Choco

ChocLet was designed to be interoperable with Choco library. The global identifier choco, allows to declare variables, define constraints and solve a model.

Choco binding

The choco is a binding of a Choco Model instance, where some function are overriden to ease the usage.

let a = choco.int (0, 10);
// a is an intVar

println (a); //IV_1 = {0,1,2,3,4,5...,10}

Choco Model direct binding

The following function are directly callable with choco object. The prototype of the Java function are respected (direct binding).

Choco custom binding

You can add your own binding to choco Model methods.

in choco {
    def allDifferents -> ChocoConstraint;
}

let a = [choco.int (0, 10), choco.int (1, 3)];
choco.allDifferents (a).post ();

Choco model function override

The following function are provided by choco object.

• post (constraints...) -> void | This function will post the constraints to the model

  • Parameters :
    • constraints, an set of Constraints

• solve () -> bool | This function is a binding of the solve function, it will actually call the following Java code :

  • Returns: is the model satisfied by current solution ?

  Solver solver = model.getSolver ();
  return solver.solve ();
  

• clean () -> void | Clean the model, by removing all the posted variables and constraints
• restart () -> void | Restart the solving search, by calling the solver function restart
• print () -> void | Print the model to the screen
• strategy (varSelect, valSelect[, vars]) -> void | This function is used to monitor the solving execution Described in this section Solving

• onOpenNode (onOpen, onClose) -> void

  • Parameters :
    • onOpen : a function fn () -> void
    • onClose : a function fn () -> void

• printStats () -> void

  model.getSolver ().printStatistics ();
  

• solveOptimal () -> bool | Solve the problem until the optimal solution is found :

  Solution s = new Solution (model);
  while (model.getSolver ().solve ()) s.record ();
  boolean feasible = model.getSolver ().isFeasible () == ESat.TRUE;
  
  if (feasible) s.restore ();
  return feasible;
  

• exportJSON (filename) -> void | Export the model to a json file

  • Parameters:
    • filename : the name of the file in which the exportation will be done