Probs with FormularManager

• To: visad-list@xxxxxxxxxxxxx
• Subject: Probs with FormularManager
• From: Timo Thomas <tthomas@xxxxxxxxxxxxxxxxxxxxxxxx>
• Date: Fri, 11 May 2001 15:48:19 +0200

Hi List, hi Curtis,

I have some Problems with the FormulaManager. The following simple program, 
posted to the list by Curtis on Tue Apr 18 10:29:26 2000, doesn't work as 
expected on my platform (SUSE linux 7.0, kernel 2.2.16):


// Eval.java

import java.rmi.RemoteException;
import visad.*;
import visad.formula.*;

public class Eval {

   public static void main(String[] argv)
     throws VisADException, RemoteException
   {
     // get arguments from command line
     if (argv.length < 3) {
       System.out.println("Please enter three arguments: " +
         "two numbers and a formula.");
       System.exit(1);
     }
     double d1 = 0;
     double d2 = 0;
     try {
       d1 = Double.parseDouble(argv[0]);
       d2 = Double.parseDouble(argv[1]);
     }
     catch (NumberFormatException exc) {
       System.out.println("First two arguments must be numbers.");
       System.exit(2);
     }
     String formula = argv[2];

     // create two VisAD Data objects that store floating point values
     Real x = new Real(d1);
     Real y = new Real(d2);

     // create formula manager
     FormulaManager fman = FormulaUtil.createStandardManager();

     // register Data objects with formula manager
     fman.setThing("x", x);
     fman.setThing("y", y);

     // assign formula to new variable
     fman.assignFormula("f", formula);

     // wait for formula to finish computing, just to be safe
     fman.waitForFormula("f");

     // get value of function from formula manager
     Real f = (Real) fman.getThing("f");

     // print out results
     System.out.println("x = " + x.getValue() + ", y = " + y.getValue());
     System.out.println("f(x,y) = " + formula + " = " + f.getValue());
   }

}


1. Problem/Error: Eval doesn't return. E.g. 

~/da/test/visad: java Eval 3 4 x+y  
x = 3.0, y = 4.0
f(x,y) = x+y = 7.0

does produce the correct output, but the process isn't exiting.

2. The FormularManager doesn't work if the to be calculated formula doesn't 
contain any variable. E.g. 

Eval 3 4 90+35

doesn't produce any output nor does it return with an exception or something.

Thanks for any help,
Timo

-- 
__.__________
 |lmo |homas

• Follow-Ups:
  • Re: Probs with FormularManager
    • From: Curtis Rueden