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  • Level-order in Haskell

    - by brain_damage
    I have a structure for a tree and I want to print the tree by levels. data Tree a = Nd a [Tree a] deriving Show type Nd = String tree = Nd "a" [Nd "b" [Nd "c" [], Nd "g" [Nd "h" [], Nd "i" [], Nd "j" [], Nd "k" []]], Nd "d" [Nd "f" []], Nd "e" [Nd "l" [Nd "n" [Nd "o" []]], Nd "m" []]] preorder (Nd x ts) = x : concatMap preorder ts postorder (Nd x ts) = (concatMap postorder ts) ++ [x] But how to do it by levels? "levels tree" should print ["a", "bde", "cgflm", "hijkn", "o"]. I think that "iterate" would be suitable function for the purpose, but I cannot come up with a solution how to use it. Would you help me, please?

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  • Design suggestion for expression tree evaluation with time-series data

    - by Lirik
    I have a (C#) genetic program that uses financial time-series data and it's currently working but I want to re-design the architecture to be more robust. My main goals are: sequentially present the time-series data to the expression trees. allow expression trees to access previous data rows when needed. to optimize performance of the data access while evaluating the expression trees. keep a common interface so various types of data can be used. Here are the possible approaches I've thought about: I can evaluate the expression tree by passing in a data row into the root node and let each child node use the same data row. I can evaluate the expression tree by passing in the data row index and letting each node get the data row from a shared DataSet (currently I'm passing the row index and going to multiple synchronized arrays to get the data). Hybrid: an immutable data set is accessible by all of the expression trees and each expression tree is evaluated by passing in a data row. The benefit of the first approach is that the data row is being passed into the expression tree and there is no further query done on the data set (which should increase performance in a multithreaded environment). The drawback is that the expression tree does not have access to the rest of the data (in case some of the functions need to do calculations using previous data rows). The benefit of the second approach is that the expression trees can access any data up to the latest data row, but unless I specify what that row is, I'll have to iterate through the rows and figure out which one is the last one. The benefit of the hybrid is that it should generally perform better and still provide access to the earlier data. It supports two basic "views" of data: the latest row and the previous rows. Do you guys know of any design patterns or do you have any tips that can help me build this type of system? Should I use a DataSet to hold and present the data, or are there more efficient ways to present rows of data while maintaining a simple interface? FYI: All of my code is written in C#.

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  • Asp.Net tree view in SharePoint webpart- Input string error

    - by Faiz
    Hi All, I am facing a very strange issue. I have a SharePoint webpart that displays an asp.net tree view. It takes tree depth from a drop down. To improve performance of the tree view, i am setting the PopulateOnDemand property to true for the last level of the tree depth. For example, if i have a total of 10 levels in the data and the user selects tree depth as 3, then the third level data i set PopulateOnDemand to true. Now comes the strange part. When i click on the + image on the third level, and if there are children under that particular node then call back happens and node gets expanded. But if there no children for that particular node, then click + throws "Input string was not in the correct format" error. I have made sure that there is no server side error. Some things looks to be fishy when internet explorer is trying to bind construct the expanded node. Please let me know if any one faced similar issue or the resolution for the same? Thanks in advance

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  • Example of tree.drop_mode with jQuery sortable anywhere

    - by fred
    Hello Everyone, I have a working tree of galleries next to a sortable list of image thumbnails. I've been vainly trying to set up the galleries tree so that users can add images to the galleries by dropping the sortable thumbnails on to the galleries tree. I've been told this requires drop_mode. All efforts to get it to work have failed and I can't really make heads or tails of the drop_mode documentation. I've sought out some working examples via Google of just such an application but have failed. Can anyone point me to a working example of either a draggable or sortable list that successfully drops on to a tree and passes along some parameters between the two? Thanks!

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  • Adding UIComponent to both Canvas and Tree in Flex 3

    - by Chris M
    I currently am trying to add a custom class which subclasses UIComponent to both a tree and a canvas, but when I try to re-order the tree by dragging I get this error: TypeError: Error #1010: A term is undefined and has no properties. at mx.controls::Tree/get firstVisibleItem()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\controls\Tree.as:764] at flash.utils::ByteArray/writeObject() at flash.desktop::Clipboard/putSerialization() at flash.desktop::Clipboard/convertFlashFormat() at flash.desktop::Clipboard/setData() at mx.managers::NativeDragManagerImpl/doDrag()[C:\autobuild\3.2.0\frameworks\projects\airframework\src\mx\managers\NativeDragManagerImpl.as:282] at mx.managers::DragManager$/doDrag()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\managers\DragManager.as:243] at mx.controls.listClasses::ListBase/dragStartHandler()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\controls\listClasses\ListBase.as:9085] at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\UIComponent.as:9298] at mx.controls.listClasses::ListBase/mouseMoveHandler()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\controls\listClasses\ListBase.as:8822] When I do not add the UIComponent to the canvas, this error does not occur, anyone have any knowledge as to why this happens?

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  • Depth First Search Basics

    - by cam
    I'm trying to improve my current algorithm for the 8 Queens problem, and this is the first time I'm really dealing with algorithm design/algorithms. I want to implement a depth-first search combined with a permutation of the different Y values described here: http://en.wikipedia.org/wiki/Eight_queens_puzzle#The_eight_queens_puzzle_as_an_exercise_in_algorithm_design I've implemented the permutation part to solve the problem, but I'm having a little trouble wrapping my mind around the depth-first search. It is described as a way of traversing a tree/graph, but does it generate the tree graph? It seems the only way that this method would be more efficient only if the depth-first search generates the tree structure to be traversed, by implementing some logic to only generate certain parts of the tree. So essentially, I would have to create an algorithm that generated a pruned tree of lexigraphic permutations. I know how to implement the pruning logic, but I'm just not sure how to tie it in with the permutation generator since I've been using next_permutation. Is there any resources that could help me with the basics of depth first searches or creating lexigraphic permutations in tree form?

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  • sql statement to Expression tree

    - by Joo Park
    I'm wondering how one would translate a sql string to an expression tree. Currently, in Linq to SQL, the expression tree is translated to a sql statement. How does on go the other way? How would you translate select * from books where bookname like '%The%' and year > 2008 into an expression tree in c#?

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  • Any tips of how to handle hierarchical trees in relational model?

    - by George
    Hello all. I have a tree structure that can be n-levels deep, without restriction. That means that each node can have another n nodes. What is the best way to retrieve a tree like that without issuing thousands of queries to the database? I looked at a few other models, like flat table model, Preorder Tree Traversal Algorithm, and so. Do you guys have any tips or suggestions of how to implement a efficient tree model? My objective in the real end is to have one or two queries that would spit the whole tree for me. With enough processing i can display the tree in dot net, but that would be in client machine, so, not much of a big deal. Thanks for the attention

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  • Eclipse RCP Preferences Dialog Tree Size

    - by nerduban
    In my RCP application, I'm trying to use the Eclipse preferences dialog. I'm adding extensions to the "org.eclipse.ui.preferencePages" and preparing related IWorkbenchPreferencePage implementations. My preference page names are a bit long, so that they are not totally visible on the left side tree of the preferences dialog. Dragging the sash bar to the right increases the width of this tree, but it is resetted after the program is closed and reopened. Is it possible to increase the default width of this tree?

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  • Hierarchy inheritance

    - by reito
    I had faced the problem. In my C++ hierarchy tree I have two branches for entities of difference nature, but same behavior - same interface. I created such hierarchy trees (first in image below). And now I want to work with Item or Base classes independetly of their nature (first or second). Then I create one abstract branch for this use. My mind build (second in image below). But it not working. Working scheme seems (third in image below). It's bad logic, I think... Do anybody have some ideas about such hierarchy inheritance? How make it more logical? More simple for understanding? Image Sorry for my english - russian internet didn't help:) Update: You ask me to be more explicit, and I will be. In my project (plugins for Adobe Framemaker) I need to work with dialogs and GUI controls. In some places I working with WinAPI controls, and some other places with FDK (internal Framemaker) controls, but I want to work throw same interface. I can't use one base class and inherite others from it, because all needed controls - is a hierarchy tree (not one class). So I have one hierarchy tree for WinAPI controls, one for FDK and one abstract tree to use anyone control. For example, there is an Edit control (WinEdit and FdkEdit realization), a Button control (WinButton and FdkButton realization) and base entity - Control (WinControl and FdkControl realization). For now I can link my classes in realization trees (Win and Fdk) with inheritence between each of them (WinControl is base class for WinButton and WinEdit; FdkControl is base class for FdkButton and FdkEdit). And I can link to abstract classes (Control is base class for WinControl and FdkControl; Edit is base class for WinEdit and FdkEdit; Button is base class for WinButton and FdkButton). But I can't link my abstract tree - compiler swears. In fact I have two hierarchy trees, that I want to inherite from another one. Update: I have done this quest! :) I used the virtual inheritence and get such scheme (http://img12.imageshack.us/img12/7782/99614779.png). Abstract tree has only absolute abstract methods. All inheritence in abstract tree are virtual. Link from realization tree to abstract are virtual. On image shown only one realization tree for simplicity. Thanks for help!

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  • Any tips of how to handle hierarchial trees in relational model?

    - by George
    Hello all. I have a tree structure that can be n-levels deep, without restriction. That means that each node can have another n nodes. What is the best way to retrieve a tree like that without issuing thousands of queries to the database? I looked at a few other models, like flat table model, Preorder Tree Traversal Algorithm, and so. Do you guys have any tips or suggestions of how to implement a efficient tree model? My objective in the real end is to have one or two queries that would spit the whole tree for me. With enough processing i can display the tree in dot net, but that would be in client machine, so, not much of a big deal. Thanks for the attention

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  • [Ext.tree.TreePanel] getNodeById does not work

    - by Moon
    Hi, I have a ext treepanel with json. var tree = new Ext.tree.TreePanel({ renderTo:'tree-container', title: 'Category', height: 300, width: 400, useArrows:true, autoScroll:true, animate:true, enableDD:true, containerScroll: true, rootVisible: false, frame: true, root: { text: 'Category', draggable: false, id: '0' }, // auto create TreeLoader dataUrl: $("#web").val() + "/category/index/get-nodes", listeners: { 'checkchange': function(node, checked){ if(checked){ categoryManager.add(node.id); //node.getUI().addClass('complete'); }else{ categoryManager.remove(node.id); // node.getUI().removeClass('complete'); } } } }); dataUrl loads the following json code [{"text":"Code Snippet","id":"1","cls":"folder","checked":false,"children":[{"text":"PHP","id":"3","cls":"file","checked":false,"children":[]},{"text":"Javascript","id":"4","cls":"file","checked":false,"children":[]}]}] when I try to find a node by console.log( tree.getNodeByid(3) ), it shows that it is undefined. Do I have a problem with my code?

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  • Git: Find duplicate blobs (files) in this tree

    - by Readonly
    This is sort of a follow-up to this question. If there are multiple blobs with the same contents, they are only stored once in the git repository because their SHA-1's will be identical. How would one go about finding all duplicate files for a given tree? Would you have to walk the tree and look for duplicate hashes, or does git provide backlinks from each blob to all files in a tree that reference it?

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  • A question on getting number of nodes in a Binary Tree

    - by Robert
    Dear all, I have written up two functions (pseudo code) for calculation the number of nodes and the tree height of a Binary Tree,given the root of the tree. Most importantly,the Binary Tree is represented as the First chiled/next sibling format. so struct TreeNode { Object element; TreeNode *firstChild; TreeNode *nextSibling; } Calculate the # of nodes: public int countNode(TreeNode root) { int count=0; while(root!=null) { root= root.firstChild; count++; } return count; } public int countHeight(TreeNode root) { int height=0; while(root!=null) { root= root.nextSibling; height++; } return height; } This is one of the problem I saw on an algorithm book,and my solution above seems to have some problems,also I didn't quite get the points of using this First Child/right sibling representation of Binary Tree,could you guys give me some idea and feedback,please? Cheers!

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  • Haskell Binary Tree Function (map)

    - by Bizarro
    How can i define a Haskell function which will apply a function to every value in a binary tree? So i know that it is similar to the map function - and that its type would be: mapT :: (a - b) - Tree a - Tree b but thats about it...

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  • Rails - how to serialize a tree not in a form

    - by tiny_clanger
    I started with the standard scriptaculous drag and drop tree, and that all works fine. Then started implementing this: http://www.artweb-design.de/2008/5/30/scriptaculous-sortabletree which gives a good drag and drop tree Where I am stuck is how to get serialize the tree (unordered list)? It's not in a form, and I can't find a way to serialize it to move onto setting up the AJAX update.

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  • jquery ajaxSubmit jquery file tree

    Hi, I'm using a jquery file tree and I'd like to allow users to upload files to whatever directory they're currently in. I am having an issue binding the form within the tree, though, since the tree is loading dynamically and obviously can't bind a form that doesn't exist. Any ideas would be greatly appreciated!

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  • GWT: Editing Text Of Tree Item

    - by kirtcathey
    Hi All. When a user clicks a 'Add Node' button above a tree and the program adds a tree item below the selected node, I would like to insert the new tree item with the text highlight and ready for editing by the user... like labels in GMail. Any ideas? --Kirt

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  • Why are trees shining in background?

    - by Kinected
    Currently I am creating a forest scene in the dark, and the trees are shining far away, but when I get close they are fine. I have the shaders set to "Nature/Tree Soft Occlusion [bark/leaves]", but they are still rendering strange far away, but close they are fine. I tried placing the trees in a folder named "Ambient-Occlusion" like said here, but no luck. Also fog is turned off. Thanks in advance.

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  • Only three primary partitions?

    - by ctype.h
    As everyone probably knows, Windows allows a drive to have four primary partitions, one of which may be active. However, I have only three primary partitions. I shrunk one and created a fourth partition so I could install Windows 8 on it, but Disk Management only allows it to be a logical partition. Why might this be the case? If I cannot convert it to a primary partition, is it advisable to install Windows on a logical partition? If so, is hibernation supported?

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