How to declare int variables dynamically in java without using external LP file?

View: New views

2 Messages — Rating Filter: Alert me

How to declare int variables dynamically in java without using external LP file?

by rcrmca :: Rate this Message:

Reply to Author | View Threaded | Show Only this Message

Can anybody please tell me how to declare int variables dynamically in java without using external LP file?

here is the example program and i want to add int x,y in Integer definition.

/*
*

P = max: 25.0 x + 40.0 y;
25.0 x <= 100.0;
40.0 y <= 80.0;

*
* Created on October 8, 2009, 2:08 PM
*/

/**
*
* @author christopher
*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import lpsolve.*;

public class Demo {

public Demo() {
}

public int execute() throws LpSolveException {
LpSolve lp;
int Ncol, j, ret = 0;

/* We will build the model row by row
So we start with creating a model with 0 rows and 2 columns */
Ncol = 2; /* there are two variables in the model */

/* create space large enough for one row */
int[] colno = new int[Ncol];
double[] row = new double[Ncol];

lp = LpSolve.makeLp(0, Ncol);
if(lp.getLp() == 0)
ret = 1; /* couldn't construct a new model... */

if(ret == 0) {
/* let us name our variables. Not required, but can be useful for debugging */
lp.setColName(1, "x");
lp.setColName(2, "y");

lp.setAddRowmode(true); /* makes building the model faster if it is done rows by row */

/* construct first row (110 x + 30 y <= 4000) */
j = 0;

colno[j] = 1; /* first column */
row[j++] = 25.0;

colno[j] = 2; /* second column */
row[j++] = 0;

/* add the row to lpsolve */
lp.addConstraintex(j, row, colno, LpSolve.LE, 100);
}

if(ret == 0) {
/* construct second row (x + y <= 75) */
j = 0;

colno[j] = 1; /* first column */
row[j++] = 0;

colno[j] = 2; /* second column */
row[j++] = 40.0;

/* add the row to lpsolve */
lp.addConstraintex(j, row, colno, LpSolve.LE, 80);
}

if(ret == 0) {
lp.setAddRowmode(false); /* rowmode should be turned off again when done building the model */

/* set the objective function (143 x + 60 y) */
j = 0;

colno[j] = 1; /* first column */
row[j++] = 25.0;

colno[j] = 2; /* second column */
row[j++] = 40.0;

/* set the objective in lpsolve */
lp.setObjFnex(j, row, colno);
}

if(ret == 0) {
/* set the object direction to maximize */
lp.setMaxim();

/* just out of curioucity, now generate the model in lp format in file christ.lp */
lp.writeLp("christ.lp");

/* I only want to see important messages on screen while solving */
lp.setVerbose(LpSolve.IMPORTANT);

/* Now let lpsolve calculate a solution */
ret = lp.solve();
if(ret == LpSolve.OPTIMAL)
ret = 0;
else
ret = 5;
}

if(ret == 0) {
/* a solution is calculated, now lets get some results */

/* objective value */
System.out.println("Objective value: " + lp.getObjective());

/* variable values */
lp.getVariables(row);
for(j = 0; j < Ncol; j++)
System.out.println(lp.getColName(j + 1) + ": " + row[j]);

/* we are done now */
}

/* clean up such that all used memory by lpsolve is freed */
if(lp.getLp() != 0)
lp.deleteLp();

return(ret);
}

public static void main(String[] args) {
try {
//System.load("\\LpFiles\\lpsolve55j.dll");
new Demo().execute();
}
catch (LpSolveException e) {
e.printStackTrace();
}
}
}

i want this christ.LP has int declaration as,

/* Objective function */
max: +25 x +40 y;

/* Constraints */
+25 x <= 100;
+40 y <= 80;

/* Integer Definitions */
int x,y;

How can i?

Re: How to declare int variables dynamically in java without using external LP f

by peter_notebaert :: Rate this Message:

Reply to Author | View Threaded | Show Only this Message

http://lpsolve.sourceforge.net/5.5/Java/docs/api/lpsolve/LpSolve.html#setInt(int, boolean)

Peter

--- In lp_solve@..., "rcrmca" <rcrmca@...> wrote:

>
> Can anybody please tell me how to declare int variables dynamically in java without using external LP file?
>
> here is the example program and i want to add int x,y in Integer definition.
>
> /*
> *
>
> P = max: 25.0 x + 40.0 y;
> 25.0 x <= 100.0;
> 40.0 y <= 80.0;
>
>
>
> *
> * Created on October 8, 2009, 2:08 PM
> */
>
> /**
> *
> * @author christopher
> */
> import java.io.BufferedReader;
> import java.io.IOException;
> import java.io.InputStreamReader;
>
> import lpsolve.*;
>
> public class Demo {
>
> public Demo() {
> }
>
> public int execute() throws LpSolveException {
> LpSolve lp;
> int Ncol, j, ret = 0;
>
> /* We will build the model row by row
> So we start with creating a model with 0 rows and 2 columns */
> Ncol = 2; /* there are two variables in the model */
>
> /* create space large enough for one row */
> int[] colno = new int[Ncol];
> double[] row = new double[Ncol];
>
> lp = LpSolve.makeLp(0, Ncol);
> if(lp.getLp() == 0)
> ret = 1; /* couldn't construct a new model... */
>
> if(ret == 0) {
> /* let us name our variables. Not required, but can be useful for debugging */
> lp.setColName(1, "x");
> lp.setColName(2, "y");
>
> lp.setAddRowmode(true); /* makes building the model faster if it is done rows by row */
>
> /* construct first row (110 x + 30 y <= 4000) */
> j = 0;
>
> colno[j] = 1; /* first column */
> row[j++] = 25.0;
>
> colno[j] = 2; /* second column */
> row[j++] = 0;
>
> /* add the row to lpsolve */
> lp.addConstraintex(j, row, colno, LpSolve.LE, 100);
> }
>
> if(ret == 0) {
> /* construct second row (x + y <= 75) */
> j = 0;
>
> colno[j] = 1; /* first column */
> row[j++] = 0;
>
> colno[j] = 2; /* second column */
> row[j++] = 40.0;
>
> /* add the row to lpsolve */
> lp.addConstraintex(j, row, colno, LpSolve.LE, 80);
> }
>
> if(ret == 0) {
> lp.setAddRowmode(false); /* rowmode should be turned off again when done building the model */
>
> /* set the objective function (143 x + 60 y) */
> j = 0;
>
> colno[j] = 1; /* first column */
> row[j++] = 25.0;
>
> colno[j] = 2; /* second column */
> row[j++] = 40.0;
>
> /* set the objective in lpsolve */
> lp.setObjFnex(j, row, colno);
> }
>
> if(ret == 0) {
> /* set the object direction to maximize */
> lp.setMaxim();
>
> /* just out of curioucity, now generate the model in lp format in file christ.lp */
> lp.writeLp("christ.lp");
>
> /* I only want to see important messages on screen while solving */
> lp.setVerbose(LpSolve.IMPORTANT);
>
> /* Now let lpsolve calculate a solution */
> ret = lp.solve();
> if(ret == LpSolve.OPTIMAL)
> ret = 0;
> else
> ret = 5;
> }
>
> if(ret == 0) {
> /* a solution is calculated, now lets get some results */
>
> /* objective value */
> System.out.println("Objective value: " + lp.getObjective());
>
> /* variable values */
> lp.getVariables(row);
> for(j = 0; j < Ncol; j++)
> System.out.println(lp.getColName(j + 1) + ": " + row[j]);
>
> /* we are done now */
> }
>
> /* clean up such that all used memory by lpsolve is freed */
> if(lp.getLp() != 0)
> lp.deleteLp();
>
> return(ret);
> }
>
> public static void main(String[] args) {
> try {
> //System.load("\\LpFiles\\lpsolve55j.dll");
> new Demo().execute();
> }
> catch (LpSolveException e) {
> e.printStackTrace();
> }
> }
> }
>
> i want this christ.LP has int declaration as,
>
> /* Objective function */
> max: +25 x +40 y;
>
> /* Constraints */
> +25 x <= 100;
> +40 y <= 80;
>
> /* Integer Definitions */
> int x,y;
>
> How can i?
>