John Gouwar

PhD. Student in Northeastern University's Programming Research Laboratory

Photo of John Gouwar

About Me

I am a 3rd year PhD. student in the Programming Research Laboratory at Northeastern University advised by Arjun Guha. My current research is in applied programming languages, specifically with a focus on large language models for code generation. I also work on building scalable abstractions for probabilistic programs with Steven Holtzen. I am broadly interested in applying programming languages techniques (especially those related to building compilers and DSLs) across the landscape of computing to make programs faster, safer, and more expressive.

Before coming to Northeastern, I am incredibly lucky to have attended Grinnell College where I received a BA in Computer Science and Mathematics. While at Grinnell, I worked with Professor Jerod Weinman on automated alignment of historical map images to modern GIS data. I also participated in the Rutgers-DIMACS REU program, where I worked with Professor Eric Allender on proving circuit lower bounds for non-interactive statistical zero-knowledge proof protocols.


I am most easily reached by email: gouwar.j (at) northeastern (dot) edu


Knowledge Transfer from High-Resource to Low-Resource Programming Languages for Code LLMs Preprint 2023
Federico Cassano, John Gouwar, Francesca Lucchetti, Claire Schlesinger, Carolyn Jane Anderson, Michael Greenberg, Abhinav Jangda, and Arjun Guha
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Over the past few years, Large Language Models of Code (Code LLMs) have started to have a significant impact on programming practice. Code LLMs are also emerging as a building block for research in programming languages and software engineering. However, the quality of code produced by a Code LLM varies significantly by programming languages. Code LLMs produce impressive results on programming languages that are well represented in their training data (e.g., Java, Python, or JavaScript), but struggle with low-resource languages, like OCaml and Racket. These languages enjoy dedicated communities (programming languages research; finance) but are not as well represented in training data as more broadly popular languages.

This paper presents an effective approach for boosting the performance of Code LLMs on low-resource languages using semi-synthetic data. Our approach generates high-quality datasets for low-resource languages, which can then be used to fine-tune any pretrained Code LLM. Our approach, called MultiPL-T, translates training data from high-resource languages into training data for low-resource languages in the following way. 1) We use a Code LLM to synthesize tests for commented code from a high-resource language, filtering out faulty tests and code with low test coverage. 2) We use a Code LLM to translate code to a target low-resource language, and use tests to validate the translation. We apply this approach to generate tens of thousands of new, validated training items for Racket, OCaml, and Lua from Python. Moreover, we use an open dataset (The Stack) and model (StarCoderBase), which allow us to decontaminate benchmarks and train models on this data without violating the model license.

With MultiPL-T generated data, we present fine-tuned versions of StarCoderBase that achieve state-of-the-art performance for Racket, OCaml, and Lua on benchmark problems. For Lua, our fine-tuned model achieves the same performance as StarCoderBase as Python—a very high-resource language–on the MultiPL-E benchmarks. For Racket and OCaml, we double their performance on MultiPL-E, bringing their performance close to higher-resource languages such as Ruby and C#.

The MultiPL-T approach is easy to apply to new languages and can immediately be used on any of the 18+ languages that MultiPL-E supports. Moreover, as we show, it is significantly more efficient and effective than alternates such as training longer.

MultiPL-E: A Scalable and Polyglot Approach to Benchmarking Neural Code Generation IEEE Transactions on Software Engineering (TSE) 2023
Federico Cassano, John Gouwar, Daniel Nguyen, Sydney Nguyen, Luna Phipps-Costin, Donald Pinckney, Ming-Ho Yee, Yangtian Zi, Carolyn Jane Anderson, Molly Q Feldman, Arjun Guha, Michael Greenberg, and Abhinav Jangda
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Large language models have demonstrated the ability to generate both natural language and programming language text. Although contemporary code generation models are trained on corpora with several programming languages, they are tested using benchmarks that are typically monolingual. The most widely used code generation benchmarks only target Python, so there is little quantitative evidence of how code generation models perform on other programming languages. We propose MultiPL-E, a system for translating unit test-driven code generation benchmarks to new languages. We create the first massively multilingual code generation benchmark by using MultiPL-E to translate two popular Python code generation benchmarks to 18 additional programming languages. We use MultiPL-E to extend the HumanEval benchmark (Chen et al., 2021) and MBPP benchmark (Austin et al., 2021) to 18 languages that encompass a range of programming paradigms and popularity. Using these new parallel benchmarks, we evaluate the multi-language performance of three state-of-the-art code generation models: Codex (Chen et al., 2021), CodeGen (Nijkamp et al., 2022) and InCoder (Fried et al., 2022). We find that Codex matches or even exceeds its performance on Python for several other languages. The range of programming languages represented in MultiPL-E allow us to explore the impact of language frequency and language features on model performance. Finally, the MultiPL-E approach of compiling code generation benchmarks to new programming languages is both scalable and extensible, making it straightforward to evaluate new models, benchmarks, and languages.

Cryptographic Hardness under Projections for Time-Bounded Kolmogorov Complexity Theoretical Computer Science 2023
Eric Allender, John Gouwar, Shuichi Hirahara, and Caleb Robelle
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A version of time-bounded Kolmogorov complexity, denoted KT, has received attention in the past several years, due to its close connection to circuit complexity and to the Minimum Circuit Size Problem MCSP. Essentially all results about the complexity of MCSP hold also for MKTP (the problem of computing the complexity of a string). Both and are hard for SZK (Statistical Zero Knowledge) under BPP-Turing reductions; neither is known to be NP-complete.

Recently, some hardness results for MKTP were proved that are not (yet) known to hold for MCSP. In particular, is hard for DET (a subclass of P) under nonuniform reductions. In this paper, we improve this, to show that co-MKTP is hard for the (apparently larger) class NISZKL under not only NC0 many-one reductions but even under projections. Also co-MKTP is hard for NISZK under non-uniform polynomial many-one reductions. Here, NISZK is the class of problems with non-interactive zero-knowledge proofs, and NISZKL is the non-interactive version of the class SZKL that was studied by Dvir et al.

As an application, we provide several improved worst-case to average-case reductions to problems in NP, and we obtain a new lower bound on MKTP (which is currently not known to hold for MCSP).

Deformable Part Models for Automatically Georeferencing Historical Map Images SIGSPATIAL 2019
Nicholas R. Howe, Jerod Weinman, John Gouwar, and Aabid Shamji
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Libraries are digitizing their collections of maps from all eras, generating increasingly large online collections of historical cartographic resources. Aligning such maps to a modern geographic coordinate system greatly increases their utility. This work presents a method for such automatic georeferencing, matching raster image content to GIS vector coordinate data. Given an approximate initial alignment that has already been projected from a spherical geographic coordinate system to a Cartesian map coordinate system, a probabilistic shape-matching scheme determines an optimized match between the GIS contours and ink in the binarized map image. Using an evaluation set of 20 historical maps from states and regions of the U.S., the method reduces average alignment RMSE by 12%.