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  • How to find whole graph coverage path in dynamic state-flow diagram?

    - by joseph
    Hello, As I've been researching algorithms for path finding in graph, I found interesting problem. Definition of situation: 1)State diagram can have p states, and s Boolean Fields, and z Int Fields 2)Every state can have q ingoing and r outgoing transitions, and h Int fields (h belongs to z - see above) 3)Every transition can have only 1 event, and only 1 action 4)every action can change n Boolean Fields, and x Int Fields 5)every event can have one trigger from combination of any count of Boolean Fields in diagram 6)Transition can be in OPEN/CLOSED form. If the transition is open/closed depends on trigger2 compounded from 0..c Boolean fields. 7) I KNOW algorithm for finding shortest paths from state A to state B. 8) I KNOW algorithm for finding path that covers all states and transitions of whole state diagram, if all transitions are OPEN. Now, what is the goal: I need to find shortest path that covers all states and transitions in dynamically changing state diagram described above. When an action changes some int field, the algorithm should go through all states that have changed int field. The algorithm should also be able to open and close transition (by going through transitions that open and close another transitions by action) in the way that the founded path will be shortest and covers all transitions and states. Any idea how to solve it? I will be really pleased for ANY idea. Thanks for answers.

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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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  • Scene Graph for Deferred Rendering Engine

    - by Roy T.
    As a learning exercise I've written a deferred rendering engine. Now I'd like to add a scene graph to this engine but I'm a bit puzzled how to do this. On a normal (forward rendering engine) I would just add all items (All implementing IDrawable and IUpdateAble) to my scene graph, than travel the scene-graph breadth first and call Draw() everywhere. However in a deferred rendering engine I have to separate draw calls. First I have to draw the geometry, then the shadow casters and then the lights (all to different render targets), before I combine them all. So in this case I can't just travel over the scene graph and just call draw. The way I see it I either have to travel over the entire scene graph 3 times, checking what kind of object it is that has to be drawn, or I have to create 3 separate scene graphs that are somehow connected to each other. Both of these seem poor solutions, I'd like to handle scene objects more transparent. One other solution I've thought of was traveling trough the scene graph as normal and adding items to 3 separate lists, separating geometry, shadow casters and lights, and then iterating these lists to draw the correct stuff, is this better, and is it wise to repopulate 3 lists every frame?

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  • Display Graph using Boost Graph Library

    - by TheTSPSolver
    Can anyone please tell me that once I've created a graph using Boost Graph library, how can I display that graph? My biggest concern is that the edge weights are coming from an exernal data source over the network. And I need to be able to display the edgeweights live as they get updated.

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  • Eliminating cyclic flows from a graph

    - by Jon Harrop
    I have a directed graph with flow volumes along edges and I would like to simplify it by removing all cyclic flows. This can be done by finding the minimum of the flow volumes along each edge in any given cycle and reducing the flows of every edge in the cycle by that minimum volume, deleting edges with zero flow. When all cyclic flows have been removed the graph will be acyclic. For example, if I have a graph with vertices A, B and C with flows of 1 from A?B, 2 from B?C and 3 from C?A then I can rewrite this with no flow from A?B, 1 from B?C and 2 from C?A. The number of edges in the graph has reduced from 3 to 2 and the resulting graph is acyclic. Which algorithm(s), if any, solve this problem?

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  • Architecture for Social Graph data that has a Time Frame Associated?

    - by Jay Stevens
    I am adding some "social" type features to an existing application. There are a limited # of node & edge types. Overall the data itself is relatively small (50,000 - 70,000 for each type of node) there will be a number of edges (relationships) between them (almost all directional). This, I know, is relatively easy to represent with an SDF store (such as BrightstarDB) or something like Microsoft's Trinity (or really many of the noSQL options). The thing that, I think, makes this a unique use case is that each relationship will have a timeframe associated with it (start and end dates). Right now, I'm thinking of just storing this in a relational structure and dealing with the headaches of "traversing the graph", but I'm looking for suggestions on a better approach (both in terms of data structure and server): Column ================ From_Node_ID Relationship To_Node_ID StartDate EndDate Any suggestions or thoughts are welcomed.

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  • Detecting Asymptotes in a Graph

    - by nasufara
    I am creating a graphing calculator in Java as a project for my programming class. There are two main components to this calculator: the graph itself, which draws the line(s), and the equation evaluator, which takes in an equation as a String and... well, evaluates it. To create the line, I create a Path2D.Double instance, and loop through the points on the line. To do this, I calculate as many points as the graph is wide (e.g. if the graph itself is 500px wide, I calculate 500 points), and then scale it to the window of the graph. Now, this works perfectly for most any line. However, it does not when dealing with asymptotes. If, when calculating points, the graph encounters a domain error (such as 1/0), the graph closes the shape in the Path2D.Double instance and starts a new line, so that the line looks mathematically correct. Example: However, because of the way it scales, sometimes it is rendered correctly, sometimes it isn't. When it isn't, the actual asymptotic line is shown, because within those 500 points, it skipped over x = 2.0 in the equation 1 / (x-2), and only did x = 1.98 and x = 2.04, which are perfectly valid in that equation. Example: In that case, I increased the window on the left and right one unit each. My question is: Is there a way to deal with asymptotes using this method of scaling so that the resulting line looks mathematically correct? I myself have thought of implementing a binary search-esque method, where, if it finds that it calculates one point, and then the next point is wildly far away from the last point, it searches in between those points for a domain error. I had trouble figuring out how to make it work in practice, however. Thank you for any help you may give!

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  • Detecting Singularities in a Graph

    - by nasufara
    I am creating a graphing calculator in Java as a project for my programming class. There are two main components to this calculator: the graph itself, which draws the line(s), and the equation evaluator, which takes in an equation as a String and... well, evaluates it. To create the line, I create a Path2D.Double instance, and loop through the points on the line. To do this, I calculate as many points as the graph is wide (e.g. if the graph itself is 500px wide, I calculate 500 points), and then scale it to the window of the graph. Now, this works perfectly for most any line. However, it does not when dealing with singularities. If, when calculating points, the graph encounters a domain error (such as 1/0), the graph closes the shape in the Path2D.Double instance and starts a new line, so that the line looks mathematically correct. Example: However, because of the way it scales, sometimes it is rendered correctly, sometimes it isn't. When it isn't, the actual asymptotic line is shown, because within those 500 points, it skipped over x = 2.0 in the equation 1 / (x-2), and only did x = 1.98 and x = 2.04, which are perfectly valid in that equation. Example: In that case, I increased the window on the left and right one unit each. My question is: Is there a way to deal with singularities using this method of scaling so that the resulting line looks mathematically correct? I myself have thought of implementing a binary search-esque method, where, if it finds that it calculates one point, and then the next point is wildly far away from the last point, it searches in between those points for a domain error. I had trouble figuring out how to make it work in practice, however. Thank you for any help you may give!

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  • Significance of Bresenhams Line of Sight algorithm

    - by GamDroid
    What is the significance of Bresenhams Line of Sight algorithm in chasing and evading in games? As far as i know and implemented this algorithm calulates the straight line between two given points. However while implementing it in game development i stored the points calculated using this algorithm in an array.Then im traversing this array for chasing and evading purpose. This looks to be working good with some angles only.In an pixel based environment/tile based. What if there are some obstacles added in the paths of the two points? then this algorithm will not work right? How well can we use the Bresenhams Line algorithm in game development?

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  • GRAPH PROBLEM: find an algorithm to determine the shortest path from one point to another in a recta

    - by newba
    I'm getting such an headache trying to elaborate an appropriate algorithm to go from a START position to a EXIT position in a maze. For what is worth, the maze is rectangular, maxsize 500x500 and, in theory, is resolvable by DFS with some branch and bound techniques ... 10 3 4 7 6 3 3 1 2 2 1 0 2 2 2 4 2 2 5 2 2 1 3 0 2 2 2 2 1 3 3 4 2 3 4 4 3 1 1 3 1 2 2 4 2 2 1 Output: 5 1 4 2 Explanation: Our agent looses energy every time he gives a step and he can only move UP, DOWN, LEFT and RIGHT. Also, if the agent arrives with a remaining energy of zero or less, he dies, so we print something like "Impossible". So, in the input 10 is the initial agent's energy, 3 4 is the START position (i.e. column 3, line 4) and we have a maze 7x6. Think this as a kind of labyrinth, in which I want to find the exit that gives the agent a better remaining energy (shortest path). In case there are paths which lead to the same remaining energy, we choose the one which has the small number of steps, of course. I need to know if a DFS to a maze 500x500 in the worst case is feasible with these limitations and how to do it, storing the remaining energy in each step and the number of steps taken so far. The output means the agent arrived with remaining energy= 5 to the exit pos 1 4 in 2 steps. If we look carefully, in this maze it's also possible to exit at pos 3 1 (column 3, row 1) with the same energy but with 3 steps, so we choose the better one. With these in mind, can someone help me some code or pseudo-code? I have troubles working this around with a 2D array and how to store the remaining energy, the path (or number of steps taken)....

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  • How to fit a custom graph to the boost graph library template?

    - by Michael
    I'm rusty on C++ templates and I'm using the boost graph library (a fatal combination). I've searched the web and can't find any direct instructions on how to take a custom graph structure and fit enough of it to BGL (boost graph library) that I can use boosts graph traversing algorithms. Anyone familiar enough with the library to help me out?

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  • C# graph library to be used from Unity3D

    - by Heisenbug
    I'm looking for a C# graph library to be used inside Unity3D script. I'm not looking for pathfinding libraries (I know there are good one available). I could consider using a path finding library only if it gives me direct access to underlying graph classes (I need nodes and edges, and classic graph algorithms) The only product I've seen that seems intersting is QuickGraph. I have the following question: Is it possible to use QuickGraph inside Unity3d? If yes. Is this a good idea? Does it have any drawbacks? Is it a quite fast and well written/supported library? Does anyone has ever used it? Are available other C# graph library that can be easily integrated in Unity3d?

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  • Scene Graph as Object Container?

    - by Bunkai.Satori
    Scene graph contains game nodes representing game objects. At a first glance, it might seem practical to use Scene Graph as physical container for in game objects, instead of std::vector< for example. My question is, is it practical to use Scene Graph to contain the game objects, or should it be used only to define scene objects/nodes linkages, while keepig the objects stored in separate container, such as std::vector<?

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  • Splitting Graph into distinct polygons in O(E) complexity

    - by Arthur Wulf White
    If you have seen my last question: trapped inside a Graph : Find paths along edges that do not cross any edges How do you split an entire graph into distinct shapes 'trapped' inside the graph(like the ones described in my last question) with good complexity? What I am doing now is iterating over all edges and then starting to traverse while always taking the rightmost turn. This does split the graph into distinct shapes. Then I eliminate all the excess shapes (that are repeats of previous shapes) and return the result. The complexity of this algorithm is O(E^2). I am wondering if I could do it in O(E) by removing edges I already traversed previously. My current implementation of that returns unexpected results.

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  • Problems with with A* algorithm

    - by V_Programmer
    I'm trying to implement the A* algorithm in Java. I followed this tutorial,in particular, this pseudocode: http://theory.stanford.edu/~amitp/GameProgramming/ImplementationNotes.html The problem is my code doesn't work. It goes into an infinite loop. I really don't know why this happens... I suspect that the problem are in F = G + H function implemented in Graph constructors. I suspect I am not calculate the neighbor F correclty. Here's my code: List<Graph> open; List<Graph> close; private void createRouteAStar(Unit u) { open = new ArrayList<Graph>(); close = new ArrayList<Graph>(); u.ai_route_endX = 11; u.ai_route_endY = 5; List<Graph> neigh; int index; int i; boolean finish = false; Graph current; int cost; Graph start = new Graph(u.xMap, u.yMap, 0, ManhattanDistance(u.xMap, u.yMap, u.ai_route_endX, u.ai_route_endY)); open.add(start); current = start; while(!finish) { index = findLowerF(); current = new Graph(open, index); System.out.println(current.x); System.out.println(current.y); if (current.x == u.ai_route_endX && current.y == u.ai_route_endY) { finish = true; } else { close.add(current); neigh = current.getNeighbors(); for (i = 0; i < neigh.size(); i++) { cost = current.g + ManhattanDistance(current.x, current.y, neigh.get(i).x, neigh.get(i).y); if (open.contains(neigh.get(i)) && cost < neigh.get(i).g) { open.remove(open.indexOf(neigh)); } else if (close.contains(neigh.get(i)) && cost < neigh.get(i).g) { close.remove(close.indexOf(neigh)); } else if (!open.contains(neigh.get(i)) && !close.contains(neigh.get(i))) { neigh.get(i).g = cost; neigh.get(i).f = cost + ManhattanDistance(neigh.get(i).x, neigh.get(i).y, u.ai_route_endX, u.ai_route_endY); neigh.get(i).setParent(current); open.add(neigh.get(i)); } } } } System.out.println("step"); for (i=0; i < close.size(); i++) { if (close.get(i).parent != null) { System.out.println(i); System.out.println(close.get(i).parent.x); System.out.println(close.get(i).parent.y); } } } private int findLowerF() { int i; int min = 10000; int minIndex = -1; for (i=0; i < open.size(); i++) { if (open.get(i).f < min) { min = open.get(i).f; minIndex = i; System.out.println("min"); System.out.println(min); } } return minIndex; } private int ManhattanDistance(int ax, int ay, int bx, int by) { return Math.abs(ax-bx) + Math.abs(ay-by); } And, as I've said. I suspect that the Graph class has the main problem. However I've not been able to detect and fix it. public class Graph { int x, y; int f,g,h; Graph parent; public Graph(int x, int y, int g, int h) { this.x = x; this.y = y; this.g = g; this.h = h; this.f = g + h; } public Graph(List<Graph> list, int index) { this.x = list.get(index).x; this.y = list.get(index).y; this.g = list.get(index).g; this.h = list.get(index).h; this.f = list.get(index).f; this.parent = list.get(index).parent; } public Graph(Graph gp) { this.x = gp.x; this.y = gp.y; this.g = gp.g; this.h = gp.h; this.f = gp.f; } public Graph(Graph gp, Graph parent) { this.x = gp.x; this.y = gp.y; this.g = gp.g; this.h = gp.h; this.f = g + h; this.parent = parent; } public List<Graph> getNeighbors() { List<Graph> aux = new ArrayList<Graph>(); aux.add(new Graph(x+1, y, g,h)); aux.add(new Graph(x-1, y, g,h)); aux.add(new Graph(x, y+1, g,h)); aux.add(new Graph(x, y-1, g,h)); return aux; } public void setParent(Graph g) { parent = g; } } Little Edit: Using the System.out and the Debugger I discovered that the program ALWAYS is check the same "current" graph, (15,8) which is the (u.xMap, u.yMap) position. Looks like it keeps forever in the first step.

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  • Facebook Graph API authentication in canvas app and track session

    - by cdpnet
    Short question is: how can i use graph api oauth redirects mechanism to authenticate user and save retrieved access_token and also use javascript SDK when needed (the problem is javascript SDK will have different access_token when initialized). I have initially setup my facebook iframe canvas app, with single sign on. This works well with graph api, as I am able to use access_token saved by facebook's javascript when it detects sessionchange(user logged in). But, I want to rather not do single sign-on. But, use graph api redirect and force user to send to a permissions dialog. But, if he has already given permissions, I shouldn't redirect user. How to handle this? Another question: I have done graph api redirects for authentication and have retrieved access_token also. But then, what if I want to use javascript call FB.ui to do stream.Publish? I think it will use it's own access_token which is set during FB.init and detecting session. So, I am looking for some path here. How to use graph api for authentication and also use facebook's javascript SDK when needed. P.S. I'm using ASP .NET MVC 2. I have an authentication filter developed, which needs to detect the user's authentication state and redirect.(currently it does this to graph api authorize url)

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  • A two way minimum spanning tree of a directed graph

    - by mvid
    Given a directed graph with weighted edges, what algorithm can be used to give a sub-graph that has minimum weight, but allows movement from any vertex to any other vertex in the graph (under the assumption that paths between any two vertices always exist). Does such an algorithm exist?

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  • The best algorithm enhancing alpha-beta?

    - by Risa
    I'm studying AI. My teacher gave us source code of a chess-like game and asked us to enhance it. My exercise is to improve the alpha/beta algorithm implementing in that game. The programmer already uses transposition tables, MTD(f) with alpha/beta+memory (MTD(f) is the best algorithm I know by far). So is there any better algorithm to enhance alpha-beta search or a good way to implement MTD(f) in coding a game?

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  • Make my website dynamically loaded data available to Facebook Open Graph Object Scrapper

    - by fvaliquette
    Here is the design of my web site: The user enter myWebsite.com/a/1 .htaccess rules redirect to myWebsite.com/b Now the JavaScript ExtJS library is loading. Extracting the value from the URL (in this case it is “1”) Loading ./xml/1.xml From 1.xml setting the Open Graph data (Title, type, image, etc) Loading data that will be shown to the user from 1.xml into the website. My question is: How can I make the Open Graph data available to Facebook? Facebook do not to load my ExtJS JavaScript Library before extracting the Open Graph Object values from the HTML. Is there an easy solution to this problem? The only solutions I found is to make statics web pages or dynamically pages rendered on the server side but I would like to avoid these since my web page implementation is already finished and I would like to avoid re working on it.

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  • Updating scene graph in multithreaded game

    - by user782220
    In a game with a render thread and a game logic thread the game logic thread needs to update the scene graph used by the render thread. I've read about ideas such as a queue of updates. Can someone describe to a newbie at scene graphs what kind of interface the scene graph exports. Presumably it would be rather complicated. So then how does a queue of updates get implemented in C++ in a way that can handle the complexity of the interface of the scene graph while also being type safe and efficient. Again I'm a newbie at scene graphs and C++.

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