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chap_misc.tex in NEMO/trunk/doc/latex/NEMO/subfiles – NEMO

source: NEMO/trunk/doc/latex/NEMO/subfiles/chap_misc.tex @ 14303

Last change on this file since 14303 was 14303, checked in by mathiot, 3 years ago

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1\documentclass[../main/NEMO_manual]{subfiles}
2
3\begin{document}
4
5\chapter{Miscellaneous Topics}
6\label{chap:MISC}
7
8\chaptertoc
9
10\paragraph{Changes record} ~\\
11
12{\footnotesize
13  \begin{tabularx}{\textwidth}{l||X|X}
14    Release & Author(s) & Modifications \\
15    \hline
16    {\em   X.X} & {\em Pierre Mathiot} & {update of the closed sea section}
17    {\em   4.0} & {\em ...} & {\em ...} \\
18    {\em   3.6} & {\em ...} & {\em ...} \\
19    {\em   3.4} & {\em ...} & {\em ...} \\
20    {\em <=3.4} & {\em ...} & {\em ...}
21  \end{tabularx}
22}
23
24\clearpage
25
26%% =================================================================================================
27\section{Representation of unresolved straits}
28\label{sec:MISC_strait}
29
30In climate modeling, it often occurs that a crucial connections between water masses is broken as
31the grid mesh is too coarse to resolve narrow straits.
32For example, coarse grid spacing typically closes off the Mediterranean from the Atlantic at
33the Strait of Gibraltar.
34In this case, it is important for climate models to include the effects of salty water entering the Atlantic from
35the Mediterranean.
36Likewise, it is important for the Mediterranean to replenish its supply of water from the Atlantic to
37balance the net evaporation occurring over the Mediterranean region.
38This problem occurs even in eddy permitting simulations.
39For example, in ORCA 1/4\deg\ several straits of the Indonesian archipelago (Ombai, Lombok...)
40are much narrow than even a single ocean grid-point.
41
42We describe briefly here the two methods that can be used in \NEMO\ to handle such
43improperly resolved straits. The methods consist of opening the strait while ensuring
44that the mass exchanges through the strait are not too large by either artificially
45reducing the cross-sectional area of the strait grid-cells or, locally increasing the
46lateral friction.
47
48%% =================================================================================================
49\subsection{Hand made geometry changes}
50\label{subsec:MISC_strait_hand}
51
52The first method involves reducing the scale factor in the cross-strait direction to a
53value in better agreement with the true mean width of the strait
54(\autoref{fig:MISC_strait_hand}).  This technique is sometime called "partially open face"
55or "partially closed cells".  The key issue here is only to reduce the faces of $T$-cell
56(\ie\ change the value of the horizontal scale factors at $u$- or $v$-point) but not the
57volume of the $T$-cell.  Indeed, reducing the volume of strait $T$-cell can easily produce
58a numerical instability at that grid point which would require a reduction of the model
59time step.  Thus to instigate a local change in the width of a Strait requires two steps:
60
61\begin{itemize}
62
63\item Add \texttt{e1e2u} and \texttt{e1e2v} arrays to the \np{cn_domcfg}{cn\_domcfg} file. These 2D
64arrays should contain the products of the unaltered values of: $\texttt{e1u}*\texttt{e2u}$
65and $\texttt{e1u}*\texttt{e2v}$ respectively. That is the original surface areas of $u$-
66and $v$- cells respectively.  These areas are usually defined by the corresponding product
67within the \NEMO\ code but the presence of \texttt{e1e2u} and \texttt{e1e2v} in the
68\np{cn_domcfg}{cn\_domcfg} file will suppress this calculation and use the supplied fields instead.
69If the model domain is provided by user-supplied code in \mdl{usrdef\_hgr}, then this
70routine should also return \texttt{e1e2u} and \texttt{e1e2v} and set the integer return
71argument \texttt{ie1e2u\_v} to a non-zero value. Values other than 0 for this argument
72will suppress the calculation of the areas.
73
74\item Change values of \texttt{e2u} or \texttt{e1v} (either in the \np{cn_domcfg}{cn\_domcfg} file or
75via code in  \mdl{usrdef\_hgr}), whereever a Strait reduction is required. The choice of
76whether to alter \texttt{e2u} or \texttt{e1v} depends. respectively,  on whether the
77Strait in question is North-South orientated (\eg\ Gibraltar) or East-West orientated (\eg
78Lombok).
79
80\end{itemize}
81
82The second method is to increase the viscous boundary layer thickness by a local increase
83of the fmask value at the coast. This method can also be effective in wider passages.  The
84concept is illustarted in the second part of  \autoref{fig:MISC_strait_hand} and changes
85to specific locations can be coded in \mdl{usrdef\_fmask}. The \forcode{usr_def_fmask}
86routine is always called after \texttt{fmask} has been defined according to the choice of
87lateral boundary condition as discussed in \autoref{sec:LBC_coast}. The default version of
88\mdl{usrdef\_fmask} contains settings specific to ORCA2 and ORCA1 configurations. These are
89meant as examples only; it is up to the user to verify settings and provide alternatives
90for their own configurations. The default \forcode{usr_def_fmask} makes no changes to
91\texttt{fmask} for any other configuration.
92
93\begin{figure}[!tbp]
94  \centering
95  \includegraphics[width=0.66\textwidth]{MISC_Gibraltar}
96  \includegraphics[width=0.66\textwidth]{MISC_Gibraltar2}
97  \caption[Two methods to defined the Gibraltar strait]{
98    Example of the Gibraltar strait defined in a 1\deg\ $\times$ 1\deg\ mesh.
99    \textit{Top}: using partially open cells.
100    The meridional scale factor at $v$-point is reduced on both sides of the strait to
101    account for the real width of the strait (about 20 km).
102    Note that the scale factors of the strait $T$-point remains unchanged.
103    \textit{Bottom}: using viscous boundary layers.
104    The four fmask parameters along the strait coastlines are set to a value larger than 4,
105    \ie\ "strong" no-slip case (see \autoref{fig:LBC_shlat}) creating a large viscous boundary layer
106    that allows a reduced transport through the strait.}
107  \label{fig:MISC_strait_hand}
108\end{figure}
109
110%% =================================================================================================
111\section[Closed seas (\textit{closea.F90})]{Closed seas (\protect\mdl{closea})}
112\label{sec:MISC_closea}
113
114\begin{listing}
115  \nlst{namclo}
116  \caption{\forcode{&namclo}}
117  \label{lst:namclo}
118\end{listing}
119
120Some configurations include inland seas and lakes as ocean
121points. This is particularly the case for configurations that are
122coupled to an atmosphere model where one might want to include inland
123seas and lakes as ocean model points in order to provide a better
124bottom boundary condition for the atmosphere. However there is no
125route for freshwater to run off from the lakes to the ocean and this
126can lead to large drifts in the sea surface height over the lakes. The
127closea module provides options to either fill in closed seas and lakes
128at run time, or to set the net surface freshwater flux for each lake
129to zero and put the residual flux into the ocean.
130
131The inland seas and lakes are defined using mask fields in the
132domain configuration file. Special treatment of the closed sea (redistribution of net freshwater or mask those), are defined in \autoref{lst:namclo} and
133can be trigger by \np{ln_closea}{ln\_closea}\forcode{=.true.} in namelist namcfg.
134
135The options available are the following:
136\begin{description}
137\item[\np{ln_maskcs}{ln\_maskcs}\forcode{ = .true.}] All the closed seas are masked using \textit{mask\_opensea} variable.
138\item[\np{ln_maskcs}{ln\_maskcs}\forcode{ = .false.}] The net surface flux over each inland sea or group of
139inland seas is set to zero each timestep and the residual flux is
140distributed over a target area.
141\end{description}
142
143When \np{ln_maskcs}{ln\_maskcs}\forcode{ = .false.},
1443 options are available for the redistribution (set up of these options is done in the tool DOMAINcfg):
145\begin{description}[font=$\bullet$ ]
146\item[ glo]: The residual flux is redistributed globally.
147\item[ emp]: The residual flux is redistributed as emp in a river outflow.
148\item[ rnf]: The residual flux is redistributed as rnf in a river outflow if negative. If there is a net evaporation, the residual flux is redistributed globally.
149\end{description}
150
151For each case, 2 masks are needed (\autoref{fig:MISC_closea_mask_example}):
152\begin{description}
153\item $\bullet$ one describing the 'sources' (ie the closed seas concerned by each options) called \textit{mask\_csglo}, \textit{mask\_csrnf}, \textit{mask\_csemp}.
154\item $\bullet$ one describing each group of inland seas (the Great Lakes for example) and the target area (river outflow or world ocean) for each group of inland seas (St Laurence for the Great Lakes for example) called
155\textit{mask\_csgrpglo}, \textit{mask\_csgrprnf}, \textit{mask\_csgrpemp}.
156\end{description}
157
158\begin{figure}[!tbp]
159  \centering
160  \includegraphics[width=0.66\textwidth]{MISC_closea_mask_example}
161  \caption[Mask fields for the \protect\mdl{closea} module]{
162    Example of mask fields for the \protect\mdl{closea} module.
163    \textit{Left}: a \textit{mask\_csrnf} field;
164    \textit{Right}: a \textit{mask\_csgrprnf} field.
165    In this example, if \protect\np{ln_closea}{ln\_closea} is set to \forcode{.true.},
166    the mean freshwater flux over each of the American Great Lakes will be set to zero,
167    and the total residual for all the lakes, if negative, will be put into
168    the St Laurence Seaway in the area shown.}
169  \label{fig:MISC_closea_mask_example}
170\end{figure}
171
172Closed sea not defined (because too small, issue in the bathymetry definition ...) are defined in \textit{mask\_csundef}.
173These points can be masked using the namelist option \np{ln_mask_csundef}{ln\_mask\_csundef}\forcode{= .true.} or used to correct the bathymetry input file.\\
174
175The masks needed for the closed sea can be created using the DOMAINcfg tool in the utils/tools/DOMAINcfg directory.
176See \autoref{sec:clocfg} for details on the usage of definition of the closed sea masks.
177
178%% =================================================================================================
179\section{Sub-domain functionality}
180\label{sec:MISC_zoom}
181
182%% =================================================================================================
183\subsection{Simple subsetting of input files via NetCDF attributes}
184
185The extended grids for use with the under-shelf ice cavities will result in redundant rows
186around Antarctica if the ice cavities are not active.  A simple mechanism for subsetting
187input files associated with the extended domains has been implemented to avoid the need to
188maintain different sets of input fields for use with or without active ice cavities.  This
189subsetting operates for the j-direction only and works by optionally looking for and using
190a global file attribute (named: \np{open_ocean_jstart}{open\_ocean\_jstart}) to determine the starting j-row
191for input.  The use of this option is best explained with an example:
192\medskip
193
194\noindent Consider an ORCA1
195configuration using the extended grid domain configuration file: \textit{eORCA1\_domcfg.nc}
196This file define a horizontal domain of 362x332.  The first row with
197open ocean wet points in the non-isf bathymetry for this set is row 42 (\fortran\ indexing)
198then the formally correct setting for \np{open_ocean_jstart}{open\_ocean\_jstart} is 41.  Using this value as
199the first row to be read will result in a 362x292 domain which is the same size as the
200original ORCA1 domain.  Thus the extended domain configuration file can be used with all
201the original input files for ORCA1 if the ice cavities are not active (\np{ln\_isfcav =
202.false.}).  Full instructions for achieving this are:
203
204\begin{itemize}
205\item Add the new attribute to any input files requiring a j-row offset, i.e:
206\begin{cmds}
207ncatted  -a open_ocean_jstart,global,a,d,41 eORCA1_domcfg.nc
208\end{cmds}
209
210\item Add the logical switch \np{ln_use_jattr}{ln\_use\_jattr} to \nam{cfg}{cfg} in the configuration
211namelist (if it is not already there) and set \forcode{.true.}
212\end{itemize}
213
214\noindent Note that with this option, the j-size of the global domain is (extended
215j-size minus \np{open_ocean_jstart}{open\_ocean\_jstart} + 1 ) and this must match the \texttt{jpjglo} value
216for the configuration. This means an alternative version of \textit{eORCA1\_domcfg.nc} must
217be created for when \np{ln_use_jattr}{ln\_use\_jattr} is active. The \texttt{ncap2} tool provides a
218convenient way of achieving this:
219
220\begin{cmds}
221ncap2 -s 'jpjglo=292' eORCA1_domcfg.nc nORCA1_domcfg.nc
222\end{cmds}
223
224The domain configuration file is unique in this respect since it also contains the value of \texttt{jpjglo}
225that is read and used by the model.
226Any other global, 2D and 3D, netcdf, input field can be prepared for use in a reduced domain by adding the
227\texttt{open\_ocean\_jstart} attribute to the file's global attributes.
228In particular this is true for any field that is read by \NEMO\ using the following optional argument to
229the appropriate call to \np{iom_get}{iom\_get}.
230
231\begin{forlines}
232lrowattr=ln_use_jattr
233\end{forlines}
234
235Currently, only the domain configuration variables make use of this optional argument so
236this facility is of little practical use except for tests where no other external input
237files are needed or you wish to use an extended domain configuration with inputs from
238earlier, non-extended configurations. Alternatively, it should be possible to exclude
239empty rows for extended domain, forced ocean runs using interpolation on the fly, by
240adding the optional argument to \texttt{iom\_get} calls for the weights and initial
241conditions. Experimenting with this remains an exercise for the user.
242
243%% =================================================================================================
244\section[Accuracy and reproducibility (\textit{lib\_fortran.F90})]{Accuracy and reproducibility (\protect\mdl{lib\_fortran})}
245\label{sec:MISC_fortran}
246
247%% =================================================================================================
248\subsection[Issues with intrinsinc SIGN function (\texttt{\textbf{key\_nosignedzero}})]{Issues with intrinsinc SIGN function (\protect\key{nosignedzero})}
249\label{subsec:MISC_sign}
250
251The SIGN(A, B) is the \fortran\ intrinsic function delivers the magnitude of A with the sign of B.
252For example, SIGN(-3.0,2.0) has the value 3.0.
253The problematic case is when the second argument is zero, because, on platforms that support IEEE arithmetic,
254zero is actually a signed number.
255There is a positive zero and a negative zero.
256
257In \fninety, the processor was required always to deliver a positive result for SIGN(A, B) if B was zero.
258Nevertheless, in \fninety, the processor is allowed to do the correct thing and deliver ABS(A) when
259B is a positive zero and -ABS(A) when B is a negative zero.
260This change in the specification becomes apparent only when B is of type real, and is zero,
261and the processor is capable of distinguishing between positive and negative zero,
262and B is negative real zero.
263Then SIGN delivers a negative result where, under \fninety\ rules, it used to return a positive result.
264This change may be especially sensitive for the ice model,
265so we overwrite the intrinsinc function with our own function simply performing :   \\
266\verb?   IF( B >= 0.e0 ) THEN   ;   SIGN(A,B) = ABS(A)  ?    \\
267\verb?   ELSE                   ;   SIGN(A,B) =-ABS(A)     ?  \\
268\verb?   ENDIF    ? \\
269This feature can be found in \mdl{lib\_fortran} module and is effective when \key{nosignedzero} is defined.
270We use a CPP key as the overwritting of a intrinsic function can present performance issues with
271some computers/compilers.
272
273%% =================================================================================================
274\subsection{MPP reproducibility}
275\label{subsec:MISC_glosum}
276
277The numerical reproducibility of simulations on distributed memory parallel computers is a critical issue.
278In particular, within \NEMO\ global summation of distributed arrays is most susceptible to rounding errors,
279and their propagation and accumulation cause uncertainty in final simulation reproducibility on
280different numbers of processors.
281To avoid so, based on \citet{he.ding_JS01} review of different technics,
282we use a so called self-compensated summation method.
283The idea is to estimate the roundoff error, store it in a buffer, and then add it back in the next addition.
284
285Suppose we need to calculate $b = a_1 + a_2 + a_3$.
286The following algorithm will allow to split the sum in two
287($sum_1 = a_{1} + a_{2}$ and $b = sum_2 = sum_1 + a_3$) with exactly the same rounding errors as
288the sum performed all at once.
289\begin{align*}
290   sum_1 \ \  &= a_1 + a_2 \\
291   error_1     &= a_2 + ( a_1 - sum_1 ) \\
292   sum_2 \ \  &= sum_1 + a_3 + error_1 \\
293   error_2     &= a_3 + error_1 + ( sum_1 - sum_2 ) \\
294   b \qquad \ &= sum_2 \\
295\end{align*}
296An example of this feature can be found in \mdl{lib\_fortran} module.
297It is systematicallt used in glob\_sum function (summation over the entire basin excluding duplicated rows and
298columns due to cyclic or north fold boundary condition as well as overlap MPP areas).
299The self-compensated summation method should be used in all summation in i- and/or j-direction.
300See \mdl{closea} module for an example.
301Note also that this implementation may be sensitive to the optimization level.
302
303%% =================================================================================================
304\subsection{MPP scalability}
305\label{subsec:MISC_mppsca}
306
307The default method of communicating values across the north-fold in distributed memory applications (\key{mpp\_mpi})
308uses a \textsc{MPI\_ALLGATHER} function to exchange values from each processing region in
309the northern row with every other processing region in the northern row.
310This enables a global width array containing the top 4 rows to be collated on every northern row processor and then
311folded with a simple algorithm.
312Although conceptually simple, this "All to All" communication will hamper performance scalability for
313large numbers of northern row processors.
314From version 3.4 onwards an alternative method is available which only performs direct "Peer to Peer" communications
315between each processor and its immediate "neighbours" across the fold line.
316This is achieved by using the default \textsc{MPI\_ALLGATHER} method during initialisation to
317help identify the "active" neighbours.
318Stored lists of these neighbours are then used in all subsequent north-fold exchanges to
319restrict exchanges to those between associated regions.
320The collated global width array for each region is thus only partially filled but is guaranteed to
321be set at all the locations actually required by each individual for the fold operation.
322This alternative method should give identical results to the default \textsc{ALLGATHER} method and
323is recommended for large values of \np{jpni}{jpni}.
324The new method is activated by setting \np{ln_nnogather}{ln\_nnogather} to be true (\nam{mpp}{mpp}).
325The reproducibility of results using the two methods should be confirmed for each new,
326non-reference configuration.
327
328%% =================================================================================================
329\section{Model optimisation, control print and benchmark}
330\label{sec:MISC_opt}
331
332\begin{listing}
333  \nlst{namctl}
334  \caption{\forcode{&namctl}}
335  \label{lst:namctl}
336\end{listing}
337
338Options are defined through the  \nam{ctl}{ctl} namelist variables.
339
340%% =================================================================================================
341\subsection{Vector optimisation}
342
343\key{vectopt\_loop} enables the internal loops to collapse.
344This is very a very efficient way to increase the length of vector calculations and thus
345to speed up the model on vector computers.
346
347% Add here also one word on NPROMA technique that has been found useless, since compiler have made significant progress during the last decade.
348
349% Add also one word on NEC specific optimisation (Novercheck option for example)
350
351%% =================================================================================================
352\subsection{Status and debugging information output}
353
354
355NEMO can produce a range of text information output either: in the main output
356file (ocean.output) written by the normal reporting processor (narea == 1) or various
357specialist output files (e.g. layout.dat, run.stat, tracer.stat etc.). Some, for example
358run.stat and tracer.stat, contain globally collected values for which a single file is
359sufficient. Others, however, contain information that could, potentially, be different
360for each processing region. For computational efficiency, the default volume of text
361information produced is reduced to just a few files from the narea=1 processor.
362
363When more information is required for monitoring or debugging purposes, the various
364forms of output can be selected via the \np{sn_cfctl}{sn\_cfctl} structure. As well as simple
365on-off switches this structure also allows selection of a range of processors for
366individual reporting (where appropriate) and a time-increment option to restrict
367globally collected values to specified time-step increments.
368
369Most options within the structure are influenced by the top-level switches shown here
370with their default settings:
371
372\begin{forlines}
373   sn_cfctl%l_allon  = .FALSE.    ! IF T activate all options. If F deactivate all unless l_config is T
374     sn_cfctl%l_config = .TRUE.     ! IF .true. then control which reports are written with the following
375\end{forlines}
376
377The first switch is a convenience option which can be used to switch on and off all
378sub-options. However, if it is false then switching off all sub-options is only done
379if \forcode{sn_cfctl%l\_config} is also false. Specifically, the logic is:
380
381\begin{forlines}
382  IF ( sn_cfctl%l_allon ) THEN
383    set all suboptions .TRUE.
384    and set procmin, procmax and procincr so that all regions are selected ([0,10000000,1], respectively)
385  ELSEIF ( sn_cfctl%l_config ) THEN
386    honour individual settings of the suboptions from the namelist
387  ELSE
388    set all suboptions .FALSE.
389  ENDIF
390\end{forlines}
391
392Details of the suboptions follow but first an explanation of the stand-alone option:
393\forcode{sn_cfctl%l_glochk}.  This option modifies the action of the early warning checks
394carried out in \texttt{stpctl.F90}. These checks detect probable numerical instabilites
395by searching for excessive sea surface heights or velocities and salinity values
396outside a sensible physical range. If breaches are detected then the default behaviour
397is to locate and report the local indices of the grid-point in breach. These indices
398are included in the error message that precedes the model shutdown. When true,
399\forcode{sn_cfctl%l_glochk} modifies this action by performing a global location of
400the various minimum and maximum values and the global indices are reported. This has
401some value in locating the most severe error in cases where the first detected error
402may not be the worst culprit.
403
404\subsubsection{Control print suboptions}
405
406The options that can be individually selected fall into three categories:
407
408\begin{enumerate} \item{Time step progress information} This category includes
409\texttt{run.stat} and \texttt{tracer.stat} files which record certain physical and
410passive tracer metrics (respectively). Typical contents of \texttt{run.stat} include
411global maximums of ssh, velocity; and global minimums and maximums of temperature
412and salinity.  A netCDF version of \texttt{run.stat} (\texttt{run.stat.nc}) is also
413produced with the same time-series data and this can easily be expanded to include
414extra monitoring information.  \texttt{tracer.stat} contains the volume-weighted
415average tracer value for each passive tracer. Collecting these metrics involves
416global communications and will impact on model efficiency so both these options are
417disabled by default by setting the respective options, \forcode{sn\_cfctl%runstat} and
418\forcode{sn\_cfctl%trcstat} to false. A compromise can be made by activating either or
419both of these options and setting the \forcode{sn\_cfctl%timincr} entry to an integer
420value greater than one. This increment determines the time-step frequency at which
421the global metrics are collected and reported.  This increment also applies to the
422time.step file which is otherwise updated every timestep.
423\item{One-time configuration information/progress logs}
424
425Some run-time configuration information and limited progress information is always
426produced by the first ocean process. This includes the \texttt{ocean.output} file
427which reports on all the namelist options read by the model and remains open to catch
428any warning or error messages generated during execution. A \texttt{layout.dat}
429file is also produced which details the MPI-decomposition used by the model. The
430suboptions: \forcode{sn\_cfctl%oceout} and \forcode{sn\_cfctl%layout} can be used
431to activate the creation of these files by all ocean processes.  For example,
432when \forcode{sn\_cfctl%oceout} is true all processors produce their own version of
433\texttt{ocean.output}.  All files, beyond the the normal reporting processor (narea == 1), are
434named with a \_XXXX extension to their name, where XXXX is a 4-digit area number (with
435leading zeros, if required). This is useful as a debugging aid since all processes can
436report their local conditions. Note though that these files are buffered on most UNIX
437systems so bug-hunting efforts using this facility should also utilise the \fortran:
438
439\forline|CALL FLUSH(numout)|
440
441statement after any additional write statements to ensure that file contents reflect
442the last model state. Associated with the \forcode{sn\_cfctl%oceout} option is the
443additional \forcode{sn\_cfctl%oasout} suboption. This does not activate its own output
444file but rather activates the writing of addition information regarding the OASIS
445configuration when coupling via oasis and the sbccpl routine. This information is
446written to any active \texttt{ocean.output} files.
447\item{Control sums of trends for debugging}
448
449NEMO includes an option for debugging reproducibility differences between
450a MPP and mono-processor runs.  This is somewhat dated and clearly only
451useful for this purpose when dealing with configurations that can be run
452on a single processor. The full details can be found in this report: \href{
453http://forge.ipsl.jussieu.fr/nemo/attachment/wiki/Documentation/prtctl_NEMO_doc_v2.pdf}{The
454control print option in NEMO} The switches to activate production of the control sums
455of trends for either the physics or passive tracers are the \forcode{sn\_cfctl%prtctl}
456and \forcode{sn\_cfctl%prttrc} suboptions, respectively. Although, perhaps, of limited use for its
457original intention, the ability to produce these control sums of trends in specific
458areas provides another tool for diagnosing model behaviour.  If only the output from a
459select few regions is required then additional options are available to activate options
460for only a simple subset of processing regions. These are: \forcode{sn\_cfctl%procmin},
461\forcode{sn\_cfctl%procmax} and \forcode{sn\_cfctl%procincr} which can be used to specify
462the minimum and maximum active areas and the increment. The default values are set
463such that all regions will be active. Note this subsetting can also be used to limit
464which additional \texttt{ocean.output} and \texttt{layout.dat} files are produced if
465those suboptions are active.
466
467\end{enumerate}
468
469\begin{forlines}
470   sn_cfctl%l_glochk  = .false. ! Range sanity checks are local (F) or global (T). Set T for debugging only
471   sn_cfctl%l_allon   = .false. ! IF T activate all options. If F deactivate all unless l_config is T
472   sn_cfctl%l_config  = .true.  ! IF .true. then control which reports are written with the following
473   sn_cfctl%l_runstat = .false. ! switches and which areas produce reports with the proc integer settings.
474   sn_cfctl%l_trcstat = .false. ! The default settings for the proc integers should ensure
475   sn_cfctl%l_oceout  = .false. ! that  all areas report.
476   sn_cfctl%l_layout  = .false. !
477   sn_cfctl%l_prtctl  = .false. !
478   sn_cfctl%l_prttrc  = .false. !
479   sn_cfctl%l_oasout  = .false. !
480   sn_cfctl%procmin   = 0       ! Minimum area number for reporting [default:0]
481   sn_cfctl%procmax   = 1000000 ! Maximum area number for reporting [default:1000000]
482   sn_cfctl%procincr  = 1       ! Increment for optional subsetting of areas [default:1]
483   sn_cfctl%ptimincr  = 1       ! Timestep increment for writing time step progress info
484\end{forlines}
485
486\subinc{\input{../../global/epilogue}}
487
488\end{document}
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