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• What is bondib1 used for on SPARC SuperCluster with InfiniBand, Solaris 11 networking & Oracle RAC?

  - by user12620111

  A co-worker asked the following question about a SPARC SuperCluster InfiniBand network: > on the database nodes the RAC nodes communicate over the cluster_interconnect. This is the > 192.168.10.0 network on bondib0. (according to ./crs/install/crsconfig_params NETWORKS> setting) > What is bondib1 used for? Is it a HA counterpart in case bondib0 dies? This is my response: Summary: bondib1 is currently only being used for outbound cluster interconnect interconnect traffic. Details: bondib0 is the cluster_interconnect $ oifcfg getif            bondeth0  10.129.184.0  global  public bondib0  192.168.10.0  global  cluster_interconnect ipmpapp0  192.168.30.0  global  public bondib0 and bondib1 are on 192.168.10.1 and 192.168.10.2 respectively. # ipadm show-addr | grep bondi bondib0/v4static  static   ok           192.168.10.1/24 bondib1/v4static  static   ok           192.168.10.2/24 Hostnames tied to the IPs are node1-priv1 and node1-priv2  # grep 192.168.10 /etc/hosts 192.168.10.1    node1-priv1.us.oracle.com   node1-priv1 192.168.10.2    node1-priv2.us.oracle.com   node1-priv2 For the 4 node RAC interconnect: Each node has 2 private IP address on the 192.168.10.0 network. Each IP address has an active InfiniBand link and a failover InfiniBand link. Thus, the 4 node RAC interconnect is using a total of 8 IP addresses and 16 InfiniBand links. bondib1 isn't being used for the Virtual IP (VIP): $ srvctl config vip -n node1 VIP exists: /node1-ib-vip/192.168.30.25/192.168.30.0/255.255.255.0/ipmpapp0, hosting node node1 VIP exists: /node1-vip/10.55.184.15/10.55.184.0/255.255.255.0/bondeth0, hosting node node1 bondib1 is on bondib1_0 and fails over to bondib1_1: # ipmpstat -g GROUP       GROUPNAME   STATE     FDT       INTERFACES ipmpapp0    ipmpapp0    ok        --        ipmpapp_0 (ipmpapp_1) bondeth0    bondeth0    degraded  --        net2 [net5] bondib1     bondib1     ok        --        bondib1_0 (bondib1_1) bondib0     bondib0     ok        --        bondib0_0 (bondib0_1) bondib1_0 goes over net24 # dladm show-link | grep bond LINK                CLASS     MTU    STATE    OVER bondib0_0           part      65520  up       net21 bondib0_1           part      65520  up       net22 bondib1_0           part      65520  up       net24 bondib1_1           part      65520  up       net23 net24 is IB Partition FFFF # dladm show-ib LINK         HCAGUID         PORTGUID        PORT STATE  PKEYS net24        21280001A1868A  21280001A1868C  2    up     FFFF net22        21280001CEBBDE  21280001CEBBE0  2    up     FFFF,8503 net23        21280001A1868A  21280001A1868B  1    up     FFFF,8503 net21        21280001CEBBDE  21280001CEBBDF  1    up     FFFF On Express Module 9 port 2: # dladm show-phys -L LINK              DEVICE       LOC net21             ibp4         PCI-EM1/PORT1 net22             ibp5         PCI-EM1/PORT2 net23             ibp6         PCI-EM9/PORT1 net24             ibp7         PCI-EM9/PORT2 Outbound traffic on the 192.168.10.0 network will be multiplexed between bondib0 & bondib1 # netstat -rn Routing Table: IPv4   Destination           Gateway           Flags  Ref     Use     Interface -------------------- -------------------- ----- ----- ---------- --------- 192.168.10.0         192.168.10.2         U        16    6551834 bondib1   192.168.10.0         192.168.10.1         U         9    5708924 bondib0   There is a lot more traffic on bondib0 than bondib1 # /bin/time snoop -I bondib0 -c 100 > /dev/null Using device ipnet/bondib0 (promiscuous mode) 100 packets captured real        4.3 user        0.0 sys         0.0 (100 packets in 4.3 seconds = 23.3 pkts/sec) # /bin/time snoop -I bondib1 -c 100 > /dev/null Using device ipnet/bondib1 (promiscuous mode) 100 packets captured real       13.3 user        0.0 sys         0.0 (100 packets in 13.3 seconds = 7.5 pkts/sec) Half of the packets on bondib0 are outbound (from self). The remaining packet are split evenly, from the other nodes in the cluster. # snoop -I bondib0 -c 100 | awk '{print $1}' | sort | uniq -c Using device ipnet/bondib0 (promiscuous mode) 100 packets captured   49 node1-priv1.us.oracle.com   24 node2-priv1.us.oracle.com   14 node3-priv1.us.oracle.com   13 node4-priv1.us.oracle.com 100% of the packets on bondib1 are outbound (from self), but the headers in the packets indicate that they are from the IP address associated with bondib0: # snoop -I bondib1 -c 100 | awk '{print $1}' | sort | uniq -c Using device ipnet/bondib1 (promiscuous mode) 100 packets captured  100 node1-priv1.us.oracle.com The destination of the bondib1 outbound packets are split evenly, to node3 and node 4. # snoop -I bondib1 -c 100 | awk '{print $3}' | sort | uniq -c Using device ipnet/bondib1 (promiscuous mode) 100 packets captured   51 node3-priv1.us.oracle.com   49 node4-priv1.us.oracle.com Conclusion: bondib1 is currently only being used for outbound cluster interconnect interconnect traffic.

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• dynatree: how can i select child node programmatically

  - by Muhammad Adeel Zahid

  hello everyone i m using jquery's dynaTree in my application and i want to select the all the child nodes programmably when a node is selected. the structure of my tree is as follows <div id = "tree"> <ul> <li>package 1 <ul> <li>module 1.1 <ul> <li> document 1.1.1</li> <li> document 1.1.2</li> </ul> </li> <li>module 1.2 <ul> <li>document 1.2.1</li> <li>document 1.2.2</li> </ul> </li> </ul> </li> <li> package 2 <ul> <li> module 2.1 <ul> <li>document 2.1.1</li> <li>document 2.1.1</li> </ul> </li> </ul> </li> </ul> </div> now what i want is that when i click on tree node with title "package 1" all its child nodes i.e (module 1.1, document 1.1.1, document 1.1.2, module 1.2, document 1.2.1, document 1.2.2) should also be selected below is the approach i tried to use $("#tree").dynatree({ onSelect: function(flag, dtnode) { // This will happen each time a check box is selected/deselected var selectedNodes = dtnode.tree.getSelectedNodes(); var selectedKeys = $.map(selectedNodes, function(node) { //alert(node.data.key); return node.data.key; }); // Set the hidden input field's value to the selected items $('#SelectedItems').val(selectedKeys.join(",")); if (flag) { child = dtnode.childList; alert(child.length); for (i = 0; i < child.length; i++) { var x = child[i].select(true); alert(i); } } }, checkbox: true, onActivate: function(dtnode) { //alert("You activated " + dtnode.data.key); } }); in the if(flag) condition i get all the child nodes of element that is selected by user and it gives me the correct value that i can see from alert(child.length) statement. then i run the loop to select all the children but loop never goes beyond the statement var x = child[i].select(true); and i can never see the statement alert(i) being executed. the result of above statement is that if i select package 1, module 1.1 and document 1.1.1 is also selected but never does it execute alert(i) statement neither other children of package 1 are selected. in my view when first time child[i].select(true) statement is executed it also triggers the on select event of its children thus making a recursion kind of thing is my thinking correct? no matter recursion or what why on earth does it not complete the loop and execute very next instruction alert(i). please help me in solving this problem. i m dying to see that alert any suggestion and help is highly appriciated thanks Adeel

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• Converting hierarchial data into an unordered list Programmatically using asp.net/C#

  - by kranthi

  hi everyone, I've data which looks something like this. | id | name | depth | itemId | +-----+----------------------+-------+-------+ | 0 | ELECTRONICS | 0 | NULL | | 1 | TELEVISIONS | 1 | NULL | | 400 | Tube | 2 | NULL | | 432 | LCD | 3 | 1653 | | 422 | Plasma | 3 | 1633 | | 416 | Portable electronics | 3 | 1595 | | 401 | MP3 Player | 3 | 1249 | | 191 | Flash | 2 | NULL | | 555 | CD Players | 3 | 2198 | | 407 | 2 Way Radio | 3 | 1284 | | 388 | I've a problem with | 3 | 1181 | | 302 | What is your bill pa | 3 | 543 | | 203 | Where can I find my | 3 | 299 | | 201 | I would like to make | 3 | 288 | | 200 | Do you have any job | 3 | 284 | | 192 | About Us | 3 | NULL | | 199 | What can you tell me | 4 | 280 | | 198 | Do you help pr | 4 | 276 | | 197 | would someone help co| 4 | 272 | | 196 | can you help ch | 4 | 268 | | 195 | What awards has Veri | 4 | 264 | | 194 | What's the latest ne | 4 | 260 | | 193 | Can you tell me more | 4 | 256 | | 180 | Site Help | 2 | NULL | | 421 | Where are the | 3 | 1629 | | 311 | How can I access My | 3 | 557 | | 280 | Why isn't the page a | 3 | 512 | To convert the above data into unordered list based on depth, I'm using the following code int lastDepth = -1; int numUL = 0; StringBuilder output = new StringBuilder(); foreach (DataRow row in ds.Tables[0].Rows) { int currentDepth = Convert.ToInt32(row["Depth"]); if (lastDepth < currentDepth) { if (currentDepth == 0) { output.Append("<ul class=\"simpleTree\">"); output.AppendFormat("<li class=\"root\"><span><a href=\"#\" title=\"root\">root</a></span><ul><li class=\"open\" ><span><a href=\"#\" title={1}>{0}</a></span>", row["name"],row["id"]); } else { output.Append("<ul>"); if(currentDepth==1) output.AppendFormat("<li><span>{0}</span>", row["name"]); else output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"], row["id"]); } numUL++; } else if (lastDepth > currentDepth) { output.Append("</li></ul></li>"); if(currentDepth==1) output.AppendFormat("<li><span>{0}</span>", row["name"]); else output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"], row["id"]); numUL--; } else if (lastDepth > -1) { output.Append("</li>"); output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"],row["id"]); } lastDepth = currentDepth; } for (int i = 1; i <= numUL+1; i++) { output.Append("</li></ul>"); } myliteral.text=output.ToString(); But the resulting unordered list doesnt seem to be forming properly(using which i am constructing a tree).For example "Site Help" with id '180' is supposed to appear as a direct child of "Televisions" with id '1',is appearing as a direct child of 'Flash' with id '191' using my code.so in addition to considering depth,I've decided to consider itemid as well in order to get the treeview properly.Those rows of the table with itemId not equal to null are not supposed to have a child node(i.e.,they are the leaf nodes in the tree) and all the other nodes can have child nodes. Please could someone help me in constructing a proper unordered list based on my depth,itemid coulumns? Thanks.

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• Python: Improving long cumulative sum

  - by Bo102010

  I have a program that operates on a large set of experimental data. The data is stored as a list of objects that are instances of a class with the following attributes: time_point - the time of the sample cluster - the name of the cluster of nodes from which the sample was taken code - the name of the node from which the sample was taken qty1 = the value of the sample for the first quantity qty2 = the value of the sample for the second quantity I need to derive some values from the data set, grouped in three ways - once for the sample as a whole, once for each cluster of nodes, and once for each node. The values I need to derive depend on the (time sorted) cumulative sums of qty1 and qty2: the maximum value of the element-wise sum of the cumulative sums of qty1 and qty2, the time point at which that maximum value occurred, and the values of qty1 and qty2 at that time point. I came up with the following solution: dataset.sort(key=operator.attrgetter('time_point')) # For the whole set sys_qty1 = 0 sys_qty2 = 0 sys_combo = 0 sys_max = 0 # For the cluster grouping cluster_qty1 = defaultdict(int) cluster_qty2 = defaultdict(int) cluster_combo = defaultdict(int) cluster_max = defaultdict(int) cluster_peak = defaultdict(int) # For the node grouping node_qty1 = defaultdict(int) node_qty2 = defaultdict(int) node_combo = defaultdict(int) node_max = defaultdict(int) node_peak = defaultdict(int) for t in dataset: # For the whole system ###################################################### sys_qty1 += t.qty1 sys_qty2 += t.qty2 sys_combo = sys_qty1 + sys_qty2 if sys_combo > sys_max: sys_max = sys_combo # The Peak class is to record the time point and the cumulative quantities system_peak = Peak(time_point=t.time_point, qty1=sys_qty1, qty2=sys_qty2) # For the cluster grouping ################################################## cluster_qty1[t.cluster] += t.qty1 cluster_qty2[t.cluster] += t.qty2 cluster_combo[t.cluster] = cluster_qty1[t.cluster] + cluster_qty2[t.cluster] if cluster_combo[t.cluster] > cluster_max[t.cluster]: cluster_max[t.cluster] = cluster_combo[t.cluster] cluster_peak[t.cluster] = Peak(time_point=t.time_point, qty1=cluster_qty1[t.cluster], qty2=cluster_qty2[t.cluster]) # For the node grouping ##################################################### node_qty1[t.node] += t.qty1 node_qty2[t.node] += t.qty2 node_combo[t.node] = node_qty1[t.node] + node_qty2[t.node] if node_combo[t.node] > node_max[t.node]: node_max[t.node] = node_combo[t.node] node_peak[t.node] = Peak(time_point=t.time_point, qty1=node_qty1[t.node], qty2=node_qty2[t.node]) This produces the correct output, but I'm wondering if it can be made more readable/Pythonic, and/or faster/more scalable. The above is attractive in that it only loops through the (large) dataset once, but unattractive in that I've essentially copied/pasted three copies of the same algorithm. To avoid the copy/paste issues of the above, I tried this also: def find_peaks(level, dataset): def grouping(object, attr_name): if attr_name == 'system': return attr_name else: return object.__dict__[attrname] cuml_qty1 = defaultdict(int) cuml_qty2 = defaultdict(int) cuml_combo = defaultdict(int) level_max = defaultdict(int) level_peak = defaultdict(int) for t in dataset: cuml_qty1[grouping(t, level)] += t.qty1 cuml_qty2[grouping(t, level)] += t.qty2 cuml_combo[grouping(t, level)] = (cuml_qty1[grouping(t, level)] + cuml_qty2[grouping(t, level)]) if cuml_combo[grouping(t, level)] > level_max[grouping(t, level)]: level_max[grouping(t, level)] = cuml_combo[grouping(t, level)] level_peak[grouping(t, level)] = Peak(time_point=t.time_point, qty1=node_qty1[grouping(t, level)], qty2=node_qty2[grouping(t, level)]) return level_peak system_peak = find_peaks('system', dataset) cluster_peak = find_peaks('cluster', dataset) node_peak = find_peaks('node', dataset) For the (non-grouped) system-level calculations, I also came up with this, which is pretty: dataset.sort(key=operator.attrgetter('time_point')) def cuml_sum(seq): rseq = [] t = 0 for i in seq: t += i rseq.append(t) return rseq time_get = operator.attrgetter('time_point') q1_get = operator.attrgetter('qty1') q2_get = operator.attrgetter('qty2') timeline = [time_get(t) for t in dataset] cuml_qty1 = cuml_sum([q1_get(t) for t in dataset]) cuml_qty2 = cuml_sum([q2_get(t) for t in dataset]) cuml_combo = [q1 + q2 for q1, q2 in zip(cuml_qty1, cuml_qty2)] combo_max = max(cuml_combo) time_max = timeline.index(combo_max) q1_at_max = cuml_qty1.index(time_max) q2_at_max = cuml_qty2.index(time_max) However, despite this version's cool use of list comprehensions and zip(), it loops through the dataset three times just for the system-level calculations, and I can't think of a good way to do the cluster-level and node-level calaculations without doing something slow like: timeline = defaultdict(int) cuml_qty1 = defaultdict(int) #...etc. for c in cluster_list: timeline[c] = [time_get(t) for t in dataset if t.cluster == c] cuml_qty1[c] = [q1_get(t) for t in dataset if t.cluster == c] #...etc. Does anyone here at Stack Overflow have suggestions for improvements? The first snippet above runs well for my initial dataset (on the order of a million records), but later datasets will have more records and clusters/nodes, so scalability is a concern. This is my first non-trivial use of Python, and I want to make sure I'm taking proper advantage of the language (this is replacing a very convoluted set of SQL queries, and earlier versions of the Python version were essentially very ineffecient straight transalations of what that did). I don't normally do much programming, so I may be missing something elementary. Many thanks!

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• Preventing multiple repeat selection of synchronized Controls ?

  - by BillW

  The working code sample here synchronizes (single) selection in a TreeView, ListView, and ComboBox via the use of lambda expressions in a dictionary where the Key in the dictionary is a Control, and the Value of each Key is an Action<int. Where I am stuck is that I am getting multiple repetitions of execution of the code that sets the selection in the various controls in a way that's unexpected : it's not recursing : there's no StackOverFlow error happening; but, I would like to figure out why the current strategy for preventing multiple selection of the same controls is not working. Perhaps the real problem here is distinguishing between a selection update triggered by the end-user and a selection update triggered by the code that synchronizes the other controls ? Note: I've been experimenting with using Delegates, and forms of Delegates like Action<T>, to insert executable code in Dictionaries : I "learn best" by posing programming "challenges" to myself, and implementing them, as well as studying, at the same time, the "golden words" of luminaries like Skeet, McDonald, Liberty, Troelsen, Sells, Richter. Note: Appended to this question/code, for "deep background," is a statement of how I used to do things in pre C#3.0 days where it seemed like I did need to use explicit measures to prevent recursion when synchronizing selection. Code : Assume a WinForms standard TreeView, ListView, ComboBox, all with the same identical set of entries (i.e., the TreeView has only root nodes; the ListView, in Details View, has one Column). private Dictionary<Control, Action<int>> ControlToAction = new Dictionary<Control, Action<int>>(); private void Form1_Load(object sender, EventArgs e) { // add the Controls to be synchronized to the Dictionary // with appropriate Action<int> lambda expressions ControlToAction.Add(treeView1, (i => { treeView1.SelectedNode = treeView1.Nodes[i]; })); ControlToAction.Add(listView1, (i => { listView1.Items[i].Selected = true; })); ControlToAction.Add(comboBox1, (i => { comboBox1.SelectedIndex = i; })); } private void synchronizeSelection(int i, Control currentControl) { foreach(Control theControl in ControlToAction.Keys) { // skip the 'current control' if (theControl == currentControl) continue; // for debugging only Console.WriteLine(theControl.Name + " synchronized"); // execute the Action<int> associated with the Control ControlToAction[theControl](i); } } private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { synchronizeSelection(e.Node.Index, treeView1); } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { synchronizeSelection(listView1.SelectedIndices[0], listView1); } } private void comboBox1_SelectedValueChanged(object sender, EventArgs e) { if (comboBox1.SelectedIndex > -1) { synchronizeSelection(comboBox1.SelectedIndex, comboBox1); } } background : pre C# 3.0 Seems like, back in pre C# 3.0 days, I was always using a boolean flag to prevent recursion when multiple controls were updated. For example, I'd typically have code like this for synchronizing a TreeView and ListView : assuming each Item in the ListView was synchronized with a root-level node of the TreeView via a common index : // assume ListView is in 'Details View,' has a single column, // MultiSelect = false // FullRowSelect = true // HideSelection = false; // assume TreeView // HideSelection = false // FullRowSelect = true // form scoped variable private bool dontRecurse = false; private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { if(dontRecurse) return; dontRecurse = true; listView1.Items[e.Node.Index].Selected = true; dontRecurse = false; } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { if(dontRecurse) return // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { dontRecurse = true; treeView1.SelectedNode = treeView1.Nodes[listView1.SelectedIndices[0]]; dontRecurse = false; } } Then it seems, somewhere around FrameWork 3~3.5, I could get rid of the code to suppress recursion, and there was was no recursion (at least not when synchronizing a TreeView and a ListView). By that time it had become a "habit" to use a boolean flag to prevent recursion, and that may have had to do with using a certain third party control.

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• How to parse HTML with TouchXML or some other alternative.

  - by 0SX

  Hi, I'm trying to parse the HTML presented below with TouchXML but it keeps crashing when I try to extract certain attributes. I'm totally new to the parser world so I apologize for being a complete idiot. I need help to parse this HTML. What I'm trying to accomplish is to parse each attribute and value or what not and copy them to a string. I've been trying to find a good parser to parse HTML and I believe TouchXML is the best I've seen because of Tidy. Speaking of Tidy, How could I run this HTML through Tidy first then parse it? I'm not sure how to do this. Here is the code that I have so far that doesn't work due to it's not pulling everything I need from the HTML. Any help or advice would be much appreciated. Thanks My current code: NSMutableArray *res = [[NSMutableArray alloc] init]; // using local resource file NSString *XMLPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"example.html"]; NSData *XMLData = [NSData dataWithContentsOfFile:XMLPath]; CXMLDocument *doc = [[[CXMLDocument alloc] initWithData:XMLData options:0 error:nil] autorelease]; NSArray *nodes = NULL; nodes = [doc nodesForXPath:@"//div" error:nil]; for (CXMLElement *node in nodes) { NSMutableDictionary *item = [[NSMutableDictionary alloc] init]; [item setObject:[[node attributeForName:@"id"] stringValue] forKey:@"id"]; [res addObject:item]; [item release]; } NSLog(@"%@", res); [res release]; HTML file that needs to be parsed: <html> <head> <base target="_blank" /> </head> <body style="margin:2;"> <div id="group"> <div id="groupURL"><a href="http://www.example.com/groups">Group URL</a></div> <img id="grouplogo" src="http://images.example.com/groups/image.png" /> <div id="groupcomputer"><a href="http://www.example.com/groups/page" title="Group Title">Group title this would be here</a></div> <div id="groupinfos"> <div id="groupinfo-l">Person</div><div id="groupinfo-r">Ralph</div> <div id="groupinfo-l">Years</div><div id="groupinfo-r">4 years</div> <div id="groupinfo-l">Salary</div><div id="groupinfo-r">100K</div> <div id="groupinfo-l">Other</div><div id="groupoth" style="width:15px">other info</div> </body> </html> EDIT: I could use Element Parser but I need to know how to extract the Person's Name from the following example which would be Ralph in this case. <div id="groupinfo-l">Person</div><div id="groupinfo-r">Ralph</div>

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• A* (A-star) implementation in AS3

  - by Bryan Hare

  Hey, I am putting together a project for a class that requires me to put AI in a top down Tactical Strategy game in Flash AS3. I decided that I would use a node based path finding approach because the game is based on a circular movement scheme. When a player moves a unit he essentially draws a series of line segments that connect that a player unit will follow along. I am trying to put together a similar operation for the AI units in our game by creating a list of nodes to traverse to a target node. Hence my use of Astar (the resulting path can be used to create this line). Here is my Algorithm function findShortestPath (startN:node, goalN:node) { var openSet:Array = new Array(); var closedSet:Array = new Array(); var pathFound:Boolean = false; startN.g_score = 0; startN.h_score = distFunction(startN,goalN); startN.f_score = startN.h_score; startN.fromNode = null; openSet.push (startN); var i:int = 0 for(i= 0; i< nodeArray.length; i++) { for(var j:int =0; j<nodeArray[0].length; j++) { if(!nodeArray[i][j].isPathable) { closedSet.push(nodeArray[i][j]); } } } while (openSet.length != 0) { var cNode:node = openSet.shift(); if (cNode == goalN) { resolvePath (cNode); return true; } closedSet.push (cNode); for (i= 0; i < cNode.dirArray.length; i++) { var neighborNode:node = cNode.nodeArray[cNode.dirArray[i]]; if (!(closedSet.indexOf(neighborNode) == -1)) { continue; } neighborNode.fromNode = cNode; var tenativeg_score:Number = cNode.gscore + distFunction(neighborNode.fromNode,neighborNode); if (openSet.indexOf(neighborNode) == -1) { neighborNode.g_score = neighborNode.fromNode.g_score + distFunction(neighborNode,cNode); if (cNode.dirArray[i] >= 4) { neighborNode.g_score -= 4; } neighborNode.h_score=distFunction(neighborNode,goalN); neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; insertIntoPQ (neighborNode, openSet); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); } else if (tenativeg_score <= neighborNode.g_score) { neighborNode.fromNode=cNode; neighborNode.g_score=cNode.g_score+distFunction(neighborNode,cNode); if (cNode.dirArray[i]>=4) { neighborNode.g_score-=4; } neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; openSet.splice (openSet.indexOf(neighborNode),1); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); insertIntoPQ (neighborNode, openSet); } } } trace ("fail"); return false; } Right now this function creates paths that are often not optimal or wholly inaccurate given the target and this generally happens when I have nodes that are not path able, and I am not quite sure what I am doing wrong right now. If someone could help me correct this I would appreciate it greatly. Some Notes My OpenSet is essentially a Priority Queue, so thats how I sort my nodes by cost. Here is that function function insertIntoPQ (iNode:node, pq:Array) { var inserted:Boolean=true; var iterater:int=0; while (inserted) { if (iterater==pq.length) { pq.push (iNode); inserted=false; } else if (pq[iterater].f_score >= iNode.f_score) { pq.splice (iterater,0,iNode); inserted=false; } ++iterater; } } Thanks!

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• Astar implementation in AS3

  - by Bryan Hare

  Hey, I am putting together a project for a class that requires me to put AI in a top down Tactical Strategy game in Flash AS3. I decided that I would use a node based path finding approach because the game is based on a circular movement scheme. When a player moves a unit he essentially draws a series of line segments that connect that a player unit will follow along. I am trying to put together a similar operation for the AI units in our game by creating a list of nodes to traverse to a target node. Hence my use of Astar (the resulting path can be used to create this line). Here is my Algorithm function findShortestPath (startN:node, goalN:node) { var openSet:Array = new Array(); var closedSet:Array = new Array(); var pathFound:Boolean = false; startN.g_score = 0; startN.h_score = distFunction(startN,goalN); startN.f_score = startN.h_score; startN.fromNode = null; openSet.push (startN); var i:int = 0 for(i= 0; i< nodeArray.length; i++) { for(var j:int =0; j<nodeArray[0].length; j++) { if(!nodeArray[i][j].isPathable) { closedSet.push(nodeArray[i][j]); } } } while (openSet.length != 0) { var cNode:node = openSet.shift(); if (cNode == goalN) { resolvePath (cNode); return true; } closedSet.push (cNode); for (i= 0; i < cNode.dirArray.length; i++) { var neighborNode:node = cNode.nodeArray[cNode.dirArray[i]]; if (!(closedSet.indexOf(neighborNode) == -1)) { continue; } neighborNode.fromNode = cNode; var tenativeg_score:Number = cNode.gscore + distFunction(neighborNode.fromNode,neighborNode); if (openSet.indexOf(neighborNode) == -1) { neighborNode.g_score = neighborNode.fromNode.g_score + distFunction(neighborNode,cNode); if (cNode.dirArray[i] >= 4) { neighborNode.g_score -= 4; } neighborNode.h_score=distFunction(neighborNode,goalN); neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; insertIntoPQ (neighborNode, openSet); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); } else if (tenativeg_score <= neighborNode.g_score) { neighborNode.fromNode=cNode; neighborNode.g_score=cNode.g_score+distFunction(neighborNode,cNode); if (cNode.dirArray[i]>=4) { neighborNode.g_score-=4; } neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; openSet.splice (openSet.indexOf(neighborNode),1); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); insertIntoPQ (neighborNode, openSet); } } } trace ("fail"); return false; } Right now this function creates paths that are often not optimal or wholly inaccurate given the target and this generally happens when I have nodes that are not path able, and I am not quite sure what I am doing wrong right now. If someone could help me correct this I would appreciate it greatly. Some Notes My OpenSet is essentially a Priority Queue, so thats how I sort my nodes by cost. Here is that function function insertIntoPQ (iNode:node, pq:Array) { var inserted:Boolean=true; var iterater:int=0; while (inserted) { if (iterater==pq.length) { pq.push (iNode); inserted=false; } else if (pq[iterater].f_score >= iNode.f_score) { pq.splice (iterater,0,iNode); inserted=false; } ++iterater; } } Thanks!

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• Boost::Spirit::Qi autorules -- avoiding repeated copying of AST data structures

  - by phooji

  I've been using Qi and Karma to do some processing on several small languages. Most of the grammars are pretty small (20-40 rules). I've been able to use autorules almost exclusively, so my parse trees consist entirely of variants, structs, and std::vectors. This setup works great for the common case: 1) parse something (Qi), 2) make minor manipulations to the parse tree (visitor), and 3) output something (Karma). However, I'm concerned about what will happen if I want to make complex structural changes to a syntax tree, like moving big subtrees around. Consider the following toy example: A grammar for s-expr-style logical expressions that uses autorules... // Inside grammar class; rule names match struct names... pexpr %= pand | por | var | bconst; pand %= lit("(and ") >> (pexpr % lit(" ")) >> ")"; por %= lit("(or ") >> (pexpr % lit(" ")) >> ")"; pnot %= lit("(not ") >> pexpr >> ")"; ... which leads to parse tree representation that looks like this... struct var { std::string name; }; struct bconst { bool val; }; struct pand; struct por; struct pnot; typedef boost::variant<bconst, var, boost::recursive_wrapper<pand>, boost::recursive_wrapper<por>, boost::recursive_wrapper<pnot> > pexpr; struct pand { std::vector<pexpr> operands; }; struct por { std::vector<pexpr> operands; }; struct pnot { pexpr victim; }; // Many Fusion Macros here Suppose I have a parse tree that looks something like this: pand / ... \ por por / \ / \ var var var var (The ellipsis means 'many more children of similar shape for pand.') Now, suppose that I want negate each of the por nodes, so that the end result is: pand / ... \ pnot pnot | | por por / \ / \ var var var var The direct approach would be, for each por subtree: - create pnot node (copies por in construction); - re-assign the appropriate vector slot in the pand node (copies pnot node and its por subtree). Alternatively, I could construct a separate vector, and then replace (swap) the pand vector wholesale, eliminating a second round of copying. All of this seems cumbersome compared to a pointer-based tree representation, which would allow for the pnot nodes to be inserted without any copying of existing nodes. My question: Is there a way to avoid copy-heavy tree manipulations with autorule-compliant data structures? Should I bite the bullet and just use non-autorules to build a pointer-based AST (e.g., http://boost-spirit.com/home/2010/03/11/s-expressions-and-variants/)?

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• Drupal Modules for SEO & Content

  - by Aditi

  When we talk about Drupal SEO, there are two things to consider one is about the relevant SEO practices and about appropriate Drupal Modules available. Optimizing your website for search engines is one of the most important aspect of launching & promoting your website especially if ranking matters to you. Understanding SEO For starters, you have begin with Keyword research and then optimize your content according to your findings by tagging, meta tags etc, Drupal modules once installed help you manage a lot of such parameters. Identifying the target keywords Using the Page Title and Token modules PathAuto configuration <H1> heading tags Optimizing Drupal’s default robots.txt file Etc. While Drupal gives you a lot of ability to make your website content worthy & search engine friendly it is important for you to make sure you are not crossing the line or you could get penalized. Modules Overview Drupal Power is at its best when you have these modules & great brain working together. The basic SEO improvements can be achieved easily with the modules enlisted below, but you can win magical rankings if you use them logically & wisely. Understanding your keyword competition & enhancing your content is the basic key to success and ofcourse the modules: Pathauto Automatically create search enging friendly readable URLS from tokens. A token is a piece of data from content, say the author’s username, or the content’s title. For example mysite.com/an-article, rather than mysite.com/node/114 for every node you make. NodeWords Amazingly useful drupal module that allows you to create custom meta tags and descriptions for your nodes, which gives you the ability to target specific keywords and phrases. Page Title Enables you to set an alternative title for the <title></title> tags and for the <h1></h1> tags on a node. Global Redirect Manage content duplication, 301 redirects, and URL validation with this small, but powerful module. Taxonomy manager Make large additions, or changes to taxonomy very easy. This module provides a powerful interface for managing taxonomies. A vocabulary gets displayed in a dynamic tree view, where parent terms can be expanded to list their nested child terms or can be collapsed. robotstxt A robots.txt file is vital for ensuring that search engine spiders don’t index the unwanted areas of your site. This Drupal module gives you the ability to manage your robots.txt file through the CMS admin. xmlsitemap An XML Sitemap lets the search engines index your website content. This module helps in generating and maintaining a complete sitemap for your website and gives you control over exactly which parts of the site you want to be included in the index. It even gives you the ability to automatically submit your sitemap to Google, Yahoo!, Ask.com and Windows Live every time you update a node or at specific interval. Node Import This module allows you to import a set of nodes from a Comma Seperated Values (CSV) or Tab Seperated Values (TSV) text file. Makes it easy to import hundreds-thousands of csv rows and you get to tie up these rows to CCK fields (or locations), and it can file it under the right taxonomy hierarchy. This is Super life saver module.

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• Problem with AssetManager while loading a Model type

  - by user1204548

  Today I've tried the AssetManager for the first time with .g3db files and I'm having some problems. Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load dependencies of asset: data/data at com.badlogic.gdx.assets.AssetManager.handleTaskError(AssetManager.java:508) at com.badlogic.gdx.assets.AssetManager.update(AssetManager.java:342) at com.lostchg.martagdx3d.MartaGame.render(MartaGame.java:78) at com.badlogic.gdx.Game.render(Game.java:46) at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:207) at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114) Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load dependencies of asset: data/data at com.badlogic.gdx.assets.AssetLoadingTask.handleAsyncLoader(AssetLoadingTask.java:119) at com.badlogic.gdx.assets.AssetLoadingTask.update(AssetLoadingTask.java:89) at com.badlogic.gdx.assets.AssetManager.updateTask(AssetManager.java:445) at com.badlogic.gdx.assets.AssetManager.update(AssetManager.java:340) ... 4 more Caused by: com.badlogic.gdx.utils.GdxRuntimeException: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load file: data/data at com.badlogic.gdx.utils.async.AsyncResult.get(AsyncResult.java:31) at com.badlogic.gdx.assets.AssetLoadingTask.handleAsyncLoader(AssetLoadingTask.java:117) ... 7 more Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load file: data/data at com.badlogic.gdx.graphics.Pixmap.<init>(Pixmap.java:140) at com.badlogic.gdx.assets.loaders.TextureLoader.loadAsync(TextureLoader.java:72) at com.badlogic.gdx.assets.loaders.TextureLoader.loadAsync(TextureLoader.java:41) at com.badlogic.gdx.assets.AssetLoadingTask.call(AssetLoadingTask.java:69) at com.badlogic.gdx.assets.AssetLoadingTask.call(AssetLoadingTask.java:34) at com.badlogic.gdx.utils.async.AsyncExecutor$2.call(AsyncExecutor.java:49) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: com.badlogic.gdx.utils.GdxRuntimeException: File not found: data\data (Internal) at com.badlogic.gdx.files.FileHandle.read(FileHandle.java:132) at com.badlogic.gdx.files.FileHandle.length(FileHandle.java:586) at com.badlogic.gdx.files.FileHandle.readBytes(FileHandle.java:220) at com.badlogic.gdx.graphics.Pixmap.<init>(Pixmap.java:137) ... 9 more Why it tries to load that unexisting file? It seems that the AssetManager manages to load my .g3db file at first, because earlier the java console threw some errors related to the textures associated to the 3D scene having to be a power of 2. Relevant code: public void show() { ... assets = new AssetManager(); assets.load("data/levelprueba2.g3db", Model.class); loading = true; ... } private void doneLoading() { Model model = assets.get("data/levelprueba2.g3db", Model.class); for (int i = 0; i < model.nodes.size; i++) { String id = model.nodes.get(i).id; ModelInstance instance = new ModelInstance(model, id); Node node = instance.getNode(id); instance.transform.set(node.globalTransform); node.translation.set(0,0,0); node.scale.set(1,1,1); node.rotation.idt(); instance.calculateTransforms(); instances.add(instance); } loading = false; } public void render(float delta) { super.render(delta); if (loading && assets.update()) doneLoading(); ... } The error points to the line with the assets.update() method. Please, help! Sorry for my bad English and my amateurish doubts.

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• Best Design Pattern for Coupling User Interface Components and Data Structures

  - by szahn

  I have a windows desktop application with a tree view. Due to lack of a sound data-binding solution for a tree view, I've implemented my own layer of abstraction on it to bind nodes to my own data structure. The requirements are as follows: Populate a tree view with nodes that resemble fields in a data structure. When a node is clicked, display the appropriate control to modify the value of that property in the instance of the data structure. The tree view is populated with instances of custom TreeNode classes that inherit from TreeNode. The responsibility of each custom TreeNode class is to (1) format the node text to represent the name and value of the associated field in my data structure, (2) return the control used to modify the property value, (3) get the value of the field in the control (3) set the field's value from the control. My custom TreeNode implementation has a property called "Control" which retrieves the proper custom control in the form of the base control. The control instance is stored in the custom node and instantiated upon first retrieval. So each, custom node has an associated custom control which extends a base abstract control class. Example TreeNode implementation: //The Tree Node Base Class public abstract class TreeViewNodeBase : TreeNode { public abstract CustomControlBase Control { get; } public TreeViewNodeBase(ExtractionField field) { UpdateControl(field); } public virtual void UpdateControl(ExtractionField field) { Control.UpdateControl(field); UpdateCaption(FormatValueForCaption()); } public virtual void SaveChanges(ExtractionField field) { Control.SaveChanges(field); UpdateCaption(FormatValueForCaption()); } public virtual string FormatValueForCaption() { return Control.FormatValueForCaption(); } public virtual void UpdateCaption(string newValue) { this.Text = Caption; this.LongText = newValue; } } //The tree node implementation class public class ExtractionTypeNode : TreeViewNodeBase { private CustomDropDownControl control; public override CustomControlBase Control { get { if (control == null) { control = new CustomDropDownControl(); control.label1.Text = Caption; control.comboBox1.Items.Clear(); control.comboBox1.Items.AddRange( Enum.GetNames( typeof(ExtractionField.ExtractionType))); } return control; } } public ExtractionTypeNode(ExtractionField field) : base(field) { } } //The custom control base class public abstract class CustomControlBase : UserControl { public abstract void UpdateControl(ExtractionField field); public abstract void SaveChanges(ExtractionField field); public abstract string FormatValueForCaption(); } //The custom control generic implementation (view) public partial class CustomDropDownControl : CustomControlBase { public CustomDropDownControl() { InitializeComponent(); } public override void UpdateControl(ExtractionField field) { //Nothing to do here } public override void SaveChanges(ExtractionField field) { //Nothing to do here } public override string FormatValueForCaption() { //Nothing to do here return string.Empty; } } //The custom control specific implementation public class FieldExtractionTypeControl : CustomDropDownControl { public override void UpdateControl(ExtractionField field) { comboBox1.SelectedIndex = comboBox1.FindStringExact(field.Extraction.ToString()); } public override void SaveChanges(ExtractionField field) { field.Extraction = (ExtractionField.ExtractionType) Enum.Parse(typeof(ExtractionField.ExtractionType), comboBox1.SelectedItem.ToString()); } public override string FormatValueForCaption() { return string.Empty; } The problem is that I have "generic" controls which inherit from CustomControlBase. These are just "views" with no logic. Then I have specific controls that inherit from the generic controls. I don't have any functions or business logic in the generic controls because the specific controls should govern how data is associated with the data structure. What is the best design pattern for this?

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• Blueprints for Oracle NoSQL Database

  - by dan.mcclary

  I think that some of the most interesting analytic problems are graph problems.  I'm always interested in new ways to store and access graphs.  As such, I really like the work being done by Tinkerpop to create Open Source Software to make property graphs more accessible over a wide variety of datastores.  Since key-value stores like Oracle NoSQL Database are well-suited to storing property graphs, I decided to extend the Blueprints API to work with it.  Below I'll discuss some of the implementation details, but you can check out the finished product here: http://github.com/dwmclary/blueprints-oracle-nosqldb.  What's in a Property Graph?  In the most general sense, a graph is just a collection of vertices and edges.  Vertices and edges can have properties: weights, names, or any number of other traits.  In an undirected graph, edges connect vertices without direction.  A directed graph specifies that all edges have a head and a tail --- a direction.  A multi-graph allows multiple edges to connect two vertices.  A "property graph" encompasses all of these traits. Key-Value Stores for Property Graphs Key-Value stores like Oracle NoSQL Database tend to be ideal for implementing property graphs.  First, if any vertex or edge can have any number of traits, we can treat it as a hash map.  For example: Vertex["name"] = "Mary" Vertex["age"] = 28 Vertex["ID"] = 12345  and so on.  This is a natural key-value relationship: the key "name" maps to the value "Mary."  Moreover if we maintain two hash maps, one for vertex objects and one for edge objects, we've essentially captured the graph.  As such, any scalable key-value store is fertile ground for planting graphs. Oracle NoSQL Database as a Scalable Graph Database While Oracle NoSQL Database offers useful features like tunable consistency, what lends it to storing property graphs is the storage guarantees around its key structure.  Keys in Oracle NoSQL Database are divided into two parts: a major key and a minor key.  The storage guarantee is simple.  Major keys will be distributed across storage nodes, which could encompass a large number of servers.  However, all minor keys which are children of a given major key are guaranteed to be stored on the same storage node.  For example, the vertices: /Personnel/Vertex/1  and /Personnel/Vertex/2 May be stored on different servers, but /Personnel/Vertex/1-/name and  /Personnel/Vertex/1-/age will always be on the same server.  This means that we can structure our graph database such that retrieving all the properties for a vertex or edge requires I/O from only a single storage node.  Moreover, Oracle NoSQL Database provides a storeIterator which allows us to store a huge number of vertices and edges in a scalable fashion.  By storing the vertices and edges as major keys, we guarantee that they are distributed evenly across all storage nodes.  At the same time we can use a partial major key to iterate over all the vertices or edges (e.g. we search over /Personnel/Vertex to iterate over all vertices). Fork It! The Blueprints API and Oracle NoSQL Database present a great way to get started using a scalable key-value database to store and access graph data.  However, a graph store isn't useful without a good graph to work on.  I encourage you to fork or pull the repository, store some data, and try using Gremlin or any other language to explore.

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• Social Technology and the Potential for Organic Business Networks

  - by Michael Snow

  Guest Blog Post by:  Michael Fauscette, IDCThere has been a lot of discussion around the topic of social business, or social enterprise, over the last few years. The concept of applying emerging technologies from the social Web, combined with changes in processes and culture, has the potential to provide benefits across the enterprise over a wide range of operations impacting employees, customers, partners and suppliers. Companies are using social tools to build out enterprise social networks that provide, among other things, a people-centric collaborative and knowledge sharing work environment which over time can breakdown organizational silos. On the outside of the business, social technology is adding new ways to support customers, market to prospects and customers, and even support the sales process. We’re also seeing new ways of connecting partners to the business that increases collaboration and innovation. All of the new "connectivity" is, I think, leading businesses to a business model built around the concept of the network or ecosystem instead of the old "stand-by-yourself" approach. So, if you think about businesses as networks in the context of all of the other technical and cultural change factors that we're seeing in the new information economy, you can start to see that there’s a lot of potential for co-innovation and collaboration that was very difficult to arrange before. This networked business model, or what I've started to call “organic business networks,” is the business model of the information economy.The word “organic” could be confusing, but when I use it in this context, I’m thinking it has similar traits to organic computing. Organic computing is a computing system that is self-optimizing, self-healing, self-configuring, and self-protecting. More broadly, organic models are generally patterns and methods found in living systems used as a metaphor for non-living systems.Applying an organic model, organic business networks are networks that represent the interconnectedness of the emerging information business environment. Organic business networks connect people, data/information, content, and IT systems in a flexible, self-optimizing, self-healing, self-configuring, and self-protecting system. People are the primary nodes of the network, but the other nodes — data, content, and applications/systems — are no less important.A business built around the organic business network business model would incorporate the characteristics of a social business, but go beyond the basics—i.e., use social business as the operational paradigm, but also use organic business networks as the mode of operating the business. The two concepts complement each other: social business is the “what,” and the organic business network is the “how.”An organic business network lets the business work go outside of traditional organizational boundaries and become the continuously adapting implementation of an optimized business strategy. Value creation can move to the optimal point in the network, depending on strategic influencers such as the economy, market dynamics, customer behavior, prospect behavior, partner behavior and needs, supply-chain dynamics, predictive business outcomes, etc.An organic business network driven company is the antithesis of a hierarchical, rigid, reactive, process-constrained, and siloed organization. Instead, the business can adapt to changing conditions, leverage assets effectively, and thrive in a hyper-connected, global competitive, information-driven environment.To hear more on this topic – I’ll be presenting in the next webcast of the Oracle Social Business Thought Leader Webcast Series - “Organic Business Networks: Doing Business in a Hyper-Connected World” this coming Thursday, June 21, 2012, 10:00 AM PDT – Register here

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• Big Data – Interacting with Hadoop – What is Sqoop? – What is Zookeeper? – Day 17 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned the importance of the Pig and Pig Latin in Big Data Story. In this article we will understand what is Sqoop and Zookeeper in Big Data Story. There are two most important components one should learn when learning about interacting with Hadoop – Sqoop and Zookper. What is Sqoop? Most of the business stores their data in RDBMS as well as other data warehouse solutions. They need a way to move data to the Hadoop system to do various processing and return it back to RDBMS from Hadoop system. The data movement can happen in real time or at various intervals in bulk. We need a tool which can help us move this data from SQL to Hadoop and from Hadoop to SQL. Sqoop (SQL to Hadoop) is such a tool which extract data from non-Hadoop data sources and transform them into the format which Hadoop can use it and later it loads them into HDFS. Essentially it is ETL tool where it Extracts, Transform and Load from SQL to Hadoop. The best part is that it also does extract data from Hadoop and loads them to Non-SQL (or RDBMS) data stores. Essentially, Sqoop is a command line tool which does SQL to Hadoop and Hadoop to SQL. It is a command line interpreter. It creates MapReduce job behinds the scene to import data from an external database to HDFS. It is very effective and easy to learn tool for nonprogrammers. What is Zookeeper? ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. In other words Zookeeper is a replicated synchronization service with eventual consistency. In simpler words – in Hadoop cluster there are many different nodes and one node is master. Let us assume that master node fails due to any reason. In this case, the role of the master node has to be transferred to a different node. The main role of the master node is managing the writers as that task requires persistence in order of writing. In this kind of scenario Zookeeper will assign new master node and make sure that Hadoop cluster performs without any glitch. Zookeeper is the Hadoop’s method of coordinating all the elements of these distributed systems. Here are few of the tasks which Zookeepr is responsible for. Zookeeper manages the entire workflow of starting and stopping various nodes in the Hadoop’s cluster. In Hadoop cluster when any processes need certain configuration to complete the task. Zookeeper makes sure that certain node gets necessary configuration consistently. In case of the master node fails, Zookeepr can assign new master node and make sure cluster works as expected. There many other tasks Zookeeper performance when it is about Hadoop cluster and communication. Basically without the help of Zookeeper it is not possible to design any new fault tolerant distributed application. Tomorrow In tomorrow’s blog post we will discuss about very important components of the Big Data Ecosystem – Big Data Analytics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Would this be a good web application architecture?

  - by Gustav Bertram

  My problem Our MVC based framework does not allow us to cache only part of our output. Ideally we want to cahce static and semi-static bits, and run dynamic bits. In addition, we need to consider data caching that reacts to database changes. My idea The concept I came up with was to represent a page as a tree of XML fragment objects. (I say XML, but I mean XHTML). Some of the fragments are dynamic, and can pull their data directly from models or other sources, but most of the fragments are static scaffolding. If a subtree of fragments is completely static, then I imagine that they could unfold into pure XML that would then be cached as the text representation of their parent element. This process would ideally continue until we are left with a root element that contains all of the static XML, and has a couple of dynamic XML fragments that are resolved and attached to the relevant nodes of the XML tree just before the page is displayed. In addition to separating content into dynamic and static fragments, some fragments could be dynamic and cached. A simple expiry time which propagates up through the XML fragment tree would indicate that a specific fragment should periodically be refreshed. A newspaper section or front page does not need to be updated each second. Minutes or sometimes even longer is sufficient. Other fragments would be dynamic and uncached. Typically too many articles are viewed for them to be cached - the cache would overflow. Some individual articles may be cached if they are extremely popular. Functional notes The folding mechanism could be to be smart enough to judge when it would be more profitable to fold a dynamic cached fragment and propagate the expiry date to the parent fragment, or to keep it separate and simple attach to the XML tree when resolving the page. If some dynamic cached fragments are associated to database objects through mechanisms like a globally unique content id, then changes to the database could trigger changes to the output cache. If fragments store the identifiers of parent fragments, then they could trigger a refolding process that would then include the updated data. A set of pure XML with an ordered array of fragment objects (that each store the identifying information of the node to which they should be attached), can be resolved in a fairly simple way by walking the XML tree, and merging the data from the fragments. Because it is not necessary to parse and construct the entire tree in memory before attaching nodes, processing should be fairly fast. The identifiers of each fragment would be a combination of relevant identity data and the type of fragment object. Cached parent fragments would contain references to these identifiers, in order to then either pull them from the fragment cache, or to run their code. The controller's responsibility is reduced to making changes to the database, and telling the root XML fragment object to render itself. The Question My question has two parts: Is this a good design? Are there any obvious flaws I'm missing? Has somebody else thought of this before? References? Is there an existing alternative that I should consider? A cool templating engine maybe?

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• Reading graph inputs for a programming puzzle and then solving it

  - by Vrashabh

  I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle http://codercharts.com/puzzle/evacuation-plan but also had an hour component in the first line(say 3 hours after start of evacuation). It reads like this This puzzle is a tribute to all the people who suffered from the earthquake in Japan. The goal of this puzzle is, given a network of road and locations, to determine the maximum number of people that can be evacuated. The people must be evacuated from evacuation points to rescue points. The list of road and the number of people they can carry per hour is provided. Input Specifications Your program must accept one and only one command line argument: the input file. The input file is formatted as follows: the first line contains 4 integers n r s t n is the number of locations (each location is given by a number from 0 to n-1) r is the number of roads s is the number of locations to be evacuated from (evacuation points) t is the number of locations where people must be evacuated to (rescue points) the second line contains s integers giving the locations of the evacuation points the third line contains t integers giving the locations of the rescue points the r following lines contain to the road definitions. Each road is defined by 3 integers l1 l2 width where l1 and l2 are the locations connected by the road (roads are one-way) and width is the number of people per hour that can fit on the road Now look at the sample input set 5 5 1 2 3 0 3 4 0 1 10 0 2 5 1 2 4 1 3 5 2 4 10 The 3 in the first line is the additional component and is defined as the number of hours since the resuce has started which is 3 in this case. Now my solution was to use Dijisktras algorithm to find the shortest path between each of the rescue and evac nodes. Now my problem started with how to read the input set. I read the first line in python and stored the values in variables. But then I did not know how to store the values of the distance between the nodes and what DS to use and how to input it to say a standard implementation of dijikstras algorithm. So my question is two fold 1.) How do I take the input of such problems? - I have faced this problem in quite a few competitions recently and I hope I can get a simple code snippet or an explanation in java or python to read the data input set in such a way that I can input it as a graph to graph algorithms like dijikstra and floyd/warshall. Also a solution to the above problem would also help. 2.) How to solve this puzzle? My algorithm was: Find shortest path between evac points (in the above example it is 14 from 0 to 3) Multiply it by number of hours to get maximal number of saves Also the answer given for the variant for the input set was 24 which I dont understand. Can someone explain that also. UPDATE: I get how the answer is 14 in the given problem link - it seems to be just the shortest path between node 0 and 3. But with the 3 hour component how is the answer 24 UPDATE I get how it is 24 - its a complete graph traversal at every hour and this is how I solve it Hour 1 Node 0 to Node 1 - 10 people Node 0 to Node 2- 5 people TotalRescueCount=0 Node 1=10 Node 2= 5 Hour 2 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5(Rescued) Node 0 to Node 1 = 10 Node 0 to Node 2 = 5 Node 1 to Node 2 = 4 TotalRescueCount = 10 Node 1 = 10 Node 2= 5+4 = 9 Hour 3 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5+4 = 9(Rescued) TotalRescueCount = 9+5+10 = 24 It hard enough for this case , for multiple evac and rescue points how in the world would I write a pgm for this ?

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• Synchronizing Asynchronous request handlers in Silverlight environment

  - by Eric Lifka

  For our senior design project my group is making a Silverlight application that utilizes graph theory concepts and stores the data in a database on the back end. We have a situation where we add a link between two nodes in the graph and upon doing so we run analysis to re-categorize our clusters of nodes. The problem is that this re-categorization is quite complex and involves multiple queries and updates to the database so if multiple instances of it run at once it quickly garbles data and breaks (by trying to re-insert already used primary keys). Essentially it's not thread safe, and we're trying to make it safe, and that's where we're failing and need help :). The create link function looks like this: private Semaphore dblock = new Semaphore(1, 1); // This function is on our service reference and gets called // by the client code. public int addNeed(int nodeOne, int nodeTwo) { dblock.WaitOne(); submitNewNeed(createNewNeed(nodeOne, nodeTwo)); verifyClusters(nodeOne, nodeTwo); dblock.Release(); return 0; } private void verifyClusters(int nodeOne, int nodeTwo) { // Run analysis of nodeOne and nodeTwo in graph } All copies of addNeed should wait for the first one that comes in to finish before another can execute. But instead they all seem to be running and conflicting with each other in the verifyClusters method. One solution would be to force our front end calls to be made synchronously. And in fact, when we do that everything works fine, so the code logic isn't broken. But when it's launched our application will be deployed within a business setting and used by internal IT staff (or at least that's the plan) so we'll have the same problem. We can't force all clients to submit data at different times, so we really need to get it synchronized on the back end. Thanks for any help you can give, I'd be glad to supply any additional information that you could need!

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• ArgumentError: Error #2004: One of the parameters is invalid.

  - by Florian

  I got the following stack trace while running a piece of code in my flex application: ArgumentError: Error #2004: One of the parameters is invalid. at ObjectOutput/writeObject() at mx.collections::ArrayList/writeExternal()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\collections\ArrayList.as:470] at mx.collections::ArrayCollection/writeExternal()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\collections\ArrayCollection.as:144] at flash.utils::ByteArray/writeObject() at mx.utils::ObjectUtil$/copy()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\utils\ObjectUtil.as:100] at components::SettingsHandler/saveOpenNodes()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\SettingsHandler.as:153] at components::soapjira/getIssuesByFilters()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\soapjira.as:295] at components.tabs::JiraAllActions/loadData()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\tabs\JiraAllActions.mxml:193] at components::SettingsHandler/settingsClosed()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\SettingsHandler.as:114] at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\UIComponent.as:9408] at components.general::JiraSettings/closeSettings()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\general\JiraSettings.mxml:58] at components.general::JiraSettings/__save_click()[C:\workspaces\Intranets\UniqueInbox\flex_src\components\general\JiraSettings.mxml:107] That stack comes up when running the following line (SettingsHandler.as:153): var tmp:Object = parentComponent.dataGrid.dataProvider.openNodes; I am actually copying the open nodes of a datagrid's provider. Has been working until now and just started going wrong, no idea what I have changed that could interfere with this. On debug mode, I see that openNodes is accessible and contains the open nodes, as expected. Doing tmp:Object = parentComponent.dataGrid.dataProvider.openNodes works, but not with ObjectUtil. (parentComponent is the reference to the component which contains the DG).

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• IDEA modular problem (jsp)

  - by Jeriho

  I have project in with 2 separate modules(frontend and backend, first depends on second). When I'm trying to access backend code from frontend code, things going fine. Things turn for the worse when I do the same from jsp. This is stacktrase for simple accessign bean <jsp:useBean id="mybean" class="backend.main.MyBean" scope="request"></jsp:useBean> org.apache.jasper.JasperException: /results.jsp(9,0) The value for the useBean class attribute backend.main.MyBean is invalid. org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40) org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407) org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:148) org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1220) org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1178) org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361) org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2411) org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2417) org.apache.jasper.compiler.Node$Root.accept(Node.java:495) org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361) org.apache.jasper.compiler.Generator.generate(Generator.java:3416) org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:231) org.apache.jasper.compiler.Compiler.compile(Compiler.java:347) org.apache.jasper.compiler.Compiler.compile(Compiler.java:327) org.apache.jasper.compiler.Compiler.compile(Compiler.java:314) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:589) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) And this error will appear if I try to access regular class: An error occurred at line: 12 in the jsp file: /results.jsp backend.main.RegularClass cannot be resolved to a type Stacktrace: org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92) org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330) org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:439) org.apache.jasper.compiler.Compiler.compile(Compiler.java:349) org.apache.jasper.compiler.Compiler.compile(Compiler.java:327) org.apache.jasper.compiler.Compiler.compile(Compiler.java:314) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:589) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) Sorry for so many stacktraces.

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• How to correctly refactor this?

  - by kane77

  I have trouble finding way to correctly refactor this code so that there would be as little duplicate code as possible, I have a couple of methods like this (pseudocode): public List<Something> parseSomething(Node n){ List<Something> somethings = new ArrayList<Something>(); initialize(); sameCodeInBothClasses(); List<Node> nodes = getChildrenByName(n, "somename"); for(Node n:nodes){ method(); actionA(); somethings.add(new Something(actionB()); } return somethings; } methods sameCodeInBothClasses() are same in all classes but where it differs is what hapens in for loop actionA() and it also adds an element to the List of different type. Should I use Strategy pattern for the different parts inside loop? What about the return value (The type of list differs), should the method return just List<Object> that I would then cast to appropriate type? Should I pass the class I want to return as parameter?

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• Thrift,.NET,Cassandra - Is this is right combination?

  - by Vadi

  I've been evaluating technology stack for developing a social network based application. Below are the stack I think could well suitable for this application type of application: GUI -- ASP.NET MVC, Flash (Flex) Business Services -- Thrift based services One of the advantage of using Thrift is to solve scaling problems that will come in future when the user base increases rapidly. All the business logic can be exposed as a services using REST,JSON etc., This also allows us to go with C++ or Erlang based services when situation demands. Database -- mySQL, CasSandara mySQL can be used for storing the data which needs to be persisted. Cassandara will be used for storing global identifiers to the persisted data. Since Cassandara is also very good at scaling by introducing more nodes this will leverage Thrift based services as well. And also there is native support between Cassandara and Thrift Cache Server -- Memcached Any requests from Business Services will only talk to Memcached if any non-dirty data is required, otherwise there will be some background jobs that will invalidate the cache from database. The question is: Is the Thrift which is open-sourced one is production-ready? Is it the right stack for services layer to choose when the application (GUI) is primarily gets developed in ASP.NET and DB is mysql? Is there any other caveats that anyone here experienced? One of the main objective behind this stack is to easily scale up with more nodes and also this helps us to use Linux boxes, it will reduce our cost significantly Thoughts please ..

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• XmlDocument SelectNodes(Xpath): Order of result

  - by crauscher

  This is an example xml from MSDN <?xml version="1.0"?> <!-- A fragment of a book store inventory database --> <bookstore xmlns:bk="urn:samples"> <book genre="novel" publicationdate="1997" bk:ISBN="1-861001-57-8"> <title>Pride And Prejudice</title> </book> <book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1"> <title>The Handmaid's Tale</title> </book> <book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6"> <title>Emma</title> </book> <book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3"> <title>Sense and Sensibility</title> </book> </bookstore> When I select all book nodes using the following code, which order will these nodes have? XmlDocument doc = new XmlDocument(); doc.Load("booksort.xml"); var nodeList =doc.SelectNodes("bookstore/book"); Will the order of the items in the nodelist be the same as the order in the xml? Is this order guaranteed?

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• local variable 'sresult' referenced before assignment

  - by user288558

  I have had multiple problems trying to use PP. I am running python2.6 and pp 1.6.0 rc3. Using the following test code: import pp nodes=('mosura02','mosura03','mosura04','mosura05','mosura06', 'mosura09','mosura10','mosura11','mosura12') def pptester(): js=pp.Server(ppservers=nodes) tmp=[] for i in range(200): tmp.append(js.submit(ppworktest,(),(),('os',))) return tmp def ppworktest(): return os.system("uname -a") gives me the following result: In [10]: Exception in thread run_local: Traceback (most recent call last): File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner self.run() File "/usr/lib64/python2.6/threading.py", line 477, in run self.__target(*self.__args, **self.__kwargs) File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local job.finalize(sresult) UnboundLocalError: local variable 'sresult' referenced before assignment Exception in thread run_local: Traceback (most recent call last): File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner self.run() File "/usr/lib64/python2.6/threading.py", line 477, in run self.__target(*self.__args, **self.__kwargs) File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local job.finalize(sresult) UnboundLocalError: local variable 'sresult' referenced before assignment Exception in thread run_local: Traceback (most recent call last): File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner self.run() File "/usr/lib64/python2.6/threading.py", line 477, in run self.__target(*self.__args, **self.__kwargs) File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local job.finalize(sresult) UnboundLocalError: local variable 'sresult' referenced before assignment Exception in thread run_local: Traceback (most recent call last): File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner self.run() File "/usr/lib64/python2.6/threading.py", line 477, in run self.__target(*self.__args, **self.__kwargs) File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local job.finalize(sresult) UnboundLocalError: local variable 'sresult' referenced before assignment any help greatly appreciated

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• Starting an Erlang slave node in escript fails when using custom Erlang in Ubuntu 10.4

  - by Adam Lindberg

  I have the following escript: #!/usr/bin/env escript %%! -name [email protected] main(_) -> NodeName = test, Host = '127.0.0.1', Args = "", {ok, _Node} = slave:start_link(Host, NodeName, Args), io:format("Node started successfully!"). When running it on Ubuntu 10.04 I get this: $ ./start_slave Node started successfully! $ I want to install my own Erlang (latest version, debug compiled files for dialyzer etc) since the stock install of Erlang on Ubuntu lacks some features. I put my Erlang binaries inside ~/Applications/bin. Starting Erlang normally works, and starting slave nodes inside an Erlang shell works as well. However, now my escript doesn't work. After about 60 seconds it returns an error: $ ./start_slave escript: exception error: no match of right hand side value {error,timeout} Even if I change the first line to the escript to use my erlang version, it still does not work: #!/home/user/Applications/bin/escript The slave node is started with a call to erlang:open_port/2 which seems to be using sh which in turn does not read my .bashrc file that sets my custom PATH environment variable. The timeout seems to occur when slave:start_link/3 waits for the slave node to respond, which it never does. How can I roll my own installation of Erlang and start slave nodes inside escripts on Ubuntu 10.4?

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