4 papers
Shifted HSS solvers for the indefinite Helmholtz equation
Colin J Cotter, Kars Knook, Joshua Hope-Collins
We provide an iterative solution approach for the indefinite Helmholtz equation discretised using finite elements, based upon a Hermitian Skew-Hermitian Splitting (HSS) iteration a…
Fully implicit timestepping methods for the rotating shallow water equations
Werner Bauer, Colin J. Cotter
Fully implicit timestepping methods have several potential advantages for atmosphere/ocean simulation. First, being unconditionally stable, they degrade more gracefully as the Cour…
Data assimilation using a global Girsanov nudged particle filter
Maneesh Kumar Singh, Joshua Hope-Collins, Colin J. Cotter +1
We present a particle filtering algorithm for stochastic models on infinite dimensional state space, making use of Girsanov perturbations to nudge the ensemble of particles into re…
asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond
Joshua Hope-Collins, Abdalaziz Hamdan, Werner Bauer +2
Modern high performance computers are massively parallel; for many PDE applications spatial parallelism saturates long before the computer's capability is reached. Parallel-in-time…