Class ASCIIGraph
- All Implemented Interfaces:
it.unimi.dsi.lang.FlyweightPrototype<ImmutableGraph>
ImmutableGraph that corresponds to graphs stored in a human-readable
ASCII format where each line contains the list of successors of a given node.
The file format is as follows: the graph is stored in a file named basename.graph-txt.
The first line contains the number of nodes, n. Then, n lines follow, the i-th
line containing the successors of node i in increasing order
(nodes are numbered from 0 to n−1).
Successors are separated by a single space.
Contrarily to other classes, the load methods of this class do not always return instances of this class.
In particular, loadOffline(CharSequence) and loadOnce(InputStream) will return an instance of this class for
offline access. The instance will not provide random access, but sequential access will be backed by
the original text file and only one array of successor will be loaded in core memory at any time.
The load(CharSequence) method, on the other hand, will return an instance of
ArrayListMutableGraph built by copying an offline instance of this class.
Using ASCIIGraph to convert your data
A simple (albeit rather inefficient) way to import data into WebGraph is using ASCII graphs. Suppose you
create the following file, named example.graph-txt:
2 1 0 1Then, the command
java it.unimi.dsi.webgraph.BVGraph -g ASCIIGraph example bvexamplewill produce a compressed graph in
BVGraph format
with basename bvexample. Even more convenient is the loadOnce(InputStream)
method, which reads from an input stream an ASCII graph and exposes it for a single traversal. It
can be used, for instance, with the main method of BVGraph to
generate somehow an ASCII graph and store it in compressed form on the fly. The previous
example could be then rewritten as
java it.unimi.dsi.webgraph.BVGraph -1 -g ASCIIGraph dummy bvexample <example.graph-txt
-
Nested Class Summary
Nested classes/interfaces inherited from class it.unimi.dsi.webgraph.ImmutableGraph
ImmutableGraph.LoadMethod -
Field Summary
Fields inherited from class it.unimi.dsi.webgraph.ImmutableGraph
GRAPHCLASS_PROPERTY_KEY, NUMBER_OF_THREADS_PROPERTY, PROPERTIES_EXTENSION -
Constructor Summary
ConstructorsModifierConstructorDescriptionCreates a read-once ASCII graph.protectedASCIIGraph(CharSequence graphFile) -
Method Summary
Modifier and TypeMethodDescriptionstatic ImmutableGraphload(CharSequence basename) static ImmutableGraphload(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) static ASCIIGraphloadMapped(CharSequence basename) static ASCIIGraphloadMapped(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) static ASCIIGraphloadOffline(CharSequence basename) static ASCIIGraphloadOffline(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) static ASCIIGraphloadOnce(InputStream is) static ImmutableGraphloadSequential(CharSequence basename) Deprecated.static ASCIIGraphloadSequential(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) Deprecated.static voidnodeIterator(int from) Returns a node iterator for scanning the graph sequentially, starting from the given node.intnumNodes()Returns the number of nodes of this graph.splitNodeIterators(int howMany) Returns an array of node iterators, scanning each a portion of the nodes of a graph.static voidstore(ImmutableGraph graph, int shift, CharSequence basename) static voidstore(ImmutableGraph graph, CharSequence basename) static voidstore(ImmutableGraph graph, CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) Methods inherited from class it.unimi.dsi.webgraph.ImmutableSequentialGraph
copy, outdegree, randomAccess, successorArrayMethods inherited from class it.unimi.dsi.webgraph.ImmutableGraph
basename, equals, hasCopiableIterators, hashCode, load, nodeIterator, numArcs, outdegrees, store, store, successors, toString
-
Constructor Details
-
ASCIIGraph
- Throws:
NumberFormatExceptionIOException
-
ASCIIGraph
Creates a read-once ASCII graph. Instances created using this constructor can be only accessed using a single call tonodeIterator(int).- Parameters:
is- an input stream containing an ASCII graph.- Throws:
NumberFormatExceptionIOException
-
-
Method Details
-
numNodes
public int numNodes()Description copied from class:ImmutableGraphReturns the number of nodes of this graph.Albeit this method is not optional, it is allowed that this method throws an
UnsupportedOperationExceptionif this graph has never been entirely traversed using anode iterator. This apparently bizarre behaviour is necessary to support implementations asArcListASCIIGraph, which do not know the actual number of nodes until a traversal has been completed.- Specified by:
numNodesin classImmutableGraph- Returns:
- the number of nodes.
-
nodeIterator
Description copied from class:ImmutableGraphReturns a node iterator for scanning the graph sequentially, starting from the given node.- Overrides:
nodeIteratorin classImmutableSequentialGraph- Parameters:
from- the node from which the iterator will iterate.- Returns:
- a
NodeIteratorfor accessing nodes and successors sequentially.
-
splitNodeIterators
Description copied from class:ImmutableGraphReturns an array of node iterators, scanning each a portion of the nodes of a graph. Iterators are guaranteed to scan mutually disjoint sets of nodes, and every node is guaranteed to be scanned by one iterator.This is an optional operation. If implemented, though, the returned iterators must properly implement
NodeIterator.copy(int).- Overrides:
splitNodeIteratorsin classImmutableGraph- Parameters:
howMany- the number of iterators to be returned (at the end of the array, some of them may be empty).- Returns:
- the required iterators.
-
loadSequential
Deprecated.- Throws:
IOException
-
loadSequential
@Deprecated public static ASCIIGraph loadSequential(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) throws IOException Deprecated.- Throws:
IOException
-
loadOffline
- Throws:
IOException
-
loadOffline
public static ASCIIGraph loadOffline(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) throws IOException - Throws:
IOException
-
loadMapped
- Throws:
IOException
-
loadMapped
public static ASCIIGraph loadMapped(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) throws IOException - Throws:
IOException
-
loadOnce
- Throws:
IOException
-
load
- Throws:
IOException
-
load
public static ImmutableGraph load(CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) throws IOException - Throws:
IOException
-
store
public static void store(ImmutableGraph graph, CharSequence basename, it.unimi.dsi.logging.ProgressLogger unused) throws IOException - Throws:
IOException
-
store
- Throws:
IOException
-
store
- Throws:
IOException
-
main
public static void main(String[] args) throws IllegalArgumentException, SecurityException, IllegalAccessException, InvocationTargetException, NoSuchMethodException, IOException, com.martiansoftware.jsap.JSAPException, ClassNotFoundException, InstantiationException - Throws:
IllegalArgumentExceptionSecurityExceptionIllegalAccessExceptionInvocationTargetExceptionNoSuchMethodExceptionIOExceptioncom.martiansoftware.jsap.JSAPExceptionClassNotFoundExceptionInstantiationException
-