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GALINI: An extensible mixed-integer quadratically-constrained optimization solver.
Abstract not provided.
thornado-transport: Anderson- and GPU-accelerated nonlinear solvers for neutrino-matter coupling
Algorithms for neutrino-matter coupling in core-collapse supernovae (CCSNe) are investigated in the context of a spectral two-moment model, which is discretized in space with the discontinuous Galerkin method, integrated in time with implicit-explicit (IMEX) methods, and implemented in the toolkit for high-order neutrino-radiation hydrodynamics (thornado). The model considers electron neutrinos and antineutrinos and tabulated opacities from Bruenn (1985), which includes neutrino-electron scattering and pair processes. The nonlinear system arising from implicit time discretization of the equations governing neutrino-matter coupling is iterated to convergence using Anderson-accelerated fixed-point methods, which avoid formation of Jacobians and inversion of dense linear systems. Numerical experiments show that, for a given tolerance, a nested iteration scheme which aims to reduce opacity evaluations can lower the computational cost. Our initial port to GPUs, using both OpenMP and OpenACC, shows an overall speedup of up to ~ 100× when compared to results using a single CPU core. These results indicate that the algorithms implemented in thornado are well-suited to GPU acceleration.
Linear and Nonlinear Solvers for Simulating High-Temperature Multiphase Flow Within Large-Scale Engineered Subsurface Systems.
Abstract not provided.
ADELUS: A Performance-Portable Dense LU Solver for Distributed-Memory Hardware-Accelerated Systems.
Abstract not provided.
IMPLEMENTATION OF THE ENERGY EQUATION SOLVER TO THE LATTICE BOLTZMANN METHOD-BASED CODE PRATHAM
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Improving numerical solvers for enabling extended-term simulations to better understand the impact of rapidly increasing renewable generation on the grid.
Abstract not provided.
Incorporating Multiple Compute Precisions into the GMRES Linear Solver.
Abstract not provided.
Space-time solvers for incompressible flow
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Neural Network Solver for Coherent Synchrotron Radiation Wakefield Calculations in Accelerator-Based Charged Particle Beams
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Linear & Nonlinear Solvers for Simulating High-Temperature Multiphase Flow Within Large-scale Engineered Subsurface Systems.
Abstract not provided.
Accelerated Deployment of MFEM Based Solvers in Large Scale Industrial Problems
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A Neural PDE Solver with Temporal Stencil Modeling
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Parallel Training of GRU Networks with a Multi-Grid Solver for Long Sequences.
Abstract not provided.
Development and benchmarking of transient nodal code SIMULATE5-K neutron kinetics solver
SIMULATE5-K is Studsvik's next generation best estimate transient code. The time dependent diffusion equation is solved with a nodal method consistent with that implemented in the licensed core design code SIMULATE5. Arbitrary number of neutron and delayed neutron precursor groups can be used. For the solution of the spatial problem, the coupling coefficients used to relate the node leakages are found by first converting the time dependent diffusion equation to a static diffusion equation with the use of flux and delayed neutron precursor dynamic frequencies. Once the static-like equations are obtained, the multi-group analytical nodal model is used to obtain the coupling coefficients, expressing the node leakage in terms of adjacent node average fluxes. The coupling coefficients are then inserted into the time dependent nodal balance equation. For the time integration, the time dependent neutron balance equation is solved with the frequency transformation method. The treatment of the temporal dependence yields a fixed source problem which can be solved utilizing the existing fixed-source methodology. The primary purpose of this paper is to describe the neutron kinetics methodology implemented in SIMULATE5-K. The accuracy of the method is demonstrated for a series of well-known, neutronic-only benchmark problems. (author)