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  • Can anyone give me tips how to solve this using Graphs in C or Java?

    - by peiska
    Can anyone give me tips how to solve this using Graphs in C or Java? I have a rectangular sector, that I have to escape, and I have energy that goes disappear every step that i give in the area. I have to give the only one possible solution, the one that uses the least number of steps. If there are at least two sectors with the same number of steps (X1, Y1) and (X2, Y2) then choose the first if X1 < X2 or if X1 = X2 and Y1 < Y2. the position( 1,1) corresponds to the upper left corner. Examples: This is one sector,and i start with 40 of energy and in the position (3,3) 12 11 12 11 3 12 12 12 11 11 12 2 1 13 11 11 12 2 13 2 14 10 11 13 3 2 1 12 10 11 13 13 11 12 13 12 12 11 13 11 13 12 13 12 12 11 11 11 11 13 13 10 10 13 11 12 the best solution to exit the sector is the position (5, 1) the remain energy is 12 and i need 8 steeps to leave the area. for this sector i start with 8 of energy and in the position (3,4). 4 3 3 2 2 3 2 2 5 2 2 2 3 3 2 1 2 2 3 2 2 4 3 3 2 2 4 1 3 1 4 3 2 3 1 2 2 3 3 0 3 4 And for this one there is no way out, cause it looses all the energy.

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  • ExtJS 4 Chart Axis Display Issue in Chrome

    - by SerEnder
    I've run into an issue while using ExtJS 4.0.7. I'm trying to display a chart with two series on a Numeric/Category Chart. The chart displays correctly in Firefox, but while using Chrome (18.0.1025.142) the x axis labels are either all stacked upon each or else (when using rotate) rendered behind the chart in the specified angle. Any ideas would be appreciated. Screen shot in Firefox: Screen Shot in Chrome: And the code that's used to generate both: Ext.require(['Ext.chart.*']); Ext.onReady(function() { var iChartWidth = 800; // Defines chart width var iChartHeight = 550; // Defines chart height Ext.define('RulesCreatedModel',{ extend:'Ext.data.Model', fields:[ {name:'sHourName', type:'string'}, {name:'User_2', type:'number'}, {name:'User_1', type:'number'}, ] }); var RulesCreatedStore = Ext.create('Ext.data.Store',{ id:'RulesCreatedStore', model:'RulesCreateModel', fields: [ 'sHourName','dayNum','hour','User_2','User_1'], data:[{ 'sHourName':'3pm', 'User_1':82, 'User_2':56 },{ 'sHourName':'4pm', 'User_1':39, 'User_2':44 },{ 'sHourName':'5pm', 'User_1':80, 'User_2':14 },{ 'sHourName':'6pm', 'User_1':55, 'User_2':0, },{ 'sHourName':'7pm', 'User_1':36, 'User_2':0, },{ 'sHourName':'8pm', 'User_1':66, 'User_2':0 },{ 'sHourName':'9pm', 'User_1':39, 'User_2':0, },{ 'sHourName':'10pm', 'User_1':0, 'User_2':0 },{ 'sHourName':'11pm', 'User_1':0, 'User_2':0 },{ 'sHourName':'12am', 'User_1':0, 'User_2':0 },{ 'sHourName':'1am', 'User_1':0, 'User_2':0 },{ 'sHourName':'2am', 'User_1':0, 'User_2':0 },{ 'sHourName':'3am', 'User_1':0, 'User_2':0 },{ 'sHourName':'4am', 'User_1':0, 'User_2':0 },{ 'sHourName':'5am', 'User_1':0, 'User_2':0 },{ 'sHourName':'6am', 'User_1':0, 'User_2':0 },{ 'sHourName':'7am', 'User_1':0, 'User_2':1 },{ 'sHourName':'8am', 'User_1':0, 'User_2':99 },{ 'sHourName':'9am', 'User_1':0, 'User_2':28 },{ 'sHourName':'10am', 'User_1':0, 'User_2':28 },{ 'sHourName':'11am', 'User_1':0, 'User_2':153 },{ 'sHourName':'12pm', 'User_1':0, 'User_2':58 },{ 'sHourName':'1pm', 'User_1':0, 'User_2':42 },{ 'sHourName':'2pm', 'User_1':20, 'User_2':10 }] }); Ext.create('Ext.chart.Chart',{ id: 'RulesWrittenChart', renderTo: 'StatCharts_Display', width: iChartWidth, height: iChartHeight, animate: true, store: RulesCreatedStore, axes: [{ type: 'Numeric', position: 'left', fields: ['User_2','User_1'], title: 'Rules Written', grid: true },{ type: 'Category', position: 'bottom', fields: ['sHourName'], title: 'Hour', grid: false, label: { rotate: { degrees: 315 } } }], series: [{ type: 'line', axis: 'left', xField: 'sHourName', yField: 'User_2', highlight: { size: 3, radius: 3 } },{ type: 'line', axis: 'left', xField: 'sHourName', yField: 'User_1', highlight: { size: 3, radius: 3 } }] }); });

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  • What is the preferred way to update database schemas in multiple production environments

    - by rmarimon
    I am about to install some 20 servers with the same web application in multiple locations connected to their own local database. I will be updating the web applications remotely (perhaps using debian's package manager) and I'm sure will eventually need to update the database schemas. Since each server could be eventually be using a different release of the web application, I need a way to apply the incremental changes to the servers. I'm thinking something like this. Let's start with database.schema.1 as the original release of the database and assume this number increases with each new version of the schema. I eventually could end up with database.schema.17 as the current release. For a new installation this would be the schema to install. It seems to me that I would need consecutive translations like database.translation.1.2 which would convert database.schema.1 into database.schema.2, database.translation.2.3 to convert from 2 to 3 and so on until 17. It seems that whenever I change a schema I need to alter the database but perhaps I need to run some script to update the data which might be done with SQL but might require an external non sql script. What is the appropriate way to organize all these files? What is the automatic way to apply those upgrades to the schema? Where do I store the current version number of the schema?

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  • Ruby - calling constructor without arguments & removal of new line characters

    - by Raj
    I am a newbie at Ruby, I have written down a sample program. I dont understand the following: Why constructor without any arguments are not called in Ruby? How do we access the class variable outside the class' definition? Why does it always append newline characters at the end of the string? How do we strip it? Code: class Employee attr_reader :empid attr_writer :empid attr_writer :name def name return @name.upcase end attr_accessor :salary @@employeeCount = 0 def initiaze() @@employeeCount += 1 puts ("Initialize called!") end def getCount return @@employeeCount end end anEmp = Employee.new print ("Enter new employee name: ") anEmp.name = gets() print ("Enter #{anEmp.name}'s employee ID: ") anEmp.empid = gets() print ("Enter salary for #{anEmp.name}: ") anEmp.salary = gets() theEmpName = anEmp.name.split.join("\n") theEmpID = anEmp.empid.split.join("\n") theEmpSalary = anEmp.salary.split.join("\n") anEmp = Employee.new() anEmp = Employee.new() theCount = anEmp.getCount puts ("New employee #{theEmpName} with employee ID #{theEmpID} has been enrolled, welcome to hell! You have been paid as low as $ #{theEmpSalary}") puts ("Total number of employees created = #{theCount}") Output: Enter new employee name: Lionel Messi Enter LIONEL MESSI 's employee ID: 10 Enter salary for LIONEL MESSI : 10000000 New employee LIONEL MESSI with employee ID 10 has been enrolled, welcome to hell! You have been paid as low as $ 10000000 Total number of employees created = 0 Thanks

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  • Django aggregation on a date range

    - by klaut
    Hi all, I have been lurking and learning in here for a while. Now i have a problem that somehow i cannot see an easy solution. In order to learn django i am bulding an app that basically keeps track of booked items. What I would like to do is to show how many days per month for a selected year one item has been booked. i have the following models: Asset(Model) BookedAsset(Model): asset = models.ForeignKey(Asset) startdate = models.DateField() enddate = models.DateField() So having the following entries: asset 1, 2010-02-11, 2010-02-13 asset 2, 2010-03-12, 2010-03-14 asset 1, 2010-04-30, 2010-05-01 I would like to get returned the following: asset 1 asset 2 ------- ------- Jan = 0 Jan = 0 Feb = 2 Feb = 0 Mar = 0 Mar = 2 Apr = 1 Apr = 0 May = 1 May = 0 Jun = 0 Jun = 0 Jul = 0 Jul = 0 Aug = 0 Aug = 0 Sep = 0 Sep = 0 Oct = 0 Oct = 0 Nov = 0 Nov = 0 Dec = 0 Dec = 0 I know i need to first get the number of days in a date range (and keep track if they fall out of the current month and into the next month) and then do an agregate on the number of days. I am just stuck on how to do it elegantly in Django. Any help (or hint in the right direction) is greatly appreciated.

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  • How do I create efficient instance variable mutators in Matlab?

    - by Trent B
    Previously, I implemented mutators as follows, however it ran spectacularly slowly on a recursive OO algorithm I'm working on, and I suspected it may have been because I was duplicating objects on every function call... is this correct? %% Example Only obj2 = tripleAllPoints(obj1) obj.pts = obj.pts * 3; obj2 = obj1 end I then tried implementing mutators without using the output object... however, it appears that in MATLAB i can't do this - the changes won't "stick" because of a scope issue? %% Example Only tripleAllPoints(obj1) obj1.pts = obj1.pts * 3; end For application purposes, an extremely simplified version of my code (which uses OO and recursion) is below. classdef myslice properties pts % array of pts nROW % number of rows nDIM % number of dimensions subs % sub-slices end % end properties methods function calcSubs(obj) obj.subs = cell(1,obj.nROW); for i=1:obj.nROW obj.subs{i} = myslice; obj.subs{i}.pts = obj.pts(1:i,2:end); end end function vol = calcVol(obj) if obj.nROW == 1 obj.volume = prod(obj.pts); else obj.volume = 0; calcSubs(obj); for i=1:obj.nROW obj.volume = obj.volume + calcVol(obj.subs{i}); end end end end % end methods end % end classdef

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  • Prototypal inheritance should save memory, right?

    - by Techpriester
    Hi Folks, I've been wondering: Using prototypes in JavaScript should be more memory efficient than attaching every member of an object directly to it for the following reasons: The prototype is just one single object. The instances hold only references to their prototype. Versus: Every instance holds a copy of all the members and methods that are defined by the constructor. I started a little experiment with this: var TestObjectFat = function() { this.number = 42; this.text = randomString(1000); } var TestObjectThin = function() { this.number = 42; } TestObjectThin.prototype.text = randomString(1000); randomString(x) just produces a, well, random String of length x. I then instantiated the objects in large quantities like this: var arr = new Array(); for (var i = 0; i < 1000; i++) { arr.push(new TestObjectFat()); // or new TestObjectThin() } ... and checked the memory usage of the browser process (Google Chrome). I know, that's not very exact... However, in both cases the memory usage went up significantly as expected (about 30MB for TestObjectFat), but the prototype variant used not much less memory (about 26MB for TestObjectThin). I also checked: The TestObjectThin instances contain the same string in their "text" property, so they are really using the property of the prototype. Now, I'm not so sure what to think about this. The prototyping doesn't seem to be the big memory saver at all. I know that prototyping is a great idea for many other reasons, but I'm specifically concerned with memory usage here. Any explanations why the prototype variant uses almost the same amount of memory? Am I missing something?

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  • lots of backbone views - performance issues?

    - by ksol
    tl;dr: I wonder if having lots (100+ for the moment, potentially up to 1000/2000 or more) of backbone views (as a cell of a table) is too heavy or not The project I'm working on revolves around a planning view. There one row per user that covers 6 hours of a day, each hour splitted in 4 slots of 15mn. This planning is used to add "reservations" when clicking on a slot, and should handle hovering of the correct slots, and also handle when it is NOT possible to make a reservation - ie. prevent user click on an "unavailable" slot. There is many reasons why a slot can't be clicked on: the user is not available at this time, or the user is in a reservation; or the app needs to "force" a delay slot between two reservations. Reservations (a div) are rendered in a slot (a cell of a table), and by toying with dimensions, hovers the right number of slots. All this screen is handled with backbone. So For each slot I'm hovering on, I need to check wether I can do a reservation here or not. As of this moment, I use this by toying with the data attributes on the slots : when a reservation object is added, the slots covered are "enhanced with (among others) the reservation object (the backbone view object). But in some cases I don't quite have a grasp on now, it mixes up, and when the reservation view is removed, the slots are not "cleaned up" : the previous class is not reset correctly. It is probably something I've done wrong or badly, but this is only going to get heavier; I think I should use another class of Backbone views here, but I'm afraid the number of slots and thereof of views objects will be high and cause performance issue. I don't know mush about js perf so I'd like to have some feedback before jumping on that train. Any other advice on how to do this would be quite welcomed too. Thanks for your time. If this is not clear enough, tell me, I'll try and rephrase it.

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  • How to retrieve a numbered sequence range from a List of filenames?

    - by glenneroo
    I would like to automatically parse the entire numbered sequence range of a List<FileData> of filenames (sans extensions) by checking which part of the filename changes. Here is an example (file extension already removed): First filename: IMG_0000 Last filename: IMG_1000 Numbered Range I need: 0000 to 1000 Except I need to deal with every possible type of file naming convention such as: 0000 ... 9999 20080312_0000 ... 20080312_9999 IMG_0000 - Copy ... IMG_9999 - Copy 8er_green3_00001 .. 8er_green3_09999 etc. I need the entire 0-padded range e.g. 0001 not just 1 The sequence number is 0-padded e.g. 0001 The sequence number can be located anywhere e.g. IMG_0000 - Copy The range can start and end with anything i.e. doesn't have to start with 1 and end with 9999 Whenever I get something working for 8 random test cases, the 9th test breaks everything and I end up re-starting from scratch. I've currently been comparing only the first and last filenames (as opposed to iterating through all filenames): void FindRange(List<FileData> files, out string startRange, out string endRange) { string firstFile = files.First().ShortName; string lastFile = files.Last().ShortName; ... } Does anyone have any clever ideas?

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  • curl not returning content length header

    - by Michael P. Shipley
    Trying to get image file size using curl but content length header is not returned: $url ="http://www.collegefashion.net/wp-content/plugins/feed-comments-number/image.php?1263"; $fp = curl_init(); curl_setopt($fp, CURLOPT_NOBODY, true); curl_setopt($fp, CURLOPT_RETURNTRANSFER, 1); curl_setopt($fp, CURLOPT_FAILONERROR,1); curl_setopt($fp, CURLOPT_REFERER,''); curl_setopt($fp, CURLOPT_URL, $url); curl_setopt($fp, CURLOPT_HEADER,1); curl_setopt($fp, CURLOPT_USERAGENT,'Mozilla/5.0'); $body = curl_exec($fp); var_dump($body): HTTP/1.1 200 OK Date: Sun, 02 May 2010 02:50:20 GMT Server: Apache/2.0.63 (CentOS) X-Powered-By: W3 Total Cache/0.8.5.2 X-Pingback: http://www.collegefashion.net/xmlrpc.php Cache-Control: no-cache, must-revalidate Expires: Sat, 26 Jul 1997 05:00:00 GMT Content-Type: image/png It works via ssh though: curl -i http://www.collegefashion.net/wp-content/plugins/feed-comments-number/image.php?1263 HTTP/1.1 200 OK Date: Sun, 02 May 2010 03:38:43 GMT Server: Apache/2.0.63 (CentOS) X-Powered-By: W3 Total Cache/0.8.5.2 X-Pingback: http://www.collegefashion.net/xmlrpc.php Cache-Control: no-cache, must-revalidate Expires: Sat, 26 Jul 1997 05:00:00 GMT Content-Length: 347 Content-Type: image/png

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  • How to hide labels in html

    - by user225269
    I have this code which depends on this javascript from dynamic drive: http://dynamicdrive.com/dynamicindex16/formdependency.htm Its a form dependency manager. Which will show or hide elements depending on what you choose from the forms that are revealed: I don't know why but If I alter the code from this: <td> <label>ID Number<input type="checkbox" name="id" class="DEPENDS ON info BEING student"></label> </td> </tr> To this: <td> <input type="hidden" class="DEPENDS ON info BEING student"> <label style="margin-bottom: 1em; padding-bottom: 1em; border-bottom: 3px silver groove;"></label> <tr> <td> <input type="checkbox" name="id" class="DEPENDS ON info BEING student"><label>ID Number</label> </td> </tr> Note: The only change that I did here is to transfer the label from the left side of the checkbox to the right side so that they will look better. But when I do this. The labels will be visible even if I did not yet click on the button that will make it visible(but without the checkboxes). And when I click on that button, that's the only time when the checkbox will appear on the left side of the labels. The checkbox is ok, but the label is not. And the javascript is working properly. What do I do so that the checkbox and label will go together?

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  • ASP.Net Gridview paging, pageindex always == 0.

    - by David Archer
    Hi all, Having a slight problem with my ASP.Net 3.5 app. I'm trying to get the program to pick up what page number has been clicked. I'm using ASP.Net's built in AllowPaging="True" function. It's never the same without code, so here it is: ASP.Net: <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="Vertical" Width="960px" AllowSorting="True" EnableSortingAndPagingCallbacks="True" AllowPaging="True" PageSize="25" > <RowStyle BackColor="#F7F6F3" ForeColor="#333333" /> <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" /> <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#999999" /> <AlternatingRowStyle BackColor="White" ForeColor="#284775" /> </asp:GridView> C#: var fillTable = from ft in db.IncidentDatas where ft.pUserID == Convert.ToInt32(ClientList.SelectedValue.ToString()) select new { Reference = ft.pRef.ToString(), Date = ft.pIncidentDateTime.Value.Date.ToShortDateString(), Time = ft.pIncidentDateTime.Value.TimeOfDay, Premesis = ft.pPremises.ToString(), Latitude = ft.pLat.ToString(), Longitude = ft.pLong.ToString() }; if (fillTable.Count() > 0) { GridView1.DataSource = fillTable; GridView1.DataBind(); var IncidentDetails = fillTable.ToList(); for (int i = 0; i < IncidentDetails.Count(); i++) { int pageno = GridView1.PageIndex; int pagenostart = pageno * 25; if (i >= pagenostart && i < (pagenostart + 25)) { //Processing } } } Any idea why GridView1.PageIndex is always = 0? The thing is, the processing works correctly for the grid view.... it will always go to the correct paging page, but it's always 0 when I try to get the number. Help!

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  • Flag bit computation and detection

    - by Majid
    Hi all, In some code I'm working on I should take care of ten independent parameters which can take one of two values (0 or 1). This creates 2^10 distinct conditions. Some of the conditions never occur and can be left out, but those which do occur are still A LOT and making a switch to handle all cases is insane. I want to use 10 if statements instead of a huge switch. For this I know I should use flag bits, or rather flag bytes as the language is javascript and its easier to work with a 10 byte string with to represent a 10-bit binary. Now, my problem is, I don't know how to implement this. I have seen this used in APIs where multiple-selectable options are exposed with numbers 1, 2, 4, 8, ... , n^(n-1) which are decimal equivalents of 1, 10, 100, 1000, etc. in binary. So if we make call like bar = foo(7), bar will be an object with whatever options the three rightmost flags enable. I can convert the decimal number into binary and in each if statement check to see if the corresponding digit is set or not. But I wonder, is there a way to determine the n-th digit of a decimal number is zero or one in binary form, without actually doing the conversion?

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  • Getting unpredictable data into a tabular format

    - by Acorn
    The situation: Each page I scrape has <input> elements with a title= and a value= I don't know what is going to be on the page. I want to have all my collected data in a single table at the end, with a column for each title. So basically, I need each row of data to line up with all the others, and if a row doesn't have a certain element, then it should be blank (but there must be something there to keep the alignment). eg. First page has: {animal: cat, colour: blue, fruit: lemon, day: monday} Second page has: {animal: fish, colour: green, day: saturday} Third page has: {animal: dog, number: 10, colour: yellow, fruit: mango, day: tuesday} Then my resulting table should be: animal | number | colour | fruit | day cat | none | blue | lemon | monday fish | none | green | none | saturday dog | 10 | yellow | mango | tuesday Although it would be good to keep the order of the title value pairs, which I know dictionaries wont do. So basically, I need to generate columns from all the titles (kept in order but somehow merged together) What would be the best way of going about this without knowing all the possible titles and explicitly specifying an order for the values to be put in?

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  • PHP + MYSQLI: Variable parameter/result binding with prepared statements.

    - by Brian Warshaw
    In a project that I'm about to wrap up, I've written and implemented an object-relational mapping solution for PHP. Before the doubters and dreamers cry out "how on earth?", relax -- I haven't found a way to make late static binding work -- I'm just working around it in the best way that I possibly can. Anyway, I'm not currently using prepared statements for querying, because I couldn't come up with a way to pass a variable number of arguments to the bind_params() or bind_result() methods. Why do I need to support a variable number of arguments, you ask? Because the superclass of my models (think of my solution as a hacked-up PHP ActiveRecord wannabe) is where the querying is defined, and so the find() method, for example, doesn't know how many parameters it would need to bind. Now, I've already thought of building an argument list and passing a string to eval(), but I don't like that solution very much -- I'd rather just implement my own security checks and pass on statements. Does anyone have any suggestions (or success stories) about how to get this done? If you can help me solve this first problem, perhaps we can tackle binding the result set (something I suspect will be more difficult, or at least more resource-intensive if it involves an initial query to determine table structure).

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  • Newsletter send using AJAX to avoid PHP timeout

    - by simPod
    I need to send newsletters. I have already a PHP script that sends mass emails but it won't work for long as email database is growing because of PHP max script run time. So, to avoid it I came up with a solution: I would call my PHP script using AJAX in javascript and I will give it $_GET parameter with a count 20 so the script would sent only 20 emails. Than AJAX would receive success response, and call my script again and again till all emails are send. Is it possible? I'm asking because I have never seen such a solution so I'm wondering if it is real (It's kinda hard to implement this into my PHP framework so I'm asking experts here first) To sum it up here's a code skeleton: <script> var emailCount = 1000; //would get this from DB var runCount = 20; //number of emails sent in one cycle var from = 0; //start number function sendMail(){ if(from<emailCount){ jQuery.ajaxfunction({ path: 'script.php?from='+from+'&count='+runCount successFc: function(){ from+=runCount; sendMail(); } }) } } sendMail(); </script> So, are there any obstacles? Thanks a lot.

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  • Very slow guards in my monadic random implementation (haskell)

    - by danpriduha
    Hi! I was tried to write one random number generator implementation, based on number class. I also add there Monad and MonadPlus instance. What mean "MonadPlus" and why I add this instance? Because of I want to use guards like here: -- test.hs -- import RandomMonad import Control.Monad import System.Random x = Rand (randomR (1 ::Integer, 3)) ::Rand StdGen Integer y = do a <-x guard (a /=2) guard (a /=1) return a here comes RandomMonad.hs file contents: -- RandomMonad.hs -- module RandomMonad where import Control.Monad import System.Random import Data.List data RandomGen g => Rand g a = Rand (g ->(a,g)) | RandZero instance (Show g, RandomGen g) => Monad (Rand g) where return x = Rand (\g ->(x,g)) (RandZero)>>= _ = RandZero (Rand argTransformer)>>=(parametricRandom) = Rand funTransformer where funTransformer g | isZero x = funTransformer g1 | otherwise = (getRandom x g1,getGen x g1) where x = parametricRandom val (val,g1) = argTransformer g isZero RandZero = True isZero _ = False instance (Show g, RandomGen g) => MonadPlus (Rand g) where mzero = RandZero RandZero `mplus` x = x x `mplus` RandZero = x x `mplus` y = x getRandom :: RandomGen g => Rand g a ->g ->a getRandom (Rand f) g = (fst (f g)) getGen :: RandomGen g => Rand g a ->g -> g getGen (Rand f) g = snd (f g) when I run ghci interpreter, and give following command getRandom y (mkStdGen 2000000000) I can see memory overflow on my computer (1G). It's not expected, and if I delete one guard, it works very fast. Why in this case it works too slow? What I do wrong?

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  • Generic callbacks

    - by bobobobo
    Extends So, I'm trying to learn template metaprogramming better and I figure this is a good exercise for it. I'm trying to write code that can callback a function with any number of arguments I like passed to it. // First function to call int add( int x, int y ) ; // Second function to call double square( double x ) ; // Third func to call void go() ; The callback creation code should look like: // Write a callback object that // will be executed after 42ms for "add" Callback<int, int, int> c1 ; c1.func = add ; c1.args.push_back( 2 ); // these are the 2 args c1.args.push_back( 5 ); // to pass to the "add" function // when it is called Callback<double, double> c2 ; c2.func = square ; c2.args.push_back( 52.2 ) ; What I'm thinking is, using template metaprogramming I want to be able to declare callbacks like, write a struct like this (please keep in mind this is VERY PSEUDOcode) <TEMPLATING ACTION <<ANY NUMBER OF TYPES GO HERE>> > struct Callback { double execTime ; // when to execute TYPE1 (*func)( TYPE2 a, TYPE3 b ) ; void* argList ; // a stored list of arguments // to plug in when it is time to call __func__ } ; So for when called with Callback<int, int, int> c1 ; You would automatically get constructed for you by < HARDCORE TEMPLATING ACTION > a struct like struct Callback { double execTime ; // when to execute int (*func)( int a, int b ) ; void* argList ; // this would still be void*, // but I somehow need to remember // the types of the args.. } ; Any pointers in the right direction to get started on writing this?

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  • need help fixing unique key in rails. rails is adding id causing duplicate key

    - by railsnew
    I need some help in fixing the below issue. I had transaction blocks in my rails code like below: @sqlcontact = "INSERT INTO contacts (id,\"cid\", \"hphone\", mphone, provider, cemail, email, sms , mail, phone) VALUES ('"+@id1+"','" + @id1 + "', '"+ params[:hphone] + "', '"+params[:mphone]+ "', '" + params[:provider] + "', '" + params[:cemail]+ "', '" + @varemail+ "', '"+@varsms+ "', '"+ @varmail+"', '"+@varphone+"')" my app was deployed to heroku so I was advised by them to remove transaction blocks. So I changed the above to: @cont = Contact.new(:id => @id1, :cid => @id1, :hphone => params[:hphone], :mphone => params[:mphone], :provider => params[:provider], :cemail => params[:cemail], :email => @varemail, :sms => @varsms, :mail => @varmail, :phone => @varphone) @cont.save My app also already had data stored. Now the problem is that when I try to save a record ...I keep getting the error: duplicate key value violates unique constraint "contacts_pkey" The error also shows the sql query trying to insert data ...however, in that sql query i Do not see id value. As you can see from my code that I am passing the id. then why is rails not accepting it? does it always include its own sequential id? can I not overwrite the default rails magic? and if it does that...does it not look at data that is already in the DB?? I am really stuck here. What should I do? should I just go back to my transaction block

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  • Problem with Active Record

    - by kshchepelin
    Hello everyone. Lets assume we have a User model. And user can plan some activities. The number of types of activities is about 50. All activities have common properties, such as start_time, end_time, user_id, etc. But each of them has some unique properties. Now we have each activity living in its own table in DB. And thats why we have such terrible sql queries like SELECT * FROM `first_activities_table` WHERE (`first_activity`.`id` IN (17,18)) SELECT * FROM `second_activities_table` WHERE (`second_activity`.`id` = 17) ..... SELECT * FROM `n_activities_table` WHERE (`n_activity`.`id` = 44) About 50 queries. That's terrible. There are different ways to solve this. Choose the activity type with the biggest number of properties, create the table 'Activities' and have STI model. But this way we must name our columns in uncomfortable way and often the record in that table would have some NULL fields. Also STI model, but having columns, common for all of activity types and some blob column with serialized properties. But we have to do some search on activities - there can be a problem. And serialization is quite slow. Please help me dealing with this. Maybe my problem has quite different solution that will fit my needs. Thanks for help.

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  • Precision of Interval for PL/SQL Function value

    - by Gary
    Generally, when you specify a function the scale/precision/size of the return datatype is undefined. For example, you say FUNCTION show_price RETURN NUMBER or FUNCTION show_name RETURN VARCHAR2. You are not allowed to have FUNCTION show_price RETURN NUMBER(10,2) or FUNCTION show_name RETURN VARCHAR2(20), and the function return value is unrestricted. This is documented functionality. Now, I get an precision error (ORA-01873) if I push 9999 hours (about 400 days) into the following. The limit is because the default days precision is 2 DECLARE v_int INTERVAL DAY (4) TO SECOND(0); FUNCTION hhmm_to_interval return INTERVAL DAY TO SECOND IS v_hhmm INTERVAL DAY (4) TO SECOND(0); BEGIN v_hhmm := to_dsinterval('PT9999H'); RETURN v_hhmm; -- END hhmm_to_interval; BEGIN v_int := hhmm_to_interval; end; / and it won't allow the precision to be specified directly as part of the datatype returned by the function. DECLARE v_int INTERVAL DAY (4) TO SECOND(0); FUNCTION hhmm_to_interval return INTERVAL DAY (4) TO SECOND IS v_hhmm INTERVAL DAY (4) TO SECOND(0); BEGIN v_hhmm := to_dsinterval('PT9999H'); RETURN v_hhmm; -- END hhmm_to_interval; BEGIN v_int := hhmm_to_interval; end; / I can use a SUBTYPE DECLARE subtype t_int is INTERVAL DAY (4) TO SECOND(0); v_int INTERVAL DAY (4) TO SECOND(0); FUNCTION hhmm_to_interval return t_int IS v_hhmm INTERVAL DAY (4) TO SECOND(0); BEGIN v_hhmm := to_dsinterval('PT9999H'); RETURN v_hhmm; -- END hhmm_to_interval; BEGIN v_int := hhmm_to_interval; end; / Any drawbacks to the subtype approach ? Any alternatives (eg some place to change a default precision) ? Working with 10gR2.

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  • How to calculate this string-dissimilarity function efficiently?

    - by ybungalobill
    Hello, I was looking for a string metric that have the property that moving around large blocks in a string won't affect the distance so much. So "helloworld" is close to "worldhello". Obviously Levenshtein distance and Longest common subsequence don't fulfill this requirement. Using Jaccard distance on the set of n-grams gives good results but has other drawbacks (it's a pseudometric and higher n results in higher penalty for changing single character). [original research] As I thought about it, what I'm looking for is a function f(A,B) such that f(A,B)+1 equals the minimum number of blocks that one have to divide A into (A1 ... An), apply a permutation on the blocks and get B: f("hello", "hello") = 0 f("helloworld", "worldhello") = 1 // hello world -> world hello f("abba", "baba") = 2 // ab b a -> b ab a f("computer", "copmuter") = 3 // co m p uter -> co p m uter This can be extended for A and B that aren't necessarily permutations of each other: any additional character that can't be matched is considered as one additional block. f("computer", "combuter") = 3 // com uter -> com uter, unmatched: p and b. Observing that instead of counting blocks we can count the number of pairs of indices that are taken apart by a permutation, we can write f(A,B) formally as: f(A,B) = min { C(P) | P:|A|?|B|, P is bijective, ?i?dom(P) A[P(i)]=B[P(i)] } C(P) = |A| + |B| - |dom(P)| - |{ i | i,i+1?dom(P) and P(i)+1=P(i+1) }| - 1 The problem is... guess what... ... that I'm not able to calculate this in polynomial time. Can someone suggest a way to do this efficiently? Or perhaps point me to already known metric that exhibits similar properties?

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  • UITableView only pushes to one controller

    - by Mitochondria
    So I have my UITableView, with 2 sections and 1 cell in each, and if I click the first one, it works, then the second one, it goes to the first controller. RootViewController is a navigationController, trying to push to ViewControllers. Here's the code for the tableView: // Customize the number of sections in the table view. - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 2; } // Customize the number of rows in the table view. - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { if(section == 0) return 1; else return 1; } - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{ if(section == 0){ return @"Terminal/SSH Guides"; }else{ return @"Cydia Tutorials"; } } // Customize the appearance of table view cells. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease]; } // Set up the cell... if(indexPath.section == 0){ cell.text = @"Changing Password for root"; } else { cell.text = @"Hiding Sections"; } return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { id newController; switch (indexPath.row) { case 0: newController = [[rootpassword alloc] initWithNibName:@"rootpassword" bundle:nil]; break; case 1: newController = [[hidingsections alloc] initWithNibName:@"hidingsections" bundle:nil]; break; default: break; } [self.navigationController pushViewController:newController animated:TRUE]; [tableView deselectRowAtIndexPath:indexPath animated:TRUE]; } I'm also having trouble adding more sections and rows/cells to sections. Thanks.

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  • Is it possible to order by a composite key with JPA and CriteriaBuilder

    - by Kjir
    I would like to create a query using the JPA CriteriaBuilder and I would like to add an ORDER BY clause. This is my entity: @Entity @Table(name = "brands") public class Brand implements Serializable { public enum OwnModeType { OWNER, LICENCED } @EmbeddedId private IdBrand id; private String code; //bunch of other properties } Embedded class is: @Embeddable public class IdBrand implements Serializable { @ManyToOne private Edition edition; private String name; } And the way I am building my query is like this: CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Brand> q = cb.createQuery(Brand.class).distinct(true); Root<Brand> root = q.from(Brand.class); if (f != null) { f.addCriteria(cb, q, root); f.addOrder(cb, q, root, sortCol, ascending); } return em.createQuery(q).getResultList(); And here are the functions called: public void addCriteria(CriteriaBuilder cb, CriteriaQuery<?> q, Root<Brand> r) { } public void addOrder(CriteriaBuilder cb, CriteriaQuery<?> q, Root<Brand> r, String sortCol, boolean ascending) { if (ascending) { q.orderBy(cb.asc(r.get(sortCol))); } else { q.orderBy(cb.desc(r.get(sortCol))); } } If I try to set sortCol to something like "id.edition.number" I get the following error: javax.ejb.EJBException: java.lang.IllegalArgumentException: Unable to resolve attribute [id.name] against path Any idea how I could accomplish that? I tried searching online, but I couldn't find a hint about this... Also would be great if I could do a similar ORDER BY when I have a @ManyToOne relationship (for instance, "id.edition.number")

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  • forward invocation, by hand vs magically?

    - by John Smith
    I have the following two class: //file FruitTree.h @interface FruitTree : NSObject { Fruit * f; Leaf * l; } @end //file FruitTree.m @implementation FruitTree //here I get the number of seeds from the object f @end //file Fruit @interface Fruit : NSObject { int seeds; } -(int) countfruitseeds; @end My question is at the point of how I request the number of seeds from f. I have two choices. Either: Since I know f I can explicitly call it, i.e. I implement the method -(int) countfruitseeds { return [f countfruitseeds]; } Or: I can just use forwardInvocation: - (NSMethodSignature *)methodSignatureForSelector:(SEL)selector { // does the delegate respond to this selector? if ([f respondsToSelector:selector]) return [f methodSignatureForSelector:selector]; else if ([l respondsToSelector:selector]) return [l methodSignatureForSelector:selector]; else return [super methodSignatureForSelector: selector]; } - (void)forwardInvocation:(NSInvocation *)invocation { [invocation invokeWithTarget:f]; } (Note this is only a toy example to ask my question. My real classes have lots of methods, which is why I am asking.) Which is the better/faster method?

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