User dependent changes and the file swaninit

SWAN allows you to customize the input and the output to the wishes of your department, company or institute or yourself. This can be done by changing the settings in the initialisation file swaninit, which is created during the first time SWAN is executed on your computer system. The changes in swaninit only affect the runs executed in the directory that contains that file.


A typical initialisation file swaninit may look like:

    4                               version of initialisation file
Delft University of Technology      name of institute
    3                               command file ref. number
INPUT                               command file name
    4                               print file ref. number
PRINT                               print file name
    4                               test file ref. number
                                    test file name
    6                               screen ref. number
99999                               highest file ref. number
$                                   comment identifier
[TAB]                               TAB character
\                                   dir sep char in input file
/                                   dir sep char replacing previous one
    1                               default time coding option
  100                               speed of processor   1
  100                               speed of processor   2
  100                               speed of processor   3
  100                               speed of processor   4

Explanation:

• The version number of the initialisation file is included in the file so that SWAN can verify whether the file it reads is a valid initialisation file. The current version is 4.
• The initialisation file provides a character string containing the name of the institute that may carry out the computations or modifying the source code. You may assign it to the name of your institute instead of Delft University of Technology, which is the present value.
• The standard input file and standard print file are usually named INPUT and PRINT, respectively. You may rename these files, if appropriate.
• The unit reference numbers for the input and print files are set to 3 and 4, respectively. If necessary, you can change these numbers into the standard input and output unit numbers for your installation. Another unit reference number is foreseen for output to screen and it set to 6. This is useful if print output is lost due to abnormal end of the program, while information about the reason is expected to be in the print file. There is also a unit number for a separate test print file. In the version that you downloaded from SWAN homepage, this is equal to that of the print file so that test output will appear on the same file as the standard print output.
• The comment identifier to be used in the command file is usually '$', but on some computer system this may be inappropriate because a line beginning with '$' is interpreted as a command for the corresponding operating system (e.g., VAX systems). If necessary, change to '!'.
• To insert [TAB] in the initialisation file, just use the TAB key on your keyboard.
• Depending on the operating system, the first directory separation character in swaninit, as used in the input file, may be replaced by the second one, if appropriate.
• Date and time can be read and written according to various options. The following options are available:
  1. 19870530.153000 (ISO-notation)
  2. 30-May-87 15:30:00
  3. 05/30/87 15:30:00
  4. 15:30:00
  5. 87/05/30 15:30:00
  6. 8705301530 (WAM-equivalence)
  Note that the ISO-notation has no millenium problem, therefore the ISO-notation is recommended. In case of other options, the range of valid dates is in between January 1, 1911 and December 31, 2010 (both inclusive).
• In case of a parallel MPI run at the machine having a number of independent processors, it is important to assign subdomains representing appropriate amounts of work to each processor. Usually, this refers to an equal number of grid points per subdomain. However, if the computer has processors which are not all equally fast (a so-called heterogeneous machine), then the sizes of the subdomains depend on the speed of the processors. Faster processors should deal with more grid points than slower ones. Therefore, if necessary, a list of non-default processor speeds is provided. The given speeds are in % of default = 100%. As an illustrating example, we have two PC's connected via an Ethernet switch of which the first one is 1.5 times faster than the second one. The list would be

           150    speed of processor 1
           100    speed of processor 2
  

  Based on this list, SWAN will automatically distribute the total number of active grid points over two subdomains in an appropriate manner. Referring to the above example, with 1000 active points, the first and second subdomains will contain 600 and 400 grid points, respectively.