Search Results

Search found 4232 results on 170 pages for 'tree traversal'.

Page 23/170 | < Previous Page | 19 20 21 22 23 24 25 26 27 28 29 30  | Next Page >

  • Confused about definition of a 'median' when constructing a kd-Tree

    - by user352636
    Hi there. Im trying to build a kd-tree for searching through a set of points, but am getting confused about the use of 'median' in the wikipedia article. For ease of use, the wikipedia article states the pseudo-code of kd-tree construction as: function kdtree (list of points pointList, int depth) { if pointList is empty return nil; else { // Select axis based on depth so that axis cycles through all valid values var int axis := depth mod k; // Sort point list and choose median as pivot element select median by axis from pointList; // Create node and construct subtrees var tree_node node; node.location := median; node.leftChild := kdtree(points in pointList before median, depth+1); node.rightChild := kdtree(points in pointList after median, depth+1); return node; } } I'm getting confused about the "select median..." line, simply because I'm not quite sure what is the 'right' way to apply a median here. As far as I know, the median of an odd-sized (sorted) list of numbers is the middle element (aka, for a list of 5 things, element number 3, or index 2 in a standard zero-based array), and the median of an even-sized array is the sum of the two 'middle' elements divided by two (aka, for a list of 6 things, the median is the sum of elements 3 and 4 - or 2 and 3, if zero-indexed - divided by 2.). However, surely that definition does not work here as we are working with a distinct set of points? How then does one choose the correct median for an even-sized list of numbers, especially for a length 2 list? I appreciate any and all help, thanks! -Stephen

    Read the article

  • Hide the last children of an XML data provider (not to be displayed in mx:Tree)

    - by Andree
    Hi there! I have an hierachical XML data, and I want to display it as a tree. The XML data is something like this: <services> <service name="TestService" endpoint=""> <method name="sayHi"> <parameter name="firstName" /> <parameter name="lastName" /> </method> <method name="sayGoodbye"> <parameter name="firstName" /> <parameter name="lastName" /> </method> </service> <service name="AnotherTestService"> <method name="getName" /> <method name="setName"> <parameter name="name" /> </method> </service> </services> However, I don't want to display the last elements (parameters) in the tree because, well, it is not meant to be displayed, but still it has to be there. Any advice on how can I achieve that? I am thinking of either extending DefaultDataDescriptor or create a class which implement ITreeDataDescriptor. Which approach will be suitable in this case?

    Read the article

  • problem in creating a php tree menu

    - by Mac Taylor
    hi mates im writing a tree menu for my categories in php and i wonder how can i code it correctly ! this is my table in database " |----topicid------topicname--------parent | |---- 1 ------ News -------- 0 | |---- 2 ------ sport -------- 1 | |---- 3 ------ games -------- 1 | |---- 4 ------ PES -------- 3 | so now for showing it like a tree i did try but not worked : $result = mysql_query("SELECT * FROM Topics ORDER BY topicid"); while ($row = mysql_fetchrow($result)) { $id = intval($row['topicid']); $title = filter($row['topicname'], "nohtml"); $parent = $row['parent'] ; if ($parent==0) { $menu_item .= "<li><span class='folder'><a title = \"$alt\" href=\"modules.php?name=News&amp;new_topic=$id\">$title</a></span></li>"; }else { $result = mysql_query("SELECT * FROM ".$prefix."_Topics where parent='$id' ORDER BY topicid"); while ($row = mysql_fetchrow($result)) { $id = intval($row['topicid']); $title = filter($row['topicname'], "nohtml"); $parent = $row['parent'] ; $menu_item .= " <ul><li><span class='file'><a title = \"$alt\" href=\"modules.php?name=News&amp;new_topic=$id\">$title</a></span></li></ul>"; } } i dont know how to solve this

    Read the article

  • Pythagoras tree with g2d

    - by owca
    I'm trying to build my first fractal (Pythagoras Tree): in Java using Graphics2D. Here's what I have now : import java.awt.*; import java.awt.geom.*; import javax.swing.*; import java.util.Scanner; public class Main { public static void main(String[] args) { int i=0; Scanner scanner = new Scanner(System.in); System.out.println("Give amount of steps: "); i = scanner.nextInt(); new Pitagoras(i); } } class Pitagoras extends JFrame { private int powt, counter; public Pitagoras(int i) { super("Pythagoras Tree."); setSize(1000, 1000); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); powt = i; } private void paintIt(Graphics2D g) { double p1=450, p2=800, size=200; for (int i = 0; i < powt; i++) { if (i == 0) { g.drawRect((int)p1, (int)p2, (int)size, (int)size); counter++; } else{ if( i%2 == 0){ //here I must draw two squares } else{ //here I must draw right triangle } } } } @Override public void paint(Graphics graph) { Graphics2D g = (Graphics2D)graph; paintIt(g); } So basically I set number of steps, and then draw first square (p1, p2 and size). Then if step is odd I need to build right triangle on the top of square. If step is even I need to build two squares on free sides of the triangle. What method should I choose now for drawing both triangle and squares ? I was thinking about drawing triangle with simple lines transforming them with AffineTransform but I'm not sure if it's doable and it doesn't solve drawing squares.

    Read the article

  • Use SQL to clone a tree structure represented in a database

    - by AmoebaMan17
    Given a table that represents a hierarchical tree structure and has three columns ID (Primary Key, not-autoincrementing) ParentGroupID SomeValue I know the lowest most node of that branch, and I want to copy that to a new branch with the same number of parents that also need to be cloned. I am trying to write a single SQL INSERT INTO statement that will make a copy of every row that is of the same main has is part one GroupID into a new GroupID. Example beginning table: ID | ParentGroupID | SomeValue ------------------------ 1 | -1 | a 2 | 1 | b 3 | 2 | c Goal after I run a simple INSERT INTO statement: ID | ParentGroupID | SomeValue ------------------------ 1 | -1 | a 2 | 1 | b 3 | 2 | c 4 | -1 | a-cloned 5 | 4 | b-cloned 6 | 5 | c-cloned Final tree structure +--a (1) | +--b (2) | +--c (3) | +--a-cloned (4) | +--b-cloned (5) | +--c-cloned (6) The IDs aren't always nicely spaced out as this demo data is showing, so I can't always assume that the Parent's ID is 1 less than the current ID for rows that have parents. Also, I am trying to do this in T-SQL (for Microsoft SQL Server 2005 and greater). This feels like a classic exercise that should have a pure-SQL answer, but I'm too used to programming that my mind doesn't think in relational SQL.

    Read the article

  • Tree iterator, can you optimize this any further?

    - by Ron
    As a follow up to my original question about a small piece of this code I decided to ask a follow up to see if you can do better then what we came up with so far. The code below iterates over a binary tree (left/right = child/next ). I do believe there is room for one less conditional in here (the down boolean). The fastest answer wins! The cnt statement can be multiple statements so lets make sure this appears only once The child() and next() member functions are about 30x as slow as the hasChild() and hasNext() operations. Keep it iterative <-- dropped this requirement as the recursive solution presented was faster. This is C++ code visit order of the nodes must stay as they are in the example below. ( hit parents first then the children then the 'next' nodes). BaseNodePtr is a boost::shared_ptr as thus assignments are slow, avoid any temporary BaseNodePtr variables. Currently this code takes 5897ms to visit 62200000 nodes in a test tree, calling this function 200,000 times. void processTree (BaseNodePtr current, unsigned int & cnt ) { bool down = true; while ( true ) { if ( down ) { while (true) { cnt++; // this can/will be multiple statesments if (!current->hasChild()) break; current = current->child(); } } if ( current->hasNext() ) { down = true; current = current->next(); } else { down = false; current = current->parent(); if (!current) return; // done. } } }

    Read the article

  • Permuting output of a tree of closures

    - by yan
    This a conceptual question on how one would implement the following in Lisp (assuming Common Lisp in my case, but any dialect would work). Assume you have a function that creates closures that sequentially iterate over an arbitrary collection (or otherwise return different values) of data and returns nil when exhausted, i.e. (defun make-counter (up-to) (let ((cnt 0)) (lambda () (if (< cnt up-to) (incf cnt) nil)))) CL-USER> (defvar gen (make-counter 3)) GEN CL-USER> (funcall gen) 1 CL-USER> (funcall gen) 2 CL-USER> (funcall gen) 3 CL-USER> (funcall gen) NIL CL-USER> (funcall gen) NIL Now, assume you are trying to permute a combinations of one or more of these closures. How would you implement a function that returns a new closure that subsequently creates a permutation of all closures contained within it? i.e.: (defun permute-closures (counters) ......) such that the following holds true: CL-USER> (defvar collection (permute-closures (list (make-counter 3) (make-counter 3)))) CL-USER> (funcall collection) (1 1) CL-USER> (funcall collection) (1 2) CL-USER> (funcall collection) (1 3) CL-USER> (funcall collection) (2 1) ... and so on. The way I had it designed originally was to add a 'pause' parameter to the initial counting lambda such that when iterating you can still call it and receive the old cached value if passed ":pause t", in hopes of making the permutation slightly cleaner. Also, while the example above is a simple list of two identical closures, the list can be an arbitrarily-complicated tree (which can be permuted in depth-first order, and the resulting permutation set would have the shape of the tree.). I had this implemented, but my solution wasn't very clean and am trying to poll how others would approach the problem. Thanks in advance.

    Read the article

  • PHP: Convert <ul> <li> Tree HTML tag to an array

    - by marknt15
    Hi, I'm using jsTree and I need to convert this HTML tag tree code <ul> <li> to a PHP array. The jsTree HTML tag will be passed to PHP to be parsed and store in a structured tree PHP array(see below for the PHP array structure). Additional question: Is my desired PHP array structure good or you can suggest a good structure? I'm open for suggestions. Thanks in advance :) Cheers, Mark jsTree Screenshot: HTML Tree String: <ul class="ltr"> <li id="phtml_1" class=" open"> <a style="" class=" " href="#"><ins>&nbsp;</ins>Folder 1</a> <ul> <li class="leaf" id="phtml_2"> <a style="" class=" " href="#"><ins>&nbsp;</ins>Child 1.1</a> </li> <li class="open" id="phtml_3"> <a style="" class=" " href="#"><ins>&nbsp;</ins>Folder 1.1</a> <ul> <li class="leaf last" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Child 1.1.1</a> </li> </ul> </li> <li class="last open" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Folder 1.2</a> <ul> <li class="leaf" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Child 1.2.1</a> </li> <li class="leaf last" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Child 1.2.2</a> </li> </ul> </li> </ul> </li> <li id="phtml_5" class="file open"> <a style="" class=" " href="#"><ins>&nbsp;</ins>Folder 2</a> <ul> <li class="leaf" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Child 2.1</a> </li> <li class="leaf last" rel="default"> <a href="" style="" class="clicked"><ins>&nbsp;</ins>Child 2.2</a> </li> </ul> </li> <li class="leaf last" rel="default"> <a href="" style="" class=" "><ins>&nbsp;</ins>Outer Child</a> </li> </ul> PHP Array Structure: <?php $tree_array = array( 'Folder 1' => array( 'Child 1.1', 'Folder 1.1' => array( 'Child 1.1.1' ), 'Folder 1.2' => array( 'Child 1.2.1', 'Child 1.2.2' ), ), 'Folder 2' => array( 'Child 2.1', 'Child 2.2' ), 'Outer Child' ); echo '<pre>',print_r($tree_array),'</pre>'; ?> PHP print_r Output: Array ( [Folder 1] => Array ( [0] => Child 1.1 [Folder 1.1] => Array ( [0] => Child 1.1.1 ) [Folder 1.2] => Array ( [0] => Child 1.2.1 [1] => Child 1.2.2 ) ) [Folder 2] => Array ( [0] => Child 2.1 [1] => Child 2.2 ) [0] => Outer Child )

    Read the article

  • 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/)?

    Read the article

  • Why am I getting a " instance has no attribute '__getitem__' " error?

    - by Kevin Yusko
    Here's the code: class BinaryTree: def __init__(self,rootObj): self.key = rootObj self.left = None self.right = None root = [self.key, self.left, self.right] def getRootVal(root): return root[0] def setRootVal(newVal): root[0] = newVal def getLeftChild(root): return root[1] def getRightChild(root): return root[2] def insertLeft(self,newNode): if self.left == None: self.left = BinaryTree(newNode) else: t = BinaryTree(newNode) t.left = self.left self.left = t def insertRight(self,newNode): if self.right == None: self.right = BinaryTree(newNode) else: t = BinaryTree(newNode) t.right = self.right self.right = t def buildParseTree(fpexp): fplist = fpexp.split() pStack = Stack() eTree = BinaryTree('') pStack.push(eTree) currentTree = eTree for i in fplist: if i == '(': currentTree.insertLeft('') pStack.push(currentTree) currentTree = currentTree.getLeftChild() elif i not in '+-*/)': currentTree.setRootVal(eval(i)) parent = pStack.pop() currentTree = parent elif i in '+-*/': currentTree.setRootVal(i) currentTree.insertRight('') pStack.push(currentTree) currentTree = currentTree.getRightChild() elif i == ')': currentTree = pStack.pop() else: print "error: I don't recognize " + i return eTree def postorder(tree): if tree != None: postorder(tree.getLeftChild()) postorder(tree.getRightChild()) print tree.getRootVal() def preorder(self): print self.key if self.left: self.left.preorder() if self.right: self.right.preorder() def inorder(tree): if tree != None: inorder(tree.getLeftChild()) print tree.getRootVal() inorder(tree.getRightChild()) class Stack: def __init__(self): self.items = [] def isEmpty(self): return self.items == [] def push(self, item): self.items.append(item) def pop(self): return self.items.pop() def peek(self): return self.items[len(self.items)-1] def size(self): return len(self.items) def main(): parseData = raw_input( "Please enter the problem you wished parsed.(NOTE: problem must have parenthesis to seperate each binary grouping and must be spaced out.) " ) tree = buildParseTree(parseData) print( "The post order is: ", + postorder(tree)) print( "The post order is: ", + postorder(tree)) print( "The post order is: ", + preorder(tree)) print( "The post order is: ", + inorder(tree)) main() And here is the error: Please enter the problem you wished parsed.(NOTE: problem must have parenthesis to seperate each binary grouping and must be spaced out.) ( 1 + 2 ) Traceback (most recent call last): File "C:\Users\Kevin\Desktop\Python Stuff\Assignment 11\parseTree.py", line 108, in main() File "C:\Users\Kevin\Desktop\Python Stuff\Assignment 11\parseTree.py", line 102, in main tree = buildParseTree(parseData) File "C:\Users\Kevin\Desktop\Python Stuff\Assignment 11\parseTree.py", line 46, in buildParseTree currentTree = currentTree.getLeftChild() File "C:\Users\Kevin\Desktop\Python Stuff\Assignment 11\parseTree.py", line 15, in getLeftChild return root[1] AttributeError: BinaryTree instance has no attribute '__getitem__'

    Read the article

  • binary search tree recursive subtree in java

    - by Art Peterson
    Can anyone point me to a code example (java preferably) or psuedocode that uses recursion to return a subtree that contains all nodes with keys between fromKey and toKey. So if I was to call Tree.subtree(5,10) it should return all nodes in the BST that have keys between 5 and 10 inclusive - but I can't use loops or helper methods...only recursive calls to the subtree method, which takes fromKey and toKey as parameters. Thanks!

    Read the article

  • asp.net mvc tree view with checkbox

    - by mazhar
    Ok I am looking for a solution in mvc2 where i can have tree view generated where after that i can checked the nodes I want to enter the value in the database. Can anyone point me to something? Basically I am assigning features to a particular group.(I have a group admin whom I can assign the manage user add edit delete,manage groups delete,manage teacher add edit feature Can someone point me to some other technique that i can implement?

    Read the article

  • Android Source Code Tree Structure

    - by Walidix
    I have downloaded Android source code but I don't find the "Kernel Directory" in the top level directory of the source code tree. Is it normal ???? or is it missing ??? /mydroid$ find . -name kernel ./bionic/libc/kernel ./vendor/htc/sapphire-open/kernel ./vendor/htc/dream-open/kernel ./dalvik/libcore/luni-kernel/src/test/java/tests/api/org/apache/harmony/kernel ./dalvik/libcore/luni-kernel/src/main/java/org/apache/harmony/kernel ./prebuilt/android-arm/kernel ./prebuilt/android-x86/kernel ./device/htc/passion/kernel

    Read the article

  • Parse XML tree with no id using LINQ to XML

    - by Danny
    Requirement I want to read a XML tree, fill my objects with encountered attributes and after every run a method (insert it into my db). The amount of parents is not specified, also the order is not specified, it could be, address-death-death-address-address for example Input file Overview: <Root> <Element> <Element2> <Parent> <Child> <Grandchild> <Grandchild> </Child> </Parent> </Element2> </Element1> </Root> Full example: <?xml version="1.0" encoding="utf-8" ?> <Root> <Element1> <Element2> <Parent> <Child> <Grandchild> <number>01</number> <name>Person</name> <Rows> <Row> <number>0110</number> <name>ID</name> <value>123456789</value> </Row> </Rows> </Grandchild> <Grandchild> <number>08</number> <name>Address</name> <Rows> <Row> <number>1110</number> <name>street</name> <value>first aveneu</value> </Row> <Row> <number>1120</number> <name>streetnumber</name> <value>345</value> </Row> <Row> <number>1130</number> <name>zip</name> <value>2938PS</value> </Row> <Row> <number>1160</number> <name>country</name> <value>Germany</value> </Row> </Rows> </Grandchild> </Child> </Parent> <Parent> <Child> <Grandchild> <number>01</number> <name>Person</name> <Rows> <Row> <number>0110</number> <name>ID</name> <value>987654321</value> </Row> </Rows> </Grandchild> <Grandchild> <number>06</number> <name>Death</name> <Rows> <Row> <number>0810</number> <name>date</name> <value>2012-01-03</value> </Row> <Row> <number>0820</number> <name>placeOfDeath</name> <value>attic</value> </Row> <Row> <number>0830</number> <name>funeral</name> <value>burrial</value> </Row> </Rows> </Grandchild> </Child> </Parent> </Element2> </Element1> </Root> Desired result After encounter of parent determine type of grandchild (number 6 is death number 8 is address) Every parent has ALWAYS grandchild number 1 'Person', the second grandchild is either death or address. reading first parent Person person = new Person(); person.ID = value; <--- filled with 123456789 person.street = value; <--- filled with first aveneu person.streetnumber = value; <--- filled with 345 person.zip = value; <--- filled with 2938PS person.country = value; <--- filled with germany person.DoMethod(); // inserts the value in db Continue reading next parent. Person person = new Person(); person.ID = value; <--- filled with 987654321 person.date = value; <--- filled with 2012-01-03 person.placeOfDeath = value; <--- filled with attic person.funeral = value; <--- filled with burrial person.DoMethod(); // insert the values in db Continue reading till no parents found EDIT: how do I target the name element of the second grandchild for every child? Like address or death Code/Credit I got no further then this, with help of Daniel Hilgarth: Linq to XML (C#) parse XML tree with no attributes/id to object The XML tree has changed, and I am really stuck.. in the meantime I try to post new working code...

    Read the article

  • Expression Tree Binary Expression for an 'In' operation

    - by Adam Driscoll
    I'm trying to build an expression tree (still) but getting further! I need to create a BinaryExpression to perform an 'In' comparison between a Member and a collection of items. Hence, the expression should return true if the member is contained within the items. This obviously does not exist: Expression.MakeBinary(ExpressionType.In, memberExpression, constantExpression); constantExpression is a ConstantExpression of type IEnumerable while memberExpression is a MemberExpression of type T. How would I create such an expression?

    Read the article

  • Trie VS Suffix Tree VS Suffix Array

    - by ukrania
    Hello everyone, Which one is the structure that provides best performance results? Trie, Suffix Tree or Suffix Array? There are other equivalent structures? What are good Java implementations of these structures? Thanks for your answers. Best Regards, ukrania

    Read the article

  • is there anyway to clean up old svn directories and files from old source code tree

    - by oo
    i have been sent a directory tree of source code that i want to import into my subversion repository. The issue is that at some point this code was in a different subversion repository. There are a huge number of directories and subdirectories and i basically want to clean up all of the subversion .svn folders before i attempt to import to a new repository and i dont want svn to get confused. is there anyway to clean out a directory structure to remove all svn references?

    Read the article

  • Sorting tree with other column in SQL Server 2008

    - by bodziec
    Hi, I have a table which implements a tree using hierarchyid column Sample data: People \ Girls \1\ Zoey \1\1\ Kate \1\2\ Monica \1\3\ Boys \2\ Mark \2\1\ David \2\2\ This is the order using hierarchyid column as sort column I would like to sort data using hierarchyid but also using name so it would look like this: People \ Boys \2\ David \2\2\ Mark \2\1\ Girls \1\ Kate \1\2\ Monica \1\3\ Zoey \1\1\ Is there a simple solution to do this? Czy da sie to zrobic w jednym zapytaniu sql ?

    Read the article

  • nearest neighbor - k-d tree - wikipedia proof.

    - by user123930
    On the wikipedia entry for k-d trees, an algorithm is presented for doing a nearest neighbor search on a k-d tree. What I don't understand is the explanation of step 3.2. How do you know there isn't a closer point just because the difference between the splitting coordinate of the search point and the current node is greater than the difference between the splitting coordinate of the search point and the current best?

    Read the article

< Previous Page | 19 20 21 22 23 24 25 26 27 28 29 30  | Next Page >