Add Backward Euler solver (rebased) #2239
Conversation
Convert the SNES solver (which never converged for real problems) into a backward Euler solver. Both `beuler` and `snes` solver type names can be used for now. Nearly twice as fast as CVODE for same atol/rtol settings (10 mins vs 19) on quite complex 1D Hermes simulation with neon (https://github.com/bendudson/hermes-3/tree/master/examples/1D-neon)
Explicit comparisons against zero error code
Out of domain errors should be handled by calling PETSc function, rather than returning an error code.
* next: Remove the Karniadakis time solver clang-tidy suggetion Manual entry on provenance-tracking metadata Save provenance tracking info from grid file
|
Fiddling about this to try and get it to pass constexpr int beuler_nout = 1e5;
root["beuler"]["nout"] = beuler_nout;
root["beuler"]["output_step"] = end / beuler_nout;Making the initial timestep very small, or tightening the tolerances makes very little difference. |
This is really a steady-state solver, and not suitable for oscillatory solutions like the one in this test
![github-actions[bot]](https://avatars.githubusercontent.com/in/15368?s=60&v=4){kind=small}
| @@ -47,39 +47,55 @@ class SNESSolver; | |||
|
|
|||
| namespace { | |||
| RegisterSolver<SNESSolver> registersolversnes("snes"); | |||
| } | |||
| RegisterSolver<SNESSolver> registersolverbeuler("beuler"); | |||
There was a problem hiding this comment.
warning: variable registersolverbeuler defined in a header file; variable definitions in header files can lead to ODR violations [misc-definitions-in-headers]
RegisterSolver<SNESSolver> registersolverbeuler("beuler");
^| public: | ||
| SNESSolver(Options *opt = nullptr) : Solver(opt) {} | ||
| public: | ||
| SNESSolver(Options* opt = nullptr) : Solver(opt) {} |
There was a problem hiding this comment.
warning: constructor does not initialize these fields: timestep, dt, lower_its, upper_its, out_timestep, nsteps, diagnose, nlocal, neq, snes_f, snes_x, x0, predictor, x1, snes, Jmf [cppcoreguidelines-pro-type-member-init]
SNESSolver(Options* opt = nullptr) : Solver(opt) {}
^
| // "solver" section, as we run into problems when solvers use the same | ||
| // name for an option with inconsistent defaults | ||
| auto options = Options::getRoot()->getSection("beuler"); | ||
| auto solver = std::unique_ptr<Solver>{Solver::create("beuler", options)}; |
There was a problem hiding this comment.
warning: auto options can be declared as auto *options [readability-qualified-auto]
auto options = Options::getRoot()->getSection("beuler");
^~~~~
auto *
Evolves to steady state, compares against known solution.
Co-authored-by: Peter Hill <zed.three@gmail.com>
Replaces #2238, based on an updated
nextbranch to avoid conflicts.