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Publication Date
25 September 2023

Polaris Hackathon Retrospective

Figure 1: A plot showing second-order convergence in an idealized Polaris test case comparing numerical and analytic solutions for an inertial gravity wave that was added to Polaris during the hackathon.

In May, Los Alamos National Laboratory hosted a hackathon on Polaris, a new software for both regression testing of E3SM ocean and sea-ice components and analyzing E3SM output from those components. This hackathon followed two previous E3SM hackathons focused on MPAS-Analysis and the MPAS Framework. The nine participants, all of whom were staff scientists, developed new test cases for the MPAS-Seaice and MPAS-Ocean components. The ocean test cases were all focused on tests that will also be used in verification of the new OMEGA ocean component, a GPU enabled successor to MPAS-Ocean which is in the early stages of development. Significant progress was made on one group of sea-ice tests and four groups of ocean tests.

A major focus of the hackathon was introducing new developers to Polaris, since it is expected to become a major tool for regression testing and analysis for MPAS-Ocean, MPAS-Seaice, MALI and OMEGA components of E3SM. This included 2-day, interactive walkthrough of an introductory tutorial in which participants reproduced each step in developing a new group of tests on their own.

Another focus was on working in teams to a greater degree than had been achieved in previous hackathons. While some groups chose a divide-and-conquer strategy, other teams took turns doing the work while other participants looked on, making suggestions and asking questions. Team members with more experience with Polaris or its predecessor Compass could typically help their teammates get up to speed.

As with the previous hackathons, the participants said that the hackathon was important for building team cohesion and a sense of comradery. Also, similar to previous hackathons, participants acknowledged that the in-person participants got a richer experience (including social coffee breaks) than the virtual participants but the flexibility of virtual participation allowed several people to participate who could not have attended in person. Participants felt that format of 9 half days was a good way to structure the time, and most felt like they were unlikely to be able to commit more time than that in one block. The organizers, Carolyn and Xylar, put in a significant amount of preparation time before the hackathon, building out the tutorial, scoping out test cases, building draft documentation for each, and developing framework for test development and visualization. Participants felt like this extra preparation helped them hit the ground running at the start of the hackathon.

We look forward to future hackathons and encourage other E3SM and ecosystem groups to organize some of their own!

Hackathon organizers: Carolyn Begeman and Xylar Asay-Davis

Hackathon participants: Alice Barthel, Carolyn Begeman, Darin Comeau, Erin Thomas, Kat Smith, LeAnn Conlon, Sara Calandrini, Steven Brus, and Xylar Asay-Davis



  • Xylar Asay-Davis and Carolyn BegemanLos Alamos National Laboratory
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