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  • Help! I'm a Haskell Newbie

    - by Darknight
    I've only just dipped my toe in the world of Haskell as part of my journey of programming enlightenment (moving on from, procedural to OOP to concurrent to now functional). I've been trying an online Haskell Evaluator. However I'm now stuck on a problem: Create a simple function that gives the total sum of an array of numbers. In a procedural language this for me is easy enough (using recursion) (c#) : private int sum(ArrayList x, int i) { if (!(x.Count < i + 1)) { int t = 0; t = x.Item(i); t = sum(x, i + 1) + t; return t; } } All very fine however my failed attempt at Haskell was thus: let sum x = x+sum in map sum [1..10] this resulted in the following error (from that above mentioned website): Occurs check: cannot construct the infinite type: a = a -> t Please bear in mind I've only used Haskell for the last 30 minutes! I'm not looking simply for an answer but a more explanation of it. Thanks in advanced.

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  • How can I merge two Linq IEnumerable<T> queries without running them?

    - by makerofthings7
    How do I merge a List<T> of TPL-based tasks for later execution? public async IEnumerable<Task<string>> CreateTasks(){ /* stuff*/ } My assumption is .Concat() but that doesn't seem to work: void MainTestApp() // Full sample available upon request. { List<string> nothingList = new List<string>(); nothingList.Add("whatever"); cts = new CancellationTokenSource(); delayedExecution = from str in nothingList select AccessTheWebAsync("", cts.Token); delayedExecution2 = from str in nothingList select AccessTheWebAsync("1", cts.Token); delayedExecution = delayedExecution.Concat(delayedExecution2); } /// SNIP async Task AccessTheWebAsync(string nothing, CancellationToken ct) { // return a Task } I want to make sure that this won't spawn any task or evaluate anything. In fact, I suppose I'm asking "what logically executes an IQueryable to something that returns data"? Background Since I'm doing recursion and I don't want to execute this until the correct time, what is the correct way to merge the results if called multiple times? If it matters I'm thinking of running this command to launch all the tasks var AllRunningDataTasks = results.ToList(); followed by this code: while (AllRunningDataTasks.Count > 0) { // Identify the first task that completes. Task<TableResult> firstFinishedTask = await Task.WhenAny(AllRunningDataTasks); // ***Remove the selected task from the list so that you don't // process it more than once. AllRunningDataTasks.Remove(firstFinishedTask); // TODO: Await the completed task. var taskOfTableResult = await firstFinishedTask; // Todo: (doen't work) TrustState thisState = (TrustState)firstFinishedTask.AsyncState; // TODO: Update the concurrent dictionary with data // thisState.QueryStartPoint + thisState.ThingToSearchFor Interlocked.Decrement(ref thisState.RunningDirectQueries); Interlocked.Increment(ref thisState.CompletedDirectQueries); if (thisState.RunningDirectQueries == 0) { thisState.TimeCompleted = DateTime.UtcNow; } }

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  • Why are argument substitutions not replaced during rescanning?

    - by James McNellis
    Consider the following macro definitions and invocation: #define x x[0] #define y(arg) arg y(x) This invocation expands to x[0] (tested on Visual C++ 2010, g++ 4.1, mcpp 2.7.2, and Wave). Why? Specifically, why does it not expand to x[0][0]? During macro replacement, A parameter in the replacement list...is replaced by the corresponding argument after all macros contained therein have been expanded. Before being substituted, each argument’s preprocessing tokens are completely macro replaced (C++03 §16.3.1/1). Evaluating the macro invocation, we take the following steps: The function-like macro y is invoked with x as the argument for its arg parameter The x in the argument is macro-replaced to become x[0] The arg in the replacement list is replaced by the macro-replaced value of the argument, x[0] The replacement list after substitution of all the parameters is x[0]. After all parameters in the replacement list have been substituted, the resulting preprocessing token sequence is rescanned...for more macro names to replace (C++03 §16.3.4/1). If the name of the macro being replaced is found during this scan of the replacement list...it is not replaced. Further, if any nested replacements encounter the name of the macro being replaced, it is not replaced (C++03 §16.3.4/2). The replacement list x[0] is rescanned (note that the name of the macro being replaced is y): x is identified as an object-like macro invocation x is replaced by x[0] Replacement stops at this point because of the rule in §16.3.4/2 preventing recursion. The replacement list after rescanning is x[0][0]. I have clearly misinterpreted something since all of the preprocessors I've tested say I am wrong. In addition, this example is a piece of a larger example in the C++0x FCD (at §16.3.5/5) and it too says that the expected replacement is x[0]. Why is x not replaced during rescanning? C99 and C++0x effectively have the same wording as C++03 in the quoted sections.

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  • Java: Comparing a class with another within that class using a my own .equals

    - by user1670252
    I am making a method .equals replacing the equals method used. It accepts a object. I want it to check if that object equals the class that runs the .equals class. I know I want to compare all the private methods I have to that object. Is there a way to do this without making another private class to get the private variables from the object? How do I do this to compare equality not identity? I am stuck on this. Do i have to use == to compare? Also looking online i see others use recursion. If this is the way i have to do it can you show and explain it to me? so an example i have public boolean equals(Object o) { this is in a class we will call bobtheBuilder (first thing to pop in my head) I want to check if the object o is equal to the class he has private object array and a private int. I assume I want to check if the array and int of this class equal the array and int of the object.

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  • Convert a binary tree to linked list, breadth first, constant storage/destructive

    - by Merlyn Morgan-Graham
    This is not homework, and I don't need to answer it, but now I have become obsessed :) The problem is: Design an algorithm to destructively flatten a binary tree to a linked list, breadth-first. Okay, easy enough. Just build a queue, and do what you have to. That was the warm-up. Now, implement it with constant storage (recursion, if you can figure out an answer using it, is logarithmic storage, not constant). I found a solution to this problem on the Internet about a year back, but now I've forgotten it, and I want to know :) The trick, as far as I remember, involved using the tree to implement the queue, taking advantage of the destructive nature of the algorithm. When you are linking the list, you are also pushing an item into the queue. Each time I try to solve this, I lose nodes (such as each time I link the next node/add to the queue), I require extra storage, or I can't figure out the convoluted method I need to get back to a node that has the pointer I need. Even the link to that original article/post would be useful to me :) Google is giving me no joy. Edit: Jérémie pointed out that there is a fairly simple (and well known answer) if you have a parent pointer. While I now think he is correct about the original solution containing a parent pointer, I really wanted to solve the problem without it :) The refined requirements use this definition for the node: struct tree_node { int value; tree_node* left; tree_node* right; };

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  • Is it possible to wrap an asynchronous event and its callback in a function that returns a boolean?

    - by Rob Flaherty
    I'm trying to write a simple test that creates an image element, checks the image attributes, and then returns true/false. The problem is that using the onload event makes the test asynchronous. On it own this isn't a problem (using a callback as I've done in the code below is easy), but what I can't figure out is how to encapsulate this into a single function that returns a boolean. I've tried various combinations of closures, recursion, and self-executing functions but have had no luck. So my question: am I being dense and overlooking something simple, or is this in fact not possible, because, no matter what, I'm still trying to wrap an asynchronous function in synchronous expectations? Here's the code: var supportsImage = function(callback) { var img = new Image(); img.onload = function() { //Check attributes and pass true or false to callback callback(true); }; img.src = 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs='; }; supportsImage(function(status){ console.log(status); }); To be clear, what I want is to be able to wrap this in something such that it can be used like: if (supportsImage) { //Do some crazy stuff } Thanks! (Btw, I know there are a ton of SO questions regarding confusion about synchronous vs. asynchronous. Apologies if this can be reduced to something previously answered.)

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  • Need to sort 3 arrays by one key array

    - by jeff6461
    I am trying to get 3 arrays sorted by one key array in objective c for the iphone, here is a example to help out... Array 1 Array 2 Array 3 Array 4 1 15 21 7 3 12 8 9 6 7 8 0 2 3 4 8 When sorted i want this to look like Array 1 Array 2 Array 3 Array 4 1 15 21 7 2 3 4 8 3 12 8 9 6 7 8 0 So array 2,3,4 are moving with Array 1 when sorted. Currently i am using a bubble sort to do this but it lags so bad that it crashes by app. The code i am using to do this is int flag = 0; int i = 0; int temp = 0; do { flag=1; for(i = 0; i < distancenumber; i++) { if(distance[i] > distance[i+1]) { temp = distance[i]; distance[i]=distance[i + 1]; distance[i + 1]=temp; temp = FlowerarrayNumber[i]; FlowerarrayNumber[i] = FlowerarrayNumber[i+1]; FlowerarrayNumber[i + 1] = temp; temp = BeearrayNumber[i]; BeearrayNumber[i] = BeearrayNumber[i + 1]; BeearrayNumber[i + 1] = temp; flag=0; } } }while (flag==0); where distance number is the amount of elements in all of the arrays, distance is array 1 or my key array. and the other 2 are getting sorted. If anyone can help me get a merge sort(or something faster, it is running on a iPhone so it needs to be quick and light) to do this that would be great i cannot figure out how the recursion works in this method and so having a hard time to get the code to work. Any help would be greatly appreciated

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  • Best method to search heriarachal data

    - by WDuffy
    I'm looking at building a facility which allows querying for data with hierarchical filtering. I have a few ideas how I'm going to go about it but was wondering if there are any recommendations or suggestions that might be more efficient. As an example imagine that a user is searching for a job. The job areas would be as follows. 1: Scotland 2: --- West Central 3: ------ Glasgow 4: ------ Etc 5: --- North East 6: ------ Ayrshire 7: ------ Etc A user can search specific (ie Glasgow) or in a larger area (ie Scotland). The two approaches I am considering are 1: keep a note of children in the database for each record (ie cat 1 would have 2, 3, 4 in its children field) and query against that record with a SELECT * FROM Jobs WHERE Category IN Areas.childrenField. 2: Use a recursive function to find all results who have a relation to the selected area The problems I see from both are 1: holding this data in the db will mean having to keep track of all changes to structure 2: Recursion is slow and inefficent Any ideas, suggestion or recommendations on the best approach? I'm using C# ASP.NET with MSSQL 2005 DB.

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  • A generic Re-usable C# Property Parser utility

    - by Shyam K Pananghat
    This is about a utility i have happened to write which can parse through the properties of a data contracts at runtime using reflection. The input required is a look like XPath string. since this is using reflection, you dont have to add the reference to any of your data contracts thus making pure generic and re- usable.. you can read about this and get the full c# sourcecode here. Property-Parser-A-C-utility-to-retrieve-values-from-any-Net-Data-contracts-at-runtime Now about the doubts which i have about this utility. i am using this utility enormously i many places of my code I am using Regex repetedly inside a recursion method. does this affect the memmory usage or GC collection badly ?do i have to dispose this manually. if yes how ?. The statements like obj.GetType().GetProperty() and obj.GetType().GetField() returns .net "object" which makes difficult or imposible to introduce generics here. Does this cause to have any overheads like boxing ? on an overall, please suggest to make this utility performance efficient and more light weight on memmory

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  • Changing Value of Array Pointer When Passed to a Function

    - by ZAX
    I have a function which receives both the array, and a specific instance of the array. I try to change the specific instance of the array by accessing one of its members "color", but it does not actually change it, as can be seen by debugging (checking the value of color after function runs in the main program). I am hoping someone can help me to access this member and change it. Essentially I need the instance of the array I'm specifying to be passed by reference if nothing else, but I'm hoping there is an easier way to accomplish what I'm trying to do. Here's the structures: typedef struct adjEdge{ int vertex; struct adjEdge *next; } adjEdge; typedef struct vertex{ int sink; int source; int color; //0 will be white, 1 will be grey, 5 will be black int number; adjEdge *nextVertex; } vertex; And here is the function: void walk(vertex *vertexArray, vertex v, int source, maxPairing *head) { int i; adjEdge *traverse; int moveVertex; int sink; traverse = vertexArray[v.number-1].nextVertex; if(v.color != 5 && v.sink == 5) { sink = v.number; v.color = 5; addMaxPair(head, source, sink); } else { walk(vertexArray, vertexArray[traverse->vertex-1], source, head); } } In particular, v.color needs to be changed to a 5, that way later after recursion the if condition blocks it.

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  • GPGPU

    WhatGPU obviously stands for Graphics Processing Unit (the silicon powering the display you are using to read this blog post). The extra GP in front of that stands for General Purpose computing.So, altogether GPGPU refers to computing we can perform on GPU for purposes beyond just drawing on the screen. In effect, we can use a GPGPU a bit like we already use a CPU: to perform some calculation (that doesn’t have to have any visual element to it). The attraction is that a GPGPU can be orders of magnitude faster than a CPU.WhyWhen I was at the SuperComputing conference in Portland last November, GPGPUs were all the rage. A quick online search reveals many articles introducing the GPGPU topic. I'll just share 3 here: pcper (ignoring all pages except the first, it is a good consumer perspective), gizmodo (nice take using mostly layman terms) and vizworld (answering the question on "what's the big deal").The GPGPU programming paradigm (from a high level) is simple: in your CPU program you define functions (aka kernels) that take some input, can perform the costly operation and return the output. The kernels are the things that execute on the GPGPU leveraging its power (and hence execute faster than what they could on the CPU) while the host CPU program waits for the results or asynchronously performs other tasks.However, GPGPUs have different characteristics to CPUs which means they are suitable only for certain classes of problem (i.e. data parallel algorithms) and not for others (e.g. algorithms with branching or recursion or other complex flow control). You also pay a high cost for transferring the input data from the CPU to the GPU (and vice versa the results back to the CPU), so the computation itself has to be long enough to justify the overhead transfer costs. If your problem space fits the criteria then you probably want to check out this technology.HowSo where can you get a graphics card to start playing with all this? At the time of writing, the two main vendors ATI (owned by AMD) and NVIDIA are the obvious players in this industry. You can read about GPGPU on this AMD page and also on this NVIDIA page. NVIDIA's website also has a free chapter on the topic from the "GPU Gems" book: A Toolkit for Computation on GPUs.If you followed the links above, then you've already come across some of the choices of programming models that are available today. Essentially, AMD is offering their ATI Stream technology accessible via a language they call Brook+; NVIDIA offers their CUDA platform which is accessible from CUDA C. Choosing either of those locks you into the GPU vendor and hence your code cannot run on systems with cards from the other vendor (e.g. imagine if your CPU code would run on Intel chips but not AMD chips). Having said that, both vendors plan to support a new emerging standard called OpenCL, which theoretically means your kernels can execute on any GPU that supports it. To learn more about all of these there is a website: gpgpu.org. The caveat about that site is that (currently) it completely ignores the Microsoft approach, which I touch on next.On Windows, there is already a cross-GPU-vendor way of programming GPUs and that is the DirectX API. Specifically, on Windows Vista and Windows 7, the DirectX 11 API offers a dedicated subset of the API for GPGPU programming: DirectCompute. You use this API on the CPU side, to set up and execute the kernels that run on the GPU. The kernels are written in a language called HLSL (High Level Shader Language). You can use DirectCompute with HLSL to write a "compute shader", which is the term DirectX uses for what I've been referring to in this post as a "kernel". For a comprehensive collection of links about this (including tutorials, videos and samples) please see my blog post: DirectCompute.Note that there are many efforts to build even higher level languages on top of DirectX that aim to expose GPGPU programming to a wider audience by making it as easy as today's mainstream programming models. I'll mention here just two of those efforts: Accelerator from MSR and Brahma by Ananth. Comments about this post welcome at the original blog.

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  • Octree subdivision problem

    - by ChaosDev
    Im creating octree manually and want function for effectively divide all nodes and their subnodes - For example - I press button and subnodes divided - press again - all subnodes divided again. Must be like - 1 - 8 - 64. The problem is - i dont understand how organize recursive loops for that. OctreeNode in my unoptimized implementation contain pointers to subnodes(childs),parent,extra vector(contains dublicates of child),generation info and lots of information for drawing. class gOctreeNode { //necessary fields gOctreeNode* FrontBottomLeftNode; gOctreeNode* FrontBottomRightNode; gOctreeNode* FrontTopLeftNode; gOctreeNode* FrontTopRightNode; gOctreeNode* BackBottomLeftNode; gOctreeNode* BackBottomRightNode; gOctreeNode* BackTopLeftNode; gOctreeNode* BackTopRightNode; gOctreeNode* mParentNode; std::vector<gOctreeNode*> m_ChildsVector; UINT mGeneration; bool mSplitted; bool isSplitted(){return m_Splitted;} .... //unnecessary fields }; DivideNode of Octree class fill these fields, set mSplitted to true, and prepare for correctly drawing. Octree contains basic nodes(m_nodes). Basic node can be divided, but now I want recursivly divide already divided basic node with 8 subnodes. So I write this function. void DivideAllChildCells(int ix,int ih,int id) { std::vector<gOctreeNode*> nlist; std::vector<gOctreeNode*> dlist; int index = (ix * m_Height * m_Depth) + (ih * m_Depth) + (id * 1);//get index of specified node gOctreeNode* baseNode = m_nodes[index].get(); nlist.push_back(baseNode->FrontTopLeftNode); nlist.push_back(baseNode->FrontTopRightNode); nlist.push_back(baseNode->FrontBottomLeftNode); nlist.push_back(baseNode->FrontBottomRightNode); nlist.push_back(baseNode->BackBottomLeftNode); nlist.push_back(baseNode->BackBottomRightNode); nlist.push_back(baseNode->BackTopLeftNode); nlist.push_back(baseNode->BackTopRightNode); bool cont = true; UINT d = 0;//additional recursive loop param (?) UINT g = 0;//additional recursive loop param (?) LoopNodes(d,g,nlist,dlist); //Divide resulting nodes for(UINT i = 0; i < dlist.size(); i++) { DivideNode(dlist[i]); } } And now, back to the main question,I present LoopNodes, which must do all work for giving dlist nodes for splitting. void LoopNodes(UINT& od,UINT& og,std::vector<gOctreeNode*>& nlist,std::vector<gOctreeNode*>& dnodes) { //od++;//recursion depth bool f = false; //pass through childs for(UINT i = 0; i < 8; i++) { if(nlist[i]->isSplitted())//if node splitted and have childs { //pass forward through tree for(UINT j = 0; j < 8; j++) { nlist[j] = nlist[j]->m_ChildsVector[j];//set pointers to these childs } LoopNodes(od,og,nlist,dnodes); } else //if no childs { //add to split vector dnodes.push_back(nlist[i]); } } } This version of loop nodes works correctly for 2(or 1?) generations after - this will not divide neightbours nodes, only some corners. I need correct algorithm. Screenshot All I need - is correct version of LoopNodes, which can add all nodes for DivideNode.

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  • Using Recursive SQL and XML trick to PIVOT(OK, concat) a "Document Folder Structure Relationship" table, works like MySQL GROUP_CONCAT

    - by Kevin Shyr
    I'm in the process of building out a Data Warehouse and encountered this issue along the way.In the environment, there is a table that stores all the folders with the individual level.  For example, if a document is created here:{App Path}\Level 1\Level 2\Level 3\{document}, then the DocumentFolder table would look like this:IDID_ParentFolderName1NULLLevel 121Level 232Level 3To my understanding, the table was built so that:Each proposal can have multiple documents stored at various locationsDifferent users working on the proposal will have different access level to the folder; if one user is assigned access to a folder level, she/he can see all the sub folders and their content.Now we understand from an application point of view why this table was built this way.  But you can quickly see the pain this causes the report writer to show a document link on the report.  I wasn't surprised to find the report query had 5 self outer joins, which is at the mercy of nobody creating a document that is buried 6 levels deep, and not to mention the degradation in performance.With the help of 2 posts (at the end of this post), I was able to come up with this solution:Use recursive SQL to build out the folder pathUse SQL XML trick to concat the strings.Code (a reminder, I built this code in a stored procedure.  If you copy the syntax into a simple query window and execute, you'll get an incorrect syntax error) Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} -- Get all folders and group them by the original DocumentFolderID in PTSDocument table;WITH DocFoldersByDocFolderID(PTSDocumentFolderID_Original, PTSDocumentFolderID_Parent, sDocumentFolder, nLevel)AS (-- first member      SELECT 'PTSDocumentFolderID_Original' = d1.PTSDocumentFolderID            , PTSDocumentFolderID_Parent            , 'sDocumentFolder' = sName            , 'nLevel' = CONVERT(INT, 1000000)      FROM (SELECT DISTINCT PTSDocumentFolderID                  FROM dbo.PTSDocument_DY WITH(READPAST)            ) AS d1            INNER JOIN dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)                  ON d1.PTSDocumentFolderID = df1.PTSDocumentFolderID      UNION ALL      -- recursive      SELECT ddf1.PTSDocumentFolderID_Original            , df1.PTSDocumentFolderID_Parent            , 'sDocumentFolder' = df1.sName            , 'nLevel' = ddf1.nLevel - 1      FROM dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)            INNER JOIN DocFoldersByDocFolderID AS ddf1                  ON df1.PTSDocumentFolderID = ddf1.PTSDocumentFolderID_Parent)-- Flatten out folder path, DocFolderSingleByDocFolderID(PTSDocumentFolderID_Original, sDocumentFolder)AS (SELECT dfbdf.PTSDocumentFolderID_Original            , 'sDocumentFolder' = STUFF((SELECT '\' + sDocumentFolder                                         FROM DocFoldersByDocFolderID                                         WHERE (PTSDocumentFolderID_Original = dfbdf.PTSDocumentFolderID_Original)                                         ORDER BY PTSDocumentFolderID_Original, nLevel                                         FOR XML PATH ('')),1,1,'')      FROM DocFoldersByDocFolderID AS dfbdf      GROUP BY dfbdf.PTSDocumentFolderID_Original) And voila, I use the second CTE to join back to my original query (which is now a CTE for Source as we can now use MERGE to do INSERT and UPDATE at the same time).Each part of this solution would not solve the problem by itself because:If I don't use recursion, I cannot build out the path properly.  If I use the XML trick only, then I don't have the originating folder ID info that I need to link to the document.If I don't use the XML trick, then I don't have one row per document to show in the report.I could conceivably do this in the report function, but I'd rather not deal with the beginning or ending backslash and how to attach the document name.PIVOT doesn't do strings and UNPIVOT runs into the same problem as the above.I'm excited that each version of SQL server provides us new tools to solve old problems and/or enables us to solve problems in a more elegant wayThe 2 posts that helped me along:Recursive Queries Using Common Table ExpressionHow to use GROUP BY to concatenate strings in SQL server?

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  • Dig returns "status: REFUSED" for external queries?

    - by Mikey
    I can't seem to work out why my DNS isn't working properly, if I run dig from the nameserver it functions correctly: # dig ungl.org ; <<>> DiG 9.5.1-P2.1 <<>> ungl.org ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24585 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; QUESTION SECTION: ;ungl.org. IN A ;; ANSWER SECTION: ungl.org. 38400 IN A 188.165.34.72 ;; AUTHORITY SECTION: ungl.org. 38400 IN NS ns.kimsufi.com. ungl.org. 38400 IN NS r29901.ovh.net. ;; ADDITIONAL SECTION: ns.kimsufi.com. 85529 IN A 213.186.33.199 ;; Query time: 1 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Sat Mar 13 01:04:06 2010 ;; MSG SIZE rcvd: 114 but when I run it from another server in the same datacenter I receive: # dig @87.98.167.208 ungl.org ; <<>> DiG 9.5.1-P2.1 <<>> @87.98.167.208 ungl.org ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 18787 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;ungl.org. IN A ;; Query time: 1 msec ;; SERVER: 87.98.167.208#53(87.98.167.208) ;; WHEN: Sat Mar 13 01:01:35 2010 ;; MSG SIZE rcvd: 26 my zone file for this domain is $ttl 38400 ungl.org. IN SOA r29901.ovh.net. mikey.aol.com. ( 201003121 10800 3600 604800 38400 ) ungl.org. IN NS r29901.ovh.net. ungl.org. IN NS ns.kimsufi.com. ungl.org. IN A 188.165.34.72 localhost. IN A 127.0.0.1 www IN A 188.165.34.72 The server is running Ubuntu 9.10 and Bind 9, if anyone can shed some light on this for me it'd make me very happy! thanks

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  • How to block subreddits with BIND9?

    - by user1391189
    Please help me block NSFW subreddits like this one (http://www.reddit.com/r/NSFW/) I would like to keep access to SFW subreddits, but block certain subreddits that are distracting or NSFW. I know how to filter domains. (see files below) But how do I apply the filter only to certain subreddits? So far I have set up the following files: blocklist.conf zone "adimages.go.com" { type master; file "dummy-block"; }; zone "admonitor.net" { type master; file "dummy-block"; }; zone "ads.specificpop.com" { type master; file "dummy-block"; }; ... named.conf options { allow-query { 127.0.0.1; }; allow-recursion { 127.0.0.1; }; directory "c:\bind\etc"; notify no; }; zone "." IN { type hint; file "c:\bind\etc\named.root"; }; zone "localhost" IN { allow-update { none; }; file "c:\bind\etc\localhost.zone"; type master; }; zone "0.0.127.in-addr.arpa" IN { allow-update { none; }; file "c:\bind\etc\named.local"; type master; }; key "rndc-key" { algorithm hmac-md5; secret "O5VdbBKKEMzuLYjM60CxwuLLURFA6peDYHCBvZCqjoa6KtL1ggD7OTLeLtnu2jR5I5cwA/MQ8UdHc+9tMJRSiw=="; }; controls { inet 127.0.0.1 port 953 allow { 127.0.0.1; } keys { "rndc-key"; }; }; //Blocklist include "c:\bind\etc\blocklist.conf"; dummy-block $TTL 604800 @ IN SOA localhost. root.localhost. ( 2 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; @ IN NS localhost. @ IN A 127.0.0.1 * IN A 127.0.0.1

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  • Excessive CPU Utilization for Bind 9.8.1 `named` processes

    - by justinzane
    I just noticed that named is eating vast amounts of CPU time for a very small network with only a few domains. Can someone help me determine what is misconfigured, please? Or how to debug this. top top - 14:13:08 up 25 days, 14:16, 1 user, load average: 1.04, 1.04, 1.05 Tasks: 149 total, 1 running, 148 sleeping, 0 stopped, 0 zombie %Cpu(s): 17.3 us, 4.3 sy, 0.0 ni, 78.2 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 2042776 total, 1347916 used, 694860 free, 249396 buffers KiB Swap: 3976080 total, 30552 used, 3945528 free, 574164 cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 17445 bind 20 0 244m 42m 3124 S 99.4 2.2 2345:03 named rndc stats +++ Statistics Dump +++ (1352931389) ++ Incoming Requests ++ 65869 QUERY ++ Incoming Queries ++ 31809 A 241 NS 3 CNAME 27455 SOA 276 PTR 123 MX 462 TXT 5400 AAAA 7 A6 1 DS 14 DNSKEY 15 SPF 55 AXFR 8 ANY ++ Outgoing Queries ++ [View: internal] 22206 A 509 NS 10 SOA 25 PTR 12 MX 524 TXT 4851 AAAA 62 DNSKEY 19 SPF 3157 DLV [View: external] 87 A 2 NS 80 AAAA 120 DNSKEY 7 DLV [View: _bind] ++ Name Server Statistics ++ 65869 IPv4 requests received 27670 requests with EDNS(0) received 112 TCP requests received 65652 responses sent 20 truncated responses sent 27670 responses with EDNS(0) sent 62920 queries resulted in successful answer 37117 queries resulted in authoritative answer 28482 queries resulted in non authoritative answer 7 queries resulted in referral answer 591 queries resulted in nxrrset 53 queries resulted in SERVFAIL 2081 queries resulted in NXDOMAIN 14530 queries caused recursion 162 duplicate queries received 55 requested transfers completed ++ Zone Maintenance Statistics ++ 109536 IPv4 notifies sent ++ Resolver Statistics ++ [Common] [View: internal] 29362 IPv4 queries sent 2013 IPv6 queries sent 28531 IPv4 responses received 4209 NXDOMAIN received 6 SERVFAIL received 31 FORMERR received 32 EDNS(0) query failures 3359 query retries 836 query timeouts 5348 IPv4 NS address fetches 3271 IPv6 NS address fetches 83 IPv4 NS address fetch failed 2779 IPv6 NS address fetch failed 17421 DNSSEC validation attempted 12731 DNSSEC validation succeeded 4690 DNSSEC NX validation succeeded 21104 queries with RTT 10-100ms 7418 queries with RTT 100-500ms 3 queries with RTT 500-800ms 1 queries with RTT 800-1600ms [View: external] 192 IPv4 queries sent 104 IPv6 queries sent 192 IPv4 responses received 2 NXDOMAIN received 104 query retries 44 IPv4 NS address fetches 44 IPv6 NS address fetches 1 IPv4 NS address fetch failed 1 IPv6 NS address fetch failed 4 DNSSEC validation attempted 3 DNSSEC validation succeeded 1 DNSSEC NX validation succeeded 152 queries with RTT 10-100ms 40 queries with RTT 100-500ms [View: _bind] ++ Cache DB RRsets ++ [View: internal (Cache: internal)] 2007 A 652 NS 131 CNAME 1 MX 32 TXT 421 AAAA 28 DS 244 RRSIG 110 NSEC 3 DNSKEY 2 !A 2 !TXT 89 !AAAA 2 !SPF 14 !DLV 148 NXDOMAIN [View: external (Cache: external)] 55 A 12 NS 34 AAAA 2 DS 10 RRSIG 1 DNSKEY [View: _bind (Cache: _bind)] ++ Socket I/O Statistics ++ 82958 UDP/IPv4 sockets opened 2118 UDP/IPv6 sockets opened 4 TCP/IPv4 sockets opened 1 TCP/IPv6 sockets opened 82956 UDP/IPv4 sockets closed 2117 UDP/IPv6 sockets closed 58 TCP/IPv4 sockets closed 15 UDP/IPv4 socket bind failures 2117 UDP/IPv6 socket connect failures 29554 UDP/IPv4 connections established 59 TCP/IPv4 connections accepted 2117 UDP/IPv6 send errors 5 UDP/IPv4 recv errors ++ Per Zone Query Statistics ++ --- Statistics Dump --- (1352931389)

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  • FTP could not connect after applying local DNS(private DNS)

    - by Rahul
    I made a software router in CentOS linux and in that made a DNS server. I am using centOS 6..4 for making DNS i applied following steps: changed the host name = abc.zoom.com and domain name = zoom.com. then did changes in the named.rfc.1912 file as per rename named.localhost = forward and named.loopback = reverse in forward lookups i changed zone "zoom.com" IN { type master; file "forward"; allow-update { none; }; and in reverse lookups i changed zone "x.168.192.in-addr.arpa" IN { type master; file "reverse"; allow-update { none; }; and then did changes in the named.conf file options { listen-on port 53 {192.168.x.x;}; listen-on-v6 port 53 { ::1; }; directory "/var/named"; dump-file "/var/named/data/cache_dump.db"; statistics-file "/var/named/data/named_stats.txt"; memstatistics-file "/var/named/data/named_mem_stats.txt"; allow-query {any;}; recursion yes; 192.168.x.x is my local DNS address. then i copied lookups file in /var/named and edited the file "forward" $TTL 1D @ IN SOA abc.zoom.com. rahul.abc.zoom.com. ( 0 ; serial 1D ; refresh 1H ; retry 1W ; expire 3H ) ; minimum NS abc.zoom.com. abc A 192.168.x.x and for " reverse" $TTL 1D @ IN SOA abc.zoom.com. rahul.abc.zoom.com.( 0 ; serial 1D ; refresh 1H ; retry 1W ; expire 3H ) ; minimum NS abc.zoom.com. x PTR abc.zoom.com. when i put the public ip details in the Eth0 it was automatically redirect in to the resolve.conf when i checked through dig command the answer, query all were 1. my system is itself a Software router.In gateway of my all local machine i give my system ip address. however my DNS and Gateway IP is same. Now the problem is that. i gave the static ips to all my local machines when i give the DNS which i made i.e 192.168.x.x that time my ftp is not connect in filezilla software E.g: host : pqr.zoom.com ("zoom.com" is my local domain name) username : pqr password : pqr gives an error: Error: Connection timed out Error: Could not connect to server but if i give the public DNS address it get connected. i want to solve this problem please give solution on this.

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  • BIND DNS server (Windows) - Unable to access my local domain from other computers on LAN

    - by Ricardo Saraiva
    I have a BIND DNS server running on my Windows 7 development machine and I'm serving pages with WAMPSERVER. My ideia is to develop some tools (in PHP) for my intranet at work and I want them to be accessible via LAN in this format: http://tools.mycompany.com I've already placed BIND and I can access http://tools.mycompany.com on the machine that holds BIND server, but I cannot access it from other LAN computers. I've done the following on my router: defined static IP's for all LAN computers set Port Forwarding to my server (remember: it serves DNS and Web pages) set DNS server configuration to point to my LAN server On LAN computers, I went to Local Area Network properties and also changed the DNS server IP in order to point to my local DNS server. If it helps, here is my named.conf file: options { directory "c:\windows\SysWOW64\dns\etc"; forwarders {127.0.0.1; 8.8.8.8; 8.8.4.4;}; pid-file "run\named.pid"; allow-transfer { none; }; recursion no; }; logging{ channel my_log{ file "log\named.log" versions 3 size 2m; severity info; print-time yes; print-severity yes; print-category yes; }; category default{ my_log; }; }; zone "mycompany.com" IN { type master; file "zones\db.mycompany.com.txt"; allow-transfer { none; }; }; key "rndc-key" { algorithm hmac-md5; secret "qfApxn0NxXiaacFHpI86Rg=="; }; controls { inet 127.0.0.1 port 953 allow { 127.0.0.1; } keys { "rndc-key"; }; }; ...and a single zone I've defined - file db.mycompany.com.txt: $TTL 6h @ IN SOA tools.mycompany.com. hostmaster.mycompany.com. ( 2014042601 10800 3600 604800 86400 ) @ NS tools.mycompany.com. tools IN A 192.168.1.4 www IN A 192.168.1.4 On the file above 192.168.1.4 is the IP of the local machine inside my LAN. Can someone help me here? I need my web pages to be accessible from other computers inside my LAN using my custom domain name. I've tried on other computers and they can access my server via http://192.168.1.4/, but no able when using http://tools.mycompany.com . Please, consider the following: I'm completely new to BIND I have basic knowledge in Apache configuration Thanks a lot for your help.

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  • NFS4 / ZFS: revert ACL to clean/inherited state

    - by Keiichi
    My problem is identical to this Windows question, but pertains NFS4 (Linux) and the underlying ZFS (OpenIndiana) we are using. We have this ZFS shared via NFS4 and CIFS for Linux and Windows users respectively. It would be nice for both user groups to benefit from ACLs, but the one missing puzzle piece goes thusly: Each user has a home, where he sets a top-level, inherited ACL. He can later on refine permissions for the contained files/folders iteratively. Over time, sometimes permissions need to be generalized again to avoid increasing pollution of ACL entries. You can tweak the ACL of every single file if need be to obtain the wanted permissions, but that defeats the purpose of inherited ACLs. So, how can an ACL be completely cleared like in the question linked above? I have found nothing about what a blank, inherited ACL should look like. This usecase simply does not seem to exist. In fact, the solaris chmod manpage clearly states A- Removes all ACEs for current ACL on file and replaces current ACL with new ACL that represents only the current mode of the file. I.e. we get three new ACL entries filled with stuff representing the permission bits, which is rather useless for cleaning up. If I try to manually remove every ACE, on the last one I get chmod A0- <file> chmod: ERROR: Can't remove all ACL entries from a file Which by the way makes me think: and why not? In fact, I really want the whole file-specific ACL gone. The same holds for linux, which enumerates ACEs starting with 1(!), and verbalizes its woes less diligently nfs4_setacl -x 1 <file> Failed setxattr operation: Unknown error 524 So, what is the idea behind ACLs under Solaris/NFS? Can they never be cleaned up? Why does the recursion option for the ACL setting commands pollute all children instead of setting a single ACL and making the children inherit? Is this really the intention of the designers? I can clean up the ACLs using a windows client perfectly well, but am I supposed to tell the linux users they have to switch OS just to consolidate permissions?

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  • Caching issue with Centos forwarding DNS server

    - by Paddington
    I installed a Forwarding DNS server on Centos 5.10 and it is resolving addresses e.g google.com. When I stopped named (service named stop) and tried to dig (dig @localhost A google.com) there was a failure to resolve the address. I checked and see the caching daemon nscd is running. Does this mean the server is not caching at all? How can I get it to cache? named.conf options { // Those options should be used carefully because they disable port // randomization // query-source port 53; // query-source-v6 port 53; // Put files that named is allowed to write in the data/ directory: listen-on port 53 {127.0.0.1; 10.0.0.4;}; directory "/var/named"; // the default dump-file "/var/named/chroot/var/named/data/cache_dump.db"; statistics-file "/var/named/chroot/var/named/data/named_stats.txt"; memstatistics-file "/var/named/chroot/var/named/data/named_mem_stats.txt"; // allow-query {localhost; 192.168.0.0/24; 10.0.0.0/8;}; recursion yes; //allow-query { localhost; 10.0.0.0/8;}; allow-query { localhost; any; }; allow-query-cache { localhost; any; }; forward only; forwarders {8.8.8.8; 8.8.4.4;}; dnssec-enable yes; // dnssec-lookaside auto; /* Path to ISC DLV key */ // bindkeys-file "/etc/named.iscdlv.key"; // managed-keys-directory "/var/named/dynamic"; }; logging { channel default_debug { file "data/named.run"; severity dynamic; }; }; **

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  • Formal Languages, Inductive Proofs &amp; Regular Expressions

    - by MarkPearl
    So I am slogging away at my UNISA stuff. I have just finished doing the initial once non stop read through the first 11 chapters of my COS 201 Textbook - “Introduction to Computer Theory 2nd Edition” by Daniel Cohen. It has been an interesting couple of days, with familiar concepts coming up as well as some new territory. In this posting I am going to cover the first couple of chapters of the book. Let start with Formal Languages… What exactly is a formal language? Pretty much a no duh question for me but still a good one to ask – a formal language is a language that is defined in a precise mathematical way. Does that mean that the English language is a formal language? I would say no – and my main motivation for this is that one can have an English sentence that is correct grammatically that is also ambiguous. For example the ambiguous sentence: "I once shot an elephant in my pyjamas.” For this and possibly many other reasons that I am unaware of, English is termed a “Natural Language”. So why the importance of formal languages in computer science? Again a no duh question in my mind… If we want computers to be effective and useful tools then we need them to be able to evaluate a series of commands in some form of language that when interpreted by the device no confusion will exist as to what we were requesting. Imagine the mayhem that would exist if a computer misinterpreted a command to print a document and instead decided to delete it. So what is a Formal Language made up of… For my study purposes a language is made up of a finite alphabet. For a formal language to exist there needs to be a specification on the language that will describe whether a string of characters has membership in the language or not. There are two basic ways to do this: By a “machine” that will recognize strings of the language (e.g. Finite Automata). By a rule that describes how strings of a language can be formed (e.g. Regular Expressions). When we use the phrase “string of characters”, we can also be referring to a “word”. What is an Inductive Proof? So I am not to far into my textbook and of course it starts referring to proofs and different types. I have had to go through several different approaches of proofs in the past, but I can never remember their formal names , so when I saw “inductive proof” I thought to myself – what the heck is that? Google to the rescue… An inductive proof is like a normal proof but it employs a neat trick which allows you to prove a statement about an arbitrary number n by first proving it is true when n is 1 and then assuming it is true for n=k and showing it is true for n=k+1. The idea is that if you want to show that someone can climb to the nth floor of a fire escape, you need only show that you can climb the ladder up to the fire escape (n=1) and then show that you know how to climb the stairs from any level of the fire escape (n=k) to the next level (n=k+1). Does this sound like a form of recursion? No surprise then that in the same chapter they deal with recursive definitions. An example of a recursive definition for the language EVEN would the 3 rules below: 2 is in EVEN If x is in EVEN then so is x+2 The only elements in the set EVEN are those that be produced by the rules above. Nothing to exciting… So if a definition for a language is done recursively, then it makes sense that the language can be proved using induction. Regular Expressions So I am wondering to myself what use is this all – in fact – I find this the biggest challenge to any university material is that it is quite hard to find the immediate practical applications of some theory in real life stuff. How great was my joy when I suddenly saw the word regular expression being introduced. I had been introduced to regular expressions on Stack Overflow where I was trying to recognize if some text measurement put in by a user was in a valid form or not. For instance, the imperial system of measurement where you have feet and inches can be represented in so many different ways. I had eventually turned to regular expressions as an easy way to check if my parser could correctly parse the text or not and convert it to a normalize measurement. So some rules about languages and regular expressions… Any finite language can be represented by at least one if not more regular expressions A regular expressions is almost a rule syntax for expressing how regular languages can be formed regular expressions are cool For a regular expression to be valid for a language it must be able to generate all the words in the language and no other words. This is important. It doesn’t help me if my regular expression parses 100% of my measurement texts but also lets one or two invalid texts to pass as well. Okay, so this posting jumps around a bit – but introduces some very basic fundamentals for the subject which will be built on in later postings… Time to go and do some practical examples now…

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  • yield – Just yet another sexy c# keyword?

    - by George Mamaladze
    yield (see NSDN c# reference) operator came I guess with .NET 2.0 and I my feeling is that it’s not as wide used as it could (or should) be.   I am not going to talk here about necessarity and advantages of using iterator pattern when accessing custom sequences (just google it).   Let’s look at it from the clean code point of view. Let's see if it really helps us to keep our code understandable, reusable and testable.   Let’s say we want to iterate a tree and do something with it’s nodes, for instance calculate a sum of their values. So the most elegant way would be to build a recursive method performing a classic depth traversal returning the sum.           private int CalculateTreeSum(Node top)         {             int sumOfChildNodes = 0;             foreach (Node childNode in top.ChildNodes)             {                 sumOfChildNodes += CalculateTreeSum(childNode);             }             return top.Value + sumOfChildNodes;         }     “Do One Thing” Nevertheless it violates one of the most important rules “Do One Thing”. Our  method CalculateTreeSum does two things at the same time. It travels inside the tree and performs some computation – in this case calculates sum. Doing two things in one method is definitely a bad thing because of several reasons: ·          Understandability: Readability / refactoring ·          Reuseability: when overriding - no chance to override computation without copying iteration code and vice versa. ·          Testability: you are not able to test computation without constructing the tree and you are not able to test correctness of tree iteration.   I want to spend some more words on this last issue. How do you test the method CalculateTreeSum when it contains two in one: computation & iteration? The only chance is to construct a test tree and assert the result of the method call, in our case the sum against our expectation. And if the test fails you do not know wether was the computation algorithm wrong or was that the iteration? At the end to top it all off I tell you: according to Murphy’s Law the iteration will have a bug as well as the calculation. Both bugs in a combination will cause the sum to be accidentally exactly the same you expect and the test will PASS. J   Ok let’s use yield! That’s why it is generally a very good idea not to mix but isolate “things”. Ok let’s use yield!           private int CalculateTreeSumClean(Node top)         {             IEnumerable<Node> treeNodes = GetTreeNodes(top);             return CalculateSum(treeNodes);         }             private int CalculateSum(IEnumerable<Node> nodes)         {             int sumOfNodes = 0;             foreach (Node node in nodes)             {                 sumOfNodes += node.Value;             }             return sumOfNodes;         }           private IEnumerable<Node> GetTreeNodes(Node top)         {             yield return top;             foreach (Node childNode in top.ChildNodes)             {                 foreach (Node currentNode in GetTreeNodes(childNode))                 {                     yield return currentNode;                 }             }         }   Two methods does not know anything about each other. One contains calculation logic another jut the iteration logic. You can relpace the tree iteration algorithm from depth traversal to breath trevaersal or use stack or visitor pattern instead of recursion. This will not influence your calculation logic. And vice versa you can relace the sum with product or do whatever you want with node values, the calculateion algorithm is not aware of beeng working on some tree or graph.  How about not using yield? Now let’s ask the question – what if we do not have yield operator? The brief look at the generated code gives us an answer. The compiler generates a 150 lines long class to implement the iteration logic.       [CompilerGenerated]     private sealed class <GetTreeNodes>d__0 : IEnumerable<Node>, IEnumerable, IEnumerator<Node>, IEnumerator, IDisposable     {         ...        150 Lines of generated code        ...     }   Often we compromise code readability, cleanness, testability, etc. – to reduce number of classes, code lines, keystrokes and mouse clicks. This is the human nature - we are lazy. Knowing and using such a sexy construct like yield, allows us to be lazy, write very few lines of code and at the same time stay clean and do one thing in a method. That's why I generally welcome using staff like that.   Note: The above used recursive depth traversal algorithm is possibly the compact one but not the best one from the performance and memory utilization point of view. It was taken to emphasize on other primary aspects of this post.

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  • Google Streetview under V3 Code having hiccups and delays

    - by jeffkee
    http://new.brocksmeaton.com/showlisting.php/196/-7210-Arbutus-Place-Whytecliff-West-Vancouver-west-vancouver-real-estate The really odd thing is I had this working yesterday and today it's not working. I'm using jQuery UI to switch the tabs on the location map/street view module. I've recently upgraded the Google Maps code as well as the Google Streetview code to version 3. So when I open it in Firefox, with Firebug on, as soon as I switch to the Streetview tab, the navigation and zoom in out controls show, but nothing shows.. and then when I try to drag the map around, it does not move around, but instead, causes errors in Firebug: "too much recursion". So it causes the whole browser to become buggy, slows down, and the errors happen, and nothing shows on the streetview pane. Most of the map loading code is located in inline Javascript on the page itself. Some of the code is under showlisting.js <script type="text/javascript" src="/js/showlisting.js"></script> <script type="text/javascript"> // Call this function when the page has been loaded function loadmap() { var latlng = new google.maps.LatLng(49.374918567425475, -123.28996885871596); var myOptions = { zoom: 14, center: latlng, mapTypeId: google.maps.MapTypeId.ROADMAP }; var map = new google.maps.Map(document.getElementById('listingmap'), myOptions); var listingicon = '/images/activehouse.png'; var infowindow = new google.maps.InfoWindow(); homemarker = new google.maps.Marker({position: latlng, map: map, icon: listingicon}); google.maps.event.addListener(homemarker, 'click', function() { infowindow.setContent('<div style="height:80px; width:250px; color:#333;"><p>7210 Arbutus Place<br />Whytecliff, West Vancouver</div>') infowindow.open(map,homemarker); }); } function loadpano() { var latlng = new google.maps.LatLng(49.374918567425475, -123.28996885871596); $('#listingpanorama').slideDown(500, function() { var panoramaOptions = { addressControl:false, position: latlng, pov: { heading: 34, pitch: 30, zoom: 1 } }; var panorama = new google.maps.StreetViewPanorama(document.getElementById('listingpanorama'), panoramaOptions); }); return false; } </script> My old one under GOogle API Version 2 is here FYI if you want to take a look at it: http://demo.brixwork.com/master/showlisting.php/63/1701-388-Drake-Street-False-Creek-North-Vancouver-

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  • Python - calculate multinomial probability density functions on large dataset?

    - by Seafoid
    Hi, I originally intended to use MATLAB to tackle this problem but the inbuilt functions has limitations that do not suit my goal. The same limitation occurs in NumPy. I have two tab-delimited files. The first is a file showing amino acid residue, frequency and count for an in-house database of protein structures, i.e. A 0.25 1 S 0.25 1 T 0.25 1 P 0.25 1 The second file consists of quadruplets of amino acids and the number of times they occur, i.e. ASTP 1 Note, there are 8,000 such quadruplets. Based on the background frequency of occurence of each amino acid and the count of quadruplets, I aim to calculate the multinomial probability density function for each quadruplet and subsequently use it as the expected value in a maximum likelihood calculation. The multinomial distribution is as follows: f(x|n, p) = n!/(x1!*x2!*...*xk!)*((p1^x1)*(p2^x2)*...*(pk^xk)) where x is the number of each of k outcomes in n trials with fixed probabilities p. n is 4 four in all cases in my calculation. I have created three functions to calculate this distribution. # functions for multinomial distribution def expected_quadruplets(x, y): expected = x*y return expected # calculates the probabilities of occurence raised to the number of occurrences def prod_prob(p1, a, p2, b, p3, c, p4, d): prob_prod = (pow(p1, a))*(pow(p2, b))*(pow(p3, c))*(pow(p4, d)) return prob_prod # factorial() and multinomial_coefficient() work in tandem to calculate C, the multinomial coefficient def factorial(n): if n <= 1: return 1 return n*factorial(n-1) def multinomial_coefficient(a, b, c, d): n = 24.0 multi_coeff = (n/(factorial(a) * factorial(b) * factorial(c) * factorial(d))) return multi_coeff The problem is how best to structure the data in order to tackle the calculation most efficiently, in a manner that I can read (you guys write some cryptic code :-)) and that will not create an overflow or runtime error. To data my data is represented as nested lists. amino_acids = [['A', '0.25', '1'], ['S', '0.25', '1'], ['T', '0.25', '1'], ['P', '0.25', '1']] quadruplets = [['ASTP', '1']] I initially intended calling these functions within a nested for loop but this resulted in runtime errors or overfloe errors. I know that I can reset the recursion limit but I would rather do this more elegantly. I had the following: for i in quadruplets: quad = i[0].split(' ') for j in amino_acids: for k in quadruplets: for v in k: if j[0] == v: multinomial_coefficient(int(j[2]), int(j[2]), int(j[2]), int(j[2])) I haven'te really gotten to how to incorporate the other functions yet. I think that my current nested list arrangement is sub optimal. I wish to compare the each letter within the string 'ASTP' with the first component of each sub list in amino_acids. Where a match exists, I wish to pass the appropriate numeric values to the functions using indices. Is their a better way? Can I append the appropriate numbers for each amino acid and quadruplet to a temporary data structure within a loop, pass this to the functions and clear it for the next iteration? Thanks, S :-)

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  • How to dynamically expand a string in C

    - by sa125
    Hi - I have a function that recursively makes some calculations on a set of numbers. I want to also pretty-print the calculation in each recursion call by passing the string from the previous calculation and concatenating it with the current operation. A sample output might look like this: 3 (3) + 2 ((3) + 2) / 4 (((3) + 2) / 4) x 5 ((((3) + 2) / 4) x 5) + 14 ... and so on So basically, the second call gets 3 and appends + 2 to it, the third call gets passed (3) + 2 , etc. My recursive function prototype looks like this: void calc_rec(int input[], int length, char * previous_string); I wrote a 2 helper functions to help me with the operation, but they implode when I test them: /********************************************************************** * dynamically allocate and append new string to old string and return a pointer to it **********************************************************************/ char * strapp(char * old, char * new) { // find the size of the string to allocate int len = sizeof(char) * (strlen(old) + strlen(new)); // allocate a pointer to the new string char * out = (char*)malloc(len); // concat both strings and return sprintf(out, "%s%s", old, new); return out; } /********************************************************************** * returns a pretty math representation of the calculation op **********************************************************************/ char * mathop(char * old, char operand, int num) { char * output, *newout; char fstr[50]; // random guess.. couldn't think of a better way. sprintf(fstr, " %c %d", operand, num); output = strapp(old, fstr); newout = (char*)malloc( 2*sizeof(char)+sizeof(output) ); sprintf(newout, "(%s)", output); free(output); return newout; } void test_mathop() { int i, total = 10; char * first = "3"; printf("in test_mathop\n"); while (i < total) { first = mathop(first, "+", i); printf("%s\n", first); ++i; } } strapp() returns a pointer to newly appended strings (works), and mathop() is supposed to take the old calculation string ("(3)+2"), a char operand ('+', '-', etc) and an int, and return a pointer to the new string, for example "((3)+2)/3". Any idea where I'm messing things up? thanks.

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