Garrett Bingham

Garrett Bingham

About Me


I am a Ph.D. candidate in the Neural Networks Research Group at The University of Texas at Austin. My research focuses on smart automated machine learning. I developed AutoInit, an algorithm that creates customized weight initialization strategies for different neural networks. I also introduced PANGAEA, a method that leverages evolutionary optimization and gradient descent to discover novel parametric activation functions that outperform ReLU and other baseline functions.

 

Research


AutoInit: Analytic Signal-Preserving Weight Initialization for Neural Networks

Garrett Bingham and Risto Miikkulainen
Under Review

AutoInit Neural Network Weight Initialization

Neural networks require careful weight initialization to prevent signals from exploding or vanishing. Existing initialization schemes solve this problem in specific cases by assuming that the network has a certain activation function or topology. It is difficult to derive such weight initialization strategies, and modern architectures therefore often use these same initialization schemes even though their assumptions do not hold. This paper introduces AutoInit, a weight initialization algorithm that automatically adapts to different neural network architectures. By analytically tracking the mean and variance of signals as they propagate through the network, AutoInit is able to appropriately scale the weights at each layer to avoid exploding or vanishing signals. Experiments demonstrate that AutoInit improves performance of various convolutional and residual networks across a range of activation function, dropout, weight decay, learning rate, and normalizer settings. Further, in neural architecture search and activation function meta-learning, AutoInit automatically calculates specialized weight initialization strategies for thousands of unique architectures and hundreds of unique activation functions, and improves performance in vision, language, tabular, multi-task, and transfer learning scenarios. AutoInit thus serves as an automatic configuration tool that makes design of new neural network architectures more robust. The AutoInit package provides a wrapper around existing TensorFlow models and is available at https://github.com/cognizant-ai-labs/autoinit.

 

Discovering Parametric Activation Functions

Garrett Bingham and Risto Miikkulainen
Under Review

Parametric Activation Functions

Recent studies have shown that the choice of activation function can significantly affect the performance of deep learning networks. However, the benefits of novel activation functions have been inconsistent and task dependent, and therefore the rectified linear unit (ReLU) is still the most commonly used. This paper proposes a technique for customizing activation functions automatically, resulting in reliable improvements in performance. Evolutionary search is used to discover the general form of the function, and gradient descent to optimize its parameters for different parts of the network and over the learning process. Experiments with four different neural network architectures on the CIFAR-10 and CIFAR-100 image classification datasets show that this approach is effective. It discovers both general activation functions and specialized functions for different architectures, consistently improving accuracy over ReLU and other recently proposed activation functions by significant margins. The approach can therefore be used as an automated optimization step in applying deep learning to new tasks.

 

Evolutionary Optimization of Deep Learning Activation Functions

Garrett Bingham*, William Macke*, and Risto Miikkulainen
GECCO 2020

Evolved Activation Functions

The choice of activation function can have a large effect on the performance of a neural network. While there have been some attempts to hand-engineer novel activation functions, the Rectified Linear Unit (ReLU) remains the most commonly-used in practice. This paper shows that evolutionary algorithms can discover novel activation functions that outperform ReLU. A tree-based search space of candidate activation functions is defined and explored with mutation, crossover, and exhaustive search. Experiments on training wide residual networks on the CIFAR-10 and CIFAR-100 image datasets show that this approach is effective. Replacing ReLU with evolved activation functions results in statistically significant increases in network accuracy. Optimal performance is achieved when evolution is allowed to customize activation functions to a particular task; however, these novel activation functions are shown to generalize, achieving high performance across tasks. Evolutionary optimization of activation functions is therefore a promising new dimension of metalearning in neural networks.

 

Improving Low-Resource Cross-lingual Document Retrieval by Reranking with Deep Bilingual Representations

Rui Zhang, Caitlin Westerfield, Sungrok Shim, Garrett Bingham, Alexander Fabbri, William Hu, Neha Verma, Dragomir Radev
ACL 2019

ACL

Low-resource cross-lingual document retrieval performance is improved with deep bilingual query-document representations. Experimental results on the MATERIAL dataset show that our model outperforms the competitive translation-based baselines on English-Swahili, English-Tagalog, and English-Somali cross-lingual information retrieval tasks.

 

Part of Speech Tagging with Neural Architecture Search

Garrett Bingham

DARTS Neural Architecture Search

An automatically discovered bidirectional recurrent architecture nearly matches state-of-the-art accuracy for part of speech tagging across 60 treebanks.
Image credit: https://github.com/quark0/darts

 

Ineffectiveness of Gradient-based Neural Architecture Search

Garrett Bingham

Ineffectiveness of Gradient-based Neural Architecture Search

Most neural architecture search approaches utilize reinforcement learning or neuroevolutionary methods. Architecture optimization by gradient descent has been considered as a possible alternative. However, by training language models on Penn treebank, we demonstrate that gradient descent explores the search space ineffectively, and find that randomly initialized architectures are often able to outperform those discovered after extensive searching. We argue that gradient descent simply serves as a proxy for arbitrarily modifying the architecture, and show that gradient descent does not discover more capable architectures with each iteration of architecture search.

 

Preliminary Studies on a Large Face Database

Benjamin Yip, Garrett Bingham, Katherine Kempfert, Jonathan Fabish, Troy Kling, Cuixian Chen, and Yishi Wang
2018 IEEE International Conference on Big Data

MORPH-II

I discovered thousands of gender, race, and birthdate inconsistencies in the MORPH-II face image dataset that previously published research had missed. In this paper we discuss our strategy to fix these errors and release these corrections in the hope that future research utilizing MORPH-II will be more accurate.

 

Random Subspace Two-dimensional LDA for Face Recognition

Garrett Bingham

RS-2DLDA

Random Subspace Two-dimensional LDA (RS-2DLDA) improves upon a 2D generalization of LDA in which the input data is left in matrix form instead of being vectorized. RS-2DLDA builds an ensemble of classifiers by performing k-nearest neighbor classification in subspaces defined by random selections of the feature vectors learned during training. This gives high accuracy and prevents overfitting. Applied to face recognition, RS-2DLDA outperformed similar approaches on the MORPH-II and ORL datasets.

 

News


Cognizant

I joined the Evolutionary AI research team at Cognizant.

TXCS Researchers Design Evolutionary Algorithms for Neural Networks

Our research was featured in the UT Austin Computer Science Department newsletter.

UT Austin

I began my Ph.D. studies at The University of Texas at Austin.

Amazon

In Amazon's Robotics AI group I developed an automated and parallelized solution for a video classification workflow.

Yale University

I graduated cum laude from Yale University with a B.S. in Computer Science & Mathematics.

LILY Lab

In the Language, Information, and Learning at Yale (LILY) Lab, I worked on cross-lingual information retrieval for the IARPA MATERIAL Program under the supervision of Prof. Dragomir Radev.

Reservoir Labs

At Reservoir Labs, I used a polyhedral compiler to speed up neural network computations by improving a tool called R-Stream.TF. I was supervised by Dr. Benoit Meister.

AIT-Budapest

I studied computer science at the Aquincum Institute of Technology in Budapest, Hungary.

University of North Carolina Wilmington

Supervised by Dr. Cuixian Chen and Dr. Yishi Wang at UNC Wilmington, I developed a new algorithm for face recognition called RS-2DLDA. I presented a poster of my work at the Council on Undergraduate Research REU Symposium at The Westin Alexandria and delivered an oral presentation at the NES Mathematical Association of America Meeting hosted by Sacred Heart University.

Hobbies


In my free time I enjoy trail running, biking, and rock climbing. Check out my latest adventures on Strava!