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• Please help, now I have a matrix, I want use Combination algorithm to generate a array for length 6

  - by user313429

  The first thanks a lot for your help , the following is my matrix, I want to implement combination algorithm between multiple arrays in LINQ for this matrix. int[,] cj = { { 10, 23, 16, 20 }, { 22, 13, 1, 33 }, { 7, 19, 31, 12 }, { 30, 14, 21, 4 }, { 2, 29, 32, 6 }, { 18, 26, 17, 8 }, { 25, 11, 5, 28 }, { 24, 3, 15, 27 } }; other: public static IEnumerable<IEnumerable<T>> Combinations<T>(this IEnumerable<T> elements, int k) { return k == 0 ? new[] { new T[0] } : elements.SelectMany((e, i) => elements.Skip(i + 1).**Combinations**(k - 1).Select(c => (new[] { e }).Concat(c))); } The above method has a error in my project, System.Collections.Generic.IEnumerable' does not contain a definition for 'Combinations' and no extension method 'Combinations' accepting a first argument of type 'System.Collections.Generic.IEnumerable' could be found (are you missing a using directive or an assembly reference? I use .Net Framework3.5, what is the reason it?

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• Is there any way to load all UI controls before displaying? C# winform

  - by Nabil

  I have a complicate win form with lots of controls and bulky repaints, controls resizeing and positioning according to user screen, this causes the form to be shown while doing some rendering and repainting. Is there any way to load UI and prepare it before displaying??I mean showing final UI after the whole repainting events done. If using splash screen, before loading the main form, how should I do that?? Thanks

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• approximating log10[x^k0 + k1]

  - by Yale Zhang

  Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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• vba: funny notation with #??

  - by every_answer_gets_a_point

  what does this mean? if CDbl(Trim(Range("M" & r).Text)) > 0# then... what does the # do?? and what does cdbl do?

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• Stateful Iterators Java

  - by Gitmo

  What is a Stateful Iterator? This question relates to an Iterator defined in Hadoop for performing Joins. As the reference documentation states: This defines an interface to a stateful Iterator that can replay elements added to it directly. Note that this does not extend Iterator. What does 'replay elements added to it directly' mean? How is this iterator different from a usual iterator?

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• about null values!

  - by user329820

  Hi I have a question that if we declare a variable and then do not set it explicitly to null value then it would be null outomatically ,i mean that the below code will return true or false ? thanks DECLARE @val CHAR(4) If @val = NULL

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• j2ME setLocationListener()

  - by Jeff Catania

  I'm programming a GPS tracking system using the Motorola i335 running on Sprint's IDEN network. I'm using the javax.microedition.location api to find the GPS coordinates. To set up the updating, you use the [setLocationListener][1] method. I originally tried passing (listener,2,1,1). However there was too many invalid locations being received (where the GPS could not get the fix in the specified time), so I changed the parameters to (listener, 20, 20, 1). Now the system barely throws any invalid locations. My goal is to get the fastest number of updates that are realistic. Have any of you found a happy medium for parameters of this method? [1]: http://www-users.cs.umn.edu/~czhou/docs/jsr179/lapi/javax/microedition/location/LocationProvider.html#setLocationListener(javax.microedition.location.LocationListener, int, int, int)

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• What reasons for software developers to write open source projects?

  - by sashaeve

  What key reasons for software developers can you list so they will decide to make their products as open source (I don't mean products just for fun but real products)?

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• AHCI, Windows 7 and can only boot with Windows DVD present

  - by Rob Pridham

  Foolishly, I installed Windows 7 with my new SSD set to IDE. I would like to change it to AHCI. I have done this before, with a different motherboard. What happens: I set the controller to AHCI in the BIOS; I also check correct boot order On boot, I get the 'BOOTMGR not found' error I use the Windows Recovery Console on the DVD Diskpart etc can see the disks, and bootrec claims to have rewritten the MBR/bootloader I reboot, same problem Recovery Console again and it detects a problem, fixes, reboots Recovery Console again and it detects the OS, and a problem - fixes, reboots I ignore the 'press any key to boot from DVD' prompt Windows boots fine I restart without the DVD and I'm back to square one That optional 'press a key to boot from DVD' stage is something that the recovery process introduces - normally you have to choose to boot to the DVD at the BIOS stage. You also see this when installing Windows. I suspect that whatever temporary state that is is compatible with AHCI - but not the standard it returns to. I have done the msahci/iaStorV registry hacks to no avail (this worked with the previous board). I can put it back to IDE where normal service is resumed. The board is an Asus M5A99X, the southbridge is AMD SB950, and this is Windows 7 x64. I would quite like not to have to reinstall it again. Any ideas as to what I can do as a permanent fix?

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• Redirecting exec output to a buffer or file

  - by devin

  I'm writing a C program where I fork(), exec(), and wait(). I'd like to take the output of the program I exec'ed to write it to file or buffer. For example, if I exec ls I want to write file1 file2 etc to buffer/file. I don't think there is a way to read stdout, so does that mean I have to use a pipe? Is there a general procedure here that I haven't been able to find?

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• Splitting of string in python .

  - by mekasperasky

  A<<B would mean circling the characters of A towards left by the length of the data in B . So I am using split not the loop . But I am not able to figure out how to split a string according to the length of B.

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• Error using MVCContrib TestHelper

  - by Brian McCord

  While trying to implement the second answer to a previous question, I am receiving an error. I have implemented the methods just as the post shows, and the first three work properly. The fourth one (HomeController_Delete_Action_Handler_Should_Redirect_If_Model_Successfully_Delete) gives this error: Could not find a parameter named 'controller' in the result's Values collection. If I change the code to: actual .AssertActionRedirect() .ToAction("Index"); it works properly, but I don't like the "magic string" in there and prefer to use the lambda method that the other poster used. My controller method looks like this: [HttpPost] public ActionResult Delete(State model) { try { if( model == null ) { return View( model ); } _stateService.Delete( model ); return RedirectToAction("Index"); } catch { return View( model ); } } What am I doing wrong?

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• How do I format a String in an email so Outlook will print the line breaks?

  - by MattGrommes

  I'm trying to send an email in Java but when I read the body of the email in Outlook, it's gotten rid of all my linebreaks. I'm putting \n at the ends of the lines but is there something special I need to do other than that? The receivers are always going to be using Outlook. I found a page on microsoft.com that says there's a 'Remove line breaks' "feature" in Outlook so does this mean there's no solution to get around that other than un-checking that setting? Thanks

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• Merging code with dependencies? - Javascript

  - by RadiantHex

  Hi folks, this might be quite simple, but I must say I'm a bit confused on this topic. I'm writing code based on two popular libraries: jQuery underscore.js I am just wondering what would be the best way to isolate the code and prevent conflicts and how to merge it with its dependencies. By merging I mean putting them within the same file. :) I hope I'm not asking something which is too basic. ...and a last thing MERRY CHRISTMAS EVERYONE! =D

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• Code optimization - Unused methods

  - by Yochai Timmer

  How can I tell if a method will never be used ? I know that for dll files and libraries you can't really know if someone else (another project) will ever use the code. In general I assume that anything public might be used somewhere else. But what about private methods ? Is it safe to assume that if I don't see an explicit call to that method, it won't be used ? I assume that for private methods it's easier to decide. But is it safe to decide it ONLY for private methods ?

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• How can I debug or set a break statement inside an expression tree?

  - by Abel

  When an external library contains a LINQ provider, and it throws an exception when executing a dynamic expression tree, how can I break when that expression is thrown? For example, I use a third party LINQ2CRM provider, which allows me to call the Max<TSource, TResult>() method of IQueryable, but when it throws an InvalidCastException, I fail to break on the spot when the exception is thrown, making it hard to review the stack-trace because it's already unwinded when the debugger breaks it in my code. I've set "break on throw" for the mentioned exception. My debug settings are: Clarification on where exactly I'd want to break. I do not want to break in side the LINQ Expression, but instead, I want to break when the expression tree is executed, or, put in other words, when the IQueryable extension method Max() calls the override provided by the LINQ provider. The top of the stacktrace looks like this, which is where I would like to break inside (or step through, or whatever): at XrmLinq.QueryProviderBase.Execute[T](Expression expression) at System.Linq.Queryable.Max[TSource,TResult](IQueryable`1 source, Expression`1 selector)

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• The best way to use dictionary items as we use the advantages of List

  - by blgnklc

  I want to get use of dictionary items like I do in List generic class, e.g; foreach(item in ItemList) { item.BlaBla; } but in dictionary there s no chance, like e method above... Dictionary<string, HtmlInputImage> smartPenImageDictionary; I mean I got to know the key item for the dictionary item.. but what I want, I want to travel from beginning of the list till the end..

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• Saving auto increment in MySQL

  - by oshafran

  Hello, I am trying to sync between 2 tables: I have active table where has auto_increment, and I have archive table with the same values. I would like both ID's to be unique (between the tables as well) - I mean, I would like to save auto incremenet, and if I UNION both table I still have uniqness. How can I do that? Is there a possibility to save auto increment when mysql is off?

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• what is the Flash event listener when flash is exiting?

  - by envato

  Hi Guys, anybody knows how to make event listener for flash exiting? By mean exiting is when a tag that hold the flash object is removed so that you cant see the flash anymore... Thanks

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• SQL Server Merge statement issue

  - by George2

  Hello everyone, I am learning and using SQL Server 2008 new Merge statement, merge statement will compare/operate source table and destination table row by row ("operate" I mean operations performed for when matched or not-matched conditions). My question is whether the whole merge process will be one transaction or each row comparison/operation will be one transaction? Appreciate if any document to prove it. thanks in advance, George

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• Custom DataGridView column sort based on Value not Formatted value

  - by Dan Neely

  I have a custom DGV cell I'm using to display the contents of MyType objects. To control how they're being formatted I'm overriding the GetFormattedValue() and FormattedvalueType methods of DataGridViewTextBoxCell because in this case I don't want to use the default ToString() method. The problem is that when I do this the DGV is sorting the column by the string in FormattedValue instead of by Value. I'm not seeing a method I can override to change the sort behavior of the column. While I know I can, I don't want to have to write custom Sort mthods for the DGVs themselves because I'm using this in multiple DGV's.

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• How do you create a transaction that spans multiple statements in Python with MySQLdb?

  - by Fast Fish

  I know that with an InnoDB table, transactions are autocommit, however I understand that to mean for a single statement? For example, I want to check if a user exists in a table, and then if it doesn't, create it. However there lies a race condition. I believe using a transaction prior to doing the select, will ensure that the table remains untouched until the subsequent insert, and the transaction is committed. How can you do this with MySQLdb and Python?

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• CorePlot - Set y-Axis range to include all data points

  - by zdestiny

  I have implemented a CorePlot graph in my iOS application, however I am unable to dynamically size the y-Axis based on the data points in the set. Some datasets range from 10-50, while others would range from 400-500. In both cases, I would like to have y-origin (0) visible. I have tried using the scaletofitplots method: [graph.defaultPlotSpace scaleToFitPlots:[graph allPlots]]; but this has no effect on the graphs, they still show the default Y-Axis range of 0 to 1. The only way that I can change the y-Axis is to do it manually via this: graph.defaultPlotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0f)) length:CPTDecimalFromFloat(500.0f)]; however this doesn't work well for graphs with smaller ranges (10-50), as you can imagine. Is there any method to retrieve the highest y-value from my dataset so that I can manually set the maximum y-Axis to that value? Or is there a better alternative?

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• Pass in the object a java class is embedded in as a parameter.

  - by Leif Andersen

  I'm building an android application, which has a list view, and in the list view, a click listener, containing an onItemClick method. So I have something like this: public class myList extends ListActivity { @Override public void onCreate(Bundle savedInstanceState) { getListView().setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View view, int position, long id) { /* Do something*/ } } } Normally, this works fine. However, many times I find myself needing too preform an application using the outer class as a context. thusfar, I've used: parent.getContext(); to do this, but I would like to know, is that a bad idea? I can't really call: super because it's not really a subclass, just an embedded one. So is there any better way, or is that considered cosure? Also, if it is the right way, what should I do if the embedded method doesn't have a parameter to get the outside class? Thank you.

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• Where do all these messages come from?

  - by stacker

  This configuration works fine, but inbound-channel-adapter which is supposed to poll every 15 secs is running continously. Does anyone have an idea what I'm doning wrong? <si:channel id="msgChannel" /> <si:inbound-channel-adapter ref="jdbcInputAdapter" method="fetchData" channel="msgChannel"> <si:poller> <si:interval-trigger interval="15000" /> </si:poller> </si:inbound-channel-adapter> <si:outbound-channel-adapter ref="shouter" method="shout" channel="msgChannel"/>

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