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Kelvin Xu

Alumni

Publications

Beyond Human Data: Scaling Self-Training for Problem-Solving with Language Models
Avi Singh
John D Co-Reyes
Piyush Patil
Xavier Garcia
Peter J. Liu
James Harrison
Jaehoon Lee
Aaron T Parisi
Abhishek Kumar
A. Alemi
Alex Rizkowsky
Azade Nova
Ben Adlam
Bernd Bohnet
Hanie Sedghi
Gamaleldin Fathy Elsayed
Igor Mordatch … (voir 21 de plus)
Isabelle Simpson
Izzeddin Gur
Jasper Snoek
Jeffrey Pennington
Jiri Hron
Kathleen Kenealy
Kevin Swersky
Kshiteej Mahajan
Laura Culp
Lechao Xiao
Maxwell Bileschi
Noah Constant
Roman Novak
Rosanne Liu
Tris Brian Warkentin
Yundi Qian
Ethan Dyer
Behnam Neyshabur
Jascha Sohl-Dickstein
Yamini Bansal
Noah Fiedel
Fine-tuning language models~(LMs) on human-generated data remains a prevalent practice. However, the performance of such models is often lim… (voir plus)ited by the quantity and diversity of high-quality human data. In this paper, we explore whether we can go beyond human data on tasks where we have access to scalar feedback, for example, on math problems where one can verify correctness. To do so, we investigate a simple self-training method based on expectation-maximization, which we call ReST
On integrating a language model into neural machine translation
An Actor-Critic Algorithm for Sequence Prediction
We present an approach to training neural networks to generate sequences using actor-critic methods from reinforcement learning (RL). Curren… (voir plus)t log-likelihood training methods are limited by the discrepancy between their training and testing modes, as models must generate tokens conditioned on their previous guesses rather than the ground-truth tokens. We address this problem by introducing a \textit{critic} network that is trained to predict the value of an output token, given the policy of an \textit{actor} network. This results in a training procedure that is much closer to the test phase, and allows us to directly optimize for a task-specific score such as BLEU. Crucially, since we leverage these techniques in the supervised learning setting rather than the traditional RL setting, we condition the critic network on the ground-truth output. We show that our method leads to improved performance on both a synthetic task, and for German-English machine translation. Our analysis paves the way for such methods to be applied in natural language generation tasks, such as machine translation, caption generation, and dialogue modelling.
A Controller Recognizer Framework: How necessary is recognition for control?
Recently there has been growing interest in building active visual object recognizers, as opposed to the usual passive recognizers which cla… (voir plus)ssifies a given static image into a predefined set of object categories. In this paper we propose to generalize these recently proposed end-to-end active visual recognizers into a controller-recognizer framework. A model in the controller-recognizer framework consists of a controller, which interfaces with an external manipulator, and a recognizer which classifies the visual input adjusted by the manipulator. We describe two most recently proposed controller-recognizer models: recurrent attention model and spatial transformer network as representative examples of controller-recognizer models. Based on this description we observe that most existing end-to-end controller-recognizers tightly, or completely, couple a controller and recognizer. We ask a question whether this tight coupling is necessary, and try to answer this empirically by building a controller-recognizer model with a decoupled controller and recognizer. Our experiments revealed that it is not always necessary to tightly couple them and that by decoupling a controller and recognizer, there is a possibility of building a generic controller that is pretrained and works together with any subsequent recognizer.
Theano: A Python framework for fast computation of mathematical expressions
Rami Al-Rfou
Amjad Almahairi
Christof Angermueller
Frédéric Bastien
Justin Bayer
Anatoly Belikov
Alexander Belopolsky
Josh Bleecher Snyder
Pierre-Luc Carrier
Paul Christiano
Myriam Côté
Yann N. Dauphin
Julien Demouth
Sander Dieleman
Ziye Fan
Mathieu Germain
Matt Graham
Balázs Hidasi
Arjun Jain
Kai Jia
Mikhail Korobov
Vivek Kulkarni
Pascal Lamblin
Eric Larsen
Sean Lee
Simon Lefrancois
Jesse A. Livezey
Cory Lorenz
Jeremiah Lowin
Qianli Ma
Robert T. McGibbon
Mehdi Mirza
Alberto Orlandi
Christopher Pal
Colin Raffel
Daniel Renshaw
Matthew Rocklin
Adriana Romero
Markus Roth
Peter Sadowski
John Salvatier
Jan Schlüter
John Schulman
Gabriel Schwartz
Iulian Vlad Serban
Samira Shabanian
Sigurd Spieckermann
S. Ramana Subramanyam
Gijs van Tulder
Sebastian Urban
Dustin J. Webb
Matthew Willson
Lijun Xue
Theano is a Python library that allows to define, optimize, and evaluate mathematical expressions involving multi-dimensional arrays efficie… (voir plus)ntly. Since its introduction, it has been one of the most used CPU and GPU mathematical compilers - especially in the machine learning community - and has shown steady performance improvements. Theano is being actively and continuously developed since 2008, multiple frameworks have been built on top of it and it has been used to produce many state-of-the-art machine learning models. The present article is structured as follows. Section I provides an overview of the Theano software and its community. Section II presents the principal features of Theano and how to use them, and compares them with other similar projects. Section III focuses on recently-introduced functionalities and improvements. Section IV compares the performance of Theano against Torch7 and TensorFlow on several machine learning models. Section V discusses current limitations of Theano and potential ways of improving it.