source: branches/2017/dev_merge_2017/DOC/tex_sub/annex_D.tex @ 9393

Last change on this file since 9393 was 9393, checked in by nicolasmartin, 3 years ago

Cleaning of section headings, reinstating the index by mixing \np and \forcode macros, continued conversion of source code inclusions

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1\documentclass[../tex_main/NEMO_manual]{subfiles}
2\begin{document}
3% ================================================================
4% Appendix D Ñ Coding Rules
5% ================================================================
6\chapter{Coding Rules}
7\label{Apdx_D}
8\minitoc
9
10\newpage
11$\ $\newline    % force a new ligne
12$\ $\newline    % force a new ligne
13
14
15A "model life" is more than ten years. Its software, composed of a few
16hundred modules, is used by many people who are scientists or students
17and do not necessarily know every aspect of computing very well.
18Moreover, a well thought-out program is easier to read and understand,
19less difficult to modify, produces fewer bugs and is easier to maintain.
20Therefore, it is essential that the model development follows some rules :
21
22- well planned and designed
23
24- well written
25
26- well documented (both on- and off-line)
27
28- maintainable
29
30- easily portable
31
32- flexible.
33
34To satisfy part of these aims, \NEMO is written with a coding standard which
35is close to the ECMWF rules, named DOCTOR \citep{Gibson_TR86}.
36These rules present some advantages like :
37
38- to provide a well presented program
39
40- to use rules for variable names which allow recognition of their type
41(integer, real, parameter, local or shared variables, etc. ).
42
43This facilitates both the understanding and the debugging of an algorithm.
44
45% ================================================================
46% The program structure
47% ================================================================
48\section{Program structure}
49\label{Apdx_D_structure}
50
51Each program begins with a set of headline comments containing :
52
53- the program title
54
55- the purpose of the routine
56
57- the method and algorithms used
58
59- the detail of input and output interfaces
60
61- the external routines and functions used (if they exist)
62
63- references (if they exist)
64
65- the author name(s), the date of creation and any updates.
66
67- Each program is split into several well separated sections and
68sub-sections with an underlined title and specific labelled statements.
69
70- A program has not more than 200 to 300 lines.
71
72A template of a module style can be found on the NEMO depository
73in the following file : NEMO/OPA\_SRC/module\_example.
74% ================================================================
75% Coding conventions
76% ================================================================
77\section{Coding conventions}
78\label{Apdx_D_coding}
79
80- Use of the universal language \textsc{Fortran} 90, and try to avoid obsolescent
81features like statement functions, do not use GO TO and EQUIVALENCE statements.
82
83- A continuation line begins with the character {\&} indented by three spaces
84compared to the previous line, while the previous line ended with the character {\&}.
85
86- All the variables must be declared. The code is usually compiled with implicit none.
87 
88- Never use continuation lines in the declaration of a variable. When searching a
89variable in the code through a \textit{grep} command, the declaration line will be found.
90
91- In the declaration of a PUBLIC variable, the comment part at the end of the line
92should start with the two characters "\verb?!:?". the following UNIX command, \\
93\verb?grep var_name *90 \ grep \!: ? \\
94will display the module name and the line where the var\_name declaration is.
95
96- Always use a three spaces indentation in DO loop, CASE, or IF-ELSEIF-ELSE-ENDIF
97statements.
98
99- use a space after a comma, except when it appears to separate the indices of an array.
100
101- use call to ctl\_stop routine instead of just a STOP.
102
103
104\newpage
105% ================================================================
106% Naming Conventions
107% ================================================================
108\section{Naming conventions}
109\label{Apdx_D_naming}
110
111The purpose of the naming conventions is to use prefix letters to classify
112model variables. These conventions allow the variable type to be easily
113known and rapidly identified. The naming conventions are summarised
114in the Table below:
115
116
117%--------------------------------------------------TABLE--------------------------------------------------
118\begin{table}[htbp]  \label{Tab_VarName}
119\begin{center}
120\begin{tabular}{|p{45pt}|p{35pt}|p{45pt}|p{40pt}|p{40pt}|p{40pt}|p{40pt}|p{40pt}|}
121\hline  Type \par / Status &   integer&   real&   logical &   character  & structure &   double \par precision&   complex \\ 
122\hline
123public  \par or  \par module variable& 
124\textbf{m n} \par \textit{but not} \par \textbf{nn\_ np\_}& 
125\textbf{a b e f g h o q r} \par \textbf{t} \textit{to} \textbf{x} \par but not \par \textbf{fs rn\_}& 
126\textbf{l} \par \textit{but not} \par \textbf{lp ld} \par \textbf{ ll ln\_}& 
127\textbf{c} \par \textit{but not} \par \textbf{cp cd} \par \textbf{cl cn\_}& 
128\textbf{s} \par \textit{but not} \par \textbf{sd sd} \par \textbf{sl sn\_}& 
129\textbf{d} \par \textit{but not} \par \textbf{dp dd} \par \textbf{dl dn\_}& 
130\textbf{y} \par \textit{but not} \par \textbf{yp yd} \par \textbf{yl yn} \\
131\hline
132dummy \par argument& 
133\textbf{k} \par \textit{but not} \par \textbf{kf}& 
134\textbf{p} \par \textit{but not} \par \textbf{pp pf}& 
135\textbf{ld}& 
136\textbf{cd}& 
137\textbf{sd}& 
138\textbf{dd}& 
139\textbf{yd} \\
140\hline
141local \par variable& 
142\textbf{i}& 
143\textbf{z}& 
144\textbf{ll}& 
145\textbf{cl}& 
146\textbf{sl}& 
147\textbf{dl}& 
148\textbf{yl} \\
149\hline
150loop \par control& 
151\textbf{j} \par \textit{but not} \par \textbf{jp}& 
152& 
153& 
154&
155& 
156& 
157 \\
158\hline
159parameter& 
160\textbf{jp np\_}& 
161\textbf{pp}& 
162\textbf{lp}& 
163\textbf{cp}& 
164\textbf{sp}& 
165\textbf{dp}& 
166\textbf{yp} \\
167\hline
168
169namelist&
170\textbf{nn\_}& 
171\textbf{rn\_}& 
172\textbf{ln\_}& 
173\textbf{cn\_}& 
174\textbf{sn\_}& 
175\textbf{dn\_}& 
176\textbf{yn\_}
177\\
178\hline
179CPP \par macro& 
180\textbf{kf}& 
181\textbf{fs} \par & 
182& 
183&
184& 
185& 
186 \\
187\hline
188\end{tabular}
189\label{tab1}
190\end{center}
191\end{table}
192%--------------------------------------------------------------------------------------------------------------
193
194N.B.   Parameter here, in not only parameter in the \textsc{Fortran} acceptation, it is also used for code variables
195that are read in namelist and should never been modified during a simulation.
196It is the case, for example, for the size of a domain (jpi,jpj,jpk).
197
198\newpage
199% ================================================================
200% The program structure
201% ================================================================
202%\section{Program structure}
203%label{Apdx_D_structure}
204
205%To be done....
206\end{document}
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