CL.java

// $Id$
//
// Cassowary Incremental Constraint Solver
// Original Smalltalk Implementation by Alan Borning
// This Java Implementation by Greg J. Badros, <gjb@cs.washington.edu>
// http://www.cs.washington.edu/homes/gjb
// (C) 1998, 1999 Greg J. Badros and Alan Borning
// See ../LICENSE for legal details regarding this software
//
// CL.java
// The enumerations from ClLinearInequality,
// and `global' functions that we want easy to access

package EDU.Washington.grad.gjb.cassowary;

public class CL {
  protected final static boolean fDebugOn = false;
  public static boolean fTraceOn = false; //true;
  protected final static boolean fTraceAdded = false;
  protected final static boolean fGC = false;

  protected static void debugprint(String s)
  { System.err.println(s); }

  protected static void traceprint(String s)
  { System.err.println(s); }

  protected static void fnenterprint(String s)
  { System.err.println("* " + s); }

  protected static void fnexitprint(String s)
  { System.err.println("- " + s); }

  protected void assert(boolean f,String description) throws ExCLInternalError
  { 
    if (!f) { 
      throw new ExCLInternalError("Assertion failed:" + description); 
    }
  }

  protected void assert(boolean f) throws ExCLInternalError
  { 
    if (!f) { 
      throw new ExCLInternalError("Assertion failed");
    }
  }


  public static final byte GEQ = 1;
  public static final byte LEQ = 2;

  public static ClLinearExpression Plus(ClLinearExpression e1, ClLinearExpression e2)
    { return e1.plus(e2); }

  public static ClLinearExpression Plus(ClLinearExpression e1, double e2)
    { return e1.plus(new ClLinearExpression(e2)); }

  public static ClLinearExpression Plus(double e1, ClLinearExpression e2)
    { return (new ClLinearExpression(e1)).plus(e2); }

  public static ClLinearExpression Plus(ClVariable e1, ClLinearExpression e2)
    { return (new ClLinearExpression(e1)).plus(e2); }

  public static ClLinearExpression Plus(ClLinearExpression e1, ClVariable e2)
    { return e1.plus(new ClLinearExpression(e2)); }

  public static ClLinearExpression Plus(ClVariable e1, double e2)
    { return (new ClLinearExpression(e1)).plus(new ClLinearExpression(e2)); }

  public static ClLinearExpression Plus(double e1, ClVariable e2)
    { return (new ClLinearExpression(e1)).plus(new ClLinearExpression(e2)); }

  
  public static ClLinearExpression Minus(ClLinearExpression e1, ClLinearExpression e2)
    { return e1.minus(e2); }

  public static ClLinearExpression Minus(double e1, ClLinearExpression e2)
    { return (new ClLinearExpression(e1)).minus(e2); }

  public static ClLinearExpression Minus(ClLinearExpression e1, double e2)
    { return e1.minus(new ClLinearExpression(e2)); }

  public static ClLinearExpression Times(ClLinearExpression e1, ClLinearExpression e2) 
    throws ExCLNonlinearExpression
    { return e1.times(e2); }

  public static ClLinearExpression Times(ClLinearExpression e1, ClVariable e2) 
    throws ExCLNonlinearExpression
    { return e1.times(new ClLinearExpression(e2)); }

  public static ClLinearExpression Times(ClVariable e1, ClLinearExpression e2) 
    throws ExCLNonlinearExpression
    { return (new ClLinearExpression(e1)).times(e2); }

  public static ClLinearExpression Times(ClLinearExpression e1, double e2) 
    throws ExCLNonlinearExpression
    { return e1.times(new ClLinearExpression(e2)); }

  public static ClLinearExpression Times(double e1, ClLinearExpression e2) 
    throws ExCLNonlinearExpression
    { return (new ClLinearExpression(e1)).times(e2); }

  public static ClLinearExpression Times(double n, ClVariable clv) 
    throws ExCLNonlinearExpression
    { return (new ClLinearExpression(clv,n)); }

  public static ClLinearExpression Times( ClVariable clv, double n) 
    throws ExCLNonlinearExpression
    { return (new ClLinearExpression(clv,n)); }

  public static ClLinearExpression Divide(ClLinearExpression e1, ClLinearExpression e2)
    throws ExCLNonlinearExpression
    { return e1.divide(e2); }

  public static boolean approx(double a, double b)
    {
      double epsilon = 1.0e-8;
      if (a == 0.0) {
	return (Math.abs(b) < epsilon);
      } else if (b == 0.0) {
	return (Math.abs(a) < epsilon);
      } else {
	return (Math.abs(a-b) < Math.abs(a) * epsilon);
      }
    }
  
  public static boolean approx(ClVariable clv, double b)
    {
      return approx(clv.value(),b);
    }
  
  static boolean approx(double a, ClVariable clv)
    {
      return approx(a,clv.value());
    }
}