Time parallel RIDC and SDC #634
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connorjward
reviewed
May 15, 2025
tommbendall
previously approved these changes
Aug 20, 2025
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tommbendall
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I haven't checked line-by-line if the implementation matches the maths, but have worked through the tests and comments and am happy that this looks thorough!
I think we're planning on waiting to merge but I'm happy to approve it
Co-authored-by: Thomas Bendall <thomas.bendall@metoffice.gov.uk>
jshipton
reviewed
Dec 19, 2025
| pass to the underlying nonlinear solver. Defaults to None. | ||
| limiter (:class:`Limiter` object, optional): a limiter to apply to | ||
| the evolving field to enforce monotonicity. Defaults to None. | ||
| options (:class:`AdvectionOptions`, optional): an object containing |
| limiter (:class:`Limiter` object, optional): a limiter to apply to | ||
| the evolving field to enforce monotonicity. Defaults to None. | ||
| options (:class:`AdvectionOptions`, optional): an object containing | ||
| reduced (bool, optional): whether to use reduced or full stencils for RIDC. |
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| reduced (bool, optional): whether to use reduced or full stencils for RIDC. | |
| reduced (bool, optional): whether to use reduced stencils for RIDC. Defaults to True. |
| pass to the underlying nonlinear solver. Defaults to None. | ||
| limiter (:class:`Limiter` object, optional): a limiter to apply to | ||
| the evolving field to enforce monotonicity. Defaults to None. | ||
| options (:class:`AdvectionOptions`, optional): an object containing |
| self.comm.send(self.source_Uk[m+1], dest=self.kval+1, tag=self.TAG_EXCHANGE_SOURCE + self.step) | ||
| else: | ||
| for m in range(1, self.kval + 1): | ||
| # Recieve and evaluate the stencil of guesses we need to correct |
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| # Recieve and evaluate the stencil of guesses we need to correct | |
| # Receive and evaluate the stencil of guesses we need to correct |
| self.comm.send(self.source_Ukp1[m+1], dest=self.kval+1, tag=self.TAG_EXCHANGE_SOURCE + self.step) | ||
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| for m in range(self.kval, self.M): | ||
| # Recieve the guess we need to correct and evaluate the rhs |
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| # Recieve the guess we need to correct and evaluate the rhs | |
| # Receive the guess we need to correct and evaluate the rhs |
| BE, LU, TRAP, EXACT, PIC, OPT, WEIRD, MIN-SR-NS, MIN-SR-S | ||
| qdelta_exp (str): Explicit Qdelta matrix to be used. Options are | ||
| FE, EXACT, PIC | ||
| formulation (str, optional): Whether to use node-to-node or zero-to-node |
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I can't see this option in the interface!
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Time parallel SDC and RIDC implementations. Splits SDC code into
deferred_correctionandparallel_dc. All should inherit from one overall DC class (Parallel_RIDC from RIDC and Parallel_SDC from SDC).Parallel SDC uses the diagonal preconditioners to compute solutions separately on each node, meaning we have M + 1 communicators.
Parallel RIDC pipelines the corrections, by having the number of nodes (M+1) being much greater than the number of corrections. It uses equispaced nodes on coarse intervals. Each correction (and the initial low order solution) are computed in parallel, meaning we have K + 1 communicators.
Serial RIDC has the reduced stencil and full stencil implementations, only the reduced stencil is used for Parallel RIDC.
The Firedrake Ensemble communicator is used for time parallelisation.