Initializing help system before first use

XPRBsos

XPRBsos

Description
Methods for modifying and accessing Special Ordered Sets and operators for constructing them. Note that all members in a SOS must belong to the same problem as the SOS itself.
Constructors
XPRBsos();
XPRBsos(xbsos *s);
XPRBsos(xbsos *s, XPRBexpr& l);
Methods
int add(const XPRBexpr& le);
Add a linear expression to a SOS.
int addElement(XPRBvar& var, double val);
int addElement(double val, XPRBvar& var);
Add an element to a SOS.
int delElement(XPRBvar& var);
Delete an element from a SOS.
xbsos *getCRef();
Get the C modeling object.
const char *getName();
Get the name of a SOS.
int getType();
Get the type of a SOS.
bool isValid();
Test the validity of the SOS object.
int print();
Print out a SOS
int setDir(int type, double val);
int setDir(int type);
Set a branching directive for a SOS.
Operators
Assigning and adding linear expressions to Special Ordered Sets:
set = linexp
set += linexp

Constructor detail
XPRBsos
Synopsis
XPRBsos();
XPRBsos(xbsos *s);
XPRBsos(xbsos *s, XPRBexpr& l);
Arguments
s 
A SOS in BCL C.
l 
Linear expression defining the SOS.
Description
Create a new SOS object.
Method detail
add
Synopsis
int add(const XPRBexpr& le);
Argument
le 
A linear expression.
Return value
0 if method executed successfully, 1 otherwise.
Description
This method adds the variables of a linear expression to a SOS, using their coefficients in the linear expression as weights.
Example
This example shows different ways of defining SOS and modifying their contents. The resulting SOS definitions (as obtained with XPRBsos.print) and the output printed by the program are displayed as comments. 
XPRBvar x,y,z;
XPRBsos SO1, SO2;
XPRBprob prob("myprob");

x = prob.newVar("x", XPRB_PL, 0, 200);
y = prob.newVar("y", XPRB_PL, 0, 200);
z = prob.newVar("z", XPRB_PL, 0, 200);

SO1 = prob.newSos("SO1", XPRB_S1);
SO1.add(x+2*y+3*z);       // SO1(1): x(+1) y(+2) z(+3)
SO1 += 2*z-x;             // SO1(1): y(+2) z(+5)
cout << SO1.getName() << " type: ";
cout << (SO1.getType()==XPRB_S1?1:2) << endl;
                          // SO1 type: 1
SO2 = prob.newSos("SO2", XPRB_S2, 10*x+20*y);
SO2.addElement(z, 5);     // SO2(2): x(+10) y(+20) z(+5)
SO2.delElement(x);        // SO2(2): y(+20) z(+5)
addElement
Synopsis
int addElement(XPRBvar& var, double val);
int addElement(double val, XPRBvar& var);
Arguments
var 
Reference to a variable.
val 
The corresponding weight or reference value.
Return value
0 if function executed successfully, 1 otherwise
Description
This method adds a single 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.
Example
See XPRBsos.add.
Related topics
Calls XPRBaddsosel
delElement
Synopsis
int delElement(XPRBvar& var);
Argument
var 
A BCL variable.
Return value
0 if method executed successfully, 1 otherwise.
Description
This function removes a variable from a Special Ordered Set.
Example
See XPRBsos.add.
Related topics
Calls XPRBdelsosel
getCRef
Synopsis
xbsos *getCRef();
Return value
The underlying modeling object in BCL C.
Description
This method returns the SOS object in BCL C that belongs to the C++ SOS object.
getName
Synopsis
const char *getName();
Return value
Name of the SOS if executed successfully, NULL otherwise.
Description
This method returns the name of a SOS. If the user has not defined a name the default name generated by BCL is returned.
Example
See XPRBsos.add.
Related topics
Calls XPRBgetsosname
getType
Synopsis
int getType();
Return value
XPRB_S1 
a Special Ordered Set of type 1;
XPRB_S2 
a Special Ordered Set of type 2;
-1 
an error has occurred.
Description
This method returns the type of a SOS.
Example
See XPRBsos.add.
Related topics
Calls XPRBgetsostype
isValid
Synopsis
bool isValid();
Return value
true if object is valid, false otherwise.
Description
This method checks whether the SOS object is correctly defined. It should always be used to test the result returned by XPRBprob.getSosByName.
Example
See XPRBprob.getSosByName.
print
Synopsis
int print();
Return value
0 if function executed successfully, 1 otherwise.
Description
This method prints out a SOS. It is not available in the student version.
Example
See XPRBprob.getSosByName.
Related topics
Calls XPRBprintsos
setDir
Synopsis
int setDir(int type, double val);
int setDir(int type);
Arguments
type 
The directive type, which must be one of:
XPRB_PR 
priority;
XPRB_UP 
first branch upwards;
XPRB_DN 
first branch downwards;
XPRB_PU 
pseudo cost on branching upwards;
XPRB_PD 
pseudo cost on branching downwards.
val 
An argument dependent on the type of the directive being defined. If type is:
XPRB_PR 
val will be the priority value, an integer between 1 (highest) and 1000 (lowest), the default;
XPRB_UP 
no input is required;
XPRB_DN 
no input is required;
XPRB_PU 
val will be the value of the pseudo cost for the upward branch;
XPRB_PD 
val will be the value of the pseudo cost for the downward branch.
Return value
0 if method executed successfully, 1 otherwise.
Description
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_PD). Several directives of different types may be set for a single set. Method XPRBvar.setDir may be used to set a directive for a variable.
Example
See XPRBprob.clearDir.
Related topics
Calls XPRBsetsosdir

Parent Topic C++ class reference