Programming Forums > Application Development > Java

thenewkid · Jan 30th, 2007, 9:20 PM

hey all, for my programming course i was to write a progam that uses a combinatorial search to find a solution, the problem is of course, that as the amount of data increases so is the time to find a solution. What i want to do is to interrupt such a time taking search and go onto the next possible candidate that might produce a correct answer. Without using threads is it possible to employ a timer of some sort so when the processing takes too long it could interrupt and tell it to move on to the next candidate? This is the Knight Tour problem, i guess many of you have dealt with it one point in your lifetime. Any advice greately appreciated.

ReggaetonKing · Jan 30th, 2007, 9:30 PM

I would recommend looking into some more efficient ways in organizing your data. Maybe sorting your data would make the search A LOT more manageable.

Instead of having your data as just some random places just organize and use binary search.

thenewkid · Jan 30th, 2007, 9:43 PM

yes i know it could be done more efficiently if more advanced data structures than simple array have been used, thats not the point here, Im looking for the way to interrupt something that takes to long to arrive at the correct answer.

Arevos · Jan 31st, 2007, 3:46 AM

Why not just check the time at each iteration or recursion of the loop? It seems to me as if you wouldn't need threads.

thenewkid · Jan 31st, 2007, 9:51 AM

you just made me think of something that could actually work, ill try something similar...ill let you all know if it worked, thanks

thenewkid · Jan 31st, 2007, 8:36 PM

I found a place in my code where i could call elapsed() which made following code usable. Sometimes when i overthink a problem i do not see really simple solutions, I tend to think of too complicated stuff....are u like that? hehe, i mean look at this:

(Toggle Plain Text)

import java.util.Date;

public class myTimer {
   private final Date start;
   private Date current;
   
   public myTimer()  {
      start = new Date();
      current = null;
   }
   
   public boolean elapsed(int sec) {
      current = new Date();
      long difference = current.getTime() - start.getTime();
      if(difference >= (long)sec * 1000)
         return true;
      else return false;
   }
}

Arevos! thanks for opening my eyes lol

titaniumdecoy · Jan 31st, 2007, 9:24 PM

Your code creates a new Date object every time elapsed is called. You should use System.currentTimeMillis() instead.

You should also take into account the fact that performing such a check on each iteration of a loop will cost time and processing power, albeit a miniscule amount.

thenewkid · Feb 2nd, 2007, 7:45 PM

yes, i've relized it, thanks for pointing me to the right function

Jan 30th, 2007, 9:20 PM	#1
thenewkid Programmer Join Date: Sep 2004 Location: New Jersey Posts: 36 Rep Power: 0	interrupting current execution hey all, for my programming course i was to write a progam that uses a combinatorial search to find a solution, the problem is of course, that as the amount of data increases so is the time to find a solution. What i want to do is to interrupt such a time taking search and go onto the next possible candidate that might produce a correct answer. Without using threads is it possible to employ a timer of some sort so when the processing takes too long it could interrupt and tell it to move on to the next candidate? This is the Knight Tour problem, i guess many of you have dealt with it one point in your lifetime. Any advice greately appreciated.

Jan 30th, 2007, 9:30 PM	#2
ReggaetonKing Sexy Programmer Join Date: Nov 2005 Location: New Jersey Posts: 891 Rep Power: 3	I would recommend looking into some more efficient ways in organizing your data. Maybe sorting your data would make the search A LOT more manageable. Instead of having your data as just some random places just organize and use binary search. __________________ I would love to change the world, but they won't give me the source code!

Jan 31st, 2007, 8:36 PM	#6
thenewkid Programmer Join Date: Sep 2004 Location: New Jersey Posts: 36 Rep Power: 0	I found a place in my code where i could call elapsed() which made following code usable. Sometimes when i overthink a problem i do not see really simple solutions, I tend to think of too complicated stuff....are u like that? hehe, i mean look at this: (Toggle Plain Text) import java.util.Date; public class myTimer { private final Date start; private Date current; public myTimer() { start = new Date(); current = null; } public boolean elapsed(int sec) { current = new Date(); long difference = current.getTime() - start.getTime(); if(difference >= (long)sec * 1000) return true; else return false; } } import java.util.Date; public class myTimer { private final Date start; private Date current; public myTimer() { start = new Date(); current = null; } public boolean elapsed(int sec) { current = new Date(); long difference = current.getTime() - start.getTime(); if(difference >= (long)sec * 1000) return true; else return false; } } Arevos! thanks for opening my eyes lol

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Jan 30th, 2007, 9:43 PM	#3
thenewkid Programmer Join Date: Sep 2004 Location: New Jersey Posts: 36 Rep Power: 0	yes i know it could be done more efficiently if more advanced data structures than simple array have been used, thats not the point here, Im looking for the way to interrupt something that takes to long to arrive at the correct answer.

Jan 31st, 2007, 3:46 AM	#4
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 5	Why not just check the time at each iteration or recursion of the loop? It seems to me as if you wouldn't need threads.

Jan 31st, 2007, 9:51 AM	#5
thenewkid Programmer Join Date: Sep 2004 Location: New Jersey Posts: 36 Rep Power: 0	you just made me think of something that could actually work, ill try something similar...ill let you all know if it worked, thanks

Jan 31st, 2007, 9:24 PM	#7
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 856 Rep Power: 3	Your code creates a new Date object every time elapsed is called. You should use System.currentTimeMillis() instead. You should also take into account the fact that performing such a check on each iteration of a loop will cost time and processing power, albeit a miniscule amount.

Feb 2nd, 2007, 7:45 PM	#8
thenewkid Programmer Join Date: Sep 2004 Location: New Jersey Posts: 36 Rep Power: 0	yes, i've relized it, thanks for pointing me to the right function

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Programming Forums > Application Development > Java

interrupting current execution