com.exigen.ie.constrainer.GoalFloatGenerate Maven / Gradle / Ivy

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package com.exigen.ie.constrainer;

///////////////////////////////////////////////////////////////////////////////
/*
 * Copyright Exigen Group 1998, 1999, 2000
 * 320 Amboy Ave., Metuchen, NJ, 08840, USA, www.exigengroup.com
 *
 * The copyright to the computer program(s) herein
 * is the property of Exigen Group, USA. All rights reserved.
 * The program(s) may be used and/or copied only with
 * the written permission of Exigen Group
 * or in accordance with the terms and conditions
 * stipulated in the agreement/contract under which
 * the program(s) have been supplied.
 */
///////////////////////////////////////////////////////////////////////////////

import com.exigen.ie.tools.FastVector;

/**
 * An implementation of a {@link Goal} that generates a solution
 * for the problem with the unknown floating-point variables.
 * 
 * This goal:
 * 

 * Selects the variable using {@link FloatVarSelector}.
 * 
Works with the domain of the variable using or dichotomize algorithm.
 * 
 */
public class GoalFloatGenerate extends GoalImpl
{
  private FloatExpArray      _vars;
  private FloatVarSelector   _var_selector;

  /**
   * The search goals that instantiate each variable.
   */
  private FastVector _goals;

  /**
   * Constructor with a given array of variables.
   */
  public GoalFloatGenerate(FloatExpArray vars)
  {
    this(vars, null);
  }

  /**
   * Constructor with a given array of variables, and variable selector.
   */
  public GoalFloatGenerate(FloatExpArray vars, FloatVarSelector var_selector)
  {
    super(vars.constrainer(), "FloatGenerate");

    _vars = vars;

    _var_selector = ( var_selector != null ?  var_selector :
                                              new FloatVarSelectorFirstUnbound(vars) );

    initGoals();
  }

  /**
   * Returns the array of the variables for this goal.
   */
  public FloatExpArray vars()
  {
    return _vars;
  }

  /**
   * Initializes an array of instantiation goals for the variables.
   */
  void initGoals()
  {
    int size = _vars.size();
    _goals = new FastVector(size);
    for(int i=0; i < size; i++)
    {
      FloatExp exp = _vars.elementAt(i);
      Goal goal = new GoalFloatInstantiate((FloatVar)exp);
      _goals.addElement(goal);
    }
  }

  /**
   * Returns a String representation of this goal.
   * @return a String representation of this goal.
   */
  public String toString()
  {
    return  "FloatGenerate("+_vars.size()+")";
  }

  /**
   * Instantiates all variables in the order defined by the variable selector.
   */
  public Goal execute() throws Failure
  {
    int index = _var_selector.select();

    if (index == -1)
      return null; // all vars are instantiated

    FloatExp var = _vars.elementAt(index);

    Goal search_goal = (Goal)_goals.elementAt(index);

    return new GoalAnd(search_goal,this);
  }

} // ~GoalFloatGenerate