SECOND FLAMR (FLuid AMR) WORKSHOP (FOCUS GROUP)

May 23-June 2nd, 2006, CITA U Toronto

CO-SPONSORS: NSERC, NSF, CITA, UBC, CIAR, PITP


Confirmed  participants


Arrival
Departure
Location
Contact #
Dale Choi
May 25
June 3


Matt Choptuik
May 21
May 30


Will Dinkel
May 24
May 26


Jonathan Dursi
local

1201A (416) 978-1776
Chris Matzner
local


(416) 978-2172
Hugh Merz
local

1218 (416) 978-8801
Scott Noble
May 31
June 4


Inaki Olabarietta
May 29
June 4


Luis Lehner
May 31
June 3


Jason Penner
May 23
June 2


Ue-Li Pen
local

1208
(416) 978-6477
Frans Pretorius
local

1106
(780) 952-4722
Martin Snajdr
May 23
May 31


Aaryn Tonita
May 23
May 26


Chris Thompson
local

1207A (416) 978-8784
Various other CITAzens
local




OVERVIEW AND GOALS OF THE WORKSHOP

Background

Over the past years many of the workshop participants and collaborators have invested a significant amount time developing numerical tools and techniques to solve the field equations of general relativity (GR). The predominant focus was on vacuum spacetimes, or spacetimes coupled to simple matter fields, in particular scalar fields. Among the primary tools developed in this regard were a set of software libraries, PAMR (Parallel Adaptive Mesh Refinement) amd AMRD (Adaptive Mesh Refinement Driver), designed to solve the kind coupled ellpitic/hyperbolic systems of PDEs typically encountered in GR, using finite difference techniques with AMR in a parallel computing environment. One of our more pressing research goals is to incorporate "realistic" matter fields, to simulate a wider variety of astrophysically interesting scenarios where strong-field gravity is expected to play an important role, such as binary neutron star or neutron star black hole mergers. In this regard, PAMR is somewhat lacking, in that it assumes vertex centered solution methods. The FLAMR I workshop was initiated last year to begin work to update the libaries to support cell centered solution methods. Since we want to retain our vertex centered techniques for GR, yet if desired use cell centered solution methods for matter fields, we are forced to investigate infrastructures that are able to manage both a vertex and cell representation of the same fundamental variable. This is because, as in general, all matter fields and the metric will be coupled to one another. A given variable will be evolved with either a cell or vertex centered scheme, and the library will (semi) transparently maintain the "conjugate" representation of the variable.

FLAMR II Workshop Goals:

Primary goal: update PAMR/AMRD to support a system of coupled elliptic/hyperbolic equations, where any equation can be solved using vertex or cell centered techniques. To test the new software in the most general computational setting, we will solve the following model problem: a boson star coupled to a "Newtonian" metric, ds2 = - (1 + 2V) dt2 + 1/(1 + 2V) hij dxi dxj, where V is the Newtonian potential sourced by the complex scalar field energy density and hij is a flat spatial metric. The real (imaginary) component of the scalar field will be treated with cell-centered (vertex-centered) methods, whereas the potential will be solved for via the Poisson equation using vertex centered multigrid. The reason for this particular model problem is that it tests all of the above described infrastructure with about a simple a set of coupled matter/gravity equations as one could imagine, but that still mimics the computational structure of the full problem.

Secondary goal: scope out a series of near term, interesting projects to pursue with the newly developed code. This will include discussions of the relevant physics/astrophysics that needs to be modelled, and selecting the "best" related numerical solution methods.

SCHEDULE (tentative ,and may be superceded by local events)

Tuesday, May 23

Time
Event/Title
Speaker
Location
10:00am-11:00am
pre-workshop discussion group

CITA lounge, 12th Floor
11:00am-1:00pm
work session

TBA
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

TBA

Wednesday, May 24

Time
Event/Title
Speaker
Location
10:00am-11:00am
Opening remarks, overview of goals & model problem
M. Choptuik
1318A
11:00am-12:00pm
Overview of PAMR/AMRD
F. Pretorius
1318A
12:00pm-1:00pm
Structure/status of unigrid code for model problem
M. Snajdr
1318A
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Thursday, May 25

Time
Event/Title
Speaker
Location
10:00am-1:00pm
work session

1218
11:10am-12:10pm
field trip to Astro Fluids Discussion group

1318A
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Friday, May 26


Time
Event/Title
Speaker
Location
10:00am-1:00pm
work session

1218
1:00pm-2:00pm
Lunch


2:00pm-4:00pm
work session

1218
4:00pm-4:30pm
CITA dessert social

12th floor lounge


Monday, May 29

Time
Event/Title
Speaker
Location
10:00am-11:00am
Quick overview of numerical methods for hydrodynamics on grids
J. Dursi
1318A
11:00am-12:00pm
TBA (On neutron star physics relating to the "secondary" goal of the workshop)
C. Thompson
1318A
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Tuesday, May 30

Time
Event/Title
Speaker
Location
10:00am-1:00pm
work session

1218
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Wednesday, May 31

Time
Event/Title
Speaker
Location
10:00am-1:00pm
work session

1218
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Thursday, June 1

Time
Event/Title
Speaker
Location
10:00am-11:00am
Different issues of General Relativistic MHD problems
L. Lehner
1318A
11:00am-1:00pm
Work Session
1218
1:00pm-2:00pm
Lunch


2:00pm-6:00pm
work session

1218

Friday June 2


Time
Event/Title
Speaker
Location
10:00am-11:00am
The Kurganov-Tadmor schemed applied to numerical relativity
I. Olabarietta
1318A
11:00am-12:00pm
Simulating and Imaging Accretion Disks (e.g. Sgr A*) S. Noble 1318A
12:00pm-12:45pm Relativistic potentials - context and feedback
C. Matzner
1318A
1:00pm-2:00pm
Lunch


2:00pm-4:00pm
work session/debriefing

1218
4:00pm-4:30pm
CITA dessert social

12th floor lounge

Reference material (more to come later)

  1. NEW!! Video clip from UBC NR Relativity Meeting, May 17, 2006, further clarifying proposed model problem [200 MB MPEG]
  2. Video clip from UBC NR Relativity Meeting, April 20, 2006, clarifying proposed model problem [200 MB MPEG]
  3. Frans Pretorius, Numerical Relativity Using a Generalized Harmonic Decomposition, Class. Quant. Grav. 22 (2005) 425-452
  4. Pretorius: PAMR distribution [pamr.tar.gz | Browse distribution]
  5. PAMR documentation
    1. Pretorius: Adaptive Mesh Refinement Driver Reference Manual (PS)
    2. Pretorius: PAMR Reference Manual (PS)
    3. Choptuik: Compiling and running wave example on vnfe4 (HTML)
  6. Snajdr: 3D Relativistic / Self-gravitating Hydro Code with Ideal Gas (Synge) Equation of State [Browse Code]

RELATED (LEVERAGED) ACTIVITIES


BUDGET (EXPENDITURES)


BUDGET (EXPENDITURES)

Maintained by choptuik@physics.ubc.ca. Supported by CIAR, NSERC, CFI, BCKDF and UBC.