com.dashoptimization

Class XPRBsos

java.lang.Object

com.dashoptimization.XPRBsos

public class XPRBsos
extends java.lang.Object

This class represents a Special Ordered Set (SOS) definition in BCL. All members in SOS must belong to the same problem as the SOS itself.

Method Summary

Modifier and Type	Method and Description
void	add(XPRBexpr l) Add a linear expression to a SOS.
void	addElement(double val, XPRBvar var)
void	addElement(XPRBvar var, double val) Add an element to a SOS.
void	assign(XPRBexpr l) Assign a linear expression to a SOS.
void	delElement(XPRBvar var) Delete an element from a SOS.
java.lang.String	getName() Get the name of a SOS.
int	getType() Get the type of a SOS.
boolean	isValid() Test whether a SOS is correctly defined.
void	print() Print out a Special Ordered Set.
void	setDir(int type)
void	setDir(int type, double val) Set a branching directive for a SOS.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

isValid

public boolean isValid()

Test whether a SOS is correctly defined.

     XPRBsos set1;
     if(set1.isValid() == false)
        System.out.println("Error in SOS definition.");
 

assign

public void assign(XPRBexpr l)
            throws java.lang.ArithmeticException

Assign a linear expression to a SOS.

     XPRBprob expl2;
     XPRBvar[] x;
     int i;
     XPRBexpr l;
     XPRBsos set3;
     expl2 = new XPRBprob("example2");
     for(i=0;i<5;i++) x[i] = expl2.newVar("x");
     l = new XPRBexpr();
     for(i=1;i<4;i++) l.add(x[i].mul(i));
     set3.assign(l);
 

Parameters:

l - linear expression

Throws:

java.lang.ArithmeticException

getName

public java.lang.String getName()

Get the name of a SOS. If the user has not defined a name the default name generated by BCL is returned.

     XPRBprob expl2;
     XPRBsos set1;
     expl2 = new XPRBprob("example2");
     set1 = expl2.newSos("sos1", XPRB.S1);
     System.out.println("SOS name:" + set1.getName());
 

Returns:

Name of the SOS if method executed successfully, null otherwise

getType

public int getType()

Get the type of a SOS.

     XPRBprob expl2;
     XPRBsos set1;
     int stype;
     expl2 = new XPRBprob("example2");
     set1 = expl2.newSos("sos1", XPRB.S1);
     stype = set1.getType();
 

Returns:

Type of the SOS. Possible values:

• XPRB.S1 Special Ordered Set of type 1
• XPRB.S2 Special Ordered Set of type 2
• -1 an error has occurred

setDir

public void setDir(int type,
                   double val)

Set a branching directive for a SOS. This method sets any type of branching directive available in Xpress. This may be a priority for branching on a SOS (type XPRB.PR), the preferred branching direction (types XPRB.UP, XPRB.DN) or the estimated cost incurred when branching on a SOS (types XPRB.PU, XPRB.PU). Several directives of different types may be set for a single set. Method XPRBvar.setDir(int, double) may be used to set a branching directive for a variable.

     XPRBprob expl2;
     XPRBsos set1;
     expl2 = new XPRBprob("example2");
     set1 = expl2.newSos("sos1", XPRB.S1);
     set1.setDir(XPRB.PR, 5);
     set1.setDir(XPRB.DN);
 

Parameters:

type - directive type. Possible values:

• XPRB.PR priority
• XPRB.UP first branch upwards
• XPRB.DN first branch downwards
• XPRB.PU pseudocost on branching upwards
• XPRB.PD pseudocost on branching downwards

val - the value of this argument depends on the type of directive to be defined. Possible values:

• XPRB.PR: priority value, integer between 1 (highest) and 1000 (least priority, default value)
• XPRB.UP,XPRB.DN: no input required, choose any dummy value (e.g. 0)
• XPRB.PU,XPRB.PD: value of pseudocost for the corresponding branch

setDir

public void setDir(int type)

See Also:

setDir(type, 0)

addElement

public void addElement(XPRBvar var,
                       double val)

Add an element to a SOS. This method adds a variable and its weight coefficient to a Special Ordered Set. If the variable is already contained in the set, the indicated value is added to its weight. Note that weight coefficients must be different from 0.

     XPRBprob expl2;
     XPRBsos set1;
     XPRBvar x2;
     expl2 = new XPRBprob("example2");
     x2 = expl2.newvar("abc1", XPRB.PL, 0, INFINITY);
     set1 = expl2.newSos("sos1", XPRB.S1);
     set1.addElement(x2, 9);
 

Parameters:

var - a variable of type XPRBvar

val - the corresponding weight or reference value

addElement

public void addElement(double val,
                       XPRBvar var)

See Also:

addElement(type, 0)

delElement

public void delElement(XPRBvar var)

Delete an element from a SOS.

     XPRBprob expl2;
     XPRBsos set1;
     XPRBvar x2;
     expl2 = new XPRBprob("example2");
     x2 = expl2.newvar("abc1", XPRB.PL, 0, INFINITY);
     set1 = expl2.newSos("sos1", XPRB.S1);
     set1.addElement(x2, 9);
     set1.delElement(x2);
 

Parameters:

var - a variable of type XPRBvar

add

public void add(XPRBexpr l)
         throws java.lang.ArithmeticException

Add a linear expression to a SOS. If a variable in the linear expression is already contained in the set, the indicated value is added to its weight. Constant terms in the linear expression are ignored.

     XPRBprob expl2;
     XPRBvar[] x;
     int i;
     XPRBexpr l;
     XPRBsos set3;
     expl2 = new XPRBprob("example2");
     for(i=0;i<5;i++) x[i] = expl2.newVar("x");
     l = new XPRBexpr();
     for(i=1;i<4;i++) l.add(x[i].mul(i));
     set3 = expl2.newSos("sos2", XPRB.S2);
     set3.add(l);
 

Parameters:

l - linear expression

Throws:

java.lang.ArithmeticException

print

public void print()

Print out a Special Ordered Set. This method is not available in the Student Edition.

     XPRBprob expl2;
     XPRBsos set1;
     expl2 = new XPRBprob("example2");
     set1 = expl2.newSos("sos1", XPRB.S1);
     set1.print();
 

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

getName()