Running SUNTANS

Before running SUNTANS, you must have a valid triangulation and a valid parameter file suntans.dat. For details on the triangulation, see Section 3, and for details on the suntans.dat parameter file, see Section 7. If you have a valid grid and parameter file in the same directory as the sun executable, SUNTANS can be executed as a single processor job by running the main executable sun with

mpirun sun -t -g -s

Running with the input and output data files in the same directory as the source and executable is in general not a good idea because SUNTANS creates many input and output files that will clutter up the local directory. It is best to create a new directory and specify that directory as the working data directory on the command line and place the grid and parameter files in that directory. For example, if the input files are in the local data directory, then SUNTANS would be run with

mpirun sun -t -g -s --datadir=./data

To run SUNTANS on multiple processors, use the -np flag with mpirun. For example, to run SUNTANS on 64 processors, use

mpirun -np 64 sun -t -g -s --datadir=./data

The following is a list of flags that determine the behavior of the sun executable upon running:

• -t Create a triangulation from a planar straight line graph. For details see Section 3.
• -g Partition the triangulation among the given number of processors and compute grid geometry and cell and processor connectivity. For details see Section 3.
• -s Run the SUNTANS solver.
• -v[vvv] Output information about the progress of the run. The more vs, the more verbose the output (maximum 4).
• -w Print out warnings that may lead to crashes or erroneous results to the screen (independent of -v).
• -r Restart SUNTANS from a previous run. For details see Section 5.

A typical SUNTANS run with, for example, 4 processors, will proceed as follows:

1. Place the parameter file suntans.dat and planar straight line graph file in a directory, say the data directory.
2. Create the triangulation and grid information with

   mpirun -np 4 sun -t -g --datadir=./data
   

   This stores the grid information in files (see Section 3) for later reading later. Since this process may take some time it is a good idea to run this once for large grids and read in the grid data from a file.
3. Read the grid data from the files and run the solver and output information about the run with

   mpirun -np 4 sun -s -vv --datadir=./data
   

4. Once this run is finished it is possible to restart the run (for details see Section 5) with the data in data using

   mpirun -np 4 sun -s -r -vv --datadir=./data
   

Note that the reason behind being able to specify the data directory at the command line is that it enables the executable to be run from the same directory but to use data from different directories that may contain different parameters. For example, if the data1 directory and data2 directory contain different grid data (from previous calls to SUNTANS with the -t and -g flags), then SUNTANS can be run either with

mpirun -np 4 sun -s --datadir=./data1

or with

mpirun -np 4 sun -s --datadir=./data2