By the way, there are also two other optional (command line) parameters that can be put just after ace: 
  java ace {optionsFile} {nInstances} <xcsp3Instance> <options>

  <optionsFile> is the name of a XML file that contains some solver options.
	For example, you can generate such a file with a command like : java dashboard.Control

  <nInstances> is the number of instances to be solved.
  
Let us consider some examples:

  java ace queens-12.xml -s=10
	The instance queens-12.xml is solved (but the solve is stopped after 10 found solutions).

  java ace queens-12.xml -s=10 -varh=Dom 
	The instance queens-12.xml is solved using the variable ordering heuristic 'min Dom'.

  java ace scen11-f8.xml -r_n=1000 -r_c=100
	The instance scen11-f8.xml is solved, with up to 1000 restarts, and a cutoff value (for restarts) initially set to 100 (backtracks).
	The cutoff value is increased at each restart by a factor set to 1.1 (default value).
  
  java ace options.xml queens-12.xml -s=10
	The instance queens-12.xml is solved using the options in the XML file called options.xml (but -s=10 has the priority).

  java main.HeadExtraction scen11-f8.xml
	A minimal unsatisfiable core is extracted.

  
 Finally, to execute all XCSP3 instances in a directory:  
   java ace problem.XCSP3 <directory> 
 and to execute the first k XCSP3 instances in a directory:
   java ace k problem.XCSP3 <directory> 
 