码重组为最佳搜索，该搜索探讨了与光束搜索不同的空间，并通过避免修剪路径来提高效率。其次，我们重新审视假设重组的想法：我们可以在搜索期间识别类似的生成候选者，并将它们合并为近似。在摘要和机器翻译中，我们表明我们的算法编码了数百到数千个不同的选项，这些选项保持语法和高质量成一个线性型格子。该算法为在大规模不同输出之上构建下游生成应用提供了基础。

Open-ended text generation with autoregressive language models (LMs) is one of the core tasks in natural language processing. However, maximization-based decoding methods (e.g., greedy/beam search) often lead to the degeneration problem, i.e., the generated text is unnatural and contains undesirable repetitions. Existing solutions to this problem either introduce randomness prone to incoherence or require a look-ahead mechanism that demands extra computational overhead. In this study, we formulate open-ended text generation from a new perspective, i.e., we view it as an exploration process within a directed graph. Thereby, we understand the phenomenon of degeneration as circular loops within the directed graph. Based on our formulation, we propose a novel decoding method -- \textit{momentum decoding} -- which encourages the LM to \textit{greedily} explore new nodes outside the current graph. Meanwhile, it also allows the LM to return to the existing nodes with a momentum downgraded by a pre-defined resistance function. We extensively test our approach on three benchmarks from different domains through automatic and human evaluations. The results show that momentum decoding performs comparably with the current state of the art while enjoying notably improved inference speed and computation FLOPs. Furthermore, we conduct a detailed analysis to reveal the merits and inner workings of our approach. Our codes and other related resources are publicly available at https://github.com/gmftbyGMFTBY/MomentumDecoding.

大型预训练的语言模型能够产生多种多样的文本。从提示开始，这些模型产生了一种可以不可预测的叙述。现有的可控文本生成方法，该方法指导用户指定方向的文本中的叙述，需要创建培训语料库和额外的耗时培训程序。本文提出并调查了Contocation2Text，这是一种用于俄罗斯自动可控文本生成的插件方法，不需要微调。该方法基于两个交互模型：自回归语言Rugpt-3模型和自动编码语言Ruroberta模型。该方法的想法是根据自动编码模型的输出分布将自回归模型的输出分布移动，以确保文本中叙事的连贯过渡向指南短语，其中可以包含单个单词或搭配。能够考虑到令牌的左和右下方的自动编码模型“告诉”“自动回归模型”在当前一代步骤中，该模型是令牌最不合逻辑的，从而增加或降低了相应令牌的概率。使用该方法生成新闻文章的实验显示了其对自动生成的流利文本的有效性，这些文本包含用户指定的短语之间的连贯过渡。

公开可用的大型预磨语删除媒介（LMS）生成具有显着质量的文本，但仅从左右依次顺序地。因此，它们不会立即适用于打破单向假设的生成任务，例如释放或文本缺陷，需要特定于特定的监督。在本文中，我们呈现反射解码，这是一种新型无监督算法，其允许直接向非顺序任务应用单向LMS。我们的2步方法不需要监督甚至并行对象，只有两个离心的预磨损LMS相反的方向：向前和向后。首先，在上下文化步骤中，我们使用LMS生成过去和未来环境的集合，该上下文共同捕获输入（例如，索引源句）。其次，在反射步骤中，我们在这些“上下文集合”中的条件，生成与它们兼容的输出。综合经验结果表明，反思解码优于涉及释义和绑架文本缺陷的强烈无监督的基线，显着缩小无监督和监督方法之间的差距。反射解码超越了各种度量的多个监督基线，包括人为评估。

In this work, we explore a useful but often neglected methodology for robustness analysis of text generation evaluation metrics: stress tests with synthetic data. Basically, we design and synthesize a wide range of potential errors and check whether they result in a commensurate drop in the metric scores. We examine a range of recently proposed evaluation metrics based on pretrained language models, for the tasks of open-ended generation, translation, and summarization. Our experiments reveal interesting insensitivities, biases, or even loopholes in existing metrics. For example, we find that BERTScore ignores truncation errors in summarization, and MAUVE (built on top of GPT-2) is insensitive to errors at the beginning of generations. Further, we investigate the reasons behind these blind spots and suggest practical workarounds for a more reliable evaluation of text generation.

It has become common to publish large (billion parameter) language models that have been trained on private datasets. This paper demonstrates that in such settings, an adversary can perform a training data extraction attack to recover individual training examples by querying the language model. We demonstrate our attack on GPT-2, a language model trained on scrapes of the public Internet, and are able to extract hundreds of verbatim text sequences from the model's training data. These extracted examples include (public) personally identifiable information (names, phone numbers, and email addresses), IRC conversations, code, and 128-bit UUIDs. Our attack is possible even though each of the above sequences are included in just one document in the training data.We comprehensively evaluate our extraction attack to understand the factors that contribute to its success. Worryingly, we find that larger models are more vulnerable than smaller models. We conclude by drawing lessons and discussing possible safeguards for training large language models.

Controllable Text Generation (CTG) is emerging area in the field of natural language generation (NLG). It is regarded as crucial for the development of advanced text generation technologies that are more natural and better meet the specific constraints in practical applications. In recent years, methods using large-scale pre-trained language models (PLMs), in particular the widely used transformer-based PLMs, have become a new paradigm of NLG, allowing generation of more diverse and fluent text. However, due to the lower level of interpretability of deep neural networks, the controllability of these methods need to be guaranteed. To this end, controllable text generation using transformer-based PLMs has become a rapidly growing yet challenging new research hotspot. A diverse range of approaches have emerged in the recent 3-4 years, targeting different CTG tasks which may require different types of controlled constraints. In this paper, we present a systematic critical review on the common tasks, main approaches and evaluation methods in this area. Finally, we discuss the challenges that the field is facing, and put forward various promising future directions. To the best of our knowledge, this is the first survey paper to summarize CTG techniques from the perspective of PLMs. We hope it can help researchers in related fields to quickly track the academic frontier, providing them with a landscape of the area and a roadmap for future research.

用于评估有条件自然语言生成的传统自动化指标使用单个生成的文本和最佳匹配的金标准地面真相文本之间的成对比较。当有多个基础真相可用时，分数将使用参考中的平均或最大操作进行汇总。尽管这种方法在地面真相数据中的多样性（即有条件文本的分布的分散）可以归因于噪声，例如自动语音识别中，但在地面上的多样性的情况下，它不允许进行强有力的评估。真理代表模型的信号。在这项工作中，我们认为现有的指标不适合诸如视觉描述或摘要之类的域，而地面真理在语义上是多样的，并且这些字幕中的多样性捕获了有关上下文的有用的其他信息。我们提出了一种新的范式，用于对条件语言生成模型的多键入评估以及一个新的指标家族，该指标家族使用每种少量样本集比较参考和模型生成的字幕集的分布。我们通过视觉描述中的案例研究证明了方法的实用性：我们在其中证明现有模型优化了单描述质量而不是多样性，并获得了对采样方法和温度影响如何描述质量和多样性的一些见解。

We present a novel approach to generating news headlines in Finnish for a given news story. We model this as a summarization task where a model is given a news article, and its task is to produce a concise headline describing the main topic of the article. Because there are no openly available GPT-2 models for Finnish, we will first build such a model using several corpora. The model is then fine-tuned for the headline generation task using a massive news corpus. The system is evaluated by 3 expert journalists working in a Finnish media house. The results showcase the usability of the presented approach as a headline suggestion tool to facilitate the news production process.

We present the first comprehensive study on automatic knowledge base construction for two prevalent commonsense knowledge graphs: ATOMIC (Sap et al., 2019) and Con-ceptNet (Speer et al., 2017). Contrary to many conventional KBs that store knowledge with canonical templates, commonsense KBs only store loosely structured open-text descriptions of knowledge. We posit that an important step toward automatic commonsense completion is the development of generative models of commonsense knowledge, and propose COMmonsEnse Transformers (COMET ) that learn to generate rich and diverse commonsense descriptions in natural language. Despite the challenges of commonsense modeling, our investigation reveals promising results when implicit knowledge from deep pre-trained language models is transferred to generate explicit knowledge in commonsense knowledge graphs. Empirical results demonstrate that COMET is able to generate novel knowledge that humans rate as high quality, with up to 77.5% (ATOMIC) and 91.7% (ConceptNet) precision at top 1, which approaches human performance for these resources. Our findings suggest that using generative commonsense models for automatic commonsense KB completion could soon be a plausible alternative to extractive methods.