Changeset 10505
- Timestamp:
- 2019-01-11T15:32:07+01:00 (6 years ago)
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NEMO/branches/2019/dev_r10503_XIOS_RW_doc/doc/latex/NEMO/subfiles/chap_DIA.tex
r10442 r10505 115 115 Note that for smaller configurations, the rebuilding phase can be avoided, 116 116 even without a parallel-enabled NetCDF4 library, simply by employing only one dedicated I/O server. 117 118 \subsection{XIOS: Reading and writing restart file} 119 120 XIOS may be used to read single file restart produced by NEMO. Currently only the variables written to 121 file \textit{numror} can be handled by XIOS. To activate restart reading using XIOS \textit{ln\_xios\_read} 122 must be set to \textit{.true.}. 123 in \textit{namelist\_cfg}. This setting will be ignored when multiple restart files are present, and default NEMO 124 functionality will be used for reading. There is no need to change iodef.xml file to use XIOS to read 125 restart, all definitions are done within the NEMO code. For high resolution configuration, however, 126 there may be a need to add the following line in iodef.xml (xios context): 127 \textit{ 128 <variable id="recv\_field\_timeout" type="double">1800</variable>. 129 } 130 This variable sets timeout for reading. 131 132 If XIOS is to be used to read restart from file generated with an earlier NEMO version (3.6 for instance), 133 dimension \textit{z} defined in restart file must be renamed to \textit{nav\_lev}. 134 135 XIOS can also be used to write NEMO restart. A namelist parameter \textit{nn\_wxios} is used to determine the 136 type of restart NEMO will write. If it is set to 0, default NEMO functionality will be used - each 137 processor writes its own restart file; if it is set to 1 XIOS will write restart into a single file; 138 for \textit{nn\_wxios = 2} the restart will be written by XIOS into multiple files, one for each XIOS server. 139 Note, however, that \textbf{NEMO will not read restart generated by XIOS when \textit{nn\_wxios = 2}}. The restart will 140 have to be rebuild before continuing the run. This option aims to reduce number of restart files generated by NEMO only, 141 and may be useful when there is a need to change number of processors used to run simulation. 142 143 If an additional variable must be written to a restart file, the following steps are needed: 144 \begin{itemize} 145 \item 146 add variable name to a list of restart variables (in subroutine \textit{iom\_set\_rst\_vars}, iom.F90) and 147 define correct grid for the variable (grid\_N\_3D - 3D variable, grid\_N - 2D variable, grid\_vector - 148 1D variable, grid\_scalar - scalar), 149 \item 150 add variable to the list of fields written by restart. This can be done either in subroutine 151 \textit{iom\_set\_rstw\_core} (iom.F90) or by calling \textit{iom\_set\_rstw\_active} (iom.F90) with the name of a variable 152 as an argument. This convention follows approach for writing restart using iom, where variables are 153 written either by \textit{rst\_write} or by calling \textit{iom\_rstput} from individual routines. 154 \end{itemize} 155 156 157 An older versions of XIOS do not support reading functionality. It's recommended to use at least XIOS2@1451. 158 117 159 118 160 \subsection{XIOS: XML Inputs-Outputs Server}
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