LinearProgramming in Java

C.R.Muthukumar

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Posts: 59

posted 18 years ago

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Hello Java Programmers
The subject OperationsRearch covers a wide no of application with its algorithms though its use under Java, seems to be little compared to C++programming .A try has been made in java for the most popular LinearProgramming topic, the codes are errorless.but finshing requires more subtler tuning than that of C++.The codes can be modified to render good output,can I know whether there is any Java coded OperationResarch Text book ,if this seems cumbersome,Thanks in advance
AS Always
C.R.Muthukumar

import java.io.*;
import java.text.*;
import java.awt.*;
import java.awt.event.ActionEvent.*;
import java.awt.event.WindowEvent;
import java.lang.Math.*;
import java.lang.Character;
import java.lang.Float;
import java.lang.Integer;
import java.lang.Object;
import java.lang.Boolean;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.RandomAccess;
 
public class Linear2 extends Frame{
static final int M=15;
     static final int N=30;
   static double PENALTY =-900.00;
   static final double EPS=0.00001;
    static int i,j;
      static char res_in_file;
       static char yn;
//readfile1
//writefile3
//result2
// resultfile4
 static RandomAccessFile raf1,raf2,raf3,raf4;
   static int mm;
static int k;
static int m;
static int n;
     static int kr,kc,kf;
  float top[];
  float base[];
  float left[];
   char sign[];
       int basic[];
   float x[][];
 
float keyNo;
static float obj;
 
public void readData(){
int i=0;
 
  for(j=0;j < m; j++){
  for( int j = 0; j < m; j++ )
        {
            if( x[ j ]== null )
                System.out.print( "(null)" );
            else
            {
                for( j = 0; j < x[i].length; j++ )
                    System.out.print( x[ i ][ j ] + " " );
                //System.out.print( );
            }
        }
System.out.print(" \n x[i][j]"+ " ");
System.out.print(" \n sign[i]"+ " ");
System.out.print(" \n left[i]"+ " ");
}
}
public void addSlack()
{
int i;
for(i=0;i<m;i++)
{
if(sign[i] == '<'|| sign[i] == '>')
{
  n++;
for(int i1=0;i1<m;i1++)
  x[i1][n-1]=0;
if(sign[i] == '<')
{
x[i][n-1]=1;
top[n-1]=0;
basic[i]=n-1;
}
else
{
x[i][n-1]= -1;
     top[n-1]= 0;
}
}
}
}
public void addArti()
{
 int i;
for(i=0;i<n;i++)
if (sign[i] == '='|| sign[i] == '>')
{
n++;
for(int i1=0;i1<m;i1++)
x[i][n-1]=0;
x[i][n-1]=-900;
top[n-1] =-900;
basic[i]= n-1;
}
}
public void findbase()
{
int i,j;
for(j=0;j<n;j++)
{
base[j]=0;
for(i=0;i<m;i++)
base[j] += x[i][j] * top[basic[i]];
base[j]= base[j]-top[j];
}
}
public void display()
{
int i,j;
for(j=0;j<n;j++)
System.out.println("\n top[j]"+ j);
 
for(i=0;i<m;i++)
{
System.out.print("\n top[basic[i]]" + i);
System.out.print("\n basic[i])+1"+ i);
System.out.print("\n left[i]"+ i);
 
for(j=0;j<n;j++)
System.out.println("\n x[i][j] "+ j);
 
for(j=0;j<n;j++)
System.out.println("\n base[j]"+j);
}
}
public int keyRow(int k)
{
int i;
float ratio;
float min =100000;
int l= - 1;
for(i=0;i<m;i++)
{
if(x[i][k] < EPS && left[i] > EPS)
continue;
else
ratio = left[i]/x[i][k];
if(ratio < -EPS)
continue;
else
if(left[i]/x[i][k] < min)
{
min = left[i]/x[i][k];
l=i++;
}
}
if(l == -1)
{
System.out.println("\n UnboundedSolution");
}
return 1;
}
public int keyColumn()
{
int j;
float min =0;
int l = -1;
for(j=0;j<n;j++)
{
if(base[j] < min)
{
 min = base[j];
  l=j;
}
}
return 1;
}
 
public void modify(int kr,int kc)
{
  int i,j;
 
float keyNo;
float temp[]=new float[M];
for(i=0;i<m;i++)
temp[i] = x[i][kc];
basic[kr]=kc;
keyNo=x[kr][kc];
for(j=0;j<n;j++)
x[kr][j]=x[kr][j]/keyNo;
left[kr]=left[kr]/keyNo;
for(i=0;i<m;i++)
{
if(i== kr)
continue;
left[i]=left[i]-left[kr] * temp[i];
}
for(i=0;i<m;i++)
{
  if(i==kr)
continue;
else
for(j=0;j<n;j++)
x[i][j]=x[i][j]- temp[i] * x[kr][j];
}
obj=00.0f;
for (i=0;i<m;i++)
obj=obj+top[basic[i]] * left[i];
 
}
 
public int result()throws Exception
{
int i=0;
int feasible=1;
{
RandomAccessFile raf3 = new RandomAccessFile("myfile3.txt","rw");
 
  raf3.seek(raf3.length());
for (i=0;i<m;i++)
obj=obj+top[basic[i]] * left[i];
for(i=0;i<m;i++)
if((top[basic[i]] < (PENALTY +0.01) && left[i] > EPS))
{
 if(false);
 raf3.writeFloat(obj);
 System.out.print("\n OptimalValue of Objective function " + obj );
break;
}
if(true)
{
for(i=0;i<m;i++)
{
raf3.writeInt(i);
System.out.print(" \n [i]+1"+ "   ");
System.out.print("\n [i]"+ "  ");
}
if(res_in_file == 'y')
{
 for(i=0;i<m;i++)
  {
  obj=basic[i]+1;
  }
}else{
if(res_in_file == 'Y')
{
     for(i=0;i<m;i++)
     {
 obj=left[i];
     }
raf3.writeFloat(obj);
}
   System.out.print("Solution is infeasible");
}
}
return (int)obj;
}
}
public void readFile() throws Exception
 
{
RandomAccessFile raf1= new RandomAccessFile("myfile1.txt","rw");
 raf1.seek(raf1.length());
for(int i=0; i < raf1.length();i++)
{
try
{
     int mm=raf1.readInt();
      k=raf1.readInt();
      m=raf1.readInt();
      n=k;
for(j=0;j<k;j++)
 {
top[j]= j;
    if(mm==2)
    top[j]=0-top[j];
 }
for(i=0;i<m;i++)
 {
   for(j=0;j<k;j++)
   top[j] = raf1.readInt();
    do{
      sign[i]=raf1.readChar();
      left[i]=raf1.readInt();
     }while(true);
     }
     System.out.print((int)mm);
}
catch(EOFException e)
{
break;
}
}
}
public void writeFile(){
 
int i,j;
 
try
{
RandomAccessFile raf2= new RandomAccessFile("myfile2.txt","rw");
raf2.seek(raf1.length());
while(raf1.getFilePointer()< raf1.length())
 
raf2.writeInt(mm);
raf2.writeInt(k);
raf2.writeInt(m);
  n=k;
if(mm==1){
for(j=0;j<k;j++)
top[j]=j;
for (j=0;j<top.length;j++)
{
 System.out.print((int)j);
}
}
else
for(i=0;i<m;i++)
  for (j=0;j<k;j++){
 x[i][j]=i;
}
for(i=0;i<x.length;i++){
 
System.out.print((int)i);
  }
  for(i=0;i<sign.length;i++)
 
    {
raf2.writeInt(i);
    System.out.print((int)i);
 
    }
 
    left[i]=i;
    for(i=0;i<left.length;i++)
    {
raf2.writeInt(i);
System.out.print((int)i);
 
    }
 
raf2.close();
 
}
catch(Exception e)
{}
 
}
public void resultFile()
  {
int i,j=0;
try
 {
    RandomAccessFile raf4 = new RandomAccessFile("myfile4.txt","rw");
      raf4.seek(raf4.length());
   while(raf4.getFilePointer() < raf4.length())
   {
     {
       i=raf4.readInt();
  }
   }
       for(j=0;j<n;j++)
    top[j]=j;
    for(j=0;j<top.length;j++){
     raf4.writeInt(j);
 raf4.seek(0);
     j=raf4.readInt();
     System.out.print((int)j);
 }
 
  for(j=0;j<n;j++)
  for(i=0;i<m;i++)
{
 top[basic[i]] = i+1;
for(i=0;i<top.length;i++)
 for(i=0;i<basic.length;i++)
{
raf4.writeInt(i);
System.out.print((int)i);
 
}
 
for(j=0;j<n;j++)
 x[i][j]=i;
 for(i=0;i<x.length;i++)
 for(j=0;j<x.length;j++)
 {
       raf4.writeInt(i);
 System.out.print((int)i);
}
for(j=0;j<n;j++)
obj=j;
{
raf4.writeFloat(obj);
  System.out.print((int)obj);
}
for(j=0;j<n;j++)
base[j]=j;
{
raf4.writeFloat(obj);
System.out.print((int)j);
}
}
}
catch(Exception e)
{};
}
 
public static void main(String args[])throws IllegalAccessException,Exception
{
//RandomAccessFile raf1;
raf1= new RandomAccessFile("myfile1.txt","rw");
   // RandomAccessFile raf2;
   raf2= new RandomAccessFile("myfile2.txt","rw");
   //RandomAccessFile raf3;
   raf3= new RandomAccessFile("myfile3.txt","rw");
//RandomAccessFile raf4;
raf4= new RandomAccessFile("myfile4.txt","rw");
 
   Frame fme = new Frame();
  fme.addWindowListener(new WindowAdapter()
      {
   public void windowClosed(WindowEvent e)
    {System.exit(0);}
       });
 
      Linear2 lp;
      lp= new Linear2();
  int kc=0;
  int kr=0;
      int kf=0;
     //char fres[]={15};
      String s1;
 BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
             s1=br.readLine();
     System.out.print("\n  Linear2 ");
            s1=br.readLine();
  System.out.print("\n Enter no of Objective variables (k = of the maxy/mini eqn): " + " ");
s1=br.readLine();
System.out.print("\n Enter the coef of Objective Functions :(  coef of maxy/mini eqn) :"+ " ");
s1=br.readLine();
System.out.print("\n Enter no of Constraints (m): " + " ");
s1=br.readLine();
  System.out.print("\n Enter the Constraints :(  coef of constraints from eqns for both left and right sides) "+ " ");
s1=br.readLine();
System.out.print("\n Enter > for >_ and < for _<: "+ " ");
s1=br.readLine();
 //System.out.println("\n Read data from Key board (1) or File(2):" + " ");
 //     s1=br.readLine();
System.out.print("\n File name to write result (myfile2):"+" ");
s1=br.readLine();
System.out.print("\n Do you want to maximise(1) or minimize(2)  (mm):" + " ");
s1=br.readLine();
   for(j=0;j<k;j++)
   {
      if(mm==2)
      System.out.print(" \n top[j]=0-top[j]"+  j +"");
      else
      System.out.print(" \ntop[j]"+ j+" ");
    }
    System.out.print("\n File name to read (myfile1):"+ " ");
  s1=br.readLine();
      System.out.print("\n Enter data from keyboard (1) or file(2)(kf):" + " ");
   s1=br.readLine();
      if(kf==1)
      {
      lp.readData();
      }
      System.out.print("\n Output required in file (yn):" + " ");
      s1=br.readLine();
         if( yn =='y' || yn == 'Y')
        {
     lp.writeFile();
     }
      System.out.print("\n Store data in disc file (y/n):"+ " ");
        s1=br.readLine();
       if(res_in_file == 'y' || res_in_file =='Y')
       {
       lp.readFile();
       }
    lp.addSlack();
    lp.addArti();
    lp.findbase();
    lp.display();
     lp.resultFile();
       i=1;
     for(; :wink: {
     kc= lp.keyColumn();
      if(kc == -1)break;
      s1=br.readLine();
       System.out.print(" Linear2 " + i);
       s1=br.readLine();
     System.out.print("\n ***********\n");
     s1=br.readLine();
      System.out.print("\n KeyColumn : " + kc);
     if(res_in_file == 'Y'){
        lp.resultFile();
        lp.keyRow(kc);
 
    kr=lp.keyRow(kc);
}
    s1=br.readLine();
        System.out.print("\n KeyRow:  "  + kr);
        lp.modify(kr,kc);
       lp.findbase();
       lp.display();
       i++;
 
     }
    lp.result();
 
}
}

Ernest Friedman-Hill

author and iconoclast

Posts: 24208

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posted 18 years ago

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Do you have a question?

[Jess in Action][AskingGoodQuestions]

C.R.Muthukumar

Ranch Hand

Posts: 59

posted 17 years ago

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Originally posted by Ernest Friedman-Hill:
Do you have a question?

Hello Java-Prodigies.,
Yes, the long awaited question is very comprehensive now (After the current operations research topic which created a rather ambiguity as to for the difference between dramatist and a needy person as per above posted request especially so for a person who has been waiting long for an equivalent program in java to that of c++ on subject viz., linear programming(Optimisation under Operations research)to fetch a solution though not an OperationsResearchBook, for which the author amazingly explained about the same under googly usage.While thanking for it,however, for me a googly approach is a grandmilestone though there are experts and specialists like in the game of cricket ie),if one is googly bowler,there is yet another "DonkeyDroppers,TopSpinners,or lefthanded googly bowlers
used to be called chinaman" etc.
please arrange to treat the above request in the more sportive spirit, and offer guidelines.
The above post refers to the old stuff dating back a couple of years/months old need completion for .Plese correct me if I am wrong.
Thanks
As
C.R.Muthukumar

Bear Bibeault

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Posts: 67762

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