SbbNodeInfo Class Reference

#include <SbbNode.hpp>

Inheritance diagram for SbbNodeInfo:

List of all members.

Public Member Functions
virtual void	applyToModel (SbbModel *model, CoinWarmStartBasis *&basis, SbbCountRowCut **addCuts, int &currentNumberCuts) const=0
	Modify model according to information at node.
virtual SbbNodeInfo *	buildRowBasis (CoinWarmStartBasis &basis) const=0
virtual SbbNodeInfo *	clone () const=0
	Clone.
void	increment (int amount=1)
	Increment number of references.
int	decrement (int amount=1)
	Decrement number of references and return number left.
void	initializeInfo (int number)
int	numberBranchesLeft () const
	Return number of branches left in object.
int	numberPointingToThis () const
	Return number of objects pointing to this.
int	branchedOn ()
	Say one branch taken.
void	throwAway ()
	Say thrown away.
SbbNodeInfo *	parent () const
	Parent of this.
void	addCuts (OsiCuts &cuts, int numberToBranch, int *whichGenerator)
void	addCuts (int numberCuts, SbbCountRowCut **cuts, int numberToBranch)
void	deleteCuts (int numberToDelete, SbbCountRowCut **cuts)
void	deleteCuts (int numberToDelete, int *which)
void	deleteCut (int whichOne)
	Really delete a cut.
void	decrementCuts (int change=1)
	Decrement active cut counts.
void	decrementParentCuts (int change=1)
	Decrement all active cut counts in chain starting at parent.
void	incrementParentCuts (int change=1)
	Increment all active cut counts in parent chain.
SbbCountRowCut **	cuts () const
	Array of pointers to cuts.
int	numberCuts () const
	Number of row cuts (this node).
void	setNumberCuts (int value)
void	nullOwner ()
	Set owner null.
Constructors & destructors
	SbbNodeInfo ()
	SbbNodeInfo (SbbNodeInfo *parent)
	SbbNodeInfo (SbbNodeInfo *parent, SbbNode *owner)
virtual	~SbbNodeInfo ()
Protected Attributes
int	numberPointingToThis_
SbbNodeInfo *	parent_
	parent
SbbNode *	owner_
	Owner.
int	numberCuts_
	Number of row cuts (this node).
SbbCountRowCut **	cuts_
	Array of pointers to cuts.
int	numberRows_
int	numberBranchesLeft_
Private Member Functions
SbbNodeInfo &	operator= (const SbbNodeInfo &rhs)
	Illegal Assignment operator.

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Detailed Description

Information required to recreate the subproblem at this node

When a subproblem is initially created, it is represented by an SbbNode object and an attached SbbNodeInfo object.

The SbbNode contains information needed while the subproblem remains live. The SbbNode is deleted when the last branch arm has been evaluated.

The SbbNodeInfo contains information required to maintain the branch-and-cut search tree structure (links and reference counts) and to recreate the subproblem for this node (basis, variable bounds, cutting planes). An SbbNodeInfo object remains in existence until all nodes have been pruned from the subtree rooted at this node.

The principle used to maintain the reference count is that the reference count is always the sum of all potential and actual children of the node. Specifically,

• Once it's determined how the node will branch, the reference count is set to the number of potential children (i.e., the number of arms of the branch).
• As each child is created by SbbNode::branch() (converting a potential child to the active subproblem), the reference count is decremented.
• If the child survives and will become a node in the search tree (converting the active subproblem into an actual child), increment the reference count.

Notice that the active subproblem lives in a sort of limbo, neither a potential or an actual node in the branch-and-cut tree.

SbbNodeInfo objects come in two flavours. An SbbFullNodeInfo object contains a full record of the information required to recreate a subproblem. An SbbPartialNodeInfo object expresses this information in terms of differences from the parent.

Definition at line 59 of file SbbNode.hpp.

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Constructor & Destructor Documentation

SbbNodeInfo::SbbNodeInfo (   )

Default Constructor Creates an empty NodeInfo object. Definition at line 27 of file SbbNode.cpp. 00028 : 00029 numberPointingToThis_(0), 00030 parent_(NULL), 00031 owner_(NULL), 00032 numberCuts_(0), 00033 cuts_(NULL), 00034 numberRows_(0), 00035 numberBranchesLeft_(0) 00036 { 00037 #ifdef CHECK_NODE 00038 printf("SbbNodeInfo %x Constructor\n",this); 00039 #endif 00040 } // Constructor given parent

SbbNodeInfo::SbbNodeInfo (  SbbNodeInfo *  parent  )

Construct with parent Creates a NodeInfo object which knows its parent and assumes it will in turn have two children. Definition at line 42 of file SbbNode.cpp. References numberCuts_, numberRows_, and parent_. 00043 : 00044 numberPointingToThis_(2), 00045 parent_(parent), 00046 owner_(NULL), 00047 numberCuts_(0), 00048 cuts_(NULL), 00049 numberRows_(0), 00050 numberBranchesLeft_(2) 00051 { 00052 #ifdef CHECK_NODE 00053 printf("SbbNodeInfo %x Constructor from parent %x\n",this,parent_); 00054 #endif 00055 if (parent_) { 00056 numberRows_ = parent_->numberRows_+parent_->numberCuts_; 00057 } 00058 } // Constructor given parent and owner

SbbNodeInfo::SbbNodeInfo (  SbbNodeInfo *  parent, SbbNode *  owner )

Construct with parent and owner As for `construct with parent', and attached to owner. Definition at line 60 of file SbbNode.cpp. References numberCuts_, numberRows_, and parent_. : numberPointingToThis_(2), parent_(parent), owner_(owner), numberCuts_(0), cuts_(NULL), numberRows_(0), numberBranchesLeft_(2) { #ifdef CHECK_NODE printf("SbbNodeInfo %x Constructor from parent %x\n",this,parent_); #endif if (parent_) { numberRows_ = parent_->numberRows_+parent_->numberCuts_; } }

SbbNodeInfo::~SbbNodeInfo (   )  [virtual]

Destructor Note that the destructor will recursively delete the parent if this nodeInfo is the last child. Definition at line 83 of file SbbNode.cpp. References cuts_, decrement(), SbbNode::nullNodeInfo(), numberPointingToThis_, owner_, and parent_. { #ifdef CHECK_NODE printf("SbbNodeInfo %x Destructor parent %x\n",this,parent_); #endif assert(!numberPointingToThis_); delete [] cuts_; if (owner_) owner_->nullNodeInfo(); if (parent_) { int numberLinks = parent_->decrement(); if (!numberLinks) delete parent_; } }

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Member Function Documentation

virtual void SbbNodeInfo::applyToModel (  SbbModel *  model, CoinWarmStartBasis *&  basis, SbbCountRowCut **  addCuts, int &  currentNumberCuts )  const [pure virtual]

Modify model according to information at node. The routine modifies the model according to bound and basis information at node and adds any cuts to the addCuts array. Implemented in SbbFullNodeInfo, and SbbPartialNodeInfo. Referenced by SbbModel::addCuts1().

virtual SbbNodeInfo* SbbNodeInfo::buildRowBasis (  CoinWarmStartBasis &  basis  )  const [pure virtual]

Builds up row basis backwards (until original model). Returns NULL or previous one to apply . Depends on Free being 0 and impossible for cuts Implemented in SbbFullNodeInfo, and SbbPartialNodeInfo. Referenced by decrementParentCuts(), and incrementParentCuts().

void SbbNodeInfo::deleteCuts (  int  numberToDelete, SbbCountRowCut **  cuts )

Delete cuts (decrements counts) Slow unless cuts in same order as saved Definition at line 299 of file SbbNode.cpp. References cuts_, SbbCountRowCut::decrement(), and numberCuts_. { int i; int j; int last=-1; for (i=0;i<numberToDelete;i++) { SbbCountRowCut * next = cuts[i]; for (j=last+1;j<numberCuts_;j++) { if (next==cuts_[j]) break; } if (j==numberCuts_) { // start from beginning for (j=0;j<last;j++) { if (next==cuts_[j]) break; } assert(j<last); } last=j; int number = cuts_[j]->decrement(); if (!number) delete cuts_[j]; cuts_[j]=NULL; } j=0; for (i=0;i<numberCuts_;i++) { if (cuts_[i]) cuts_[j++]=cuts_[i]; } numberCuts_ = j; }

void SbbNodeInfo::initializeInfo (  int  number  )  [inline]

Initialize reference counts Initialize the reference counts used for tree maintenance. Definition at line 123 of file SbbNode.hpp. References numberBranchesLeft_, and numberPointingToThis_. Referenced by SbbNode::initializeInfo(). {numberPointingToThis_=number;numberBranchesLeft_=number;};

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Member Data Documentation

int SbbNodeInfo::numberBranchesLeft_ [protected]

Number of branch arms left to explore at this node Todo: There seems to be redundancy between this field and SbbBranchingObject::numberBranchesLeft_. It'd be good to sort out if both are necessary. Definition at line 212 of file SbbNode.hpp. Referenced by branchedOn(), decrementCuts(), decrementParentCuts(), initializeInfo(), numberBranchesLeft(), and throwAway().

int SbbNodeInfo::numberPointingToThis_ [protected]

Number of other nodes pointing to this node. Number of existing and potential search tree nodes pointing to this node. `Existing' means referenced by parent_ of some other SbbNodeInfo. `Potential' means children still to be created (numberBranchesLeft_ of this SbbNodeInfo). Definition at line 188 of file SbbNode.hpp. Referenced by branchedOn(), decrement(), increment(), initializeInfo(), numberPointingToThis(), throwAway(), and ~SbbNodeInfo().

int SbbNodeInfo::numberRows_ [protected]

Number of rows in problem (before these cuts). This means that for top of chain it must be rows at continuous Definition at line 204 of file SbbNode.hpp. Referenced by decrementParentCuts(), incrementParentCuts(), and SbbNodeInfo().

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The documentation for this class was generated from the following files:

• SbbNode.hpp
• SbbNode.cpp

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