Mark Lohry <[email protected]> writes: > -snes_converged_reason: > > Nonlinear solve did not converge due to DIVERGED_LOCAL_MIN iterations 4 > > (which is expected)
If you set -snes_stol $something_large then SNES will exit SNES_CONVERGED_SNORM_RELATIVE instead of SNES_DIVERGED_LINE_SEARCH when it stagnates. >> Add -snes_converged_reason. What do you want to do when the solver >> fails? Pretend like it succeeded and get the wrong answer? Usually >> people shorten the time step and retry, which is what you see happening >> here. > Well yes, actually - I expected it to fail for this test case but it > stubbornly gets the right answer. Sorry about that. ;-) > The explicit integrator has no problem keeping a fixed timestep and > throwing the expected NaNs when it blows up. > > It's alarming to see the unexpected behavior of setting TSADAPTNONE and > seeing it actually adapting (in a rudimentary fashion) the timestep, and > keeping that reduced timestep even after the stiffness goes away. We figured it's not very useful to just crash or get the wrong answer, so the solver-based control is decoupled from error-based control.
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