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  • what is mistakes/errors in this code c++ tell me the correction ??

    - by jeje
    hello all here in this code the compiler print error : 132 C:.... `createlist' undeclared (first use this function) (Each undeclared identifier is reported only once for each function it appears in.) and repeat it again in all calls in main function :( what's the problem ?? plzzzz help me #include<iostream> #include<string> using namespace std; template <typename T> struct Node { T num; struct Node<T> *next; // to craet list nodes void createlist(Node<T> *p) { T data; for( ; ; ) // its containue until user want to stop { cout<<"enter data number or '#' to stop\n"; cin>>data; if(data == '#') { p->next =NULL; break; } else { p->num= data; p->next = new Node<T>; p=p->next; } } } //count list to use it in sort function int countlist (Node<T> *p) { int count=0; while(p->next != NULL) { count++; p=p->next; } return count; } // sort list void sort( Node<T> *p) { Node<T> *p1, *p2; //element 1 & 2 to compare between them int i, j , n; T temp; n= countlist(p); for( i=1; i<n ; i++) { // here every loop time we put the first element in list in p1 and the second in p2 p1=p; p2=p->next; for(j=1; j<=(n-i) ; j++) { if( p1->num > p2->num) { temp=p2->num; p2->num=p1->num; p1->num=temp; } } p1= p1->next; p2= p2->next; } } //add new number in any location the user choose void insertatloc(Node<T> *p) { T n; //read new num int loc; //read the choosen location Node<T> *locadd, *newnum, *temp; cout <<" enter location you want ..! \n"; cin>>loc; locadd=NULL; //make it null to checked if there is location after read it from user ot not while(p->next !=NULL) { if( p->next==loc) { locadd=p; break; } p=p->next; } if (locadd==NULL) {cout<<" cannot find the location\n";} else //if location is right {cout<<" enter new number\n"; // new number to creat also new location for it cin>>n; newnum= new Node/*<T>*/; newnum->num=n; temp= locadd->next; locadd->next=newnum; newnum->next=temp; } locadd->num=sort(locadd); // call sort function } // display all list nodes void displaylist (Node<T> *p) { while (p->next != NULL) { cout<<" the list contain:\n"; cout<<p->num<<endl; p=p->next; } } };//end streuct int main() { cout<<"*** Welcome in Linked List Sheet 2****\n"; // defined pointer for structer Node // that value is the address of first node struct Node<int>*mynodes= new struct Node<int>; // create nodes in mynodes list cout<<"\nCreate nodes in list"; createlist(mynodes); // insert node in location insertatloc(mynodes); /* count the number of all nodes nodescount = countlist(mynodes); cout<<"\nThe number of nodes in list is: "<<nodescount;*/ // sort nodes in list sort(mynodes); // Display nodes cout<<"\nDisplay all nodes in list:\n"; displaylist(mynodes); system("pause"); return 0; }

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  • Is Berkeley DB a NoSQL solution?

    - by Gregory Burd
    Berkeley DB is a library. To use it to store data you must link the library into your application. You can use most programming languages to access the API, the calls across these APIs generally mimic the Berkeley DB C-API which makes perfect sense because Berkeley DB is written in C. The inspiration for Berkeley DB was the DBM library, a part of the earliest versions of UNIX written by AT&T's Ken Thompson in 1979. DBM was a simple key/value hashtable-based storage library. In the early 1990s as BSD UNIX was transitioning from version 4.3 to 4.4 and retrofitting commercial code owned by AT&T with unencumbered code, it was the future founders of Sleepycat Software who wrote libdb (aka Berkeley DB) as the replacement for DBM. The problem it addressed was fast, reliable local key/value storage. At that time databases almost always lived on a single node, even the most sophisticated databases only had simple fail-over two node solutions. If you had a lot of data to store you would choose between the few commercial RDBMS solutions or to write your own custom solution. Berkeley DB took the headache out of the custom approach. These basic market forces inspired other DBM implementations. There was the "New DBM" (ndbm) and the "GNU DBM" (GDBM) and a few others, but the theme was the same. Even today TokyoCabinet calls itself "a modern implementation of DBM" mimicking, and improving on, something first created over thirty years ago. In the mid-1990s, DBM was the name for what you needed if you were looking for fast, reliable local storage. Fast forward to today. What's changed? Systems are connected over fast, very reliable networks. Disks are cheep, fast, and capable of storing huge amounts of data. CPUs continued to follow Moore's Law, processing power that filled a room in 1990 now fits in your pocket. PCs, servers, and other computers proliferated both in business and the personal markets. In addition to the new hardware entire markets, social systems, and new modes of interpersonal communication moved onto the web and started evolving rapidly. These changes cause a massive explosion of data and a need to analyze and understand that data. Taken together this resulted in an entirely different landscape for database storage, new solutions were needed. A number of novel solutions stepped up and eventually a category called NoSQL emerged. The new market forces inspired the CAP theorem and the heated debate of BASE vs. ACID. But in essence this was simply the market looking at what to trade off to meet these new demands. These new database systems shared many qualities in common. There were designed to address massive amounts of data, millions of requests per second, and scale out across multiple systems. The first large-scale and successful solution was Dynamo, Amazon's distributed key/value database. Dynamo essentially took the next logical step and added a twist. Dynamo was to be the database of record, it would be distributed, data would be partitioned across many nodes, and it would tolerate failure by avoiding single points of failure. Amazon did this because they recognized that the majority of the dynamic content they provided to customers visiting their web store front didn't require the services of an RDBMS. The queries were simple, key/value look-ups or simple range queries with only a few queries that required more complex joins. They set about to use relational technology only in places where it was the best solution for the task, places like accounting and order fulfillment, but not in the myriad of other situations. The success of Dynamo, and it's design, inspired the next generation of Non-SQL, distributed database solutions including Cassandra, Riak and Voldemort. The problem their designers set out to solve was, "reliability at massive scale" so the first focal point was distributed database algorithms. Underneath Dynamo there is a local transactional database; either Berkeley DB, Berkeley DB Java Edition, MySQL or an in-memory key/value data structure. Dynamo was an evolution of local key/value storage onto networks. Cassandra, Riak, and Voldemort all faced similar design decisions and one, Voldemort, choose Berkeley DB Java Edition for it's node-local storage. Riak at first was entirely in-memory, but has recently added write-once, append-only log-based on-disk storage similar type of storage as Berkeley DB except that it is based on a hash table which must reside entirely in-memory rather than a btree which can live in-memory or on disk. Berkeley DB evolved too, we added high availability (HA) and a replication manager that makes it easy to setup replica groups. Berkeley DB's replication doesn't partitioned the data, every node keeps an entire copy of the database. For consistency, there is a single node where writes are committed first - a master - then those changes are delivered to the replica nodes as log records. Applications can choose to wait until all nodes are consistent, or fire and forget allowing Berkeley DB to eventually become consistent. Berkeley DB's HA scales-out quite well for read-intensive applications and also effectively eliminates the central point of failure by allowing replica nodes to be elected (using a PAXOS algorithm) to mastership if the master should fail. This implementation covers a wide variety of use cases. MemcacheDB is a server that implements the Memcache network protocol but uses Berkeley DB for storage and HA to replicate the cache state across all the nodes in the cache group. Google Accounts, the user authentication layer for all Google properties, was until recently running Berkeley DB HA. That scaled to a globally distributed system. That said, most NoSQL solutions try to partition (shard) data across nodes in the replication group and some allow writes as well as reads at any node, Berkeley DB HA does not. So, is Berkeley DB a "NoSQL" solution? Not really, but it certainly is a component of many of the existing NoSQL solutions out there. Forgetting all the noise about how NoSQL solutions are complex distributed databases when you boil them down to a single node you still have to store the data to some form of stable local storage. DBMs solved that problem a long time ago. NoSQL has more to do with the layers on top of the DBM; the distributed, sometimes-consistent, partitioned, scale-out storage that manage key/value or document sets and generally have some form of simple HTTP/REST-style network API. Does Berkeley DB do that? Not really. Is Berkeley DB a "NoSQL" solution today? Nope, but it's the most robust solution on which to build such a system. Re-inventing the node-local data storage isn't easy. A lot of people are starting to come to appreciate the sophisticated features found in Berkeley DB, even mimic them in some cases. Could Berkeley DB grow into a NoSQL solution? Absolutely. Our key/value API could be extended over the net using any of a number of existing network protocols such as memcache or HTTP/REST. We could adapt our node-local data partitioning out over replicated nodes. We even have a nice query language and cost-based query optimizer in our BDB XML product that we could reuse were we to build out a document-based NoSQL-style product. XML and JSON are not so different that we couldn't adapt one to work with the other interchangeably. Without too much effort we could add what's missing, we could jump into this No SQL market withing a single product development cycle. Why isn't Berkeley DB already a NoSQL solution? Why aren't we working on it? Why indeed...

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  • The SPARC SuperCluster

    - by Karoly Vegh
    Oracle has been providing a lead in the Engineered Systems business for quite a while now, in accordance with the motto "Hardware and Software Engineered to Work Together." Indeed it is hard to find a better definition of these systems.  Allow me to summarize the idea. It is:  Build a compute platform optimized to run your technologies Develop application aware, intelligently caching storage components Take an impressively fast network technology interconnecting it with the compute nodes Tune the application to scale with the nodes to yet unseen performance Reduce the amount of data moving via compression Provide this all in a pre-integrated single product with a single-pane management interface All these ideas have been around in IT for quite some time now. The real Oracle advantage is adding the last one to put these all together. Oracle has built quite a portfolio of Engineered Systems, to run its technologies - and run those like they never ran before. In this post I'll focus on one of them that serves as a consolidation demigod, a multi-purpose engineered system.  As you probably have guessed, I am talking about the SPARC SuperCluster. It has many great features inherited from its predecessors, and it adds several new ones. Allow me to pick out and elaborate about some of the most interesting ones from a technological point of view.  I. It is the SPARC SuperCluster T4-4. That is, as compute nodes, it includes SPARC T4-4 servers that we learned to appreciate and respect for their features: The SPARC T4 CPUs: Each CPU has 8 cores, each core runs 8 threads. The SPARC T4-4 servers have 4 sockets. That is, a single compute node can in parallel, simultaneously  execute 256 threads. Now, a full-rack SPARC SuperCluster has 4 of these servers on board. Remember the keyword demigod.  While retaining the forerunner SPARC T3's exceptional throughput, the SPARC T4 CPUs raise the bar with single performance too - a humble 5x better one than their ancestors.  actually, the SPARC T4 CPU cores run in both single-threaded and multi-threaded mode, and switch between these two on-the-fly, fulfilling not only single-threaded OR multi-threaded applications' needs, but even mixed requirements (like in database workloads!). Data security, anyone? Every SPARC T4 CPU core has a built-in encryption engine, that is, encryption algorithms cast into silicon.  A PCI controller right on the chip for customers who need I/O performance.  Built-in, no-cost Virtualization:  Oracle VM for SPARC (the former LDoms or Logical Domains) is not a server-emulation virtualization technology but rather a serverpartitioning one, the hypervisor runs in the server firmware, and all the VMs' HW resources (I/O, CPU, memory) are accessed natively, without performance overhead.  This enables customers to run a number of Solaris 10 and Solaris 11 VMs separated, independent of each other within a physical server II. For Database performance, it includes Exadata Storage Cells - one of the main reasons why the Exadata Database Machine performs at diabolic speed. What makes them important? They provide DB backend storage for your Oracle Databases to run on the SPARC SuperCluster, that is what they are built and tuned for DB performance.  These storage cells are SQL-aware.  That is, if a SPARC T4 database compute node executes a query, it doesn't simply request tons of raw datablocks from the storage, filters the received data, and throws away most of it where the statement doesn't apply, but provides the SQL query to the storage node too. The storage cell software speaks SQL, that is, it is able to prefilter and through that transfer only the relevant data. With this, the traffic between database nodes and storage cells is reduced immensely. Less I/O is a good thing - as they say, all the CPUs of the world do one thing just as fast as any other - and that is waiting for I/O.  They don't only pre-filter, but also provide data preprocessing features - e.g. if a DB-node requests an aggregate of data, they can calculate it, and handover only the results, not the whole set. Again, less data to transfer.  They support the magical HCC, (Hybrid Columnar Compression). That is, data can be stored in a precompressed form on the storage. Less data to transfer.  Of course one can't simply rely on disks for performance, there is Flash Storage included there for caching.  III. The low latency, high-speed backbone network: InfiniBand, that interconnects all the members with: Real High Speed: 40 Gbit/s. Full Duplex, of course. Oh, and a really low latency.  RDMA. Remote Direct Memory Access. This technology allows the DB nodes to do exactly that. Remotely, directly placing SQL commands into the Memory of the storage cells. Dodging all the network-stack bottlenecks, avoiding overhead, placing requests directly into the process queue.  You can also run IP over InfiniBand if you please - that's the way the compute nodes can communicate with each other.  IV. Including a general-purpose storage too: the ZFSSA, which is a unified storage, providing NAS and SAN access too, with the following features:  NFS over RDMA over InfiniBand. Nothing is faster network-filesystem-wise.  All the ZFS features onboard, hybrid storage pools, compression, deduplication, snapshot, replication, NFS and CIFS shares Storageheads in a HA-Cluster configuration providing availability of the data  DTrace Live Analytics in a web-based Administration UI Being a general purpose application data storage for your non-database applications running on the SPARC SuperCluster over whichever protocol they prefer, easily replicating, snapshotting, cloning data for them.  There's a lot of great technology included in Oracle's SPARC SuperCluster, we have talked its interior through. As for external scalability: you can start with a half- of full- rack SPARC SuperCluster, and scale out to several racks - that is, stacking not separate full-rack SPARC SuperClusters, but extending always one large instance of the size of several full-racks. Yes, over InfiniBand network. Add racks as you grow.  What technologies shall run on it? SPARC SuperCluster is a general purpose scaleout consolidation/cloud environment. You can run Oracle Databases with RAC scaling, or Oracle Weblogic (end enjoy the SPARC T4's advantages to run Java). Remember, Oracle technologies have been integrated with the Oracle Engineered Systems - this is the Oracle on Oracle advantage. But you can run other software environments such as SAP if you please too. Run any application that runs on Oracle Solaris 10 or Solaris 11. Separate them in Virtual Machines, or even Oracle Solaris Zones, monitor and manage those from a central UI. Here the key takeaways once again: The SPARC SuperCluster: Is a pre-integrated Engineered System Contains SPARC T4-4 servers with built-in virtualization, cryptography, dynamic threading Contains the Exadata storage cells that intelligently offload the burden of the DB-nodes  Contains a highly available ZFS Storage Appliance, that provides SAN/NAS storage in a unified way Combines all these elements over a high-speed, low-latency backbone network implemented with InfiniBand Can grow from a single half-rack to several full-rack size Supports the consolidation of hundreds of applications To summarize: All these technologies are great by themselves, but the real value is like in every other Oracle Engineered System: Integration. All these technologies are tuned to perform together. Together they are way more than the sum of all - and a careful and actually very time consuming integration process is necessary to orchestrate all these for performance. The SPARC SuperCluster's goal is to enable infrastructure operations and offer a pre-integrated solution that can be architected and delivered in hours instead of months of evaluations and tests. The tedious and most importantly time and resource consuming part of the work - testing and evaluating - has been done.  Now go, provide services.   -- charlie  

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  • How-to delete a tree node using the context menu

    - by frank.nimphius
    Hierarchical trees in Oracle ADF make use of View Accessors, which means that only the top level node needs to be exposed as a View Object instance on the ADF Business Components Data Model. This also means that only the top level node has a representation in the PageDef file as a tree binding and iterator binding reference. Detail nodes are accessed through tree rule definitions that use the accessor mentioned above (or nested collections in the case of POJO or EJB business services). The tree component is configured for single node selection, which however can be declaratively changed for users to press the ctrl key and selecting multiple nodes. In the following, I explain how to create a context menu on the tree for users to delete the selected tree nodes. For this, the context menu item will access a managed bean, which then determines the selected node(s), the internal ADF node bindings and the rows they represent. As mentioned, the ADF Business Components Data Model only needs to expose the top level node data sources, which in this example is an instance of the Locations View Object. For the tree to work, you need to have associations defined between entities, which usually is done for you by Oracle JDeveloper if the database tables have foreign keys defined Note: As a general hint of best practices and to simplify your life: Make sure your database schema is well defined and designed before starting your development project. Don't treat the database as something organic that grows and changes with the requirements as you proceed in your project. Business service refactoring in response to database changes is possible, but should be treated as an exception, not the rule. Good database design is a necessity – even for application developers – and nothing evil. To create the tree component, expand the Data Controls panel and drag the View Object collection to the view. From the context menu, select the tree component entry and continue with defining the tree rules that make up the hierarchical structure. As you see, when pressing the green plus icon  in the Edit Tree Binding  dialog, the data structure, Locations -  Departments – Employees in my sample, shows without you having created a View Object instance for each of the nodes in the ADF Business Components Data Model. After you configured the tree structure in the Edit Tree Binding dialog, you press OK and the tree is created. Select the tree in the page editor and open the Structure Window (ctrl+shift+S). In the Structure window, expand the tree node to access the conextMenu facet. Use the right mouse button to insert a Popup  into the facet. Repeat the same steps to insert a Menu and a Menu Item into the Popup you created. The Menu item text should be changed to something meaningful like "Delete". Note that the custom menu item later is added to the context menu together with the default context menu options like expand and expand all. To define the action that is executed when the menu item is clicked on, you select the Action Listener property in the Property Inspector and click the arrow icon followed by the Edit menu option. Create or select a managed bean and define a method name for the action handler. Next, select the tree component and browse to its binding property in the Property Inspector. Again, use the arrow icon | Edit option to create a component binding in the same managed bean that has the action listener defined. The tree handle is used in the action listener code, which is shown below: public void onTreeNodeDelete(ActionEvent actionEvent) {   //access the tree from the JSF component reference created   //using the af:tree "binding" property. The "binding" property   //creates a pair of set/get methods to access the RichTree instance   RichTree tree = this.getTreeHandler();   //get the list of selected row keys   RowKeySet rks = tree.getSelectedRowKeys();   //access the iterator to loop over selected nodes   Iterator rksIterator = rks.iterator();          //The CollectionModel represents the tree model and is   //accessed from the tree "value" property   CollectionModel model = (CollectionModel) tree.getValue();   //The CollectionModel is a wrapper for the ADF tree binding   //class, which is JUCtrlHierBinding   JUCtrlHierBinding treeBinding =                  (JUCtrlHierBinding) model.getWrappedData();          //loop over the selected nodes and delete the rows they   //represent   while(rksIterator.hasNext()){     List nodeKey = (List) rksIterator.next();     //find the ADF node binding using the node key     JUCtrlHierNodeBinding node =                       treeBinding.findNodeByKeyPath(nodeKey);     //delete the row.     Row rw = node.getRow();       rw.remove();   }          //only refresh the tree if tree nodes have been selected   if(rks.size() > 0){     AdfFacesContext adfFacesContext =                          AdfFacesContext.getCurrentInstance();     adfFacesContext.addPartialTarget(tree);   } } Note: To enable multi node selection for a tree, select the tree and change the row selection setting from "single" to "multiple". Note: a fully pictured version of this post will become available at the end of the month in a PDF summary on ADF Code Corner : http://www.oracle.com/technetwork/developer-tools/adf/learnmore/index-101235.html 

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  • Converting "A* Search" code from C++ to Java [on hold]

    - by mr5
    Updated! I get this code from this site It's A* Search Algorithm(finding shortest path with heuristics) I modify most of variable names and some if conditions from the original version to satisfy my syntactic taste. It works in C++ (as I can't see any trouble with it) but fails in Java version. Java Code: String findPath(int startX, int startY, int finishX, int finishY) { @SuppressWarnings("unchecked") LinkedList<Node>[] nodeList = (LinkedList<Node>[]) new LinkedList<?>[2]; nodeList[0] = new LinkedList<Node>(); nodeList[1] = new LinkedList<Node>(); Node n0; Node m0; int nlIndex = 0; // queueList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = new Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[nlIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[nlIndex].isEmpty() ) { LinkedList<Node> pq = nodeList[nlIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = new Node( pq.peek().getX(), pq.peek().getY(), pq.peek().getIterCount(), pq.peek().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[nlIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions String path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; int c = '0' + ( j + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; path = (char)c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < Node.DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!(xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( gridMap.getData( ydy, xdx ) == GridMap.WALKABLE || gridMap.getData( ydy, xdx ) == GridMap.FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = new Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[nlIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; // replace the node // by emptying one queueList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while( !(nodeList[nlIndex].peek().getX() == xdx && nodeList[nlIndex].peek().getY() == ydy ) ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nodeList[nlIndex].pop(); // remove the wanted node // empty the larger size queueList to the smaller one if( nodeList[nlIndex].size() > nodeList[ 1 - nlIndex ].size() ) nlIndex = 1 - nlIndex; while( !nodeList[nlIndex].isEmpty() ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nlIndex = 1 - nlIndex; nodeList[nlIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output1: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Misleading path) Output2: Changing these lines: n0 = new Node( a, b, c, d ); m0 = new Node( e, f, g, h ); to n0.set( a, b, c, d ); m0.set( e, f, g, h ); I get (I'm really confused) C++ Code: std::string A_Star::findPath(int startX, int startY, int finishX, int finishY) { typedef std::queue<Node> List_Container; List_Container nodeList[2]; // list of open (not-yet-tried) nodes Node n0; Node m0; int pqIndex = 0; // nodeList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[pqIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[pqIndex].empty() ) { List_Container &pq = nodeList[pqIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = Node( pq.front().getX(), pq.front().getY(), pq.front().getIterCount(), pq.front().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[pqIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions std::string path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; char c = '0' + ( j + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; path = c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!( xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( pGrid->getData(ydy,xdx) == WALKABLE || pGrid->getData(ydy, xdx) == FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[pqIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; // replace the node // by emptying one nodeList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while ( !( nodeList[pqIndex].front().getX() == xdx && nodeList[pqIndex].front().getY() == ydy ) ) { nodeList[1 - pqIndex].push( nodeList[pqIndex].front() ); nodeList[pqIndex].pop(); } nodeList[pqIndex].pop(); // remove the wanted node // empty the larger size nodeList to the smaller one if( nodeList[pqIndex].size() > nodeList[ 1 - pqIndex ].size() ) pqIndex = 1 - pqIndex; while( !nodeList[pqIndex].empty() ) { nodeList[1-pqIndex].push(nodeList[pqIndex].front()); nodeList[pqIndex].pop(); } pqIndex = 1 - pqIndex; nodeList[pqIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Just right) From what I read about Java's documentation, I came up with the conclusion: C++'s std::queue<T>::front() == Java's LinkedList<T>.peek() Java's LinkedList<T>.pop() == C++'s std::queue<T>::front() + std::queue<T>::pop() What might I be missing in my Java version? In what way does it became different algorithmically from the C++ version?

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  • How to configure a zone cluster on Solaris Cluster 4.0

    - by JuergenS
    This is a short overview on how to configure a zone cluster on Solaris Cluster 4.0. This is a little bit different as in Solaris Cluster 3.2/3.3 because Solaris Cluster 4.0 is only running on Solaris 11. The name of the zone cluster must be unique throughout the global Solaris Cluster and must be configured on a global Solaris Cluster. Please read all the requirements for zone cluster in Solaris Cluster Software Installation Guide for SC4.0. For Solaris Cluster 3.2/3.3 please refer to my previous blog Configuration steps to create a zone cluster in Solaris Cluster 3.2/3.3. A. Configure the zone cluster into the already running global clusterCheck if zone cluster can be created # cluster show-netprops to change number of zone clusters use # cluster set-netprops -p num_zoneclusters=12 Note: 12 zone clusters is the default, values can be customized! Create config file (zc1config) for zone cluster setup e.g: Configure zone cluster # clzc configure -f zc1config zc1 Note: If not using the config file the configuration can also be done manually # clzc configure zc1 Check zone configuration # clzc export zc1 Verify zone cluster # clzc verify zc1 Note: The following message is a notice and comes up on several clzc commands Waiting for zone verify commands to complete on all the nodes of the zone cluster "zc1"... Install the zone cluster # clzc install zc1 Note: Monitor the consoles of the global zone to see how the install proceed! (The output is different on the nodes) It's very important that all global cluster nodes have installed the same set of ha-cluster packages! Boot the zone cluster # clzc boot zc1 Login into non-global-zones of zone cluster zc1 on all nodes and finish Solaris installation. # zlogin -C zc1 Check status of zone cluster # clzc status zc1 Login into non-global-zones of zone cluster zc1 and configure the shell environment for root (for PATH: /usr/cluster/bin, for MANPATH: /usr/cluster/man) # zlogin -C zc1 If using additional name service configure /etc/nsswitch.conf of zone cluster non-global zones. hosts: cluster files netmasks: cluster files Configure /etc/inet/hosts of the zone cluster zones Enter all the logical hosts of non-global zones B. Add resource groups and resources to zone cluster Create a resource group in zone cluster # clrg create -n <zone-hostname-node1>,<zone-hostname-node2> app-rg Note1: Use command # cluster status for zone cluster resource group overview. Note2: You can also run all commands for zone cluster in global cluster by adding the option -Z to the command. e.g: # clrg create -Z zc1 -n <zone-hostname-node1>,<zone-hostname-node2> app-rg Set up the logical host resource for zone cluster In the global zone do: # clzc configure zc1 clzc:zc1 add net clzc:zc1:net set address=<zone-logicalhost-ip> clzc:zc1:net end clzc:zc1 commit clzc:zc1 exit Note: Check that logical host is in /etc/hosts file In zone cluster do: # clrslh create -g app-rg -h <zone-logicalhost> <zone-logicalhost>-rs Set up storage resource for zone cluster Register HAStoragePlus # clrt register SUNW.HAStoragePlus Example1) ZFS storage pool In the global zone do: Configure zpool eg: # zpool create <zdata> mirror cXtXdX cXtXdX and # clzc configure zc1 clzc:zc1 add dataset clzc:zc1:dataset set name=zdata clzc:zc1:dataset end clzc:zc1 verify clzc:zc1 commit clzc:zc1 exit Check setup with # clzc show -v zc1 In the zone cluster do: # clrs create -g app-rg -t SUNW.HAStoragePlus -p zpools=zdata app-hasp-rs Example2) HA filesystem In the global zone do: Configure SVM diskset and SVM devices. and # clzc configure zc1 clzc:zc1 add fs clzc:zc1:fs set dir=/data clzc:zc1:fs set special=/dev/md/datads/dsk/d0 clzc:zc1:fs set raw=/dev/md/datads/rdsk/d0 clzc:zc1:fs set type=ufs clzc:zc1:fs add options [logging] clzc:zc1:fs end clzc:zc1 verify clzc:zc1 commit clzc:zc1 exit Check setup with # clzc show -v zc1 In the zone cluster do: # clrs create -g app-rg -t SUNW.HAStoragePlus -p FilesystemMountPoints=/data app-hasp-rs Example3) Global filesystem as loopback file system In the global zone configure global filesystem and it to /etc/vfstab on all global nodes e.g.: /dev/md/datads/dsk/d0 /dev/md/datads/dsk/d0 /global/fs ufs 2 yes global,logging and # clzc configure zc1 clzc:zc1 add fs clzc:zc1:fs set dir=/zone/fs (zc-lofs-mountpoint) clzc:zc1:fs set special=/global/fs (globalcluster-mountpoint) clzc:zc1:fs set type=lofs clzc:zc1:fs end clzc:zc1 verify clzc:zc1 commit clzc:zc1 exit Check setup with # clzc show -v zc1 In the zone cluster do: (Create scalable rg if not already done) # clrg create -p desired_primaries=2 -p maximum_primaries=2 app-scal-rg # clrs create -g app-scal-rg -t SUNW.HAStoragePlus -p FilesystemMountPoints=/zone/fs hasp-rs More details of adding storage available in the Installation Guide for zone cluster Switch resource group and resources online in the zone cluster # clrg online -eM app-rg # clrg online -eM app-scal-rg Test: Switch of the resource group in the zone cluster # clrg switch -n zonehost2 app-rg # clrg switch -n zonehost2 app-scal-rg Add supported dataservice to zone cluster Documentation for SC4.0 is available here Example output: Appendix: To delete a zone cluster do: # clrg delete -Z zc1 -F + Note: Zone cluster uninstall can only be done if all resource groups are removed in the zone cluster. The command 'clrg delete -F +' can be used in zone cluster to delete the resource groups recursively. # clzc halt zc1 # clzc uninstall zc1 Note: If clzc command is not successful to uninstall the zone, then run 'zoneadm -z zc1 uninstall -F' on the nodes where zc1 is configured # clzc delete zc1

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  • Oracle Enterprise Manager Ops Center 12c : Enterprise Controller High Availability (EC HA)

    - by Anand Akela
    Contributed by Mahesh sharma, Oracle Enterprise Manager Ops Center team In Oracle Enterprise Manager Ops Center 12c we introduced a new feature to make the Enterprise Controllers highly available. With EC HA if the hardware crashes, or if the Enterprise Controller services and/or the remote database stop responding, then the enterprise services are immediately restarted on the other standby Enterprise Controller without administrative intervention. In today's post, I'll briefly describe EC HA, look at some of the prerequisites and then show some screen shots of how the Enterprise Controller is represented in the BUI. In my next post, I'll show you how to install the EC in a HA environment and some of the new commands. What is EC HA? Enterprise Controller High Availability (EC HA) provides an active/standby fail-over solution for two or more Ops Center Enterprise Controllers, all within an Oracle Clusterware framework. This allows EC resources to relocate to a standby if the hardware crashes, or if certain services fail. It is also possible to manually relocate the services if maintenance on the active EC is required. When the EC services are relocated to the standby, EC services are interrupted only for the period it takes for the EC services to stop on the active node and to start back up on a standby node. What are the prerequisites? To install EC in a HA framework an understanding of the prerequisites are required. There are many possibilities on how these prerequisites can be installed and configured - we will not discuss these in this post. However, best practices should be applied when installing and configuring, I would suggest that you get expert help if you are not familiar with them. Lets briefly look at each of these prerequisites in turn: Hardware : Servers are required to host the active and standby node(s). As the nodes will be in a clustered environment, they need to be the same model and configured identically. The nodes should have the same processor class, number of cores, memory, network cards, for example. Operating System : We can use Solaris 10 9/10 or higher, Solaris 11, OEL 5.5 or higher on x86 or Sparc Network : There are a number of requirements for network cards in clusterware, and cables should be networked identically on all the nodes. We must also consider IP allocation for public / private and Virtual IP's (VIP's). Storage : Shared storage will be required for the cluster voting disks, Oracle Cluster Register (OCR) and the EC's libraries. Clusterware : Oracle Clusterware version 11.2.0.3 or later is required. This can be downloaded from: http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html Remote Database : Oracle RDBMS 11.1.0.x or later is required. This can be downloaded from: http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html For detailed information on how to install EC HA , please read : http://docs.oracle.com/cd/E27363_01/doc.121/e25140/install_config-shared.htm#OPCSO242 For detailed instructions on installing Oracle Clusterware, please read : http://docs.oracle.com/cd/E11882_01/install.112/e17214/chklist.htm#BHACBGII For detailed instructions on installing the remote Oracle database have a read of: http://www.oracle.com/technetwork/database/enterprise-edition/documentation/index.html The schematic diagram below gives a visual view of how the prerequisites are connected. When a fail-over occurs the Enterprise Controller resources and the VIP are relocated to one of the standby nodes. The standby node then becomes active and all Ops Center services are resumed. Connecting to the Enterprise Controller from your favourite browser. Let's presume we have installed and configured all the prerequisites, and installed Ops Center on the active and standby nodes. We can now connect to the active node from a browser i.e. http://<active_node1>/, this will redirect us to the virtual IP address (VIP). The VIP is the IP address that moves with the Enterprise Controller resource. Once you log on and view the assets, you will see some new symbols, these represent that the nodes are cluster members, with one being an active member and the other a standby member in this case. If you connect to the standby node, the browser will redirect you to a splash page, indicating that you have connected to the standby node. Hope you find this topic interesting. Next time I will post about how to install the Enterprise Controller in the HA frame work. Stay Connected: Twitter |  Face book |  You Tube |  Linked in |  Newsletter

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  • GlassFish Clustering with DCOM on Windows

    - by ByronNevins
    DCOM - Distributed COM, a Microsoft protocol for communicating with Windows machines. Why use DCOM? In GlassFish 3.1 SSH is used as the standard way to run commands on remote nodes for clustering.  It is very difficult for users to get SSH configured properly on Windows.  SSH does not come with Windows so we have to depend on third party tools.  And then the user is forced to install and configure these tools -- which can be tricky. DCOM is available on all supported platforms.  It is built-in to Windows. The idea is to use DCOM to communicate with remote Windows nodes.  This has the huge advantage that the user has to do minimal, if any, configuration on the Windows nodes. Implementation HighlightsTwo open Source Libraries have been added to GlassFish: Jcifs – a SAMBA implementation in Java J-interop – A Java implementation for making DCOM calls to remote Windows computers.   Note that any supported platform can use DCOM to work with Windows nodes -- not just Windows.E.g. you can have a Linux DAS work with Windows remote instances.All existing SSH commands now have a corresponding DCOM command – except for setup-ssh which isn’t needed for DCOM.  validate-dcom is an all new command. New DCOM Commands create-node-dcom delete-node-dcom install-node-dcom list-nodes-dcom ping-node-dcom uninstall-node-dcom update-node-dcom validate-dcom setup-local-dcom (This is only available via Update Center for GlassFish 3.1.2) These commands are in-place in the trunk (4.0).  And in the branch (3.1.2) Windows Configuration Challenges There are an infinite number of possible configurations of Windows if you look at it as a combination of main release, service-pack, special drivers, software, configuration etc.  Later versions of Windows err on the side of tightening security be default.  This means that the Windows host may need to have configuration changes made.These configuration changes mostly need to be made by the user.  setup-local-dcom will assist you in making required changes to the Windows Registry.  See the reference blogs for details. The validate-dcom Command validate-dcom is a crucial command.  It should be run before any other commands.  If it does not run successfully then there is no point in running other commands.The validate-dcom command must be used from a DAS machine to test a different Windows machine.  If  validate-dcom runs successfully you can be confident that all the DCOM commands will work.  Conversely, the opposite is also true:  If validate-dcom fails, then no DCOM commands will work. What validate-dcom does Verify that the remote host is not the local machine. Resolves the remote host name Checks that the remote DCOM port is being listened on (135, 139) Checks that the remote host’s File Sharing is enabled (port 445) It copies a file (a script) to the remote host to verify that SAMBA is working and authorization is correct It runs a script that it copied on-the-fly to the remote host. Tips and Tricks The bread and butter commands that use DCOM are existing commands like create-instance, start-instance etc.   All of the commands that have dcom in their name are for dealing with the actual nodes. The way the software works is to call asadmin.bat on the remote machine and run a command.  This means that you can track these commands easily on the remote machine with the usual tools.  E.g. using AS_LOGFILE, looking at log files, etc.  It’s easy to attach a debugger to the remote asadmin process, “just in time”, if necessary. How to debug the remote commands:Edit the asadmin.bat file that is in the glassfish/bin folder.  Use glassfish/lib/nadmin.bat in GlassFish 4.0+Add these options to the java call:-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=1234  Now if you run, say start-instance on DAS, you can attach your debugger, at your leisure, to the remote machines port 1234.  It will be running start-local-instance and patiently waiting for you to attach.

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  • Is finding graph minors without single node pinch points possible?

    - by Alturis
    Is it possible to robustly find all the graph minors within an arbitrary node graph where the pinch points are generally not single nodes? I have read some other posts on here about how to break up your graph into a Hamiltonian cycle and then from that find the graph minors but it seems to be such an algorithm would require that each "room" had "doorways" consisting of single nodes. To explain a bit more a visual aid is necessary. Lets say the nodes below are an example of the typical node graph. What I am looking for is a way to automatically find the different colored regions of the graph (or graph minors)

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  • Running a Mongo Replica Set on Azure VM Roles

    - by Elton Stoneman
    Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/10/15/running-a-mongo-replica-set-on-azure-vm-roles.aspxSetting up a MongoDB Replica Set with a bunch of Azure VMs is straightforward stuff. Here’s a step-by-step which gets you from 0 to fully-redundant 3-node document database in about 30 minutes (most of which will be spent waiting for VMs to fire up). First, create yourself 3 VM roles, which is the minimum number of nodes you need for high availability. You can use any OS that Mongo supports. This guide uses Windows but the only difference will be the mechanism for starting the Mongo service when the VM starts (Windows Service, daemon etc.) While the VMs are provisioning, download and install Mongo locally, so you can set up the replica set with the Mongo shell. We’ll create our replica set from scratch, doing one machine at a time (if you have a single node you want to upgrade to a replica set, it’s the same from step 3 onwards): 1. Setup Mongo Log into the first node, download mongo and unzip it to C:. Rename the folder to remove the version – so you have c:\MongoDB\bin etc. – and create a new folder for the logs, c:\MongoDB\logs. 2. Setup your data disk When you initialize a node in a replica set, Mongo pre-allocates a whole chunk of storage to use for data replication. It will use up to 5% of your data disk, so if you use a Windows VM image with a defsault 120Gb disk and host your data on C:, then Mongo will allocate 6Gb for replication. And that takes a while. Instead you can create yourself a new partition by shrinking down the C: drive in Computer Management, by say 10Gb, and then creating a new logical disk for your data from that spare 10Gb, which will be allocated as E:. Create a new folder, e:\data. 3. Start Mongo When that’s done, start a command line, point to the mongo binaries folder, install Mongo as a Windows Service, running in replica set mode, and start the service: cd c:\mongodb\bin mongod -logpath c:\mongodb\logs\mongod.log -dbpath e:\data -replSet TheReplicaSet –install net start mongodb 4. Open the ports Mongo uses port 27017 by default, so you need to allow access in the machine and in Azure. In the VM, open Windows Firewall and create a new inbound rule to allow access via port 27017. Then in the Azure Management Console for the VM role, under the Configure tab add a new rule, again to allow port 27017. 5. Initialise the replica set Start up your local mongo shell, connecting to your Azure VM, and initiate the replica set: c:\mongodb\bin\mongo sc-xyz-db1.cloudapp.net rs.initiate() This is the bit where the new node (at this point the only node) allocates its replication files, so if your data disk is large, this can take a long time (if you’re using the default C: drive with 120Gb, it may take so long that rs.initiate() never responds. If you’re sat waiting more than 20 minutes, start another instance of the mongo shell pointing to the same machine to check on it). Run rs.conf() and you should see one node configured. 6. Fix the host name for the primary – *don’t miss this one* For the first node in the replica set, Mongo on Windows doesn’t populate the full machine name. Run rs.conf() and the name of the primary is sc-xyz-db1, which isn’t accessible to the outside world. The replica set configuration needs the full DNS name of every node, so you need to manually rename it in your shell, which you can do like this: cfg = rs.conf() cfg.members[0].host = ‘sc-xyz-db1.cloudapp.net:27017’ rs.reconfig(cfg) When that returns, rs.conf() will have your full DNS name for the primary, and the other nodes will be able to connect. At this point you have a working database, so you can start adding documents, but there’s no replication yet. 7. Add more nodes For the next two VMs, follow steps 1 through to 4, which will give you a working Mongo database on each node, which you can add to the replica set from the shell with rs.add(), using the full DNS name of the new node and the port you’re using: rs.add(‘sc-xyz-db2.cloudapp.net:27017’) Run rs.status() and you’ll see your new node in STARTUP2 state, which means its initializing and replicating from the PRIMARY. Repeat for your third node: rs.add(‘sc-xyz-db3.cloudapp.net:27017’) When all nodes are finished initializing, you will have a PRIMARY and two SECONDARY nodes showing in rs.status(). Now you have high availability, so you can happily stop db1, and one of the other nodes will become the PRIMARY with no loss of data or service. Note – the process for AWS EC2 is exactly the same, but with one important difference. On the Azure Windows Server 2012 base image, the MongoDB release for 64-bit 2008R2+ works fine, but on the base 2012 AMI that release keeps failing with a UAC permission error. The standard 64-bit release is fine, but it lacks some optimizations that are in the 2008R2+ version.

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  • Finding an A* heuristic for a directed graph

    - by Janis Peisenieks
    In a previous question, I asked about finding a route (or path if you will) in a city. That is all dandy. The solution I chose was with the A* algorithm, which really seems to suit my needs. What I find puzzling is heuristic. How do I find one in an environment without constant distance between 2 nodes? Meaning, not every 2 nodes have the same distance between them. What I have is nodes (junctures), streets with weight (which may also be one-way), a start/finish node (since the start and end is always in the same place) and a goal node. In an ordinary case, I would just use the same way I got to goal to go back, but since one of the streets could have been a one-way, that may not be possible. The main question How do I find a heuristic in a directed graph?

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  • After deploying services I get incorrect public adress

    - by user84471
    I deployed wordpress and when I type juju status I recievie this: public-adress: node-001185e6777fe When I found what is IP adress of this computer I tried type in webbrowser but I get 502 bad gateway. After juju status: hsf@ubuntu:~$ juju status 2012-10-05 11:26:49,385 INFO Connecting to environment... Enter passphrase for key '/home/hsf/.ssh/id_rsa': 2012-10-05 11:26:51,905 INFO Connected to environment. machines: 0: agent-state: running dns-name: node-00127968a7be.local instance-id: /MAAS/api/1.0/nodes/node-ab7c5eb6-0e08-11e2-bb37-001185e67955/ instance-state: unknown 1: agent-state: running dns-name: node-001185e677fe instance-id: /MAAS/api/1.0/nodes/node-82beae92-0e09-11e2-a134-001185e67955/ instance-state: unknown 2: agent-state: running dns-name: node-001185e6772b.local instance-id: /MAAS/api/1.0/nodes/node-5c21dc18-0e0a-11e2-a134-001185e67955/ instance-state: unknown services: wordpress: charm: cs:precise/wordpress-9 exposed: true relations: loadbalancer: - wordpress units: wordpress/2: agent-state: started machine: 1 open-ports: [] public-address: node-001185e677fe.localdomain 2012-10-05 11:26:52,459 INFO 'status' command finished successfully hsf@ubuntu:~$

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  • How to detect and collide two elastic line segments?

    - by Tautrimas
    There are 4 moving physical nodes in 3D space. They are paired with two elastic line segments / strings (1 <- 2; 3 <- 4). Part I: How to detect the collision of two segments? Part II: On the moment of collision, fifth node is created at the intersection point and here you have the force-based graph. 5-th node (bend point) can slide among the strings as in a real world. Given the new coordinates of 4 nodes, how to calculate the position of the 5-th node on the next frame? I assume string force on the nodes to be F = -k * x where x is the string length. All I came up to is that the force between 5 and 1 equals 5 and 2 (the same with 3 and 4). What are the other properties?.

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  • Nodes inside Cisco VPN. Incoming SSH requests allowed. But can't initiate an outbound SSH.

    - by Douglas Peter
    I've a gateway-to-gateway VPN setup between my Linksys RV042 router and a Cisco VPN. I am able to SSH into any of the machine inside the VPN from my network. But none of the machines inside the VPN can initiate an SSH into my network. It seems they've blocked even all ping requests to my network gateway. This is the requirement: I have scripts that SSH into the machines inside the VPN and run a long mysql query. The query generates an output to a file. The time that these queries take is variable. So I have a loop in my machine that periodically SSHes into the VPN machine and checks if the query has finished, and pulls the generated file using SCP. I need to simplify it thus: The script will run at the machine inside the VPN, and when the query completes, it will SSH into my machine and pushes the generated file. Thanks for any ideas.

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  • Is my implementation of A* wrong?

    - by Bloodyaugust
    I've implemented the A* algorithm in my program. However, it would seem to be functioning incorrectly at times. Below is a screenshot of one such time. The obviously shorter line is to go immediately right at the second to last row. Instead, they move down, around the tower, and continue to their destination (bottom right from top left). Below is my actual code implementation: nodeMap.prototype.findPath = function(p1, p2) { var openList = []; var closedList = []; var nodes = this.nodes; for (var i = 0; i < nodes.length; i++) { //reset heuristics and parents for nodes var curNode = nodes[i]; curNode.f = 0; curNode.g = 0; curNode.h = 0; curNode.parent = null; if (curNode.pathable === false) { closedList.push(curNode); } } openList.push(this.getNode(p1)); while(openList.length > 0) { // Grab the lowest f(x) to process next var lowInd = 0; for(i=0; i<openList.length; i++) { if(openList[i].f < openList[lowInd].f) { lowInd = i; } } var currentNode = openList[lowInd]; if (currentNode === this.getNode(p2)) { var curr = currentNode; var ret = []; while(curr.parent) { ret.push(curr); curr = curr.parent; } return ret.reverse(); } closedList.push(currentNode); for (i = 0; i < openList.length; i++) { //remove currentNode from openList if (openList[i] === currentNode) { openList.splice(i, 1); break; } } for (i = 0; i < currentNode.neighbors.length; i++) { if(closedList.indexOf(currentNode.neighbors[i]) !== -1 ) { continue; } if (currentNode.neighbors[i].isPathable === false) { closedList.push(currentNode.neighbors[i]); continue; } var gScore = currentNode.g + 1; // 1 is the distance from a node to it's neighbor var gScoreIsBest = false; if (openList.indexOf(currentNode.neighbors[i]) === -1) { //save g, h, and f then save the current parent gScoreIsBest = true; currentNode.neighbors[i].h = currentNode.neighbors[i].heuristic(this.getNode(p2)); openList.push(currentNode.neighbors[i]); } else if (gScore < currentNode.neighbors[i].g) { //current g better than previous g gScoreIsBest = true; } if (gScoreIsBest) { currentNode.neighbors[i].parent = currentNode; currentNode.neighbors[i].g = gScore; currentNode.neighbors[i].f = currentNode.neighbors[i].g + currentNode.neighbors[i].h; } } } return false; } Towers block pathability. Is there perhaps something I am missing here, or does A* not always find the shortest path in a situation such as this? Thanks in advance for any help.

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  • A* algorithm very slow

    - by Amaranth
    I have an programming a RTS game (I use XNA with C#). The pathfinding is working fine, except that when it has a lot of node to search in, there is a lag period of one or two seconds, it happens mainly when there is no path to the target destination, since it that situation there is more nodes to explore. I have the same problem when the path is shorter but selected more than 3 units (can't take the same path since the selected units can be in different part of the map). private List<NodeInfo> FindPath(Unit u, NodeInfo start, NodeInfo end) { Map map = GameInfo.GetInstance().GameMap; _nearestToTarget = start; start.MoveCost = 0; Vector2 endPosition = map.getTileByPos(end.X, end.Y).Position; //getTileByPos simply gets the tile in a 2D array with the X and Y indexes start.EstimatedRemainingCost = (int)(endPosition - map.getTileByPos(start.X, start.Y).Position).Length(); start.Parent = null; List<NodeInfo> openedNodes = new List<NodeInfo>(); ; List<NodeInfo> closedNodes = new List<NodeInfo>(); Point[] movements = GetMovements(u.UnitType); openedNodes.Add(start); while (!closedNodes.Contains(end) && openedNodes.Count > 0) { //Loop in nodes to find lowest cost NodeInfo currentNode = FindLowestCostOpenedNode(openedNodes); openedNodes.Remove(currentNode); closedNodes.Add(currentNode); Vector2 previousMouvement; if (currentNode.Parent == null) { previousMouvement = ConvertRotationToDirectionVector(u.Rotation); } else { previousMouvement = map.getTileByPos(currentNode.X, currentNode.Y).Position - map.getTileByPos(currentNode.Parent.X, currentNode.Parent.Y).Position; previousMouvement.Normalize(); } //For each neighbor foreach (Point movement in movements) { Point exploredGridPos = new Point(currentNode.X + movement.X, currentNode.Y + movement.Y); //Checks if valid move and checks if not if closed nodes list if (ValidNavigableNode(u.UnitType, new Point(currentNode.X, currentNode.Y), exploredGridPos) && !closedNodes.Contains(_gridMap[exploredGridPos.Y, exploredGridPos.X])) { NodeInfo exploredNode = _gridMap[exploredGridPos.Y, exploredGridPos.X]; Tile.TileType exploredTerrain = map.getTileByPos(exploredGridPos.X, exploredGridPos.Y).TerrainType; if(openedNodes.Contains(exploredNode)) { int newCost = currentNode.MoveCost + GetMoveCost(previousMouvement, movement, exploredTerrain); if (newCost < exploredNode.MoveCost) { exploredNode.Parent = currentNode; exploredNode.MoveCost = newCost; //Find nearest tile to the target (in case doesn't find path to target) //Only compares the node to the current nearest FindNearest(exploredNode); } } else { exploredNode.Parent = currentNode; exploredNode.MoveCost = currentNode.MoveCost + GetMoveCost(previousMouvement, movement, exploredTerrain); Vector2 exploredNodeWorldPos = map.getTileByPos(exploredGridPos.X, exploredGridPos.Y).Position; exploredNode.EstimatedRemainingCost = (int)(endPosition - exploredNodeWorldPos).Length(); //Find nearest tile to the target (in case doesn't find path to target) //Only compares the node to the current nearest FindNearest(exploredNode); openedNodes.Add(exploredNode); } } } } return closedNodes; } After that, I simply check if the end node is contained in the returned nodes. If so, I add the end node and each parent until I reach the start. If not, I add the nearestToTarget and each parent until I reach the start. I added a condition before calling FindPath so that only one unit can call a find path each frame (60 frame per second), but it makes no difference. I thought maybe I could solve this by allowing the find path to run in background while the game continues to run correctly, even if it takes a few frame (it is currently sequential sonce it is called in the update() of the unit if there's a target location but no path), but I don't really know how... I also though about sorting my opened nodes list by cost so I don't have to loop them, but I don't know if that would have an effect on the performance... Would there be other solutions? P.S. In the code, when I get the Move Cost, I check if the unit has to turn to perform the move, and the terrain type, nothing hard to do.

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  • how can I code a recursive query in an Entity Framework model?

    - by Greg
    Hi, I have a model which includes NODES, and RELATIONSHIPS (that tie the nodes together, via a parent_node, child_node arrangement). Q1 - Is there any way in EF / Linq-to-entities to perform a query on nodes (e.g. context.Nodes..) to find say "all parents" or "or children" in the graph? Q2 - If there's not in Linq-to-entities, is there any other way to do this other than writing a method that manually goes through and doing it? Q3 - If manual is the only way to do it, should I be concerned about the number of database hits that will be going out to the database as the method keeps recursing through the data? Or more specifically, is there any EF caching type feature that might assist here in ensuring the method is performance from a "number of database hits" point of view? thanks thanks

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  • Pseudo LRU tree algorithm.

    - by patros
    A lot of descriptions of Pseudo LRU algorithms involve using a binary search tree, and setting flags to "point away" from the node you're searching for every time you access the tree. This leads to a reasonable approximation of LRU. However, it seems from the descriptions that all of the nodes deemed LRU would be leaf nodes. Is there a pseudo-LRU algorithm that deals with a static tree that will still perform reasonably well, while determining that non-leaf nodes are suitable LRU candidates?

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  • How to compile jsoup through Ant?

    - by JackWM
    I tried to use Ant to compile the jsoup source. I can compile successfully, but cannot pass the test. Here is the process: jsoup version: 1.6.3 ; Ant version: 1.8.2 the source of jsoup is in the directory src/ I made a build file src/build.xml This file contains <project name="jsoup"> <target name="compile"> <mkdir dir="build/classes"/> <javac srcdir="src" destdir="build/classes" includeantruntime="false"/> </target> <target name="jar"> <mkdir dir="build/jar"/> <jar destfile="build/jar/jsoup.jar" basedir="build/classes"> <manifest> <attribute name="Main-Class" value="StateTrace"/> </manifest> </jar> </target> <target name="run"> <!--<java jar="build/jar/jsoup.jar" input="htmls/index.html" fork="true"/>--> <exec executable="java"> <arg value="-jar"/> <arg value="build/jar/jsoup.jar"/> <arg value="htmls/index.html"/> </exec> </target> </project> Note: 1. StateTrace.java is my own test program; 2. htmls/index.html is the input to StateTrace.java. Then I compile and run it with Ant: > ant compile > ant jar > ant run After this, I got err like: run: [exec] Exception in thread "main" java.lang.ExceptionInInitializerError [exec] at org.jsoup.nodes.Entities$EscapeMode.<clinit>(Unknown Source) [exec] at org.jsoup.nodes.Document$OutputSettings.<init>(Unknown Source) [exec] at org.jsoup.nodes.Document.<init>(Unknown Source) [exec] at org.jsoup.parser.TreeBuilder.initialiseParse(Unknown Source) [exec] at org.jsoup.parser.TreeBuilder.parse(Unknown Source) [exec] at org.jsoup.parser.HtmlTreeBuilder.parse(Unknown Source) [exec] at org.jsoup.parser.Parser.parse(Unknown Source) [exec] at org.jsoup.Jsoup.parse(Unknown Source) [exec] at StateTrace.main(Unknown Source) [exec] Caused by: java.lang.NullPointerException [exec] at java.util.Properties$LineReader.readLine(Properties.java:418) [exec] at java.util.Properties.load0(Properties.java:337) [exec] at java.util.Properties.load(Properties.java:325) [exec] at org.jsoup.nodes.Entities.loadEntities(Unknown Source) [exec] at org.jsoup.nodes.Entities.<clinit>(Unknown Source) [exec] ... 9 more [exec] Result: 1 BUILD SUCCESSFUL Total time: 0 seconds However, if I manually compiled all the java source, like javac src/org/jsoup/*.java src/org/jsoup/parser/*.java src/org/jsoup/examples/*.java src/org/jsoup/nodes/*.java src/org/jsoup/safety/*.java src/org/jsoup/select/*.java src/org/jsoup/helper/*.java I could compile successfully and pass my test. Any clue? Thanks!

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  • JavaScript tree / treegrid libraries

    - by desau
    I'm looking for a good JavaScript tree / treegrid package. Now -- before you answer: It needs to be able to perform well with lots of nodes. Perhaps 1,000 sibling nodes. It needs to be able to draw to a usable state within 2 or 3 seconds with 1,000 nodes. It doesn't necessarily need to draw all 1,000 nodes at once -- if it supports some sort of "smart rendering" or fake scrolling. Beyond that, column resizing, drag and drop, inline editing would all be nice, although I could probably add that functionality myself. I've already tried dojo's tree and yahoo's YUI treeview. Both are too slow.

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  • Psuedo LRU tree algorithm.

    - by patros
    A lot of descriptions of Pseudo LRU algorithms involve using a binary search tree, and setting flags to "point away" from the node you're searching for every time you access the tree. This leads to a reasonable approximation of LRU. However, it seems from the descriptions that all of the nodes deemed LRU would be leaf nodes. Is there a pseudo-LRU algorithm that deals with a static tree that will still perform reasonably well, while determining that non-leaf nodes are suitable LRU candidates?

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  • Graph layouting with Perl

    - by jonny
    Ok, I have a flowchart definition (basically, array of nodes and edges for each node). Now I want to calculate coordinates for every task in the flow, preferably hierarchycal style. I need something like Graph::Easy::Layout but I have no idea how to get nodes coordinates: I render nodes myself and I only want to retrieve box coordinates/size. Any suggestions? What I need is a cpan module avialable even in Debian repository.

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  • Conditional Drag and Drop Operations in Flex/AS3 Tree

    - by user163757
    Good day everyone. I am currently working with a hierarchical tree structure in AS3/Flex, and want to enable drag and drop capabilities under certain conditions: Only parent/top level nodes can be moved Parent/top level nodes must remain at this level; they can not be moved to child nodes of other parent nodes Using the dragEnter event of the tree, I am able to handle condition 1 easily. private function onDragEnter(event:DragEvent):void { // only parent nodes (map layers) are moveable event.preventDefault(); if(toc.selectedItem.hasOwnProperty("layer")) DragManager.acceptDragDrop(event.target as UIComponent); else DragManager.showFeedback(DragManager.NONE); } Handling the second condition is proving to be a bit more difficult. I am pretty sure the dragOver event is the place for logic. I have been experimenting with calculateDropIndex, but that always gives me the index of the parent node, which doesn't help check if the potential drop location is acceptable or not. Below is some pseudo code of what I am looking to accomplish. private function onDragOver(e:DragEvent):void { // if potential drop location has parents // dont allow drop // else // allow drop } Can anyone provide advice how to implement this?

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  • Lazy Loading in dynatree

    - by gnomixa
    In this component http://wwwendt.de/tech/dynatree/index.html under 5.4 Loading child nodes on demand ('lazy loading') it seems that the only way to load the tree nodes in a lazy manner is to grab them from web service. What if I want to grab the nodes from a data structure? Any advice?

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  • TreeView Children

    - by Arpit
    I have TreeView as below . Account Payable Address Customer Account Receivable Address Area If I will select Parent nodes then how I can display in ListView of particular child nodes? Also when I click on root node then how I can display only all parent nodes in ListView? Thanks .

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