[petsc-users] SNES realted

[Matthew Knepley]

On Thu, Jan 16, 2014 at 6:28 PM, Dharmendar Reddy
<dharmareddy84 at gmail.com>wrote:

> Hello,
>         I am solving a set of equations with SNES
> F1 (x1,x2,x3) = 0
> F2 (x1,x2,x3) = 0
> F3 (x1,x2,x3) = 0
>
> x1 and x2 are always > 0, how do i enforce that during the linesearch ?
>

There are two options:

  a) Make your own line search that projects the step

      This is what we have traditionally done. It can destroy convergence,
but its simple.

  b) Use SNESVI and set bounds on x1 and x2

      This is supposed to work, but has hardly been tested at all. When we
get some time
      we plan on beating on this. If you feel like being a guinea pig, do
this.

    Matt


> The system of equations is shown on page 1 of pdf here
> http://dunham.ee.washington.edu/ee531/notes/SemiRev.pdf
>
> F1 = equation 1
> F2 = equation 2
> F3 = equation 5
>
> x1 = n, X2=p and X3 = psi
>
> Thanks
> Reddy
>



-- 
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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