execute {
   var fc = cp.factory;

   var search_sequence = new Array(seq[1]); // ends to middle instantiation
   for (var i = 1; i <= NbCompositions; i++) {
   		if (i%2)
   			search_sequence[i] = seq[(i+1)/2];
   		else
   			search_sequence[i] = seq[NbCompositions - (i/2) + 1];
   }

   var phase1 = fc.searchPhase(search_sequence);
   cp.setSearchPhases(phase1);
}