Hi, I'm Alex 👋

I'm a PhD student in the University of Wisconsin-Madison statistics program. My github is a mixture of research code, #rstats ✨ contributions, and personal data analysis projects. I write long-form explainers on my blog, https://www.alexpghayes.com/. At the moment most of my energy goes to research.

Research & research code

I study community detection in networks with Karl Rohe, primarily using spectral methods. My research code is all in R at the moment, and none of it is on CRAN, primarily because my research packages are only about 75 percent done; the key functionality works but documentation, tests, and other user-friendly elements may be missing.

• aPPR helps you calculate approximate personalized pageranks from large graphs, including those that can only be queried via an API. aPPR additionally performs degree correction and regularization, allowing users to recover blocks from stochastic blockmodels. Leverages socialsampler and twittercache to cache targeted network samples as the personalized pagerank calculations run. Read the paper.

• vsp performs semi-parametric estimation of latent factors in random-dot product graphs by computing varimax rotations of the spectral embeddings of graphs. The resulting factors are sparse and interpretable. Read the paper.

• fastRG samples random-dot product graphs much faster than naive sampling procedures and is especially useful when running simulation studies. See the paper for a description of the fastRG core algorithm.

• fastadi performs self-tuning matrix completion via adaptive thresholding, often outperforming softImpute. See the paper for algorithmic and theoretical details. I have also extended this algorithm to work with matrices where the entire upper triangle is observed as part of some work on citation networks.

#rstats

I am involved in a number of open source projects in the tidyverse and tidymodels orbits. In particular, I maintain the broom package, which currently has ~6 million downloads, and for my contributions am an author on the tidyverse paper. I intermittently participate in the Stan and ROpenSci communities as well.

Please get in touch if...

• you'd like to hire me for a research or data science for social good internship,
• you want to discuss design of statistical modeling software,
• you want to collaborate on a research project, or
• you want to write an explainer together.

Outside of R, I'm a proficient Python user, and can pull together enough SQL, C++, Julia, and PySpark to get things done.

I am responsive on Twitter at @alexpghayes and via email.