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  • parsing of mathematical expressions

    - by gcc
    (in c90) (linux) input: sqrt(2 - sin(3*A/B)^2.5) + 0.5*(C*~(D) + 3.11 +B) a b /*there are values for a,b,c,d */ c d input: cos(2 - asin(3*A/B)^2.5) +cos(0.5*(C*~(D)) + 3.11 +B) a b /*there are values for a,b,c,d */ c d input: sqrt(2 - sin(3*A/B)^2.5)/(0.5*(C*~(D)) + sin(3.11) +ln(B)) /*max lenght of formula is 250 characters*/ a b /*there are values for a,b,c,d */ c /*each variable with set of floating numbers*/ d As you can see infix formula in the input depends on user. My program will take a formula and n-tuples value. Then it calculate the results for each value of a,b,c and d. If you wonder I am saying ;outcome of program is graph. /sometimes,I think i will take input and store in string. then another idea is arise " I should store formula in the struct" but i don't know how I can construct the code on the base of structure./ really, I don't know way how to store the formula in program code so that I can do my job. can you show me? /* a,b,c,d is letters cos,sin,sqrt,ln is function*/

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  • Mapping individual buttons on ASP.NET MVC View to controller actions

    - by skb
    I have an application where I need the user to be able to update or delete rows of data from the database. The rows are displayed to the user using a foreach loop in the .aspx file of my view. Each row will have two text fields (txtName, txtDesc), an update button, and a delete button. What I'm not sure of, is how do I have the update button send the message to the controller for which row to update? I can see a couple way of doing this: Put each row within it's own form tag, then when the update button is clicked, it will submit the values for that row only (there will also be a hidden field with the rowId) and the controller class would take all the post values as parameters to the Update method on the controller. Somehow, have the button be scripted in a way to send back only the values for that row with a POST to the controller. Is there a way of doing this? One thing I am concerned about is if each row has different names for it's controls assigned by ASP.NET (txtName1, txtDesc1, txtName2, txtDesc2), then how will their values get mapped to the correct parameters of the Controller method?

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  • filling colors on a map - PHP

    - by jeremy
    I am trying to determine how to fill colors onto a map - such as the "Risk" board game map. I've done this before with HTML tables, by pulling an HTML color code from a SQL table and then just using it to fill the cell the color I want it. But for a non-square map, I'm not sure where to look. I have created a very simple two color map - its white with black borders. My desired result is having the 'regions' on the map shaded with a color, based on data in a sql table (just like the "fill" button in Paint). This looks like what I need: http://php.net/manual/en/function.imagefilltoborder.php and now.. how to define the borders... At the moment I have tried nothing, because the question was: how do I have PHP fill parts of an image? I have tried making an image in Paint, and then scratching my head wondering how to fill parts of it. Having stumbled upon a link, let me focus this a bit more: It appears that with imagefilltoborder that I can put an image on my server, perhaps one that looks like a black and white version of the RISK map - black borders and white everything else. Some questions: Is it correct that the 'border' variable should use the color of my border (whatever value black is) so that the code can "see" where the border is? Is it correct that I'll just need to figure out X,Y coords to begin the fill? Does this work if I have 10 different spots to fill on the map? Can I use varying colors from code or pulled from SQL to assign different colors to those 10 spots, and use 10 different X,Y coords to get them all?

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  • Merge n files using a C program

    - by Amal
    I am writing a download Accelerator. So I download a file from the webserver into n parts. Now I want to merge the files into 1 single file. So I use the following code. And the file names are in the correct order. But the output file I am getting is different from the original download file. Can you tell me where could the error be ?C int cbd_merge_files(const char** filenames, int n, const char* final_filename) { FILE* fp = fopen(final_filename, "wb"); if (fp == NULL) return 1; char buffer[4097]; for (int i = 0; i < n; ++i) { const char* fname = filenames[i]; FILE* fp_read = fopen(fname, "rb"); if (fp_read == NULL) return 1; int n; while ((n = fread(buffer, sizeof(char), 4096, fp_read))) { int k = fwrite(buffer, sizeof(char), n, fp); if (!k) return 1; } fclose(fp_read); } fclose(fp); return 0; }

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  • C++ compiler unable to find function (namespace related)

    - by CS student
    I'm working in Visual Studio 2008 on a C++ programming assignment. We were supplied with files that define the following namespace hierarchy (the names are just for the sake of this post, I know "namespace XYZ-NAMESPACE" is redundant): (MAIN-NAMESPACE){ a bunch of functions/classes I need to implement... (EXCEPTIONS-NAMESPACE){ a bunch of exceptions } (POINTER-COLLECTIONS-NAMESPACE){ Set and LinkedList classes, plus iterators } } The MAIN-NAMESPACE contents are split between a bunch of files, and for some reason which I don't understand the operator<< for both Set and LinkedList is entirely outside of the MAIN-NAMESPACE (but within Set and LinkedList's header file). Here's the Set version: template<typename T> std::ostream& operator<<(std::ostream& os, const MAIN-NAMESPACE::POINTER-COLLECTIONS-NAMESPACE::Set<T>& set) Now here's the problem: I have the following data structure: Set A Set B Set C double num It's defined to be in a class within MAIN-NAMESPACE. When I create an instance of the class, and try to print one of the sets, it tells me that: error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const MAIN-NAMESPACE::POINTER-COLLECTIONS-NAMESPACE::Set' (or there is no acceptable conversion) However, if I just write a main() function, and create Set A, fill it up, and use the operator- it works. Any idea what is the problem? (note: I tried any combination of using and include I could think of).

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  • String comparison in Python: is vs. ==

    - by Coquelicot
    I noticed a Python script I was writing was acting squirrelly, and traced it to an infinite loop, where the loop condition was "while line is not ''". Running through it in the debugger, it turned out that line was in fact ''. When I changed it to != rather than 'is not', it worked fine. I did some searching, and found this question, the top answer to which seemed to be just what I needed. Except the answer it gave was counter to my experience. Specifically, the answerer wrote: For all built-in Python objects (like strings, lists, dicts, functions, etc.), if x is y, then x==y is also True. I double-checked the type of the variable, and it was in fact of type str (not unicode or something). Is his answer just wrong, or is there something else afoot? Also, is it generally considered better to just use '==' by default, even when comparing int or Boolean values? I've always liked to use 'is' because I find it more aesthetically pleasing and pythonic (which is how I fell into this trap...), but I wonder if it's intended to just be reserved for when you care about finding two objects with the same id.

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  • Give the mount point of a path

    - by Charles Stewart
    The following, very non-robust shell code will give the mount point of $path: (for i in $(df|cut -c 63-99); do case $path in $i*) echo $i;; esac; done) | tail -n 1 Is there a better way to do this? Postscript This script is really awful, but has the redeeming quality that it Works On My Systems. Note that several mount points may be prefixes of $path. Examples On a Linux system: cas@txtproof:~$ path=/sys/block/hda1 cas@txtproof:~$ for i in $(df -a|cut -c 57-99); do case $path in $i*) echo $i;; esac; done| tail -1 /sys On a Mac osx system cas local$ path=/dev/fd/0 cas local$ for i in $(df -a|cut -c 63-99); do case $path in $i*) echo $i;; esac; done| tail -1 /dev Note the need to vary cut's parameters, because of the way df's output differs: indeed, awk is better. Answer It looks like munging tabular output is the only way within the shell, but df /dev/fd/impossible | tail -1 | awk '{ print $NF}' is a big improvement on what I had. Note two differences in semantics: firstly, df $path insists that $path names an existing file, the script I had above doesn't care; secondly, there are no worries about dereferncing symlinks. It's not difficult to write Python code to do the job.

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  • Multithreading using pthread in C++ with shared variables

    - by Saviour Self
    I'm new to threading (and C/C++ for that matter), and I'm attempting to use multiple threads to access shared variables. In the main, I've created a variable char inputarray[100]; Thread 1: This thread will be reading data from stdin in 2 byte bursts, and appending them to the inputarray. (input by feeding a file in) Thread 2: This thread will be reading data 1 byte at a time, performing a calculation, and putting its data into an output array. Thread 3: This thread will be outputting data from the output array in 2 byte bursts. (stdout) I've attempted the input part and got it working by passing a struct, but would like to do it without using a struct, but it has been giving me problems. If I can get input down, I'm sure I'll be able to use a similar strategy to complete output. Any help would be greatly appreciated. Below is a rough template for the input thread. #include <stdio.h> #include <pthread.h> using namespace std; void* input(void* arg) { char reading[3]; fread(reading,1,2,stdin); //append to char inputarray[]..??? } int main() { char inputarray[100]; pthread_t t1; pthread_create(&t1, NULL, &input, &inputarray); void *result; pthread_join(t1,&result); return 0; }

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  • How do I make a HTTP POST request to an url from within a c++ dll?

    - by tjorriemorrie
    Hi, there's an open-source application I need to use. It allows you to use a custom dll. Unfortunately, I can't code c++; i don't like it; it don't want to learn it. I do know PHP very well however, thus you can see that I'll rather do my logic within a PHP application. Thus I'm thinking about posting the data from c++/dll to a url on my localhost. (i have my local server set up, that's not the problem). I need to post a large amount of variables (thus a POST and not GET request required). The return value will only be one (int)variable, either 0, 1 or 2. So I need a c++ function that: 1) will post variables to an url. 2) Wait for, and receive the answer. The data type can be in xml, soap, json, whatever, doesn't matter. Is there anyone that can write a little c++ http function for me? pretty please? ;)

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  • User will input some filter criteria -- how can I turn it into a regular expression for String.match

    - by envinyater
    I have a program where the user will enter a string such as PropertyA = "abc_*" and I need to have the asterisk match any character. In my code, I'm grabbing the property value and replacing PropertyA with the actual value. For instance, it could be abc_123. I also pull out the equality symbol into a variable. It should be able to cover this type of criteria PropertyB = 'cba' PropertyC != '*-this' valueFromHeader is the lefthand side and value is the righthand side. if (equality.equals("=")) { result = valueFromHeader.matches(value); } else if (equality.equals("!=")) { result = !valueFromHeader.matches(value); } EDIT: The existing code had this type of replacement for regular expressions final String ESC = "\\$1"; final String NON_ALPHA = "([^A-Za-z0-9@])"; final String WILD = "*"; final String WILD_RE_TEMP = "@"; final String WILD_RE = ".*"; value = value.replace(WILD, WILD_RE_TEMP); value = value.replaceAll(NON_ALPHA,ESC); value = value.replace(WILD_RE_TEMP, WILD_RE); It doesn't like the underscore here... abcSite_123 != abcSite_123 (evaluates to true) abcSite_123$1.matches("abcSite$1123") It doesn't like the underscore...

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  • Suffix if statement

    - by Aardschok
    I was looking for a way to add a suffix to jointchain in Maya. The jointchain has specific naming so I create a list with the names they need to be. The first chain has "_1" as suffix, result: R_Clavicle_1|R_UpperArm_1|R_UnderArm_1|R_Wrist_1 When I create the second this is the result: R_Clavicle_2|R_UpperArm_1|R_UnderArm_1|R_Wrist_1 The code: DRClavPos = cmds.xform ('DRClavicle', q=True, ws=True, t=True) DRUpArmPos = cmds.xform ('DRUpperArm', q=True, ws=True, t=True) DRUnArmPos = cmds.xform ('DRUnderArm', q=True, ws=True, t=True) DRWristPos = cmds.xform ('DRWrist', q=True, ws=True, t=True), cmds.xform('DRWrist', q=True, os=True, ro=True) suffix = 1 jntsA = cmds.ls(type="joint", long=True) while True: jntname = ["R_Clavicle_"+str(suffix),"R_UpperArm_"+str(suffix),"R_UnderArm_"+str(suffix),"R_Wrist_"+str(suffix)] if jntname not in jntsA: cmds.select (d=True) cmds.joint ( p=(DRClavPos)) cmds.joint ( p=(DRUpArmPos)) cmds.joint ( 'joint1', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[0]) cmds.joint ( p=(DRUnArmPos)) cmds.joint ( 'joint2', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[1]) cmds.joint ( p=(DRWristPos[0])) cmds.joint ( 'joint3', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[2]) cmds.rename ('joint4', jntname[3]) cmds.select ( cl=True) break else: suffix + 1 I tried adding +1 in jntname which resulted in a good second chain but the third chain had "_2" after R_Clavicle_3 The code, in my eyes should work. Can anybody point me in the correct direction :)

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  • Sanitize input before executing at server in php

    - by Interfaith
    I want to let user input two variable, Name and Password in a form. I want to disable any XSS or script insert in the input values. I have the following code in the form method: <form name="form1" method="post" action="checkpw.php"> Your Name: <table> <tr><td><input class="text" name="name" onBlur="capitalize(this);" maxlength=12 type="text" /></td></tr> </table> Password: <table> <tr><td><input class="text" name="passwd" maxlength=8 type="password" /></td></tr> <tr><td align="center"><br/> <input class="text" type="submit" name="submitbt" value="Login" /> </td></tr> </table> and the following checkpw.php: <?php // Clean up the input values $post = filter_input_array(INPUT_POST, array( 'name' => FILTER_SANITIZE_STRING, 'pw' => FILTER_SANITIZE_STRING, )); if (is_null($post) || in_array(null, $post)) { header("location:login.php"); return; // missing fields (or failed filter) } // pw is the password sent from the form $pw=$_POST['passwd']; $name=$_POST['name']; if($pw == 'testpass'){ header("location:index.php"); } else { header("location:wrong.php"); } ?> Is this a secure way to ensure the form is sent to the server and executed ONLY after the input values have been sanitized? Also, the $name value i want to pass it to index.php file. I insert a code in the index.php as follow: <?php echo $name ?> But it's empty. Any idea how to resolve it?

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  • #include - brackets vs quotes in XCode?

    - by Chris Becke
    In MSVC++ #include files are searched for differently depending on whether the file is enclosed in "" or <. The quoted form searches first in the local folder, then in /I specified locations, The angle bracket form avoids the local folder. This means, in MSVC++, its possible to have header files with the same name as runtime and SDK headers. So, for example, I need to wrap up the windows sdk windows.h file to undefine some macro's that cause trouble. With MSVS I can just add a (optional) windows.h file to my project as long as I include it using the quoted form :- // some .cpp file #include "windows.h" // will include my local windows.h file And in my windows.h, I can pull in the real one using the angle bracket form: // my windows.h #include <windows.h> // will load the real one #undef ConflictingSymbol Trying this trick with GCC in XCode didn't work. angle bracket #includes in system header files in fact are finding my header files with similar names in my local folder structure. The MSVC system means its quite safe to have a "String.h" header file in my own folder structre. On XCode this seems to be a major no no. Is there some way to control this search path behaviour in XCode to be more like MSVC's? Or do I just have to avoid naming any of my headers anything that might possibly conflict with a system header. Writing cross platform code and using lots of frameworks means the possibility of incidental conflicts seems large.

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  • Issue changing innodb_log_file_size

    - by savageguy
    I haven't done much tweaking in the past so this might be relatively easy however I am running into issues. This is what I do: Stop MySQL Edit my.cnf (changing innodb_log_file_size) Remove ib_logfile0/1 Start MySQL Starts fine however all InnoDB tables have the .frm file is invalid error, the status shows InnoDB engine is disabled so I obviously go back, remove the change and everything works again. I was able to change every other variable I've tried but I can't seem to find out why InnoDB fails to start even after removing the log files. Am I missing something? Thanks. Edit: Pasting of the log below - looks like it still seems to find the log file even though they are not there? Shutdown: 090813 10:00:14 InnoDB: Starting shutdown... 090813 10:00:17 InnoDB: Shutdown completed; log sequence number 0 739268981 090813 10:00:17 [Note] /usr/sbin/mysqld: Shutdown complete Startup after making the changes: InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes InnoDB: than specified in the .cnf file 0 268435456 bytes! 090813 11:00:18 [Warning] 'user' entry '[email protected]' ignored in --skip-name-resolve mode. 090813 11:00:18 [Note] /usr/sbin/mysqld: ready for connections. Version: '5.0.81-community-log' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Edition (GPL) 090813 11:00:19 [ERROR] /usr/sbin/mysqld: Incorrect information in file: './XXXX/User.frm' 090813 11:00:19 [ERROR] /usr/sbin/mysqld: Incorrect information in file: './XXXX/User.frm' 090813 11:00:19 [ERROR] /usr/sbin/mysqld: Incorrect information in file: './XXXX/User.frm' Its just a spam of the same error until I correct it When it did start after it recreated the log files so it must be looking in the same spot I am.

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  • Memory management of objects returned by methods (iOS / Objective-C)

    - by iOSNewb
    I am learning Objective-C and iOS programming through the terrific iTunesU course posted by Stanford (http://www.stanford.edu/class/cs193p/cgi-bin/drupal/) Assignment 2 is to create a calculator with variable buttons. The chain of commands (e.g. 3+x-y) is stored in a NSMutableArray as "anExpression", and then we sub in random values for x and y based on an NSDictionary to get a solution. This part of the assignment is tripping me up: The final two [methods] “convert” anExpression to/from a property list: + (id)propertyListForExpression:(id)anExpression; + (id)expressionForPropertyList:(id)propertyList; You’ll remember from lecture that a property list is just any combination of NSArray, NSDictionary, NSString, NSNumber, etc., so why do we even need this method since anExpression is already a property list? (Since the expressions we build are NSMutableArrays that contain only NSString and NSNumber objects, they are, indeed, already property lists.) Well, because the caller of our API has no idea that anExpression is a property list. That’s an internal implementation detail we have chosen not to expose to callers. Even so, you may think, the implementation of these two methods is easy because anExpression is already a property list so we can just return the argument right back, right? Well, yes and no. The memory management on this one is a bit tricky. We’ll leave it up to you to figure out. Give it your best shot. Obviously, I am missing something with respect to memory management because I don't see why I can't just return the passed arguments right back. Thanks in advance for any answers!

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  • Why does my simple event handling example not work?

    - by njreed
    I am trying to make a simple event handler. (Note, I'm not trying to implement a full-blown publish/subscribe model; I'm just interested in why my example doesn't work as I think it should) var myObj = (function () { var private = "X"; function triggerEvent(eventName) { if (this[eventName]) { this[eventName](); } } // Setter / Getter function getProp() { return private; } function setProp(value) { private = value; triggerEvent("onPropChange"); } // Public API return { // Events "onPropChange": null, // Fires when prop value is changed // Methods "getProp": getProp, "setProp": setProp }; })(); // Now set event handler myObj.onPropChange = function () { alert("You changed the property!"); }; myObj.setProp("Z"); // --> Nothing happens. Wrong // Why doesn't my alert show? I set the onPropChange property of my object to a simpler handler function but it is not being fired. I have debugged this and it seems that in triggerEvent the variable this is referencing the global window object. I thought it should reference myObj (which is what I need). Can someone explain the error in my thinking and how I correct this? Help much appreciated. jsFiddle here

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  • php array split

    - by Rahul Mehta
    I am passing the space separated value to in input and split this in operation and make an array. givecard 442 ashutosh2 Y But i want to pass the message in this string and want to split as complete message in operation or output. givecard 442 ashutosh2 Y hi how are you if i split this line than i get the result is Array ( [0] => givecard [1] => 442 [2] => ashutosh2 [3] => Y [4] => hi [5] => how [6] => are [7] => you ) But i want like this Array ( [0] => givecard [1] => 442 [2] => ashutosh2 [3] => Y [4] => hi how are you ) as here hi how are you i want to extract as complete one message in a variable . How can i achieve this

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  • Insert not working

    - by user1642318
    I've searched evreywhere and tried all suggestions but still no luck when running the following code. Note that some code is commented out. Thats just me trying different things. SqlConnection connection = new SqlConnection("Data Source=URB900-PC\SQLEXPRESS;Initial Catalog=usersSQL;Integrated Security=True"); string password = PasswordTextBox.Text; string email = EmailTextBox.Text; string firstname = FirstNameTextBox.Text; string lastname = SurnameTextBox.Text; //command.Parameters.AddWithValue("@UserName", username); //command.Parameters.AddWithValue("@Password", password); //command.Parameters.AddWithValue("@Email", email); //command.Parameters.AddWithValue("@FirstName", firstname); //command.Parameters.AddWithValue("@LastName", lastname); command.Parameters.Add("@UserName", SqlDbType.VarChar); command.Parameters["@UserName"].Value = username; command.Parameters.Add("@Password", SqlDbType.VarChar); command.Parameters["@Password"].Value = password; command.Parameters.Add("@Email", SqlDbType.VarChar); command.Parameters["@Email"].Value = email; command.Parameters.Add("@FirstName", SqlDbType.VarChar); command.Parameters["@FirstName"].Value = firstname; command.Parameters.Add("@LasttName", SqlDbType.VarChar); command.Parameters["@LasttName"].Value = lastname; SqlCommand command2 = new SqlCommand("INSERT INTO users (UserName, Password, UserEmail, FirstName, LastName)" + "values (@UserName, @Password, @Email, @FirstName, @LastName)", connection); connection.Open(); command2.ExecuteNonQuery(); //command2.ExecuteScalar(); connection.Close(); When I run this, fill in the textboxes and hit the button I get...... Must declare the scalar variable "@UserName". Any help would be greatly appreciated. Thanks.

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  • How do I use the Enum value from a class in another part of code?

    - by ChiggenWingz
    Coming from a C# background from a night course at a local college, I've sort of started my way in C++. Having a lot pain getting use to the syntax. I'm also still very green when it comes to coding techniques. From my WinMain function, I want to be able to access a variable which is using an enum I declared in another class. (inside core.h) class Core { public: enum GAME_MODE { INIT, MENUS, GAMEPLAY }; GAME_MODE gameMode; Core(); ~Core(); ...OtherFunctions(); }; (inside main.cpp) Core core; int WINAPI WinMain(...) { ... startup code here... core.gameMode = Core.GAME_MODE.INIT; ...etc... } Basically I want to set that gameMode to the enum value of Init or something like that from my WinMain function. I want to also be able to read it from other areas. I get the error... expected primary-expression before '.' token If I try to use core.gameMode = Core::GAME_MODE.INIT;, then I get the same error. I'm not fussed about best practices, as I'm just trying to get the basic understanding of passing around variables in C++ between files. I'll be making sure variables are protected and neatly tucked away later on once I am use to the flexibility of the syntax. If I remember correctly, C# allowed me to use Enums from other classes, and all I had to do was something like Core.ENUMNAME.ENUMVALUE. I hope what I'm wanting to do is clear :\ As I have no idea what a lot of the correct terminology is.

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  • How can I store this kind of graph in neo4j for fast traversal?

    - by James
    This is a graph whose nodes exist in many connected components at once because a node's relationships are a collection of edge groups such that only one edge per edge group can be present at once. I need to be able to find all of the connected components that a node exists in. What would be the best way to store this graph in neo4j to quickly find all of the connected components that a node exists in? Is there a way to use the built in traversals to do this? Also: is there a name for this kind of graph? I'd appreciate any help/ideas. Update: Sorry for not being clear. All nodes are of the same type. Nodes have a variable number of edge groups. Exactly one edge from each edge group needs to be chosen for a particular connected component. I'm going to try to explain through example: Node x1 is related to: (x2 or x3 or x4) AND (x5 or x6) AND (x7) Node x2 is related to: (x8) AND (x9 or x10) So x1's first edge group is (x2, x3, x4), its second edge group is (x5, x6), and its third edge group is (x7). So here are a few connected components that x1 exists in: CC1: x1 is related to: x2, x5, x7 x2 is related to: x8 x9 CC2: x1 is related to: x2, x6, x7 x2 is related to: x8, x9 CC3: x1 is related to: x3, x5, x7 CC4: x1 is related to: x3, x6, x7 etc. I'm grateful for your help in this.

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  • Java: Tracking a user login session - Session EJBs vs HTTPSession

    - by bguiz
    If I want to keep track of a conversational state with each client using my web application, which is the better alternative - a Session Bean or a HTTP Session - to use? Using HTTP Session: //request is a variable of the class javax.servlet.http.HttpServletRequest //UserState is a POJO HttpSession session = request.getSession(true); UserState state = (UserState)(session.getAttribute("UserState")); if (state == null) { //create default value .. } String uid = state.getUID(); //now do things with the user id Using Session EJB: In the implementation of ServletContextListener registered as a Web Application Listener in WEB-INF/web.xml: //UserState NOT a POJO this this time, it is //the interface of the UserStateBean Stateful Session EJB @EJB private UserState userStateBean; public void contextInitialized(ServletContextEvent sce) { ServletContext servletContext = sce.getServletContext(); servletContext.setAttribute("UserState", userStateBean); ... In a JSP: public void jspInit() { UserState state = (UserState)(getServletContext().getAttribute("UserState")); ... } Elsewhere in the body of the same JSP: String uid = state.getUID(); //now do things with the user id It seems to me that the they are almost the same, with the main difference being that the UserState instance is being transported in the HttpRequest.HttpSession in the former, and in a ServletContext in the case of the latter. Which of the two methods is more robust, and why?

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  • Conversion failed when converting datetime from character string

    - by salvationishere
    I am developing a C# VS 2008 / SQL Server 2005 Express website application. I have tried some of the fixes for this problem but my call stack differs from others. And these fixes did not fix my problem. What steps can I take to troubleshoot this? Here is my error: System.Data.SqlClient.SqlException was caught Message="Conversion failed when converting datetime from character string." Source=".Net SqlClient Data Provider" ErrorCode=-2146232060 LineNumber=10 Number=241 Procedure="AppendDataCT" Server="\\\\.\\pipe\\772EF469-84F1-43\\tsql\\query" State=1 StackTrace: at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at ADONET_namespace.ADONET_methods.AppendDataCT(DataTable dt, Dictionary`2 dic) in c:\Documents and Settings\Admin\My Documents\Visual Studio 2008\WebSites\Jerry\App_Code\ADONET methods.cs:line 102 And here is the related code. When I debugged this code, "dic" only looped through the 3 column names, but did not look into row values which are stored in "dt", the Data Table. public static string AppendDataCT(DataTable dt, Dictionary<string, string> dic) { if (dic.Count != 3) throw new ArgumentOutOfRangeException("dic can only have 3 parameters"); string connString = ConfigurationManager.ConnectionStrings["AW3_string"].ConnectionString; string errorMsg; try { using (SqlConnection conn2 = new SqlConnection(connString)) { using (SqlCommand cmd = conn2.CreateCommand()) { cmd.CommandText = "dbo.AppendDataCT"; cmd.CommandType = CommandType.StoredProcedure; cmd.Connection = conn2; foreach (string s in dic.Keys) { SqlParameter p = cmd.Parameters.AddWithValue(s, dic[s]); p.SqlDbType = SqlDbType.VarChar; } conn2.Open(); cmd.ExecuteNonQuery(); conn2.Close(); errorMsg = "The Person.ContactType table was successfully updated!"; } } }

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  • different thread accessing MemoryStream

    - by Wayne
    There's a bit of code which writes data to a MemoryStream object directly into it's data buffer by calling GetBuffer(). It also uses and updates the Position and SetLength() properties appropriately. This code works purposes 99.9999% of the time. Literally. Only every so many 100,000's of iterations it will barf. The specific problem is that the memory.Position property suddenly returns zero instead of the appropriate value. However, code was added that checks for the 0 and throws an exception which include log of the MemoryStream properties like Position and Length in a separate method. Those return the correct value. Further addition shows that when this rare condition occurs, the memory.Position only has zero inside this particular method. Okay. Obviously, this must be a threading issue. But this code is well locked. However, the nature of this software is that it's organized by "tasks" with a scheduler and so any one of several actual O/S thread may run this code at any give time--but never more than one at a time. So it's my guess that ordinarily it so happens that the same thread keeps getting used for this method and then on a rare occasion a different thread get used. Then due to compiler optimizations, the different thread never gets the correct value. It gets a "stale" value. Ordinarily in a situation like this I would apply a "volatile" keyword to the variable in question. But that (those) variables are inside the MemoryStream object. Does anyone have any other idea? Or does this mean we have to implement our own MemoryStream object? (Just like we end up having to do with practically every collection in .NET?) It's a shame to have such an awesome platform as .NET and have virtually the entire system useless as-is for seriously parallelized applications. If I'm wrong or you have other ideas, please advise. Sincerely, Wayne

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  • How can I build a generic dataset-handling Perl library?

    - by Pep.
    Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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  • sort files by date in PHP

    - by sasori
    hi, I currently have an index.php file which allows me to output the list of files inside the same directory, the output shows the names then I used filemtime() function to show the date when the file was modified. my problem now is, how will I sort the output to show the latest modified file ?, I've been thinking for awhile how to do this. if only I am doing it with mysql interaction there will be no problem at all. please show me an example how to sort and output the list of files starting from the latest modified one. this is what i have for now if ($handle = opendir('.')) { while (false !== ($file = readdir($handle))) { if ($file != "." && $file != "..") { $lastModified = date('F d Y, H:i:s',filemtime($file)); if(strlen($file)-strpos($file,".swf")== 4){ echo "<tr><td><input type=\"checkbox\" name=\"box[]\"></td><td><a href=\"$file\" target=\"_blank\">$file</a></td><td>$lastModified</td></tr>"; } } } closedir($handle); }

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