Joshua Day, PhD

My name is Josh. I'm a generalist that's worked with a ton of different domains. If my specialty is anything its translating whiteboard math into fast, usable software. Julia is my language of choice, and every project I build is driven by two priorities: performance and usability.

About Me

• I'm the Director of Software Engineering at Rallypoint One, a veteran-owned small business focused on open-source scientific computing, AI/ML, and digital twins for government R&D.

  

• I do a lot of open source development.

• I am the creator and main contributor to the Julia for Data Science newsletter.

• I have a PhD in Statistics from NC State. My research into on-line algorithms for statistics led to the development of the OnlineStats Julia package.

Current Focus

I'm currently building Julia tooling for geospatial and environmental computing at RallypointOne, including:

• HEATMAPS (NSF ASCEND-funded): GPU-accelerated digital twin framework for wildfire propagation modeling using surrogates and physics-informed neural networks.
• MICROCAST (Navy SBIR-funded): Hybrid forecasting framework for naval operations integrating SpeedyWeather, Oceananigans, Breeze, and ML weather prediction.

Things I've Built

Statistics & Data

• OnlineStats.jl: Single-pass algorithms for statistics and data viz with big data.

Web & Markup

• XML.jl: An XML reader/writer in pure Julia that performs comparably to implementations in C.
• Cobweb.jl: An HTML reader/writer in pure Julia that's fast and easy to use.
• PlotlyLight.jl: Lightweight, easy-to-use wrapper of the fantastic Plotly.js plotting library.

Geospatial & Simulation

• Wildfires.jl: Wildfire modeling and simulation in Julia.
• Elmfire.jl: Julia implementation of the ELMFIRE fire propagation model.
• GlobalGrids.jl: Discrete global grids in Julia.
• GeoSurrogates.jl: Surrogate function representations of geospatial data.
• RapidRefreshData.jl: Downloads data from NOAA RAP/HRRR/GFS weather models.
• DeckGL.jl: WebGL-powered geospatial visualizations in Julia via deck.gl.
• Landfire.jl: Julia client for the LANDFIRE Product Service API.
• GeoExplorer.jl: Interactive geospatial exploration in Julia.

Tools & Utilities

• TokenIterators.jl: Fast framework for writing lexers/tokenizers.
• DepotDelivery.jl: Create a standalone Julia depot for air-gapped deployments.
• XKCD.jl: Retrieve image and metadata from the XKCD webcomic.

Apps

• One Click Tuner: iOS app with a chromatic musical instrument tuner.

And much more... GitHub repos