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$Header: /u/gcmpack/MITgcm/doc/README,v 1.16 2003/08/22 14:30:41 edhill Exp $ |
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================ |
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=== WARNING === |
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================ |
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For MITgcm Users : |
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This directory (MITgcm/doc) does *NOT* contain the primary user |
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documentation for the MITgcm code. We strongly suggest that you forgo |
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the effort of downloading and "building" the documentation in the |
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different formats (pdf, html, etc.) and instead read and/or download |
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the documentation which is conveniently referenced from the main web |
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site at: |
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http://mitgcm.org |
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For MITgcm Developers: |
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If you wish to customize or extend the MITgcm code, this directory |
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contains a "HOWTO" document that tries to explain: |
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+ where the code, documentation, and test/verification |
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data sets are arranged within the CVS repository; |
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+ how to run the verification tests; |
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+ how to get help from the core developers; and |
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+ how to best integrate your work with the overall project. |
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The document is available in SGML source within this directory: |
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devel_HOWTO.sgml |
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and in various formats on our web site: |
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http://mitgcm.org/dev_docs/devel_HOWTO/ |
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====================================================================== |
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=== WARNING : The following has been superseeded by the on-line === |
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=== documentation at: http://mitgcm.org === |
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====================================================================== |
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MITgcmUV Getting Started |
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======================== |
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o Introduction |
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This note is a guide to using the MIT General Circulation Model Ultra Verstaile |
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implementation, MITgmcUV. MITgcmUV is a Fortran code that implements the |
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algorithm described in Marshall et. al. 1997, Hill, Adcroft, ... |
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The MITgcmUV implementation is designed to work efficiently on all classes |
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of computer platforms. It can be used in both a single processor mode |
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and a parallel processor mode. Parallel processing can be either multi-threaded |
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shared memory such as that found on CRAY T90 machines or it can be multi-process |
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distributed memory. A set of "execution enviroment" support routines are |
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used to allow the same numerical code to run on top of a single-process, multi-threaded |
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or distributed multi-process configuration. |
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o Installing |
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To setup the model on a particular computer the code tree must be created |
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and appropriate compile and run scripts set up. For some platforms |
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the necessary scripts are included in the release - in this case follow |
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the steps below: |
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1. Extract MITgcmUV from the downloadable archive |
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tar -xvf cNN.tar |
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2. Create platform specific make file |
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For example on a Digital UNIX machine the script "genmake" can |
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be used as shown below |
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cd bin |
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../tools/genmake |
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cp Makefile.alpha Makefile ( On Alpha machine) |
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3. Now create header file dependency entries |
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make depend |
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4. Compile code |
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make |
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5. To run the model with example data see the "README" in each of |
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the example experiments in ../verification/exp*/ |
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e.g. ../verification/exp2/README |
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o Running |
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- Input and output files |
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Required files |
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============== |
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The model is configured to look for two files with fixed names. |
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These files are called |
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"eedata" and "data". |
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The file eedata contains "execution environment" data. At present |
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this consists of a specification of the number of threads to |
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use in X and Y under multithreaded execution. |
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- Serial execution |
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- Parallel execution. MPI |
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mPx, nPy |
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dmpirun |
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- Parallel execution. Threads |
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nSx, nSy |
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setenv PARALLEL n |
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nTx=2, nTy=2 |
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- Parallel execution. Hybrid |
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o Cutomising the code |
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Model structure |
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=============== |
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The "numerical" model is contained within a execution |
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environment support wrapper. This wrapper is designed |
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to provide a general framework for grid-point models. |
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MITgcmUV is a specific numerical model that uses the |
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framework. |
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Under this structure the model is split into |
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execution environment support code and conventional |
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numerical model code. The execution environment |
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support code is held under the "eesupp" directory. |
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The grid point model code is held under the |
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"model" directory. |
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Code execution actually starts in the eesupp |
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routines and not in the model routines. For this |
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reason the top level main.F is in the eesupp/src |
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directory. End-users should not need to worry about |
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this level. The top-level routine for the numerical |
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part of the code is in model/src/the_model_main.F. |
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o References |
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Web sites - HP |
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for doc Digital |
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SGI |
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Sun |
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Linux threads |
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CRAY multitasking |
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PPT notes |