GRASS GIS 8 Programmer's Manual
8.4.0dev(2024)c17eaff561

Network Analysis library  flow in graph. More...
#include <stdio.h>
#include <stdlib.h>
#include <grass/gis.h>
#include <grass/vector.h>
#include <grass/glocale.h>
#include <grass/dgl/graph.h>
#include <grass/neta.h>
Go to the source code of this file.
Functions  
dglInt32_t  sign (dglInt32_t x) 
int  NetA_flow (dglGraph_s *graph, struct ilist *source_list, struct ilist *sink_list, int *flow) 
Get max flow from source to sink. More...  
int  NetA_min_cut (dglGraph_s *graph, struct ilist *source_list, struct ilist *sink_list UNUSED, int *flow, struct ilist *cut) 
Calculates minimum cut between source(s) and sink(s). More...  
int  NetA_split_vertices (dglGraph_s *in, dglGraph_s *out, int *node_costs) 
Splits each vertex of in graph into two vertices. More...  
Network Analysis library  flow in graph.
Computes the length of the shortest path between all pairs of nodes in the network.
(C) 20092010 by Daniel Bundala, and the GRASS Development Team
This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.
Definition in file flow.c.
int NetA_flow  (  dglGraph_s *  graph, 
struct ilist *  source_list,  
struct ilist *  sink_list,  
int *  flow  
) 
Get max flow from source to sink.
Array flow stores flow for each edge. Negative flow corresponds to a flow in opposite direction. The function assumes that the edge costs correspond to edge capacities.
graph  input graph  
source_list  list of sources  
sink_list  list of sinks  
[out]  flow  max flows 
Definition at line 47 of file flow.c.
References _, dglGet_EdgeCount(), dglGet_NodeAttrSize(), dglGet_NodeCount(), G_calloc, G_fatal_error(), ilist::n_values, NULL, and ilist::value.
int NetA_min_cut  (  dglGraph_s *  graph, 
struct ilist *  source_list,  
struct ilist *sink_list  UNUSED,  
int *  flow,  
struct ilist *  cut  
) 
Calculates minimum cut between source(s) and sink(s).
Flow is the array produced by NetA_flow() method when called with source_list and sink_list as the input. The output of this and NetA_flow() method should be the same.
graph  input graph  
source_list  list of sources  
sink_list  list of sinks (unused)  
flow  
[out]  cut  list of edges (cut) 
Definition at line 177 of file flow.c.
References _, dglGet_NodeCount(), G_calloc, G_fatal_error(), ilist::n_values, and ilist::value.
int NetA_split_vertices  (  dglGraph_s *  in, 
dglGraph_s *  out,  
int *  node_costs  
) 
Splits each vertex of in graph into two vertices.
The method splits each vertex of in graph into two vertices: in vertex and out vertex. Also, it adds an edge from an in vertex to the corresponding out vertex (capacity=2) and it adds an edge from out vertex to in vertex for each edge present in the in graph (forward capacity=1, backward capacity=0). If the id of a vertex is v then id of in vertex is 2*v1 and of out vertex 2*v.
in  from graph 
out  to graph 
node_costs  list of node costs 
Definition at line 269 of file flow.c.
References dglAddEdge(), dglInitialize(), dglNode_T_First(), dglNode_T_Initialize(), dglNode_T_Next(), dglNode_T_Release(), and dglNodeGet_Id().
dglInt32_t sign  (  dglInt32_t  x  ) 
Definition at line 25 of file flow.c.
References x.
Referenced by Rast3d_fpcompress_dissect_xdr_double().