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  • Valid JavaScript code that is NOT valid ActionScript 3.0 code?

    - by knorv
    Most JavaScript code is also syntactically valid ActionScript 3.0 code. However, there are exceptions which leads me to my question: Which constructs/features in JavaScript are syntactically invalid in ActionScript 3.0? Please provide concrete examples of JavaScript code (basic JavaScript code without DOM API usage) that is NOT valid ActionScript 3.0 code.

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  • Representing game states in Tic Tac Toe

    - by dacman
    The goal of the assignment that I'm currently working on for my Data Structures class is to create a of Quantum Tic Tac Toe with an AI that plays to win. Currently, I'm having a bit of trouble finding the most efficient way to represent states. Overview of current Structure: AbstractGame Has and manages AbstractPlayers (game.nextPlayer() returns next player by int ID) Has and intializes AbstractBoard at the beginning of the game Has a GameTree (Complete if called in initialization, incomplete otherwise) AbstractBoard Has a State, a Dimension, and a Parent Game Is a mediator between Player and State, (Translates States from collections of rows to a Point representation Is a StateConsumer AbstractPlayer Is a State Producer Has a ConcreteEvaluationStrategy to evaluate the current board StateTransveralPool Precomputes possible transversals of "3-states". Stores them in a HashMap, where the Set contains nextStates for a given "3-state" State Contains 3 Sets -- a Set of X-Moves, O-Moves, and the Board Each Integer in the set is a Row. These Integer values can be used to get the next row-state from the StateTransversalPool SO, the principle is Each row can be represented by the binary numbers 000-111, where 0 implies an open space and 1 implies a closed space. So, for an incomplete TTT board: From the Set<Integer> board perspective: X_X R1 might be: 101 OO_ R2 might be: 110 X_X R3 might be: 101, where 1 is an open space, and 0 is a closed space From the Set<Integer> xMoves perspective: X_X R1 might be: 101 OO_ R2 might be: 000 X_X R3 might be: 101, where 1 is an X and 0 is not From the Set<Integer> oMoves perspective: X_X R1 might be: 000 OO_ R2 might be: 110 X_X R3 might be: 000, where 1 is an O and 0 is not Then we see that x{R1,R2,R3} & o{R1,R2,R3} = board{R1,R2,R3} The problem is quickly generating next states for the GameTree. If I have player Max (x) with board{R1,R2,R3}, then getting the next row-states for R1, R2, and R3 is simple.. Set<Integer> R1nextStates = StateTransversalPool.get(R1); The problem is that I have to combine each one of those states with R1 and R2. Is there a better data structure besides Set that I could use? Is there a more efficient approach in general? I've also found Point<-State mediation cumbersome. Is there another approach that I could try there? Thanks! Here is the code for my ConcretePlayer class. It might help explain how players produce new states via moves, using the StateProducer (which might need to become StateFactory or StateBuilder). public class ConcretePlayerGeneric extends AbstractPlayer { @Override public BinaryState makeMove() { // Given a move and the current state, produce a new state Point playerMove = super.strategy.evaluate(this); BinaryState currentState = super.getInGame().getBoard().getState(); return StateProducer.getState(this, playerMove, currentState); } } EDIT: I'm starting with normal TTT and moving to Quantum TTT. Given the framework, it should be as simple as creating several new Concrete classes and tweaking some things.

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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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  • How can I implement the Gale-Shapley stable marriage algorithm in Perl?

    - by srk
    Problem : We have equal number of men and women.each men has a preference score toward each woman. So do the woman for each man. each of the men and women have certain interests. Based on the interest we calculate the preference scores. So initially we have an input in a file having x columns. First column is the person(men/woman) id. id are nothing but 0.. n numbers.(first half are men and next half woman) the remaining x-1 columns will have the interests. these are integers too. now using this n by x-1 matrix... we have come up with a n by n/2 matrix. the new matrix has all men and woman as their rows and scores for opposite sex in columns. We have to sort the scores in descending order, also we need to know the id of person related to the scores after sorting. So here i wanted to use hash table. once we get the scores we need to make up pairs.. for which we need to follow some rules. My trouble is with the second matrix of n by n/2 that needs to give information of which man/woman has how much preference on a woman/man. I need these scores sorted so that i know who is the first preferred woman/man, 2nd preferred and so on for a man/woman. I hope to get good suggestions on the data structures i use.. I prefer php or perl. Thank you in advance Hey guys this is not an home work. This a little modified version of stable marriage algorithm. I have working solution. I am only working on optimizing my code. more info: It is very similar to stable marriage problem but here we need to calculate the scores based on the interests they share. So i have implemented it as the way you see in the wiki page http://en.wikipedia.org/wiki/Stable_marriage_problem. my problem is not solving the problem. i solved it and can run it. I am just trying to have a better solution. so i am asking suggestions on the type of data structure to use. Conceptually I tried using an array of hashes. where the array index give the person id and the hash in it gives the id's <= score's in sorted manner. I initially start with an array of hashes. now i sort the hashes on values, but i could not store the sorted hashes back in an array.So just stored the keys after sorting and used these to get the values from my initial unsorted hashes. Can we store the hashes after sorting ? Can you suggest a better structure ?

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  • How can I further optimize this color difference function?

    - by aLfa
    I have made this function to calculate color differences in the CIE Lab colorspace, but it lacks speed. Since I'm not a Java expert, I wonder if any Java guru around has some tips that can improve the speed here. The code is based on the matlab function mentioned in the comment block. /** * Compute the CIEDE2000 color-difference between the sample color with * CIELab coordinates 'sample' and a standard color with CIELab coordinates * 'std' * * Based on the article: * "The CIEDE2000 Color-Difference Formula: Implementation Notes, * Supplementary Test Data, and Mathematical Observations,", G. Sharma, * W. Wu, E. N. Dalal, submitted to Color Research and Application, * January 2004. * available at http://www.ece.rochester.edu/~gsharma/ciede2000/ */ public static double deltaE2000(double[] lab1, double[] lab2) { double L1 = lab1[0]; double a1 = lab1[1]; double b1 = lab1[2]; double L2 = lab2[0]; double a2 = lab2[1]; double b2 = lab2[2]; // Cab = sqrt(a^2 + b^2) double Cab1 = Math.sqrt(a1 * a1 + b1 * b1); double Cab2 = Math.sqrt(a2 * a2 + b2 * b2); // CabAvg = (Cab1 + Cab2) / 2 double CabAvg = (Cab1 + Cab2) / 2; // G = 1 + (1 - sqrt((CabAvg^7) / (CabAvg^7 + 25^7))) / 2 double CabAvg7 = Math.pow(CabAvg, 7); double G = 1 + (1 - Math.sqrt(CabAvg7 / (CabAvg7 + 6103515625.0))) / 2; // ap = G * a double ap1 = G * a1; double ap2 = G * a2; // Cp = sqrt(ap^2 + b^2) double Cp1 = Math.sqrt(ap1 * ap1 + b1 * b1); double Cp2 = Math.sqrt(ap2 * ap2 + b2 * b2); // CpProd = (Cp1 * Cp2) double CpProd = Cp1 * Cp2; // hp1 = atan2(b1, ap1) double hp1 = Math.atan2(b1, ap1); // ensure hue is between 0 and 2pi if (hp1 < 0) { // hp1 = hp1 + 2pi hp1 += 6.283185307179586476925286766559; } // hp2 = atan2(b2, ap2) double hp2 = Math.atan2(b2, ap2); // ensure hue is between 0 and 2pi if (hp2 < 0) { // hp2 = hp2 + 2pi hp2 += 6.283185307179586476925286766559; } // dL = L2 - L1 double dL = L2 - L1; // dC = Cp2 - Cp1 double dC = Cp2 - Cp1; // computation of hue difference double dhp = 0.0; // set hue difference to zero if the product of chromas is zero if (CpProd != 0) { // dhp = hp2 - hp1 dhp = hp2 - hp1; if (dhp > Math.PI) { // dhp = dhp - 2pi dhp -= 6.283185307179586476925286766559; } else if (dhp < -Math.PI) { // dhp = dhp + 2pi dhp += 6.283185307179586476925286766559; } } // dH = 2 * sqrt(CpProd) * sin(dhp / 2) double dH = 2 * Math.sqrt(CpProd) * Math.sin(dhp / 2); // weighting functions // Lp = (L1 + L2) / 2 - 50 double Lp = (L1 + L2) / 2 - 50; // Cp = (Cp1 + Cp2) / 2 double Cp = (Cp1 + Cp2) / 2; // average hue computation // hp = (hp1 + hp2) / 2 double hp = (hp1 + hp2) / 2; // identify positions for which abs hue diff exceeds 180 degrees if (Math.abs(hp1 - hp2) > Math.PI) { // hp = hp - pi hp -= Math.PI; } // ensure hue is between 0 and 2pi if (hp < 0) { // hp = hp + 2pi hp += 6.283185307179586476925286766559; } // LpSqr = Lp^2 double LpSqr = Lp * Lp; // Sl = 1 + 0.015 * LpSqr / sqrt(20 + LpSqr) double Sl = 1 + 0.015 * LpSqr / Math.sqrt(20 + LpSqr); // Sc = 1 + 0.045 * Cp double Sc = 1 + 0.045 * Cp; // T = 1 - 0.17 * cos(hp - pi / 6) + // + 0.24 * cos(2 * hp) + // + 0.32 * cos(3 * hp + pi / 30) - // - 0.20 * cos(4 * hp - 63 * pi / 180) double hphp = hp + hp; double T = 1 - 0.17 * Math.cos(hp - 0.52359877559829887307710723054658) + 0.24 * Math.cos(hphp) + 0.32 * Math.cos(hphp + hp + 0.10471975511965977461542144610932) - 0.20 * Math.cos(hphp + hphp - 1.0995574287564276334619251841478); // Sh = 1 + 0.015 * Cp * T double Sh = 1 + 0.015 * Cp * T; // deltaThetaRad = (pi / 3) * e^-(36 / (5 * pi) * hp - 11)^2 double powerBase = hp - 4.799655442984406; double deltaThetaRad = 1.0471975511965977461542144610932 * Math.exp(-5.25249016001879 * powerBase * powerBase); // Rc = 2 * sqrt((Cp^7) / (Cp^7 + 25^7)) double Cp7 = Math.pow(Cp, 7); double Rc = 2 * Math.sqrt(Cp7 / (Cp7 + 6103515625.0)); // RT = -sin(delthetarad) * Rc double RT = -Math.sin(deltaThetaRad) * Rc; // de00 = sqrt((dL / Sl)^2 + (dC / Sc)^2 + (dH / Sh)^2 + RT * (dC / Sc) * (dH / Sh)) double dLSl = dL / Sl; double dCSc = dC / Sc; double dHSh = dH / Sh; return Math.sqrt(dLSl * dLSl + dCSc * dCSc + dHSh * dHSh + RT * dCSc * dHSh); }

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  • How can i optimize this recursive method

    - by Tirdyr
    Hi there. I'm trying to make a word puzzle game, and for that i'm using a recursive method to find all possible words in the given letters. The letters is in a 4x4 board. Like this: ABCD EFGH HIJK LMNO The recursive method is called inside this loop: for (int y = 0; y < width; y++) { for (int x = 0; x < height; x++) { myScabble.Search(letters, y, x, width, height, "", covered, t); } } letters is a 2D array of chars. y & x is ints that shows where in the board width & height is also int, that tells the dimensions of the board "" is the string we are trying to make (the word) covered is an array of bools, to check if we allready used that square. t is a List (wich contains all the words to check against). The recursive method that need optimizing: public void Search(char[,] letters, int y, int x, int width, int height, string build, bool[,] covered, List<aWord> tt) { // Dont get outside the bounds if (y >= width || y < 0 || x >= height || x < 0) { return; } // Dont deal with allrady covered squares if (covered[x, y]) { return; } // Get Letter char letter = letters[x, y]; // Append string pass = build + letter; // check if its a possibel word //List<aWord> t = myWords.aWord.Where(w => w.word.StartsWith(pass)).ToList(); List<aWord> t = tt.Where(w => w.word.StartsWith(pass)).ToList(); // check if the list is emphty if (t.Count < 10 && t.Count != 0) { //stop point } if (t.Count == 0) { return; } // Check if its a complete word. if (t[0].word == pass) { //check if its allrdy present in the _found dictinary if (!_found.ContainsKey(pass)) { //if not add the word to the dictionary _found.Add(pass, true); } } // Check to see if there is more than 1 more that matches string pass // ie. are there more words to find. if (t.Count > 1) { // make a copy of the covered array bool[,] cov = new bool[height, width]; for (int i = 0; i < width; i++) { for (int a = 0; a < height; a++) { cov[a, i] = covered[a, i]; } } // Set the current square as covered. cov[x, y] = true; // Continue in all 8 directions. Search(letters, y + 1, x, width, height, pass, cov, t); Search(letters, y, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x + 1, width, height, pass, cov, t); Search(letters, y - 1, x, width, height, pass, cov, t); Search(letters, y, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x - 1, width, height, pass, cov, t); } } The code works as i expected it to do, however it is very slow.. it takes about 2 mins to find the words. EDIT: i clarified that the letters array is 2D

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  • Optimizing JS Array Search

    - by The.Anti.9
    I am working on a Browser-based media player which is written almost entirely in HTML 5 and JavaScript. The backend is written in PHP but it has one function which is to fill the playlist on the initial load. And the rest is all JS. There is a search bar that refines the playlist. I want it to refine as the person is typing, like most media players do. The only problem with this is that it is very slow and laggy as there are about 1000 songs in the whole program and there is likely to be more as time goes on. The original playlist load is an ajax call to a PHP page that returns the results as JSON. Each item has 4 attirbutes: artist album file url I then loop through each object and add it to an array called playlist. At the end of the looping a copy of playlist is created, backup. This is so that I can refine the playlist variable when people refine their search, but still repopulated it from backup without making another server request. The method refine() is called when the user types a key into the searchbox. It flushes playlist and searches through each property (not including url) of each object in the backup array for a match in the string. If there is a match in any of the properties, it appends the information to a table that displays the playlist, and adds it to the object to playlist for access by the actual player. Code for the refine() method: function refine() { $('#loadinggif').show(); $('#library').html("<table id='libtable'><tr><th>Artist</th><th>Album</th><th>File</th><th>&nbsp;</th></tr></table>"); playlist = []; for (var j = 0; j < backup.length; j++) { var sfile = new String(backup[j].file); var salbum = new String(backup[j].album); var sartist = new String(backup[j].artist); if (sfile.toLowerCase().search($('#search').val().toLowerCase()) !== -1 || salbum.toLowerCase().search($('#search').val().toLowerCase()) !== -1 || sartist.toLowerCase().search($('#search').val().toLowerCase()) !== -1) { playlist.push(backup[j]); num = playlist.length-1; $("<tr></tr>").html("<td>" + num + "</td><td>" + sartist + "</td><td>" + salbum + "</td><td>" + sfile + "</td><td><a href='#' onclick='setplay(" + num +");'>Play</a></td>").appendTo('#libtable'); } } $('#loadinggif').hide(); } As I said before, for the first couple of letters typed, this is very slow and laggy. I am looking for ways to refine this to make it much faster and more smooth.

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  • JavaScript Optimisation

    - by Jayie
    I am using JavaScript to work out all the combinations of badminton doubles matches from a given list of players. Each player teams up with everyone else. EG. If I have the following players a, b, c & d. Their combinations can be: a & b V c & d a & c V b & d a & d V b & c I am using the code below, which I wrote to do the job, but it's a little inefficient. It loops through the PLAYERS array 4 times finding every single combination (including impossible ones). It then sorts the game out into alphabetical order and stores it in the GAMES array if it doesn't already exist. I can then use the first half of the GAMES array to list all game combinations. The trouble is if I have any more than 8 players it runs really slowly because the combination growth is exponential. Does anyone know a better way or algorithm I could use? The more I think about it the more my brain hurts! var PLAYERS = ["a", "b", "c", "d", "e", "f", "g"]; var GAMES = []; var p1, p2, p3, p4, i1, i2, i3, i4, entry, found, i; var pos = 0; var TEAM1 = []; var TEAM2 = []; // loop through players 4 times to get all combinations for (i1 = 0; i1 < PLAYERS.length; i1++) { p1 = PLAYERS[i1]; for (i2 = 0; i2 < PLAYERS.length; i2++) { p2 = PLAYERS[i2]; for (i3 = 0; i3 < PLAYERS.length; i3++) { p3 = PLAYERS[i3]; for (i4 = 0; i4 < PLAYERS.length; i4++) { p4 = PLAYERS[i4]; if ((p1 != p2 && p1 != p3 && p1 != p4) && (p2 != p1 && p2 != p3 && p2 != p4) && (p3 != p1 && p3 != p2 && p3 != p4) && (p4 != p1 && p4 != p2 && p4 != p3)) { // sort teams into alphabetical order (so we can compare them easily later) TEAM1[0] = p1; TEAM1[1] = p2; TEAM2[0] = p3; TEAM2[1] = p4; TEAM1.sort(); TEAM2.sort(); // work out the game and search the array to see if it already exists entry = TEAM1[0] + " & " + TEAM1[1] + " v " + TEAM2[0] + " & " + TEAM2[1]; found = false; for (i=0; i < GAMES.length; i++) { if (entry == GAMES[i]) found = true; } // if the game is unique then store it if (!found) { GAMES[pos] = entry; document.write((pos+1) + ": " + GAMES[pos] + "<br>"); pos++; } } } } } } Thanks in advance. Jason.

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  • What approach to take for SIMD optimizations

    - by goldenmean
    Hi, I am trying to optimize below code for SIMD operations (8way/4way/2way SIMD whiechever possible and if it gives gains in performance) I am tryin to analyze it first on paper to understand the algorithm used. How can i optimize it for SIMD:- void idct(uint8_t *dst, int stride, int16_t *input, int type) { int16_t *ip = input; uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; int A, B, C, D, Ad, Bd, Cd, Dd, E, F, G, H; int Ed, Gd, Add, Bdd, Fd, Hd; int i; /* Inverse DCT on the rows now */ for (i = 0; i < 8; i++) { /* Check for non-zero values */ if ( ip[0] | ip[1] | ip[2] | ip[3] | ip[4] | ip[5] | ip[6] | ip[7] ) { A = M(xC1S7, ip[1]) + M(xC7S1, ip[7]); B = M(xC7S1, ip[1]) - M(xC1S7, ip[7]); C = M(xC3S5, ip[3]) + M(xC5S3, ip[5]); D = M(xC3S5, ip[5]) - M(xC5S3, ip[3]); Ad = M(xC4S4, (A - C)); Bd = M(xC4S4, (B - D)); Cd = A + C; Dd = B + D; E = M(xC4S4, (ip[0] + ip[4])); F = M(xC4S4, (ip[0] - ip[4])); G = M(xC2S6, ip[2]) + M(xC6S2, ip[6]); H = M(xC6S2, ip[2]) - M(xC2S6, ip[6]); Ed = E - G; Gd = E + G; Add = F + Ad; Bdd = Bd - H; Fd = F - Ad; Hd = Bd + H; /* Final sequence of operations over-write original inputs. */ ip[0] = (int16_t)(Gd + Cd) ; ip[7] = (int16_t)(Gd - Cd ); ip[1] = (int16_t)(Add + Hd); ip[2] = (int16_t)(Add - Hd); ip[3] = (int16_t)(Ed + Dd) ; ip[4] = (int16_t)(Ed - Dd ); ip[5] = (int16_t)(Fd + Bdd); ip[6] = (int16_t)(Fd - Bdd); } ip += 8; /* next row */ } ip = input; for ( i = 0; i < 8; i++) { /* Check for non-zero values (bitwise or faster than ||) */ if ( ip[1 * 8] | ip[2 * 8] | ip[3 * 8] | ip[4 * 8] | ip[5 * 8] | ip[6 * 8] | ip[7 * 8] ) { A = M(xC1S7, ip[1*8]) + M(xC7S1, ip[7*8]); B = M(xC7S1, ip[1*8]) - M(xC1S7, ip[7*8]); C = M(xC3S5, ip[3*8]) + M(xC5S3, ip[5*8]); D = M(xC3S5, ip[5*8]) - M(xC5S3, ip[3*8]); Ad = M(xC4S4, (A - C)); Bd = M(xC4S4, (B - D)); Cd = A + C; Dd = B + D; E = M(xC4S4, (ip[0*8] + ip[4*8])) + 8; F = M(xC4S4, (ip[0*8] - ip[4*8])) + 8; if(type==1){ //HACK E += 16*128; F += 16*128; } G = M(xC2S6, ip[2*8]) + M(xC6S2, ip[6*8]); H = M(xC6S2, ip[2*8]) - M(xC2S6, ip[6*8]); Ed = E - G; Gd = E + G; Add = F + Ad; Bdd = Bd - H; Fd = F - Ad; Hd = Bd + H; /* Final sequence of operations over-write original inputs. */ if(type==0){ ip[0*8] = (int16_t)((Gd + Cd ) >> 4); ip[7*8] = (int16_t)((Gd - Cd ) >> 4); ip[1*8] = (int16_t)((Add + Hd ) >> 4); ip[2*8] = (int16_t)((Add - Hd ) >> 4); ip[3*8] = (int16_t)((Ed + Dd ) >> 4); ip[4*8] = (int16_t)((Ed - Dd ) >> 4); ip[5*8] = (int16_t)((Fd + Bdd ) >> 4); ip[6*8] = (int16_t)((Fd - Bdd ) >> 4); }else if(type==1){ dst[0*stride] = cm[(Gd + Cd ) >> 4]; dst[7*stride] = cm[(Gd - Cd ) >> 4]; dst[1*stride] = cm[(Add + Hd ) >> 4]; dst[2*stride] = cm[(Add - Hd ) >> 4]; dst[3*stride] = cm[(Ed + Dd ) >> 4]; dst[4*stride] = cm[(Ed - Dd ) >> 4]; dst[5*stride] = cm[(Fd + Bdd ) >> 4]; dst[6*stride] = cm[(Fd - Bdd ) >> 4]; }else{ dst[0*stride] = cm[dst[0*stride] + ((Gd + Cd ) >> 4)]; dst[7*stride] = cm[dst[7*stride] + ((Gd - Cd ) >> 4)]; dst[1*stride] = cm[dst[1*stride] + ((Add + Hd ) >> 4)]; dst[2*stride] = cm[dst[2*stride] + ((Add - Hd ) >> 4)]; dst[3*stride] = cm[dst[3*stride] + ((Ed + Dd ) >> 4)]; dst[4*stride] = cm[dst[4*stride] + ((Ed - Dd ) >> 4)]; dst[5*stride] = cm[dst[5*stride] + ((Fd + Bdd ) >> 4)]; dst[6*stride] = cm[dst[6*stride] + ((Fd - Bdd ) >> 4)]; } } else { if(type==0){ ip[0*8] = ip[1*8] = ip[2*8] = ip[3*8] = ip[4*8] = ip[5*8] = ip[6*8] = ip[7*8] = ((xC4S4 * ip[0*8] + (IdctAdjustBeforeShift<<16))>>20); }else if(type==1){ dst[0*stride]= dst[1*stride]= dst[2*stride]= dst[3*stride]= dst[4*stride]= dst[5*stride]= dst[6*stride]= dst[7*stride]= cm[128 + ((xC4S4 * ip[0*8] + (IdctAdjustBeforeShift<<16))>>20)]; }else{ if(ip[0*8]){ int v= ((xC4S4 * ip[0*8] + (IdctAdjustBeforeShift<<16))>>20); dst[0*stride] = cm[dst[0*stride] + v]; dst[1*stride] = cm[dst[1*stride] + v]; dst[2*stride] = cm[dst[2*stride] + v]; dst[3*stride] = cm[dst[3*stride] + v]; dst[4*stride] = cm[dst[4*stride] + v]; dst[5*stride] = cm[dst[5*stride] + v]; dst[6*stride] = cm[dst[6*stride] + v]; dst[7*stride] = cm[dst[7*stride] + v]; } } } ip++; /* next column */ dst++; } }

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  • WPF, how can I optimize lines and circles drawing ?

    - by Aurélien Ribon
    Hello ! I am developping an application where I need to draw a graph on the screen. For this purpose, I use a Canvas and I put Controls on it. An example of such a draw as shown in the app can be found here : http://free0.hiboox.com/images/1610/d82e0b7cc3521071ede601d3542c7bc5.png It works fine for simple graphs, but I also want to be able to draw very large graphs (hundreds of nodes). And when I try to draw a very large graph, it takes a LOT of time to render. My problem is that the code is not optimized at all, I just wanted it to work. Until now, I have a Canvas on the one hand, and multiple Controls on the other hands. Actually, circles and lines are listed in collections, and for each item of these collections, I use a ControlTemplate, defining a red circle, a black circle, a line, etc. Here is an example, the definition of a graph circle : <!-- STYLE : DISPLAY DATA NODE --> <Style TargetType="{x:Type flow.elements:DisplayNode}"> <Setter Property="Canvas.Left" Value="{Binding X, RelativeSource={RelativeSource Self}}" /> <Setter Property="Canvas.Top" Value="{Binding Y, RelativeSource={RelativeSource Self}}" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type flow.elements:DisplayNode}"> <!--TEMPLATE--> <Grid x:Name="grid" Margin="-30,-30,0,0"> <Ellipse x:Name="selectionEllipse" StrokeThickness="0" Width="60" Height="60" Opacity="0" IsHitTestVisible="False"> <Ellipse.Fill> <RadialGradientBrush> <GradientStop Color="Black" Offset="0.398" /> <GradientStop Offset="1" /> </RadialGradientBrush> </Ellipse.Fill> </Ellipse> <Ellipse Stroke="Black" Width="30" Height="30" x:Name="ellipse"> <Ellipse.Fill> <LinearGradientBrush EndPoint="0,1"> <GradientStop Offset="0" Color="White" /> <GradientStop Offset="1.5" Color="LightGray" /> </LinearGradientBrush> </Ellipse.Fill> </Ellipse> <TextBlock x:Name="tblock" Text="{Binding NodeName, RelativeSource={RelativeSource Mode=TemplatedParent}}" Foreground="Black" VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="10.667" /> </Grid> <!--TRIGGERS--> <ControlTemplate.Triggers> <!--DATAINPUT--> <MultiTrigger> <MultiTrigger.Conditions> <Condition Property="SkinMode" Value="NODETYPE" /> <Condition Property="NodeType" Value="DATAINPUT" /> </MultiTrigger.Conditions> <Setter TargetName="tblock" Property="Foreground" Value="White" /> <Setter TargetName="ellipse" Property="Fill"> <Setter.Value> <LinearGradientBrush EndPoint="0,1"> <GradientStop Offset="-0.5" Color="White" /> <GradientStop Offset="1" Color="Black" /> </LinearGradientBrush> </Setter.Value> </Setter> </MultiTrigger> <!--DATAOUTPUT--> <MultiTrigger> <MultiTrigger.Conditions> <Condition Property="SkinMode" Value="NODETYPE" /> <Condition Property="NodeType" Value="DATAOUTPUT" /> </MultiTrigger.Conditions> <Setter TargetName="tblock" Property="Foreground" Value="White" /> <Setter TargetName="ellipse" Property="Fill"> <Setter.Value> <LinearGradientBrush EndPoint="0,1"> <GradientStop Offset="-0.5" Color="White" /> <GradientStop Offset="1" Color="Black" /> </LinearGradientBrush> </Setter.Value> </Setter> </MultiTrigger> ....... THERE IS A TOTAL OF 7 MULTITRIGGERS ....... </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> Also, the lines are drawn using the Line Control. <!-- STYLE : DISPLAY LINK --> <Style TargetType="{x:Type flow.elements:DisplayLink}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type flow.elements:DisplayLink}"> <!--TEMPLATE--> <Line X1="{Binding X1, RelativeSource={RelativeSource TemplatedParent}}" X2="{Binding X2, RelativeSource={RelativeSource TemplatedParent}}" Y1="{Binding Y1, RelativeSource={RelativeSource TemplatedParent}}" Y2="{Binding Y2, RelativeSource={RelativeSource TemplatedParent}}" Stroke="Gray" StrokeThickness="2" x:Name="line" /> <!--TRIGGERS--> <ControlTemplate.Triggers> <!--BRANCH : ASSERTION--> <MultiTrigger> <MultiTrigger.Conditions> <Condition Property="SkinMode" Value="BRANCHTYPE" /> <Condition Property="BranchType" Value="ASSERTION" /> </MultiTrigger.Conditions> <Setter TargetName="line" Property="Stroke" Value="#E0E0E0" /> </MultiTrigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> So, I need your advices. How can I drastically improve the rendering performances ? Should I define each MultiTrigger circle rendering possibility in its own ControlTemplate instead ? Is there a better line drawing technique ? Should I open a DrawingContext and draw everything in one control, instead of having hundreds of controls ?

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  • Practical refactoring using unit tests

    - by awhite
    Having just read the first four chapters of Refactoring: Improving the Design of Existing Code, I embarked on my first refactoring and almost immediately came to a roadblock. It stems from the requirement that before you begin refactoring, you should put unit tests around the legacy code. That allows you to be sure your refactoring didn't change what the original code did (only how it did it). So my first question is this: how do I unit-test a method in legacy code? How can I put a unit test around a 500 line (if I'm lucky) method that doesn't do just one task? It seems to me that I would have to refactor my legacy code just to make it unit-testable. Does anyone have any experience refactoring using unit tests? And, if so, do you have any practical examples you can share with me? My second question is somewhat hard to explain. Here's an example: I want to refactor a legacy method that populates an object from a database record. Wouldn't I have to write a unit test that compares an object retrieved using the old method, with an object retrieved using my refactored method? Otherwise, how would I know that my refactored method produces the same results as the old method? If that is true, then how long do I leave the old deprecated method in the source code? Do I just whack it after I test a few different records? Or, do I need to keep it around for a while in case I encounter a bug in my refactored code? Lastly, since a couple people have asked...the legacy code was originally written in VB6 and then ported to VB.NET with minimal architecture changes.

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  • Newbie question: When to use extern "C" { //code } ?

    - by Russel
    Hello, Maybe I'm not understanding the differences between C and C++, but when and why do we need to use: extern "C" { ? Apparently its a "linkage convention"? I read about it briefly and noticed that all the .h header files included with MSVS surround their code with it. What type of code exactly is "C code" and NOT "C++ code"? I thought C++ included all C code? I'm guessing that this is not the case and that C++ is different and that standard features/functions exist in one or the other but not both (ie: printf is C and cout is C++), but that C++ is backwards compatible though the extern "C" declaration. Is this correct? My next question depends on the answer to the first, but I'll ask it here anyway: Since MSVS header files that are written in C are surrounded by extern "C" { ... }, when would you ever need to use this yourself in your own code? If your code is C code and you are trying to compile it in a C++ compiler, shouldn't it work without problem because all the standard h files you include will already have the extern "C" thing in them with the C++ compiler? Do you have to use this when compiling in C++ but linking to alteady built C libraries or something? Please help clarify this for me... Thanks! --Keith

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  • What is your personal approach/take on commenting?

    - by Trae
    Duplicate What are your hard rules about commenting? A Developer I work with had some things to say about commenting that were interesting to me (see below). What is your personal approach/take on commenting? "I don't add comments to code unless its a simple heading or there's a platform-bug or a necessary work-around that isn't obvious. Code can change and comments may become misleading. Code should be self-documenting in its use of descriptive names and its logical organization - and its solutions should be the cleanest/simplest way to perform a given task. If a programmer can't tell what a program does by only reading the code, then he's not ready to alter it. Commenting tends to be a crutch for writing something complex or non-obvious - my goal is to always write clean and simple code." "I think there a few camps when it comes to commenting, the enterprisey-type who think they're writing an API and some grand code-library that will be used for generations to come, the craftsman-like programmer that thinks code says what it does clearer than a comment could, and novices that write verbose/unclear code so as to need to leave notes to themselves as to why they did something."

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  • Displaying code with <pre> tags.

    - by iMaster
    Currently I'm using <pre><code> code here </code><pre> to display code. I'm pulling this information from a DB for a blog. The problem I'm having is that some of the code isn't showing. For example, in the source code I have this: <pre><code><br /> echo '<ul class="mylist"><li><ul class="left">'; foreach($nameArray as $name) { if($countervar == $half) { echo '</ul></li>'; echo'<li><ul class="right">'; } echo '<li>$name</li>'; ++$i; } echo '</ul></li>'; echo '</ul>'; ?> But all that shows up is this: echo ''; foreach($nameArray as $name) { if($countervar == $half) { echo ''; echo''; } echo '$name'; ++$i; } echo ' An there's some really weird formatting/spacing issues as well. Any ideas as to what is causing this? I should also mention that some of the other sets of code show up just fine.

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  • avoiding code duplication in Rails 3 models

    - by Dustin Frazier
    I'm working on a Rails 3.1 application where there are a number of different enum-like models that are stored in the database. There is a lot of identical code in these models, as well as in the associated controllers and views. I've solved the code duplication for the controllers and views via a shared parent controller class and the new view/layout inheritance that's part of Rails 3. Now I'm trying to solve the code duplication in the models, and I'm stuck. An example of one of my enum models is as follows: class Format < ActiveRecord::Base has_and_belongs_to_many :videos attr_accessible :name validates :name, presence: true, length: { maximum: 20 } before_destroy :verify_no_linked_videos def verify_no_linked_videos unless self.videos.empty? self.errors[:base] << "Couldn't delete format with associated videos." raise ActiveRecord::RecordInvalid.new self end end end I have four or five other classes with nearly identical code (the association declaration being the only difference). I've tried creating a module with the shared code that they all include (which seems like the Ruby Way), but much of the duplicate code relies on ActiveRecord, so the methods I'm trying to use in the module (validate, attr_accessible, etc.) aren't available. I know about ActiveModel, but that doesn't get me all the way there. I've also tried creating a common, non-persistent parent class that subclasses ActiveRecord::Base, but all of the code I've seen to accomplish this assumes that you won't have subclasses of your non-persistent class that do persist. Any suggestions for how best to avoid duplicating these identical lines of code across many different enum models?

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  • Can't view order in magento

    - by koko
    Hi, I've been setting up a fresh magento 1.4.0.1 install, working great so far. I did some test orders just to see. Everything works fine, but when I click on "view order" under "my orders", I get a bunch of error messages: There has been an error processing your request Notice: iconv_substr() [function.iconv-substr]: Unknown error (0) in /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Helper/String.php on line 98 Trace: #0 [internal function]: mageCoreErrorHandler(8, 'iconv_substr() ...', '/data/web/A1423...', 98, Array) #1 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Helper/String.php(98): iconv_substr('1', 0, 50, 'UTF-8') #2 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Helper/String.php(173): Mage_Core_Helper_String-substr('1', 0, 50) #3 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Helper/String.php(112): Mage_Core_Helper_String-str_split('1', 50) #4 /data/web/A14237/htdocs/magento/app/design/frontend/base/default/template/sales/order/items/renderer/default.phtml(58): Mage_Core_Helper_String-splitInjection('1') #5 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(189): include('/data/web/A1423...') #6 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(225): Mage_Core_Block_Template-fetchView('frontend/base/d...') #7 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(242): Mage_Core_Block_Template-renderView() #8 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Core_Block_Template-_toHtml() #9 /data/web/A14237/htdocs/magento/app/code/core/Mage/Sales/Block/Items/Abstract.php(137): Mage_Core_Block_Abstract-toHtml() #10 /data/web/A14237/htdocs/magento/app/design/frontend/base/default/template/sales/order/items.phtml(52): Mage_Sales_Block_Items_Abstract-getItemHtml(Object(Mage_Sales_Model_Order_Item)) #11 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(189): include('/data/web/A1423...') #12 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(225): Mage_Core_Block_Template-fetchView('frontend/base/d...') #13 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(242): Mage_Core_Block_Template-renderView() #14 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Core_Block_Template-_toHtml() #15 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(516): Mage_Core_Block_Abstract-toHtml() #16 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(467): Mage_Core_Block_Abstract-_getChildHtml('order_items', true) #17 /data/web/A14237/htdocs/magento/app/design/frontend/base/default/template/sales/order/view.phtml(64): Mage_Core_Block_Abstract-getChildHtml('order_items') #18 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(189): include('/data/web/A1423...') #19 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(225): Mage_Core_Block_Template-fetchView('frontend/base/d...') #20 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(242): Mage_Core_Block_Template-renderView() #21 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Core_Block_Template-_toHtml() #22 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(516): Mage_Core_Block_Abstract-toHtml() #23 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(463): Mage_Core_Block_Abstract-_getChildHtml('sales.order.vie...', true) #24 /data/web/A14237/htdocs/magento/app/code/core/Mage/Page/Block/Html/Wrapper.php(52): Mage_Core_Block_Abstract-getChildHtml('', true, true) #25 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Page_Block_Html_Wrapper-_toHtml() #26 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Text/List.php(43): Mage_Core_Block_Abstract-toHtml() #27 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Core_Block_Text_List-_toHtml() #28 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(516): Mage_Core_Block_Abstract-toHtml() #29 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(467): Mage_Core_Block_Abstract-_getChildHtml('content', true) #30 /data/web/A14237/htdocs/magento/app/design/frontend/base/default/template/page/2columns-left.phtml(48): Mage_Core_Block_Abstract-getChildHtml('content') #31 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(189): include('/data/web/A1423...') #32 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(225): Mage_Core_Block_Template-fetchView('frontend/base/d...') #33 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Template.php(242): Mage_Core_Block_Template-renderView() #34 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Block/Abstract.php(674): Mage_Core_Block_Template-_toHtml() #35 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Model/Layout.php(536): Mage_Core_Block_Abstract-toHtml() #36 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Controller/Varien/Action.php(389): Mage_Core_Model_Layout-getOutput() #37 /data/web/A14237/htdocs/magento/app/code/core/Mage/Sales/controllers/OrderController.php(100): Mage_Core_Controller_Varien_Action-renderLayout() #38 /data/web/A14237/htdocs/magento/app/code/core/Mage/Sales/controllers/OrderController.php(136): Mage_Sales_OrderController-_viewAction() #39 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Sales_OrderController-viewAction() #40 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action-dispatch('view') #41 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Controller/Varien/Front.php(177): Mage_Core_Controller_Varien_Router_Standard-match(Object(Mage_Core_Controller_Request_Http)) #42 /data/web/A14237/htdocs/magento/app/code/core/Mage/Core/Model/App.php(304): Mage_Core_Controller_Varien_Front-dispatch() #43 /data/web/A14237/htdocs/magento/app/Mage.php(596): Mage_Core_Model_App-run(Array) #44 /data/web/A14237/htdocs/magento/index.php(78): Mage::run('', 'store') #45 {main} gtx, koko

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  • What is "elegant" code?

    - by Breton
    I see a lot of lip service and talk about the most "elegant" way to do this or that. I think if you spend enough time programming you begin to obtain a sort of intuitive feel for what it is we call "elegance". But I'm curious. Even if we can look at a bit of code, and say instinctively "That's elegant", or "That's messy", I wonder if any of us really understands what that means. Is there a precise definition for this "elegance" we keep referring to? If there is, what is it? Now, what I mean by a precise definition, is a series of statements which can be used to derive questions about a peice of code, or a program as a whole, and determine objectively, or as objectively as possible, whether that code is "elegant" or not. May I assert, that perhaps no such definition exists, and it's all just personal preference. In this case, I ask you a slightly different question: Is there a better word for "elegance", or a better set of attributes to use for judging code quality that is perhaps more objective than merely appealing to individual intuition and taste? Perhaps code quality is a matter of taste, and the answer to both of my questions is "no". But I can't help but feel that we could be doing better than just expressing wishy washy feelings about our code quality. For example, user interface design is something that to a broad range of people looks for all the world like a field of study that oughtta be 100% subjective matter of taste. But this is shockingly and brutally not the case, and there are in fact many objective measures that can be applied to a user interface to determine its quality. A series of tests could be written to give a definitive and repeatable score to user interface quality. (See GOMS, for instance). Now, okay. is Elegance simply "code quality" or is it something more? Is it something that can be measured? Or is it a matter of taste? Does our profession have room for taste? Maybe I'm asking the wrong questions altogether. Help me out here. Bonus Round If there is such a thing as elegance in code, and that concept is useful, do you think that justifies classifying the field of programming as an "Art" capital A, or merely a "craft". Or is it just an engineering field populated by a bunch of wishful thinking humans? Consider this question in the light of your thoughts about the elegance question. Please note that there is a distinction between code which is considered "art" in itself, and code that was written merely in the service of creating an artful program. When I ask this question, I ask if the code itself justifies calling programming an art. Bounty Note I liked the answers to this question so much, I think I'd like to make a photographic essay book from it. Released as a free PDF, and published on some kind of on demand printing service of course, such as "zazz" or "tiggle" or "printley" or something . I'd like some more answers, please!

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  • What is Search Engine Optimization - An Art Or Science?

    As ridiculous and as outrageous as this question might sound, there has been no evident and obvious answer to this. The fact that the process of Search Engine optimization is an art or mere science is something that web scholars have been debating for a long time, and to people's amusement, have still not come to a concrete conclusion. One important step that was taken towards having this question answered or finding an answer to it was asking all the service providers about the way they think of SEO.

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  • Search Engine Optimization and SEO Services - What Do They Offer?

    Search engine optimization involves using the Internet as a marketing tool. Companies that are using the Internet to attract customers desire to optimize their exposure to potential to customers. In order to best advantage of SEO, it is recommended that you hire a professional service that can implement programs to evaluate the optimum marketing potential of the Internet. When considering hiring a company to assist you in this process it is important to understand how such services work.

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  • Why Does On-Page Search Engine Optimization Work So Well?

    On-page search engine optimization has been around since an inordinately long time - probably it is the first kind of SEO that marketers began to use - but it is only lately that people have begun to understand its great efficacy in bolstering the prospects of any website. The term is used to describe all methods you use on the page of the website in order to enhance its prospects with the search engines.

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  • What Are the Top 4 Search Engine Optimization Techniques of Today?

    Today, with the over-whelming competitions among the web masters in competing for customers to increase their sales and profit, finding ways to increase to optimize their websites is not really very difficult. There are whole lots of SEO (Search engine optimization) techniques which can be found over the internet today, which majority of them are really very user friendly which even a novice web-master with limited HTML knowledge find it not that difficult to get the most out of it as long as they have the will to learn and improve in their search ranking.

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  • How to Cut Search Engine Optimization Cost Down For Backlink Building?

    How much do you spend to get your high backlinks? I am guessing a good amount if you are paying a service to do it for you, or if you are buying backlink packets made by other people and paying a monthly fee. You can cut your search engine optimization cost greatly with some easy to use software, and even outsource the work for much cheaper than other SEO services.

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