[petsc-users] Meaning of error message (gamg & fieldsplit related)

[Safin, Artur]

Barry, Mark,

Apologies for taking a while to respond.

Are you saying it works for a while but fails when the problem is large, or that it never works with fieldsplit_1? And how many processors are you using?

All of these are serial runs. The preconditioner always fails for large problems; but I also found an example where it fails for a fairly small matrix. fieldsplit_1 is the one that fails, although fieldpslit_0 always works.

This should be fixed in the master branch

I tried the developmental version (from today), but the same bug persists.



I have some code that reproduces the example. The index sets that I use are non-overlapping; I also checked with matlab that each fieldsplit submatrix is non-singular.
The issue is with fieldsplit_TA: if I do not use -fieldsplit_TA-pc_type_gamg, then the solver converges. Otherwise, it crashes with the same message.

Artur


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