数值验证是机器学习研究的核心,因为它允许评估新方法的实际影响,并确认理论和实践之间的一致性。然而,该领域的快速发展构成了一些挑战:研究人员面临着大量的方法来比较,有限的透明度和最佳实践的共识以及乏味的重新实施工作。结果,验证通常是非常部分的,这可能会导致错误的结论,从而减慢研究的进展。我们提出了Benchopt,这是一个协作框架,旨在在跨编程语言和硬件体系结构的机器学习中自动化,复制和发布优化基准。 Benchopt通过提供用于运行,共享和扩展实验的现成工具来简化社区的基准测试。为了展示其广泛的可用性,我们在三个标准学习任务上展示基准:$ \ ell_2 $ regulaine的逻辑回归,套索和RESNET18用于图像分类的培训。这些基准强调了关键的实际发现,这些发现对这些问题的最新问题更加细微,这表明在实际评估中,魔鬼在细节上。我们希望Benchopt能在社区中促进合作工作,从而改善研究结果的可重复性。
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找到模型的最佳超参数可以作为双重优化问题,通常使用零级技术解决。在这项工作中,当内部优化问题是凸但不平滑时,我们研究一阶方法。我们表明,近端梯度下降和近端坐标下降序列序列的前向模式分化,雅各比人会收敛到精确的雅各布式。使用隐式差异化,我们表明可以利用内部问题的非平滑度来加快计算。最后,当内部优化问题大约解决时,我们对高度降低的误差提供了限制。关于回归和分类问题的结果揭示了高参数优化的计算益处,尤其是在需要多个超参数时。
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Sky-image-based solar forecasting using deep learning has been recognized as a promising approach in reducing the uncertainty in solar power generation. However, one of the biggest challenges is the lack of massive and diversified sky image samples. In this study, we present a comprehensive survey of open-source ground-based sky image datasets for very short-term solar forecasting (i.e., forecasting horizon less than 30 minutes), as well as related research areas which can potentially help improve solar forecasting methods, including cloud segmentation, cloud classification and cloud motion prediction. We first identify 72 open-source sky image datasets that satisfy the needs of machine/deep learning. Then a database of information about various aspects of the identified datasets is constructed. To evaluate each surveyed datasets, we further develop a multi-criteria ranking system based on 8 dimensions of the datasets which could have important impacts on usage of the data. Finally, we provide insights on the usage of these datasets for different applications. We hope this paper can provide an overview for researchers who are looking for datasets for very short-term solar forecasting and related areas.
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Neural networks can be trained to solve regression problems by using gradient-based methods to minimize the square loss. However, practitioners often prefer to reformulate regression as a classification problem, observing that training on the cross entropy loss results in better performance. By focusing on two-layer ReLU networks, which can be fully characterized by measures over their feature space, we explore how the implicit bias induced by gradient-based optimization could partly explain the above phenomenon. We provide theoretical evidence that the regression formulation yields a measure whose support can differ greatly from that for classification, in the case of one-dimensional data. Our proposed optimal supports correspond directly to the features learned by the input layer of the network. The different nature of these supports sheds light on possible optimization difficulties the square loss could encounter during training, and we present empirical results illustrating this phenomenon.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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Solar forecasting from ground-based sky images using deep learning models has shown great promise in reducing the uncertainty in solar power generation. One of the biggest challenges for training deep learning models is the availability of labeled datasets. With more and more sky image datasets open sourced in recent years, the development of accurate and reliable solar forecasting methods has seen a huge growth in potential. In this study, we explore three different training strategies for deep-learning-based solar forecasting models by leveraging three heterogeneous datasets collected around the world with drastically different climate patterns. Specifically, we compare the performance of models trained individually based on local datasets (local models) and models trained jointly based on the fusion of multiple datasets from different locations (global models), and we further examine the knowledge transfer from pre-trained solar forecasting models to a new dataset of interest (transfer learning models). The results suggest that the local models work well when deployed locally, but significant errors are observed for the scale of the prediction when applied offsite. The global model can adapt well to individual locations, while the possible increase in training efforts need to be taken into account. Pre-training models on a large and diversified source dataset and transferring to a local target dataset generally achieves superior performance over the other two training strategies. Transfer learning brings the most benefits when there are limited local data. With 80% less training data, it can achieve 1% improvement over the local baseline model trained using the entire dataset. Therefore, we call on the efforts from the solar forecasting community to contribute to a global dataset containing a massive amount of imagery and displaying diversified samples with a range of sky conditions.
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计算优化问题解决方案解决方案的雅各布是机器学习中的一个核心问题,其应用程序在超参数优化,元学习,优化为层和数据集蒸馏中的应用程序,仅举几例。展开的分化是一种流行的启发式方法,它使用迭代求解器近似溶液,并通过计算路径区分它。这项工作提供了对梯度下降和Chebyshev方法的二次目标的这种方法的非反应收敛速率分析。我们表明,为了确保雅各布的融合,我们可以1)选择较大的学习率,导致快速渐近地收敛,但接受该算法可能具有任意长的燃烧阶段或2)选择较小的学习率直接但较慢的收敛性。我们将这种现象称为展开的诅咒。最后,我们讨论了相对于这种方法的开放问题,例如为最佳展开策略得出实用的更新规则,并与Sobolev正交多项式领域建立了新的联系。
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在从机器人控制到仿真的各种机器人应用中,碰撞检测似乎是规范操作,包括运动计划和估计。尽管该主题的开创性工作可以追溯到80年代,但直到最近,正确区分碰撞检测的问题才成为一个中心问题,尤其要归功于科学界围绕该主题所做的持续和各种努力物理。然而,到目前为止,很少有人提出过解决方案,并且只有对所涉及形状的性质的强烈假设。在这项工作中,我们引入了一种通用和高效的方法,以计算任何一对凸形的碰撞检测的导数,这是通过尤其利用随机平滑技术而显示的,这些技术特别适合于捕获非平滑问题的衍生物。这种方法是在HPP-FCL和Pinocchio生态系统中实现的,并在机器人文献的经典数据集和问题上进行了评估,显示了很少的微秒时间来计算许多真实的机器人应用程序直接利用的信息衍生物,包括许多真实的机器人应用程序,包括可不同的模拟。
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强化学习(RL)和轨迹优化(TO)具有强大的互补优势。一方面,RL方法能够直接从数据中学习全球控制策略,但通常需要大型样本量以正确地收敛于可行的策略。另一方面,对方法能够利用从模拟器提取的基于梯度的信息,以快速收敛到局部最佳控制轨迹,该轨迹仅在解决方案附近有效。在过去的十年中,几种方法旨在充分结合两类方法,以获得两全其美的最佳选择。从这一研究开始,我们提出了这些方法的一些改进,以更快地学习全球控制政策,尤其是通过通过Sobolev学习来利用敏感性信息,并增强了Lagrangian技术来实施与政策学习之间的共识。我们通过与文献中的现有方法进行比较,评估了这些改进对机器人技术各种经典任务的好处。
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最近的研究表明,犯罪网络具有复杂的组织结构,但是是否可以用来预测犯罪网络的静态和动态特性。在这里,通过结合图表学习和机器学习方法,我们表明,可以使用政治腐败,警察情报和洗钱网络的结构性特性来恢复缺失的犯罪伙伴关系,区分不同类型的犯罪和法律协会以及预测犯罪分子之间交换的总金额,所有这些都具有出色的准确性。我们还表明,我们的方法可以预期在腐败网络的动态增长过程中,其准确性很高。因此,与在犯罪现场发现的证据类似,我们得出结论,犯罪网络的结构模式具有有关非法活动的重要信息,这使机器学习方法可以预测缺失的信息,甚至预测未来的犯罪行为。
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