Search Results

Search found 2221 results on 89 pages for 'equal'.

Page 79/89 | < Previous Page | 75 76 77 78 79 80 81 82 83 84 85 86  | Next Page >

• Deduping your redundancies

  - by nospam(at)example.com (Joerg Moellenkamp)

  Robin Harris of Storagemojo pointed to an interesting article about about deduplication and it's impact to the resiliency of your data against data corruption on ACM Queue. The problem in short: A considerable number of filesystems store important metadata at multiple locations. For example the ZFS rootblock is copied to three locations. Other filesystems have similar provisions to protect their metadata. However you can easily proof, that the rootblock pointer in the uberblock of ZFS for example is pointing to blocks with absolutely equal content in all three locatition (with zdb -uu and zdb -r). It has to be that way, because they are protected by the same checksum. A number of devices offer block level dedup, either as an option or as part of their inner workings. However when you store three identical blocks on them and the devices does block level dedup internally, the device may just deduplicated your redundant metadata to a block stored just once that is stored on the non-voilatile storage. When this block is corrupted, you have essentially three corrupted copies. Three hit with one bullet. This is indeed an interesting problem: A device doing deduplication doesn't know if a block is important or just a datablock. This is the reason why I like deduplication like it's done in ZFS. It's an integrated part and so important parts don't get deduplicated away. A disk accessed by a block level interface doesn't know anything about the importance of a block. A metadata block is nothing different to it's inner mechanism than a normal data block because there is no way to tell that this is important and that those redundancies aren't allowed to fall prey to some clever deduplication mechanism. Robin talks about this in regard of the Sandforce disk controllers who use a kind of dedup to reduce some of the nasty effects of writing data to flash, but the problem is much broader. However this is relevant whenever you are using a device with block level deduplication. It's just the point that you have to activate it for most implementation by command, whereas certain devices do this by default or by design and you don't know about it. However I'm not perfectly sure about that ? given that storage administration and server administration are often different groups with different business objectives I would ask your storage guys if they have activated dedup without telling somebody elase on their boxes in order to speak less often with the storage sales rep. The problem is even more interesting with ZFS. You may use ditto blocks to protect important data to store multiple copies of data in the pool to increase redundancy, even when your pool just consists out of one disk or just a striped set of disk. However when your device is doing dedup internally it may remove your redundancy before it hits the nonvolatile storage. You've won nothing. Just spend your disk quota on the the LUNs in the SAN and you make your disk admin happy because of the good dedup ratio However you can just fall in this specific "deduped ditto block"trap when your pool just consists out of a single device, because ZFS writes ditto blocks on different disks, when there is more than just one disk. Yet another reason why you should spend some extra-thought when putting your zpool on a single LUN, especially when the LUN is sliced and dices out of a large heap of storage devices by a storage controller. However I have one problem with the articles and their specific mention of ZFS: You can just hit by this problem when you are using the deduplicating device for the pool. However in the specifically mentioned case of SSD this isn't the usecase. Most implementations of SSD in conjunction with ZFS are hybrid storage pools and so rotating rust disk is used as pool and SSD are used as L2ARC/sZIL. And there it simply doesn't matter: When you really have to resort to the sZIL (your system went down, it doesn't matter of one block or several blocks are corrupt, you have to fail back to the last known good transaction group the device. On the other side, when a block in L2ARC is corrupt, you simply read it from the pool and in HSP implementations this is the already mentioned rust. In conjunction with ZFS this is more interesting when using a storage array, that is capable to do dedup and where you use LUNs for your pool. However as mentioned before, on those devices it's a user made decision to do so, and so it's less probable that you deduplicating your redundancies. Other filesystems lacking acapability similar to hybrid storage pools are more "haunted" by this problem of SSD using dedup-like mechanisms internally, because those filesystem really store the data on the the SSD instead of using it just as accelerating devices. However at the end Robin is correct: It's jet another point why protecting your data by creating redundancies by dispersing it several disks (by mirror or parity RAIDs) is really important. No dedup mechanism inside a device can dedup away your redundancy when you write it to a totally different and indepenent device.

  Read the article

• Determining the angle to fire a shot when target and shooter moves, and bullet moves with shooter velocity added in

  - by Azaral

  I saw this question: Predicting enemy position in order to have an object lead its target and followed the link in the answer to stack overflow. In the stack overflow page I used the 2nd answer, the one that is a large mathematical derivation. My situation is a little different though. My first question though is will the answer provided in the stack overflow page even work to begin with, assuming the original circumstances of moving target and stationary shooter. My situation is a little different than that situation. My target moves, the shooter moves, and the bullets from the shooter start off with the velocities in x and y added to the bullets' x and y velocities. If you are sliding to the right, the bullets will remain in front of you as you move so as long as your velocity remains constant. What I'm trying to do is to get the enemy to be able to determine where they need to shoot in order to hit the player. Unless the player and enemy is stationary, the velocity from the ship adding to the velocity of the bullets will cause a miss. I'd rather like to prevent that. I used the formula in the stack overflow answer and did what I thought were the appropriate adjustments. I've been banging at this for the last four hours and I just can't make it click. It is probably something really simple and boneheaded that I am missing (that seems to be a lot of my problems lately). Here is the solution presented from the stack overflow answer: It boils down to solving a quadratic equation of the form: a * sqr(x) + b * x + c == 0 Note that by sqr I mean square, as opposed to square root. Use the following values: a := sqr(target.velocityX) + sqr(target.velocityY) - sqr(projectile_speed) b := 2 * (target.velocityX * (target.startX - cannon.X) + target.velocityY * (target.startY - cannon.Y)) c := sqr(target.startX - cannon.X) + sqr(target.startY - cannon.Y) Now we can look at the discriminant to determine if we have a possible solution. disc := sqr(b) - 4 * a * c If the discriminant is less than 0, forget about hitting your target -- your projectile can never get there in time. Otherwise, look at two candidate solutions: t1 := (-b + sqrt(disc)) / (2 * a) t2 := (-b - sqrt(disc)) / (2 * a) Note that if disc == 0 then t1 and t2 are equal. If there are no other considerations such as intervening obstacles, simply choose the smaller positive value. (Negative t values would require firing backward in time to use!) Substitute the chosen t value back into the target's position equations to get the coordinates of the leading point you should be aiming at: aim.X := t * target.velocityX + target.startX aim.Y := t * target.velocityY + target.startY Here is my code, after being corrected by Sam Hocevar (thank you again for your help!). It still doesn't work. For some reason it never enters the section of code inside the if(disc = 0) (obviously because it is always less than zero but...). However, if I plug the numbers from my game log on the enemy and player positions and velocities it outputs a valid firing solution. I have looked at the code side by side a couple of times now and I can't find any differences. There has got to be something simple I'm missing here. If someone else could look at this code and determine what is going on here I'd appreciate it. I know it's not going through that section because if it were, shouldShoot would become true and the enemy would be blasting away at the player. This section calls the function in question, CalculateShootHeading() if(shouldMove) { UseEngines(); } x += xVelocity; y += yVelocity; CalculateShootHeading(); if(shouldShoot) { ShootWeapons(); } UpdateWeapons(); This is CalculateShootHeading(). This is inside the enemy class so x and y are the enemy's x and y and the same with velocity. One output from my game log gives Player X = 2108, Player Y = -180.956, Player X velocity = 10.9949, Player Y Velocity = -6.26017, Enemy X = 1988.31, Enemy Y = -339.051, Enemy X velocity = 1.81666, Enemy Y velocity = -9.67762, 0 enemy projectiles. The output from the console tester is Bullet position = 2210.49, -239.313 and Player Position = 2210.49, -239.313. This doesn't make any sense. The only thing that could be different is the code or the input into my function in the game and I've checked that and I don't think that it is wrong as it's updated before this and never changed. float const bulletSpeed = 30.f; float const dx = playerX - x; float const dy = playerY - y; float const vx = playerXVelocity - xVelocity; float const vy = playerYVelocity - yVelocity; float const a = vx * vx + vy * vy - bulletSpeed * bulletSpeed; float const b = 2.f * (vx * dx + vy * dy); float const c = dx * dx + dy * dy; float const disc = b * b - 4.f * a * c; shouldShoot = false; if (disc >= 0.f) { float t0 = (-b - std::sqrt(disc)) / (2.f * a); float t1 = (-b + std::sqrt(disc)) / (2.f * a); if (t0 < 0.f || (t1 < t0 && t1 >= 0.f)) { t0 = t1; } if (t0 >= 0.f) { float shootx = vx + dx / t0; float shooty = vy + dy / t0; heading = std::atan2(shooty, shootx) * RAD2DEGREE; } shouldShoot = true; }

  Read the article

• [C#] Convert string to double with 2 digit after decimal separator

  - by st.stoqnov

  All began with these simple lines of code: string s = "16.9"; double d = Convert.ToDouble(s); d*=100; The result should be 1690.0, but it's not. d is equal to 1689.9999999999998. All I want to do is to round a double to value with 2 digit after decimal separator. Here is my function. private double RoundFloat(double Value) { float sign = (Value < 0) ? -0.01f : 0.01f; if (Math.Abs(Value) < 0.00001) Value = 0; string SVal = Value.ToString(); string DecimalSeparator = System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator; int i = SVal.IndexOf(DecimalSeparator); if (i > 0) { int SRnd; try { // ????? ??????? ????? ???? ?????????? ?????????? SRnd = Convert.ToInt32(SVal.Substring(i + 3, 1)); } catch { SRnd = 0; } if (SVal.Length > i + 3) SVal = SVal.Substring(0, i + 3); //SVal += "00001"; try { double result = (SRnd >= 5) ? Convert.ToDouble(SVal) + sign : Convert.ToDouble(SVal); //result = Math.Round(result, 2); return result; } catch { return 0; } } else { return Value; } But again the same problem, converting from string to double is not working as I want. A workaround to this problem is to concatenate "00001" to the string and then use the Math.Round function (commented in the example above). This double value multiplied to 100 (as integer) is send to a device (cash register) and this values must be correct. I am using VS2005 + .NET CF 2.0 Is there another more "elegant" solution, I am not happy with this one.

  Read the article

• Runge-Kutta (RK4) integration for game physics

  - by Kai

  Gaffer on Games has a great article about using RK4 integration for better game physics. The implementation is straightforward but the math behind it confuses me. I understand derivatives and integrals on a conceptual level but I haven't manipulated equations in a long time. Here's the brunt of Gaffer's implementation: void integrate(State &state, float t, float dt) { Derivative a = evaluate(state, t, 0.0f, Derivative()); Derivative b = evaluate(state, t+dt*0.5f, dt*0.5f, a); Derivative c = evaluate(state, t+dt*0.5f, dt*0.5f, b); Derivative d = evaluate(state, t+dt, dt, c); const float dxdt = 1.0f/6.0f * (a.dx + 2.0f*(b.dx + c.dx) + d.dx); const float dvdt = 1.0f/6.0f * (a.dv + 2.0f*(b.dv + c.dv) + d.dv) state.x = state.x + dxdt * dt; state.v = state.v + dvdt * dt; } Can anybody explain in simple terms how RK4 works? Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? After reading the accepted answer below, and several other articles, I have a grasp on how RK4 works. To answer my own questions: Can anybody explain in simple terms how RK4 works? RK4 takes advantage of the fact that we can get a much better approximation of a function if we use its higher-order derivatives rather than just the first or second derivative. That's why the Taylor series converges much faster than Euler approximations. (take a look at the animation on the right side of that page) Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? The Runge-Kutta method is an approximation of a function that samples derivatives of several points within a timestep, unlike the Taylor series which only samples derivatives of a single point. After sampling these derivatives we need to know how to weigh each sample to get the closest approximation possible. An easy way to do this is to pick constants that coincide with the Taylor series, which is how the constants of a Runge-Kutta equation are determined. This article made it clearer for me: http://web.mit.edu/10.001/Web/Course%5FNotes/Differential%5FEquations%5FNotes/node5.html. Notice how (15) is the Taylor series expansion while (17) is the Runge-Kutta derivation. How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? Mathematically it converges much faster than doing many Euler approximations. Of course, with enough Euler approximations we can gain equal accuracy to RK4, but the computational power needed doesn't justify using Euler.

  Read the article

• Comparing strings with user-created string class

  - by meepz

  Basically, I created my own string class, mystring.h and mystring.c. What I want to do is write a function that compares two "strings" and then returns 1 first word is larger than the second, the opposite if word 2 is larger than word 1, and 0 if the two words are equal. What I have so far is this: int compareto(void * S1, void * S2){ String s1 = (String S1); String s2 = (String S2); int i, cs1 = 0, cs2 = 0; //cs1 is count of s1, cs2 is count of s2 while(s1->c[i] != '\0'){ //basically, while there is a word if(s1->c[i] < s2->c[i]) // if string 1 char is less than string 2 char cs2++; //add to string 2 count else (s1->c[i] > s2->c[i]) //vice versa cs1++; i++; } for my return I basically have if(cs1>cs2){ return 1; } else if(cs2 > cs1){ return 2; } return 0; here is mystring.h typedef struct mystring { char * c; int length; int (*sLength)(void * s); char (*charAt)(void * s, int i); int (*compareTo)(void * s1, void * s2); struct mystring * (*concat)(void * s1, void * s2); struct mystring * (*subString)(void * s, int begin, int end); void (*printS)(void * s); } string_t; typedef string_t * String; This does what I want, but only for unspecified order. What I want to do is search through my linked list for the last name. Ex. I have two entries in my linked list, smith and jones; Jones will be output as greater than smith, but alphabetically it isnt. (I'm using this to remove student entries from a generic link list I created) Any suggestions, all of my google searches involve using the library, so I've had no luck)

  Read the article

• Delete Nodes + attributes that match Xpath except specific attributes

  - by Ryan Ternier

  I'm trying to find the best (efficient) way of doing this. I have a medium sized XML document. Depending on specific settings certain portions of it need to be filtered out for security reasons. I'll be doing this in XSLT as it's configurable and no code should need changing. I've looked around, but not getting much luck on it. For example: I have the following XPath: //*[@root='2.16.840.1.113883.3.51.1.1.6.1'] Whicrooth gives me all nodes with a root attribute equal to a specific OID. In these nodes I want to have all attributes except for a few (ex. foo and bar) erased, and then having another attribute added (ex. reason) I also need to have multiple XPath expressions that can be ran to zero down on a specific node and clear it's contents out in a similar fashion, with respect to nodes with specific attributes. I'm playing around with information from: XPath expression to select all XML child nodes except a specific list? and XSLT Remove Elements and/or Attributes by Name per XSL Parameters Will update shortly when I can have access what what I"ve done so far. Example: XML Before Transformation <root> <childNode> <innerChild root="2.16.840.1.113883.3.51.1.1.6.1" a="b" b="c" type="innerChildness"/> <innerChildSibling/> </childNode> <animals> <cat> <name>bob</name> </cat> </animals> <tree/> <water root="2.16.840.1.113883.3.51.1.1.6.1" z="zed" l="ell" type="liquidLIke"/> </root> After <root> <childNode> <innerChild root="2.16.840.1.113883.3.51.1.1.6.1" flavor="MSK"/> <!-- filtered --> <innerChildSibling/> </childNode> <animals> <cat flavor="MSK" /> <!-- cat was filtered --> </animals> <tree/> <water root="2.16.840.1.113883.3.51.1.1.6.1" flavor="MSK"/> <!-- filtered --> </root>

  Read the article

• SIFR 3.0 - Font Size

  - by Nick

  I have been working with SIFR 3.0 for some time now and the font-size never seems to work correctly. I understand the most basic concepts behind SIFR. SIFR runs when you load the page. It does some calculations one the size of the HTML rendered font and then replaces it with a flash movie that is roughly equal to that size. Because of this, you want to style your HTML font to match the size of your SIFR font as close as possible. My problem always comes up when trying to style these two font sizes to match. Let's say I want to use a SIFR font of Helvetica Neue Lt at about 32px. The HTML equivalent is something like Arial Narrow at about 36px with some negative letter spacing. So here is what I do. In sifr.css I'll write: @media screen { .sIFR-active h1 { visibility: hidden; z-index: 0 !important; font-size: 36px; } } Great, that gets the default HTML font the size I need. Now I need to update the flash SIFR font size. So I go into sifr-config.js and write something like this: sIFR.replace(HelveticaNeueThinCond, { selector: 'h1', css: '.sIFR-root { color: #762123; font-size: 32px; line-height: 1em; }', transparent: true }); So right now everything is working great. That is until my h1 text wraps more than one line. For some reason, when the text wraps it only shows the first line. It seems calculates the height wrong. This is very weird because I ran some tests. I took "visibility: hidden" off of "sIFR-active h1" to make sure that the HTML rendered text was the right size. It is, it takes up two lines. However, when the Flash replaces this text it gives it a min-height of one line of text. Odd. The only way I could find to fix this wrapping problem was to remove "font-size: 32px;" from "sIFR.replace(HelveticaNeueThinCond" in sifr-config. The problem I run into then is that it inherits the font-size set in sifr.css. Now the problem is that my HTML text is bigger then the SIFR text. So occasional my HTML text will wrap to a new line before my SIFR text leaving a big white space. So, how do I set two different font-size (one for my HTML text and one for my SIFR) without losing the wrapping. The only time I have been able to use the successfully is when I have a SIFR font that is so similar to a web safe font that they can share the same font-size attribute. Thanks

  Read the article

• jQueryUI autocomplete - when no results are returned

  - by Brian M. Hunt

  I'm wondering how one can catch and add a custom handler when empty results are returned from the server when using jQueryUI autocomplete. There seem to be a few questions on this point related to the various jQuery plugins (e.g. jQuery autocomplete display “No data” error message when results empty), but I am wondering if there's a better/simpler way to achieve the same with the jQueryUI autocomplete. It seems to me this is a common use case, and I thought perhaps that jQueryUI had improved on the jQuery autocomplete by adding the ability to cleanly handle this situation. However I've not been able to find documentation of such functionality, and before I hack away at it I'd like to throw out some feelers in case others have seen this before. While probably not particularly influential, I can have the server return anything - e.g. HTTP 204: No Content to a 200/JSON empty list - whatever makes it easiest to catch the result in jQueryUI's autocomplete. My first thought is to pass a callback with two arguments, namely a request object and a response callback to handle the code, per the documentation: The third variation, the callback, provides the most flexibility, and can be used to connect any data source to Autocomplete. The callback gets two arguments: A request object, with a single property called "term", which refers to the value currently in the text input. For example, when the user entered "new yo" in a city field, the Autocomplete term will equal "new yo". A response callback, which expects a single argument to contain the data to suggest to the user. This data should be filtered based on the provided term, and can be in any of the formats described above for simple local data (String-Array or Object-Array with label/value/both properties). When the response callback receives no data, it inserts returns a special one-line object-array that has a label and an indicator that there's no data (so the select/focus recognize it as the indicator that no-data was returned). This seems overcomplicated. I'd prefer to be able to use a source: "http://...", and just have a callback somewhere indicating that no data was returned. Thank you for reading. Brian

  Read the article

• Color Theory: How to convert Munsell HVC to RGB/HSB/HSL

  - by Ian Boyd

  I'm looking at at document that describes the standard colors used in dentistry to describe the color of a tooth. They quote hue, value, chroma values, and indicate they are from the 1905 Munsell description of color: The system of colour notation developed by A. H. Munsell in 1905 identifies colour in terms of three attributes: HUE, VALUE (Brightness) and CHROMA (saturation) [15] HUE (H): Munsell defined hue as the quality by which we distinguish one colour from another. He selected five principle colours: red, yellow, green, blue, and purple; and five intermediate colours: yellow-red, green-yellow, blue-green, purple-blue, and red-purple. These were placed around a colour circle at equal points and the colours in between these points are a mixture of the two, in favour of the nearer point/colour (see Fig 1.). VALUE (V): This notation indicates the lightness or darkness of a colour in relation to a neutral grey scale, which extends from absolute black (value symbol 0) to absolute white (value symbol 10). This is essentially how ‘bright’ the colour is. CHROMA (C): This indicates the degree of divergence of a given hue from a neutral grey of the same value. The scale of chroma extends from 0 for a neutral grey to 10, 12, 14 or farther, depending upon the strength (saturation) of the sample to be evaluated. There are various systems for categorising colour, the Vita system is most commonly used in Dentistry. This uses the letters A, B, C and D to notate the hue (colour) of the tooth. The chroma and value are both indicated by a value from 1 to 4. A1 being lighter than A4, but A4 being more saturated than A1. If placed in order of value, i.e. brightness, the order from brightest to darkest would be: A1, B1, B2, A2, A3, D2, C1, B3, D3, D4, A3.5, B4, C2, A4, C3, C4 The exact values of Hue, Value and Chroma for each of the shades is shown below (16) So my question is, can anyone convert Munsell HVC into RGB, HSB or HSL? Hue Value (Brightness) Chroma(Saturation) === ================== ================== 4.5 7.80 1.7 2.4 7.45 2.6 1.3 7.40 2.9 1.6 7.05 3.2 1.6 6.70 3.1 5.1 7.75 1.6 4.3 7.50 2.2 2.3 7.25 3.2 2.4 7.00 3.2 4.3 7.30 1.6 2.8 6.90 2.3 2.6 6.70 2.3 1.6 6.30 2.9 3.0 7.35 1.8 1.8 7.10 2.3 3.7 7.05 2.4 They say that Value(Brightness) varies from 0..10, which is fine. So i take 7.05 to mean 70.5%. But what is Hue measured in? i'm used to hue being measured in degrees (0..360). But the values i see would all be red - when they should be more yellow, or brown. Finally, it says that Choma/Saturation can range from 0..10 ...or even higher - which makes it sound like an arbitrary scale. So can anyone convert Munsell HVC to HSB or HSL, or better yet, RGB?

  Read the article

• Haskell newbie on types

  - by garulfo

  I'm completely new to Haskell (and more generally to functional programming), so forgive me if this is really basic stuff. To get more than a taste, I try to implement in Haskell some algorithmic stuff I'm working on. I have a simple module Interval that implements intervals on the line. It contains the type data Interval t = Interval t t the helper function makeInterval :: (Ord t) => t -> t -> Interval t makeInterval l r | l <= r = Interval l r | otherwise = error "bad interval" and some utility functions about intervals. Here, my interest lies in multidimensional intervals (d-intervals), those objects that are composed of d intervals. I want to separately consider d-intervals that are the union of d disjoint intervals on the line (multiple interval) from those that are the union of d interval on d separate lines (track interval). With distinct algorithmic treatments in mind, I think it would be nice to have two distinct types (even if both are lists of intervals here) such as import qualified Interval as I -- Multilple interval newtype MInterval t = MInterval [I.Interval t] -- Track interval newtype TInterval t = TInterval [I.Interval t] to allow for distinct sanity checks, e.g. makeMInterval :: (Ord t) => [I.Interval t] -> MInterval t makeMInterval is = if foldr (&&) True [I.precedes i i' | (i, i') <- zip is (tail is)] then (MInterval is) else error "bad multiple interval" makeTInterval :: (Ord t) => [I.Interval t] -> TInterval t makeTInterval = TInterval I now get to the point, at last! But some functions are naturally concerned with both multiple intervals and track intervals. For example, a function order would return the number of intervals in a multiple interval or a track interval. What can I do? Adding -- Dimensional interval data DInterval t = MIntervalStuff (MInterval t) | TIntervalStuff (TInterval t) does not help much, since, if I understand well (correct me if I'm wrong), I would have to write order :: DInterval t -> Int order (MIntervalStuff (MInterval is)) = length is order (TIntervalStuff (TInterval is)) = length is and call order as order (MIntervalStuff is) or order (TIntervalStuff is) when is is a MInterval or a TInterval. Not that great, it looks odd. Neither I want to duplicate the function (I have many functions that are concerned with both multiple and track intevals, and some other d-interval definitions such as equal length multiple and track intervals). I'm left with the feeling that I'm completely wrong and have missed some important point about types in Haskell (and/or can't forget enough here about OO programming). So, quite a newbie question, what would be the best way in Haskell to deal with such a situation? Do I have to forget about introducing MInterval and TInterval and go with one type only? Thanks a lot for your help, Garulfo

  Read the article

• I getting exception, while deleting a row using " commitEditingStyle " method in iPhone simulator.

  - by Madan Mohan

  Hi, I am getting exception by deleting a row from the table view. (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { if(isEdit == YES) { if([editObject.contactList count]0) { return [editObject.contactList count]+1; } else { return 1; } } else if(isEdit == NO) { if([addContactList count]0) { return [addContactList count]+1; } else { return 1; } } return 0; } (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 1; } -(UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath { if(isEdit == YES) { int sectionNum=[editObject.contactList count]-1; if([editObject.contactList count]0) { for( int i=0; i<=[editObject.contactList count]-1;i++) { if(indexPath.section == i) { return UITableViewCellEditingStyleDelete; } } if(indexPath.section == sectionNum+1) { return UITableViewCellEditingStyleInsert; } } else { if(indexPath.section == 0) { return UITableViewCellEditingStyleInsert; } } } else { if([addContactList count]0) { int sectionNum=[addContactList count]-1; for( int i=0; i<=[addContactList count]-1;i++) { if(indexPath.section == i) { return UITableViewCellEditingStyleDelete; } } if(indexPath.section == sectionNum+1) { return UITableViewCellEditingStyleInsert; } } else { if(indexPath.section == 0) { return UITableViewCellEditingStyleInsert; } } } return UITableViewCellEditingStyleNone; } (void)tableView:(UITableView *)tv commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if(isEdit == YES) { if(editingStyle == UITableViewCellEditingStyleDelete) { for(int i=0;i<=[editObject.contactList count]-1;i++) { if(indexPath.section == i) { [editObject.contactList removeObjectAtIndex:indexPath.row]; [theTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; } } } else { //adding } [theTableView reloadData]; } else { if(editingStyle == UITableViewCellEditingStyleDelete) { for(int i=0;i<=[addContactList count]-1;i++) { if(indexPath.section == i) { [addContactList removeObjectAtIndex:indexPath.row]; [theTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; // getting exception here in this line at indexpath [theTableView reloadData]; } } } else { //adding } [theTableView reloadData]; } } the exception as 2010-04-28 13:55:30.063 Zoho[2818:20b] * Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-984.38/UITableView.m:772 2010-04-28 13:55:30.064 Zoho[2818:20b] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of sections. The number of sections contained in the table view after the update (2) must be equal to the number of sections contained in the table view before the update (3), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted).' 2010-04-28 13:55:30.065 Zoho[2818:20b] Stack: ( 10490971, 2437656123, 10574907

  Read the article

• AutoScaleMode problems with changed default font

  - by Doc Brown

  Hi, I have some problems with the Form.AutoScaleMode property together with fixed size controls, when using a non-default font. I boiled it down to a simple test application (WinForms 2.0) with only one form, some fixed size controls and the following properties: class Form1 : Form { // ... private void InitializeComponent() { // ... this.AutoScaleDimensions = new System.Drawing.SizeF(96F, 96F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Dpi; this.Font = new System.Drawing.Font("Tahoma", 9.25F); // ... } } Under 96dpi, Windows XP, the form looks correctly like this 96 dpi example. Under 120 dpi, Windows XP, the the Windows Forms autoscaling feature produces this 120 dpi example. As you can see, groupboxes, buttons, list or tree views are scaled correctly, multiline text boxes get too big in the vertical axis, and a fixed size label does not scale correctly in both vertical and horizontal direction. Seems to be bug in the .NET framework? Using the default font (Microsoft Sans Serif 8.25pt), this problem does not occur. Using AutoScaleMode=Font (with adequate AutoScaleDimensions, of course) either does not scale at all or scales exactly like seen above, depending on when the Font is set (before or after the change of AutoScaleMode). The problem is not specific to the "Tahoma" Font, it occurs also with Microsoft Sans Serif, 9.25pt. And yes, i already read this SO post http://stackoverflow.com/questions/2114857/high-dpi-problems but it does not really help me. Any suggestions how to come around this? EDIT: I changed my image hoster, hope this one works better. EDIT2: Some additional information about my intention: I have about 50 already working fixed size dialogs with several hundreds of properly placed, fixed size controls. They were migrated from an older C++ GUI framework to C#/Winforms, that's why they are all fixed-size. All of them look fine with 96 dpi using a 9.25pt font. Under the old framework, scaling to 120 dpi worked fine - all fixed size controls scaled equal in both dimensions. Last week, we detected this strange scaling behaviour under WinForms when switching to 120 dpi. You can imagine that most of our dialogs now look very bad under 120 dpi. We are looking for a solution that avoids a complete redesign all those dialogs.

  Read the article

• Updating / refreshing a live geojson layer | JSON & JS Variable

  - by Ozaki

  TLDR I am trying to get my geoJSON layer to update, currently it will 1. Create the vector mark, 2. Remove the vector mark, 3. Set the JS variable for lat and lon, 4. Unset the variable??? :S Hey S O. I have a geojson layer set up as follows: //GeoJSON Layer// var layer1 = new OpenLayers.Layer.GML("My GeoJSON Layer", "coordinates", {format: OpenLayers.Format.GeoJSON, styleMap: style_red}); My features are set up as follows: var latitude = 0.0; // as 0.0 it will draw the point in. var longitude = 0.0; // as 0.0 it will draw the point in. //var longitude = getlongitude; where getlongitude = JSON string of longitude. var point = new OpenLayers.Geometry.Point(longitude, latitude); pointFeature = new OpenLayers.Feature.Vector(point, null, style_red); var style_red = OpenLayers.Util.extend({}, layer_style); style_red.strokeColor = "red"; style_red.fillColor = "black"; style_red.fillOpacity = 0.5; style_red.graphicName = "circle"; style_red.pointRadius = 3.8; style_red.strokeWidth = 2; style_red.strokeLinecap = "butt"; and my layer updating function: function UpdateLayer(){ var p = new OpenLayers.Format.GeoJSON({ 'internalProjection': new OpenLayers.Projection("EPSG:900913"), 'externalProjection': new OpenLayers.Projection("EPSG:4326") }); var url = "coordinates"; OpenLayers.loadURL(url, {}, null, function(r) { var f = p.read(r.responseText); map.layers[2].destroyFeatures(); map.layers[2].addFeatures(pointFeature); }); setTimeout("UpdateLayer()",1000) } Any idea what I am doing wrong or what I am missing? Edit1 It now removes the feature (was map.layers[1]) previously... But will not add the new feature.. Edit2 I managed to get it to redraw a point but not with live data. It should draw the point at what (latitude) & (longitude) are equal to. I am trying to set latitude & longitude to some JSON string but every time straight after it sets the variable it changes it back to "undefined" as soon as it passes the line after var latitude? (using firebug & firequery to debug)

  Read the article

• WPF ComboBox SelectedValue not updating from binding source.

  - by vg1890

  Here's my binding source object: Public Class MyListObject Private _mylist As New ObservableCollection(Of String) Private _selectedName As String Public Sub New(ByVal nameList As List(Of String), ByVal defaultName As String) For Each name In nameList _mylist.Add(name) Next _selectedName = defaultName End Sub Public ReadOnly Property MyList() As ObservableCollection(Of String) Get Return _mylist End Get End Property Public ReadOnly Property SelectedName() As String Get Return _selectedName End Get End Property End Class Here is my XAML: <Window x:Class="Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300" xmlns:local="clr-namespace:WpfApplication1" > <Window.Resources> <ObjectDataProvider x:Key="MyListObject" ObjectInstance="" /> </Window.Resources> <Grid> <ComboBox Height="23" Margin="24,91,53,0" Name="ComboBox1" VerticalAlignment="Top" SelectedValue="{Binding Path=SelectedName, Source={StaticResource MyListObject}, Mode=OneWay}" ItemsSource="{Binding Path=MyList, Source={StaticResource MyListObject}, Mode=OneWay}" /> <Button Height="23" HorizontalAlignment="Left" Margin="47,0,0,87" Name="btn_List1" VerticalAlignment="Bottom" Width="75">List 1</Button> <Button Height="23" Margin="0,0,75,87" Name="btn_List2" VerticalAlignment="Bottom" HorizontalAlignment="Right" Width="75">List 2</Button> </Grid> </Window> Here's the code-behind: Class Window1 Private obj1 As MyListObject Private obj2 As MyListObject Private odp As ObjectDataProvider Public Sub New() InitializeComponent() Dim namelist1 As New List(Of String) namelist1.Add("Joe") namelist1.Add("Steve") obj1 = New MyListObject(namelist1, "Steve") . Dim namelist2 As New List(Of String) namelist2.Add("Bob") namelist2.Add("Tim") obj2 = New MyListObject(namelist2, "Tim") odp = DirectCast(Me.FindResource("MyListObject"), ObjectDataProvider) odp.ObjectInstance = obj1 End Sub Private Sub btn_List1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btn_List1.Click odp.ObjectInstance = obj1 End Sub Private Sub btn_List2_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btn_List2.Click odp.ObjectInstance = obj2 End Sub End Class When the Window first loads, the bindings hook up fine. The ComboBox contains the names "Joe" and "Steve" and "Steve" is selected by default. However, when I click a button to switch the ObjectInstance to obj2, the ComboBox ItemsSource gets populated correctly in the dropdown, but the SelectedValue is set to Nothing instead of being equal to obj2.SelectedName. Thanks in advance!

  Read the article

• How to configure maximum number of transport channels in WCF using basicHttpBinding?

  - by Hemant

  Consider following code which is essentially a WCF host: [ServiceContract (Namespace = "http://www.mightycalc.com")] interface ICalculator { [OperationContract] int Add (int aNum1, int aNum2); } [ServiceBehavior (InstanceContextMode = InstanceContextMode.PerCall)] class Calculator: ICalculator { public int Add (int aNum1, int aNum2) { Thread.Sleep (2000); //Simulate a lengthy operation return aNum1 + aNum2; } } class Program { static void Main (string[] args) { try { using (var serviceHost = new ServiceHost (typeof (Calculator))) { var httpBinding = new BasicHttpBinding (BasicHttpSecurityMode.None); serviceHost.AddServiceEndpoint (typeof (ICalculator), httpBinding, "http://172.16.9.191:2221/calc"); serviceHost.Open (); Console.WriteLine ("Service is running. ENJOY!!!"); Console.WriteLine ("Type 'stop' and hit enter to stop the service."); Console.ReadLine (); if (serviceHost.State == CommunicationState.Opened) serviceHost.Close (); } } catch (Exception e) { Console.WriteLine (e); Console.ReadLine (); } } } Also the WCF client program is: class Program { static int COUNT = 0; static Timer timer = null; static void Main (string[] args) { var threads = new Thread[10]; for (int i = 0; i < threads.Length; i++) { threads[i] = new Thread (Calculate); threads[i].Start (null); } timer = new Timer (o => Console.WriteLine ("Count: {0}", COUNT), null, 1000, 1000); Console.ReadLine (); timer.Dispose (); } static void Calculate (object state) { var c = new CalculatorClient ("BasicHttpBinding_ICalculator"); c.Open (); while (true) { try { var sum = c.Add (2, 3); Interlocked.Increment (ref COUNT); } catch (Exception ex) { Console.WriteLine ("Error on thread {0}: {1}", Thread.CurrentThread.Name, ex.GetType ()); break; } } c.Close (); } } Basically, I am creating 10 proxy clients and then repeatedly calling Add service method. Now if I run both applications and observe opened TCP connections using netstat, I find that: If both client and server are running on same machine, number of tcp connections are equal to number of proxy objects. It means all requests are being served in parallel. Which is good. If I run server on a separate machine, I observed that maximum 2 TCP connections are opened regardless of the number of proxy objects I create. Only 2 requests run in parallel. It hurts the processing speed badly. If I switch to net.tcp binding, everything works fine (a separate TCP connection for each proxy object even if they are running on different machines). I am very confused and unable to make the basicHttpBinding use more TCP connections. I know it is a long question, but please help!

  Read the article

• Help finding longest non-repeating path through connected nodes - Python

  - by Jordan Magnuson

  I've been working on this for a couple of days now without success. Basically, I have a bunch of nodes arranged in a 2D matrix. Every node has four neighbors, except for the nodes on the sides and corners of the matrix, which have 3 and 2 neighbors, respectively. Imagine a bunch of square cards laid out side by side in a rectangular area--the project is actually simulating a sort of card/board game. Each node may or may not be connected to the nodes around it. Each node has a function (get_connections()), that returns the nodes immediately around it that it is connected to (so anywhere from 0 to 4 nodes are returned). Each node also has an "index" property, that contains it's position on the board matrix (eg '1, 4' - row 1, col 4). What I am trying to do is find the longest non-repeating path of connected nodes given a particular "start" node. I've uploaded a couple of images that should give a good idea of what I'm trying to do: In both images, the highlighted red cards are supposedly the longest path of connected cards containing the most upper-left card. However, you can see in both images that a couple of cards that should be in the path have been left out (Romania and Maldova in the first image, Greece and Turkey in the second) Here's the recursive function that I am using currently to find the longest path, given a starting node/card: def get_longest_trip(self, board, processed_connections = list(), processed_countries = list()): #Append this country to the processed countries list, #so we don't re-double over it processed_countries.append(self) possible_trips = dict() if self.get_connections(board): for i, card in enumerate(self.get_connections(board)): if card not in processed_countries: processed_connections.append((self, card)) possible_trips[i] = card.get_longest_trip(board, processed_connections, processed_countries) if possible_trips: longest_trip = [] for i, trip in possible_trips.iteritems(): trip_length = len(trip) if trip_length > len(longest_trip): longest_trip = trip longest_trip.append(self) return longest_trip else: print card_list = [] card_list.append(self) return card_list else: #If no connections from start_card, just return the start card #as the longest trip card_list = [] card_list.append(board.start_card) return card_list The problem here has to do with the processed_countries list: if you look at my first screenshot, you can see that what has happened is that when Ukraine came around, it looked at its two possible choices for longest path (Maldova-Romania, or Turkey, Bulgaria), saw that they were both equal, and chose one indiscriminantly. Now when Hungary comes around, it can't attempt to make a path through Romania (where the longest path would actually be), because Romania has been added to the processed_countries list by Ukraine. Any help on this is EXTREMELY appreciated. If you can find me a solution to this, recursive or not, I'd be happy to donate some $$ to you. I've uploaded my full source code (Python 2.6, Pygame 1.9 required) to: http://www.necessarygames.com/junk/planes_trains.zip The relevant code is in src/main.py, which is all set to run.

  Read the article

• Need help programming with Mclauren series and Taylor series!

  - by user352258

  Ok so here's what i have so far: #include <stdio.h> #include <math.h> //#define PI 3.14159 int factorial(int n){ if(n <= 1) return(1); else return(n * factorial(n-1)); } void McLaurin(float pi){ int factorial(int); float x = 42*pi/180; int i, val=0, sign; for(i=1, sign=-1; i<11; i+=2){ sign *= -1; // alternate sign of cos(0) which is 1 val += (sign*(pow(x, i)) / factorial(i)); } printf("\nMcLaurin of 42 = %d\n", val); } void Taylor(float pi){ int factorial(int); float x; int i; float val=0.00, sign; float a = pi/3; printf("Enter x in degrees:\n"); scanf("%f", &x); x=x*pi/180.0; printf("%f",x); for(i=0, sign=-1.0; i<2; i++){ if(i%2==1) sign *= -1.0; // alternate sign of cos(0) which is 1 printf("%f",sign); if(i%2==1) val += (sign*sin(a)*(pow(x-a, i)) / factorial(i)); else val += (sign*cos(a)*(pow(x-a, i)) / factorial(i)); printf("%d",factorial(i)); } printf("\nTaylor of sin(%g degrees) = %d\n", (x*180.0)/pi, val); } main(){ float pi=3.14159; void McLaurin(float); void Taylor(float); McLaurin(pi); Taylor(pi); } and here's the output: McLaurin of 42 = 0 Enter x in degrees: 42 0.733038-1.00000011.0000001 Taylor of sin(42 degrees) = -1073741824 I suspect the reason for these outrageous numbers goes with the fact that I mixed up my floats and ints? But i just cant figure it out...!! Maybe its a math thing, but its never been a strength of mine let alone program with calculus. Also the Mclaurin fails, how does it equal zero? WTF! Please help correct my noobish code. I am still a beginner...

  Read the article

• Help needed with AES between Java and Objective-C (iPhone)....

  - by Simon Lee

  I am encrypting a string in objective-c and also encrypting the same string in Java using AES and am seeing some strange issues. The first part of the result matches up to a certain point but then it is different, hence when i go to decode the result from Java onto the iPhone it cant decrypt it. I am using a source string of "Now then and what is this nonsense all about. Do you know?" Using a key of "1234567890123456" The objective-c code to encrypt is the following: NOTE: it is a NSData category so assume that the method is called on an NSData object so 'self' contains the byte data to encrypt. - (NSData *)AESEncryptWithKey:(NSString *)key { char keyPtr[kCCKeySizeAES128+1]; // room for terminator (unused) bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding) // fetch key data [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [self length]; //See the doc: For block ciphers, the output size will always be less than or //equal to the input size plus the size of one block. //That's why we need to add the size of one block here size_t bufferSize = dataLength + kCCBlockSizeAES128; void *buffer = malloc(bufferSize); size_t numBytesEncrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES128, NULL /* initialization vector (optional) */, [self bytes], dataLength, /* input */ buffer, bufferSize, /* output */ &numBytesEncrypted); if (cryptStatus == kCCSuccess) { //the returned NSData takes ownership of the buffer and will free it on deallocation return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted]; } free(buffer); //free the buffer; return nil; } And the java encryption code is... public byte[] encryptData(byte[] data, String key) { byte[] encrypted = null; Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); byte[] keyBytes = key.getBytes(); SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES"); try { Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding", "BC"); cipher.init(Cipher.ENCRYPT_MODE, keySpec); encrypted = new byte[cipher.getOutputSize(data.length)]; int ctLength = cipher.update(data, 0, data.length, encrypted, 0); ctLength += cipher.doFinal(encrypted, ctLength); } catch (Exception e) { logger.log(Level.SEVERE, e.getMessage()); } finally { return encrypted; } } The hex output of the objective-c code is - 7a68ea36 8288c73d f7c45d8d 22432577 9693920a 4fae38b2 2e4bdcef 9aeb8afe 69394f3e 1eb62fa7 74da2b5c 8d7b3c89 a295d306 f1f90349 6899ac34 63a6efa0 and the java output is - 7a68ea36 8288c73d f7c45d8d 22432577 e66b32f9 772b6679 d7c0cb69 037b8740 883f8211 748229f4 723984beb 50b5aea1 f17594c9 fad2d05e e0926805 572156d As you can see everything is fine up to - 7a68ea36 8288c73d f7c45d8d 22432577 I am guessing I have some of the settings different but can't work out what, I tried changing between ECB and CBC on the java side and it had no effect. Can anyone help!? please....

  Read the article

• Evaluation of CTEs in SQL Server 2005

  - by Jammer

  I have a question about how MS SQL evaluates functions inside CTEs. A couple of searches didn't turn up any results related to this issue, but I apologize if this is common knowledge and I'm just behind the curve. It wouldn't be the first time :-) This query is a simplified (and obviously less dynamic) version of what I'm actually doing, but it does exhibit the problem I'm experiencing. It looks like this: CREATE TABLE #EmployeePool(EmployeeID int, EmployeeRank int); INSERT INTO #EmployeePool(EmployeeID, EmployeeRank) SELECT 42, 1 UNION ALL SELECT 43, 2; DECLARE @NumEmployees int; SELECT @NumEmployees = COUNT(*) FROM #EmployeePool; WITH RandomizedCustomers AS ( SELECT CAST(c.Criteria AS int) AS CustomerID, dbo.fnUtil_Random(@NumEmployees) AS RandomRank FROM dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') c) SELECT rc.CustomerID, ep.EmployeeID FROM RandomizedCustomers rc JOIN #EmployeePool ep ON ep.EmployeeRank = rc.RandomRank; DROP TABLE #EmployeePool; The following can be assumed about all executions of the above: The result of dbo.fnUtil_Random() is always an int value greater than zero and less than or equal to the argument passed in. Since it's being called above with @NumEmployees which has the value 2, this function always evaluates to 1 or 2. The result of dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') produces a one-column, one-row table that contains a sql_variant with a base type of 'int' that has the value 219935. Given the above assumptions, it makes sense (to me, anyway) that the result of the expression above should always produce a two-column table containing one record - CustomerID and an EmployeeID. The CustomerID should always be the int value 219935, and the EmployeeID should be either 42 or 43. However, this is not always the case. Sometimes I get the expected single record. Other times I get two records (one for each EmployeeID), and still others I get no records. However, if I replace the RandomizedCustomers CTE with a true temp table, the problem vanishes completely. Every time I think I have an explanation for this behavior, it turns out to not make sense or be impossible, so I literally cannot explain why this would happen. Since the problem does not happen when I replace the CTE with a temp table, I can only assume it has something to do with the functions inside CTEs are evaluated during joins to that CTE. Do any of you have any theories?

  Read the article

• Is O_NONBLOCK being set a property of the file descriptor or underlying file?

  - by Daniel Trebbien

  From what I have been reading on The Open Group website on fcntl, open, read, and write, I get the impression that whether O_NONBLOCK is set on a file descriptor, and hence whether non-blocking I/O is used with the descriptor, should be a property of that file descriptor rather than the underlying file. Being a property of the file descriptor means, for example, that if I duplicate a file descriptor or open another descriptor to the same file, then I can use blocking I/O with one and non-blocking I/O with the other. Experimenting with a FIFO, however, it appears that it is not possible to have a blocking I/O descriptor and non-blocking I/O descriptor to the FIFO simultaneously (so whether O_NONBLOCK is set is a property of the underlying file [the FIFO]): #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char **argv) { int fds[2]; if (pipe(fds) == -1) { fprintf(stderr, "`pipe` failed.\n"); return EXIT_FAILURE; } int fd0_dup = dup(fds[0]); if (fd0_dup <= STDERR_FILENO) { fprintf(stderr, "Failed to duplicate the read end\n"); return EXIT_FAILURE; } if (fds[0] == fd0_dup) { fprintf(stderr, "`fds[0]` should not equal `fd0_dup`.\n"); return EXIT_FAILURE; } if ((fcntl(fds[0], F_GETFL) & O_NONBLOCK)) { fprintf(stderr, "`fds[0]` should not have `O_NONBLOCK` set.\n"); return EXIT_FAILURE; } if (fcntl(fd0_dup, F_SETFL, fcntl(fd0_dup, F_GETFL) | O_NONBLOCK) == -1) { fprintf(stderr, "Failed to set `O_NONBLOCK` on `fd0_dup`\n"); return EXIT_FAILURE; } if ((fcntl(fds[0], F_GETFL) & O_NONBLOCK)) { fprintf(stderr, "`fds[0]` should still have `O_NONBLOCK` unset.\n"); return EXIT_FAILURE; // RETURNS HERE } char buf[1]; if (read(fd0_dup, buf, 1) != -1) { fprintf(stderr, "Expected `read` on `fd0_dup` to fail immediately\n"); return EXIT_FAILURE; } else if (errno != EAGAIN) { fprintf(stderr, "Expected `errno` to be `EAGAIN`\n"); return EXIT_FAILURE; } return EXIT_SUCCESS; } This leaves me thinking: is it ever possible to have a non-blocking I/O descriptor and blocking I/O descriptor to the same file and if so, does it depend on the type of file (regular file, FIFO, block special file, character special file, socket, etc.)?

  Read the article

• Zend Framework - Ruby on Rails has a screencast showing how to code a blog in 15 minutes. Does ZF ha

  - by Sootah

  Ruby on Rails has a screencast presentation they use to promote their framework that shows how to code a basic weblog system in 15 minutes with RoR. Does the Zend PHP Framework have a similar screencast/presentation/whatever demonstrating something similar? It doesn't have to be a blog specifically, but I would definitely like to find a presentation that shows some rapid application development using ZF. Where I'm coming from: I have been programming on and off for years now. I started out with QBASIC waaaaay back in the day making little programs (text adventure games, screensavers, simple little things). I then moved to C++ but never really did anything too impressive with it. Since then (probably 5 years or so now) I have started to use C# for my desktop development and PHP for my web development. I've made some pretty cool tools here and there, but am certainly not a professional programmer by any stretch of the term as it has always simply been a hobby of mine. Right now I have two major web applications that I will start work on shortly. (Like tomorrow, or later tonight ideally.. :) ) Both will be database-driven apps that will require user registration, the ability to manipulate data that is specific to their account (their posts, listings, user account details, etc), amongst other things. Currently I am evaluating different frameworks to help me develop these web apps more quickly. I've been looking at, and have heard good things about Ruby on Rails. Hulu and YellowPages.com using it is an obvious endorsement - Of course, I have heard about the scalability issues that it potentially has; but that shouldn't be an issue with what I am working on. I don't expect millions of users per day for either project. I am also seriously looking at the Zend Framework for my needs because I already have some experience with PHP. Ideally I would like to find a ZF screencast that shows an app being written quickly so that I have a roughly equal comparison between the two options I am exploring and can see first-hand how things get done in both. That said - I am not opposed to considering frameworks other than RoR or ZF. The only research I've done on the subject has been over the past couple of days so I am quite certain that there are other excellent options out there that I've not even looked at - or heard of. Of course, it'd be awesome if there is a rapid app dev presentation that I can watch for whatever else is suggested. So - Suggestions? Links to good screencasts that show rapid application development in other frameworks? Are there other PHP frameworks that I should be considering? (Ones that are easy to deploy would be ideal, so I don't have to purchase a dedicated server that I have full control over. I'd like to keep my hosting costs down assuming that it's reasonable) Thanks in advance! -Sootah

  Read the article

• integriting facebook login button with Facebooker (rails plugin)

  - by dexterdeng

  I was integriting login-button with Facebooker, as I wanted to use facepile and customise the facebook login button, so I have to use facebook js sdk. I used the facebooker to connect facebook. now I found a issue. window.fbAsyncInit = function() { FB.init({ appId: '<%=Facebooker.api_key%>', status: true, cookie: true, xfbml: true }); }; (function() { var e = document.createElement('script'); e.type = 'text/javascript'; e.src = document.location.protocol + '//connect.facebook.net/en_US/all.js'; e.async = true; document.getElementById('fb-root').appendChild(e); }()); function fblogin(){ var pearms = "email,user_birthday,friends_location,offline_access,publish_stream,read_friendlists,user_birthday,user_location"; FB.getLoginStatus(function(response) { if (response.session) { // logged in and connected user, someone you know window.location = "http://domain/account/link_user_accounts"; return true; } else { // no user session available, someone you dont know FB.login(function(response) { if (response.session) { if (response.perms) { // after logged in the facebook account. $.inspect(response.perms);//return all these perms I expected. it should be fine there. window.location = "http://domain/account/link_user_accounts"; } return true; } else { return false; } },"email,user_birthday,friends_location,offline_access,publish_stream,read_friendlists"); } }) }; Let's say if the api_key is "1111111111". take a look at this line: " ` if (response.session) { if (response.perms) { $.inspect(response.perms); " now I was trying to login , call fblogin() , I'm sure that the response.perms equal to the perms I expected. (btw, at that time, I have a facebook plugin named facepile works too, it showed my friends after I called fblogin() and connected to facebook by typing my email and password ). so now it should run window.location = "http://domain/account/link_user_accounts"; yes, this line run. but the facebook_session can't build successfully. after digging the facebooker's code, I found this from the rails plugin facebooker: def create_facebook_session secure_with_facebook_params! || secure_with_cookies! || secure_with_token! end mostly, it would run secure_with_cookies! , and if the cookies with keys as "fbs_#{Facebooker.api_key}","#{Facebooker.api_key}_ss", "#{Facebooker.api_key}_session_key",.. created, then the facebook_session can be created. but these cookies can't be created after I logged in facebook until I refresh the current page by hand . I noticed if I refresh the page, the cookies with these keys added to the browser. but why they can't be added after I logged in facebook at once? I need these keys to create facebook_session. did I forgot something excepted these code I pasted? anybody help? thank you very much!

  Read the article

• Delay keyboard input help

  - by Stradigos

  I'm so close! I'm using the XNA Game State Management example found here and trying to modify how it handles input so I can delay the key/create an input buffer. In GameplayScreen.cs I've declared a double called elapsedTime and set it equal to 0. In the HandleInput method I've changed the Key.Right button press to: if (keyboardState.IsKeyDown(Keys.Left)) movement.X -= 50; if (keyboardState.IsKeyDown(Keys.Right)) { elapsedTime -= gameTime.ElapsedGameTime.TotalMilliseconds; if (elapsedTime <= 0) { movement.X += 50; elapsedTime = 10; } } else { elapsedTime = 0; } The pseudo code: If the right arrow key is not pressed set elapsedTime to 0. If it is pressed, the elapsedTime equals itself minus the milliseconds since the last frame. If the difference then equals 0 or less, move the object 50, and then set the elapsedTime to 10 (the delay). If the key is being held down elapsedTime should never be set to 0 via the else. Instead, after elapsedTime is set to 10 after a successful check, the elapsedTime should get lower and lower because it's being subtracted by the TotalMilliseconds. When that reaches 0, it successfully passes the check again and moves the object once more. The problem is, it moves the object once per press but doesn't work if you hold it down. Can anyone offer any sort of tip/example/bit of knowledge towards this? Thanks in advance, it's been driving me nuts. In theory I thought this would for sure work. CLARIFICATION Think of a grid when your thinking about how I want the block to move. Instead of just fluidly moving across the screen, it's moving by it's width (sorta jumping) to the next position. If I hold down the key, it races across the screen. I want to slow this whole process down so that holding the key creates an X millisecond delay between it 'jumping'/moving by it's width. EDIT: Turns out gameTime.ElapsedGameTime.TotalMilliseconds is returning 0... all of the time. I have no idea why.

  Read the article

• For loop from assembly to C

  - by FranXh

  I have a bomb project where I need to defuse certain phases by finding "pas phrases" that will defuse the bomb. Right now I have been working with phase_2, for which the assembly code is shown below. Phase_2 requires as an input 6 numbers, which I need to find in order to defuse this phase. I analyzed this assembly, and I came up with the C code below, that covers lines from 40101c to 401044. It is basically a for loop that makes sure that elements t[0]==t[3], t[1]==t[4] and t[2]==t[5] that the user inputs, are equal. According to my logic, the user can input any 6 numbers as long as the above condition is satisfied. Say 1, 2, 3, 1, 2, 3 would be a valid "pas phrase". However this solution does not convince me for some reason. Am I doing something wrong? 0000000000400ffc <phase_2>: 400ffc: 48 89 5c 24 e0 mov %rbx,-0x20(%rsp) 401001: 48 89 6c 24 e8 mov %rbp,-0x18(%rsp) 401006: 4c 89 64 24 f0 mov %r12,-0x10(%rsp) 40100b: 4c 89 6c 24 f8 mov %r13,-0x8(%rsp) 401010: 48 83 ec 48 sub $0x48,%rsp 401014: 48 89 e6 mov %rsp,%rsi 401017: e8 65 0a 00 00 callq 401a81 <read_six_numbers> 40101c: 48 89 e5 mov %rsp,%rbp 40101f: 4c 8d 6c 24 0c lea 0xc(%rsp),%r13 401024: 41 bc 00 00 00 00 mov $0x0,%r12d 40102a: 48 89 eb mov %rbp,%rbx 40102d: 8b 45 0c mov 0xc(%rbp),%eax 401030: 39 45 00 cmp %eax,0x0(%rbp) 401033: 74 05 je 40103a <phase_2+0x3e> 401035: e8 2d 09 00 00 callq 401967 <_GLOBAL_RESET_> 40103a: 44 03 23 add (%rbx),%r12d 40103d: 48 83 c5 04 add $0x4,%rbp 401041: 4c 39 ed cmp %r13,%rbp 401044: 75 e4 jne 40102a <phase_2+0x2e> 401046: 45 85 e4 test %r12d,%r12d 401049: 75 05 jne 401050 <phase_2+0x54> 40104b: e8 17 09 00 00 callq 401967 <_GLOBAL_RESET_> 401050: 48 8b 5c 24 28 mov 0x28(%rsp),%rbx 401055: 48 8b 6c 24 30 mov 0x30(%rsp),%rbp 40105a: 4c 8b 64 24 38 mov 0x38(%rsp),%r12 40105f: 4c 8b 6c 24 40 mov 0x40(%rsp),%r13 401064: 48 83 c4 48 add $0x48,%rsp 401068: c3 for (int i=0; i<3; i++){ if(t[i] != t[i+3]){ explode(); } }

  Read the article

• Can you find a pattern to sync files knowing only dates and filenames?

  - by Robert MacLean

  Imagine if you will a operating system that had the following methods for files Create File: Creates (writes) a new file to disk. Calling this if a file exists causes a fault. Update File: Updates an existing file. Call this if a file doesn't exist causes a fault. Read File: Reads data from a file. Enumerate files: Gets all files in a folder. Files themselves in this operating system only have the following meta data: Created Time: The original date and time the file was created, by the Create File method. Modified Time: The date and time the file was last modified by the Update File method. If the file has never been modified, this will equal the Create Time. You have been given the task of writing an application which will sync the files between two directories (lets call them bill and ted) on a machine. However it is not that simple, the client has required that The application never faults (see methods above). That while the application is running the users can add and update files and those will be sync'd next time the application runs. Files can be added to either the ted or bill directories. File names cannot be altered. The application will perform one sync per time it is run. The application must be almost entirely in memory, in other words you cannot create a log of filenames and write that to disk and then check that the next time. The exception to point 6 is that you can store date and times between runs. Each date/time is associated with a key labeled A through J (so you have 10 to use) so you can compare keys between runs. There is no way to catch exceptions in the application. Answer will be accepted based on the following conditions: First answer to meet all requirements will be accepted. If there is no way to meet all requirements, the answer which ensures the smallest amount of missed changes per sync will be accepted. A bounty will be created (100 points) as soon as possible for the prize. The winner will be selected one day before the bounty ends. Please ask questions in the comments and I will gladly update and refine the question on those.

  Read the article

< Previous Page | 75 76 77 78 79 80 81 82 83 84 85 86  | Next Page >