1 | % ================================================================ |
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2 | % Appendix D Ñ Coding Rules |
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3 | % ================================================================ |
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4 | \chapter{Coding Rules} |
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5 | \label{Apdx_D} |
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6 | \minitoc |
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7 | |
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8 | |
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9 | A "model life" is more than ten years. Its software, composed of a few |
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10 | hundred modules, is used by many people who are scientists or students |
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11 | and do not necessarily know every aspect of computing very well. |
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12 | Moreover, a well thought-out program is easier to read and understand, |
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13 | less difficult to modify, produces fewer bugs and is easier to maintain. |
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14 | Therefore, it is essential that the model development follows some rules : |
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15 | |
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16 | - well planned and designed |
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17 | |
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18 | - well written |
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19 | |
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20 | - well documented (both on- and off-line) |
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21 | |
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22 | - maintainable |
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23 | |
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24 | - easily portable |
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25 | |
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26 | - flexible. |
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27 | |
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28 | To satisfy part of these aims, \NEMO is written with a coding standard which |
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29 | is close to the ECMWF rules, named DOCTOR \citep{Gibson_TR86}. |
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30 | These rules present some advantages like : |
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31 | |
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32 | - to provide a well presented program |
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33 | |
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34 | - to use rules for variable names which allow recognition of their type |
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35 | (integer, real, parameter, local or shared variables, etc. ) so that debugging is |
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36 | facilitated. |
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37 | |
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38 | % ================================================================ |
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39 | % The program structure |
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40 | % ================================================================ |
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41 | \section{The program structure} |
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42 | \label{Apdx_D_structure} |
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43 | |
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44 | Each program begins with a set of headline comments containing : |
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45 | |
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46 | - the program title |
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47 | |
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48 | - the purpose of the routine |
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49 | |
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50 | - the method and algorithms used |
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51 | |
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52 | - the detail of input and output interfaces |
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53 | |
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54 | - the external routines and functions used (if they exist) |
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55 | |
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56 | - references (if they exist) |
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57 | |
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58 | - the author name(s), the date of creation and any updates. |
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59 | |
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60 | - Each program is split into several well separated sections and |
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61 | sub-sections with an underlined title and specific labelled statements. |
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62 | |
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63 | - A program has not more than 200 to 300 lines. |
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64 | |
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65 | % ================================================================ |
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66 | % Coding conventions |
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67 | % ================================================================ |
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68 | \section{Coding conventions} |
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69 | \label{Apdx_D_coding} |
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70 | |
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71 | - Use of the universal language \textsc{Fortran} 90, and try to avoid obsolescent |
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72 | features like statement functions, do not use GO TO and EQUIVALENCE statements. |
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73 | |
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74 | - A continuation line begins with the character {\$} indented by three spaces |
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75 | compared to the previous line. |
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76 | |
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77 | - Always use a three spaces indentation in DO loop, CASE, or IF-ELSEIF-ELSE-ENDIF |
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78 | statements. |
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79 | |
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80 | - use call to ctl\_stop routine instead of just a STOP. |
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81 | |
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82 | % ================================================================ |
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83 | % Naming Conventions |
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84 | % ================================================================ |
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85 | \section{Naming Conventions} |
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86 | \label{Apdx_D_naming} |
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87 | |
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88 | The purpose of the naming conventions is to use prefix letters to classify |
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89 | model variables. These conventions allow the variable type to be easily known |
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90 | and rapidly identified: |
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91 | |
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92 | %--------------------------------------------------TABLE-------------------------------------------------- |
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93 | \begin{table}[htbp] |
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94 | \begin{center} |
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95 | \begin{tabular}{|p{50pt}|p{50pt}|p{50pt}|p{50pt}|p{50pt}|p{50pt}|p{50pt}|} |
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96 | \hline Type \par / Status & integer& real& logical & character& double \par precision& complex \\ |
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97 | \hline |
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98 | public \par or \par module variable& |
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99 | \textbf{m n} \par \textit{but not } \par \textbf{nn\_}& |
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100 | \textbf{a b e f g h o} \textbf{q} \textit{to} \textbf{x} \par but not \par \textbf{fs rn\_}& |
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101 | \textbf{l} \par \textit{but not} \par \textbf{lp ld ll ln\_}& |
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102 | \textbf{c} \par \textit{but not} \par \textbf{cp cd cl cn\_}& |
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103 | \textbf{d} \par \textit{but not} \par \textbf{dp dd dl dn\_}& |
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104 | \textbf{y} \par \textit{but not} \par \textbf{yp yd yl} \\ |
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105 | \hline |
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106 | dummy \par argument& |
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107 | \textbf{k} \par \textit{but not} \par \textbf{kf}& |
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108 | \textbf{p} \par \textit{but not} \par \textbf{pp pf}& |
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109 | \textbf{ld}& |
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110 | \textbf{cd}& |
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111 | \textbf{dd}& |
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112 | \textbf{yd} \\ |
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113 | \hline |
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114 | local \par variable& |
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115 | \textbf{i}& |
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116 | \textbf{z}& |
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117 | \textbf{ll}& |
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118 | \textbf{cl}& |
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119 | \textbf{cd}& |
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120 | \textbf{yl} \\ |
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121 | \hline |
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122 | loop \par control& |
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123 | \textbf{j} \par \textit{but not } \par \textbf{jp}& |
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124 | & |
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125 | & |
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126 | & |
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127 | & |
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128 | \\ |
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129 | \hline |
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130 | parameter& |
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131 | \textbf{jp}& |
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132 | \textbf{pp}& |
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133 | \textbf{lp}& |
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134 | \textbf{cp}& |
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135 | \textbf{dp}& |
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136 | \textbf{yp} \\ |
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137 | \hline |
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138 | |
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139 | namelist& |
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140 | \textbf{nn\_}& |
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141 | \textbf{rn\_}& |
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142 | \textbf{ln\_}& |
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143 | \textbf{cn\_}& |
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144 | \textbf{dn\_}& |
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145 | \\ |
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146 | \hline |
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147 | CPP \par macro& |
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148 | \textbf{kf}& |
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149 | \textbf{sf} \par & |
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150 | & |
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151 | & |
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152 | & |
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153 | \\ |
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154 | \hline |
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155 | \end{tabular} |
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156 | \label{tab1} |
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157 | \end{center} |
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158 | \end{table} |
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159 | %-------------------------------------------------------------------------------------------------------------- |
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