- Timestamp:
- 2011-03-16T15:22:28+01:00 (13 years ago)
- Location:
- trunk/DOC
- Files:
-
- 2 edited
Legend:
- Unmodified
- Added
- Removed
-
trunk/DOC/NEMO_coding.conv.tex
r2691 r2697 31 31 32 32 \title{ 33 \includegraphics[width=0.3\textwidth]{./TexFiles/F Igures/NEMO_logo_Black.pdf} \\33 \includegraphics[width=0.3\textwidth]{./TexFiles/Figures/NEMO_logo_Black.pdf} \\ 34 34 \vspace{1.0cm} 35 35 \rule{345pt}{1.5pt} \\ … … 54 54 This document describes conventions\index{conventions} used in NEMO coding and suggested for its development. The objectives are to offer a guide to all readers of the NEMO code, and to facilitate the work of all the developers, including the validation of their developments, and eventually the implementation of these developments within the NEMO platform. \\ 55 55 A first approach of these rules can be found in the code in $NEMO/OPA\_SRC/module\_example$ where all the basics coding conventions are illustrated. More details can be found below.\\ 56 This work is based on the coding conventions i s use for the Community Climate System Model\footnote { http://www.cesm.ucar.edu/working\_groups/Software/dev\_guide/dev\_guide/node7.html }57 the previous version of this document ( ÒFORTRAN coding standard in the OPA SystemÓ) and the expertise of the NEMO System Team which can be contacted for further information ($nemo\_st@locean-ipsl.upmc.fr$)56 This work is based on the coding conventions in use for the Community Climate System Model, \footnote { http://www.cesm.ucar.edu/working\_groups/Software/dev\_guide/dev\_guide/node7.html } 57 the previous version of this document (``FORTRAN coding standard in the OPA System'') and the expertise of the NEMO System Team which can be contacted for further information ($nemo\_st@locean-ipsl.upmc.fr$) 58 58 After a general overview below, this document will describe : 59 59 \begin{itemize} … … 65 65 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 66 66 \section{Overview and general conventions} 67 NEMO has different component: ocean dynamics ($OPA\_SRC$), sea-ice ($LIM\_SRC$), ocean biogeochemistry\- ($TOP\_SRC$), linear-tangent and adjoint of the dynamics ($TAM$)É each of them corresponding to a directory.67 NEMO has several different components: ocean dynamics ($OPA\_SRC$), sea-ice ($LIM\_SRC$), ocean biogeochemistry\- ($TOP\_SRC$), linear-tangent and adjoint of the dynamics ($TAM$)É each of them corresponding to a directory. 68 68 In each directory, one will find some FORTRAN files and/or subdirectories, one per functionality of the code: $BDY$ (boundaries), $DIA$ (diagnostics), $DOM$ (domain), $DYN$ (dynamics), $LDF$ (lateral diffusion), etc...\\ 69 69 All name are chosen to be as self-explanatory as possible, in English, all prefixes are 3 digits.\\ 70 70 English is used for all variables names, comments, and documentation. \\ 71 Physical units are MKS. Only exception for the temperature, which is expressed in degreeCelsius, except in bulk formulae and part of LIM sea-ice model where it is in Kelvin. See $DOM/phycst.F90$ files for conversions.71 Physical units are MKS. The only exception to this is the temperature, which is expressed in degrees Celsius, except in bulk formulae and part of LIM sea-ice model where it is in Kelvin. See $DOM/phycst.F90$ files for conversions. 72 72 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 73 73 \section{Architecture} 74 Within each directory, organisation of files is driven by ÒorthogonalityÓ\index{orthogonality}, i.e. one functionality of the code is inten ted to be in one and only one directory, and one module and all its related routines are in one file.74 Within each directory, organisation of files is driven by ÒorthogonalityÓ\index{orthogonality}, i.e. one functionality of the code is intended to be in one and only one directory, and one module and all its related routines are in one file. 75 75 The functional modules\index{module} are: 76 76 \begin{itemize} … … 90 90 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 91 91 \subsection{Argument list format} 92 Routine sargument lists will contain a maximum 5 variables\index{variable} per line, whilst continuation lines can be used.92 Routine argument lists will contain a maximum 5 variables\index{variable} per line, whilst continuation lines can be used. 93 93 This applies both to the calling routine and the dummy argument list in the routine being called. The purpose is to simplify matching up the arguments between caller and callee. 94 94 … … 112 112 & - twodarray2(:,2:len2 ) ) 113 113 \end{verbatim} 114 For long, complicated loops, explicitly indexed loops should be preferred. In general when using this syntax, the order of the loops indices should reflect the following scheme : (best usage of data locality):114 For long, complicated loops, explicitly indexed loops should be preferred. In general when using this syntax, the order of the loops indices should reflect the following scheme (for best usage of data locality): 115 115 \begin{verbatim} 116 116 DO jk = 1, jpk … … 124 124 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 125 125 \subsection{Case} 126 All FORTRAN keywords are in capital : \begin {verbatim} DIMENSION, WRITE, DO ÉEND DO, NAMELIST \end{verbatim}126 All FORTRAN keywords are in capital : \begin {verbatim} DIMENSION, WRITE, DO, END DO, NAMELIST \end{verbatim} 127 127 All other parts of the NEMO code will be written in lower case. 128 128 … … 132 132 The full documentation and detailed explanations are to be added in the reference manual (TeX files, aside from the code itself). \\ 133 133 In the code, the comments should explain variable content and describe each computational step.\\ 134 Comments in the header start with Ò!!Ó. For more details on the content of the headers, see ÒContent rules/HeadersÓ in this document.\\135 Comments in the code start with "!".\\134 Comments in the header start with ``!!''. For more details on the content of the headers, see ÒContent rules/HeadersÓ in this document.\\ 135 Comments in the code start with ``!''.\\ 136 136 All comments are indented (3, 6, or 9 É blank spaces).\\ 137 137 Short comments may be included on the same line as executable code, and an additional line can be used with proper alignment. For example: … … 163 163 & * fse3uw_b(ji,jj,jk) ) 164 164 \end{verbatim} 165 Code lines, which are continuation lines of assignment statements, must begin to the right of the column of the assignment operator. Due to the possibility of automatic indentation in some editor (emacs for example), use a Ô\&Õas first character of the continuing lines to maintain the alignment.165 Code lines, which are continuation lines of assignment statements, must begin to the right of the column of the assignment operator. Due to the possibility of automatic indentation in some editor (emacs for example), use a ``\&'' as first character of the continuing lines to maintain the alignment. 166 166 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 167 167 \subsection{Declaration of arguments and local variables} … … 173 173 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 174 174 \subsection{F90 Standard} 175 NEMO software adheres to the FORTRAN 95 language standard and does not rely on any specific language or vendor extension .175 NEMO software adheres to the FORTRAN 95 language standard and does not rely on any specific language or vendor extensions. 176 176 177 177 178 178 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 179 179 \subsection{Free-Form Source} 180 Free-form source will be used. The F90/95 standard allows up to 132 characters, but a self-imposed limit of 80 should enhance readability, or print source files with two columns per page. Multi-line comments that extend to column 100 would be unacceptable.180 Free-form source will be used. The F90/95 standard allows lines of up to 132 characters, but a self-imposed limit of 80 should enhance readability, or print source files with two columns per page. Multi-line comments that extend to column 100 are unacceptable. 181 181 182 182 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% … … 195 195 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 196 196 \subsection{Loops} 197 Loops, if explicit, should be structured with the do-end do construct as opposed to numbered loops. Nevertheless non-num ber label can be used for a big iterative loop of recursive algorithm. In case oflong loop, a self-descriptive label can be used (i.e. not just a number).197 Loops, if explicit, should be structured with the do-end do construct as opposed to numbered loops. Nevertheless non-numeric labels can be used for a big iterative loop of a recursive algorithm. In the case of a long loop, a self-descriptive label can be used (i.e. not just a number). 198 198 199 199 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 200 200 \subsection{Naming Conventions: files} 201 A file containing a module will have the same name as the inside module. 201 A file containing a module will have the same name as the module it contains (because dependency rules used by "make" programs are based on file names). 202 \footnote{For example, if routine A "USE"s module B, then "make" must be told of the dependency relation which requires B to be compiled before A. If one can assume that module B resides in file B.o, building a tool to generate this dependency rule (e.g. A.o: B.o) is quite simple. Put another way, it is difficult (to say nothing of CPU-intensive) to search an entire source tree to find the file in which module B resides for each routine or module which "USE"s B.} 202 203 203 204 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 204 205 \subsection{Naming Conventions: modules} 205 Use meaningful English name and the Ò3 lettersÓ naming convention: first 3 metters for the code section, and last 3 to describe the module. For example, zdftke, where ÒzdfÓ stands for vertical diffusion, and ÒtkeÓ for turbulent kinetic energy. 206 Modules must be called with the same name as the file in which they reside, because dependency rules used by "make" programs are based on file names 207 \footnote{For example, if routine A "USE"s module B, then "make" must be told of the dependency relation which requires B to be compiled before A. If one can assume that module B resides in file B.o, building a tool to generate this dependency rule (e.g. A.o: B.o) is quite simple. Put another way, it is difficult (to say nothing of CPU-intensive) to search an entire source tree to find the file in which module B resides for each routine or module which "USE"s B.} 208 . 206 Use a meaningful English name and the ``3 letters'' naming convention: first 3 letters for the code section, and last 3 to describe the module. For example, zdftke, where ``zdf'' stands for vertical diffusion, and ``tke'' for turbulent kinetic energy. 209 207 \\ 210 208 Note that by implication multiple modules are not allowed in a single file. 211 The use of common blocks is deprecated in Fortran 90 and their use in NEMO is strongly discouraged. Modules are a better way to declare static data. Among the advantages of modules is the ability to freely mix data of various types, and to limit access to contained variables through use of the ONLY and PRIVATE attributes.209 The use of common blocks is deprecated in Fortran 90 and their use in NEMO is strongly discouraged. Modules are a better way to declare static data. Among the advantages of modules is the ability to freely mix data of various types, and to limit access to contained variables through the use of the ONLY and PRIVATE attributes. 212 210 213 211 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 214 212 \subsection{Naming Conventions: variables} 215 All variable should be named as explicit as possible in English. The naming convention concerns prefix letters of these name, in order to identify the variable type and status.\\213 All variable should be named as explicitly as possible in English. The naming convention concerns prefix letters of these name, in order to identify the variable type and status.\\ 216 214 Never use a FORTRAN keyword as a routine or variable name. \\ 217 T able below lists the stating letter(s) to be used for variable naming, depending on their type and status:215 The table below lists the starting letter(s) to be used for variable naming, depending on their type and status: 218 216 %--------------------------------------------------TABLE-------------------------------------------------- 219 217 \begin{table}[htbp] … … 293 291 Where the use of a language pre-processor is required, it will be the C pre-processor (cpp).\\ 294 292 The cpp key is the main feature used, allowing to ignore some useless parts of the code at compilation step. \\ 295 The advantage is to reduce the memory use; the drawback is that compilation of this part of the code isn Õt checked. \\296 The cpp key feature should only be used for a few limited options, if i sreduces the memory usage. In all cases, a logical variable and a FORTRAN $IF$ should be preferred.293 The advantage is to reduce the memory use; the drawback is that compilation of this part of the code isn't checked. \\ 294 The cpp key feature should only be used for a few limited options, if it reduces the memory usage. In all cases, a logical variable and a FORTRAN $IF$ should be preferred. 297 295 When using a cpp key $key\_optionname$, a corresponding logical variable $lk\_optionname$ should be declared to allow FORTRAN $IF$ tests in the code and a FORTRAN module with the same name (i.e. $optionname.F90$) should 298 to be defined. This module is the only place where a \#if definedcommand appears, selecting either the whole FORTRAN code or a dummy module. For example, the TKE vertical physics, the module name is $zdftke.F90$, the CPP key is $key\_zdftke$ and the associated logical is $lk\_zdftke$.296 be defined. This module is the only place where a ``\#if defined'' command appears, selecting either the whole FORTRAN code or a dummy module. For example, the TKE vertical physics, the module name is $zdftke.F90$, the CPP key is $key\_zdftke$ and the associated logical is $lk\_zdftke$. 299 297 300 298 The following syntax: … … 316 314 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 317 315 \subsection{Configurations} 318 The configuration defines the domain and the grid on which NEMO is running. It may be useful lto associate a cpp key and some variables to a given configuration, although the part of the code changed under each of those keys should be minimized. As an example, the "ORCA2" configuration (global ocean, 2 degrees grid size) is associated with the cpp key $key\_orca2$ for which316 The configuration defines the domain and the grid on which NEMO is running. It may be useful to associate a cpp key and some variables to a given configuration, although the part of the code changed under each of those keys should be minimized. As an example, the "ORCA2" configuration (global ocean, 2 degrees grid size) is associated with the cpp key $key\_orca2$ for which 319 317 \begin{verbatim} 320 318 cp_cfg = "orca" … … 332 330 \begin{itemize} 333 331 \item Usage of the DIMENSION statement or attribute is required in declaration statements 334 \item Attribute SAVE is banned. This simplifies the use of AGRIF software. Since all the subroutine are embedded into a module, the variables which value have to be preserved between two calls can be declared in the module interface. 335 The Ò::Ó notation is quite useful to show that this program unit declaration part is written in standard FORTRAN syntax, even if there are no attributes to clarify the declaration section. Always use the notation <blank>:<three blanks> to improve readability. 332 \item The ``::'' notation is quite useful to show that this program unit declaration part is written in standard FORTRAN syntax, even if there are no attributes to clarify the declaration section. Always use the notation $<$blank$>$::$<$three blanks$>$ to improve readability. 336 333 \item Declare the length of a character variable using the CHARACTER (len=xxx) syntax 337 \footnote { The len specifier is important because it is possible to have several kinds for characters (e.g. Unicode using two bytes per character, or there might be a different kind for Japanese e.g. .NEC). }334 \footnote { The len specifier is important because it is possible to have several kinds for characters (e.g. Unicode using two bytes per character, or there might be a different kind for Japanese e.g. NEC). } 338 335 339 336 \item For all global data (in contrast to module data, that is all data that can be access by other module) must be accompanied with a comment field on the same line. 340 \footnote {This allows a easy research of where and how a variable is declared using the unix command: Ògrep var *90 |grep !:Ó. }337 \footnote {This allows a easy research of where and how a variable is declared using the unix command: ``grep var *90 |grep !:''. } 341 338 \\ 342 339 For example: … … 349 346 All subroutines and functions will include an IMPLICIT NONE statement. 350 347 Thus all variables must be explicitly typed. It also allows the compiler to detect typographical errors in variable names. 351 For modules, one IMPLICIT NONE statement in the modules definition section is needed. 348 For modules, one IMPLICIT NONE statement in the modules definition section is needed. This also removes the need to have IMPLICIT NONE statements in any routines that are CONTAIN'd in the module. 352 349 Improper data initialisation is another common source of errors. 353 350 \footnote{A variable could contain an initial value you did not expect. This can happen for several reasons, e.g. the variable has never been assigned a value, its value is outdated, memory has been allocated for a pointer but you have forgotten to initialise the variable pointed to.} … … 364 361 \subsection{Headers} 365 362 Prologues are not used in NEMO for now, although it may become an interesting tool in combination with ProTeX auto documentation script in the future. 366 Rules to code the headers and layout of a module or a routine are illustrated in the example module available with the code : $NEMO/OPA\_SRC/module\_example$363 Rules to code the headers and layout of a module or a routine are illustrated in the example module available with the code : {\it NEMO/OPA\_SRC/module\_example} 367 364 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 368 365 \subsection{Interface blocks} … … 385 382 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 386 383 \subsection{Precision} 387 Parameterizations should not rely on vendor-supplied flags to supply a default floating point precision or integer size. The f95$ KIND$ feature should be used instead. In order to improve portability between 32 and 64 bit platforms, it is necessary to make use of kinds by using a specific module ($OPA\_SRC/par\_kind.F90$) declaring the "kind definitions" to obtain the required numerical precision and range as well as size of INTEGER. It should be noted that constants need to have attached a \_kindvalueto have the according size. \\388 Thus wpbeing the "working precision" as declared in $OPA\_SRC/par\_kind.F90$, declaring real array $zpc$ will take the form:384 Parameterizations should not rely on vendor-supplied flags to supply a default floating point precision or integer size. The F95$ KIND$ feature should be used instead. In order to improve portability between 32 and 64 bit platforms, it is necessary to make use of kinds by using a specific module ($OPA\_SRC/par\_kind.F90$) declaring the "kind definitions" to obtain the required numerical precision and range as well as the size of INTEGER. It should be noted that numerical constants need to have a suffix of \_$kindvalue$ to have the according size. \\ 385 Thus $wp$ being the "working precision" as declared in $OPA\_SRC/par\_kind.F90$, declaring real array $zpc$ will take the form: 389 386 \begin{verbatim} 390 387 REAL(wp), DIMENSION(jpi,jpj,jpk) :: zpc ! power consumption 391 388 \end{verbatim} 392 389 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 393 390 \subsection{Structures} … … 404 401 405 402 TYPE(PTRACER) , DIMENSION(jptra) :: tracer 406 403 \end{verbatim} 407 404 408 405 Missing rule on structure name?? … … 412 409 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 413 410 \subsection{Bounds checking} 414 NEMO is able to run when an array bounds checking option is enabled . \\411 NEMO is able to run when an array bounds checking option is enabled (provided the cpp key $key\_vectopt\_loop$ is not defined). \\ 415 412 Thus, constructs of the following form are disallowed: 416 413 \begin{verbatim} 417 414 REAL(wp) :: arr(1) 418 415 \end{verbatim} 419 416 where "arr" is an input argument into which the user wishes to index beyond 1. Use of the (*) construct in array dimensioning is forbidden also because it effectively disables array bounds checking. 420 417 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% … … 429 426 \subsection{Memory management} 430 427 431 The main action is to identify and declare which arrays are PUBLIC and which are PRIVATE.\\ 432 Dynamic memory allocation should be avoided, unless necessary. Indeed, it may be desirable in some occasions. However, this type of memory allocation can reduce performance on some machines, and some debuggers may get confused when trying to diagnose the contents of such variables. \\ 433 434 The preferable mechanism for dynamic memory allocation is automatic arrays, as opposed to $ALLOCATABLE$ or $POINTER$ arrays for which memory must be explicitly allocated and de-allocated. 435 \footnote {$POINTER$ and $ALLOCATE$ are widely used in AGRIF, and in the routine reading input files.} 436 An example of an automatic array is: 428 The main action is to identify and declare which arrays are PUBLIC and 429 which are PRIVATE.\\ As of version 3.3.1 of NEMO, the use of static 430 arrays (size fixed at compile time) has been deprecated. All module 431 arrays are now declared ALLOCATABLE and allocated in either the 432 $<$module\_name$>$\_alloc() or $<$module\_name$>$\_init() 433 routines. The success or otherwise of each ALLOCATE must be checked 434 using the $Stat=<integer\ variable>$ optional argument.\\ 435 436 In addition to arrays contained within modules, many routines in NEMO 437 require local, ``workspace'' arrays to hold the intermediate results 438 of calculations. In previous versions of NEMO, these arrays were 439 declared in such a way as to be automatically allocated on the stack 440 when the routine was called. An example of an automatic array is: 437 441 \begin{verbatim} 438 442 SUBROUTINE sub(n) … … 441 445 END SUBROUTINE sub 442 446 \end{verbatim} 443 444 Whereas the same example with $ALLOCATE$ is: 445 \begin{verbatim} 446 SUBROUTINE sub(n) 447 REAL, ALLOCATABLE :: a(:) 448 ALLOCATE(a(n)) 447 The downside of this approach is that the program will crash if it 448 runs out of stack space and the reason for the crash might not be 449 obvious to the user. 450 451 Therefore, as of version 3.3.1, the use of automatic arrays is 452 deprecated. Instead, a new module, ``wrk\_nemo,'' has been introduced 453 which contains 1-,2-,3- and 4-dimensional workspace arrays for use in 454 subroutines. These workspace arrays should be used in preference to 455 declaring new, local (allocatable) arrays whenever possible. The only 456 exceptions to this are when workspace arrays with lower bounds other 457 than 1 and/or with extent(s) greater than those in the {\it wrk\_nemo} 458 module are required.\\ 459 460 The 2D, 3D and 4D workspace arrays in {\it wrk\_nemo} have extents 461 $jpi$, $jpj$, $jpk$ and $jpts$ ($x$, $y$, $z$ and tracers) in the first, 462 second, third and fourth dimensions, respectively. The 1D arrays are 463 allocated with extent MAX($jpi\times jpj, jpk\times jpj, jpi\times 464 jpk$).\\ 465 466 The REAL (KIND=$wp$) workspace arrays in {\it wrk\_nemo} are named 467 e.g. $wrk\_1d\_1$, $wrk\_4d\_2$ etc. and should be accessed by USE'ing 468 the {\it wrk\_nemo} module. Since these arrays are available to any 469 routine, some care must be taken that a given workspace array is not 470 already being used somewhere up the call stack. To help with this, 471 {\it wrk\_nemo} also contains some utility routines; {\it 472 wrk\_in\_use()} and {\it wrk\_not\_released()}. The former first 473 checks that the requested arrays are not already in use and then sets 474 internal flags to show that they are now in use. The {\it 475 wrk\_not\_released()} routine un-sets those internal flags. A 476 subroutine using this functionality for two, 3D workspace arrays named 477 $zwrk1$ and $zwrk2$ will look something like: 478 \begin{verbatim} 479 SUBROUTINE sub() 480 USE wrk_nemo, ONLY: wrk_in_use, wrk_not_released 481 USE wrk_nemo, ONLY: zwrk1 => wrk_3d_5, zwrk2 => wrk_3d_6 482 ! 483 IF(wrk_in_use(3, 5,6)THEN 484 CALL ctl_stop('sub: requested workspace arrays unavailable.') 485 RETURN 486 END IF 449 487 ... 450 DEALLOCATE(a) ... 488 ... 489 IF(wrk_not_released(3, 5,6)THEN 490 CALL ctl_stop('sub: failed to release workspace arrays.') 491 END IF 492 ! 451 493 END SUBROUTINE sub 452 494 \end{verbatim} 495 The first argument to each of the utility routines is the 496 dimensionality of the required workspace (1--4). Following this there 497 must be one or more integers identifying which workspaces are to be 498 used/released. 499 Note that, in the interests of keeping the code as simple as possible, 500 there is no use of POINTERs etc. in the {\it wrk\_nemo} 501 module. Therefore it is the responsibility of the developer to ensure 502 that the arguments to {\it wrk\_in\_use()} and {\it 503 wrk\_not\_released()} match the workspace arrays actually being used 504 by the subroutine.\\ 505 506 If a workspace array is required that has extent(s) less than those of 507 the arrays in the {\it wrk\_nemo} module then the advantages of 508 implicit loops and bounds checking may be retained by defining a 509 pointer to a sub-array as follows: 510 \begin{verbatim} 511 SUBROUTINE sub() 512 USE wrk_nemo, ONLY: wrk_in_use, wrk_not_released 513 USE wrk_nemo, ONLY: wrk_3d_5 514 ! 515 REAL(wp), DIMENSION(:,:,:), POINTER :: zwrk1 516 ! 517 IF(wrk_in_use(3, 5)THEN 518 CALL ctl_stop('sub: requested workspace arrays unavailable.') 519 RETURN 520 END IF 521 ! 522 zwrk1 => wrk_3d_5(1:10,1:10,1:10) 523 ... 524 END SUBROUTINE sub 525 \end{verbatim} 526 Here, instead of ``use associating'' the variable $zwrk1$ with the 527 array $wrk\_3d\_5$ (as in the first example), it is explicitly 528 declared as a pointer to a 3D array. It is then associated with a 529 sub-array of $wrk\_3d\_5$ once the call to {\it wrk\_in\_use()} has 530 completed successfully. Note that in F95 (to which NEMO conforms) it 531 is not possible for either the upper or lower array bounds of the 532 pointer object to differ from those of the target array.\\ 533 534 In addition to the REAL (KIND=$wp$) workspace arrays, {\it wrk\_nemo} 535 also contains 2D integer arrays and 2D REAL arrays with extent ($jpi$, 536 $jpk$), {\it i.e.} $xz$. The utility routines for the integer 537 workspaces are {\it iwrk\_in\_use()} and {\it iwrk\_not\_released()} 538 while those for the $xz$ workspaces are {\it wrk\_in\_use\_xz()} 539 and {\it wrk\_not\_released\_xz()}. 540 541 Should a call to one of the {\it wrk\_in\_use()} family of utilities 542 fail, an error message is printed along with a table showing which of 543 the workspace arrays are currently in use. This should enable the 544 developer to choose alternatives for use in the subroutine being 545 worked on.\\ 546 547 When compiling NEMO for production runs, the calls to {\it 548 wrk\_in\_use()}/{\it wrk\_not\_released()} can be reduced to stubs 549 that just return $.$FALSE$.$ by setting the cpp key 550 {\it key\_no\_workspace\_check}. These stubs may then be inlined (and 551 thus effectively removed altogether) by setting appropriate compiler 552 flags (e.g. ``-finline'' for the Intel compiler or ``-Q'' for the IBM 553 compiler). 453 554 454 555 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% … … 464 565 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 465 566 \subsection{Package attribute: $PRIVATE, PUBLIC, USE, ONLY$} 466 Module svariables and routines should be encapsulated by using the PRIVATE attribute. What shall be used outside the module can be declared PUBLIC instead. Use USE with the ONLY attribute to specify which of the variables, type definitions etc. defined in a module are to be made available to the using routine.567 Module variables and routines should be encapsulated by using the PRIVATE attribute. What shall be used outside the module can be declared PUBLIC instead. Use USE with the ONLY attribute to specify which of the variables, type definitions etc. defined in a module are to be made available to the using routine. 467 568 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 468 569 \subsection {Parallelism: using MPI} 469 NEMO is written in order to be able to run on one processor, or on one or more using MPI (i.e. activating the cpp key $key _mpp\_mpi$, and defining the number of subdomains in latitude and longitude. The domain decomposition divides the global domain in cubes (see NEMO reference manual). Whilst coding a new development, the MPI compatibility has to be taken in account (see $lib\_mpp.F90$) and should be tested.570 NEMO is written in order to be able to run on one processor, or on one or more using MPI (i.e. activating the cpp key $key\_mpp\_mpi$. The domain decomposition divides the global domain in cubes (see NEMO reference manual). Whilst coding a new development, the MPI compatibility has to be taken in account (see $LBC/lib\_mpp.F90$) and should be tested. By default, the $x$-$z$ part of the decomposition is chosen to be as square as possible. However, this may be overriden by specifying the number of subdomains in latitude and longitude in the nammpp section of the namelist file. 470 571 471 572 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 472 573 \section{Features to be avoided} 473 574 474 The code must follow the current standards of FORTRAN and ANSI C. In particular, the code should not produce any WARNING at compiling phase, so that user can be easily alerted of potential bugs when some appear in their new developments. ).575 The code must follow the current standards of FORTRAN and ANSI C. In particular, the code should not produce any WARNING at compiling phase, so that users can be easily alerted of potential bugs when some appear in their new developments. ). 475 576 Below is a list of features to avoid: 476 577 \begin{itemize}
Note: See TracChangeset
for help on using the changeset viewer.