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.