TY  - JOUR
AU  - Schöbel, Ruth
AU  - Speck, Robert
TI  - PFASST-ER: combining the parallel full approximation scheme in space and time with parallelization across the method
JO  - Computing and visualization in science
VL  - 23
IS  - 1-4
SN  - 1432-9360
CY  - Heidelberg
PB  - Springer
M1  - FZJ-2020-03974
SP  - 12
PY  - 2020
AB  - To extend prevailing scaling limits when solving time-dependent partial differential equations, the parallel full approximation scheme in space and time (PFASST) has been shown to be a promising parallel-in-time integrator. Similar to space–time multigrid, PFASST is able to compute multiple time-steps simultaneously and is therefore in particular suitable for large-scale applications on high performance computing systems. In this work we couple PFASST with a parallel spectral deferred correction (SDC) method, forming an unprecedented doubly time-parallel integrator. While PFASST provides global, large-scale “parallelization across the step”, the inner parallel SDC method allows integrating each individual time-step “parallel across the method” using a diagonalized local Quasi-Newton solver. This new method, which we call “PFASST with Enhanced concuRrency” (PFASST-ER), therefore exposes even more temporal concurrency. For two challenging nonlinear reaction-diffusion problems, we show that PFASST-ER works more efficiently than the classical variants of PFASST and can use more processors than time-steps.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000572641700001
DO  - DOI:10.1007/s00791-020-00330-5
UR  - https://juser.fz-juelich.de/record/885633
ER  -