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David Vargas receives Student Paper Award for the second time!

Graduate student David Vargas just won the 2023 Copper Mountain Conference Student Paper Competition. David is a student of Jacob Schroder, and this is the second time David wins this award (2022), a rare feat. 

Congratulations David, you make us really proud!!

Title of winning paper: A general framework for deriving coarse grid operators for Multigrid Reduction in Time

ABSTRACT. In order to utilize modern exascale computers, Multigrid Reduction in Time (MGRIT) introduces parallelism to the time dimension by solving the initial value problem using multigrid. Although it is well known that the convergence of MGRIT depends on the choice of coarse-grid time-stepping operator, the derivation, in general, of a "good" coarse-grid operator remains an open problem. To address this, we introduce a general framework, called the $\theta$ method, for deriving accurate coarse operators in the family of Runge-Kutta methods. We motivate the problem by examining MGRIT convergence in the naive case, where the coarse-grid is a simple re-discretization of the fine-grid. We then derive order conditions for the coarse operator to match the fine-grid to a given accuracy. We derive several methods to demonstrate the technique, and demonstrate enhanced theoretical MGRIT convergence. Finally, we confirm the convergence bounds numerically on the linear advection-diffusion equation.