Scippy

SCIP

Solving Constraint Integer Programs

Directed Graph

Detailed Description

Functions

SCIP_RETCODE SCIPdigraphCreate (SCIP_DIGRAPH **digraph, int nnodes)
 
SCIP_RETCODE SCIPdigraphResize (SCIP_DIGRAPH *digraph, int nnodes)
 
SCIP_RETCODE SCIPdigraphCopy (SCIP_DIGRAPH **targetdigraph, SCIP_DIGRAPH *sourcedigraph)
 
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)
 

Function Documentation

SCIP_RETCODE SCIPdigraphCreate ( SCIP_DIGRAPH **  digraph,
int  nnodes 
)

creates directed graph structure

Parameters
digraphpointer to store the created directed graph
nnodesnumber of nodes
SCIP_RETCODE SCIPdigraphResize ( SCIP_DIGRAPH digraph,
int  nnodes 
)

resize directed graph structure

Parameters
digraphdirected graph
nnodesnew number of nodes
SCIP_RETCODE SCIPdigraphCopy ( SCIP_DIGRAPH **  targetdigraph,
SCIP_DIGRAPH sourcedigraph 
)

copies directed graph structure

Note
The data in nodedata is copied verbatim. This possibly has to be adapted by the user.
Parameters
targetdigraphpointer to store the copied directed graph
sourcedigraphsource directed graph
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
digraphdirected graph
sizessizes of the successor lists
void SCIPdigraphFree ( SCIP_DIGRAPH **  digraph)

frees given directed graph structure

Parameters
digraphpointer to the directed graph
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
digraphdirected graph
startnodestart node of the arc
endnodestart node of the arc
datadata that should be stored for the arc; or NULL
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
digraphdirected graph
startnodestart node of the arc
endnodestart node of the arc
datadata that should be stored for the arc; or NULL
SCIP_RETCODE SCIPdigraphSetNSuccessors ( SCIP_DIGRAPH digraph,
int  node,
int  nsuccessors 
)

sets the number of successors to a given value

Parameters
digraphdirected graph
nodenode for which the number of successors has to be changed
nsuccessorsnew number of successors
int SCIPdigraphGetNNodes ( SCIP_DIGRAPH digraph)

returns the number of nodes of the given digraph

Parameters
digraphdirected graph
void* SCIPdigraphGetNodeData ( SCIP_DIGRAPH digraph,
int  node 
)

returns the node data, or NULL if no data exist

Parameters
digraphdirected graph
nodenode for which the node data is returned
void SCIPdigraphSetNodeData ( SCIP_DIGRAPH digraph,
void *  dataptr,
int  node 
)

sets the node data

Parameters
digraphdirected graph
dataptruser node data pointer, or NULL
nodenode for which the node data is returned
int SCIPdigraphGetNArcs ( SCIP_DIGRAPH digraph)

returns the total number of arcs in the given digraph

Parameters
digraphdirected graph
int SCIPdigraphGetNSuccessors ( SCIP_DIGRAPH digraph,
int  node 
)

returns the number of successor nodes of the given node

Parameters
digraphdirected graph
nodenode for which the number of outgoing arcs is returned
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
digraphdirected graph
nodenode for which the array of outgoing arcs is returned
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
digraphdirected graph
nodenode for which the data corresponding to the outgoing arcs is returned
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
digraphdirected graph
minsizeall components with less nodes are ignored
componentsarray 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()
ncomponentspointer to store the number of components; or NULL, if the number of components is accessed by SCIPdigraphGetNComponents()
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
digraphdirected graph
compidxnumber of the undirected connected component
strongcomponentsarray to store the strongly connected components (length >= size of the component)
strongcompstartidxarray to store the start indices of the strongly connected components (length >= size of the component)
nstrongcomponentspointer to store the number of strongly connected components
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.
Parameters
digraphdirected graph
int SCIPdigraphGetNComponents ( SCIP_DIGRAPH digraph)

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

Parameters
digraphdirected graph
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
digraphdirected graph
compidxnumber of the component to return
nodespointer to store the nodes in the component; or NULL, if not needed
nnodespointer to store the number of nodes in the component; or NULL, if not needed
void SCIPdigraphFreeComponents ( SCIP_DIGRAPH digraph)

frees the component information for the given directed graph

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

output of the given directed graph via the given message handler

Parameters
digraphdirected graph
messagehdlrmessage handler
fileoutput file (or NULL for standard output)
void SCIPdigraphPrintGml ( SCIP_DIGRAPH digraph,
FILE *  file 
)

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

Parameters
digraphdirected graph
filefile to write to
void SCIPdigraphPrintComponents ( SCIP_DIGRAPH digraph,
SCIP_MESSAGEHDLR messagehdlr,
FILE *  file 
)

output of the given directed graph via the given message handler

Parameters
digraphdirected graph
messagehdlrmessage handler
fileoutput file (or NULL for standard output)