[petsc-users] conditioning of snes with dmcomposite & grid sequencing

[Matthew Knepley]

On Fri, Sep 11, 2015 at 9:08 AM, Gideon Simpson <gideon.simpson at gmail.com>
wrote:

> Following up on the previous thread, for my dm composite problem, I find
> that at the end of the first grid sequence,where it fails to converge, the
> distribution of the norms between the two pieces are:
>
>  39 SNES Function norm 2.253098577796e+02
>  40 SNES Function norm 2.253098577331e+02
>  41 SNES Function norm 2.253098577228e+02
>  42 SNES Function norm 2.253098577212e+02
>  43 SNES Function norm 2.253098577174e+02
>  44 SNES Function norm 2.253098577166e+02
>  45 SNES Function norm 2.253098577158e+02
>  46 SNES Function norm 2.253098577157e+02
>  47 SNES Function norm 2.253098577156e+02
>  48 SNES Function norm 2.253098577156e+02
> Nonlinear solve did not converge due to DIVERGED_LINE_SEARCH iterations 48
>  ||r|| = 225.31, 7999 entries
>  ||rp|| = 140.021, 3 entries
>  ||rQ|| = 176.518, 7996 entries
>
> Since I think we were convinced that this was intrinsic to the problem,
> and not a function of the Jacobian function, I am using my Jacobian.
>

Okay, I see no pattern in the fields. Lets plot these 2 vectors, -vec_view
draw, and screenshot.

  Matt


> -gideon
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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