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  • Code Trivia: optimize the code for multiple nested loops

    - by CodeToGlory
    I came across this code today and wondering what are some of the ways we can optimize it. Obviously the model is hard to change as it is legacy, but interested in getting opinions. Changed some names around and blurred out some core logic to protect. private static Payment FindPayment(Order order, Customer customer, int paymentId) { Payment payment = Order.Payments.FindById(paymentId); if (payment != null) { if (payment.RefundPayment == null) { return payment; } if (String.Compare(payment.RefundPayment, "refund", true) != 0 ) { return payment; } } Payment finalPayment = null; foreach (Payment testpayment in Order.payments) { if (testPayment.Customer.Name != customer.Name){continue;} if (testPayment.Cancelled) { continue; } if (testPayment.RefundPayment != null) { if (String.Compare(testPayment.RefundPayment, "refund", true) == 0 ) { continue; } } if (finalPayment == null) { finalPayment = testPayment; } else { if (testPayment.Value > finalPayment.Value) { finalPayment = testPayment; } } } if (finalPayment == null) { return payment; } return finalPayment; } Making this a wiki so code enthusiasts can answer without worrying about points.

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  • Lisp Style question label local functions or not?

    - by Andrew Myers
    I was wondering if there is a standard practice regarding the use of labels in Lisp. I've been messing around with a Lisp implementation of the algorithm described in the first answer here http://stackoverflow.com/questions/352203/generating-permutations-lazily My current version uses labels to break out portions of functionality. (defun next-permutation (pmute) (declare (vector pmute)) (let ((len (length pmute))) (if (> len 2) (labels ((get-pivot () (do ((pivot (1- len) (1- pivot))) ((or (= pivot 0) (< (aref pmute (1- pivot)) (aref pmute pivot))) pivot))) (get-swap (pivot) (let ((swp (1- len))) (loop for i from (1- len) downto pivot do (if (or (and (> (aref pmute i) (aref pmute (1- pivot))) (< (aref pmute i) (aref pmute swp))) (< (aref pmute swp) (aref pmute (1- pivot)))) (setf swp i))) swp)) (next (swp pivot) (rotatef (aref pmute (1- pivot)) (aref pmute swp)) (reverse-vector pmute pivot (1- len)))) (let ((piv (get-pivot))) (if (> piv 0) (next (get-swap piv) piv) nil)))))) Since each label is only called once I was wondering if this is considered bad practice since the only reason to do it in this case is for aesthetic reasons. I would argue that the current version with labels is clearer but that may go against common wisdom that I'm not aware of, being new to Lisp.

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  • Is there any better IDOMImplementation other than MSXML?

    - by Chau Chee Yang
    There are 3 IDOMImplementation available in Delphi: MSXML Xerces XML ADOM XML v4 MSXML is the default IDOMImplementation. My test is count the time need to load a 10MB xml file. I use a Delphi unit generated from a XSD using XML data binding to load the xml file. This unit has 3 common function: function Getmenubar(Doc: IXMLDocument): IXMLMenubarType; function Loadmenubar(const FileName: WideString): IXMLMenubarType; function Newmenubar: IXMLMenubarType; I learn from the web that some comment that MSXML's overhead is high that it doesn't perform if compare to other XML parser. However, my study shows that MSXML is the best among others. Xerces XML 2nd and ADOM XML v4 the worst: MSXML - 0.6410 seconds Xerces XML - 2.4220 seconds ADOM XML v4 - 67.50 seconds I also come across with OmniXML that claim to have much better performance compare to MSXML but I never success using it with the unit generated by XML data binding. Is there any other vendor that implement IDOMImplementation of Delphi that work much better than MSXML? I am using Delphi 2010 and Windows 7.

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  • Dependency Property on ValueConverter

    - by spoon16
    I'm trying to initialize a converter in the Resources section of my UserControl with a reference to one of the objects in my control. When I try to run the application I get an XAML parse exception. XAML: <UserControl.Resources> <converter:PointConverter x:Key="pointConverter" Map="{Binding ElementName=ThingMap}" /> </UserControl.Resources> <Grid> <m:Map x:Name="ThingMap" /> </Grid> Point Converter Class: public class PointConverter : DependencyObject, IValueConverter { public Microsoft.Maps.MapControl.Map Map { get { return (Microsoft.Maps.MapControl.Map)GetValue(MapProperty); } set { SetValue(MapProperty, value); } } // Using a DependencyProperty as the backing store for Map. This enables animation, styling, binding, etc... public static readonly DependencyProperty MapProperty = DependencyProperty.Register("Map", typeof(Microsoft.Maps.MapControl.Map), typeof(PointConverter), null); public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { string param = (string)parameter; Microsoft.Maps.MapControl.Location location = value as Microsoft.Maps.MapControl.Location; if (location != null) { Point point = Map.LocationToViewportPoint(location); if (string.Compare(param.ToUpper(), "X") == 0) return point.X; else if (string.Compare(param.ToUpper(), "Y") == 0) return point.Y; return point; } return null; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } }

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  • theoretical and practical matrix multiplication FLOP

    - by mjr
    I wrote traditional matrix multiplication in c++ and tried to measure and compare its theoretical and practical FLOP. As I know inner loop of MM has 2 operation therefore simple MM theoretical Flops is 2*n*n*n (2n^3) but in practice I get something like 4n^3 + number of operation which is 2 i.e. 6n^3 also if I just try to add up only one array a[i][j]++ practical flops then calculate like 3n^3 and not n^3 as you see again it is 2n^3 +1 operation and not 1 operation * n^3 . This is in case if I use 1D array in three nested loops as Matrix multiplication and compare flop, practical flop is the same (near) the theoretical flop and depend exactly as the number of operation in inner loop.I could not find the reason for this behaviour. what is the reason in both case? I know that theoretical flop is not the same as practical one because of some operations like load etc. system specification: Intel core2duo E4500 3700g memory L2 cache 2M x64 fedora 17 sample results: Matrix matrix multiplication 512*512 Real_time: 1.718368 Proc_time: 1.227672 Total flpops: 807,107,072 MFLOPS: 657.429016 Real_time: 3.608078 Proc_time: 3.042272 Total flpops: 807,024,448 MFLOPS: 265.270355 theoretical flop: 2*512*512*512=268,435,456 Practical flops= 6*512^3 =807,107,072 Using 1 dimensional array float d[size][size]:512 or any size for (int j = 0; j < size; ++j) { for (int k = 0; k < size; ++k) { d[k]=d[k]+e[k]+f[k]+g[k]+r; } } Real_time: 0.002288 Proc_time: 0.002260 Total flpops: 1,048,578 MFLOPS: 464.027161 theroretical flop: *4n^2=4*512^2=1,048,576* practical flop : 4n^2+overhead (other operation?)=1,048,578 3 loop version: Real_time: 1.282257 Proc_time: 1.155990 Total flpops: 536,872,000 MFLOPS: 464.426117 theoretical flop:4n^3 = 536,870,912 practical flop: *4n^3=4*512^3+overheads(other operation?)=536,872,000* thank you

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  • configure.in: AM_DISABLE_SHARED doesn't change my Makefile

    - by t2k32316
    I'm extremely new to using Makefiles and autoconf. I'm using the Camellia image library and trying to statically link my code against their libraries. When I run "make" on the Camellia image library, I get libCamellia.a, .so, .la, and .so.0.0.0 files inside my /usr/local/lib directory. This is the command I use to compile my code with their libraries: gcc -L/usr/local/lib -lCamellia -o myprogram myprogram.c This works fine, but when I try to statically link, this is what I get: gcc -static -L/usr/local/lib -lCamellia -o myprogram myprogram.c /tmp/cck0pw70.o: In function `main': myprogram.c:(.text+0x23): undefined reference to `camLoadPGM' myprogram.c:(.text+0x55): undefined reference to `camAllocateImage' myprogram.c:(.text+0x97): undefined reference to `camZoom2x' myprogram.c:(.text+0x104): undefined reference to `camSavePGM' collect2: ld returned 1 exit status I want to statically link because I'm trying to modify the Camellia source code and I want to compare my version against theirs. So after some googling, I tried adding AM_DISABLE_SHARED into the configure.in file. But after running ./configure, I still get the exact same Makefile. After I "make install", I still get the same results above. What is an easy way to get two versions of my code, one with the original Camellia source code compiled and one with my modified version? I think static libraries should work. There is an easy way to get static libraries working or are there other simple solutions to my problem? I just don't want to re-"make" and re-"make install" everytime I want to compare my version against the original.

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  • What are the primitive Forth operators?

    - by Barry Brown
    I'm interested in implementing a Forth system, just so I can get some experience building a simple VM and runtime. When starting in Forth, one typically learns about the stack and its operators (DROP, DUP, SWAP, etc.) first, so it's natural to think of these as being among the primitive operators. But they're not. Each of them can be broken down into operators that directly manipulate memory and the stack pointers. Later one learns about store (!) and fetch (@) which can be used to implement DUP, SWAP, and so forth (ha!). So what are the primitive operators? Which ones must be implemented directly in the runtime environment from which all others can be built? I'm not interested in high-performance; I want something that I (and others) can learn from. Operator optimization can come later. (Yes, I'm aware that I can start with a Turing machine and go from there. That's a bit extreme.) Edit: What I'm aiming for is akin to bootstrapping an operating system or a new compiler. What do I need do implement, at minimum, so that I can construct the rest of the system out of those primitive building blocks? I won't implement this on bare hardware; as an educational exercise, I'd write my own minimal VM.

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  • Asp.net Login Status Question: It Aint Working

    - by contactmatt
    I'm starting to use Role Management in my website, and I'm current following along on the tutorial from http://www.asp.net/Learn/Security/tutorial-02-vb.aspx . I'm having a problem with the asp:LoginStatus control. It is not telling me that I am currently logged in after a successful login. This can't be true because after successfully logging in, my LoggedInTemplate is shown. The username and passwords are simply stored in a array. Heres the Login.aspx page code. Protected Sub btnLogin_Click(ByVal sender As Object, ByVal e As System.EventArgs) _ Handles btnLogin.Click ' Three valid username/password pairs: Scott/password, Jisun/password, and Sam/password. Dim users() As String = {"Scott", "Jisun", "Sam"} Dim passwords() As String = {"password", "password", "password"} For i As Integer = 0 To users.Length - 1 Dim validUsername As Boolean = (String.Compare(txtUserName.Text, users(i), True) = 0) Dim validPassword As Boolean = (String.Compare(txtPassword.Text, passwords(i), False) = 0) If validUsername AndAlso validPassword Then FormsAuthentication.RedirectFromLoginPage(txtUserName.Text, chkRemember.Checked) End If Next ' If we reach here, the user's credentials were invalid lblInvalid.Visible = True End Sub Here is the content place holder on the master page specifically designed to hold Login Information. On successfull login, the page is redirected to '/Default.aspx', and the LoggedIn Template below is shown...but the status says Log In. <asp:ContentPlaceHolder Id="LoginContent" runat="server"> <asp:LoginView ID="LoginView1" runat="server"> <LoggedInTemplate> Welcome back, <asp:LoginName ID="LoginName1" runat="server" />. </LoggedInTemplate> <AnonymousTemplate> Hello, stranger. </AnonymousTemplate> </asp:LoginView> <br /> <asp:LoginStatus ID="LoginStatus1" runat="server" LogoutAction="Redirect" LogoutPageUrl="~/Logout.aspx" /> </asp:ContentPlaceHolder> Forms authentication is enabled. I'm not sure what to do about this :o.

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  • Implementing A Static NSOutlineView

    - by spamguy
    I'm having a hard time scraping together enough snippets of knowledge to implement an NSOutlineView with a static, never-changing structure defined in an NSArray. This link has been great, but it's not helping me grasp submenus. I'm thinking they're just nested NSArrays, but I have no clear idea. Let's say we have an NSArray inside an NSArray, defined as NSArray *subarray = [[NSArray alloc] initWithObjects:@"2.1", @"2.2", @"2.3", @"2.4", @"2.5", nil]; NSArray *ovStructure = [[NSArray alloc] initWithObjects:@"1", subarray, @"3", nil]; The text is defined in outlineView:objectValueForTableColumn:byItem:. - (id)outlineView:(NSOutlineView *)ov objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)ovItem { if ([[[tableColumn headerCell] stringValue] compare:@"Key"] == NSOrderedSame) { // Return the key for this item. First, get the parent array or dictionary. // If the parent is nil, then that must be root, so we'll get the root // dictionary. id parentObject = [ov parentForItem:ovItem] ? [ov parentForItem:ovItem] : ovStructure; if ([parentObject isKindOfClass:[NSArray class]]) { // Arrays don't have keys (usually), so we have to use a name // based on the index of the object. NSLog([NSString stringWithFormat:@"%@", ovItem]); //return [NSString stringWithFormat:@"Item %d", [parentObject indexOfObject:ovItem]]; return (NSString *) [ovStructure objectAtIndex:[ovStructure indexOfObject:ovItem]]; } } else { // Return the value for the key. If this is a string, just return that. if ([ovItem isKindOfClass:[NSString class]]) { return ovItem; } else if ([ovItem isKindOfClass:[NSDictionary class]]) { return [NSString stringWithFormat:@"%d items", [ovItem count]]; } else if ([ovItem isKindOfClass:[NSArray class]]) { return [NSString stringWithFormat:@"%d items", [ovItem count]]; } } return nil; } The result is '1', '(' (expandable), and '3'. NSLog shows the array starting with '(', hence the second item. Expanding it causes a crash due to going 'beyond bounds.' I tried using parentForItem: but couldn't figure out what to compare the result to. What am I missing?

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  • In a digital photo, how can I detect if a mountain is obscured by clouds?

    - by Gavin Brock
    The problem I have a collection of digital photos of a mountain in Japan. However the mountain is often obscured by clouds or fog. What techniques can I use to detect that the mountain is visible in the image? I am currently using Perl with the Imager module, but open to alternatives. All the images are taken from the exact same position - these are some samples. My naïve solution I started by taking several horizontal pixel samples of the mountain cone and comparing the brightness values to other samples from the sky. This worked well for differentiating good image 1 and bad image 2. However in the autumn it snowed and the mountain became brighter than the sky, like image 3, and my simple brightness test started to fail. Image 4 is an example of an edge case. I would classify this as a good image since some of the mountain is clearly visible. UPDATE 1 Thank you for the suggestions - I am happy you all vastly over-estimated my competence. Based on the answers, I have started trying the ImageMagick edge-detect transform, which gives me a much simpler image to analyze. convert sample.jpg -edge 1 edge.jpg I assume I should use some kind of masking to get rid of the trees and most of the clouds. Once I have the masked image, what is the best way to compare the similarity to a 'good' image? I guess the "compare" command suited for this job? How do I get a numeric 'similarity' value from this?

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  • Should I be relying on WebTests for data validation?

    - by Alexander Kahoun
    I have a suite of web tests created for a web service. I use it for testing a particular input method that updates a SQL Database. The web service doesn't have a way to retrieve the data, that's not its purpose, only to update it. I have a validator that validates the response XML that the web service generates for each request. All that works fine. It was suggested by a teammate that I add data validation so that I check the database to see the data after the initial response validator runs and compare it with what was in the input request. We have a number of services and libraries that are separate from the web service I'm testing that I can use to get the data and compare it. The problem is that when I run the web test the data validation always fails even when the request succeeds. I've tried putting the thread to sleep between the response validation and the data validation but to no avail; It always gets the data from before the response validation. I can set a break point and visually see that the data has been updated in the DB, funny thing is when I step through it in debug with the breakpoint it does validate successfully. Before I get too much more into this issue I have to ask; Is this the purpose of web tests? Should I be able to validate data through service calls in this manner or am I asking too much of a web test and the response validation is as far as I should go?

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  • Comparing developer productivity tools

    - by Jacob
    I am getting ready to test developer productivity tools for our team (Coderush, Resharper, JustCode, etc). We're planning to roll the tool out the same time as we deploy Visual Studio 2010 and TFS. I've seen several posts discussing the merits of one tool versus another. However, I haven't been able to find any discussion of a methodology self evaluating. One approach I've seen is to use each tool for a month or so and decide which one you like best. This seems completely reasonable if I were evaluating it for myself, but since I'm evaluating for others as well, I'd like to do something more rigorous. I'm hoping to collect some ideas on how to do that. As a starting point, my thinking was to come up a list of 10-20 crucial features to compare, then prepare a matrix where I can compare the relative strengths of each product. Once the matrix is complete, we can make a well informed decision about which product aligns with out needs. Since I'm not a user of any product now, it's been difficult to figure out which features are critical and which are less so. Thank you!

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  • C# .NET: Descending comparison of a SortedDictionary?

    - by Rosarch
    I'm want a IDictionary<float, foo> that returns the larges values of the key first. private IDictionary<float, foo> layers = new SortedDictionary<float, foo>(new DescendingComparer<float>()); class DescendingComparer<T> : IComparer<T> where T : IComparable<T> { public int Compare(T x, T y) { return -y.CompareTo(x); } } However, this returns values in order of the smallest first. I feel like I'm making a stupid mistake here. Just to see what would happen, I removed the - sign from the comparator: public int Compare(T x, T y) { return y.CompareTo(x); } But I got the same result. This reinforces my intuition that I'm making a stupid error. This is the code that accesses the dictionary: foreach (KeyValuePair<float, foo> kv in sortedLayers) { // ... } UPDATE: This works, but is too slow to call as frequently as I need to call this method: IOrderedEnumerable<KeyValuePair<float, foo>> sortedLayers = layers.OrderByDescending(kv => kv.Key); foreach (KeyValuePair<float, ICollection<IGameObjectController>> kv in sortedLayers) { // ... } UPDATE: I put a break point in the comparator that never gets hit as I add and remove kv pairs from the dictionary. What could this mean?

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  • Comparing two collections for equality

    - by Crossbrowser
    I would like to compare two collections (in C#), but I'm not sure of the best way to implement this efficiently. I've read the other thread about Enumerable.SequenceEqual, but it's not exactly what I'm looking for. In my case, two collections would be equal if they both contain the same items (no matter the order). Example: collection1 = {1, 2, 3, 4}; collection2 = {2, 4, 1, 3}; collection1 == collection2; // true What I usually do is to loop through each item of one collection and see if it exists in the other collection, then loop through each item of the other collection and see if it exists in the first collection. (I start by comparing the lengths). if (collection1.Count != collection2.Count) return false; // the collections are not equal foreach (Item item in collection1) { if (!collection2.Contains(item)) return false; // the collections are not equal } foreach (Item item in collection2) { if (!collection1.Contains(item)) return false; // the collections are not equal } return true; // the collections are equal However, this is not entirely correct, and it's probably not the most efficient way to do compare two collections for equality. An example I can think of that would be wrong is: collection1 = {1, 2, 3, 3, 4} collection2 = {1, 2, 2, 3, 4} Which would be equal with my implementation. Should I just count the number of times each item is found and make sure the counts are equal in both collections? The examples are in some sort of C# (let's call it pseudo-C#), but give your answer in whatever language you wish, it does not matter. Note: I used integers in the examples for simplicity, but I want to be able to use reference-type objects too (they do not behave correctly as keys because only the reference of the object is compared, not the content).

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  • Comparing UIColors or CGColor or CGColorSpace

    - by wiznaibus
    I'm having an issue comparing UIColors. I have an image, which I have successfully extracted the color on the image at which the user clicked. Now I want to compare that color with other colors, but I'm getting some strange results. Here's what I've tried: CGColorRef pixelColor = [[buttonImage colorAtPixel:point] CGColor]; UIColor* color = [UIColor colorWithCGColor:pixelColor]; UIColor* aqua = [UIColor colorWithRed:0.521569 green:0.768627 blue:0.254902 alpha:1]; if (CGColorEqualToColor(color.CGColor, aqua.CGColor)) { DLog(@"Apparently, it works"); } DLog(@"%@", color.CGColor); DLog(@"%@", aqua.CGColor); Output: 2011-05-21 19:48:27.144 Coffee[66860:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d1eb80> [<CGColorSpace 0x4d1a070> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) 2011-05-21 19:48:27.145 Coffee[66860:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d1f750> [<CGColorSpace 0x4d1a070> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) It looks like the CGColor addresses are different, but the CGColorSpaces are the same, but I can't figure out how to compare the CGColorSpaces I've also tried this: CGColorRef pixelColor = [[buttonImage colorAtPixel:point] CGColor]; UIColor* color = [UIColor colorWithCGColor:pixelColor]; UIColor* aqua = [UIColor colorWithRed:0.521569 green:0.768627 blue:0.254902 alpha:1]; if ([color isEqual:aqua]) { DLog(@"Apparently, it works"); } DLog(@"%@", color.CGColor); DLog(@"%@", aqua.CGColor); The same silliness occurs. 2011-05-21 20:02:49.277 Coffee[67013:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d3b810> [<CGColorSpace 0x5912010> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) 2011-05-21 20:02:49.278 Coffee[67013:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d3ba20> [<CGColorSpace 0x5912010> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 )`

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  • MS SQL datetime precision problem

    - by Nailuj
    I have a situation where two persons might work on the same order (stored in an MS SQL database) from two different computers. To prevent data loss in the case where one would save his copy of the order first, and then a little later the second would save his copy and overwrite the first, I've added a check against the lastSaved field (datetime) before saving. The code looks roughly like this: private bool orderIsChangedByOtherUser(Order localOrderCopy) { // Look up fresh version of the order from the DB Order databaseOrder = orderService.GetByOrderId(localOrderCopy.Id); if (databaseOrder != null && databaseOrder.LastSaved > localOrderCopy.LastSaved) { return true; } else { return false; } } This works for most of the time, but I have found one small bug. If orderIsChangedByOtherUser returns false, the local copy will have its lastSaved updated to the current time and then be persisted to the database. The value of lastSaved in the local copy and the DB should now be the same. However, if orderIsChangedByOtherUser is run again, it sometimes returns true even though no other user has made changes to the DB. When debugging in Visual Studio, databaseOrder.LastSaved and localOrderCopy.LastSaved appear to have the same value, but when looking closer they some times differ by a few milliseconds. I found this article with a short notice on the millisecond precision for datetime in SQL: Another problem is that SQL Server stores DATETIME with a precision of 3.33 milliseconds (0. 00333 seconds). The solution I could think of for this problem, is to compare the two datetimes and consider them equal if they differ by less than say 10 milliseconds. My question to you is then: are there any better/safer ways to compare two datetime values in MS SQL to see if they are exactly the same?

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  • List.Sort in C#: comparer being called with null object

    - by cbp
    I am getting strange behaviour using the built-in C# List.Sort function with a custom comparer. For some reason it sometimes calls the comparer class's Compare method with a null object as one of the parameters. But if I check the list with the debugger there are no null objects in the collection. My comparer class looks like this: public class DelegateToComparer<T> : IComparer<T> { private readonly Func<T,T,int> _comparer; public int Compare(T x, T y) { return _comparer(x, y); } public DelegateToComparer(Func<T, T, int> comparer) { _comparer = comparer; } } This allows a delegate to be passed to the List.Sort method, like this: mylist.Sort(new DelegateToComparer<MyClass>( (x, y) => { return x.SomeProp.CompareTo(y.SomeProp); }); So the above delegate will throw a null reference exception for the x parameter, even though no elements of mylist are null. UPDATE: Yes I am absolutely sure that it is parameter x throwing the null reference exception! UPDATE: Instead of using the framework's List.Sort method, I tried a custom sort method (i.e. new BubbleSort().Sort(mylist)) and the problem went away. As I suspected, the List.Sort method passes null to the comparer for some reason.

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  • Iterating through String word at a time in Python

    - by AlgoMan
    I have a string buffer of a huge text file. I have to search a given words/phrases in the string buffer. Whats the efficient way to do it ? I tried using re module matches. But As i have a huge text corpus that i have to search through. This is taking large amount of time. Given a Dictionary of words and Phrases. I iterate through the each file, read that into string , search all the words and phrases in the dictionary and increment the count in the dictionary if the keys are found. One small optimization that we thought was to sort the dictionary of phrases/words with the max number of words to lowest. And then compare each word start position from the string buffer and compare the list of words. If one phrase is found, we don search for the other phrases (as it matched the longest phrase ,which is what we want) Can some one suggest how to go about word by word in the string buffer. (Iterate string buffer word by word) ? Also, Is there any other optimization that can be done on this ?

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  • Overriding equals method without breaking symmetry in a class that has a primary key

    - by Kosta
    Hi, the answer to this question is probably "not possible", but let me ask regardless :) Assuming we have a very simple JAVA class that has a primary key, for example: class Person { String ssid; String name; String address; ... } Now, I want to store people in a collection, meaning I will have to override the equals method. Not a completely trivial matter, but on a bare basis I will have something along the lines of: @Override public boolean equals (Object other) { if(other==this) return true; if(!other.getClass().equals(this.getClass()) return false; Person otherPerson = (Person)other; if(this.ssid.equals(otherPerson.getSsid()) return true; } Excuse any obvious blunders, just typing this out of my head. Now, let's say later on in the application I have a ssid I obtained through user input. If I want to compare my ssid to a Person, I would have to call something like: String mySsid = getFromSomewhere(); Person myPerson = getFromSomewhere(); if(myPerson.equals(new Person(mySsid)) doSomething(); This means I have to create a convenience constructor to create a Person based on ssid (if I don't already have one), and it's also quite verbose. It would be much nicer to simply call myPerson.equals(mySsid) but if I added a string comparison to my Person equals class, that would break the symmetry property, since the String hasn't got a clue on how to compare itself to a Person. So finally, the big question, is there any way to enable this sort of "shorthand" comparisons using the overriden equals method, and without breaking the symmetry rule? Thanks for any thoughts on this!

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  • Optimize Use of Ramdisk for Eclipse Development

    - by Eric J.
    We're developing Java/SpringSource applications with Eclipse on 32-bit Vista machines with 4GB RAM. The OS exposes roughly 3.3GB of RAM due to reservations for hardware etc. in the virtual address space. I came across several Ramdisk drivers that can create a virtual disk from the OS-hidden RAM and am looking for suggestions how best to use the 740MB virtual disk to speed development in our environment. The slowest part of development for us is compiling as well as launching SpringSource dm Server. One option is to configure Vista to swap to the Ramdisk. That works, and noticeably speeds up development in low memory situations. However, the 3.3GB available to the OS is often sufficient and there are many situations where we do not use the swap file(s) much. Another option is to use the Ramdisk as a location for temporary files. Using the Vista mklink command, I created a hard link from where the SpringSource dm Server's work area normally resides to the Ramdisk. That significantly improves server startup times but does nothing for compile times. There are roughly 500MB still free on the Ramdisk when the work directory is fully utilized, so room for plenty more. What other files/directories might be candidates to place on the Ramdisk? Eclipse-related files? (Parts of) the JDK? Is there a free/open source tool for Vista that will show me which files are used most frequently during a period of time to reduce the guesswork?

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  • Convert a Unit Vector to a Quaternion

    - by Hmm
    So I'm very new to quaternions, but I understand the basics of how to manipulate stuff with them. What I'm currently trying to do is compare a known quaternion to two absolute points in space. I'm hoping what I can do is simply convert the points into a second quaternion, giving me an easy way to compare the two. What I've done so far is to turn the two points into a unit vector. From there I was hoping I could directly plug in the i j k into the imaginary portion of the quaternion with a scalar of zero. From there I could multiply one quaternion by the other's conjugate, resulting in a third quaternion. This third quaternion could be converted into an axis angle, giving me the degree by which the original two quaternions differ by. Is this thought process correct? So it should just be [ 0 i j k ]. I may need to normalize the quaternion afterwards, but I'm not sure about that. I have a bad feeling that it's not a direct mapping from a vector to a quaternion. I tried looking at converting the unit vector to an axis angle, but I'm not sure this would work, since I don't know what angle to give as an input.

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  • Setting up Mercurial/TortoiseHg to work with UltraCompare

    - by Tim Pietzcker
    Hi, I'm trying to get my favorite Windows diff/merge tool, UltraCompare (V7.00) to work with Mercurial/TortoiseHg. I have set up UltraCompare in my Mercurial.ini like this (only relevant bits shown): [merge-tools] UltraCompare.executable = C:\Programme\IDM Computer Solutions\UltraCompare\uc.com UltraCompare.args = $base $local $other UltraCompare.priority = 1 UltraCompare.gui = True UltraCompare.binary = True UltraCompare.checkconflicts = True UltraCompare.checkchanged = True However, the three-way-merge fails. The path names get messed up if the path to the repository that is being merged to contains a space. I have done some more testing, and I've found out (using Process Explorer) that uc.com is called with a broken command line if there is a space in the repository's path: Compare "C:\Programme\IDM Computer Solutions\UltraCompare\uc.exe" " "c:\dokume~1\tim~1.pie\lokale~1\temp\test.txt~base.akr6au" "E:\Eigene Dateien\test\test-merge\test.txt" "c:\dokume~1\tim~1.pie\lokale~1\temp\test.txt~other.b92442" and "C:\Programme\IDM Computer Solutions\UltraCompare\uc.com" "c:\dokume~1\tim~1.pie\lokale~1\temp\test.txt~base.e7vryp" "E:\test\test-merge\test.txt" "c:\dokume~1\tim~1.pie\lokale~1\temp\test.txt~other.u_qxme" There is an extraneous " after the path of the executable in the first example - not in the second (which works fine). To me, it seems as if UltraCompare is doing everything right, and that Mercurial/TortoiseHg are passing a defective command line to it. Would you say so, too? Is there a workaround? I've just updated to Mercurial 1.5/TortoiseHg 1.0, and the problem persists. Support for other merge tools (Beyond Compare and others) has been added, sadly not UltraCompare...

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  • Generic C# Class: Set "Generic" Property

    - by BlaM
    I'm quite new to C#, so I might have a problem that C# has a simple solution for. I have a generic class with a property of "generic" type. I want to have a function to set that property, but I need to convert it to do so. public class BIWebServiceResult<T> { public T Data; public delegate StatusCode StringToStatusCode(string Input); public void SetData(string Input, StringToStatusCode StringToError) { if (StringToError(Input) == 0) { if (Data is string[]) { Data = new string[1]; Data[0] = Input; } else if (Data is string) { Data = Input; } else if (Data is bool) { Data = DetectBool(Input); } } } private bool DetectBool(string Compare) { return Compare == "true"; } } The problem with that approach is, that it does not work :) (No that's not all code, just a snippet to show what my problem is) It doesn't even compile, because "Data = new string[]" can't work if Data is - for example - boolean. How do I implement a function that behaves differently depending on the type of my generic property?

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  • Fixing color in scatter plots in matplotlib

    - by ajhall
    Hi guys, I'm going to have to come back and add some examples if you need them, which you might. But, here's the skinny- I'm plotting scatter plots of lab data for my research. I need to be able to visually compare the scatter plots from one plot to the next, so I want to fix the color range on the scatter plots and add in a colorbar to each plot (which will be the same in each figure). Essentially, I'm fixing all aspects of the axes and colorspace etc. so that the plots are directly comparable by eye. For the life of me, I can't seem to get my scatter() command to properly set the color limits in the colorspace (default)... i.e., I figure out my total data's min and total data's max, then apply them to vmin, vmax, for the subset of data, and the color still does not come out properly in both plots. This must come up here and there, I can't be the only one that wants to compare various subsets of data amongst plots... so, how do you fix the colors so that each data keeps it's color between plots and doesn't get remapped to a different color due to the change in max/min of the subset -v- the whole set? I greatly appreciate all your thoughts!!! A mountain-dew and fiery-hot cheetos to all! -Allen

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  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

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