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best fit algorithm

P: 20
I'm new to programming and need some help figuring out an algorithm.

I need to design some kind of algorithm which will help us define capacity for one of our portfolios....here's the problem explained (also see attached example):

1. The graph defines total capacity, y-axis being $, x-axis being date/time. the bars on the graph represent individual items.

2. What I need to do is place the items on the graph in an optimized manner, minimizing wastage of space. I can break the items vertically but can't break them up horizontally. The goal is to leave as much free space as possible for bigger horizonal items.

3. Items can't overlap each other.

4. See example, I'm currently doing in Access....my procedure takes too long to run and results in overlapped data.

I was wondering there has to be some standard algorithm to do this kind of thing....any ideas would be appreciated....Thanks!

http://forums.devshed.com/attachment...achmentid=7328

take some hints:

iam creat the file by this code

Expand|Select|Wrap|Line Numbers
  1.     import java.awt.*;
  2.  
  3.    import javax.swing.*;
  4.  
  5.    import java.lang.SecurityException;
  6.  
  7.    import java.util.*;       
  8.    import java.util.Formatter;               
  9.    import java.util.FormatterClosedException;
  10.    import java.util.NoSuchElementException;  
  11.    import java.util.Scanner;  
  12.  
  13.    import java.io.*;
  14.    import java.io.FileNotFoundException;     
  15.    import java.io.InputStream;
  16.    import java.io.OutputStream;
  17.    import java.io.FileInputStream;
  18.    import java.io.FileOutputStream;
  19.    import java.io.FileReader;
  20.    import java.io.FileNotFoundException;               
  21.  
  22.   public class FittingAllgorithm
  23.  {
  24.       int memory,dummycount;
  25.      int process;
  26.      int[] bestfit,worstfit,nextfit,firstfit;
  27.  
  28.  
  29.  
  30.      private Formatter output1; // object used to output text to file
  31.  
  32.      // enable user to open file
  33.      public void openFile()
  34.      {
  35.         try
  36.         {
  37.            output1 = new Formatter( "memory.txt" );
  38.         } // end try
  39.         catch ( SecurityException securityException )
  40.        {
  41.           System.err.println(
  42.               "You do not have write access to this file." );
  43.            System.exit( 1 );
  44.         } // end catch
  45.         catch ( FileNotFoundException filesNotFoundException )
  46.         {
  47.            System.err.println( "Error creating file." );
  48.            System.exit( 1 );
  49.         } // end catch
  50.      } // end method openFile
  51.  
  52.      // add records to file
  53.      public void addRecords()
  54.      {
  55.         // object to be written to file
  56.         Job record = new Job();
  57.  
  58.         Scanner input = new Scanner( System.in );
  59.  
  60.        System.out.printf( 
  61.        "%s\n%s\n%s\n%s\n%s\n","********************\n\nFitting Algorithem\n\n********************\n\nThis Create By\n",
  62.        "Khalid Ahmed Almallahy\n20032348\n\n********************\n",
  63.        "Supervesor by",
  64.        "\nMoamar Elyazgi.\n\n********************\n\n",
  65.        "Hint :- \n When You Wont to Exit Press <CTRL>+z\n\n========================================================\n\n" );
  66.  
  67.         System.out.printf( "%s\n%s\n",
  68.            "Enter First Jop 'Process' number must be greater than 0\n  Second Job 'Process'\n  Third Job 'Process'\n  last Job 'Process'",
  69.            "?" );
  70.  
  71.        while ( input.hasNext() ) // loop until end-of-file indicator
  72.         {
  73.            try // output values to file
  74.            {
  75.               // retrieve data to be output
  76.               record.setAccount ( input.nextInt() ); 
  77.               record.setaccount1( input.nextInt() );    
  78.               record.setaccount2( input.nextInt() );       
  79.               record.setaccount3( input.nextInt() );     
  80.  
  81.               if ( record.getAccount() > 0 )
  82.               {
  83.                  // write new record
  84.                  output1.format( "%d %d %d %d \n", 
  85.                     record.getAccount(),
  86.                     record.getaccount1(),
  87.                     record.getaccount2(),       
  88.                     record.getaccount3() );                             
  89.               } // end if
  90.               else
  91.               {
  92.                  System.out.println(
  93.                     "Job number must be greater than 0." );
  94.               } // end else
  95.            } // end try
  96.            catch ( FormatterClosedException formatterClosedException )
  97.            {
  98.               System.err.println( "Error writing to file." );
  99.               return;
  100.            } // end catch
  101.            catch ( NoSuchElementException elementException )
  102.            {
  103.               System.err.println( "Invalid input. Please try again." );
  104.               input.nextLine(); // discard input so user can try again
  105.            } // end catch
  106.  
  107.           System.out.printf( "%s %s\n%s", "\nEnter First Job'Process' number greater than 0,",
  108.               "\nSecond Job 'Process', \nTherd  Job 'Process' \nand So on..", "?\n" );
  109.  
  110.         } // end while
  111.      } // end method addRecords
  112.      // close file
  113.     public void closeFile()
  114.      {
  115.         if ( output1 != null )
  116.            output1.close();
  117.      } // end method closeFile
  118.  
  119.      public void firstfit()
  120.      {
  121.  
  122.       Job record = new Job();
  123.       Scanner input = new Scanner( System.in );
  124.  
  125.      }
  126.  
  127.  
  128.     public static void main( String args[] ) throws FileNotFoundException
  129.      {
  130.          FittingAllgorithm application = new FittingAllgorithm();
  131.  
  132.         application.openFile();
  133.         application.addRecords();
  134.         application.firstfit();
  135.         //application.worstfit();
  136.         //application.bestfit();
  137.         application.closeFile();
  138.      } // end main
  139.   } // end class CreateTextFile
  140.  
  141.  
  142.   /////////////////
  143.  
  144.   and this one
  145.  
  146.  
  147.   public class Job
  148.   {
  149.       private int account;
  150.       private int account1;
  151.       private int account2;
  152.       private int account3;
  153.  
  154.      public Job()
  155.      {
  156.         // constructor
  157.      } 
  158.  
  159.  
  160.      public Job( int acct, int account11, int  account22, int account33 )
  161.      {
  162.         setAccount( acct );
  163.         setaccount1( account11 );
  164.         setaccount2( account22 );
  165.         setaccount3( account33 );
  166.      }
  167.  
  168.  
  169.      public void setAccount( int acct )
  170.      {
  171.         account = acct;
  172.      } 
  173.  
  174.  
  175.      public int getAccount()
  176.     {
  177.         return account;
  178.      }
  179.  
  180.  
  181.      public void setaccount1( int account11 )
  182.      {
  183.         account1 = account11;
  184.      }
  185.  
  186.  
  187.      public int getaccount1()
  188.      {
  189.         return account1;
  190.      } 
  191.  
  192.      public void setaccount2( int account22 )
  193.      {
  194.         account2 = account22;
  195.      } 
  196.  
  197.  
  198.      public int  getaccount2()
  199.      {
  200.         return account2;
  201.      }
  202.  
  203.  
  204.      public void setaccount3( int account33 )
  205.      {
  206.         account3 = account33;
  207.      } 
  208.  
  209.  
  210.      public int getaccount3()
  211.      {
  212.         return account3;
  213.     } 
  214.   } 
  215.  
  216.  
  217. /////////////////////
  218.  
but the problem is how can i division the memory text, the memory text i created but i cannot division it
i wont to division it in to 7 parts each part have 20kb
how can i write this code
if there any one helpe me or any one can write code to division this problem
///////////////////

so i wont to enter number to saved it on the memory text
the memory text have 140kb division into 7 parts each part have 20kb
this is my proble

place help me by wite a code ...
////////////////////////////

i wont to division the memory into 7 parts each part have 20kb so the memory have 140kb , then i wont to enter the nuber into the memory text we must search the hole on the memory that is
empty to enter the number and put it in this hole
there r many algorithem to insert and search the hole but i wont to use the first , best, worst fit algorithems
how can i use this fitting by using this code

hint :::

Satisfy request of size n from list of free holes four basic methods:
First-fit: Allocate the first hole that is big enough.
Best-fit: Allocate the smallest hole that is big enough; must search entire list, unless ordered by size. Produces the smallest leftover hole.
Worst-fit: Allocate the largest hole; must also search entire list. Produces the largest leftover hole.

help me
Oct 17 '07 #1
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6 Replies


Expert 10K+
P: 11,448
I was wondering there has to be some standard algorithm to do this kind of thing....any ideas would be appreciated....Thanks!
Hi, nice to see you back; your problem is a difficult problem to solve; here are
some thoughts about it:

A 'job' has a start time, a time length and a memory requirement. We can describe
it as J(s, t, m). If we do know all parameters s, t and m in advance the problem is
a two dimensional bin packing problem (loosely put: try to fit all those blocks in
the two dimensional TxM rectangle where T is time and M is memory requirement.

This problem is nasty as it is and needs sophisticated (integer) linear solvers
such as iLog's CPlex simplex and interior point plus branch and bound solvers.
Don't take this lightly; it's not stuff for a beginner (no insult intended).

If we *don't* know parameter 's' in advance we're dealing with JIT planning (JIT ==
Just In Time) and there's not much more we can do than indeed apply a simple
first- next- best- or worst fit w.r.t. the memory requirement 'm'; parameter 't' is
fixed so we can't fiddle with that.

I do hope that you're dealing with the second variant because the first variant
takes a lot of processing power and nifty heuristics when if comes to cost factors
if all the requirements are *not* met.

kind regards,

Jos
Oct 17 '07 #2

Expert 10K+
P: 11,448
ps. when it comes to those 'fit'algorithms: Donald Knuth already showed in the
'70s that it doesn't matter much: simply takes the simplest algorithm.

kind regards,

Jos
Oct 17 '07 #3

10K+
P: 13,264
ps. when it comes to those 'fit'algorithms: Donald Knuth already showed in the
'70s that it doesn't matter much: simply takes the simplest algorithm.

kind regards,

Jos
@OP: Revised Simplex algorithm program is not too difficult to make so there is some hope.

@Jos How far would the Nelder Mead method go here? Could it better here than the simplex

P.S Copied to challenges forum
Oct 17 '07 #4

Expert 10K+
P: 11,448
@OP: Revised Simplex algorithm program is not too difficult to make so there is some hope.
<slashing down all hope/> The simple method or an interior point method can just
give an answer on the 'integer relaxation'. After that you have to apply an nasty
'branch and bound' method that are real show stoppers when the number of
integer variables is large; and in this problem this number can be quite large.

@Jos How far would the Nelder Mead method go here? Could it better here than the simplex

P.S Copied to challenges forum
Nope sorry; it won't be of much use as far as I can tell for now ;-)

kind regards,

Jos

ps. I bet this thing will stay unanswered for a long time in the 'Challenges' forum ;-)
Oct 17 '07 #5

P: 20
oh
thank
for non solve my problem
Oct 17 '07 #6

Expert 10K+
P: 11,448
oh
thank
for non solve my problem
?

kind regards,

Jos
Oct 17 '07 #7

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