The program produces three kinds of output:

• STDERR (terminal): occasional messages about what the algorithm is doing, how much of the work has been performed, and error messages.
• STDOUT (terminal, unless redirected to a file with '>'): a summary of the execution, including data about the instance itself (file name, size, etc.), execution parameters (how many iterations, what kind of local search procedure, etc.). Each line contains one piece of information, given in the following format:

  <keyword> <value>

  Keywords should be self-descriptive. The most relevant are:

  • instance: instance name, taken from the file name given in the command line (without the path and the extension);

  • centers: number of centers specified (i.e., the value of p in the p-median problem);

  • bestsol: value of the best solution found;

  • cputime: total CPU time spent by the program.

• FILE (file name specified by the "-output" option in the command line): the solution itself, with which facilities should be open and the corresponding assigments.

  WARNING: If no file name is specified, the solution will not be output (but its value will, to stdout ).

Each line in the output file begins with a single character (indicating which kind of line that is) followed by a space and one or more pieces of information. The line types are:

  i <string>   : instance name
  p <integer>  : number of centers (open facilities)
  n <integer>  : number of nodes
  v <double>   : solution value
  f <integer>  : indicates that a particular facility is open (i.e.,
                 belongs to the solution); there is one f line for
	         each open facility
  a <u> <f> <c>: indicates that user <u> should be assigned to 
                 facility <f> in the solution, and <c> would be the cost
	         of this assignment. <u> and <f> are integers, and <c>
	         is a double.