[FLASH-USERS] FLASH4-beta released

Thu Feb 2 13:58:33 EST 2012

Dear James,

There are two things that have been done for the gravity coupling to hydro
routines. Note that this is only for the unsplit hydry/MHD solvers, and
nothing to do with the split PPM solver.

One of them is a bug fix and the other is an improvement:

(1) Half time (n+1/2) gravitational potential update (coupling) with hydro
(bug fix):

In the routine hy_uhd_addGravityUnsplit.F90, we had a wrong implementation
in adding the three gravitational potential accelerations (x, y, and z
directions) to hydro as source terms. This fix only affects when using
Poisson solver to calculate gravitational potential:

  use_gravHalfUpdate = .true.
  use_gravPotUpdate = .true.
  use_gravConsv = .false.

This will NOT affect if not using the potential update

  use_gravHalfUpdate = .true.
  use_gravPotUpdate = .false.
  use_gravConsv = .false. (or .true.)

Note that use_gravPotUpdate = .true. only works with use_gravConsv = .false.

(2) n+1 update of gravity as a source term (improvement):
What we had before was to add gravity components to momenta first and then
energy. However, after carefully testing a set of numerical problems and
comparing the unsplit solver's results with those of the split PPM solver,
we found that the ordering should be changed. We now have energy update
first followed by momenta update.

Hope this helps for you. Thank you for your interest in this FLASH4-beta
release.

Best,
Dongwook
=========================================
Dongwook Lee, Ph.D., Research Scientist
FLASH Center for Computational Science
University of Chicago
5747 S. Ellis Ave., Room 319
(773) 834-6830

> Hi Klaus, I was unable to find any additional information in the user
> guide
> on this point in the release notes:
>
> The use of Gravitational acceleration is handled more accurately in
>> Hydrodynamics.
>
>
> Could you clarify as to what the improvements are?
>
> Thanks!
> - James
>
> On Wed, Feb 1, 2012 at 11:33 AM, Klaus Weide
> <klaus at flash.uchicago.edu>wrote:
>
>>
>> The Flash Center is pleased to announce the beta release of the next
>> version of the FLASH code, version 4 beta. FLASH 4 beta includes
>> several new capabilities and resolves many bugs found in
>> previous releases up to 4-alpha.
>>
>>
>> The capabilities added since the alpha release are :
>>
>> Capabilities added since the FLASH4-alpha include:
>>
>> * 3T capabilities, support for non-Cartesian geometry, and support for
>> stationary rigid bodies in the unsplit hydrodynamics solver
>>
>> * Upwind biased constrained transport (CT) scheme in the unsplit
>> staggered
>> mesh MHD solver
>>
>> * Full corner transport upwind (CTU) algorithm in the unsplit hydro/MHD
>> solver
>>
>> * Multi-Temperature Multi-Material Multi-Table Eos
>>
>> * Ability to use cold opacities
>>
>> * Several solvers have been threaded with two different degrees of
>> parallelism. The
>>  block level threading  is coarser grained with one FLASH block being
>> given to one
>>  thread, there is a finer grain threading which threads performance
>> critical loops.
>>  Both modes use OpenMP.
>>
>> * Laser drive is reconfigured and threaded.
>>
>> * Several new HEDP simulation setups have been added.
>>
>>
>> Improvements to capabilities since the alpha release include:
>>
>> * The HEDP capabilities have been more extensively tested, and are
>> therefore more robust.
>>
>> * Eos related runtime parameters are clearer.
>>
>> * Several new shortcuts have been added to make it easier to use the
>>  new HEDP capabilities.
>>
>> * The use of Gravitational acceleration is handled more accurately in
>> Hydrodynamics.
>>
>> * The interface with Hypre is more robust for diffusion.
>>
>> * More boundary conditions in PFFT, some Poisson solvers can now handle
>>  combinations of different boundary conditions (DIRICHLET, NEUMANN,
>> PERIODIC)
>>  on different domian boundaries.
>>
>>
>> Known Limitations:
>>
>> * The new multipole solver is missing the ability to treat
>>  a non-zero minimal radius for spherical geometries, and the
>>  ability to specify a point mass contribution to the potential.
>>
>> * Unsplit diffusion does not work in 3D.
>>
>> * HYPRE needs to be installed to use Unsplit Diffusion, Unsplit
>> diffusion
>>  uses hypre-2.7.0b (might not be backward compatible).
>>
>> * Usage of HYPRE Split solver in FLASH4 is only for internal debugging
>> purposes
>>  and is not generally recommended for usage.
>>
>> * Split diffusion has not been tested with PARAMESH.
>>
>> * Some configurations of hydrodynamic test problems with Chombo grid
>>  show worse than expected mass and total energy conservation.  Please
>>  see the Chombo section in Hydro chapter of the FLASH user guide for
>>  details.
>>
>> * We have experienced the following abort when running
>>  IsentropicVortex problem with Chombo Grid:
>>  "MayDay: TreeIntVectSet.cpp:1995: Assertion `bxNumPts != 0' failed.
>> !!!"
>>  We are currently in contact with the Chombo team to resolve this
>>  issue.
>>
>> * The absoft compiler produces erroneous results with optimization in
>>  gr_markRefineDerefine routine. The results are fine without
>>  optimization. There may be other files with similar behavior, but
>>  this is the only one we are aware of.
>>
>> * The PG compiler fails to compile source files which contain OpenMP
>>  parallel regions that reference threadprivate data.  This happens in
>>  the threaded versions of the Multipole solver and the within block
>>  threaded version of split hydro.  A workaround is to remove
>>  "default(none)" from the OpenMP parallel region.
>>
>> * The unsplit hydro solver has an issue with preserving symmetry in
>>  non-fixed block size mode in UG.
>>
>> * The ReineckeMeyer setup will not compile with the NAG compiler because
>>  of the presence of f77 like file used computing analytical solution
>>
>> * We have been unable to use Hyper with OpenMPI in the FLASH code, the
>>  runs result in execution failures.
>>
>> * The -index-reorder setup flag does not work in all the configurations.
>>  If you wish to use it please contact the FLASH team.
>>
>> * A longer list of changes is contained in the User's Guide in Section
>> 1,
>>  What's New in This Release.
>>
>> The release is available at:
>>
>> http://flash.uchicago.edu/site/flashcode/
>>
>> A stripped down version of FLASH3 that may be downloaded without a
>> license is also available at the same site.  This is essentially the
>> FLASH framework without any implementations. Additionally a collection
>> of mini-apps that represent the FLASH workload in many different
>> configurations is also availble under the general FLASH license
>> agreement.
>>
>>
>> The Flash Center continues to provide support for "add-ons" to the
>> code.
>>
>> Additionally, the FLASH testing software FlashTest, which became
>> available with the FLASH3, continues to be available for
>> download at:
>>
>> http://flash.uchicago.edu/site/flashcode/
>>
>> The code architecture and most interfaces of FLASH4 are compatible
>> with FLASH3.  Many, but not all parts are also backward compatible
>> with FLASH2.  The Flash Center has written extensive documentation
>> detailing how to make the transition from FLASH2 to FLASH3 as smooth
>> as possible.  The user should look to:
>>
>> http://flash.uchicago.edu/site/flashcode/user_support/
>>
>> The website also contains other documentation including a User's Guide
>> and a developer's section.  A new feature from FLASH3 onward is the
>> online description of the public interface routines to various code
>> units. A new feature from the current release is a list of available
>> setup shortcuts.
>>
>>
>> Development of the FLASH Code was funded by the DOE-supported
>> ASC/Alliance Center for Astrophysical Thermonuclear Flashes,
>> and continues to be funded by DOE NNSA and NSF.  We
>> acknowledge support received from Lawrence Livermore National
>> Laboratory and the University of Chicago.
>>
>> All publications resulting from the use of the FLASH Code must
>> acknowledge the Flash Center for Computational Science.
>>  Addition of the following text to the paper acknowledgments
>> will be sufficient.
>>
>>        "The software used in this work was in part developed by the
>>        DOE-supported Flash Center for Computational Science
>>        at the University of Chicago."
>>
>
>
>
> --
> James Guillochon
> Department of Astronomy & Astrophysics
> University of California, Santa Cruz
> jfg at ucolick.org
>