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  • Java JGraph subgraph

    - by Jeff Storey
    Is there a way to create a subgraph from a full graph in JGraph? When I update the subgraph, I want changes to propagate to the main graph. Does JGraph provide a relatively easy way for doing that out of the box (I couldn't seem to find one...)? thanks, Jeff

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  • Subgraph isomorphism on disconnected graphs with connection rules

    - by Mac
    Hello I was wondering if anyone knows about a solution to the following problem: Given a graph g as query and a set of graphs B with connection rules R. The connection rules describe how two graphs out of B can be linked together. Linking points are marked vertexes. Find all combination of graphs in B that contain g as a subgraph. Regards Mac

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  • Algorithms for subgraph isomorphism detection

    - by Jack
    This a NP Complete problem. More info can be found here http://en.wikipedia.org/wiki/Subgraph_isomorphism_problem The most widely used algorithm is the one proposed by Ullman. Can someone please explain the algorithm to me. I read a paper by him and couldn't understand much. Also what other algorithms for this problem. I am working on an image processing project.

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  • subgraph cluster ranking in dot

    - by Chris Becke
    I'm trying to use graphviz on media wiki as a documentation tool for software. First, I documented some class relationships which worked well. Everything was ranked vertically as expected. But, then, some of our modules are dlls, which I wanted to seperate into a box. When I added the nodes to a cluster, they got edged, but clusters seem to have a LR ranking rule. Or being added to a cluster broke the TB ranking of the nodes as the cluster now appears on the side of the graph. This graph represents what I am trying to do: at the moment, cluster1 and cluster2 appear to the right of cluster0. I want/need them to appear below. <graphviz> digraph d { subgraph cluster0 { A -> {B1 B2} B2 -> {C1 C2 C3} C1 -> D; } subgraph cluster1 { C2 -> dll1_A; dll1_A -> B1; } subgraph cluster2 { C3 -> dll2_A; } dll1_A -> dll2_A; } </graphviz>

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  • Find all complete sub-graphs within a graph

    - by mvid
    Is there a known algorithm or method to find all complete sub-graphs within a graph? I have an undirected, unweighted graph and I need to find all subgraphs within it where each node in the subgraph is connected to each other node in the subgraph. Is there an existing algorithm for this?

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  • Graph Algorithm To Find All Paths Between N Arbitrary Vertices

    - by russtbarnacle
    I have an graph with the following attributes: Undirected Not weighted Each vertex has a minimum of 2 and maximum of 6 edges connected to it. Vertex count will be < 100 I'm looking for paths between a random subset of the vertices (at least 2). The paths should simple paths that only go through any vertex once. My end goal is to have a set of routes so that you can start at one of the subset vertices and reach any of the other subset vertices. Its not necessary to pass through all the subset nodes when following a route. All of the algorithms I've found (Dijkstra,Depth first search etc.) seem to be dealing with paths between two vertices and shortest paths. Is there a known algorithm that will give me all the paths (I suppose these are subgraphs) that connect these subset of vertices?

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  • iPhone CoreData: How can I track/observe all changes within a subgraph?

    - by D Carney
    I have a NSManagedObjectContext in which I have a number of subclasses of NSManagedObjects such that some are containers for others. What I'd like to do is watch a top-level object to be notified of any changes to any of its properties, associations, or the properties/associations of any of the objects it contains. Using the context's 'hasChanges' doesn't give me enough granularity. The objects 'isUpdated' method only applies to the given object (and not anything in its associations). Is there a convenient (perhaps, KVO-based) was I can observe changes in a context that are limited to a subgraph?

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  • How can I find the shortest path between two subgraphs of a larger graph?

    - by Pops
    I'm working with a weighted, undirected multigraph (loops not permitted; most node connections have multiplicity 1; a few node connections have multiplicity 2). I need to find the shortest path between two subgraphs of this graph that do not overlap with each other. There are no other restrictions on which nodes should be used as start/end points. Edges can be selectively removed from the graph at certain times (as explained in my previous question) so it's possible that for two given subgraphs, there might not be any way to connect them. I'm pretty sure I've heard of an algorithm for this before, but I can't remember what it's called, and my Google searches for strings like "shortest path between subgraphs" haven't helped. Can someone suggest a more efficient way to do this than comparing shortest paths between all nodes in one subgraph with all nodes in the other subgraph? Or at least tell me the name of the algorithm so I can look it up myself? For example, if I have the graph below, the nodes circled in red might be one subgraph and the nodes circled in blue might be another. The edges would all have positive integer weights, although they're not shown in the image. I'd want to find whatever path has the shortest total cost as long as it starts at a red node and ends at a blue node. I believe this means the specific node positions and edge weights cannot be ignored. (This is just an example graph I grabbed off Wikimedia and drew on, not my actual problem.)

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  • Triangulating a partially triangulated mesh (2D)

    - by teodron
    Referring to the above exhibits, this is the scenario I am working with: starting with a planar graph (in my case, a 2D mesh) with a given triangulation, based on a certain criterion, the graph nodes are labeled as RED and BLACK. (A) a subgraph containing all the RED nodes (with edges between only the directly connected neighbours) is formed (note: although this figure shows a tree forming, it may well happen that the subgraph contain loops) (B) Problem: I need to quickly build a triangulation around the subgraph (e.g. as shown in figure C), but under the constraint that I have to keep the already present edges in the final result. Question: Is there a fast way of achieving this given a partially triangulated mesh? Ideally, the complexity should be in the O(n) class. Some side-remarks: it would be nice for the triangulation algorithm to take into account a certain vertex priority when adding edges (e.g. it should always try to build a "1-ring" structure around the most important nodes first - I can implement iteratively such a routine, but it's O(n^2) ). it would also be nice to reflect somehow the "hop distance" when adding edges: add edges first between the nodes that were "closer" to each other given the start topology. Nevertheless, disregarding the remarks, is there an already known scenario similar to this one where a triangulation is built upon a partially given set of triangles/edges?

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  • Automatic layout of manual network mapping

    - by Paul
    So I have a small business network mainly consisting of two routed layer-2 domains with a total of ca. 100 devices spread over ca. 2000m² production and office spaces. Typical problems to solve using the graph would be: Over what (cable) path is a PC connected to the server? Where to expect devices connected to a switch port? I want to generate a graph of the physical network topology: Nodes are endpoint devices, switch ports, wall outlets, patch panel ports etc. Edges are cable connections. Ideally, grouping edges (or segments) that pass through the same bundle could be grouped. Also I would like to augment the graph data with automatically gathered data (monitoring state, MAC address, Switch port <- MAC entries to build up parts of the map). At the moment I use graphviz for this inside a Confluence wiki like that: layout = "neato" overlap = scale subgraph { rankdir = "TB" subgraph cluster_r1pf1 { r1pf1 [label="{ Rack 1 PF 1 | { <p1>P1 | <p2>P2 | <p3>P3} }", shape=record] } subgraph cluster_switch1 { switch1 [label="{ Rack 1 Switch 1 | { <p1> P1 | <p1> P1 | <p3> P3} }", shape=record] } r1pf1:p1 -> switch1:p1 (obviously there are dozens of entries omitted here) Problem is: I have a hard time to influence graphviz to generate a bearable layout. Edges overlap so bad that you can't read the diagram anymore. The question is: What other tools (be it interactive like Visio, Omnigraffle or I/O-oriented like graphviz) exist that would allow an easily versionable (as in: Operates on a text file) documentation that is both machine and human readable and editable? Why not OmniGraffle or Visio? Well we don't have Macs and Visio is not available at the moment. To buy it I would need good arguments. Automation would be one of that. But last time I looked, versioning Visio files or even thinking about automatic handling was a nightmare. Related: Network Mapping Tools basically asks the same with a focus on generating the complete graph automatically (but without the need to document cabling connections) Recommendations for automatic computer inventory brings up links of "all-in-one" solutions

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  • Graphiz: how to set 'default' arrow style?

    - by sdaau
    Hi all, Consider this dot language code: digraph graphname { subgraph clusterA { node [shape=plaintext,style=filled]; 1 -> 2 [arrowhead=normal,arrowtail=dot]; 2 -> 3 -> X2 -> 5; 6; 7; label = "A"; color=blue } } In the above example, only the 1 -> 2 connection will have the arrowhead=normal,arrowtail=dot style applied; all the other arrows will be of the "default" style. My question is - how do I set the arrow style (for the entire subgraph - or for the entire graph), without having to copy paste "[arrowhead=normal,arrowtail=dot];" next to each edge connection? Thanks in advance, Cheers!

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  • help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code (PART II)

    - by Pitelk
    Hi all , i cannot understand a certain part of the paper published by Donald Johnson about finding cycles (Circuits) in a graph. More specific i cannot understand what is the matrix Ak which is mentioned in the following line of the pseudo code : Ak:=adjacency structure of strong component K with least vertex in subgraph of G induced by {s,s+1,....n}; to make things worse some lines after is mentins " for i in Vk do " without declaring what the Vk is... As far i have understand we have the following: 1) in general, a strong component is a sub-graph of a graph, in which for every node of this sub-graph there is a path to any node of the sub-graph (in other words you can access any node of the sub-graph from any other node of the sub-graph) 2) a sub-graph induced by a list of nodes is a graph containing all these nodes plus all the edges connecting these nodes. in paper the mathematical definition is " F is a subgraph of G induced by W if W is subset of V and F = (W,{u,y)|u,y in W and (u,y) in E)}) where u,y are edges , E is the set of all the edges in the graph, W is a set of nodes. 3)in the code implementation the nodes are named by integer numbers 1 ... n. 4) I suspect that the Vk is the set of nodes of the strong component K. now to the question. Lets say we have a graph G= (V,E) with V = {1,2,3,4,5,6,7,8,9} which it can be divided into 3 strong components the SC1 = {1,4,7,8} SC2= {2,3,9} SC3 = {5,6} (and their edges) Can anybody give me an example for s =1, s= 2, s= 5 what if going to be the Vk and Ak according to the code? The pseudo code is in my previous question in http://stackoverflow.com/questions/2908575/help-in-the-donalds-b-johnsons-algorithm-i-cannot-understand-the-pseudo-code and the paper can be found at http://stackoverflow.com/questions/2908575/help-in-the-donalds-b-johnsons-algorithm-i-cannot-understand-the-pseudo-code thank you in advance

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  • Why is graphviz drawing two arrows, and using a weird order?

    - by dmd
    Why is graphviz drawing two arrows from uncap_spike to peel, and why is it drawing peel to the right of hang? I want uncap_spike - peel - hang - spike, in that order, with one edge between each. digraph hangers { compound=true fontname="Gill Sans" node [fontname="Gill Sans" shape=box fillcolor=white style="rounded, filled"] edge [fontname="Gill Sans"] subgraph cluster_prep { style="filled" label=Prep gather [shape=Mrecord label="{gather | EtOH swab\nvented tubing}"] uncap_bottle [label="uncap bottle"] uncap_spike [label="uncap spike"] swab [shape=Mrecord label="{swab EtOH | wait 30 seconds for sterility}"] gather -> uncap_bottle -> swab -> uncap_spike {rank=same gather uncap_bottle swab uncap_spike} } subgraph cluster_hang { style=filled label=Hang {rank=same peel hang} } {rank=same uncap_spike -> peel -> hang -> spike -> prime} hang -> rip [color=firebrick] rip [label="eyelet\nripped" style="filled" shape=octagon regular fontcolor=white fontsize=10 width=.5 fixedsize color=firebrick fillcolor=firebrick ] swab -> not_sterile [color=firebrick] not_sterile [label="not\nsterile" style="filled" shape=octagon regular fontcolor=white fontsize=10 width=.5 fixedsize color=firebrick fillcolor=firebrick ] }

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  • Finding minimum cut-sets between bounded subgraphs

    - by Tore
    If a game map is partitioned into subgraphs, how to minimize edges between subgraphs? I have a problem, Im trying to make A* searches through a grid based game like pacman or sokoban, but i need to find "enclosures". What do i mean by enclosures? subgraphs with as few cut edges as possible given a maximum size and minimum size for number of vertices for each subgraph that act as a soft constraints. Alternatively you could say i am looking to find bridges between subgraphs, but its generally the same problem. Given a game that looks like this, what i want to do is find enclosures so that i can properly find entrances to them and thus get a good heuristic for reaching vertices inside these enclosures. So what i want is to find these colored regions on any given map. My Motivation The reason for me bothering to do this and not just staying content with the performance of a simple manhattan distance heuristic is that an enclosure heuristic can give more optimal results and i would not have to actually do the A* to get some proper distance calculations and also for later adding competitive blocking of opponents within these enclosures when playing sokoban type games. Also the enclosure heuristic can be used for a minimax approach to finding goal vertices more properly. A possible solution to the problem is the Kernighan-Lin algorithm: function Kernighan-Lin(G(V,E)): determine a balanced initial partition of the nodes into sets A and B do A1 := A; B1 := B compute D values for all a in A1 and b in B1 for (i := 1 to |V|/2) find a[i] from A1 and b[i] from B1, such that g[i] = D[a[i]] + D[b[i]] - 2*c[a][b] is maximal move a[i] to B1 and b[i] to A1 remove a[i] and b[i] from further consideration in this pass update D values for the elements of A1 = A1 / a[i] and B1 = B1 / b[i] end for find k which maximizes g_max, the sum of g[1],...,g[k] if (g_max > 0) then Exchange a[1],a[2],...,a[k] with b[1],b[2],...,b[k] until (g_max <= 0) return G(V,E) My problem with this algorithm is its runtime at O(n^2 * lg(n)), i am thinking of limiting the nodes in A1 and B1 to the border of each subgraph to reduce the amount of work done. I also dont understand the c[a][b] cost in the algorithm, if a and b do not have an edge between them is the cost assumed to be 0 or infinity, or should i create an edge based on some heuristic. Do you know what c[a][b] is supposed to be when there is no edge between a and b? Do you think my problem is suitable to use a multi level problem? Why or why not? Do you have a good idea for how to reduce the work done with the kernighan-lin algorithm for my problem?

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  • Java graph library for comparing 2 graphs

    - by user311909
    Hello, Does anyone know a good java library for graph comparing by searching maximal common subgraph isomorphism to get information about their similarity? I do not want to compare graphs based on node labels. Or is there any other way how to topologicaly compare graphs with good java library? Now I am using library SimPack and it is usefull but I need something more. Any suggestions will be very helpful. Thanks in advance

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  • Better Flex memory profiling tools

    - by verveguy
    Does anyone know of any better tools that the Flex Builder Profiler? I've googled and googled to no avail. While the FB tools are OK for small apps / small leak situations, they're nowhere near adequate for wading through the thicket of object references that can arise in a large scale Flex app (that is leaking memory heavily). In particular, any reasonably complex view structure ends up with huge numbers of parent/child object references to the top level view - none of which are at all relevant to finding the one or two refs from outside the parent child subgraph that are causing the whole bolus to be non-GC'able. If no one has any better suggestions, I'm seriously considering writing a tool to parse the saved profile dumps that Flex Builder can generate so that I can do my own "graph pruning" to find the important refs. If I go this route, collaboration would be welcome!

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  • [C++] Write connected components of a graph using Boost Graph

    - by conradlee
    I have an file that is a long list of weighted edges, in the following form node1_id node2_id weight node1_id node3_id weight and so on. So one weighted edge per line. I want to load this file into boost graph and find the connected components in the graph. Each of these connected components is a subgraph. For each of these component subgraphs, I want to write the edges in the above-described format. I want to do all this using boost graph. This problem is in principle simple, it's just I'm not sure how to implement it neatly because I don't know my way around Boost Graph. I have already spent some hours and have code that will find the connected components, but my version is surely much longer and more complicated that necessary---I'm hoping there's a boost-graph ninja out there that can show me the right, easy way.

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  • Why does tokyo tyrant slow down exponentially even after adjusting bnum?

    - by HenryL
    Has anyone successfully used Tokyo Cabinet / Tokyo Tyrant with large datasets? I am trying to upload a subgraph of the Wikipedia datasource. After hitting about 30 million records, I get exponential slow down. This occurs with both the HDB and BDB databases. I adjusted bnum to 2-4x the expected number of records for the HDB case with only a slight speed up. I also set xmsiz to 1GB or so but ultimately I still hit a wall. It seems that Tokyo Tyrant is basically an in memory database and after you exceed the xmsiz or your RAM, you get a barely usable database. Has anyone else encountered this problem before? Were you able to solve it?

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  • Managing the layout of a Java MainFrame of Canvas3d

    - by John N
    Hi, Im trying to organise the layout of four canvas3d objects in a single MainFrame. Iv tried using some layout managers but none are working (or im doing it wrong). Can anyone give me advice or point me to a way to get this to display the four canvas's as a grid of four? Thanks, John public class Main { public static void Main(){ Window win = new Window(); } } import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.Locale; import javax.media.j3d.PhysicalBody; import javax.media.j3d.PhysicalEnvironment; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.View; import javax.media.j3d.ViewPlatform; import javax.media.j3d.VirtualUniverse; import javax.vecmath.Vector3f; import com.sun.j3d.utils.picking.PickCanvas; public class Universe { boolean camera = true; Canvas3D canvas1, canvas2, canvas3, canvas4; VirtualUniverse universe; Locale locale; TransformGroup vpTrans1, vpTransRight, vpTransFront, vpTransPers; TransformGroup mouseTransform = null; View view1, view2, view3, view4; BranchGroup scene; PickCanvas pickCanvas1 = null; PickCanvas pickCanvas2 = null; PickCanvas pickCanvas3 = null; PickCanvas pickCanvas4 = null; BranchGroup obj = new BranchGroup(); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); //Temp vars for cam movement public Universe(Canvas3D c1, Canvas3D c2, Canvas3D c3, Canvas3D c4, BranchGroup scene) { this.canvas1 = c1; this.canvas2 = c2; this.canvas3 = c3; this.canvas4 = c4; this.scene = scene; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view1 = new View(); view1.addCanvas3D(c1); view1.addCanvas3D(c2); view1.addCanvas3D(c3); view1.addCanvas3D(c4); view1.setPhysicalBody(body); view1.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 2.0f)); ViewPlatform vp = new ViewPlatform(); vpTrans1 = new TransformGroup(t); vpTrans1.addChild(vp); vpRoot.addChild(vpTrans1); vpRoot.addChild(scene); view1.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } } import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.Locale; import javax.media.j3d.PhysicalBody; import javax.media.j3d.PhysicalEnvironment; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.View; import javax.media.j3d.ViewPlatform; import javax.media.j3d.VirtualUniverse; import javax.vecmath.Vector3f; import com.sun.j3d.utils.picking.PickCanvas; public class Universe { boolean camera = true; Canvas3D canvas1, canvas2, canvas3, canvas4; VirtualUniverse universe; Locale locale; TransformGroup vpTrans1, vpTransRight, vpTransFront, vpTransPers; TransformGroup mouseTransform = null; View view1, view2, view3, view4; BranchGroup scene; PickCanvas pickCanvas1 = null; PickCanvas pickCanvas2 = null; PickCanvas pickCanvas3 = null; PickCanvas pickCanvas4 = null; BranchGroup obj = new BranchGroup(); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); //Temp vars for cam movement public Universe(Canvas3D c1, Canvas3D c2, Canvas3D c3, Canvas3D c4, BranchGroup scene) { this.canvas1 = c1; this.canvas2 = c2; this.canvas3 = c3; this.canvas4 = c4; this.scene = scene; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view1 = new View(); view1.addCanvas3D(c1); view1.addCanvas3D(c2); view1.addCanvas3D(c3); view1.addCanvas3D(c4); view1.setPhysicalBody(body); view1.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 2.0f)); ViewPlatform vp = new ViewPlatform(); vpTrans1 = new TransformGroup(t); vpTrans1.addChild(vp); vpRoot.addChild(vpTrans1); vpRoot.addChild(scene); view1.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } }

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  • Rotation of viewplatform in Java3D

    - by user29163
    I have just started with Java3D programming. I thought I had built up some basic intuition about how the scene graph works, but something that should work, does not work. I made a simple program for rotating a pyramid around the y-axis. This was done just by adding a RotationInterpolator R to the TransformGroup above the pyramid. Then I thought hey, can I now remove the RotationInterpolator from this TransformGroup, then add it to the TransformGroup above my ViewPlatform leaf. This should work if I have understood how things work. Adding the RotationInterpolator to this TransformGroup, should make the children of this TransformGroup rotate, and the ViewingPlatform is a child of the TransformGroup. Any ideas on where my reasoning is flawed? Here is the code for setting up the universe, and the view branchgroup. import java.awt.*; import java.awt.event.*; import javax.media.j3d.*; import javax.vecmath.*; public class UniverseBuilder { // User-specified canvas Canvas3D canvas; // Scene graph elements to which the user may want access VirtualUniverse universe; Locale locale; TransformGroup vpTrans; View view; public UniverseBuilder(Canvas3D c) { this.canvas = c; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view = new View(); view.addCanvas3D(c); view.setPhysicalBody(body); view.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); Transform3D s = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 10.0f)); t.rotX(-Math.PI/4); s.set(new Vector3f(0.0f, 0.0f, 10.0f)); //forandre verdier her for å endre viewing position t.mul(s); ViewPlatform vp = new ViewPlatform(); vpTrans = new TransformGroup(t); vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); // Rotator stuff Transform3D yAxis = new Transform3D(); //yAxis.rotY(Math.PI/2); Alpha rotationAlpha = new Alpha( -1, Alpha.INCREASING_ENABLE, 0, 0,4000, 0, 0, 0, 0, 0); RotationInterpolator rotator = new RotationInterpolator( rotationAlpha, vpTrans, yAxis, 0.0f, (float) Math.PI*2.0f); RotationInterpolator rotator2 = new RotationInterpolator( rotationAlpha, vpTrans); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 1000.0); rotator.setSchedulingBounds(bounds); vpTrans.addChild(rotator); vpTrans.addChild(vp); vpRoot.addChild(vpTrans); view.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } public void addBranchGraph(BranchGroup bg) { locale.addBranchGraph(bg); } }

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  • Trouble rotating viewplatform in Java3D [closed]

    - by user29163
    I have just started with Java3D programming. I thought I had built up some basic intuition about how the scene graph works, but something that should work, does not work. I made a simple program for rotating a pyramid around the y-axis. This was done just by adding a RotationInterpolator R to the TransformGroup above the pyramid. Then I thought hey, can I now remove the RotationInterpolator from this TransformGroup, then add it to the TransformGroup above my ViewPlatform leaf. This should work if I have understood how things work. Adding the RotationInterpolator to this TransformGroup, should make the children of this TransformGroup rotate, and the ViewingPlatform is a child of the TransformGroup. Any ideas on where my reasoning is flawed? Here is the code for setting up the universe, and the view branchgroup. import java.awt.*; import java.awt.event.*; import javax.media.j3d.*; import javax.vecmath.*; public class UniverseBuilder { // User-specified canvas Canvas3D canvas; // Scene graph elements to which the user may want access VirtualUniverse universe; Locale locale; TransformGroup vpTrans; View view; public UniverseBuilder(Canvas3D c) { this.canvas = c; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view = new View(); view.addCanvas3D(c); view.setPhysicalBody(body); view.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); Transform3D s = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 10.0f)); t.rotX(-Math.PI/4); s.set(new Vector3f(0.0f, 0.0f, 10.0f)); //forandre verdier her for å endre viewing position t.mul(s); ViewPlatform vp = new ViewPlatform(); vpTrans = new TransformGroup(t); vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); // Rotator stuff Transform3D yAxis = new Transform3D(); //yAxis.rotY(Math.PI/2); Alpha rotationAlpha = new Alpha( -1, Alpha.INCREASING_ENABLE, 0, 0,4000, 0, 0, 0, 0, 0); RotationInterpolator rotator = new RotationInterpolator( rotationAlpha, vpTrans, yAxis, 0.0f, (float) Math.PI*2.0f); RotationInterpolator rotator2 = new RotationInterpolator( rotationAlpha, vpTrans); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 1000.0); rotator.setSchedulingBounds(bounds); vpTrans.addChild(rotator); vpTrans.addChild(vp); vpRoot.addChild(vpTrans); view.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } public void addBranchGraph(BranchGroup bg) { locale.addBranchGraph(bg); } }

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  • help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code

    - by Pitelk
    Hi , does anyone know the Donald B. Johnson's algorithm which enumarates all the elementary circuits (cycles) in a Directed graph? link text I have the paper he had published in 1975 but I cannot understand the pseudo-code. My goal is to implement this algorithm in java. Some questions i have is for example what is the matrix Ak it refers to. In the pseudo code mentions that Ak:=adjacency structure of strong component K with least vertex in subgraph of G induced by {s,s+1,....n}; Does that mean i have to implement another algorithm that finds the Ak matrix? Another question is what the following means? begin logical f; Does also the line "logical procedure CIRCUIT (integer value v);" means that the circuit procedure returns a logical variable. In the pseudo code also has the line "CIRCUIT := f;" . Does this mean? It would be great if someone could translate this 1970's pseudocode to a more modern type of pseudo code so i can understand it in case you are interested to help but you cannot find the paper please email me at [email protected] and i will send you the paper. Thanks in advance

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  • finding ALL cycles in a huge sparse matrix

    - by Andy
    Hi there, First of all I'm quite a Java beginner, so I'm not sure if this is even possible! Basically I have a huge (3+million) data source of relational data (i.e. A is friends with B+C+D, B is friends with D+G+Z (but not A - i.e. unmutual) etc.) and I want to find every cycle within this (not necessarily connected) directed graph. I've found this thread (http://stackoverflow.com/questions/546655/finding-all-cycles-in-graph/549402#549402) which has pointed me to Donald Johnson's (elementary) cycle-finding algorithm which, superficially at least, looks like it'll do what I'm after (I'm going to try when I'm back at work on Tuesday - thought it wouldn't hurt to ask in the meanwhile!). I had a quick scan through the code of the Java implementation of Johnson's algorithm (in that thread) and it looks like a matrix of relations is the first step, so I guess my questions are: a) Is Java capable of handling a 3+million*3+million matrix? (was planning on representing A-friends-with-B by a binary sparse matrix) b) Do I need to find every connected subgraph as my first problem, or will cycle-finding algorithms handle disjoint data? c) Is this actually an appropriate solution for the problem? My understanding of "elementary" cycles is that in the graph below, rather than picking out A-B-C-D-E-F it'll pick out A-B-F, B-C-D etc. but that's not the end of the world given the task. E / \ D---F / \ / \ C---B---A d) If necessary, I can simplify the problem by enforcing mutuality in relations - i.e. A-friends-with-B <== B-friends-with-A, and if really necessary I can maybe cut down the data size, but realistically it is always going to be around the 1mil mark. z) Is this a P or NP task?! Am I biting off more than I can chew? Thanks all, any help appreciated! Andy

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  • Algorithmia Source Code released on CodePlex

    - by FransBouma
    Following the release of our BCL Extensions Library on CodePlex, we have now released the source-code of Algorithmia on CodePlex! Algorithmia is an algorithm and data-structures library for .NET 3.5 or higher and is one of the pillars LLBLGen Pro v3's designer is built on. The library contains many data-structures and algorithms, and the source-code is well documented and commented, often with links to official descriptions and papers of the algorithms and data-structures implemented. The source-code is shared using Mercurial on CodePlex and is licensed under the friendly BSD2 license. User documentation is not available at the moment but will be added soon. One of the main design goals of Algorithmia was to create a library which contains implementations of well-known algorithms which weren't already implemented in .NET itself. This way, more developers out there can enjoy the results of many years of what the field of Computer Science research has delivered. Some algorithms and datastructures are known in .NET but are re-implemented because the implementation in .NET isn't efficient for many situations or lacks features. An example is the linked list in .NET: it doesn't have an O(1) concat operation, as every node refers to the containing LinkedList object it's stored in. This is bad for algorithms which rely on O(1) concat operations, like the Fibonacci heap implementation in Algorithmia. Algorithmia therefore contains a linked list with an O(1) concat feature. The following functionality is available in Algorithmia: Command, Command management. This system is usable to build a fully undo/redo aware system by building your object graph using command-aware classes. The Command pattern is implemented using a system which allows transparent undo-redo and command grouping so you can use it to make a class undo/redo aware and set properties, use its contents without using commands at all. The Commands namespace is the namespace to start. Classes you'd want to look at are CommandifiedMember, CommandifiedList and KeyedCommandifiedList. See the CommandQueueTests in the test project for examples. Graphs, Graph algorithms. Algorithmia contains a sophisticated graph class hierarchy and algorithms implemented onto them: non-directed and directed graphs, as well as a subgraph view class, which can be used to create a view onto an existing graph class which can be self-maintaining. Algorithms include transitive closure, topological sorting and others. A feature rich depth-first search (DFS) crawler is available so DFS based algorithms can be implemented quickly. All graph classes are undo/redo aware, as they can be set to be 'commandified'. When a graph is 'commandified' it will do its housekeeping through commands, which makes it fully undo-redo aware, so you can remove, add and manipulate the graph and undo/redo the activity automatically without any extra code. If you define the properties of the class you set as the vertex type using CommandifiedMember, you can manipulate the properties of vertices and the graph contents with full undo/redo functionality without any extra code. Heaps. Heaps are data-structures which have the largest or smallest item stored in them always as the 'root'. Extracting the root from the heap makes the heap determine the next in line to be the 'maximum' or 'minimum' (max-heap vs. min-heap, all heaps in Algorithmia can do both). Algorithmia contains various heaps, among them an implementation of the Fibonacci heap, one of the most efficient heap datastructures known today, especially when you want to merge different instances into one. Priority queues. Priority queues are specializations of heaps. Algorithmia contains a couple of them. Sorting. What's an algorithm library without sort algorithms? Algorithmia implements a couple of sort algorithms which sort the data in-place. This aspect is important in situations where you want to sort the elements in a buffer/list/ICollection in-place, so all data stays in the data-structure it already is stored in. PropertyBag. It re-implements Tony Allowatt's original idea in .NET 3.5 specific syntax, which is to have a generic property bag and to be able to build an object in code at runtime which can be bound to a property grid for editing. This is handy for when you have data / settings stored in XML or other format, and want to create an editable form of it without creating many editors. IEditableObject/IDataErrorInfo implementations. It contains default implementations for IEditableObject and IDataErrorInfo (EditableObjectDataContainer for IEditableObject and ErrorContainer for IDataErrorInfo), which make it very easy to implement these interfaces (just a few lines of code) without having to worry about bookkeeping during databinding. They work seamlessly with CommandifiedMember as well, so your undo/redo aware code can use them out of the box. EventThrottler. It contains an event throttler, which can be used to filter out duplicate events in an event stream coming into an observer from an event. This can greatly enhance performance in your UI without needing to do anything other than hooking it up so it's placed between the event source and your real handler. If your UI is flooded with events from data-structures observed by your UI or a middle tier, you can use this class to filter out duplicates to avoid redundant updates to UI elements or to avoid having observers choke on many redundant events. Small, handy stuff. A MultiValueDictionary, which can store multiple unique values per key, instead of one with the default Dictionary, and is also merge-aware so you can merge two into one. A Pair class, to quickly group two elements together. Multiple interfaces for helping with building a de-coupled, observer based system, and some utility extension methods for the defined data-structures. We regularly update the library with new code. If you have ideas for new algorithms or want to share your contribution, feel free to discuss it on the project's Discussions page or send us a pull request. Enjoy!

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