variable.java

Conjugate Gradient Method

import java.util.*;

public class Variable
  extends Value
{
  private String name;
  private static Hashtable ht = new Hashtable();

  private Variable( String name, double v )
  {
    super( v );
    this.name = name;
  }

  public static Variable create( String name, double v )
  {
    Variable V = new Variable( name, v );
    ht.put( name, V );
    return V;
  }

  public static Variable get( String name )
  {
    Object o = ht.get( name );
    if( o instanceof Variable )
      return (Variable)o;
    return null;
  }

  public String toString()
  {
    return name + ":" + getValue();
  }
}