iField Discussion Notes, ITAPS Bootcamp, August 24, 2010

What sorts of things are definitely missing (reasonably expect applications
will want to do)
There are things that aren't in the current spec. that need to be
Things that aren't in the current spec. in there that we need to discuss
Things that aren't in the current spec. that we have no intention of putting there

What about implementation issues?
Biggest concern is interface impact on performance of implementation.


What about an analytic function over model entity?
Could this be handled by a specialized 'domain' constructor
all the complexty with how to get to 'mesh entities' hidden by 'iterator'

iField controls access to the 'domain'. Its not a separate iMesh thingy.

Why not name # components of tensor 'dimension'?

Need to add symmetry notions to tensor template definitions.
	What about constraints? Compressibility, divergence free, conserved,
	intensive/extensive.

Alternatives to defining slew of dfunc callbacks...
Could define a iDfunc interface to build up distribution function related implementations


Why not store dofs on the entities (Fabien)?


Intent of tensor collection finalize call is to identify a point where we know
everything we ever wanted to know about a field so we can allocate storage.

Dof storage is a big issue; Its fundamental. How do we design an interface that
permits efficient dof storage (and access). Need to know performance behavior, just
as in STL, containers define the complexity of their operations. No one dof storage
layout that will satisfy all application's needs. Note that these notions also
include the issues with how dof storage effects cache coherency. Fabien would
go about implementing this with iRel tables between entities and blobs of dofs
for each entity. If we support multiple container modalities, we will likely 
have to support the ability to change modalities as per applications needs.

iGeom's notion of curvature, normal, tangent could work as a service on top of iField

Will take up parallel and iField tomorrow; also go over iField 'hello world' application.