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  • Why does adding Crossover to my Genetic Algorithm gives me worse results?

    - by MahlerFive
    I have implemented a Genetic Algorithm to solve the Traveling Salesman Problem (TSP). When I use only mutation, I find better solutions than when I add in crossover. I know that normal crossover methods do not work for TSP, so I implemented both the Ordered Crossover and the PMX Crossover methods, and both suffer from bad results. Here are the other parameters I'm using: Mutation: Single Swap Mutation or Inverted Subsequence Mutation (as described by Tiendil here) with mutation rates tested between 1% and 25%. Selection: Roulette Wheel Selection Fitness function: 1 / distance of tour Population size: Tested 100, 200, 500, I also run the GA 5 times so that I have a variety of starting populations. Stop Condition: 2500 generations With the same dataset of 26 points, I usually get results of about 500-600 distance using purely mutation with high mutation rates. When adding crossover my results are usually in the 800 distance range. The other confusing thing is that I have also implemented a very simple Hill-Climbing algorithm to solve the problem and when I run that 1000 times (faster than running the GA 5 times) I get results around 410-450 distance, and I would expect to get better results using a GA. Any ideas as to why my GA performing worse when I add crossover? And why is it performing much worse than a simple Hill-Climb algorithm which should get stuck on local maxima as it has no way of exploring once it finds a local max?

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  • Most efficient way to check for DBNull and then assign to a variable?

    - by ilitirit
    This question comes up occasionally but I haven't seen a satisfactory answer. A typical pattern is (row is a DataRow): if (row["value"] != DBNull.Value) { someObject.Member = row["value"]; } My first question is which is more efficient (I've flipped the condition): row["value"] == DBNull.Value; // Or row["value"] is DBNull; // Or row["value"].GetType() == typeof(DBNull) // Or... any suggestions? This indicates that .GetType() should be faster, but maybe the compiler knows a few tricks I don't? Second question, is it worth caching the value of row["value"] or does the compiler optimize the indexer away anyway? eg. object valueHolder; if (DBNull.Value == (valueHolder = row["value"])) {} Disclaimers: row["value"] exists. I don't know the column index of the column (hence the column name lookup) I'm asking specifically about checking for DBNull and then assignment (not about premature optimization etc). Edit: I benchmarked a few scenarios (time in seconds, 10000000 trials): row["value"] == DBNull.Value: 00:00:01.5478995 row["value"] is DBNull: 00:00:01.6306578 row["value"].GetType() == typeof(DBNull): 00:00:02.0138757 Object.ReferenceEquals has the same performance as "==" The most interesting result? If you mismatch the name of the column by case (eg. "Value" instead of "value", it takes roughly ten times longer (for a string): row["Value"] == DBNull.Value: 00:00:12.2792374 The moral of the story seems to be that if you can't look up a column by it's index, then ensure that the column name you feed to the indexer matches the DataColumn's name exactly. Caching the value also appears to be nearly twice as fast: No Caching: 00:00:03.0996622 With Caching: 00:00:01.5659920 So the most efficient method seems to be: object temp; string variable; if (DBNull.Value != (temp = row["value"]) { variable = temp.ToString(); } This was a good learning experience.

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  • Can I use a *.tag from another *.tag file in the same /WEB-INF/tags folder?

    - by Ytsejammer
    Hello, I am trying to refactor my JSP code so that a small conditional test condition gets reused through a *.tag file. There are some big parts of my UI that depend on the value of a two-state property of an object present in the request. Let's say the property is 'gender' and the object is of type Person. Like I said, I would like to simplify & centralize the test on the gender property using a tag. For this purpose, I created two tag files: /WEB-INF/tags/if-male.tag /WEB-INF/tags/if-female.tag Now, I have another tiny spot that gets repeated in all over my application; let's say is the salutation to my site user. With this idea, I created a tag like this: /WEB-INF/tags/salutation.tag As you can imagine, I am trying to use the if-male/if-female test within the salutation.tag file to output 'Mrs.' or 'Mr.' like this: <%@ tag body-content="empty" %> <%@ taglib prefix="g" uri="/WEB-INF/tags" %> <g:if-male> Mr. </g:if-male> <g:if-female> Mrs. </g:if-female> Is the use of the if-male/if-female tags legal within the salutation.tag file? I have tried with such arrangement, but it looks like the JDeveloper 10.1.3.4 compiler gets confused and cannot deal with the salutation.tag tag invoking the other two tags in the same 'library' (folder under /WEB-INF/tags). The reference works perfectly in Jetty 6 and it looks like it works as well if I deploy the application to OC4J directly without relying on JDeveloper to pre-compile all my JSPs. I hope someone can shed some light on this. Thanks, YJ

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  • When do you tag your software project?

    - by WilhelmTell of Purple-Magenta
    I realize there are various kinds of software projects: commercial (for John Doe) industrial (for Mr. Montgomery Burns) successful open-source (with audience larger than, say, 10 people) personal projects (with audience size in the vicinity of 1). each of which release a new version of their product on difference conditions. I'm particularly interested in the case of personal projects and open-source projects. When, or under what conditions, do you make a new release of any kind? Do you subscribe to a fixed recurring deadline such as every two weeks? Do you commit to a release of at least 10 minor fixes, or one major fix? Do you combine the two conditions such as at least one condition must hold, or both must hold? I reckon this is a subjective question. I ask this question in light of searching for tricks to keep my projects alive and kicking. Sometimes my projects are active but look as if they aren't because I don't have the confidence to make a release or a tag of any sort for a long time -- in the order of months.

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  • Which linear programming package should I use for high numbers of constraints and "warm starts"

    - by davidsd
    I have a "continuous" linear programming problem that involves maximizing a linear function over a curved convex space. In typical LP problems, the convex space is a polytope, but in this case the convex space is piecewise curved -- that is, it has faces, edges, and vertices, but the edges aren't straight and the faces aren't flat. Instead of being specified by a finite number of linear inequalities, I have a continuously infinite number. I'm currently dealing with this by approximating the surface by a polytope, which means discretizing the continuously infinite constraints into a very large finite number of constraints. I'm also in the situation where I'd like to know how the answer changes under small perturbations to the underlying problem. Thus, I'd like to be able to supply an initial condition to the solver based on a nearby solution. I believe this capability is called a "warm start." Can someone help me distinguish between the various LP packages out there? I'm not so concerned with user-friendliness as speed (for large numbers of constraints), high-precision arithmetic, and warm starts. Thanks!

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  • Messaging pattern question

    - by Al Bundy
    Process A is calculating values for objects a1, a2, a3 etc. and is sending results to the middleware queue (RabbitMQ). Consumers read the queue and process these results further. Periodically process A has to send a snapshot of these values, so consumers could do some other calculations. Values for these objects might change independently. The queue might look like this a1, a1, a2, a1, a2, a2, a3... Consumers process each item in the queue. The snapshot has to contain all objects and consumers will process this message for all objects in one go. So the requirement is to have a queue like this: a1, a1, a3, a2, a2, [snapshot, a1, a2, a3], a3, a1 ... The problem is that these items are of different types: one type for objects like a1, a2 and other for a snapshot. This means that they should be processed in a diferent queues, but in that case there is a race condition: consumers might process objects before processing a snapshot. Is there any pattern to solve this (quite common) problem? We are using RabbitMQ for message queueing.

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  • Using Rails Helper Methods within ActionRecord Queries?

    - by Pygmalion
    I have a table of events (in a sqlite3 database for what it's worth) with a column called "when" that contains a timestamp detailing precisely when the event that particular row denotes is set to occur. Right now, I have @events = Event.find(:all) in my controller and I am using template helper methods to calculate where to place each event on my display page based on the day of the week it occurs on. For example: <% if(event.when.wday == 6) %> # DO SOMETHING <% end %> I want to abstract this logic to the controller however. My idea was to do the following: @thursday_events = Event.find(:all, :conditions => ["when.wday=4"]) Obviously (I guess?) this didn't work. Throwing the error "SQLite3::SQLException: near "when": syntax error: SELECT * FROM "events" WHERE (when.wday=4)". I'm assuming this is because I tried to use a helper method within a find condition but I don't know a better way to do this. Any advice? Thanks!

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  • Applying the Hibernate filter attribute to a Bag with a many-to-many relationship

    - by David P
    Consider the following Hibernate mapping file: <hibernate-mapping ...> <class name="ContentPackage" table="contentPackages"> <id name="Id" column="id" type="int"><generator class="native" /></id> ... <bag name="Clips" table="contentAudVidLinks"> <key column="fk_contentPackageId"></key> <many-to-many class="Clip" column="fk_AudVidId"></many-to-many> <filter name="effectiveDate" condition=":asOfDate BETWEEN startDate and endDate" /> </bag> </class> </hibernate-mapping> When I run the following command: _session.EnableFilter("effectiveDate").SetParameter("asOfDate", DateTime.Today); IList<ContentPackage> items = _session.CreateCriteria(typeof(ContentPackage)) .Add(Restrictions.Eq("Id", id)) .List<ContentPackage>(); The resulting SQL has the WHERE clause on the intermediate mapping table (contentAudVidLinks), rather than the "Clips" table even though I have added the filter attribute to the Bag of Clips. What am I doing wrong?

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  • The algorithm used to generate recommendations in Google News?

    - by Siddhant
    Hi everyone. I'm study recommendation engines, and I went through the paper that defines how Google News generates recommendations to users for news items which might be of their interest, based on collaborative filtering. One interesting technique that they mention is Minhashing. I went through what it does, but I'm pretty sure that what I have is a fuzzy idea and there is a strong chance that I'm wrong. The following is what I could make out of it :- Collect a set of all news items. Define a hash function for a user. This hash function returns the index of the first item from the news items which this user viewed, in the list of all news items. Collect, say "n" number of such values, and represent a user with this list of values. Based on the similarity count between these lists, we can calculate the similarity between users as the number of common items. This reduces the number of comparisons a lot. Based on these similarity measures, group users into different clusters. This is just what I think it might be. In Step 2, instead of defining a constant hash function, it might be possible that we vary the hash function in a way that it returns the index of a different element. So one hash function could return the index of the first element from the user's list, another hash function could return the index of the second element from the user's list, and so on. So the nature of the hash function satisfying the minwise independent permutations condition, this does sound like a possible approach. Could anyone please confirm if what I think is correct? Or the minhashing portion of Google News Recommendations, functions in some other way? I'm new to internal implementations of recommendations. Any help is appreciated a lot. Thanks!

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  • strategy for choosing proper object and proper method

    - by zerkms
    in the code below at first if statements block (there will be more than just "worker" condition, joined with else if) i select proper filter_object. After this in the same conditional block i select what filter should be applied by filter object. This code is silly. public class Filter { public static List<data.Issue> fetch(string type, string filter) { Filter_Base filter_object = new Filter_Base(filter); if (type == "worker") { filter_object = new Filter_Worker(filter); } else if (type == "dispatcher") { filter_object = new Filter_Dispatcher(filter); } List<data.Issue> result = new List<data.Issue>(); if (filter == "new") { result = filter_object.new_issues(); } else if (filter == "ended") { result = filter_object.ended_issues(); } return result; } } public class Filter_Base { protected string _filter; public Filter_Base(string filter) { _filter = filter; } public virtual List<data.Issue> new_issues() { return new List<data.Issue>(); } public virtual List<data.Issue> ended_issues() { return new List<data.Issue>(); } } public class Filter_Worker : Filter_Base { public Filter_Worker(string filter) : base(filter) { } public override List<data.Issue> new_issues() { return (from i in data.db.GetInstance().Issues where (new int[] { 4, 5 }).Contains(i.RequestStatusId) select i).Take(10).ToList(); } } public class Filter_Dispatcher : Filter_Base { public Filter_Dispatcher(string filter) : base(filter) { } } it will be used in some kind of: Filter.fetch("worker", "new"); this code means, that for user that belongs to role "worker" only "new" issues will be fetched (this is some kind of small and simple CRM). Or another: Filter.fetch("dispatcher", "ended"); // here we get finished issues for dispatcher role Any proposals on how to improve it?

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  • How to MakeTable ReadOnly including contents like images

    - by GustlyWind
    I have a table which has two text boxes and a image beside it to click and open a popup. In read-only mode based on condition I am able to make text boxes read-only but images are not becoming read-only.One solution I had is the anchor tag associated with image calls for JavaScript where I can check for a dummy click when it is in read-only mode. The problem here is the function is common and effects everywhere. So is there a way to make the entire table read-only so that no extra workaround needs to done. Edited for code <table> <tr> <td class="lightbg" colspan='4'>&nbsp; Expires:<input type="TEXT" value="" id="element1" name="expireDate" size="10" maxlength="20" class="" onChange="javascript:validateDateEntry('element1',true);;"> Period:<input type="TEXT" value="" id="element2" name="refershDate" size="10" maxlength="20" class="" onChange="javascript:validateDateEntry('element2',true);;"> &nbsp; <a href="javascript:doCalendar('element1');"> <img src="/PWM/images/images_2006/calendarbtn.gif" border="0" alt="Click to select date from calendar" align="absmiddle"> </a> </td> </tr> <tr> <td colspan='4'><b>*</b>Times are in the WFM Server's Time Zone.</td></tr> </table> Thanks

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  • How do I get the collection of Model State Errors in ASP.NET MVC?

    - by Ryan Montgomery
    How do I get the collection of errors in a view? I don't want to use the Html Helper Validation Summary or Validation Message. Instead I want to check for errors and if any display them in specific format. Also on the input controls I want to check for a specific property error and add a class to the input. P.S. I'm using the Spark View Engine but the idea should be the same. So I figured I could do something like... <if condition="${ModelState.Errors.Count > 0}"> DispalyErrorSummary() </if> ....and also... <input type="text" value="${Model.Name}" class="?{ModelState.Errors["Name"] != string.empty} error" /> .... Or something like that. UPDATE My final solution looked like this: <input type="text" value="${ViewData.Model.Name}" class="text error?{!ViewData.ModelState.IsValid && ViewData.ModelState["Name"].Errors.Count() > 0}" id="Name" name="Name" /> This only adds the error css class if this property has an error.

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  • Binding a date string parameter in an MS Access PDO query

    - by harryg
    I've made a PDO database class which I use to run queries on an MS Access database. When querying using a date condition, as is common in SQL, dates are passed as a string. Access usually expects the date to be surrounded in hashes however. E.g. SELECT transactions.amount FROM transactions WHERE transactions.date = #2013-05-25#; If I where to run this query using PDO I might do the following. //instatiate pdo connection etc... resulting in a $db object $stmt = $db->prepare('SELECT transactions.amount FROM transactions WHERE transactions.date = #:mydate#;'); //prepare the query $stmt->bindValue('mydate', '2013-05-25', PDO::PARAM_STR); //bind the date as a string $stmt->execute(); //run it $result = $stmt->fetch(); //get the results As far as my understanding goes the statement that results from the above would look like this as binding a string results in it being surrounded by quotes: SELECT transactions.amount FROM transactions WHERE transactions.date = #'2013-05-25'#; This causes an error and prevents the statement from running. What's the best way to bind a date string in PDO without causing this error? I'm currently resorting to sprintf-ing the string which I'm sure is bad practise. Edit: if I pass the hash-surrounded date then I still get the error as below: Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[22018]: Invalid character value for cast specification: -3030 [Microsoft][ODBC Microsoft Access Driver] Data type mismatch in criteria expression. (SQLExecute[-3030] at ext\pdo_odbc\odbc_stmt.c:254)' in C:\xampp\htdocs\ips\php\classes.php:49 Stack trace: #0 C:\xampp\htdocs\ips\php\classes.php(49): PDOStatement-execute() #1 C:\xampp\htdocs\ips\php\classes.php(52): database-execute() #2 C:\xampp\htdocs\ips\try2.php(12): database-resultset() #3 {main} thrown in C:\xampp\htdocs\ips\php\classes.php on line 49

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  • sql query - how to apply limit within group by

    - by Raj
    hey guys assuming i have a table named t1 with following fields: ROWID, CID, PID, Score, SortKey it has the following data: 1, C1, P1, 10, 1 2, C1, P2, 20, 2 3, C1, P3, 30, 3 4, C2, P4, 20, 3 5, C2, P5, 30, 2 6, C3, P6, 10, 1 7, C3, P7, 20, 2 what query do i write so that it applies group by on CID, but instead of returning me 1 single result per group, it returns me a max of 2 results per group. also where condition is score = 20 and i want the results ordered by CID and SortKey. If I had to run my query on above data, i would expect the following result: RESULTS FOR C1 - note: ROWID 1 is not considered as its score < 20 C1, P2, 20, 2 C1, P3, 30, 3 RESULTS FOR C2 - note: ROWID 5 appears before ROWID 4 as ROWID 5 has lesser value SortKey C2, P5, 30, 2 C2, P4, 20, 3 RESULTS FOR C3 - note: ROWID 6 does not appear as its score is less than 20 so only 1 record returned here C3, P7, 20, 2 IN SHORT, I WANT A LIMIT WITHIN A GROUP BY. I want the simplest solution and want to avoid temp tables. sub queries are fine. also note i am using sqlite for this

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  • Replace apostrophe in json string with empty string

    - by user572844
    Hi, I have problem with deserialization of json string, because string is bad format. For example json object consist string property statusMessage with value "Hello "dog" ". The correct format should be "Hello \" dog \" " . I would like remove apostrophes from this property. Something Like this. "Hello "dog" ". - "Hello dog ". Here is it original json string which I work. "{\"jancl\":{\"idUser\":18438201,\"nick\":\"JANCl\",\"photo\":\"1\",\"sex\":1,\"photoAlbums\":1,\"videoAlbums\":0,\"sefNick\":\"jancl\",\"profilPercent\":75,\"emphasis\":false,\"age\":\"-\",\"isBlocked\":false,\"PHOTO\":{\"normal\":\"http://u.aimg.sk/fotky/1843/82/n_18438201.jpg?v=1\",\"medium\":\"http://u.aimg.sk/fotky/1843/82/m_18438201.jpg?v=1\",\"24x24\":\"http://u.aimg.sk/fotky/1843/82/s_18438201.jpg?v=1\"},\"PLUS\":{\"active\":false,\"activeTo\":\"0000-00-00\"},\"LOCATION\":{\"idRegion\":\"6\",\"regionName\":\"Trenciansky kraj\",\"idCity\":\"138\",\"cityName\":\"Trencianske Teplice\"},\"STATUS\":{\"isLoged\":true,\"isChating\":false,\"idChat\":0,\"roomName\":\"\",\"lastLogin\":1294925369},\"PROJECT_STATUS\":{\"photoAlbums\":1,\"photoAlbumsFavs\":0,\"videoAlbums\":0,\"videoAlbumsFavs\":0,\"videoAlbumsExts\":0,\"blogPosts\":0,\"emailNew\":0,\"postaNew\":0,\"clubInvitations\":0,\"dashboardItems\":1},\"STATUS_MESSAGE\":{\"statusMessage\":\"\"Status\"\",\"addTime\":\"1294872330\"},\"isFriend\":false,\"isIamFriend\":false}}" Problem is here, json string consist this object: "STATUS_MESSAGE": {"statusMessage":" "some "bad" value" ", "addTime" :"1294872330"} Condition of string which I want modified: string start with "statusMessage":" string can has any *lenght from 0 -N * string end with ", "addTime So I try write pattern for string which start with "statusMessage":", has any lenght and is ended with ", "addTime. Here is it: const string pattern = " \" statusMessage \" : \" .*? \",\"addTime\" "; var regex = new Regex(pattern, RegexOptions.IgnoreCase); //here i would replace " with empty string string result = regex.Replace(jsonString, match => ???); But I think pattern is wrong, also I don’t know how replace apostrophe with empty string (remove apostrophne). My goal is : "statusMessage":" "some "bad" value" to "statusMessage":" "some bad value" Thank for advice

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  • SQL: Need help with query construction.

    - by Geeknidas
    Hi Guys, I am relatively new with sql and I need some help with some basic query construction. Problem: To retrieve the number of orders and the customer id from a table based on a set of parameters. I want to write a query to figure out the number of orders under each customer (Column: Customerid) along with the CustomerID where the number of orders should be greater or equal to 10 and the status of the order should be Active. Moreover, I also want to know the first transaction date of an order belonging to each customerid. Table Description: product_orders Orderid CustomerId Transaction_date Status ------- ---------- ---------------- ------- 1 23 2-2-10 Active 2 22 2-3-10 Active 3 23 2-3-10 Deleted 4 23 2-3-10 Active Query that I have written: select count(*), customerid from product_orders where status = 'Active' GROUP BY customerid ORDER BY customerid; The above statement gives me the sum of all order under a customer id but does not fulfil the condition of atleast 10 orders. I donot know how to display the first transaction date along with the order under a customerid (status: could be active or delelted doesn't matter) Ideal solutions should look like: Total Orders CustomerID Transaction Date (the first transaction date) ------------ ---------- ---------------- 11 23 1-2-10 Thanks in advance. I hope you guys would be kind enough to stop by and help me out. Cheers, Leonidas

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  • write to fifo/pipe from shell, with timeout

    - by Tim
    I have a pair of shell programs that talk over a named pipe. The reader creates the pipe when it starts, and removes it when it exits. Sometimes, the writer will attempt to write to the pipe between the time that the reader stops reading and the time that it removes the pipe. reader: while condition; do read data <$PIPE; do_stuff; done writer: echo $data >>$PIPE reader: rm $PIPE when this happens, the writer will hang forever trying to open the pipe for writing. Is there a clean way to give it a timeout, so that it won't stay hung until killed manually? I know I can do #!/bin/sh # timed_write <timeout> <file> <args> # like "echo <args> >> <file>" with a timeout TIMEOUT=$1 shift; FILENAME=$1 shift; PID=$$ (X=0; # don't do "sleep $TIMEOUT", the "kill %1" doesn't kill the sleep while [ "$X" -lt "$TIMEOUT" ]; do sleep 1; X=$(expr $X + 1); done; kill $PID) & echo "$@" >>$FILENAME kill %1 but this is kind of icky. Is there a shell builtin or command to do this more cleanly (without breaking out the C compiler)?

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  • Help passing reference to class subroutine in Perl.

    - by stephenmm
    I am trying to pass a routine to another subroutine within a Perl module. But when I pass the sub reference the passed in ref no longer has the object data. Maybe its not possible to do it this way. The line I have a question about is the "unless" lines below: sub get_flag_end { my $self = shift; return ( -e "$self->{file}" ); } sub wait_for_end { my $self = shift; my $timeout = shift; my $poll_interval = shift; # Is it even possible to pass the oject subroutine and retain the objects data? #unless ( $self->timeout( $timeout, $poll_interval, $self->get_flag_end ) ) { # does not work unless ( $self->timeout( $timeout, $poll_interval, \&get_flag_end ) ) { # call happens but members are empty die "!!!ERROR!!! Timed out while waiting for wait_for_end: timeout=$timeout, poll_interval=$poll_interval \n"; } } sub timeout { my $self = shift; my $timeout = shift; my $poll_interval = shift; my $test_condition = shift; until ($test_condition->() || $timeout <= 0) { $timeout -= $poll_interval; sleep $poll_interval; } return $timeout > 0; # condition was met before timeout } I know that I could change the "get_flag_end" routine to take the value as an argument to the subroutine but what if there was a bunch of stuff done in "get_flag_end" and I needed more members from the object. I simplified the code a bit to make it a little easier to follow.

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  • UI Automation Button Style Enabled

    - by Victor Gaspar
    Hi, I'm evaluating UI Automation for UI testing for that I have a WPF application with the following button defined: <Button Style="{DynamicResource ButtonStyle}" x:Name="MyBtn"/> when I need to visually disable the button I just change the style so the user is aware that the button is disabled (the colour changed) but still the button is internally enabled so I can still launch the OnClick event in order to show a message when the user clicks on a "disabled" button. Now the problem is that I don't know how to check from UI Automation the Style that its currently applied i.e. if the button is disabled or enabled. Do you know how can I do that? In a normal situation I should do something like that: Automation.Condition cEBtn = new PropertyCondition(AutomationElement.AutomationIdProperty, "MyBtn"); AutomationElement mybtnElement = appRegraceElement.FindFirst(TreeScope.Children, cEBtn); bool disMyBtn = (bool)mybtnElement .GetCurrentPropertyValue(AutomationElement.IsEnabledProperty); but in my case the button is always enabled therefore I need to check the Style applied to the button. Thank you very much. Best regards

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  • verilog / systemverilog -- What is the behavior of blocking statements across two always blocks?

    - by miles.sherman
    I am wondering about the behavior of the below code. There are two always blocks, one is combinational to calculate the next_state signal, the other is sequential which will perform some logic and determine whether or not to shutdown the system. It does this by setting the shutdown_now signal high and then calling state <= next_state. My question is if the conditions become true that the shutdown_now signal is set (during clock cycle n) in a blocking manner before the state <= next_state line, will the state during clock cycle n+1 be SHUTDOWN or RUNNING? In other words, does the shutdown_now = 1'b1 line block across both state machines since the state signal is dependent on it through the next_state determination? enum {IDLE, RUNNING, SHUTDOWN} state, next_state; logic shutdown_now; // State machine (combinational) always_comb begin case (state) IDLE: next_state <= RUNNING; RUNNING: next_state <= shutdown ? SHUTDOWN : RUNNING; SHUTDOWN: next_state <= SHUTDOWN; default: next_state <= SHUTDOWN; endcase end // Sequential Behavior always_ff @ (posedge clk) begin // Some code here if (/*some condition) begin shutdown_now = 1'b0; end else begin shutdown_now = 1'b1; end state <= next_state; end

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  • SQL Concurrent test update question

    - by ptoinson
    Howdy Folks, I have a SQLServer 2008 database in which I have a table for Tags. A tag is just an id and a name. The definition of the tags table looks like: CREATE TABLE [dbo].[Tag]( [ID] [int] IDENTITY(1,1) NOT NULL, [Name] [varchar](255) NOT NULL CONSTRAINT [PK_Tag] PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ) Name is also a unique index. further I have several processes adding data to this table at a pretty rapid rate. These processes use a stored proc that looks like: ALTER PROC [dbo].[lg_Tag_Insert] @Name varchar(255) AS DECLARE @ID int SET @ID = (select ID from Tag where Name=@Name ) if @ID is null begin INSERT Tag(Name) VALUES (@Name) RETURN SCOPE_IDENTITY() end else begin return @ID end My issues is that, other than being a novice at concurrent database design, there seems to be a race condition that is causing me to occasionally get an error that I'm trying to enter duplicate keys (Name) into the DB. The error is: Cannot insert duplicate key row in object 'dbo.Tag' with unique index 'IX_Tag_Name'. This makes sense, I'm just not sure how to fix this. If it where code I would know how to lock the right areas. SQLServer is quite a different beast. First question is what is the proper way to code this 'check, then update pattern'? It seems I need to get an exclusive lock on the row during the check, rather than a shared lock, but it's not clear to me the best way to do that. Any help in the right direction will be greatly appreciated. Thanks in advance.

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  • How do I fetch a set of rows from data table

    - by cmrhema
    Hi, I have a dataset that has two datatables. In the first datatable I have EmpNo,EmpName and EmpAddress In the second datatable I have Empno,EmpJoindate, EmpSalary. I want a result where I should show EmpName as the label and his/her details in the gridview I populate a datalist with the first table, and have EmpNo as the datakeys. Then I populate the gridview inside the datatable which has EmpNo,EmpJoinDate and EmpAddress. My code is some what as below Datalist1.DataSource = dt; Datalist1.DataBind(); for (int i = 0; i < Datalist1.Items.Count; i++) { int EmpNo = Convert.ToInt32(Datalist1.DataKeys[i]); GridView gv = (GridView)Datalist1.FindControl("gv"); gv.DataSource = dt2; gv.DataBind(); } Now I have a problem, I have to bind the Details of the corresponding Employee to the gridview. Whereas the above code will display all the details of all employees in the gridview. If we use IEnumerable we give a condition where(a=a.eno=EmpNo), and bind that list to the gridview. How do I do this in datatable. kindly do not give me suggestions of altering the stored procedure which results the values in two tables, because that cannot be altered. I have to find a solution within the existing objects I have. Regards Hema

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  • How do I stop the m2eclipse plugin interfering with command line mvn builds?

    - by locka
    I use the m2eclipse plugin in Eclipse so that I can import a Maven project. The plugin reads the pom.xml and sorts out the dependencies in the projects in an Eclipse friendly way so I'm not looking at a sea of broken references and errors. I use Eclipse for code development however I usually build the projects from the command line, e.g. "mvn clean install". Unfortunately when I do this, m2eclipse detects disk activity and attempts to rebuild the workspace. This interferes with the command line build and sometimes results in a race condition. For example the command line might be in its clean phase but fails because it tries to delete a file or directory which is locked during the workspace rebuild. Aside from that workspace rebuilding is incredibly slow, and between failed builds and wasted CPU my build process is 2-3x longer than it should be. It isn't an option to not use Eclipse (e.g. to use Netbeans), or to disable m2eclipse. It is a useful plugin except for this behaviour. So my question is, how do I stop m2eclipse from rebuilding the workspace all the time? Can I invoke a manual refresh and otherwise disable this behaviour?

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  • Are dots legal in the name property of an HTML button

    - by justSteve
    a page with a bit of MVC code: <%=Html.SubmitButton("ChooseWebinar.Submit", "Continue to Registration Details")%><br/> that generates an input button where the '.' is embedded in the name: [rendered html] At page load this control (the submit button) is hidden - when one of two different dropdowns registers a value, the button is shown: function toggleChooseWebinarSubmit() { if ($("#ChooseWebinar_RecordedWebinarId").val() || $("#ChooseWebinar_UpcomingWebinarId").val()) { $("#ChooseWebinar_Submit").show(); } else { $("#ChooseWebinar_Submit").hide(); } I've just received a report from an IE8 user who says that after selecting a value in a dropdown, the button is _not displaying. I can't reproduce the condition (i've tried compatibility mode too). Obviously the show/hide is targeting the 'ID' selector but i can't help but wonder about that period in the control's name. Any known issues? - or perhaps the .change is problematic and the toggle's never getting called: $(window).load(function() { toggleChooseWebinarSubmit(); $("#ChooseWebinar_UpcomingWebinarId").change(function() { if ($(this).val()) { $("#ChooseWebinar_RecordedWebinarId").val(""); } toggleChooseWebinarSubmit(); }); $("#ChooseWebinar_RecordedWebinarId").change(function() { if ($(this).val()) { $("#ChooseWebinar_UpcomingWebinarId").val(""); } toggleChooseWebinarSubmit(); }); }); thx

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  • How to generate random numbers of lognormal distribution within specific range in Matlab

    - by Harpreet
    My grain sizes are defined as D=[1.19,1.00,0.84,0.71,0.59,0.50,0.42]. The problem is described below in steps. Grain sizes should follow lognormal distribution. The mean of the grain sizes is fixed as 0.84 and the standard deviation should be as low as possible but not zero. 90% of the grains (by weight %) fall in the size range of 1.19 to 0.59, and the rest 10% fall in size range of 0.50 to 0.42. Now I want to find the probabilities (weight percentage) of the grains falling in each grain size. It is allowable to split this grain size distribution into further small sizes but it must always be in the range of 1.19 and 0.42, i.e. 'D' can be continuous but 0.42 < D < 1.19. I need it fast. I tried on my own but I am not able to get the correct result. I am getting negative probabilities (weight percentages). Thanks to anyone who helps. I didn't incorporate the point 3 as I came to know about that condition later. Here are simple steps I tried: %% D=[1.19,1.00,0.84,0.71,0.59,0.50,0.42]; s=0.30; % std dev of the lognormal distribution m=0.84; % mean of the lognormal distribution mu=log(m^2/sqrt(s^2+m^2)); % mean of the associated normal dist. sigma=sqrt(log((s^2/m^2)+1)); % std dev of the associated normal dist. [r,c]=size(D); for i=1:c D(i)=mu+(sigma.*randn(1)); w(i)=(log(D(i))-mu)/sigma; % the probability or the wt. percentage of the grain sizes end grain_size=exp(D); %%

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