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1 $Header: /u/gcmpack/models/MITgcmUV/doc/README,v 1.11 1998/07/10 18:48:48 cnh Exp $
2
3
4
5 MITgcmUV Getting Started
6 ========================
7
8 o Introduction
9
10 This note is a guide to using the MIT General Circulation Model Ultra Verstaile
11 implementation, MITgmcUV. MITgcmUV is a Fortran code that implements the
12 algorithm described in Marshall et. al. 1997, Hill, Adcroft, ...
13 The MITgcmUV implementation is designed to work efficiently on all classes
14 of computer platforms. It can be used in both a single processor mode
15 and a parallel processor mode. Parallel processing can be either multi-threaded
16 shared memory such as that found on CRAY T90 machines or it can be multi-process
17 distributed memory. A set of "execution enviroment" support routines are
18 used to allow the same numerical code to run on top of a single-process, multi-threaded
19 or distributed multi-process configuration.
20
21 o Installing
22 To setup the model on a particular computer the code tree must be created
23 and appropriate compile and run scripts set up. For some platforms
24 the necessary scripts are included in the release - in this case follow
25 the steps below:
26
27 1. Extract MITgcmUV from the downloadable archive
28 tar -xvf checkpoint12.tar
29
30 2. Create platform specific make file
31 For example on a Digital UNIX machine the script "genmake.dec" can
32 be used as shown below
33
34 cd bin
35 ../tools/genmake
36 cp Makefile.alpha Makefile ( On Alpha machine)
37
38 3. Now create header file dependency entries
39 make depend
40
41 4. Compile code
42 make
43
44 5. Copy input files
45 cp ../verification/exp2/[a-z]* ../verification/exp2/*bin .
46
47 6. Run baseline test case
48 setenv PARALLEL 1
49 dmpirun -np 2 ../exe/mitgcmuv ( Under Digital UNIX )
50 mpirun.p4shmem ../exe/mitgcmuv -np 2 ( Under Solaris + mpich)
51
52
53 This runs a 4 degree global ocean climatological simulation.
54 By default this code is set to use two porcessors splitting
55 the model domain along the equator. Textual output is written
56 to files STDOUT.* and STDERR.* with one file for each process.
57 Model fileds are written to files suffixed .data and .meta
58 These files are written on a per process basis. The .meta
59 file indicates the location and shape of the subdomain in
60 each .data file.
61
62 o Running
63
64 - Input and output files
65
66 Required files
67 ==============
68 The model is configured to look for two files with fixed names.
69 These files are called
70 "eedata" and "data".
71 The file eedata contains "execution environment" data. At present
72 this consists of a specification of the number of threads to
73 use in X and Y under multithreaded execution.
74
75 - Serial execution
76
77 - Parallel execution. Threads
78 nSx, nSy
79 setenv PARALLEL n
80 nTx=2, nTy=2
81
82 - Parallel execution. MPI
83 mPx, nPy
84 dmpirun
85
86 - Parallel execution. Hybrid
87
88 o Cutomising the code
89
90 Model structure
91 ===============
92 The "numerical" model is contained within a execution
93 environment support wrapper. This wrapper is designed
94 to provide a general framework for grid-point models.
95 MITgcmUV is a specific numerical model that uses the
96 framework.
97 Under this structure the model is split into
98 execution environment support code and conventional
99 numerical model code. The execution environment
100 support code is held under the "eesupp" directory.
101 The grid point model code is held under the
102 "model" directory.
103 Code execution actually starts in the eesupp
104 routines and not in the model routines. For this
105 reason the top level main.F is in the eesupp/src
106 directory. End-users should not need to worry about
107 this level. The top-level routine for the numerical
108 part of the code is in model/src/the_model_main.F.
109
110
111 o References
112 Web sites - HP
113 for doc Digital
114 SGI
115 Sun
116 Linux threads
117 CRAY multitasking
118 PPT notes

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