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  • Good software to record desktop/screen operations [closed]

    - by juanmaflyer
    Possible Duplicate: What is the best software for desktop recording? Hi superuser's. I would like to record some tasks in a program (i want to make a video where i will be explaining how to use a particular program) and i haven't found a good software to do it yet... I have just tested camStudio but when i hit the Record Button the computer starts working very slowly (even when recording in a small area... so i wouldn't imagine how slow it will run if recording full screen). So i want you to recommend me some good software to record the screen on a fast way... Thanks a lot. Juan

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  • Logfile software for making querys, extracting and other operations

    - by Juw
    I have written an app that connects to a server IIS 6 to retrieve information. When doing this i have collected data (phone model etc) and send it to the server with a regular GET HTTP call like this: http://www.myserver.com/getData.php?phonemodel=userphone&appversion=2&id=20 This is logged in the IIS logfiles. I thought of writing my own parser for log files. But why invent the wheel? I´m looking for a software that can read the IIS 6 logfiles. I would like it to be able to do: Extraction - Extract all lines that contains: www.myserver.com/getData Filtering - View all lines where http-code is not 200 Queries - View all lines where phonemodel=iphone Any tips on free software that can help me with this? Thanx in advance!

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  • Encrypted directory makes file operations for whole disk very slow

    - by user1566277
    I am running an arm GNU/Linux and I have a SD-Card with three partitions on it. On one of the Partition I create an encfs file and then mount it on a directory which is in another partition to make that directory encrypted. Works fine. But now the writing speed on all the partitions are reduced drastically. I can understand that it should be slow for encrypted directory but why the its reducing write speed for all the partitions. E.g., if do not mount the encrypted directory 20MB is transferred in 2 Sec. roughly but with the encrypted directory mounted its like 20 Seconds for same file. I am using LUKS and all the partitons are ext3 except for the directory where /dev/mapper/encfs is mounted as type ext2. Any hints?

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  • CSG operations on implicit surfaces with marching cubes [SOLVED]

    - by Mads Elvheim
    I render isosurfaces with marching cubes, (or perhaps marching squares as this is 2D) and I want to do set operations like set difference, intersection and union. I thought this was easy to implement, by simply choosing between two vertex scalars from two different implicit surfaces, but it is not. For my initial testing, I tried with two spheres circles, and the set operation difference. i.e A - B. One circle is moving and the other one is stationary. Here's the approach I tried when picking vertex scalars and when classifying corner vertices as inside or outside. The code is written in C++. OpenGL is used for rendering, but that's not important. Normal rendering without any CSG operations does give the expected result. void march(const vec2& cmin, //min x and y for the grid cell const vec2& cmax, //max x and y for the grid cell std::vector<vec2>& tri, float iso, float (*cmp1)(const vec2&), //distance from stationary circle float (*cmp2)(const vec2&) //distance from moving circle ) { unsigned int squareindex = 0; float scalar[4]; vec2 verts[8]; /* initial setup of the grid cell */ verts[0] = vec2(cmax.x, cmax.y); verts[2] = vec2(cmin.x, cmax.y); verts[4] = vec2(cmin.x, cmin.y); verts[6] = vec2(cmax.x, cmin.y); float s1,s2; /********************************** ********For-loop of interest****** *******Set difference between **** *******two implicit surfaces****** **********************************/ for(int i=0,j=0; i<4; ++i, j+=2){ s1 = cmp1(verts[j]); s2 = cmp2(verts[j]); if((s1 < iso)){ //if inside circle1 if((s2 < iso)){ //if inside circle2 scalar[i] = s2; //then set the scalar to the moving circle } else { scalar[i] = s1; //only inside circle1 squareindex |= (1<<i); //mark as inside } } else { scalar[i] = s1; //inside neither circle } } if(squareindex == 0) return; /* Usual interpolation between edge points to compute the new intersection points */ verts[1] = mix(iso, verts[0], verts[2], scalar[0], scalar[1]); verts[3] = mix(iso, verts[2], verts[4], scalar[1], scalar[2]); verts[5] = mix(iso, verts[4], verts[6], scalar[2], scalar[3]); verts[7] = mix(iso, verts[6], verts[0], scalar[3], scalar[0]); for(int i=0; i<10; ++i){ //10 = maxmimum 3 triangles, + one end token int index = triTable[squareindex][i]; //look up our indices for triangulation if(index == -1) break; tri.push_back(verts[index]); } } This gives me weird jaggies: It looks like the CSG operation is done without interpolation. It just "discards" the whole triangle. Do I need to interpolate in some other way, or combine the vertex scalar values? I'd love some help with this. A full testcase can be downloaded HERE EDIT: Basically, my implementation of marching squares works fine. It is my scalar field which is broken, and I wonder what the correct way would look like. Preferably I'm looking for a general approach to implement the three set operations I discussed above, for the usual primitives (circle, rectangle/square, plane)

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  • Manipulating matrix operations (transpose, negation, addition, and mutiplication) using functions in

    - by user292489
    I was trying to manipulate matrices in my input file using functions. My input file is: A 3 3 1 2 3 4 5 6 7 8 9 B 3 3 1 0 0 0 1 0 0 0 1 C 2 3 3 5 8 -1 -2 -3 D 3 5 0 0 0 1 0 1 0 1 0 1 0 1 0 0 1 E 1 1 10 F 3 10 1 0 2 0 3 0 4 0 5 0 0 2 3 -1 -3 -4 -3 8 3 7 0 0 0 4 6 5 8 2 -1 10 I am having trouble in implementing the functions that I declared. I assumed my program will perform those operations: transpose, negate, add, and multiply matices according to the users choice: /* once this program is compiled and executed, it will perform the basic matrix * operations: negation, transpose, addition, and multiplication. */ #include <stdio.h> #include <stdlib.h> #define MAX 10 int readmatrix(FILE *input, char martixname[6],int , mat[10][10], int i, int j); void printmatrix(char matrixname[6], int mat[10][10], int i, int j); void Negate(char matrixname[6], int mat[10][10], int i, int j); void add(char matrixname[6], int mat[10][10],int i, int k); void multiply(char matrixname[], int mat[][10], char A[], int i, int k); void transpose (char matrixname[], int mat[][10], char A[], int); void printT(int mat[][10], int); int selctoption(); char selectmatrix(); int main(int argc, char *argv[]) { char matrixtype[6]; int mat[][10]; FILE *filein; int size; int optionop; int matrixop; int option; if (argc != 2) { printf("Usage: executable input.\n"); exit(0); } filein = fopen(argv[1], "r"); if (!filein) { printf("ERROR: input file not found.\n"); exit (0); } size = readmatrix (filein, matrixtype); printmatrix(matrix[][10], size); option = selectoption(); matrixtype = selectmatrix(); //printf("You have: %5.2f ", deposit); optionop = readmatrix(option, matrix[][10], size); if (choiceop == 6) { printf("Thanks for using the matrix operation program.\n"); exit(0); } printf("Please select from the following matrix operations:\n") printf("\t1. Print matrix\n"); printf("\t2. Negate matrix\n"); printf("\t3. Transpose matrix\n"); printf("\t4. Add matrices\n"); printf("\t5. Multiply matrices\n"); printf("\t6. Quit\n"); fclose(filein); return 0; } do { printf("Please select option(1-%d):", optionop); scanf("%d", &matrixop); } while(matrixop <= 0 || matrixop > optionop); void readmatrix (FILE *in, int mat[][10], char A[], int i, int j) { int i=0,j = 0; while (fscanf(in, "%d", &mat[i][j]) != EOF) return 0; } // I would appreciate anyone's feedback.

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  • Is it possible to implement bitwise operators using integer arithmetic?

    - by Statement
    Hello World! I am facing a rather peculiar problem. I am working on a compiler for an architecture that doesn't support bitwise operations. However, it handles signed 16 bit integer arithmetics and I was wondering if it would be possible to implement bitwise operations using only: Addition (c = a + b) Subtraction (c = a - b) Division (c = a / b) Multiplication (c = a * b) Modulus (c = a % b) Minimum (c = min(a, b)) Maximum (c = max(a, b)) Comparisons (c = (a < b), c = (a == b), c = (a <= b), et.c.) Jumps (goto, for, et.c.) The bitwise operations I want to be able to support are: Or (c = a | b) And (c = a & b) Xor (c = a ^ b) Left Shift (c = a << b) Right Shift (c = a b) (All integers are signed so this is a problem) Signed Shift (c = a b) One's Complement (a = ~b) (Already found a solution, see below) Normally the problem is the other way around; how to achieve arithmetic optimizations using bitwise hacks. However not in this case. Writable memory is very scarce on this architecture, hence the need for bitwise operations. The bitwise functions themselves should not use a lot of temporary variables. However, constant read-only data & instruction memory is abundant. A side note here also is that jumps and branches are not expensive and all data is readily cached. Jumps cost half the cycles as arithmetic (including load/store) instructions do. On other words, all of the above supported functions cost twice the cycles of a single jump. Some thoughts that might help: I figured out that you can do one's complement (negate bits) with the following code: // Bitwise one's complement b = ~a; // Arithmetic one's complement b = -1 - a; I also remember the old shift hack when dividing with a power of two so the bitwise shift can be expressed as: // Bitwise left shift b = a << 4; // Arithmetic left shift b = a * 16; // 2^4 = 16 // Signed right shift b = a >>> 4; // Arithmetic right shift b = a / 16; For the rest of the bitwise operations I am slightly clueless. I wish the architects of this architecture would have supplied bit-operations. I would also like to know if there is a fast/easy way of computing the power of two (for shift operations) without using a memory data table. A naive solution would be to jump into a field of multiplications: b = 1; switch (a) { case 15: b = b * 2; case 14: b = b * 2; // ... exploting fallthrough (instruction memory is magnitudes larger) case 2: b = b * 2; case 1: b = b * 2; } Or a Set & Jump approach: switch (a) { case 15: b = 32768; break; case 14: b = 16384; break; // ... exploiting the fact that a jump is faster than one additional mul // at the cost of doubling the instruction memory footprint. case 2: b = 4; break; case 1: b = 2; break; }

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  • 48-bit bitwise operations in Javascript?

    - by randomhelp
    I've been given the task of porting Java's Java.util.Random() to JavaScript, and I've run across a huge performance hit/inaccuracy using bitwise operators in Javascript on sufficiently large numbers. Some cursory research states that "bitwise operators in JavaScript are inherently slow," because internally it appears that JavaScript will cast all of its double values into signed 32-bit integers to do the bitwise operations (see https://developer.mozilla.org/En/Core_JavaScript_1.5_Reference/Operators/Bitwise_Operators for more on this.) Because of this, I can't do a direct port of the Java random number generator, and I need to get the same numeric results as Java.util.Random(). Writing something like this.next = function(bits) { if (!bits) { bits = 48; } this.seed = (this.seed * 25214903917 + 11) & ((1 << 48) - 1); return this.seed >>> (48 - bits); }; (which is an almost-direct port of the Java.util.Random()) code won't work properly, since Javascript can't do bitwise operations on an integer that size.) I've figured out that I can just make a seedable random number generator in 32-bit space using the Lehmer algorithm, but the trick is that I need to get the same values as I would with Java.util.Random(). What should I do to make a faster, functional port?

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  • C# WPF DataBind boolean

    - by jtdangelo
    I have been using this website to learn a lot about C# for a while, but this is my first time posting a question. I look forward to hearing back from some of the seasoned C# veterans! I have been working on a C# 4.0 WPF project and need to figure out how to databind a boolean value. I have a reference to my Application.Current object in a window. My "App" object contains a boolean field called "Downloaded" that is true if the user has downloaded information from a web service. I need to databind a textbox's IsEnabled field to this Downloaded value. Any tips? Here is what I have come up with so far. (Any useful links to better learn WPF XAML are greatly appreciated!) C# Code: class MainWindow : Window { ... private App MyApp = App.Current as App; ... } XAML: <TextBox ... IsEnabled="{Binding Source=MyApp, Path=Downloaded}" /> James

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  • Lightweight spinlocks built from GCC atomic operations?

    - by Thomas
    I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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  • debugging scaffolding contingent upon degbugging boolean (java)

    - by David
    Recently i've found myself writing a lot of methods with what i can only think to call debugging scaffolding. Here's an example: public static void printArray (String[] array, boolean bug) { for (int i = 0; i<array.lenght; i++) { if (bug) System.out.print (i) ; //this line is what i'm calling the debugging scaffolding i guess. System.out.println(array[i]) ; } } in this method if i set bug to true, wherever its being called from maybe by some kind of user imput, then i get the special debugging text to let me know what index the string being printed as at just in case i needed to know for the sake of my debugging (pretend a state of affairs exists where its helpful). All of my questions more or less boil down to the question: is this a good idea? but with a tad bit more objectivity: Is this an effective way to test my methods and debug them? i mean effective in terms of efficiency and not messing up my code. Is it acceptable to leave the if (bug) stuff ; code in place after i've got my method up and working? (if a definition of "acceptability" is needed to make this question objective then use "is not a matter of programing controversy such as ommiting brackets in an if(boolean) with only one line after it, though if you've got something better go ahead and use your definition i won't mind) Is there a more effective way to accomplish the gole of making debugging easier than what i'm doing? Anything you know i mean to ask but that i have forgotten too (as much information as makes sense is appreciated).

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  • Atomic operations on several transactionless external systems

    - by simendsjo
    Say you have an application connecting 3 different external systems. You need to update something in all 3. In case of a failure, you need to roll back the operations. This is not a hard thing to implement, but say operation 3 fails, and when rolling back, the rollback for operation 1 fails! Now the first external system is in an invalid state... I'm thinking a possible solution is to shut down the application and forcing a manual fix of the external system, but then again... It might already have used this information (and perhaps that's why it failed), or we might not have sufficient access. Or it might not even be a good way to rollback the action! Are there some good ways of handling such cases? EDIT: Some application details.. It's a multi user web application. Most of the work is done with scheduled jobs (through Quartz.Net), so most operations is run in it's own thread. Some user actions should trigger jobs that update several systems though. The external systems are somewhat unstable. I Was thinking of changing the application to use the Command and Unit Of Work pattern

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  • Weird exception: Cannot cast String to Boolean when using getBoolean

    - by La bla bla
    I'm getting a very weird error. I have 2 activities. On both I'm getting the SharedPreferences using MODE_PRIVATE (if it matters) by sp = getPreferences(MODE_PRIVATE); on each activity's onCreate() I'm calling sp.getBoolean(IntroActivity.SHOW_INTRO, true) On the IntroActivity this works fine. But when I'm trying in the main activity, I'm getting this 10-12 04:55:23.208: E/AndroidRuntime(11668): FATAL EXCEPTION: main 10-12 04:55:23.208: E/AndroidRuntime(11668): java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.app.SharedPreferencesImpl.getBoolean(SharedPreferencesImpl.java:242) 10-12 04:55:23.208: E/AndroidRuntime(11668): at com.lablabla.parkme.ParkMeActivity$2.onClick(ParkMeActivity.java:194) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.view.View.performClick(View.java:4084) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.view.View$PerformClick.run(View.java:16966) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Handler.handleCallback(Handler.java:615) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Handler.dispatchMessage(Handler.java:92) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Looper.loop(Looper.java:137) 10-12 04:55:23.208: E/AndroidRuntime(11668): at android.app.ActivityThread.main(ActivityThread.java:4745) 10-12 04:55:23.208: E/AndroidRuntime(11668): at java.lang.reflect.Method.invokeNative(Native Method) 10-12 04:55:23.208: E/AndroidRuntime(11668): at java.lang.reflect.Method.invoke(Method.java:511) 10-12 04:55:23.208: E/AndroidRuntime(11668): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 10-12 04:55:23.208: E/AndroidRuntime(11668): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 10-12 04:55:23.208: E/AndroidRuntime(11668): at dalvik.system.NativeStart.main(Native Method) I made sure that I'm not putting a String somewhere in the middle with that same key Any ideas? Thanks! EDIT: some code: //onCreate() sp = getPreferences(MODE_PRIVATE); // other method boolean showIntro = sp.getBoolean(IntroActivity.SHOW_INTRO, true); // Exception is here showIntroCheckBox.setChecked(showIntro); If it matters, the code which throws the exception is inside a button's onClick

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  • Azure batch operations delete several blobs and tables

    - by reft
    I have a function that deletes every table & blob that belongs to the affected user. CloudTable uploadTable = CloudStorageServices.GetCloudUploadsTable(); TableQuery<UploadEntity> uploadQuery = uploadTable.CreateQuery<UploadEntity>(); List<UploadEntity> uploadEntity = (from e in uploadTable.ExecuteQuery(uploadQuery) where e.PartitionKey == "uploads" && e.UserName == User.Idendity.Name select e).ToList(); foreach (UploadEntity uploadTableItem in uploadEntity) { //Delete table TableOperation retrieveOperationUploads = TableOperation.Retrieve<UploadEntity>("uploads", uploadTableItem.RowKey); TableResult retrievedResultUploads = uploadTable.Execute(retrieveOperationUploads); UploadEntity deleteEntityUploads = (UploadEntity)retrievedResultUploads.Result; TableOperation deleteOperationUploads = TableOperation.Delete(deleteEntityUploads); uploadTable.Execute(deleteOperationUploads); //Delete blob CloudBlobContainer blobContainer = CloudStorageServices.GetCloudBlobsContainer(); CloudBlockBlob blob = blobContainer.GetBlockBlobReference(uploadTableItem.BlobName); blob.Delete(); } Each table got its own blob, so if the list contains 3 uploadentities, the 3 table and the 3 blobs will be deleted. I heard you can use table batch operations for reduce cost and load. I tried it, but failed miserable. Anyone intrested in helping me:)? Im guessing tablebatch operations are for tables only, so its a no go for blobs, right? How would you add tablebatchoperations for this code? Do you see any other improvements that can be done? Thanks!

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  • When to define SDD operations System->Actor?

    - by devoured elysium
    I am having some trouble understanding how to make SDDs, as I don't fully grasp why in some cases one should define operations for System - Actor and in others don't. Here is an example: 1) The User tells the System that wants to buy some tickets, stating his client number. 2) The System confirms that the given client number is valid. 3) The User tells the System the movie that wants to see. 4) The System shows the set of available sessions and seats for that movie. 5) The System asks the user which session/seat he wants. 6) The user tells the System the chosen session/seat. This would be converted to: a) -----> tellClientNumber(clientNumber) b) <----- validClientNumber c) -----> tellMovieToSee(movie) d) <----- showsAvailableSeatsHours e) -----> tellSystemChosenSessionSeat(session, seat) I know that when we are dealing with SDD's we are still far away from coding. But I can't help trying to imagine how it how it would have been had I to convert it right away to code: I can understand 1) and 2). It's like if it was a C#/Java method with the following signature: boolean tellClientNumber(clientNumber) so I put both on the SDD. Then, we have the pair 3) 4). I can imagine that as something as: SomeDataStructureThatHoldsAvailableSessionsSeats tellSystemMovieToSee(movie) Now, the problem: From what I've come to understand, my lecturer says that we shouldn't make an operation on the SDD for 5) as we should only show operations from the Actor to the System and when the System is either presenting us data (as in c)) or validating sent data (such as in b)). I find this odd, as if I try to imagine this like a DOS app where you have to put your input sequencially, it makes sense to make an arrow even for 5). Why is this wrong? How should I try to visualize this? Thanks

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  • lua metatable __lt __le __eq forced boolean conversion of return value

    - by chris g.
    Overloading __eq, __lt, and __le in a metatable always converts the returning value to a boolean. Is there a way to access the actual return value? This would be used in the following little lua script to create an expression tree for an argument usage: print(_.a + _.b - _.c * _.d + _.a) -> prints "(((a+b)-(c*d))+a)" which is perfectly what I would like to have but it doesn't work for print(_.a == _.b) since the return value gets converted to a boolean ps: print should be replaced later with a function processing the expression tree -- snip from lua script -- function binop(op1,op2, event) if op1[event] then return op1[event](op1, op2) end if op2[event] then return op2[event](op1, op2) end return nil end function eq(op1, op2)return binop(op1,op2, "eq") end ... function div(op1, op2)return binop(op1,op2, "div") end function exprObj(tostr) expr = { eq = binExpr("=="), lt = binExpr("<"), le = binExpr("<="), add = binExpr("+"), sub=binExpr("-"), mul = binExpr("*"), div= binExpr("/") } setmetatable(expr, { __eq = eq, __lt = lt, __le = le, __add = add, __sub = sub, __mul = mul, __div = div, __tostring = tostr }) return expr end function binExpr(exprType) function binExprBind(lhs, rhs) return exprObj(function(op) return "(" .. tostring(lhs) .. exprType .. tostring(rhs) .. ")" end) end return binExprBind end function varExpr(obj, name) return exprObj(function() return name end) end _ = {} setmetatable(_, { __index = varExpr }) -- snap -- Modifing the lua vm IS an option, however it would be nice if I could use an official release

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  • Python: Behavior of object in set operations

    - by Josh Arenberg
    I'm trying to create a custom object that behaves properly in set operations. I've generally got it working, but I want to make sure I fully understand the implications. In particular, I'm interested in the behavior when there is additional data in the object that is not included in the equal / hash methods. It seems that in the 'intersection' operation, it returns the set of objects that are being compared to, where the 'union' operations returns the set of objects that are being compared. To illustrate: class MyObject: def __init__(self,value,meta): self.value = value self.meta = meta def __eq__(self,other): if self.value == other.value: return True else: return False def __hash__(self): return hash(self.value) a = MyObject('1','left') b = MyObject('1','right') c = MyObject('2','left') d = MyObject('2','right') e = MyObject('3','left') print a == b # True print a == c # False for i in set([a,c,e]).intersection(set([b,d])): print "%s %s" % (i.value,i.meta) #returns: #1 right #2 right for i in set([a,c,e]).union(set([b,d])): print "%s %s" % (i.value,i.meta) #returns: #1 left #3 left #2 left Is this behavior documented somewhere and deterministic? If so, what is the governing principle?

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  • how to use q.js promises to work with multiple asynchronous operations

    - by kimsia
    Note: This question is also cross-posted in Q.js mailing list over here. i had a situation with multiple asynchronous operations and the answer I accepted pointed out that using Promises using a library such as q.js would be more beneficial. I am convinced to refactor my code to use Promises but because the code is pretty long, i have trimmed the irrelevant portions and exported the crucial parts into a separate repo. The repo is here and the most important file is this. The requirement is that I want pageSizes to be non-empty after traversing all the dragged'n dropped files. The problem is that the FileAPI operations inside getSizeSettingsFromPage function causes getSizeSettingsFromPage to be async. So I cannot place checkWhenReady(); like this. function traverseFiles() { for (var i=0, l=pages.length; i<l; i++) { getSizeSettingsFromPage(pages[i], calculateRatio); } checkWhenReady(); // this always returns 0. } This works, but it is not ideal. I prefer to call checkWhenReady just ONCE after all the pages have undergone this function calculateRatio successfully. function calculateRatio(width, height, filename) { // .... code pageSizes.add(filename, object); checkWhenReady(); // this works but it is not ideal. I prefer to call this method AFTER all the `pages` have undergone calculateRatio // ..... more code... } How do I refactor the code to make use of Promises in Q.js?

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  • java threads don't see shared boolean changes

    - by andymur
    Here the code class Aux implements Runnable { private Boolean isOn = false; private String statusMessage; private final Object lock; public Aux(String message, Object lock) { this.lock = lock; this.statusMessage = message; } @Override public void run() { for (;;) { synchronized (lock) { if (isOn && "left".equals(this.statusMessage)) { isOn = false; System.out.println(statusMessage); } else if (!isOn && "right".equals(this.statusMessage)) { isOn = true; System.out.println(statusMessage); } if ("left".equals(this.statusMessage)) { System.out.println("left " + isOn); } } } } } public class Question { public static void main(String [] args) { Object lock = new Object(); new Thread(new Aux("left", lock)).start(); new Thread(new Aux("right", lock)).start(); } } In this code I expect to see: left, right, left right and so on, but when Thread with "left" message changes isOn to false, Thread with "right" message don't see it and I get ("right true" and "left false" console messages), left thread don't get isOn in true, but right Thread can't change it cause it always see old isOn value (true). When i add volatile modifier to isOn nothing changes, but if I change isOn to some class with boolean field and change this field then threads are see changes and it works fine Thanks in advance.

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  • Can Microsoft store three-valued fields in a single bit?

    - by fenomas
    I'm completely ignorant of SQL/databases, but I was chatting with a friend who does a lot of database work about how some databases use a "boolean" field that can take a value of NULL in addition to true and false. Regarding this, he made a comment along these lines: "To Microsoft's credit, they have never referred to that kind of field as a boolean, they just call it a bit. And it's a true bit - if you have eight or fewer bit fields in a record, it only requires one byte to store them all." Naturally that seems impossible to me - if the field can hold three values you're not going to fit eight of them into a byte. My friend agreed that it seemed odd, but begged ignorance of the low-level internals and said that so far as he knew, such fields can hold three values when viewed from the SQL side, and it does work out to require a byte of storage. I imagine one of us has a wire crossed. Can anyone explain what's really going on here?

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  • Deleting the first occurrence of a target in aList [closed]

    - by Bandz Jooz
    /** Replaces each occurrence of oldItem in aList with newItem */ public static void replace(List<Student> aList, Student oldItemStudent newItem) { int index = aList.indexOf(oldItem); while(index != -1){ aList.set(index, newItem); index = aList.indexOf(oldItem); } /** Deletes the first occurrence of target in aList */ public static void delete(List<Student> aList, Student target){ Object o = //stuck here, dont know how to set up boolean stuff } } I figured out how to do the first method by looking up Java documentation, however I can't figure out how to finish my code for the second method even though I looked up the documentation which states: boolean remove(Object o) Removes the first occurrence of the specified element from this list, if it is present.

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  • Distributed Computing Framework (.NET) - Specifically for CPU Instensive operations

    - by StevenH
    I am currently researching the options that are available (both Open Source and Commercial) for developing a distributed application. "A distributed system consists of multiple autonomous computers that communicate through a computer network." Wikipedia The application is focused on distributing highly cpu intensive operations (as opposed to data intensive) so I'm sure MapReduce solutions don't fit the bill. Any framework that you can recommend ( + give a brief summary of any experience or comparison to other frameworks ) would be greatly appreciated. Thanks.

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