
Java example source code file (GraphLoader.java)
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The GraphLoader.java Java example source code
package org.deeplearning4j.graph.data;
import org.deeplearning4j.graph.api.Edge;
import org.deeplearning4j.graph.api.Vertex;
import org.deeplearning4j.graph.data.impl.DelimitedEdgeLineProcessor;
import org.deeplearning4j.graph.data.impl.WeightedEdgeLineProcessor;
import org.deeplearning4j.graph.graph.Graph;
import org.deeplearning4j.graph.vertexfactory.StringVertexFactory;
import org.deeplearning4j.graph.vertexfactory.VertexFactory;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.List;
/** Utility methods for loading graphs
*
*/
public class GraphLoader {
/** Simple method for loading an undirected graph, where the graph is represented by a edge list with one edge
* per line with a delimiter in between<br>
* This method assumes that all lines in the file are of the form {@code i<delim>j} where i and j are integers
* in range 0 to numVertices inclusive, and "<delim>" is the userprovided delimiter
* <b>Note: this method calls {@link #loadUndirectedGraphEdgeListFile(String, int, String, boolean)} with allowMultipleEdges = true.
* @param path Path to the edge list file
* @param numVertices number of vertices in the graph
* @return graph
* @throws IOException if file cannot be read
*/
public static Graph<String,String> loadUndirectedGraphEdgeListFile(String path, int numVertices, String delim) throws IOException {
return loadUndirectedGraphEdgeListFile(path,numVertices,delim,true);
}
/** Simple method for loading an undirected graph, where the graph is represented by a edge list with one edge
* per line with a delimiter in between<br>
* This method assumes that all lines in the file are of the form {@code i<delim>j} where i and j are integers
* in range 0 to numVertices inclusive, and "<delim>" is the userprovided delimiter
* @param path Path to the edge list file
* @param numVertices number of vertices in the graph
* @param allowMultipleEdges If set to false, the graph will not allow multiple edges between any two vertices to exist. However,
* checking for duplicates during graph loading can be costly, so use allowMultipleEdges=true when
* possible.
* @return graph
* @throws IOException if file cannot be read
*/
public static Graph<String,String> loadUndirectedGraphEdgeListFile(String path, int numVertices, String delim, boolean allowMultipleEdges) throws IOException {
Graph<String,String> graph = new Graph<>(numVertices,allowMultipleEdges,new StringVertexFactory());
EdgeLineProcessor<String> lineProcessor = new DelimitedEdgeLineProcessor(delim,false);
try(BufferedReader br = new BufferedReader(new FileReader(new File(path)))){
String line;
while( (line = br.readLine()) != null ) {
Edge<String> edge = lineProcessor.processLine(line);
if(edge != null){
graph.addEdge(edge);
}
}
}
return graph;
}
/**Method for loading a weighted graph from an edge list file, where each edge (inc. weight) is represented by a
* single line. Graph may be directed or undirected<br>
* This method assumes that edges are of the format: {@code fromIndex<delim>toIndexedgeWeight} where {@code }
* is the delimiter.
* <b>Note: this method calls {@link #loadWeightedEdgeListFile(String, int, String, boolean, boolean, String...)} with allowMultipleEdges = true.
* @param path Path to the edge list file
* @param numVertices The number of vertices in the graph
* @param delim The delimiter used in the file (typically: "," or " " etc)
* @param directed whether the edges should be treated as directed (true) or undirected (false)
* @param ignoreLinesStartingWith Starting characters for comment lines. May be null. For example: "//" or "#"
* @return The graph
* @throws IOException
*/
public static Graph<String,Double> loadWeightedEdgeListFile(String path, int numVertices, String delim, boolean directed,
String... ignoreLinesStartingWith) throws IOException {
return loadWeightedEdgeListFile(path,numVertices,delim,directed,true,ignoreLinesStartingWith);
}
/**Method for loading a weighted graph from an edge list file, where each edge (inc. weight) is represented by a
* single line. Graph may be directed or undirected<br>
* This method assumes that edges are of the format: {@code fromIndex<delim>toIndexedgeWeight} where {@code }
* is the delimiter.
* @param path Path to the edge list file
* @param numVertices The number of vertices in the graph
* @param delim The delimiter used in the file (typically: "," or " " etc)
* @param directed whether the edges should be treated as directed (true) or undirected (false)
* @param allowMultipleEdges If set to false, the graph will not allow multiple edges between any two vertices to exist. However,
* checking for duplicates during graph loading can be costly, so use allowMultipleEdges=true when
* possible.
* @param ignoreLinesStartingWith Starting characters for comment lines. May be null. For example: "//" or "#"
* @return The graph
* @throws IOException
*/
public static Graph<String,Double> loadWeightedEdgeListFile(String path, int numVertices, String delim, boolean directed,
boolean allowMultipleEdges, String... ignoreLinesStartingWith) throws IOException {
Graph<String,Double> graph = new Graph<>(numVertices,allowMultipleEdges,new StringVertexFactory());
EdgeLineProcessor<Double> lineProcessor = new WeightedEdgeLineProcessor(delim,directed,ignoreLinesStartingWith);
try(BufferedReader br = new BufferedReader(new FileReader(new File(path)))){
String line;
while( (line = br.readLine()) != null ) {
Edge<Double> edge = lineProcessor.processLine(line);
if(edge != null){
graph.addEdge(edge);
}
}
}
return graph;
}
/** Load a graph into memory, using a given EdgeLineProcessor.
* Assume one edge per line
* @param path Path to the file containing the edges, one per line
* @param lineProcessor EdgeLineProcessor used to convert lines of text into a graph (or null for comment lines etc)
* @param vertexFactory Used to create vertices
* @param numVertices number of vertices in the graph
* @param allowMultipleEdges whether the graph should allow multiple edges between a given pair of vertices or not
* @return IGraph
*/
public static <V,E> Graph loadGraph(String path, EdgeLineProcessor lineProcessor,
VertexFactory<V> vertexFactory, int numVertices,
boolean allowMultipleEdges) throws IOException {
Graph<V,E> graph = new Graph<>(numVertices,allowMultipleEdges,vertexFactory);
try(BufferedReader br = new BufferedReader(new FileReader(new File(path)))){
String line;
while( (line = br.readLine()) != null ) {
Edge<E> edge = lineProcessor.processLine(line);
if(edge != null){
graph.addEdge(edge);
}
}
}
return graph;
}
/** Load graph, assuming vertices are in one file and edges are in another file.
*
* @param vertexFilePath Path to file containing vertices, one per line
* @param edgeFilePath Path to the file containing edges, one per line
* @param vertexLoader VertexLoader, for loading vertices from the file
* @param edgeLineProcessor EdgeLineProcessor, converts text lines into edges
* @param allowMultipleEdges whether the graph should allow (or filter out) multiple edges
* @return IGraph loaded from files
*/
public static <V,E> Graph loadGraph(String vertexFilePath, String edgeFilePath, VertexLoader vertexLoader,
EdgeLineProcessor<E> edgeLineProcessor, boolean allowMultipleEdges ) throws IOException {
//Assume vertices are in one file
//And edges are in another file
List<Vertex vertices = vertexLoader.loadVertices(vertexFilePath);
Graph<V,E> graph = new Graph<>(vertices,allowMultipleEdges);
try(BufferedReader br = new BufferedReader(new FileReader(new File(edgeFilePath)))){
String line;
while( (line = br.readLine()) != null ) {
Edge<E> edge = edgeLineProcessor.processLine(line);
if(edge != null){
graph.addEdge(edge);
}
}
}
return graph;
}
}
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