Execution of athena1.0

Once the run parameters have been set by editing the input file, the athena1.0 executable can be run using the -i option to specify the name of the input file. For example, to run the Brio & Wu shocktube use the command

  % athena -i ../tst/1D-mhd/athinput.brio+wu

This will first dump out the values of all input parameters, and then when the code runs, it will print the cycle number and timestep to standard output; when it concludes it will print final diagnostic information. For example, as a simple diagnostic of code performance, the number of zones updated per cpu second is output.

A variety of command line options have been implemented in athena1.0. A list is given by the -h switch:

  % athena -h

  Usage: ../bin/athena [options] [block/par=value ...]
  Options:
    -i <athinput_file>      Specify input file [default 'athinput']
    -d <run_directory>      Specify run dir [default current dir]
    -h                      This Help
    -n                      Parse input, but don't run program

The -d option can be used to create a new directory in which athena1.0 will run and write the output files. The -n option is useful for debugging any parsing errors, as it will dump the contents of all parsed block/parameters.

A value for any of the valid parameter names can also be input from the command line. This, in combination with the -d option, might be useful for parameter surveys. For example, suppose a problem has three parameters, a,b,c, and athena1.0 is to be used for a survey looping over 6, 5 and 7 different values of a,b,c respectively In C-shell notation, this could be accomplished quite easily as follows:

#! /bin/csh -f
  foreach      a  (1.0  1.5  2.0  2.5  3.0  3.5)
    foreach    b  (10   20   30   40   50)
      foreach  c  (1    3    10   30   100  300  1000)
        set dir=run_$a_$b_$c
        mkdir -p $dir
        athena -i your_athinput -d $dir problem/a=$a  problem/b=$b  problem/c=$c > $dir/athena.log
      end
    end
  end

Note that one winds up with 210 different run directories this way. An alternative would be to construct a hierarchy, with a on the top level, and b and c below. This could be accomplished with, for example, set dir=run210/$a/$b/$c.