Directed Graph

Detailed Description

graph structure with common algorithms for directed and undirected graphs

Functions
SCIP_RETCODE	SCIPdigraphResize (SCIP_DIGRAPH *digraph, int nnodes)
SCIP_RETCODE	SCIPdigraphSetSizes (SCIP_DIGRAPH *digraph, int *sizes)
void	SCIPdigraphFree (SCIP_DIGRAPH **digraph)
SCIP_RETCODE	SCIPdigraphAddArc (SCIP_DIGRAPH *digraph, int startnode, int endnode, void *data)
SCIP_RETCODE	SCIPdigraphAddArcSafe (SCIP_DIGRAPH *digraph, int startnode, int endnode, void *data)
SCIP_RETCODE	SCIPdigraphSetNSuccessors (SCIP_DIGRAPH *digraph, int node, int nsuccessors)
int	SCIPdigraphGetNNodes (SCIP_DIGRAPH *digraph)
void *	SCIPdigraphGetNodeData (SCIP_DIGRAPH *digraph, int node)
void	SCIPdigraphSetNodeData (SCIP_DIGRAPH *digraph, void *dataptr, int node)
int	SCIPdigraphGetNArcs (SCIP_DIGRAPH *digraph)
int	SCIPdigraphGetNSuccessors (SCIP_DIGRAPH *digraph, int node)
int *	SCIPdigraphGetSuccessors (SCIP_DIGRAPH *digraph, int node)
void **	SCIPdigraphGetSuccessorsData (SCIP_DIGRAPH *digraph, int node)
SCIP_RETCODE	SCIPdigraphComputeUndirectedComponents (SCIP_DIGRAPH *digraph, int minsize, int *components, int *ncomponents)
SCIP_RETCODE	SCIPdigraphComputeDirectedComponents (SCIP_DIGRAPH *digraph, int compidx, int *strongcomponents, int *strongcompstartidx, int *nstrongcomponents)
SCIP_RETCODE	SCIPdigraphTopoSortComponents (SCIP_DIGRAPH *digraph)
int	SCIPdigraphGetNComponents (SCIP_DIGRAPH *digraph)
void	SCIPdigraphGetComponent (SCIP_DIGRAPH *digraph, int compidx, int **nodes, int *nnodes)
void	SCIPdigraphFreeComponents (SCIP_DIGRAPH *digraph)
void	SCIPdigraphPrint (SCIP_DIGRAPH *digraph, SCIP_MESSAGEHDLR *messagehdlr, FILE *file)
void	SCIPdigraphPrintGml (SCIP_DIGRAPH *digraph, FILE *file)
void	SCIPdigraphPrintComponents (SCIP_DIGRAPH *digraph, SCIP_MESSAGEHDLR *messagehdlr, FILE *file)
SCIP_RETCODE	SCIPcreateDigraph (SCIP *scip, SCIP_DIGRAPH **digraph, int nnodes)
SCIP_RETCODE	SCIPcopyDigraph (SCIP *scip, SCIP_DIGRAPH **targetdigraph, SCIP_DIGRAPH *sourcedigraph)

Function Documentation

SCIPdigraphResize()

SCIP_RETCODE SCIPdigraphResize	(	SCIP_DIGRAPH *	digraph,
		int	nnodes
	)

resize directed graph structure

Parameters

digraph	directed graph
nnodes	new number of nodes

Definition at line 6926 of file misc.c.

References SCIP_Digraph::arcdata, SCIP_Digraph::blkmem, BMSreallocBlockMemoryArray, nnodes, SCIP_Digraph::nnodes, SCIP_Digraph::nodedata, SCIP_Digraph::nsuccessors, SCIP_ALLOC, SCIP_OKAY, SCIP_Digraph::successors, and SCIP_Digraph::successorssize.

Referenced by SCIPrealHashCode().

SCIPdigraphSetSizes()

SCIP_RETCODE SCIPdigraphSetSizes	(	SCIP_DIGRAPH *	digraph,
		int *	sizes
	)

sets the sizes of the successor lists for the nodes in a directed graph and allocates memory for the lists

Parameters

digraph	directed graph
sizes	sizes of the successor lists

Definition at line 7040 of file misc.c.

References SCIP_Digraph::arcdata, SCIP_Digraph::blkmem, BMSallocBlockMemoryArray, SCIP_Digraph::nnodes, SCIP_Digraph::nsuccessors, SCIP_ALLOC, SCIP_OKAY, SCIP_Digraph::successors, and SCIP_Digraph::successorssize.

Referenced by findComponents(), and SCIPrealHashCode().

SCIPdigraphFree()

void SCIPdigraphFree

(

SCIP_DIGRAPH **

digraph

)

frees given directed graph structure

Parameters

digraph

pointer to the directed graph

Definition at line 7064 of file misc.c.

References SCIP_Digraph::arcdata, BMSfreeBlockMemory, BMSfreeBlockMemoryArray, BMSfreeBlockMemoryArrayNull, SCIP_Digraph::components, SCIP_Digraph::componentstarts, SCIP_Digraph::componentstartsize, SCIP_Digraph::ncomponents, SCIP_Digraph::nnodes, SCIP_Digraph::nodedata, SCIP_Digraph::nsuccessors, SCIPdigraphFreeComponents(), SCIP_Digraph::successors, and SCIP_Digraph::successorssize.

Referenced by findComponents(), freeConflictgraph(), presolRoundConssSOS1(), presolRoundVarsSOS1(), SCIPrealHashCode(), sortGenVBounds(), and tightenVarsBoundsSOS1().

SCIPdigraphAddArc()

SCIP_RETCODE SCIPdigraphAddArc	(	SCIP_DIGRAPH *	digraph,
		int	startnode,
		int	endnode,
		void *	data
	)

add (directed) arc and a related data to the directed graph structure

Note

if the arc is already contained, it is added a second time

Parameters

digraph	directed graph
startnode	start node of the arc
endnode	start node of the arc
data	data that should be stored for the arc; or NULL

Definition at line 7154 of file misc.c.

References SCIP_Digraph::arcdata, ensureSuccessorsSize(), nnodes, SCIP_Digraph::nsuccessors, SCIP_CALL, SCIP_OKAY, and SCIP_Digraph::successors.

Referenced by addBranchingComplementaritiesSOS1(), fillDigraph(), SCIPdigraphComputeUndirectedComponents(), SCIPrealHashCode(), sortGenVBounds(), and updateArcData().

SCIPdigraphAddArcSafe()

SCIP_RETCODE SCIPdigraphAddArcSafe	(	SCIP_DIGRAPH *	digraph,
		int	startnode,
		int	endnode,
		void *	data
	)

add (directed) arc to the directed graph structure, if it is not contained, yet

Note

if there already exists an arc from startnode to endnode, the new arc is not added, even if its data is different

Parameters

digraph	directed graph
startnode	start node of the arc
endnode	start node of the arc
data	data that should be stored for the arc; or NULL

Definition at line 7182 of file misc.c.

References SCIP_Digraph::arcdata, ensureSuccessorsSize(), nnodes, SCIP_Digraph::nsuccessors, SCIP_CALL, SCIP_OKAY, and SCIP_Digraph::successors.

Referenced by enforceConflictgraph(), extensionOperatorSOS1(), genConflictgraphLinearCons(), handleNewVariableSOS1(), initConflictgraph(), performImplicationGraphAnalysis(), presolRoundConssSOS1(), and SCIPrealHashCode().

SCIPdigraphSetNSuccessors()

SCIP_RETCODE SCIPdigraphSetNSuccessors	(	SCIP_DIGRAPH *	digraph,
		int	node,
		int	nsuccessors
	)

sets the number of successors to a given value

Parameters

digraph	directed graph
node	node for which the number of successors has to be changed
nsuccessors	new number of successors

Definition at line 7216 of file misc.c.

References nnodes, SCIP_Digraph::nsuccessors, and SCIP_OKAY.

Referenced by resetConflictgraphSOS1(), and SCIPrealHashCode().

SCIPdigraphGetNNodes()

int SCIPdigraphGetNNodes

(

SCIP_DIGRAPH *

digraph

)

returns the number of nodes of the given digraph

Parameters

digraph

directed graph

Definition at line 7232 of file misc.c.

References SCIP_Digraph::nnodes.

Referenced by cliqueGetCommonSuccessorsSOS1(), nodeGetSolvalBinaryBigMSOS1(), nodeGetSolvalVarboundLbSOS1(), nodeGetSolvalVarboundUbSOS1(), performImplicationGraphAnalysis(), SCIPrealHashCode(), and sortGenVBounds().

SCIPdigraphGetNodeData()

void* SCIPdigraphGetNodeData	(	SCIP_DIGRAPH *	digraph,
		int	node
	)

returns the node data, or NULL if no data exist

Parameters

digraph	directed graph
node	node for which the node data is returned

Definition at line 7242 of file misc.c.

References nnodes, and SCIP_Digraph::nodedata.

Referenced by addBranchingComplementaritiesSOS1(), checkConComponentsVarbound(), detectVarboundSOS1(), freeConflictgraph(), generateBoundInequalityFromSOS1Nodes(), getBoundConsFromVertices(), nodeGetSolvalVarboundLbSOS1(), nodeGetSolvalVarboundUbSOS1(), passConComponentVarbound(), propVariableNonzero(), SCIPrealHashCode(), and sepaImplBoundCutsSOS1().

SCIPdigraphSetNodeData()

void SCIPdigraphSetNodeData	(	SCIP_DIGRAPH *	digraph,
		void *	dataptr,
		int	node
	)

sets the node data

sets the node data

Note

The old user pointer is not freed. This has to be done by the user

Parameters

digraph	directed graph
dataptr	user node data pointer, or NULL
node	node for which the node data is returned

Definition at line 7258 of file misc.c.

References nnodes, and SCIP_Digraph::nodedata.

Referenced by freeConflictgraph(), initConflictgraph(), initImplGraphSOS1(), and SCIPrealHashCode().

SCIPdigraphGetNArcs()

int SCIPdigraphGetNArcs

(

SCIP_DIGRAPH *

digraph

)

returns the total number of arcs in the given digraph

Parameters

digraph

directed graph

Definition at line 7272 of file misc.c.

References narcs, SCIP_Digraph::nnodes, and SCIP_Digraph::nsuccessors.

Referenced by SCIP_DECL_SEPAEXECLP(), SCIPrealHashCode(), and sepaImplBoundCutsSOS1().

SCIPdigraphGetNSuccessors()

int SCIPdigraphGetNSuccessors	(	SCIP_DIGRAPH *	digraph,
		int	node
	)

returns the number of successor nodes of the given node

Parameters

digraph	directed graph
node	node for which the number of outgoing arcs is returned

Definition at line 7290 of file misc.c.

References nnodes, SCIP_Digraph::nsuccessors, and SCIP_Digraph::successorssize.

Referenced by addBranchingComplementaritiesSOS1(), checkConComponentsVarbound(), checkSwitchNonoverlappingSOS1Methods(), cliqueGetCommonSuccessorsSOS1(), computeVarsCoverSOS1(), enforceConflictgraph(), genConflictgraphLinearCons(), getBoundConsFromVertices(), getBranchingPrioritiesSOS1(), getBranchingVerticesSOS1(), getCoverVertices(), getDiveBdChgsSOS1conflictgraph(), getSOS1Implications(), getVectorOfWeights(), handleNewVariableSOS1(), initConflictgraph(), initImplGraphSOS1(), initTCliquegraph(), isConnectedSOS1(), isViolatedSOS1(), markNeighborsMWISHeuristic(), maxWeightIndSetHeuristic(), passConComponentVarbound(), performImplicationGraphAnalysis(), presolRoundConssSOS1(), presolRoundVarsSOS1(), propVariableNonzero(), resetConflictgraphSOS1(), SCIP_DECL_SEPAEXECLP(), SCIPrealHashCode(), sepaImplBoundCutsSOS1(), tightenVarsBoundsSOS1(), and updateArcData().

SCIPdigraphGetSuccessors()

int* SCIPdigraphGetSuccessors	(	SCIP_DIGRAPH *	digraph,
		int	node
	)

returns the array of indices of the successor nodes; this array must not be changed from outside

Parameters

digraph	directed graph
node	node for which the array of outgoing arcs is returned

Definition at line 7305 of file misc.c.

References nnodes, SCIP_Digraph::nsuccessors, SCIP_Digraph::successors, and SCIP_Digraph::successorssize.

Referenced by addBranchingComplementaritiesSOS1(), checkConComponentsVarbound(), cliqueGetCommonSuccessorsSOS1(), computeVarsCoverSOS1(), enforceConflictgraph(), genConflictgraphLinearCons(), getBoundConsFromVertices(), getBranchingVerticesSOS1(), getCoverVertices(), getDiveBdChgsSOS1conflictgraph(), getSOS1Implications(), getVectorOfWeights(), handleNewVariableSOS1(), initConflictgraph(), initImplGraphSOS1(), initTCliquegraph(), isConnectedSOS1(), isViolatedSOS1(), markNeighborsMWISHeuristic(), passConComponentVarbound(), performImplicationGraphAnalysis(), presolRoundConssSOS1(), propVariableNonzero(), resetConflictgraphSOS1(), SCIP_DECL_SEPAEXECLP(), SCIPrealHashCode(), sepaImplBoundCutsSOS1(), tightenVarsBoundsSOS1(), and updateArcData().

SCIPdigraphGetSuccessorsData()

void** SCIPdigraphGetSuccessorsData	(	SCIP_DIGRAPH *	digraph,
		int	node
	)

returns the array of data corresponding to the arcs originating at the given node, or NULL if no data exist; this array must not be changed from outside

Parameters

digraph	directed graph
node	node for which the data corresponding to the outgoing arcs is returned

Definition at line 7323 of file misc.c.

References SCIP_Digraph::arcdata, nnodes, SCIP_Digraph::nsuccessors, and SCIP_Digraph::successorssize.

Referenced by getSOS1Implications(), performImplicationGraphAnalysis(), presolRoundVarsSOS1(), propVariableNonzero(), SCIPrealHashCode(), sepaImplBoundCutsSOS1(), and updateArcData().

SCIPdigraphComputeUndirectedComponents()

SCIP_RETCODE SCIPdigraphComputeUndirectedComponents	(	SCIP_DIGRAPH *	digraph,
		int	minsize,
		int *	components,
		int *	ncomponents
	)

Compute undirected connected components on the given graph.

Note

For each arc, its reverse is added, so the graph does not need to be the directed representation of an undirected graph.

Parameters

digraph	directed graph
minsize	all components with less nodes are ignored
components	array with as many slots as there are nodes in the directed graph to store for each node the component to which it belongs (components are numbered 0 to ncomponents - 1); or NULL, if components are accessed one-by-one using SCIPdigraphGetComponent()
ncomponents	pointer to store the number of components; or NULL, if the number of components is accessed by SCIPdigraphGetNComponents()

Definition at line 7417 of file misc.c.

References SCIP_Digraph::blkmem, BMSallocBlockMemoryArray, BMSallocClearMemoryArray, BMSallocMemoryArray, BMSclearMemoryArray, BMScopyMemoryArray, BMSfreeMemoryArrayNull, BMSreallocBlockMemoryArray, SCIP_Digraph::components, SCIP_Digraph::componentstarts, SCIP_Digraph::componentstartsize, depthFirstSearch(), SCIP_Digraph::ncomponents, SCIP_Digraph::nnodes, SCIP_Digraph::nsuccessors, SCIP_ALLOC, SCIP_ALLOC_TERMINATE, SCIP_Bool, SCIP_CALL_TERMINATE, SCIP_OKAY, SCIPdigraphAddArc(), SCIPdigraphFreeComponents(), and SCIP_Digraph::successors.

Referenced by findComponents(), SCIPrealHashCode(), and sortGenVBounds().

SCIPdigraphComputeDirectedComponents()

SCIP_RETCODE SCIPdigraphComputeDirectedComponents	(	SCIP_DIGRAPH *	digraph,
		int	compidx,
		int *	strongcomponents,
		int *	strongcompstartidx,
		int *	nstrongcomponents
	)

Computes all strongly connected components of an undirected connected component with Tarjan's Algorithm. The resulting strongly connected components are sorted topologically (starting from the end of the strongcomponents array).

Note

In general a topological sort of the strongly connected components is not unique.

Parameters

digraph	directed graph
compidx	number of the undirected connected component
strongcomponents	array to store the strongly connected components (length >= size of the component)
strongcompstartidx	array to store the start indices of the strongly connected components (length >= size of the component)
nstrongcomponents	pointer to store the number of strongly connected components

Definition at line 7757 of file misc.c.

References BMSallocMemoryArray, BMSfreeMemoryArrayNull, SCIP_Digraph::components, SCIP_Digraph::componentstarts, FALSE, nnodes, SCIP_Digraph::nnodes, SCIP_ALLOC_TERMINATE, SCIP_Bool, SCIP_OKAY, SCIPdebugMessage, tarjan(), and TRUE.

Referenced by SCIPrealHashCode(), and sortGenVBounds().

SCIPdigraphTopoSortComponents()

SCIP_RETCODE SCIPdigraphTopoSortComponents

(

SCIP_DIGRAPH *

digraph

)

Performes an (almost) topological sort on the undirected components of the given directed graph. The undirected components should be computed before using SCIPdigraphComputeUndirectedComponents().

Note

In general a topological sort is not unique. Note, that there might be directed cycles, that are randomly broken, which is the reason for having only almost topologically sorted arrays.

Performs an (almost) topological sort on the undirected components of the given directed graph. The undirected components should be computed before using SCIPdigraphComputeUndirectedComponents().

Note

In general a topological sort is not unique. Note, that there might be directed cycles, that are randomly broken, which is the reason for having only almost topologically sorted arrays.

Parameters

digraph

directed graph

Definition at line 7546 of file misc.c.

References BMSallocClearMemoryArray, BMSallocMemoryArray, BMSfreeMemoryArrayNull, SCIP_Digraph::components, SCIP_Digraph::componentstarts, depthFirstSearch(), SCIP_Digraph::ncomponents, SCIP_Digraph::nnodes, SCIP_ALLOC_TERMINATE, SCIP_Bool, and SCIP_OKAY.

Referenced by SCIPrealHashCode(), and sortGenVBounds().

SCIPdigraphGetNComponents()

int SCIPdigraphGetNComponents

(

SCIP_DIGRAPH *

digraph

)

returns the number of previously computed undirected components for the given directed graph

Parameters

digraph

directed graph

Definition at line 7612 of file misc.c.

References SCIP_Digraph::componentstartsize, and SCIP_Digraph::ncomponents.

Referenced by SCIPrealHashCode(), sortComponents(), and sortGenVBounds().

SCIPdigraphGetComponent()

void SCIPdigraphGetComponent	(	SCIP_DIGRAPH *	digraph,
		int	compidx,
		int **	nodes,
		int *	nnodes
	)

Returns the previously computed undirected component of the given number for the given directed graph. If the components were sorted using SCIPdigraphTopoSortComponents(), the component is (almost) topologically sorted.

Parameters

digraph	directed graph
compidx	number of the component to return
nodes	pointer to store the nodes in the component; or NULL, if not needed
nnodes	pointer to store the number of nodes in the component; or NULL, if not needed

Definition at line 7625 of file misc.c.

References SCIP_Digraph::components, and SCIP_Digraph::componentstarts.

Referenced by SCIPrealHashCode(), sortComponents(), and sortGenVBounds().

SCIPdigraphFreeComponents()

void SCIPdigraphFreeComponents

(

SCIP_DIGRAPH *

digraph

)

frees the component information for the given directed graph

Parameters

digraph

directed graph

Definition at line 7845 of file misc.c.

References SCIP_Digraph::blkmem, BMSfreeBlockMemoryArray, SCIP_Digraph::components, SCIP_Digraph::componentstarts, SCIP_Digraph::componentstartsize, SCIP_Digraph::ncomponents, and SCIP_Digraph::nnodes.

Referenced by SCIPdigraphComputeUndirectedComponents(), SCIPdigraphFree(), and SCIPrealHashCode().

SCIPdigraphPrint()

void SCIPdigraphPrint	(	SCIP_DIGRAPH *	digraph,
		SCIP_MESSAGEHDLR *	messagehdlr,
		FILE *	file
	)

output of the given directed graph via the given message handler

Parameters

digraph	directed graph
messagehdlr	message handler
file	output file (or NULL for standard output)

Definition at line 7877 of file misc.c.

References SCIP_Digraph::nnodes, SCIP_Digraph::nsuccessors, SCIPmessageFPrintInfo(), and SCIP_Digraph::successors.

Referenced by SCIPrealHashCode().

SCIPdigraphPrintGml()

void SCIPdigraphPrintGml	(	SCIP_DIGRAPH *	digraph,
		FILE *	file
	)

prints the given directed graph structure in GML format into the given file

Parameters

digraph	directed graph
file	file to write to

Definition at line 7912 of file misc.c.

References SCIP_Digraph::nnodes, SCIP_Digraph::nsuccessors, SCIP_MAXSTRLEN, SCIPgmlWriteArc(), SCIPgmlWriteClosing(), SCIPgmlWriteNode(), SCIPgmlWriteOpening(), SCIPsnprintf(), SCIP_Digraph::successors, and TRUE.

Referenced by SCIPrealHashCode().

SCIPdigraphPrintComponents()

void SCIPdigraphPrintComponents	(	SCIP_DIGRAPH *	digraph,
		SCIP_MESSAGEHDLR *	messagehdlr,
		FILE *	file
	)

output of the given directed graph via the given message handler

Parameters

digraph	directed graph
messagehdlr	message handler
file	output file (or NULL for standard output)

Definition at line 7951 of file misc.c.

References SCIP_Digraph::components, SCIP_Digraph::componentstarts, SCIP_Digraph::ncomponents, and SCIPmessageFPrintInfo().

Referenced by SCIPrealHashCode().

SCIPcreateDigraph()

SCIP_RETCODE SCIPcreateDigraph	(	SCIP *	scip,
		SCIP_DIGRAPH **	digraph,
		int	nnodes
	)

creates directed graph structure

Parameters

scip	SCIP data structure
digraph	pointer to store the created directed graph
nnodes	number of nodes

Definition at line 48568 of file scip.c.

References Scip::mem, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, and SCIPdigraphCreate().

Referenced by findComponents(), presolRoundConssSOS1(), presolRoundVarsSOS1(), sortGenVBounds(), and tightenVarsBoundsSOS1().

SCIPcopyDigraph()

SCIP_RETCODE SCIPcopyDigraph	(	SCIP *	scip,
		SCIP_DIGRAPH **	targetdigraph,
		SCIP_DIGRAPH *	sourcedigraph
	)

copies directed graph structure

The copying procedure uses the memory of the passed SCIP instance. The user must ensure that the digraph lives as most as long as the SCIP instance.

Note

The data in nodedata is copied verbatim. This possibly has to be adapted by the user.

Parameters

scip	SCIP data structure
targetdigraph	pointer to store the copied directed graph
sourcedigraph	source directed graph

Definition at line 48589 of file scip.c.

References Scip::mem, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, and SCIPdigraphCopy().