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| 3 | <meta http-equiv="CONTENT-TYPE" content="text/html; charset=windows-1252"><title>PALM |
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| 4 | chapter 3.0</title> <meta name="GENERATOR" content="StarOffice 7 (Win32)"> <meta name="AUTHOR" content="Marcus Oliver Letzel"> <meta name="CREATED" content="20040723;15213734"> <meta name="CHANGED" content="20041112;13170538"> <meta name="KEYWORDS" content="parallel LES model"> <style> |
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| 8 | </style></head> |
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| 9 | |
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| 10 | <body style="direction: ltr;" lang="en-US"><h2 style="font-style: normal; line-height: 100%;"><font size="4">3.0 |
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| 11 | Execution of model runs</font></h2> |
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| 12 | <p style="line-height: 100%;">Given that the model was |
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| 13 | installed by the user (look at <a href="chapter_5.0.html">chapter |
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| 14 | 5.0</a>) and that it is clear, which phenomenon is to be |
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| 15 | simulated, |
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| 16 | there is a whole set of questions which must be answered before |
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| 17 | executing |
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| 18 | the actual application run, e.g.: </p> |
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| 19 | <ul> <li> <p style="margin-bottom: 0cm; font-style: normal; line-height: 100%;">How |
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| 20 | large does the model domain have to be and what grid size does |
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| 21 | phenomenon to be simulated require? </p> </li> <li> |
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| 22 | <p style="margin-bottom: 0cm; font-style: normal; line-height: 100%;">How |
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| 23 | long is the time which should be simulated, i.e. which typical time |
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| 24 | scale does the phenomenon have? </p> </li> <li> <p style="margin-bottom: 0cm; font-style: normal; line-height: 100%;">Which |
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| 25 | boundary conditions and initial conditions are to be selected? </p> |
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| 26 | </li> <li> <p style="font-style: normal; line-height: 100%;">Which model |
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| 27 | output data are necessary at which points in time, in order to be able |
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| 28 | to analyze the phenomenon afterwards? </p> </li> |
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| 29 | </ul><p style="line-height: 100%;">The answers to |
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| 30 | these questions |
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| 31 | substantially determine the choice of values for the most important |
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| 32 | model parameters, with which the model run is steered. All possible |
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| 33 | parameters are described in chapters <a href="chapter_4.1.html">4.1</a>, |
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| 34 | <a href="chapter_4.2.html">4.2</a> |
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| 35 | and <a href="chapter_4.3.html">4.3</a>. |
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| 36 | The basic steering of the model with these parameters is explained in |
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| 37 | the introduction to <a href="chapter_4.0.html">chapter |
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| 38 | 4</a>. The user will rarely use all model parameters, since many |
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| 39 | are |
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| 40 | preset with consistent default values and therefore do not have to be |
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| 41 | changed by the user. Some of the most important parameters are not |
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| 42 | preset with default values and must be adjusted by the user in each |
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| 43 | case. Such a typical, minimum parameter set is described in <a href="chapter_4.4.html">chapter |
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| 44 | 4.4</a>. For the subsequent analysis of model runs, graphical |
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| 45 | visualization of model data is particularly important. <a href="chapter_4.5.html">Chapter |
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| 46 | 4.5</a> describes, how such outputs are produced with the model. </p> |
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| 47 | <p style="line-height: 100%;">The selected parameters and |
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| 48 | their values |
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| 49 | have to be supplied to the model as an input file. The |
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| 50 | structure of this file is described in the introduction to <a href="chapter_4.0.html">chapter |
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| 51 | 4</a>. The data, produced by the model, are located in a number |
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| 52 | of |
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| 53 | different output files. The model works with relative file names |
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| 54 | (i.e. without absolute path information). Thus all input and output |
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| 55 | files are |
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| 56 | expected and put in the directory, in which the actual model (the |
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| 57 | executable program created from the FORTRAN source code) is started |
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| 58 | (but also see next paragraph). |
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| 59 | All user-relevant input and output files are described in <a href="chapter_3.4.html">chapter |
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| 60 | 3.4</a>. </p> |
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| 61 | <p style="line-height: 100%;">The actual model (the |
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| 62 | executable |
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| 63 | program) is not started directly via the user, but with the help of |
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| 64 | the shell script <a href="http://www.muk.uni-hannover.de/institut/software/mrun_beschreibung.html">mrun</a>,which |
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| 65 | can be called by the user. This script takes over the entire pre- and |
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| 66 | postprocessing work, which is necessary for a model run. In addition |
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| 67 | to this, it generates e.g. automatically batch jobs for model runs on |
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| 68 | remote computers, provides for the appropriate file transfers of the |
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| 69 | input and output files to these computers, secures data on existing |
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| 70 | archives systems, starts if necessary restart jobs, and much more. |
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| 71 | <span style="font-weight: bold;">mrun</span> allows |
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| 72 | to specify |
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| 73 | individual path names for each simulation and |
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| 74 | for the different types of input/output files. The start of model runs |
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| 75 | with <b>mrun</b> is described in <a href="chapter_3.1.html">chapter |
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| 76 | 3.1</a>. </p> |
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| 77 | <p style="line-height: 100%;">The implementation of user |
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| 78 | code |
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| 79 | extensions in |
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| 80 | the model is made possible by a set of defined interfaces. You will |
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| 81 | find references to the programming of such extensions in <a href="chapter_3.5.html">chapter |
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| 82 | 3.5</a>. Frequently errors arise during the execution of the |
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| 83 | model |
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| 84 | after such changes, which can often be found only by interactive |
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| 85 | model steering and error tracing (debugging), which are described in |
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| 86 | <a href="chapter_3.6.html">chapter |
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| 87 | 3.6</a>. </p> |
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| 88 | <hr><p style="font-style: normal; line-height: 100%;"><br> |
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| 89 | <font color="#000080"><font color="#000080"><a href="chapter_2.0.html"><font color="#000080"><img src="left.gif" name="Grafik1" align="bottom" border="2" height="32" width="32"></font></a><a href="index.html"><font color="#000080"><img src="up.gif" name="Grafik2" align="bottom" border="2" height="32" width="32"></font></a><a href="chapter_3.1.html"><font color="#000080"><img src="right.gif" name="Grafik3" align="bottom" border="2" height="32" width="32"></font></a></font></font><br> |
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| 90 | </p><p style="font-style: normal; line-height: 100%;"><span style="font-style: italic;">Last change:</span> |
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| 91 | $Id: chapter_3.0.html 62 2007-03-13 02:52:40Z raasch $<br> |
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| 92 | </p></body></html> |
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