Changes between Version 36 and Version 37 of doc/app/runtime_parameters

Timestamp:

Sep 13, 2010 3:03:39 PM (15 years ago)

Author:

weinreis

Comment:

--

doc/app/runtime_parameters

@@ -97 +97 @@
 Beside the standard quantities from the above list, the user can output any other quantities. These have to be defined and calculated within the user-defined code (see [[LINK]]). They can be selected for output with the user-parameter [[../userpar#data_output_user|data_output_user]] for which the same rules apply as for '''data_output'''. Output of the user defined quantities (time interval, averaging, selection of cross sections, etc.) is controlled with the parameters listed above and data are written to the same file(s) as the standard quantities.\\\\
 '''Output on parallel machines:'''\\\\
+By default, with parallel runs, processors output only data of their respective subdomains into seperate local files (file names are constructed by appending the four digit processor ID, e.g. <filename>_0000, <filename>_0001, etc.). After PALM has finished, the contents of these individual files are sampled into one final file using the program combine_plot_fields.x (to be started e.g. by a suitable OUTPUT command in the '''mrun''' configuration file).\\\\
+Alternatively, PALM is able to collect all grid points of a cross section on PE0 before output is done. In this case only one  output file ([[DATA_2D_XY_NETCDF]], etc.) is created and combine_plot_fields.x does not have to be called. In case of very large numbers of horizontal gridpoints, sufficient memory is required on PE0.  This method can be used by assigning [[data_output_2d_on_each_pe] = ''.F.''.\\\\
+3d volume data output is always handled seperately by each processor so that {{{combine_plot_fields.x}}} has to be called anyway after PALM has been finished.
 }}}
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