Search Results

Search found 3826 results on 154 pages for 'graph theory'.

Page 34/154 | < Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >

  • Post wall message on facebook account

    - by Zeroshade
    Hello, I am trying to implement some functionality in a blackberry app, that I saw in other application. Basically it's a window that has a message, and a Facebook icon. When you click on the icon it launches a new window, this window asks the user for permissions(user and password), and then the message is posted in the user's wall. So my question is how can I replicate that?. I have been looking at the graph api, but I just can't figure out how to do all of this in one step. I mean just typing the url in the browser, and some post data. Thanks a lot.

    Read the article

  • Finding the longest road in a Settlers of Catan game algorithmically

    - by Jay
    I'm writing a Settlers of Catan clone for a class. One of the extra credit features is automatically determining which player has the longest road. I've thought about it, and it seems like some slight variation on depth-first search could work, but I'm having trouble figuring out what to do with cycle detection, how to handle the joining of a player's two initial road networks, and a few other minutiae. How could I do this algorithmically? For those unfamiliar with the game, I'll try to describe the problem concisely and abstractly: I need to find the longest possible path in an undirected cyclic graph.

    Read the article

  • help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code

    - by Pitelk
    Hi , does anyone know the Donald B. Johnson's algorithm which enumarates all the elementary circuits (cycles) in a Directed graph? link text I have the paper he had published in 1975 but I cannot understand the pseudo-code. My goal is to implement this algorithm in java. Some questions i have is for example what is the matrix Ak it refers to. In the pseudo code mentions that Ak:=adjacency structure of strong component K with least vertex in subgraph of G induced by {s,s+1,....n}; Does that mean i have to implement another algorithm that finds the Ak matrix? Another question is what the following means? begin logical f; Does also the line "logical procedure CIRCUIT (integer value v);" means that the circuit procedure returns a logical variable. In the pseudo code also has the line "CIRCUIT := f;" . Does this mean? It would be great if someone could translate this 1970's pseudocode to a more modern type of pseudo code so i can understand it in case you are interested to help but you cannot find the paper please email me at [email protected] and i will send you the paper. Thanks in advance

    Read the article

  • Facebook SDK Comment Deleting

    - by mwoodworth
    Working with the Facebook php SDK's, I am having a lot of trouble figuring out how to delete comments, given its id and xid. At first I was using the REST API, where you can call 'comments_remove($xid, $id);' to delete a comment. The problem with this method came when the xid parameter only accepts alphanumeric characters and underscores. Based on the documentation (http://developers.facebook.com/docs/reference/fbml/comments ) a valid XID can be the result of any url_encode. Now I am testing my luck with the new GRAPH api. Looking at http://developers.facebook.com/docs/api under 'Deleting Objects', It seems that comment deleting is definitely supported. However, I have tried sending a DELETE request, and I have also tried sending POST and GET to the object url with the argument 'method=delete'. No matter how I try it, I always get the same error: {"error":{"type":"GraphMethodException","message":"Unsupported delete request."}} I am sending the access token as a parameter as well. The access token that I am sending is the access token saved in the facebook cookie from the single sign on javascript cookie. These are all comments made on my application. Does this happen to anyone else, or am I simply not doing this right? Any help or guidance is GREATLY appreciated.

    Read the article

  • How to create closed areas (convex polygons) from set of line segments ?

    - by Marten
    The following problem is in 2D, so some simplifications can be made when suggesting answers. I need to create closed areas (defined either by line segments or just set of points - convex polygon) from a set of points/line segments. Basically I used Voronoi to generate "roads". Then I changed some of the data. Now I need a way to loop through that data (which is still line segments but doesn't comply with Voronoi anymore) and generate "neigbourhoods" that are bordered with the "roads". I looked at some graph diagrams and shortest path theories, but I could not figure it out. Logically it could be done by starting at left edge from one point, finding the way back to that point using the shortest path with available lines (using only clockwise directions). Then mark this line set down and remove from the data. Then you can repeat the same process and get all the areas like that. I tried to implement that but it did not get me anywhere as I could not figure out a way to write a C++ code that could do that. Problem was with choosing the most counterclockwise line from available lines from a specific point. All angle based math I did gave wrong answers because the way sin/cos are implemented in c++. So to summarize - if you can help me with a totally new approach to the problem its good, if not could you help me find a way to write the part of the code that finds the shortest clockwise path back to the beginning point using the line segment set as paths back. Thank you for your help!

    Read the article

  • ArrayList<String> NullPointerException

    - by Carlucho
    Am trying to solve a labyrinth by DFS, using adj List to represent the vertices and edges of the graph. In total there are 12 nodes (3 rows[A,B,C] * 4 cols[0,..,3]). My program starts by saving all the vertex labels (A0,..C3), so far so good, then checks the adjacent nodes, also no problems, if movement is possible, it proceeds to create the edge, here its where al goes wrong. adjList[i].add(vList[j].label); I used the debugger and found that vList[j].label is not null it contains a correct string (ie. "B1"). The only variables which show null are in adjList[i], which leads me to believe i have implemented it wrongly. this is how i did it. public class GraphList { private ArrayList<String>[] adjList; ... public GraphList(int vertexcount) { adjList = (ArrayList<String>[]) new ArrayList[vertexCount]; ... } ... public void addEdge(int i, int j) { adjList[i].add(vList[j].label); //NULLPOINTEREXCEPTION HERE } ... } I will really appreaciate if anyone can point me on the right track regrading to what its going wrong... Thanks!

    Read the article

  • Facebook app request in java not working

    - by Arpit Solanki
    I am trying to send a facebook app request to a user through the code below.But it gives an IO Exception and HTTP status code 400 in running.I dont see a any app request being sent to a user on running this. StringBuffer buffer = new StringBuffer(); buffer.append("access_token").append('=').append(this.app_access_token); buffer.append('&').append("message=").append("sent an app request!"); String content = buffer.toString(); try{ URLConnection connection = new URL("https://graph.facebook.com/me/apprequests").openConnection(); connection.setDoOutput(true); connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded"); connection.setRequestProperty("Content-Length",Integer.toString(content.length())); DataOutputStream outs = new DataOutputStream(connection.getOutputStream()); outs.writeBytes(content); outs.flush(); outs.close(); BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())); String inputLine; while ((inputLine = in.readLine()) != null) { System.out.println(inputLine); } in.close(); } catch(Exception e){ System.out.println(e); }

    Read the article

  • Is it a good idea to use MySQL and Neo4j together?

    - by Sanoj
    I will make an application with a lot of similar items (millions), and I would like to store them in a MySQL database, because I would like to do a lot of statistics and search on specific values for specific columns. But at the same time, I will store relations between all the items, that are related in many connected binary-tree-like structures (transitive closure), and relation databases are not good at that kind of structures, so I would like to store all relations in Neo4j which have good performance for this kind of data. My plan is to have all data except the relations in the MySQL database and all relations with item_id stored in the Neo4j database. When I want to lookup a tree, I first search the Neo4j for all the item_id:s in the tree, then I search the MySQL-database for all the specified items in a query that would look like: SELECT * FROM items WHERE item_id = 45 OR item_id = 345435 OR item_id = 343 OR item_id = 78 OR item_id = 4522 OR item_id = 676 OR item_id = 443 OR item_id = 4255 OR item_id = 4345 Is this a good idea, or am I very wrong? I haven't used graph-databases before. Are there any better approaches to my problem? How would the MySQL-query perform in this case?

    Read the article

  • PHP Facebook Cronjob with offline access

    - by Mohamed Salem
    1:the code to greet the user, ask for his permission and store his session data so that we can use a cronjob with his session data afterwards. <?php $db_server = "localhost"; $db_username = "username"; $db_password = "password"; $db_name = "databasename"; #go to line 85, the script actually starts there mysql_connect($db_server,$db_username,$db_password); mysql_select_db($db_name); #you have to create a database to store session values. #if you do not know what columns there should be look at line 76 to see column names. #make them all varchars # Now lets load the FB GRAPH API require './facebook.php'; // Create our Application instance. global $facebook; $facebook = new Facebook(array( 'appId' => '121036530138', 'secret' => '9bbec378147064', 'cookie' => false,)); # Lets set up the permissions we need and set the login url in case we need it. $par['req_perms'] = "friends_about_me,friends_education_history,friends_likes, friends_interests,friends_location,friends_religion_politics, friends_work_history,publish_stream,friends_activities, friends_events, friends_hometown,friends_location ,user_interests,user_likes,user_events, user_about_me,user_status,user_work_history,read_requests, read_stream,offline_access,user_religion_politics,email,user_groups"; $loginUrl = $facebook->getLoginUrl($par); function save_session($session){ global $facebook; # OK lets go to the database and see if we have a session stored $sid=mysql_query("Select access_token from facebook_user WHERE uid =".$session['uid']); $session_id=mysql_fetch_row($sid); if (is_array($session_id)) { # We have a stored session, but is it valid? echo " We have a session, but is it valid?"; try { $attachment = array('access_token' => $session_id[0]); $ret_code=$facebook->api('/me', 'GET', $attachment); } catch (Exception $e) { # We don't have a good session so echo " our old session is not valid, let's delete saved invalid session data "; $res = mysql_query("delete from facebook_user WHERE uid =".$session['uid']); #save new good session #to see what is our session data: print_r($session); if (is_array($session)) { $sql="insert into facebook_user (session_key,uid,expires,secret,access_token,sig) VALUES ('".$session['session_key']."','".$session['uid']."','". $session['expires']."','". $session['secret'] ."','" . $session['access_token']."','". $session['sig']."');"; $res = mysql_query($sql); return $session['access_token']; } # this should never ever happen echo " Something is terribly wrong: Our old session was bad, and now we cannot get the new session"; return; } echo " Our old stored session is valid "; return $session_id[0]; } else { echo " no stored session, this means the user never subscribed to our application before. "; # let's store the session $session = $facebook->getSession(); if (is_array($session)) { # Yes we have a session! so lets store it! $sql="insert into facebook_user (session_key,uid,expires,secret,access_token,sig) VALUES ('".$session['session_key']."','".$session['uid']."','". $session['expires']."','". $session['secret'] ."','". $session['access_token']."','". $session['sig']."');"; $res = mysql_query($sql); return $session['access_token']; } } } #this is the first meaningful line of this script. $session = $facebook->getSession(); # Is the user already subscribed to our application? if ( is_null($session) ) { # no he is not #send him to permissions page header( "Location: $loginUrl" ); } else { #yes, he is already subscribed, or subscribed just now #in case he just subscribed now, save his session information $access_token=save_session($session); echo " everything is ok"; # write your code here to do something afterwards } ?> error Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/content/28/9687528/html/ss/src/indexx.php:1) in /home/content/28/9687528/html/ss/src/facebook.php on line 49 Fatal error: Call to undefined method Facebook::getSession() in /home/content/28/9687528/html/ss/src/indexx.php on line 86 2:A cronjob template that reads the stored session of a user from database, uses his session data to work on his behalf, like reading status posts or publishing posts etc. <?php $db_server = "localhost"; $db_username = "username"; $db_password = "pass"; $db_name = "database"; # Lets connect to the Database and set up the table $link = mysql_connect($db_server,$db_username,$db_password); mysql_select_db($db_name); # Now lets load the FB GRAPH API require './facebook.php'; // Create our Application instance. global $facebook; $facebook = new Facebook(array( 'appId' => 'appid', 'secret' => 'secret', 'cookie' => false, )); function get_check_session($uidCheck){ global $facebook; # This function basically checks for a stored session and if we have one it returns it # OK lets go to the database and see if we have a session stored $sid=mysql_query("Select access_token from facebook_user WHERE uid =".$uidCheck); $session_id=mysql_fetch_row($sid); if (is_array($session_id)) { # We have a session # but, is it valid? try { $attachment = array('access_token' => $session_id[0],); $ret_code=$facebook->api('/me', 'GET', $attachment); } catch (Exception $e) { # We don't have a good session so echo " User ".$uidCheck." removed the application, or there is some other access problem. "; # let's delete stored data $res = mysql_query("delete from facebook_user where WHERE uid =".$uidCheck); return; } return $session_id[0]; } else { # "no stored session"; echo " error:newsFeedcrontab.php No stored sessions. This should not have happened "; } } # get all users that have given us offline access $users = getUsers(); foreach($users as $user){ # now for each user, check if they are still subscribed to our application echo " Checking user".$user; $access_token=get_check_session($user); # If we've not got an access_token we actually need to login. # but in the crontab, we just log the error, there is no way we can find the user to give us permission here. if ( is_null($access_token) ) { echo " error: newsFeedcrontab.php There is no access token for the user ".$user." "; } else { #we are going to read the newsfeed of user. There are user's friends' posts in this newsfeed try{ $attachment = array('access_token' => $access_token); $result=$facebook->api('/me/home', 'GET', $attachment); }catch(Exception $e){ echo " error: newsfeedcrontab.php, cannot get feed of ".$user.$e; } #do something with the result here #but what does the result look like? #go to http://developers.facebook.com/docs/reference/api/user/ and click on the "home" link under connections #we can also read the home of user. Home is the wall of the user who has given us offline access. try{ $attachment = array('access_token' => $access_token); $result=$facebook->api('/me/feed', 'GET', $attachment); }catch(Exception $e){ echo " error: newsfeedcrontab.php, cannot get wall of ".$user.$e; } #do something with the result here # #but what does the result look like? #go to http://developers.facebook.com/docs/reference/api/user/ and click on the "feed" link under connections } } function getUsers(){ $sql = "SELECT distinct(uid) from facebook_user Where 1"; $result = mysql_query($sql); while($row = mysql_fetch_array($result)){ $rows [] = $row['uid']; } print_r($rows); return $rows; } mysql_close($link); ?> error Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/content/28/9687528/html/ss/src/cron.php:1) in /home/content/28/9687528/html/ss/src/facebook.php on line 49 Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/content/28/9687528/html/ss/src/cron.php on line 110 Warning: Invalid argument supplied for foreach() in /home/content/28/9687528/html/ss/src/cron.php on line 64

    Read the article

  • Creating transparent gridlines

    - by Rob Penridge
    I'm trying to get the chart's gridlines to be transparent but it doesn't seem to be supported: http://support.sas.com/documentation/cdl/en/grstatug/63302/HTML/default/viewer.htm#n1f71f6e9v037an1jy274v66z4r1.htm I'm doing to try and blend the gridlines with the chart background color (which in my code can change between colors) which would make the gridlines subtle rather than jarring when background colors change. Here is my code: ** ** TAKE THE DEFAULT STYLE BEING USED. MODIFY IT SO THAT ** GRAPH GRIDLINES WILL BE GREEN AND MOSTLY TRANSPARENT *; proc template; define style my_style; parent = styles.default; style GraphGridLines from GraphGridLines / contrastcolor=green transparency=.05; end; run; ** ** LAYOUT TEMPLATE FOR A SIMPLE SERIES CHART *; proc template; define statgraph mychart; begingraph; layout overlay / wallcolor=black xaxisopts=(display=(line) griddisplay=on) yaxisopts=(display=(line)) ; seriesplot x=name y=height / lineattrs=(color=white); endlayout; endgraph; end; run; ** ** PLOT SAMPLE DATA USING CUSTOM STYLE AND CHART LAYOUT WE JUST DEFINED *; ods graphics / width=640 height=640 ; ods html style=my_style; proc sgrender data=sashelp.class template=mychart; run; ods html close; Is there another way to achieve this effect by blending the green color with the background color?

    Read the article

  • Getting a "for each" loop in Java to run in different order everytime

    - by R Stokes
    Hi, Basically my problem is that I'm trying to write a method that finds a random path in a graph of strings, which takes as it's parameters a start string, an integer length and a Vector of strings that will store the path. I'm attempting to do this by first adding the starting string to our blank vector, recursing through its neighbors until the vector's length (not including the start node) is the same as the integer length specified in the parameters. I've provided my code so far here: public Vector<String> findRandomPathFrom(String n, int len, Vector<String> randomPath){ randomPath.add(n); if (randomPath.size() == len + 1) return randomPath; for (String m : this.neighbours(n)){ if (!randomPath.contains(m) && findRandomPathFrom(m, len, randomPath) != null) return randomPath; } path.setSize(path.size() - 1); return null; } It seems to be working fine, returning a path with exactly the number of strings specified after the given start string. However, for any given starting string it generates the EXACT same path everytime, which kind of defeats the purpose of it being a random path generator. I'm guessing this problem is related to my "for each" loop, which loops through all the neighbouring strings of your current string. It seems to just be going with the first string in the neighbours vector every single time. Can anyone help me fix this problem so that it will choose a random neighbour instead of going in order? tl;dr - Any way of getting a "for each" loop in java to process a collection in a random order as oppoosed to start-to-finsih? Thanks in advance

    Read the article

  • Facebook Page Statuses API

    - by Simon R
    I've got a curl function in php which posts a status update to our facebook page. However, when I post the update it makes the status appear from me personally rather than me the group. Does anyone know how you can post as administrator of the group. The script is as follows; $xPost['access_token'] = "[key]" $xPost['message'] = "Posting a message test."; $query = http_build_query($xPost); $ch = curl_init('https://graph.facebook.com/broadland/feed'); curl_setopt($ch, CURLOPT_VERBOSE, 1); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HEADER, 1); curl_setopt($ch, CURLOPT_TIMEOUT, 120); curl_setopt($ch, CURLOPT_POST, 1); curl_setopt($ch, CURLOPT_POSTFIELDS, $query); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 1); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); curl_setopt($ch, CURLOPT_CAINFO, NULL); curl_setopt($ch, CURLOPT_CAPATH, NULL); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0); $result = curl_exec($ch);

    Read the article

  • drawing graphs in php

    - by user434885
    i am using php to generate graphs from arrays. I wish to create multiple graphs on the same page as i need to design a summary report from answers extracted from a database. Currently i am using this code and am only able to get one single graph. what additions to the code do i need to make to get multiple graphs? <?php function draw_graph($values) { // Get the total number of columns we are going to plot $columns = count($values); // Get the height and width of the final image $width = 300; $height = 200; // Set the amount of space between each column $padding = 5; // Get the width of 1 column $column_width = $width / $columns ; // Generate the image variables $im = imagecreate($width,$height); $gray = imagecolorallocate ($im,0xcc,0xcc,0xcc); $gray_lite = imagecolorallocate ($im,0xee,0xee,0xee); $gray_dark = imagecolorallocate ($im,0x7f,0x7f,0x7f); $white = imagecolorallocate ($im,0xff,0xff,0xff); // Fill in the background of the image imagefilledrectangle($im,0,0,$width,$height,$white); $maxv = 0; // Calculate the maximum value we are going to plot for($i=0;$i<$columns;$i++)$maxv = max($values[$i],$maxv); // Now plot each column for($i=0;$i<$columns;$i++) { $column_height = ($height / 100) * (( $values[$i] / $maxv) *100); $x1 = $i*$column_width; $y1 = $height-$column_height; $x2 = (($i+1)*$column_width)-$padding; $y2 = $height; imagefilledrectangle($im,$x1,$y1,$x2,$y2,$gray_dark); } header ("Content-type: image/png"); imagepng($im); imagedestroy($im); } $values = array("23","32","35","57","12"); $values2 = array("123","232","335","157","102"); draw_graph($values2); draw_graph($values);//no output is coming draw_graph($values2);//no output is coming draw_graph($values);//no output is coming ?>

    Read the article

  • Is there a free tool which can help visualize the logic of a stored procedure in SQL Server 2008 R2?

    - by Hamish Grubijan
    I would like to be able to plot a call graph of a stored procedure. I am not interested in every detail, and I am not concerned with dynamic SQL (although it would be cool to detect it and skip it maybe or mark it as such.) I would like the tool to generate a tree for me, given the server name, db name, stored proc name, a "call tree", which includes: Parent stored procedure. Every other stored procedure that is being called as a child of the caller. Every table that is being modified (updated or deleted from) as a child of the stored proc which does it. Hopefully it is clear what I am after; if not - please do ask. If there is not a tool that can do this, then I would like to try to write one myself. Python 2.6 is my language of choice, and I would like to use standard libraries as much as possible. Any suggestions? EDIT: For the purposes of bounty Warning: SQL syntax is COMPLEX. I need something that can parse all kinds of SQL 2008, even if it looks stupid. No corner cases barred :) EDIT2: I would be OK if all I am missing is graphics.

    Read the article

  • Facebook API - Detect if session is active OR NOT active

    - by Tom Doe
    I'm sure I'm simply overlooking something in the Facebook API docs. Basically, after I've loaded the FB Graph, I need to know if the session is active... I cannot simply assume they're logged out and simply re-render if they're logged in once the 'auth.statusChange' event is triggered. I need to know right off the bat. Below is the code that I've used. Most importantly the FB.getLoginStatus/getAuthResponse/getAccessToken don't work like I'd expect; essentially where it indicates, when invoked, whether they're logged in or out. (function(d) { // Create fb-root var fb_root = document.createElement('div'); fb_root.id = "fb-root"; document.getElementsByTagName('body')[0].appendChild( fb_root ); // Load FB Async var js, id = 'facebook-jssdk', ref = d.getElementsByTagName('script')[0]; if (d.getElementById(id)) {return;} js = d.createElement('script'); js.id = id; js.async = true; js.src = "//connect.facebook.net/en_US/all.js"; ref.parentNode.insertBefore(js, ref); // App config-data var config = { appId : XXXX, cookie: true, status: true, frictionlessRequests: true }; window.fbAsyncInit = function() { // This won't work. // I can't assume they're logged out and rely on this to tell me they're logged in. FB.Event.subscribe('auth.statusChange', function(response) {}); // Init FB.init(config); // These do not inidicate if the user is logged out :( FB.getLoginStatus(function(response) { }); FB.getAuthResponse(function(response) { }); FB.getAccessToken(function(response) { }); }; }(document)); Any help is much appreciated. :)

    Read the article

  • Removing Left Recursion in ANTLR

    - by prosseek
    As is explained in http://stackoverflow.com/questions/2652060/removing-left-recursion , there are two ways to remove the left recursion. Modify the original grammar to remove the left recursion using some procedure Write the grammar originally not to have the left recursion What people normally use for removing (not having) the left recursion with ANTLR? I've used flex/bison for parser, but I need to use ANTLR. The only thing I'm concerned about using ANTLR (or LL parser in genearal) is left recursion removal. In practical sense, how serious of removing left recursion in ANTLR? Is this a showstopper in using ANTLR? Or, nobody cares about it in ANTLR community? I like the idea of AST generation of ANTLR. In terms of getting AST quick and easy way, which method (out of the 2 removing left recursion methods) is preferable?

    Read the article

  • Boosting my GA with Neural Networks and/or Reinforcement Learning

    - by AlexT
    As I have mentioned in previous questions I am writing a maze solving application to help me learn about more theoretical CS subjects, after some trouble I've got a Genetic Algorithm working that can evolve a set of rules (handled by boolean values) in order to find a good solution through a maze. That being said, the GA alone is okay, but I'd like to beef it up with a Neural Network, even though I have no real working knowledge of Neural Networks (no formal theoretical CS education). After doing a bit of reading on the subject I found that a Neural Network could be used to train a genome in order to improve results. Let's say I have a genome (group of genes), such as 1 0 0 1 0 1 0 1 0 1 1 1 0 0... How could I use a Neural Network (I'm assuming MLP?) to train and improve my genome? In addition to this as I know nothing about Neural Networks I've been looking into implementing some form of Reinforcement Learning, using my maze matrix (2 dimensional array), although I'm a bit stuck on what the following algorithm wants from me: (from http://people.revoledu.com/kardi/tutorial/ReinforcementLearning/Q-Learning-Algorithm.htm) 1. Set parameter , and environment reward matrix R 2. Initialize matrix Q as zero matrix 3. For each episode: * Select random initial state * Do while not reach goal state o Select one among all possible actions for the current state o Using this possible action, consider to go to the next state o Get maximum Q value of this next state based on all possible actions o Compute o Set the next state as the current state End Do End For The big problem for me is implementing a reward matrix R and what a Q matrix exactly is, and getting the Q value. I use a multi-dimensional array for my maze and enum states for every move. How would this be used in a Q-Learning algorithm? If someone could help out by explaining what I would need to do to implement the following, preferably in Java although C# would be nice too, possibly with some source code examples it'd be appreciated.

    Read the article

  • Advantages of compilers for functional languages over compilers for imperative languages

    - by Onorio Catenacci
    As a follow up to this question What are the advantages of built-in immutability of F# over C#?--am I correct in assuming that the F# compiler can make certain optimizations knowing that it's dealing with largely immutable code? I mean even if a developer writes "Functional C#" the compiler wouldn't know all of the immutability that the developer had tried to code in so that it couldn't make the same optimizations, right? In general would the compiler of a functional language be able to make optimizations that would not be possible with an imperative language--even one written with as much immutability as possible?

    Read the article

  • What are modern and old compilers written in?

    - by ulum
    As a compiler, other than an interpreter, only needs to translate the input and not run it the performance of itself should be not that problematic as with an interpreter. Therefore, you wouldn't write an interpreter in, let's say Ruby or PHP because it would be far too slow. However, what about compilers? If you would write a compiler in a scripting language maybe even featuring rapid development you could possibly cut the source code and initial development time by halv, at least I think so. To be sure: With scripting language I mean interpreted languages having typical features that make programming faster, easier and more enjoyable for the programmer, usually at least. Examples: PHP, Ruby, Python, maybe JavaScript though that may be an odd choice for a compiler What are compilers normally written in? As I suppose you will respond with something low-level like C, C++ or even Assembler, why? Are there compilers written in scripting languages? What are the (dis)advantages of using low or high level programming languages for compiler writing?

    Read the article

  • Translate a<b to IR Trees

    - by drozzy
    I have to translate the mini-java (java like language) statements into intermediate-representation trees. But for this question I have no idea what it is asking... a>b moves a 1 or 0 into some newly defined temporary, and whose right-hand side is a temporary Does the wording make sense to anyone? (I am using the Java compilers book, and it is question 7.2d) in ch7.)

    Read the article

  • Shift-reduce: when to stop reducing?

    - by Joey Adams
    I'm trying to learn about shift-reduce parsing. Suppose we have the following grammar, using recursive rules that enforce order of operations, inspired by the ANSI C Yacc grammar: S: A; P : NUMBER | '(' S ')' ; M : P | M '*' P | M '/' P ; A : M | A '+' M | A '-' M ; And we want to parse 1+2 using shift-reduce parsing. First, the 1 is shifted as a NUMBER. My question is, is it then reduced to P, then M, then A, then finally S? How does it know where to stop? Suppose it does reduce all the way to S, then shifts '+'. We'd now have a stack containing: S '+' If we shift '2', the reductions might be: S '+' NUMBER S '+' P S '+' M S '+' A S '+' S Now, on either side of the last line, S could be P, M, A, or NUMBER, and it would still be valid in the sense that any combination would be a correct representation of the text. How does the parser "know" to make it A '+' M So that it can reduce the whole expression to A, then S? In other words, how does it know to stop reducing before shifting the next token? Is this a key difficulty in LR parser generation?

    Read the article

< Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >