ESMF Requirements Overview

1
ESMF Requirements Overview

• Chris Hill, MIT
• cnh_at_plume.mit.edu

2
Current Status

• Contributions drawn from applications of all
  groups
• ?200 pages of raw material, http//www.esmf.ucar.e
  du/development
• Seeking community input, comments and feedback

3
What are Requirements?

• Prelude to detailed design
• What to do, not precisely how to do it
• Set scope of what gets built
• Draft ESMF requirements
• Glossary of common terms ? common language
• General requirements
• Ten chapters (so far) of detailed requirements
  for key concepts.

4
Table of Contents
ESMF Superstructure
User Code
ESMF Infrastructure
Fields Grids
Utilities
BLAS, MPI, NetCDF,

• Pages 1 - 17

5
Introduction and Glossary

• Introduction (pages 19-23)
• ESMF architecture overview
• Glossary of terms (pages 23-27)
• Component A large-scale computational entity
  associated with a particular physical process or
  computational function, such as a land model.
  Components may be generic or user-supplied. See
  also gridded component, coupler component.
• Application A coherent computational entity run
  as a single executable or set of communicating
  executables. It typically consists of a set of
  interacting components.

6
General Requirements GR

• Requirements that are framework wide, examples
• language interfaces F90, C, C - GR1.1.n
• OS compatibility/hardware neutrality unices -
  GR1.2.n
• performance and scalability low-overhead lt10 -
  GR1.3
• Apply to all areas that ESMF covers
• Pages 29-33

7
Superstructure

• Control
• Coupler and Gridded Components

8
Control - CTL

• Connecting components, mapping components to
  resources
• Requirements
• SPMD and MPMD support - CTL1.1 CTL1.2
• Control of resources - CTL2 3
• Component startup and shutdown CTL4 5
• Component interactions CTL7, 8 9
• Pages 34-53

9
Coupler and Gridded Components - CGC

• Containers for user code
• Requirements
• Creation, deletion, start, stop - CGC2
• Exports and imports - CGC2
• Gridded and coupler flavors CGC4 5
• Pages 54-63
• Superstructure (CTL and CGC) QA this afternoon

10
Infrastructure Fields and Grids

• Fields
• Physical Grids
• Distributed Grids
• Regridding

11
Fields- FLD

• Containers for component data
• Requirements
• Creation, deletion - FLD1
• Attributes, metadata FLD1
• Collections of fields, bundles - FLD2
• Pages 64-75

12
Physical Grids- PG

• Discrete representations of a continuous
  coordinate system
• Requirements
• Structured (f-diff, f-vol, wave) - PG1
• Horizontal specification PG1.1
• Vertical specification PG1.2
• Locations Streams (obs, lagrangian), background
  grid PG2
• Topologies (cartesian, lat-lon, gen. orth),
  staggering, - PG3
• Pages 76-102

13
Distributed Grids- DG

• Decomposition based on grids. Source of scalable
  parallelism.
• Requirements
• Setup 1-D, 2-D decomposition, periodicity - DG1
• Queries ranges, topology, ownership DG2
• Operations halo, transpose/redistribute,
  aggregate communication, sums and checksums
  DG4-10
• Individual grid specifics spectral, regioned
  DG14
• Pages 103-126

14
Regridding- RG

• Interpolation, redistribution/transposition.
• Requirements
• Setup create, delete, query - RG1
• Algorithms conservation, accuracy order RG3
• Extensibility user extensions RG3
• Pages 127-137
• Fields and Grids (FLD, PG, DG, RG) QA this
  afternoon.

15
Infrastructure Utilities

• Time manangement
• Performance profiling
• Log
• I/O

16
Time Management- TMG

• Common simulated-time
• Requirements
• Units, resolution, range - TMG1
• Calendars TMG2
• Clocks and alarms - TMG3, TMG4
• Pages 138-156

17
Performance Profiling- PP

• Built-in capabilities for tracking resource use
• Requirements
• Timers - PP1
• Hardware counters PP2
• Process and thread granularity - PP3
• Queries PP4
• Pages 157-161

18
Log- LG

• Built-in capabilities for recording progress,
  events
• Requirements
• Interface LG2
• Parallelism LG5, LG6
• Pages 162-164

19
I/O- IO

• Compatibility with standard disk I/O mechanisms
• Requirements
• Metadata IO1
• Standard formats and libraries IO2
• Parallelism IO3
• Pages 165-175
• Utilities (TMG, PP, LG, IO) QA this afternoon.