NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH May 15, 2003 Nancy Collins, NCAR 2nd Community Meeting, Princeton, NJ Earth System

May 15, 2003

NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH

Nancy Collins, NCAR

2nd Community Meeting, Princeton, NJ

Earth System Modeling Framework Superstructure

NSIPP Seasonal ForecastNCAR/LANL CCSM

NCEP Forecast

GFDL FMS SuiteMITgcm

NASA GSFC PSAS

May 15, 2003


Superstructure Outline

• Superstructure Classes• Design Principles• Object Details• Adoption Preparation

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ESMF Class Structure

MachineModel

Layout

DistGridPhysGrid

State

Bundle

GriddedComponent

Array

Utilities: TimeMgr, Config, LogErr, I/O etc.

F90

Superstructure

Infrastructure

Field

Grid

Regrid

Comm

Data Communications

Route

CouplerComponent

C++

ApplicationComponent

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Superstructure Classes

GriddedComponent(s)

Array

Computation

Data

ApplicationComponent

FieldBundleState

State

CouplerComponent(s)

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Design Principles:Scalable ApplicationsSince each ESMF application is also a component, entire ESMF applications may be treated as Gridded Components and nested within larger applications.

climate_comp

ocn_comp atm_comp

ocn2atm_coupler

atm_phys

phys2dyn_coupler

atm_dynPE

Example: atmospheric application containing multiplecoupled components within a larger climate application

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Design Principles:Local CommunicationAll inter-component communication within ESMF is local.

climate_comp

ocn_comp atm_comp

atm_phys

phys2dyn_coupler

atm_dynPE

atm2ocn _coupler

This means:

Coupler Components must be defined on the union of the PEs of all the components that they couple.

In this example, in order to send data from the ocean component to the atmosphere, the Coupler mediates the send.

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Design Principles:Import/Export StatesGridded Components do not have access to the internals of other Gridded Components. They have 2 options for exchanging data with other Components; the first is to receive Import and Export States as arguments.

coupler

ocn_componentsubroutine ocn_run(comp, &

ImportState,ExportState, Clock, rc)

atm_componentsubroutine atm_run(comp, &

ImportState,ExportState, Clock, rc)

States contain flags for “is required”, “isvalid”, “is ready”, etc.

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Design Principles:Transforms and StatesGridded Components using Transforms do not have to return control to a higher level component to send or receive State data from another component. They can receive function pointers which are methods that can be called on the states.

coupler

ocn_componentcall ESMF_StateXform(ex_state, &

xform)

atm_componentcall ESMF_StateXform(xform, &

im_state)

transformcall ESMF_CompRun(atm, xform)call ESMF_CompRun(ocn, xform)

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Design Principles:Registration ProcessComponents must provide a single externally visible entry point which will register the other entry points with the Framework. Components can:

- Register one or more Initialization, Run, Finalize, and Checkpoint entry points.

- Register a private data block which can contain all data associated with this instantiation of the Component; particularly useful when running ensembles.

Higher level Comp

cmp_register() cmp_run() cmp_final()cmp_init()

ESMF Framework Services

Public subroutinePrivate subroutine

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Gridded Component

• Computational model, data assimilation code• Associated DELayout object• Optional associated Grid• Register entry point• Import and Export States for:

– Initialization phase– Run phase– Finalize phase

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Coupler Component

• Data transformation code:– Regridding, Unit conversions, Conservation of

quantities, Accumulation• Register entry point• Nested States for:

– Initialization phase– Run phase– Finalize phase

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Application Component

• Main program• Container for single Component• Creates Gridded Component• Calls Registration routine• Read configuration files, create Grid, create

Main Clock, supply dummy Import/Export States for subcomponents.

• Single call to Init, Run, and Finalize routine

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State Objects

• Annotated List of other ESMF objects• Bundles, Fields, Arrays, and other States• Flags for “needed”, “ready”, “valid”• Named objects, CF conventions for Fields• Import/Export States for Gridded Comps• Single State for Coupler Comps

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Transform Objects

• Concurrent Components can exchange States without returning to calling code

• Coupler’s role is to provide Transform object which contains subroutine pointer

• Subroutine transforms data from Export State of one component to Import State of another

• Needs higher level of control/sequencing

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ESMF User Environments

•Languages: F90 (predominately), C++•Systems: Unix/Linux variants (inc IBM, SGI, Compaq, Linux clusters, Mac OS X)•Memory: MPI, PThreads/SMP•Execution: Sequential and Concurrent•Runtime system: LoadLeveler, poe, bsub, mpirun

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ESMF Component Characteristics• Components can create other Components• Nested parent/child relationship• Annotated States contain all data passed

between components• Data objects use CF name conventions• Can be created dynamically • Initialization/Run/Finalize/Checkpoint

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Adopting ESMF

• See ESMF User’s Guide, Section 12• Self-contained Components

– Subroutines for major phases– States for Import/Export– Private data

• What results can be exported up to higher level applications which might be built

May 15, 2003


ESMF Adoption Curve:Incremental Path• Minimum: Component

interfaces/subroutines, Data in Fields, Time via Clocks, information exchange via States

• Plus any or all of: Time Mgr with Internal Clocks, Data in ESMF Fields/Grids, Regrid/Halo of Fields, Logging, Configuration files

Documents

NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH May 15, 2003 Nancy Collins, NCAR 2nd Community Meeting, Princeton, NJ Earth System