NAME
Gravity_potentialListOfBlocks
SYNOPSIS
call Gravity_potentialListOfBlocks(integer(IN) :: blockCount,
integer(IN) :: blockList(blockCount),
optional,integer(IN) :: potentialIndex)
DESCRIPTION
This routine computes the gravitational potential on all
blocks specified in the list, for the gravity implementations
(i.e., various Poisson implementations), which make use of it
in computing the gravitational acceleration.
The resulting potential can be considered as zone-averaged.
Supported boundary conditions are isolated (0) and
periodic (1). The same boundary conditions are applied
in all directions. For some implementation of Gravity,
in particular with Barnes-Hut tee solver, additional combinations
of boundary conditions may be supported.
ARGUMENTS
blockCount : The number of blocks in the list
blockList(:) : The list of blocks on which to calculate potential
potentialIndex : If present, determines which variable in UNK to use
for storing the updated potential. If not present,
GPOT_VAR is assumed.
Presence or absense of this optional dummy argument
also determines whether some side effects are enabled
or disabled; see discussion of two modes under NOTES
below.
NOTES
Gravity_potentialListOfBlocks can operate in one of two modes:
* automatic mode - when called without the optional potentialIndex.
Such a call will usually be made once per time step, usually
from the main time advancement loop in Driver_evolveFlash.
Various side effects are enabled in this mode, see SIDE EFFECT below.
* explicit mode - when called with the optional potentialIndex.
The potential is stored in the variable explicitly given, and
side effects like saving the previous potential in GPOL_VAR
and updating some sink particle state and properties are
suppressed.
This call does nothing for those Gravity implementations provided with
FLASH that just provide a given (time-independent) potential for other
physics modules and don't compute the potential by invoking a solver:
Constant, PointMass, and PlanePar.
SIDE EFFECTS
Updates certain variables in permanent UNK storage to contain the
gravitational potential. Invokes a solver (of the Poisson equation)
if necessary. On return, if potentialIndex is not present,
GPOT_VAR: contains potential for the current simulation time.
GPOL_VAR (if defined): contains potential at the previous simulation time.
On return, if potentialIndex is present, the UNK variable given by
potentialIndex contains the newly computed potential.
May affect other variables related to particle properties if particles
are included in the simulation. In particular,
PDEN_VAR (if defined): may get updated to the current density from
particles if particles have mass.
There are additional side effects if sink particles are used.
These effects happen by calls to Particles_sinkAccelGasOnSinks and
Particles_sinkAccelSinksOnGas, which may update sink particle
properties and additional UNK variables that store
accelerations. The calls are only made in automatic mode.
May modify certain variables used for intermediate results by the solvers
invoked. The list of variables depends on the Gravity implementation.
The following information is subject to change without notice.
For the Multigrid implementation:
ISLS_VAR (residual)
ICOR_VAR (correction)
IMGM_VAR (image mass)
IMGP_VAR (image potential)
For the Multipole implementation:
(none)