[FLASH-USERS] Helmhotlz EOS question

[Robert Fisher]

Hi Malia :

  When you say the initial EOS data, I presume you mean that you've
verified the t = 0 data to be good. Helmholtz is fairly robust on good
data, so I suspect if you inspected the data passed to Helmholtz during
this call, you will find it to be already corrupted.

  To add to Dean's comment, in my experience as well, when the code dies in
Helmholtz, it is usually the symptom and not the underlying disease. The
'bad' data which manifests itself in this way is usually symptomatic of a
more fundamental problem elsewhere in the code. For instance, you may be
encountering a numerical instability in the hydrodynamics, or the nuclear
burning, but because these modules do not trap NaNs or Infs, they will
happily propagate to Helmholtz, where an exception is thrown.   You will
need to root out the underlying cause, because the NaNs and Infs will
progressively corrupt the simulation.

  Are you using nuclear burning in this simulation?

  Best wishes,

  Bob

On Wed, May 3, 2017 at 5:02 PM, Jenks, Malia T. <mjenks at ou.edu> wrote:

> I am getting the following error from the helmholtz eos about negative
> pressure:
>
>  [eos_helm] Negative total pressure.
>    values: dens,temp:   2.321442471007820E-004
> 1549.01220000000
>
>    values: abar,zbar:                 Infinity
> NaN
>
>    coulomb coupling parameter Gamma:
> NaN
>
>   Prad   1.45198E-02 Pion  0.00000E+00 Pele           NaN Pcoul
> 0.00000E+00
>
>   Ptot            NaN df_d    8.31451E+21
>
>
>
> I know that the initial mass fraction supplied to the eos is correct. The
> initial call of the eos sets abar and zbar correctly. I am not sure what is
> causing them to error. I also don't know why I am getting a NaN for the
> electron Pressure. Could anyone help point me to what is going wrong and
> how I can solve it?
>
> Thanks,
>
> Malia Jenks
>
>


-- 
Dr. Robert Fisher
Associate Professor / Graduate Program Director
University of Massachusetts/Dartmouth
Department of Physics
285 Old Westport Road
North Dartmouth, Massachusetts 02747
robert.fisher at umassd.edu
http://www.novastella.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20170504/d3d3b560/attachment.htm>