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1 jmc 1.45 % $Header: /u/gcmpack/manual/s_getstarted/text/getting_started.tex,v 1.44 2010/08/30 23:09:20 jmc Exp $
2 adcroft 1.2 % $Name: $
3 adcroft 1.1
4 adcroft 1.4 %\section{Getting started}
5 adcroft 1.1
6 molod 1.39 We believe the best way to familiarize yourself with the
7 adcroft 1.4 model is to run the case study examples provided with the base
8     version. Information on how to obtain, compile, and run the code is
9 molod 1.39 found here as well as a brief description of the model structure
10     directory and the case study examples. Information is also provided
11     here on how to customize the code when you are ready to try implementing
12     the configuration you have in mind. The code and algorithm
13     are described more fully in chapters \ref{chap:discretization} and
14     \ref{chap:sarch}.
15 adcroft 1.4
16     \section{Where to find information}
17 jmc 1.44 \label{sec:whereToFindInfo}
18 edhill 1.30 \begin{rawhtml}
19     <!-- CMIREDIR:whereToFindInfo: -->
20     \end{rawhtml}
21 adcroft 1.4
22 molod 1.37 There is a web-archived support mailing list for the model that
23 edhill 1.15 you can email at \texttt{MITgcm-support@mitgcm.org} or browse at:
24     \begin{rawhtml} <A href=http://mitgcm.org/mailman/listinfo/mitgcm-support/ target="idontexist"> \end{rawhtml}
25     \begin{verbatim}
26     http://mitgcm.org/mailman/listinfo/mitgcm-support/
27     http://mitgcm.org/pipermail/mitgcm-support/
28     \end{verbatim}
29     \begin{rawhtml} </A> \end{rawhtml}
30 adcroft 1.4
31     \section{Obtaining the code}
32 jmc 1.44 \label{sec:obtainingCode}
33 edhill 1.30 \begin{rawhtml}
34     <!-- CMIREDIR:obtainingCode: -->
35     \end{rawhtml}
36 adcroft 1.1
37 cnh 1.7 MITgcm can be downloaded from our system by following
38     the instructions below. As a courtesy we ask that you send e-mail to us at
39 edhill 1.14 \begin{rawhtml} <A href=mailto:MITgcm-support@mitgcm.org> \end{rawhtml}
40     MITgcm-support@mitgcm.org
41 cnh 1.7 \begin{rawhtml} </A> \end{rawhtml}
42     to enable us to keep track of who's using the model and in what application.
43     You can download the model two ways:
44    
45     \begin{enumerate}
46 cnh 1.9 \item Using CVS software. CVS is a freely available source code management
47 cnh 1.7 tool. To use CVS you need to have the software installed. Many systems
48     come with CVS pre-installed, otherwise good places to look for
49     the software for a particular platform are
50     \begin{rawhtml} <A href=http://www.cvshome.org/ target="idontexist"> \end{rawhtml}
51     cvshome.org
52     \begin{rawhtml} </A> \end{rawhtml}
53     and
54     \begin{rawhtml} <A href=http://www.wincvs.org/ target="idontexist"> \end{rawhtml}
55     wincvs.org
56     \begin{rawhtml} </A> \end{rawhtml}
57     .
58    
59     \item Using a tar file. This method is simple and does not
60     require any special software. However, this method does not
61     provide easy support for maintenance updates.
62    
63     \end{enumerate}
64    
65 cnh 1.27 \subsection{Method 1 - Checkout from CVS}
66 jmc 1.44 \label{sec:cvs_checkout}
67 edhill 1.19
68 adcroft 1.1 If CVS is available on your system, we strongly encourage you to use it. CVS
69     provides an efficient and elegant way of organizing your code and keeping
70     track of your changes. If CVS is not available on your machine, you can also
71     download a tar file.
72    
73 edhill 1.15 Before you can use CVS, the following environment variable(s) should
74     be set within your shell. For a csh or tcsh shell, put the following
75     \begin{verbatim}
76     % setenv CVSROOT :pserver:cvsanon@mitgcm.org:/u/gcmpack
77     \end{verbatim}
78 edhill 1.31 in your \texttt{.cshrc} or \texttt{.tcshrc} file. For bash or sh
79     shells, put:
80 adcroft 1.1 \begin{verbatim}
81 edhill 1.15 % export CVSROOT=':pserver:cvsanon@mitgcm.org:/u/gcmpack'
82 adcroft 1.6 \end{verbatim}
83 edhill 1.20 in your \texttt{.profile} or \texttt{.bashrc} file.
84 adcroft 1.6
85 edhill 1.15
86     To get MITgcm through CVS, first register with the MITgcm CVS server
87     using command:
88 adcroft 1.6 \begin{verbatim}
89 adcroft 1.1 % cvs login ( CVS password: cvsanon )
90     \end{verbatim}
91 edhill 1.15 You only need to do a ``cvs login'' once.
92 adcroft 1.1
93 edhill 1.15 To obtain the latest sources type:
94     \begin{verbatim}
95 jmc 1.45 % cvs co -P MITgcm
96 edhill 1.15 \end{verbatim}
97     or to get a specific release type:
98 adcroft 1.1 \begin{verbatim}
99 jmc 1.45 % cvs co -P -r checkpoint52i_post MITgcm
100 adcroft 1.1 \end{verbatim}
101 jmc 1.45 The CVS command ``\texttt{cvs co}'' is the abreviation of the full-name
102     ``\texttt{cvs checkout}'' command and using the option ``-P'' (\texttt{cvs co -P})
103     will prevent to download unnecessary empty directories.
104    
105 edhill 1.15 The MITgcm web site contains further directions concerning the source
106     code and CVS. It also contains a web interface to our CVS archive so
107     that one may easily view the state of files, revisions, and other
108     development milestones:
109 jmc 1.40 \begin{rawhtml} <A href="http://mitgcm.org/viewvc/MITgcm/MITgcm/" target="idontexist"> \end{rawhtml}
110 edhill 1.15 \begin{verbatim}
111 jmc 1.43 http://mitgcm.org/viewvc/MITgcm/MITgcm/
112 edhill 1.15 \end{verbatim}
113     \begin{rawhtml} </A> \end{rawhtml}
114 adcroft 1.1
115 edhill 1.19 As a convenience, the MITgcm CVS server contains aliases which are
116     named subsets of the codebase. These aliases can be especially
117     helpful when used over slow internet connections or on machines with
118     restricted storage space. Table \ref{tab:cvsModules} contains a list
119     of CVS aliases
120     \begin{table}[htb]
121     \centering
122     \begin{tabular}[htb]{|lp{3.25in}|}\hline
123     \textbf{Alias Name} & \textbf{Information (directories) Contained} \\\hline
124     \texttt{MITgcm\_code} & Only the source code -- none of the verification examples. \\
125     \texttt{MITgcm\_verif\_basic}
126     & Source code plus a small set of the verification examples
127     (\texttt{global\_ocean.90x40x15}, \texttt{aim.5l\_cs}, \texttt{hs94.128x64x5},
128     \texttt{front\_relax}, and \texttt{plume\_on\_slope}). \\
129     \texttt{MITgcm\_verif\_atmos} & Source code plus all of the atmospheric examples. \\
130     \texttt{MITgcm\_verif\_ocean} & Source code plus all of the oceanic examples. \\
131     \texttt{MITgcm\_verif\_all} & Source code plus all of the
132     verification examples. \\\hline
133     \end{tabular}
134     \caption{MITgcm CVS Modules}
135     \label{tab:cvsModules}
136     \end{table}
137 edhill 1.15
138 edhill 1.31 The checkout process creates a directory called \texttt{MITgcm}. If
139     the directory \texttt{MITgcm} exists this command updates your code
140 edhill 1.15 based on the repository. Each directory in the source tree contains a
141 edhill 1.31 directory \texttt{CVS}. This information is required by CVS to keep
142 edhill 1.15 track of your file versions with respect to the repository. Don't edit
143 edhill 1.31 the files in \texttt{CVS}! You can also use CVS to download code
144 edhill 1.15 updates. More extensive information on using CVS for maintaining
145     MITgcm code can be found
146 jmc 1.41 \begin{rawhtml} <A href="http://mitgcm.org/public/using_cvs.html" target="idontexist"> \end{rawhtml}
147 cnh 1.7 here
148     \begin{rawhtml} </A> \end{rawhtml}
149     .
150 edhill 1.19 It is important to note that the CVS aliases in Table
151     \ref{tab:cvsModules} cannot be used in conjunction with the CVS
152     \texttt{-d DIRNAME} option. However, the \texttt{MITgcm} directories
153     they create can be changed to a different name following the check-out:
154     \begin{verbatim}
155 jmc 1.45 % cvs co -P MITgcm_verif_basic
156 edhill 1.19 % mv MITgcm MITgcm_verif_basic
157     \end{verbatim}
158 cnh 1.7
159 edhill 1.19 \subsubsection{Upgrading from an earlier version}
160 adcroft 1.12
161     If you already have an earlier version of the code you can ``upgrade''
162     your copy instead of downloading the entire repository again. First,
163     ``cd'' (change directory) to the top of your working copy:
164     \begin{verbatim}
165     % cd MITgcm
166     \end{verbatim}
167 edhill 1.15 and then issue the cvs update command such as:
168 adcroft 1.12 \begin{verbatim}
169 jmc 1.45 % cvs -q update -d -P -r checkpoint52i_post
170 adcroft 1.12 \end{verbatim}
171 edhill 1.16 This will update the ``tag'' to ``checkpoint52i\_post'', add any new
172 adcroft 1.12 directories (-d) and remove any empty directories (-P). The -q option
173     means be quiet which will reduce the number of messages you'll see in
174     the terminal. If you have modified the code prior to upgrading, CVS
175     will try to merge your changes with the upgrades. If there is a
176     conflict between your modifications and the upgrade, it will report
177     that file with a ``C'' in front, e.g.:
178     \begin{verbatim}
179     C model/src/ini_parms.F
180     \end{verbatim}
181     If the list of conflicts scrolled off the screen, you can re-issue the
182     cvs update command and it will report the conflicts. Conflicts are
183 edhill 1.15 indicated in the code by the delimites ``$<<<<<<<$'', ``======='' and
184     ``$>>>>>>>$''. For example,
185 edhill 1.17 {\small
186 adcroft 1.12 \begin{verbatim}
187     <<<<<<< ini_parms.F
188     & bottomDragLinear,myOwnBottomDragCoefficient,
189     =======
190     & bottomDragLinear,bottomDragQuadratic,
191     >>>>>>> 1.18
192     \end{verbatim}
193 edhill 1.17 }
194 adcroft 1.12 means that you added ``myOwnBottomDragCoefficient'' to a namelist at
195     the same time and place that we added ``bottomDragQuadratic''. You
196     need to resolve this conflict and in this case the line should be
197     changed to:
198 edhill 1.17 {\small
199 adcroft 1.12 \begin{verbatim}
200     & bottomDragLinear,bottomDragQuadratic,myOwnBottomDragCoefficient,
201     \end{verbatim}
202 edhill 1.17 }
203 edhill 1.15 and the lines with the delimiters ($<<<<<<$,======,$>>>>>>$) be deleted.
204 adcroft 1.12 Unless you are making modifications which exactly parallel
205     developments we make, these types of conflicts should be rare.
206    
207     \paragraph*{Upgrading to the current pre-release version}
208    
209     We don't make a ``release'' for every little patch and bug fix in
210     order to keep the frequency of upgrades to a minimum. However, if you
211     have run into a problem for which ``we have already fixed in the
212     latest code'' and we haven't made a ``tag'' or ``release'' since that
213     patch then you'll need to get the latest code:
214     \begin{verbatim}
215 jmc 1.45 % cvs -q update -d -P -A
216 adcroft 1.12 \end{verbatim}
217     Unlike, the ``check-out'' and ``update'' procedures above, there is no
218     ``tag'' or release name. The -A tells CVS to upgrade to the
219     very latest version. As a rule, we don't recommend this since you
220     might upgrade while we are in the processes of checking in the code so
221     that you may only have part of a patch. Using this method of updating
222     also means we can't tell what version of the code you are working
223     with. So please be sure you understand what you're doing.
224    
225 molod 1.37 \subsection{Method 2 - Tar file download}
226 jmc 1.44 \label{sec:conventionalDownload}
227 molod 1.37
228     If you do not have CVS on your system, you can download the model as a
229     tar file from the web site at:
230 jmc 1.40 \begin{rawhtml} <A href=http://mitgcm.org/download/ target="idontexist"> \end{rawhtml}
231 molod 1.37 \begin{verbatim}
232     http://mitgcm.org/download/
233     \end{verbatim}
234     \begin{rawhtml} </A> \end{rawhtml}
235     The tar file still contains CVS information which we urge you not to
236     delete; even if you do not use CVS yourself the information can help
237     us if you should need to send us your copy of the code. If a recent
238     tar file does not exist, then please contact the developers through
239     the
240     \begin{rawhtml} <A href="mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
241     MITgcm-support@mitgcm.org
242     \begin{rawhtml} </A> \end{rawhtml}
243     mailing list.
244    
245 adcroft 1.4 \section{Model and directory structure}
246 edhill 1.30 \begin{rawhtml}
247     <!-- CMIREDIR:directory_structure: -->
248     \end{rawhtml}
249 adcroft 1.1
250 adcroft 1.12 The ``numerical'' model is contained within a execution environment
251     support wrapper. This wrapper is designed to provide a general
252     framework for grid-point models. MITgcmUV is a specific numerical
253     model that uses the framework. Under this structure the model is split
254     into execution environment support code and conventional numerical
255     model code. The execution environment support code is held under the
256 edhill 1.31 \texttt{eesupp} directory. The grid point model code is held under the
257     \texttt{model} directory. Code execution actually starts in the
258     \texttt{eesupp} routines and not in the \texttt{model} routines. For
259     this reason the top-level \texttt{MAIN.F} is in the
260     \texttt{eesupp/src} directory. In general, end-users should not need
261 edhill 1.17 to worry about this level. The top-level routine for the numerical
262 edhill 1.31 part of the code is in \texttt{model/src/THE\_MODEL\_MAIN.F}. Here is
263 edhill 1.17 a brief description of the directory structure of the model under the
264     root tree (a detailed description is given in section 3: Code
265     structure).
266 adcroft 1.1
267     \begin{itemize}
268    
269 edhill 1.31 \item \texttt{doc}: contains brief documentation notes.
270    
271     \item \texttt{eesupp}: contains the execution environment source code.
272     Also subdivided into two subdirectories \texttt{inc} and
273     \texttt{src}.
274 edhill 1.17
275 edhill 1.31 \item \texttt{model}: this directory contains the main source code.
276     Also subdivided into two subdirectories \texttt{inc} and
277     \texttt{src}.
278 edhill 1.17
279 edhill 1.31 \item \texttt{pkg}: contains the source code for the packages. Each
280     package corresponds to a subdirectory. For example, \texttt{gmredi}
281 edhill 1.17 contains the code related to the Gent-McWilliams/Redi scheme,
282 edhill 1.31 \texttt{aim} the code relative to the atmospheric intermediate
283 jmc 1.44 physics. The packages are described in detail in chapter \ref{chap:packagesI}.
284 edhill 1.17
285 edhill 1.31 \item \texttt{tools}: this directory contains various useful tools.
286     For example, \texttt{genmake2} is a script written in csh (C-shell)
287 edhill 1.17 that should be used to generate your makefile. The directory
288 edhill 1.31 \texttt{adjoint} contains the makefile specific to the Tangent
289 edhill 1.17 linear and Adjoint Compiler (TAMC) that generates the adjoint code.
290 molod 1.37 The latter is described in detail in part \ref{chap.ecco}.
291     This directory also contains the subdirectory build\_options, which
292     contains the `optfiles' with the compiler options for the different
293     compilers and machines that can run MITgcm.
294 edhill 1.17
295 edhill 1.31 \item \texttt{utils}: this directory contains various utilities. The
296     subdirectory \texttt{knudsen2} contains code and a makefile that
297 edhill 1.17 compute coefficients of the polynomial approximation to the knudsen
298     formula for an ocean nonlinear equation of state. The
299 edhill 1.31 \texttt{matlab} subdirectory contains matlab scripts for reading
300     model output directly into matlab. \texttt{scripts} contains C-shell
301 edhill 1.17 post-processing scripts for joining processor-based and tiled-based
302 molod 1.37 model output. The subdirectory exch2 contains the code needed for
303     the exch2 package to work with different combinations of domain
304     decompositions.
305 edhill 1.17
306 edhill 1.31 \item \texttt{verification}: this directory contains the model
307 jmc 1.44 examples. See section \ref{sec:modelExamples}.
308 adcroft 1.1
309 molod 1.37 \item \texttt{jobs}: contains sample job scripts for running MITgcm.
310    
311     \item \texttt{lsopt}: Line search code used for optimization.
312    
313     \item \texttt{optim}: Interface between MITgcm and line search code.
314    
315 adcroft 1.1 \end{itemize}
316    
317 cnh 1.26 \section[Building MITgcm]{Building the code}
318 jmc 1.44 \label{sec:buildingCode}
319 edhill 1.30 \begin{rawhtml}
320     <!-- CMIREDIR:buildingCode: -->
321     \end{rawhtml}
322 adcroft 1.4
323 edhill 1.31 To compile the code, we use the \texttt{make} program. This uses a
324     file (\texttt{Makefile}) that allows us to pre-process source files,
325     specify compiler and optimization options and also figures out any
326     file dependencies. We supply a script (\texttt{genmake2}), described
327 jmc 1.44 in section \ref{sec:genmake}, that automatically creates the
328 edhill 1.31 \texttt{Makefile} for you. You then need to build the dependencies and
329 edhill 1.16 compile the code.
330 adcroft 1.4
331 edhill 1.31 As an example, assume that you want to build and run experiment
332     \texttt{verification/exp2}. The are multiple ways and places to
333 edhill 1.16 actually do this but here let's build the code in
334 edhill 1.31 \texttt{verification/exp2/build}:
335 adcroft 1.4 \begin{verbatim}
336 edhill 1.31 % cd verification/exp2/build
337 adcroft 1.4 \end{verbatim}
338 edhill 1.31 First, build the \texttt{Makefile}:
339 adcroft 1.4 \begin{verbatim}
340 edhill 1.16 % ../../../tools/genmake2 -mods=../code
341 adcroft 1.4 \end{verbatim}
342 edhill 1.31 The command line option tells \texttt{genmake} to override model source
343     code with any files in the directory \texttt{../code/}.
344 adcroft 1.4
345 edhill 1.31 On many systems, the \texttt{genmake2} program will be able to
346 edhill 1.16 automatically recognize the hardware, find compilers and other tools
347 edhill 1.31 within the user's path (``\texttt{echo \$PATH}''), and then choose an
348 edhill 1.29 appropriate set of options from the files (``optfiles'') contained in
349 edhill 1.31 the \texttt{tools/build\_options} directory. Under some
350     circumstances, a user may have to create a new ``optfile'' in order to
351     specify the exact combination of compiler, compiler flags, libraries,
352     and other options necessary to build a particular configuration of
353     MITgcm. In such cases, it is generally helpful to read the existing
354     ``optfiles'' and mimic their syntax.
355 edhill 1.16
356     Through the MITgcm-support list, the MITgcm developers are willing to
357     provide help writing or modifing ``optfiles''. And we encourage users
358     to post new ``optfiles'' (particularly ones for new machines or
359 edhill 1.17 architectures) to the
360 edhill 1.34 \begin{rawhtml} <A href="mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
361 edhill 1.17 MITgcm-support@mitgcm.org
362     \begin{rawhtml} </A> \end{rawhtml}
363     list.
364 edhill 1.16
365 edhill 1.31 To specify an optfile to \texttt{genmake2}, the syntax is:
366 adcroft 1.4 \begin{verbatim}
367 edhill 1.16 % ../../../tools/genmake2 -mods=../code -of /path/to/optfile
368 adcroft 1.4 \end{verbatim}
369    
370 edhill 1.31 Once a \texttt{Makefile} has been generated, we create the
371     dependencies with the command:
372 adcroft 1.4 \begin{verbatim}
373     % make depend
374     \end{verbatim}
375 edhill 1.31 This modifies the \texttt{Makefile} by attaching a (usually, long)
376     list of files upon which other files depend. The purpose of this is to
377     reduce re-compilation if and when you start to modify the code. The
378     {\tt make depend} command also creates links from the model source to
379     this directory. It is important to note that the {\tt make depend}
380     stage will occasionally produce warnings or errors since the
381     dependency parsing tool is unable to find all of the necessary header
382     files (\textit{eg.} \texttt{netcdf.inc}). In these circumstances, it
383     is usually OK to ignore the warnings/errors and proceed to the next
384     step.
385 adcroft 1.1
386 edhill 1.31 Next one can compile the code using:
387 adcroft 1.4 \begin{verbatim}
388     % make
389     \end{verbatim}
390 edhill 1.31 The {\tt make} command creates an executable called \texttt{mitgcmuv}.
391 edhill 1.16 Additional make ``targets'' are defined within the makefile to aid in
392 edhill 1.31 the production of adjoint and other versions of MITgcm. On SMP
393     (shared multi-processor) systems, the build process can often be sped
394     up appreciably using the command:
395     \begin{verbatim}
396     % make -j 2
397     \end{verbatim}
398     where the ``2'' can be replaced with a number that corresponds to the
399     number of CPUs available.
400 adcroft 1.4
401     Now you are ready to run the model. General instructions for doing so are
402 jmc 1.44 given in section \ref{sec:runModel}. Here, we can run the model by
403 edhill 1.31 first creating links to all the input files:
404     \begin{verbatim}
405     ln -s ../input/* .
406     \end{verbatim}
407     and then calling the executable with:
408 adcroft 1.4 \begin{verbatim}
409     ./mitgcmuv > output.txt
410     \end{verbatim}
411 edhill 1.31 where we are re-directing the stream of text output to the file
412     \texttt{output.txt}.
413 adcroft 1.4
414 molod 1.35 \subsection{Building/compiling the code elsewhere}
415    
416 jmc 1.44 In the example above (section \ref{sec:buildingCode}) we built the
417 molod 1.35 executable in the {\em input} directory of the experiment for
418     convenience. You can also configure and compile the code in other
419     locations, for example on a scratch disk with out having to copy the
420     entire source tree. The only requirement to do so is you have {\tt
421     genmake2} in your path or you know the absolute path to {\tt
422     genmake2}.
423    
424     The following sections outline some possible methods of organizing
425     your source and data.
426    
427     \subsubsection{Building from the {\em ../code directory}}
428    
429     This is just as simple as building in the {\em input/} directory:
430     \begin{verbatim}
431     % cd verification/exp2/code
432     % ../../../tools/genmake2
433     % make depend
434     % make
435     \end{verbatim}
436     However, to run the model the executable ({\em mitgcmuv}) and input
437     files must be in the same place. If you only have one calculation to make:
438     \begin{verbatim}
439     % cd ../input
440     % cp ../code/mitgcmuv ./
441     % ./mitgcmuv > output.txt
442     \end{verbatim}
443     or if you will be making multiple runs with the same executable:
444     \begin{verbatim}
445     % cd ../
446     % cp -r input run1
447     % cp code/mitgcmuv run1
448     % cd run1
449     % ./mitgcmuv > output.txt
450     \end{verbatim}
451    
452     \subsubsection{Building from a new directory}
453    
454     Since the {\em input} directory contains input files it is often more
455     useful to keep {\em input} pristine and build in a new directory
456     within {\em verification/exp2/}:
457     \begin{verbatim}
458     % cd verification/exp2
459     % mkdir build
460     % cd build
461     % ../../../tools/genmake2 -mods=../code
462     % make depend
463     % make
464     \end{verbatim}
465     This builds the code exactly as before but this time you need to copy
466     either the executable or the input files or both in order to run the
467     model. For example,
468     \begin{verbatim}
469     % cp ../input/* ./
470     % ./mitgcmuv > output.txt
471     \end{verbatim}
472     or if you tend to make multiple runs with the same executable then
473     running in a new directory each time might be more appropriate:
474     \begin{verbatim}
475     % cd ../
476     % mkdir run1
477     % cp build/mitgcmuv run1/
478     % cp input/* run1/
479     % cd run1
480     % ./mitgcmuv > output.txt
481     \end{verbatim}
482    
483     \subsubsection{Building on a scratch disk}
484    
485     Model object files and output data can use up large amounts of disk
486     space so it is often the case that you will be operating on a large
487     scratch disk. Assuming the model source is in {\em ~/MITgcm} then the
488     following commands will build the model in {\em /scratch/exp2-run1}:
489     \begin{verbatim}
490     % cd /scratch/exp2-run1
491     % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
492     -mods=~/MITgcm/verification/exp2/code
493     % make depend
494     % make
495     \end{verbatim}
496     To run the model here, you'll need the input files:
497     \begin{verbatim}
498     % cp ~/MITgcm/verification/exp2/input/* ./
499     % ./mitgcmuv > output.txt
500     \end{verbatim}
501    
502     As before, you could build in one directory and make multiple runs of
503     the one experiment:
504     \begin{verbatim}
505     % cd /scratch/exp2
506     % mkdir build
507     % cd build
508     % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
509     -mods=~/MITgcm/verification/exp2/code
510     % make depend
511     % make
512     % cd ../
513     % cp -r ~/MITgcm/verification/exp2/input run2
514     % cd run2
515     % ./mitgcmuv > output.txt
516     \end{verbatim}
517    
518    
519     \subsection{Using \texttt{genmake2}}
520 jmc 1.44 \label{sec:genmake}
521 molod 1.35
522     To compile the code, first use the program \texttt{genmake2} (located
523     in the \texttt{tools} directory) to generate a Makefile.
524     \texttt{genmake2} is a shell script written to work with all
525     ``sh''--compatible shells including bash v1, bash v2, and Bourne.
526 jmc 1.42 %Internally, \texttt{genmake2} determines the locations of needed
527     %files, the compiler, compiler options, libraries, and Unix tools. It
528     %relies upon a number of ``optfiles'' located in the
529     %\texttt{tools/build\_options} directory.
530     \texttt{genmake2} parses information from the following sources:
531     \begin{description}
532     \item[-] a {\em gemake\_local} file if one is found in the current
533     directory
534     \item[-] command-line options
535     \item[-] an "options file" as specified by the command-line option
536     \texttt{--optfile=/PATH/FILENAME}
537     \item[-] a {\em packages.conf} file (if one is found) with the
538     specific list of packages to compile. The search path for
539     file {\em packages.conf} is, first, the current directory and
540     then each of the "MODS" directories in the given order (see below).
541     \end{description}
542    
543     \subsubsection{Optfiles in \texttt{tools/build\_options} directory:}
544 molod 1.35
545     The purpose of the optfiles is to provide all the compilation options
546     for particular ``platforms'' (where ``platform'' roughly means the
547     combination of the hardware and the compiler) and code configurations.
548     Given the combinations of possible compilers and library dependencies
549     ({\it eg.} MPI and NetCDF) there may be numerous optfiles available
550     for a single machine. The naming scheme for the majority of the
551     optfiles shipped with the code is
552     \begin{center}
553     {\bf OS\_HARDWARE\_COMPILER }
554     \end{center}
555     where
556     \begin{description}
557     \item[OS] is the name of the operating system (generally the
558     lower-case output of the {\tt 'uname'} command)
559     \item[HARDWARE] is a string that describes the CPU type and
560     corresponds to output from the {\tt 'uname -m'} command:
561     \begin{description}
562     \item[ia32] is for ``x86'' machines such as i386, i486, i586, i686,
563     and athlon
564     \item[ia64] is for Intel IA64 systems (eg. Itanium, Itanium2)
565     \item[amd64] is AMD x86\_64 systems
566     \item[ppc] is for Mac PowerPC systems
567     \end{description}
568     \item[COMPILER] is the compiler name (generally, the name of the
569     FORTRAN executable)
570     \end{description}
571    
572     In many cases, the default optfiles are sufficient and will result in
573     usable Makefiles. However, for some machines or code configurations,
574     new ``optfiles'' must be written. To create a new optfile, it is
575     generally best to start with one of the defaults and modify it to suit
576     your needs. Like \texttt{genmake2}, the optfiles are all written
577     using a simple ``sh''--compatible syntax. While nearly all variables
578     used within \texttt{genmake2} may be specified in the optfiles, the
579     critical ones that should be defined are:
580    
581     \begin{description}
582     \item[FC] the FORTRAN compiler (executable) to use
583     \item[DEFINES] the command-line DEFINE options passed to the compiler
584     \item[CPP] the C pre-processor to use
585     \item[NOOPTFLAGS] options flags for special files that should not be
586     optimized
587     \end{description}
588    
589     For example, the optfile for a typical Red Hat Linux machine (``ia32''
590     architecture) using the GCC (g77) compiler is
591     \begin{verbatim}
592     FC=g77
593     DEFINES='-D_BYTESWAPIO -DWORDLENGTH=4'
594     CPP='cpp -traditional -P'
595     NOOPTFLAGS='-O0'
596     # For IEEE, use the "-ffloat-store" option
597     if test "x$IEEE" = x ; then
598     FFLAGS='-Wimplicit -Wunused -Wuninitialized'
599     FOPTIM='-O3 -malign-double -funroll-loops'
600     else
601     FFLAGS='-Wimplicit -Wunused -ffloat-store'
602     FOPTIM='-O0 -malign-double'
603     fi
604     \end{verbatim}
605    
606     If you write an optfile for an unrepresented machine or compiler, you
607     are strongly encouraged to submit the optfile to the MITgcm project
608     for inclusion. Please send the file to the
609     \begin{rawhtml} <A href="mail-to:MITgcm-support@mitgcm.org"> \end{rawhtml}
610     \begin{center}
611     MITgcm-support@mitgcm.org
612     \end{center}
613     \begin{rawhtml} </A> \end{rawhtml}
614     mailing list.
615    
616 jmc 1.42 \subsubsection{Command-line options:}
617    
618 molod 1.35 In addition to the optfiles, \texttt{genmake2} supports a number of
619     helpful command-line options. A complete list of these options can be
620     obtained from:
621     \begin{verbatim}
622     % genmake2 -h
623     \end{verbatim}
624    
625     The most important command-line options are:
626     \begin{description}
627    
628     \item[\texttt{--optfile=/PATH/FILENAME}] specifies the optfile that
629     should be used for a particular build.
630    
631     If no "optfile" is specified (either through the command line or the
632     MITGCM\_OPTFILE environment variable), genmake2 will try to make a
633     reasonable guess from the list provided in {\em
634     tools/build\_options}. The method used for making this guess is
635     to first determine the combination of operating system and hardware
636     (eg. "linux\_ia32") and then find a working FORTRAN compiler within
637     the user's path. When these three items have been identified,
638     genmake2 will try to find an optfile that has a matching name.
639    
640 jmc 1.42 \item[\texttt{--mods='DIR1 DIR2 DIR3 ...'}] specifies a list of
641     directories containing ``modifications''. These directories contain
642     files with names that may (or may not) exist in the main MITgcm
643     source tree but will be overridden by any identically-named sources
644     within the ``MODS'' directories.
645    
646     The order of precedence for this "name-hiding" is as follows:
647     \begin{itemize}
648     \item ``MODS'' directories (in the order given)
649     \item Packages either explicitly specified or provided by default
650     (in the order given)
651     \item Packages included due to package dependencies (in the order
652     that that package dependencies are parsed)
653     \item The "standard dirs" (which may have been specified by the
654     ``-standarddirs'' option)
655     \end{itemize}
656 molod 1.35
657 jmc 1.42 \item[\texttt{--pgroups=/PATH/FILENAME}] specifies the file
658     where package groups are defined. If not set, the package-groups
659     definition will be read from {\em pkg/pkg\_groups}.
660     It also contains the default list of packages (defined
661     as the group ``{\it default\_pkg\_list}'' which is used
662     when no specific package list ({\em packages.conf})
663     is found in current directory or in any "MODS" directory.
664    
665 molod 1.35 \item[\texttt{--pdepend=/PATH/FILENAME}] specifies the dependency file
666     used for packages.
667    
668     If not specified, the default dependency file {\em pkg/pkg\_depend}
669     is used. The syntax for this file is parsed on a line-by-line basis
670     where each line containes either a comment ("\#") or a simple
671     "PKGNAME1 (+|-)PKGNAME2" pairwise rule where the "+" or "-" symbol
672     specifies a "must be used with" or a "must not be used with"
673     relationship, respectively. If no rule is specified, then it is
674     assumed that the two packages are compatible and will function
675     either with or without each other.
676    
677     \item[\texttt{--adof=/path/to/file}] specifies the "adjoint" or
678     automatic differentiation options file to be used. The file is
679     analogous to the ``optfile'' defined above but it specifies
680     information for the AD build process.
681    
682     The default file is located in {\em
683     tools/adjoint\_options/adjoint\_default} and it defines the "TAF"
684     and "TAMC" compilers. An alternate version is also available at
685     {\em tools/adjoint\_options/adjoint\_staf} that selects the newer
686     "STAF" compiler. As with any compilers, it is helpful to have their
687     directories listed in your {\tt \$PATH} environment variable.
688    
689     \item[\texttt{--mpi}] This option enables certain MPI features (using
690     CPP \texttt{\#define}s) within the code and is necessary for MPI
691 jmc 1.44 builds (see Section \ref{sec:mpi-build}).
692 molod 1.35
693     \item[\texttt{--make=/path/to/gmake}] Due to the poor handling of
694     soft-links and other bugs common with the \texttt{make} versions
695     provided by commercial Unix vendors, GNU \texttt{make} (sometimes
696     called \texttt{gmake}) should be preferred. This option provides a
697     means for specifying the make executable to be used.
698    
699     \item[\texttt{--bash=/path/to/sh}] On some (usually older UNIX)
700     machines, the ``bash'' shell is unavailable. To run on these
701     systems, \texttt{genmake2} can be invoked using an ``sh'' (that is,
702     a Bourne, POSIX, or compatible) shell. The syntax in these
703     circumstances is:
704     \begin{center}
705     \texttt{\% /bin/sh genmake2 -bash=/bin/sh [...options...]}
706     \end{center}
707     where \texttt{/bin/sh} can be replaced with the full path and name
708     of the desired shell.
709    
710     \end{description}
711    
712    
713     \subsection{Building with MPI}
714 jmc 1.44 \label{sec:mpi-build}
715 molod 1.35
716     Building MITgcm to use MPI libraries can be complicated due to the
717     variety of different MPI implementations available, their dependencies
718     or interactions with different compilers, and their often ad-hoc
719     locations within file systems. For these reasons, its generally a
720     good idea to start by finding and reading the documentation for your
721     machine(s) and, if necessary, seeking help from your local systems
722     administrator.
723    
724     The steps for building MITgcm with MPI support are:
725     \begin{enumerate}
726    
727     \item Determine the locations of your MPI-enabled compiler and/or MPI
728     libraries and put them into an options file as described in Section
729 jmc 1.44 \ref{sec:genmake}. One can start with one of the examples in:
730 molod 1.35 \begin{rawhtml} <A
731 jmc 1.40 href="http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/build_options/">
732 molod 1.35 \end{rawhtml}
733     \begin{center}
734     \texttt{MITgcm/tools/build\_options/}
735     \end{center}
736     \begin{rawhtml} </A> \end{rawhtml}
737     such as \texttt{linux\_ia32\_g77+mpi\_cg01} or
738     \texttt{linux\_ia64\_efc+mpi} and then edit it to suit the machine at
739     hand. You may need help from your user guide or local systems
740     administrator to determine the exact location of the MPI libraries.
741     If libraries are not installed, MPI implementations and related
742     tools are available including:
743     \begin{itemize}
744     \item \begin{rawhtml} <A
745     href="http://www-unix.mcs.anl.gov/mpi/mpich/">
746     \end{rawhtml}
747     MPICH
748     \begin{rawhtml} </A> \end{rawhtml}
749    
750     \item \begin{rawhtml} <A
751     href="http://www.lam-mpi.org/">
752     \end{rawhtml}
753     LAM/MPI
754     \begin{rawhtml} </A> \end{rawhtml}
755    
756     \item \begin{rawhtml} <A
757     href="http://www.osc.edu/~pw/mpiexec/">
758     \end{rawhtml}
759     MPIexec
760     \begin{rawhtml} </A> \end{rawhtml}
761     \end{itemize}
762    
763     \item Build the code with the \texttt{genmake2} \texttt{-mpi} option
764 jmc 1.44 (see Section \ref{sec:genmake}) using commands such as:
765 molod 1.35 {\footnotesize \begin{verbatim}
766     % ../../../tools/genmake2 -mods=../code -mpi -of=YOUR_OPTFILE
767     % make depend
768     % make
769     \end{verbatim} }
770    
771     \item Run the code with the appropriate MPI ``run'' or ``exec''
772     program provided with your particular implementation of MPI.
773     Typical MPI packages such as MPICH will use something like:
774     \begin{verbatim}
775     % mpirun -np 4 -machinefile mf ./mitgcmuv
776     \end{verbatim}
777     Sightly more complicated scripts may be needed for many machines
778     since execution of the code may be controlled by both the MPI
779     library and a job scheduling and queueing system such as PBS,
780     LoadLeveller, Condor, or any of a number of similar tools. A few
781     example scripts (those used for our \begin{rawhtml} <A
782 jmc 1.41 href="http://mitgcm.org/public/testing.html"> \end{rawhtml}regular
783 molod 1.35 verification runs\begin{rawhtml} </A> \end{rawhtml}) are available
784     at:
785     \begin{rawhtml} <A
786 jmc 1.41 href="http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/example_scripts/">
787     \end{rawhtml}
788     {\footnotesize \tt
789     http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/example\_scripts/ }
790     \begin{rawhtml} </A> \end{rawhtml}
791     or at:
792     \begin{rawhtml} <A
793 jmc 1.40 href="http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/test_scripts/">
794 molod 1.35 \end{rawhtml}
795     {\footnotesize \tt
796 jmc 1.40 http://mitgcm.org/viewvc/MITgcm/MITgcm\_contrib/test\_scripts/ }
797 molod 1.35 \begin{rawhtml} </A> \end{rawhtml}
798    
799     \end{enumerate}
800    
801     An example of the above process on the MITgcm cluster (``cg01'') using
802     the GNU g77 compiler and the mpich MPI library is:
803    
804     {\footnotesize \begin{verbatim}
805     % cd MITgcm/verification/exp5
806     % mkdir build
807     % cd build
808     % ../../../tools/genmake2 -mpi -mods=../code \
809     -of=../../../tools/build_options/linux_ia32_g77+mpi_cg01
810     % make depend
811     % make
812     % cd ../input
813     % /usr/local/pkg/mpi/mpi-1.2.4..8a-gm-1.5/g77/bin/mpirun.ch_gm \
814     -machinefile mf --gm-kill 5 -v -np 2 ../build/mitgcmuv
815     \end{verbatim} }
816 adcroft 1.4
817 cnh 1.26 \section[Running MITgcm]{Running the model in prognostic mode}
818 jmc 1.44 \label{sec:runModel}
819 edhill 1.30 \begin{rawhtml}
820     <!-- CMIREDIR:runModel: -->
821     \end{rawhtml}
822 adcroft 1.4
823 jmc 1.44 If compilation finished succesfully (section \ref{sec:buildingCode})
824 edhill 1.23 then an executable called \texttt{mitgcmuv} will now exist in the
825     local directory.
826 adcroft 1.1
827 edhill 1.29 To run the model as a single process (\textit{ie.} not in parallel)
828     simply type:
829 adcroft 1.1 \begin{verbatim}
830 adcroft 1.4 % ./mitgcmuv
831 adcroft 1.1 \end{verbatim}
832 adcroft 1.4 The ``./'' is a safe-guard to make sure you use the local executable
833     in case you have others that exist in your path (surely odd if you
834     do!). The above command will spew out many lines of text output to
835     your screen. This output contains details such as parameter values as
836     well as diagnostics such as mean Kinetic energy, largest CFL number,
837     etc. It is worth keeping this text output with the binary output so we
838 edhill 1.31 normally re-direct the \texttt{stdout} stream as follows:
839 adcroft 1.1 \begin{verbatim}
840 adcroft 1.4 % ./mitgcmuv > output.txt
841 adcroft 1.1 \end{verbatim}
842 edhill 1.29 In the event that the model encounters an error and stops, it is very
843     helpful to include the last few line of this \texttt{output.txt} file
844     along with the (\texttt{stderr}) error message within any bug reports.
845 adcroft 1.1
846 edhill 1.31 For the example experiments in \texttt{verification}, an example of the
847     output is kept in \texttt{results/output.txt} for comparison. You can
848     compare your \texttt{output.txt} with the corresponding one for that
849 edhill 1.29 experiment to check that the set-up works.
850 adcroft 1.1
851    
852    
853 adcroft 1.4 \subsection{Output files}
854 adcroft 1.1
855 edhill 1.31 The model produces various output files and, when using \texttt{mnc},
856     sometimes even directories. Depending upon the I/O package(s)
857     selected at compile time (either \texttt{mdsio} or \texttt{mnc} or
858     both as determined by \texttt{code/packages.conf}) and the run-time
859     flags set (in \texttt{input/data.pkg}), the following output may
860     appear.
861 edhill 1.29
862    
863     \subsubsection{MDSIO output files}
864    
865     The ``traditional'' output files are generated by the \texttt{mdsio}
866     package. At a minimum, the instantaneous ``state'' of the model is
867     written out, which is made of the following files:
868 adcroft 1.1
869     \begin{itemize}
870 edhill 1.34 \item \texttt{U.00000nIter} - zonal component of velocity field (m/s
871     and positive eastward).
872 adcroft 1.1
873 edhill 1.34 \item \texttt{V.00000nIter} - meridional component of velocity field
874     (m/s and positive northward).
875 adcroft 1.1
876 edhill 1.34 \item \texttt{W.00000nIter} - vertical component of velocity field
877     (ocean: m/s and positive upward, atmosphere: Pa/s and positive
878     towards increasing pressure i.e. downward).
879 adcroft 1.1
880 edhill 1.34 \item \texttt{T.00000nIter} - potential temperature (ocean:
881     $^{\circ}\mathrm{C}$, atmosphere: $^{\circ}\mathrm{K}$).
882 adcroft 1.1
883 edhill 1.34 \item \texttt{S.00000nIter} - ocean: salinity (psu), atmosphere: water
884     vapor (g/kg).
885 adcroft 1.1
886 edhill 1.34 \item \texttt{Eta.00000nIter} - ocean: surface elevation (m),
887     atmosphere: surface pressure anomaly (Pa).
888 adcroft 1.1 \end{itemize}
889    
890 edhill 1.31 The chain \texttt{00000nIter} consists of ten figures that specify the
891 edhill 1.34 iteration number at which the output is written out. For example,
892     \texttt{U.0000000300} is the zonal velocity at iteration 300.
893 adcroft 1.1
894     In addition, a ``pickup'' or ``checkpoint'' file called:
895    
896     \begin{itemize}
897 edhill 1.31 \item \texttt{pickup.00000nIter}
898 adcroft 1.1 \end{itemize}
899    
900     is written out. This file represents the state of the model in a condensed
901     form and is used for restarting the integration. If the C-D scheme is used,
902     there is an additional ``pickup'' file:
903    
904     \begin{itemize}
905 edhill 1.31 \item \texttt{pickup\_cd.00000nIter}
906 adcroft 1.1 \end{itemize}
907    
908     containing the D-grid velocity data and that has to be written out as well
909     in order to restart the integration. Rolling checkpoint files are the same
910     as the pickup files but are named differently. Their name contain the chain
911 edhill 1.31 \texttt{ckptA} or \texttt{ckptB} instead of \texttt{00000nIter}. They can be
912 adcroft 1.1 used to restart the model but are overwritten every other time they are
913     output to save disk space during long integrations.
914    
915 edhill 1.29 \subsubsection{MNC output files}
916    
917     Unlike the \texttt{mdsio} output, the \texttt{mnc}--generated output
918     is usually (though not necessarily) placed within a subdirectory with
919 molod 1.38 a name such as \texttt{mnc\_test\_\${DATE}\_\${SEQ}}.
920 edhill 1.29
921 adcroft 1.4 \subsection{Looking at the output}
922 adcroft 1.1
923 edhill 1.29 The ``traditional'' or mdsio model data are written according to a
924     ``meta/data'' file format. Each variable is associated with two files
925 edhill 1.31 with suffix names \texttt{.data} and \texttt{.meta}. The
926     \texttt{.data} file contains the data written in binary form
927     (big\_endian by default). The \texttt{.meta} file is a ``header'' file
928 edhill 1.29 that contains information about the size and the structure of the
929 edhill 1.31 \texttt{.data} file. This way of organizing the output is particularly
930 edhill 1.29 useful when running multi-processors calculations. The base version of
931     the model includes a few matlab utilities to read output files written
932     in this format. The matlab scripts are located in the directory
933 edhill 1.31 \texttt{utils/matlab} under the root tree. The script \texttt{rdmds.m}
934 edhill 1.29 reads the data. Look at the comments inside the script to see how to
935     use it.
936 adcroft 1.1
937 adcroft 1.4 Some examples of reading and visualizing some output in {\em Matlab}:
938     \begin{verbatim}
939     % matlab
940     >> H=rdmds('Depth');
941     >> contourf(H');colorbar;
942     >> title('Depth of fluid as used by model');
943    
944     >> eta=rdmds('Eta',10);
945     >> imagesc(eta');axis ij;colorbar;
946     >> title('Surface height at iter=10');
947    
948     >> eta=rdmds('Eta',[0:10:100]);
949     >> for n=1:11; imagesc(eta(:,:,n)');axis ij;colorbar;pause(.5);end
950     \end{verbatim}
951 adcroft 1.1
952 edhill 1.31 Similar scripts for netCDF output (\texttt{rdmnc.m}) are available and
953     they are described in Section \ref{sec:pkg:mnc}.
954    
955 molod 1.38 The MNC output files are all in the ``self-describing'' netCDF
956     format and can thus be browsed and/or plotted using tools such as:
957     \begin{itemize}
958     \item \texttt{ncdump} is a utility which is typically included
959     with every netCDF install:
960     \begin{rawhtml} <A href="http://www.unidata.ucar.edu/packages/netcdf/"> \end{rawhtml}
961     \begin{verbatim}
962     http://www.unidata.ucar.edu/packages/netcdf/
963     \end{verbatim}
964     \begin{rawhtml} </A> \end{rawhtml} and it converts the netCDF
965     binaries into formatted ASCII text files.
966    
967     \item \texttt{ncview} utility is a very convenient and quick way
968     to plot netCDF data and it runs on most OSes:
969     \begin{rawhtml} <A href="http://meteora.ucsd.edu/~pierce/ncview_home_page.html"> \end{rawhtml}
970     \begin{verbatim}
971     http://meteora.ucsd.edu/~pierce/ncview_home_page.html
972     \end{verbatim}
973     \begin{rawhtml} </A> \end{rawhtml}
974    
975     \item MatLAB(c) and other common post-processing environments provide
976     various netCDF interfaces including:
977     \begin{rawhtml} <A href="http://mexcdf.sourceforge.net/"> \end{rawhtml}
978     \begin{verbatim}
979     http://mexcdf.sourceforge.net/
980     \end{verbatim}
981     \begin{rawhtml} </A> \end{rawhtml}
982     \begin{rawhtml} <A href="http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html"> \end{rawhtml}
983     \begin{verbatim}
984     http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html
985     \end{verbatim}
986     \begin{rawhtml} </A> \end{rawhtml}
987     \end{itemize}
988    

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