package joptima;

/**
 * 
A contract with functions that want to participate in optimization.
 *
 * 

 * Function parameters are provided as an array of delegates.  To set the
 * parameters prior to calculating the value of the fuction one must call
 * {@link Parameter#set} which sets member fields using reflection.  Once
 * all the parameters have been set, {@link #calculate} returns the value
 * of the function at the given coordinate.
 * 
 *
 * @author Dejan Vucinic <dvucinic@users.sourceforge.net>
 */
public interface Function {

 /**
  * Lists all the mutable parameters to this function.
  * @return a {@link Parameter}[] of delegates that access the proper
  * member variables.
  */
  public Parameter[] getParameters();

 /**
  * Calculates the value of the function at the given point using the
  * preset parameters.
  * @param x the x coordinate to calculate the function at
  * @return the value of the function at the given coordinate
  */
  public double /* y = */ calculate(double x);

 /**
  * Gets the (user-settable) name of this function.
  * @return the name of the function
  */
  public String getName();

 /**
  * Overrides the default function name.
  *
  * @param newname the new name for the function
  */
  public void setName(String newname);

}