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  • Rounding a positive number to a power of another number

    - by Sagekilla
    I'm trying to round a number to the next smallest power of another number. The number I'm trying to round is always positive. I'm not particular on which direction it rounds, but I prefer downwards if possible. I would like to be able to round towards arbitrary bases, but the ones I'm most concerned with at the moment is base 2 and fractional powers of 2 like 2^(1/2), 2^(1/4), and so forth. Here's my current algorithm for base 2. The log2 I multiply by is actually the inverse of log2: double roundBaseTwo(double x) { return 1.0 / (1 << (int)((log(x) * log2)) } Any help would be appreciated!

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  • convert javascript number to css value -- maximum number of trailing decimals

    - by philipp
    I am about to have some fun with the css transform matrix and javascript. At the moment everything is cool, except when a number becomes something like 0.000034e3344 after the to string conversion. Than the transform does not work. So I know that there is the Number.toFixed() method which actually solves the problem, but i ask myself how many trailing decimals make sense. So what is the highest value i can pass to the toFixed() method to get the most precise results? EDIT::: the exact number output was: 9.685539407532573e-20

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  • C# Random Number Generator getting stuck in a cycle

    - by Jean Azzopardi
    Hi, I am using .NET to create an artificial life program and I am using C#'s pseudo random class defined in a Singleton. The idea is that if I use the same random number generator throughout the application, I could merely save the seed and then reload from the seed to recompute a certain interesting run. public sealed class RandomNumberGenerator : Random { private static readonly RandomNumberGenerator instance = new RandomNumberGenerator(); RandomNumberGenerator() { } public static RandomNumberGenerator Instance { get { return instance; } } } I also wanted a method that could give me two different random numbers. public static Tuple<int, int> TwoDifferentRandomNumbers(this Random rnd, int minValue, int maxValue) { if (minValue >= maxValue) throw new ArgumentOutOfRangeException("maxValue", "maxValue must be greater than minValue"); if (minValue + 1 == maxValue) return Tuple.Create<int, int>(minValue, maxValue); int rnd1 = rnd.Next(minValue, maxValue); int rnd2 = rnd.Next(minValue, maxValue); while (rnd1 == rnd2) { rnd2 = rnd.Next(minValue, maxValue); } return Tuple.Create<int, int>(rnd1, rnd2); } The problem is that sometimes rnd.Next(minValue,maxValuealways returns minValue. If I breakpoint at this point and try creating a double and setting it to rnd.NextDouble(), it returns 0.0. Anyone know why this is happening? I know that it is a pseudo random number generator, but frankly, I hadn't expected it to lock at 0. The random number generator is being accessed from multiple threads... could this be the source of the problem?

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  • How can I make an even more random number in ActionScript 2.0

    - by Theo
    I write a piece of software that runs inside banner ads which generates millions of session IDs every day. For a long time I've known that the random number generator in Flash is't random enough to generate sufficiently unique IDs, so I've employed a number of tricks to get even more random numbers. However, in ActionScript 2.0 it's not easy, and I'm seeing more and more collisions, so I wonder if there is something I've overlooked. As far as I can tell the problem with Math.random() is that it's seeded by the system time, and when you have sufficient numbers of simultaneous attempts you're bound to see collisions. In ActionScript 3.0 I use the System.totalMemory, but there's no equivalent in ActionScript 2.0. AS3 also has Font.enumerateFonts, and a few other things that are different from system to system. On the server side I also add the IP address to the session ID, but even that isn't enough (for example, many large companies use a single proxy server and that means that thousands of people all have the same IP -- and since they tend to look at the same sites, with the same ads, roughly at the same time, there are many session ID collisions). What I need isn't something perfectly random, just something that is random enough to dilute the randomness I get from Math.random(). Think of it this way: there is a certain chance that two people will generate the same random number sequence using only Math.random(), but the chance of two people generating the same sequence and having, say, the exact same list of fonts is significantly lower. I cannot rely on having sufficient script access to use ExternalInterface to get hold of things like the user agent, or the URL of the page. I don't need suggestions of how to do it in AS3, or any other system, only AS2 -- using only what's available in the standard APIs. The best I've come up with so far is to use the list of microphones (Microphone.names), but I've also tried to make some fingerprinting using some of the properties in System.capabilities, I'm not sure how much randomness I can get out of that though so I'm not using that at the moment. I hope I've overlooked something.

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  • Algorithm to calculate the number of divisors of a given number

    - by sker
    What would be the most optimal algorithm (performance-wise) to calculate the number of divisors of a given number? It'll be great if you could provide pseudocode or a link to some example. EDIT: All the answers have been very helpful, thank you. I'm implementing the Sieve of Atkin and then I'm going to use something similar to what Jonathan Leffler indicated. The link posted by Justin Bozonier has further information on what I wanted.

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  • number several equations with only one number

    - by Tim
    Hi, How can I number several equations in a align environment using only one number? For example \begin{align} w^T x_i + b \geqslant 1-\xi_i \text{ if } y_i=1, \nonumber \\ w^T x_i + b \leqslant -1+\xi_i \text{ if } y_i=-1, \end{align} The numbering will appear next to the second equation. But it would be better if it appears between the lines of the two equations. In this case how to label this group of equations for later referring to? Thanks and regards!

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  • Warning: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variabl

    - by Thomas
    Hi, I'm working with PHP PDO and I have the following problem: Warning: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens in /var/www/site/classes/enterprise.php on line 63 Here is my code: public function getCompaniesByCity(City $city, $options = null) { $database = Connection::getConnection(); if(empty($options)) { $statement = $database-prepare("SELECT * FROM empresas WHERE empresas.cidades_codigo = ?"); $statement-bindValue(1, $city-getId()); } else { $sql = "SELECT * FROM empresas INNER JOIN prods_empresas ON prods_empresas.empresas_codigo = empresas.codigo WHERE "; foreach($options as $option) { $sql .= 'prods_empresas.produtos_codigo = ? OR '; } $sql = substr($sql, 0, -4); $sql .= ' AND empresas.cidades_codigo = ?'; $statement = $database-prepare($sql); echo $sql; foreach($options as $i = $option) { $statement-bindValue($i + 1, $option-getId()); } $statement-bindValue(count($options), $city-getId()); } $statement-execute(); $objects = $statement-fetchAll(PDO::FETCH_OBJ); $companies = array(); if(!empty($objects)) { foreach($objects as $object) { $data = array( 'id' = $object-codigo, 'name' = $object-nome, 'link' = $object-link, 'email' = $object-email, 'details' = $object-detalhes, 'logo' = $object-logo ); $enterprise = new Enterprise($data); array_push($companies, $enterprise); } return $companies; } } Thank you very much!

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  • How to get element order number

    - by martin-masiar
    Hello everyone, how can i get order number of some element by javascript/jquery? <ul> <li>Anton</li> <li class="abc">Victor</li> <li class="abc">Simon</li> <li>Adam</li> <li>Peter</li> <li class="abc">Tom</li> </ul> There is 3xli with abc class. Now I need to get order(sequence) number of Simon li. Thanks in advance

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  • T-SQL - Left Outer Joins - Filters in the where clause versus the on clause.

    - by Greg Potter
    I am trying to compare two tables to find rows in each table that is not in the other. Table 1 has a groupby column to create 2 sets of data within table one. groupby number ----------- ----------- 1 1 1 2 2 1 2 2 2 4 Table 2 has only one column. number ----------- 1 3 4 So Table 1 has the values 1,2,4 in group 2 and Table 2 has the values 1,3,4. I expect the following result when joining for Group 2: `Table 1 LEFT OUTER Join Table 2` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 2 2 NULL `Table 2 LEFT OUTER Join Table 1` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- NULL NULL 3 The only way I can get this to work is if I put a where clause for the first join: PRINT 'Table 1 LEFT OUTER Join Table 2, with WHERE clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number --****************************** WHERE table1.groupby = 2 AND table2.number IS NULL and a filter in the ON for the second: PRINT 'Table 2 LEFT OUTER Join Table 1, with ON clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number AND table1.groupby = 2 --****************************** WHERE table1.number IS NULL Can anyone come up with a way of not using the filter in the on clause but in the where clause? The context of this is I have a staging area in a database and I want to identify new records and records that have been deleted. The groupby field is the equivalent of a batchid for an extract and I am comparing the latest extract in a temp table to a the batch from yesterday stored in a partioneds table, which also has all the previously extracted batches as well. Code to create table 1 and 2: create table table1 (number int, groupby int) create table table2 (number int) insert into table1 (number, groupby) values (1, 1) insert into table1 (number, groupby) values (2, 1) insert into table1 (number, groupby) values (1, 2) insert into table2 (number) values (1) insert into table1 (number, groupby) values (2, 2) insert into table2 (number) values (3) insert into table1 (number, groupby) values (4, 2) insert into table2 (number) values (4) EDIT: A bit more context - depending on where I put the filter I different results. As stated above the where clause gives me the correct result in one state and the ON in the other. I am looking for a consistent way of doing this. Where - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number --****************************** WHERE table1.groupby = 2 AND table2.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 2 2 NULL On - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number AND table1.groupby = 2 --****************************** WHERE table2.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 1 1 NULL 2 2 NULL 1 2 NULL Where (table 2 this time) - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number AND table1.groupby = 2 --****************************** WHERE table1.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- NULL NULL 3 On - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number --****************************** WHERE table1.number IS NULL AND table1.groupby = 2 Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- (0) rows returned

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  • PHP - Math - Round Number Function

    - by aSeptik
    Hi All guys! this time i have a math question for you! Assuming we have three numbers one is the Number of Votes the second is the Total Values and the last is the Units Ratings. units_ratings can be a number from 1 to 10; if ( total_values / units_ratings != number_of_votes ) { //do something for let the "number_of_votes" fit the division! } I ask this to you, cause i want know the best (fastest) way of achieve this! Thanks!

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  • Noob Droid Question regarding random number

    - by Pete Herbert Penito
    Brand new to droid programming, but would love to learn as much as possible, so I finally got my emulator working correctly, I even got a hello world button to work, I'm attempting to make this button display a random number, I've googled this and came up with this code: Random generator = new Random(); int n = generator.nextInt(n); I fixed the Random function by including some Random java utility. I'm assuming this code above goes in the .java file of the project, so my button code looks as follows (tested and works): PopUpText.makeText(v.getContext(), "Hello World", PopUpText.LENGTH_LONG).show(); I figured I could replace "Hello World" with n to display the number in the box, however the following error is stopping the compile: The local variable n may not have been initialized Any ideas why this is happening? Any advice would be hugely appreciated.

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  • Fastest method to define whether a number is a triangular number

    - by psihodelia
    A triangular number is the sum of the n natural numbers from 1 to n. What is the fastest method to find whether a given positive integer number is a triangular one? I suppose, there must be a hidden pattern in a binary representation of such numbers (like if you need to find whether a number is even/odd you check its least significant bit). Here is a cut of the first 1200th up to 1300th triangular numbers, you can easily see a bit-pattern here (if not, try to zoom out): (720600, '10101111111011011000') (721801, '10110000001110001001') (723003, '10110000100000111011') (724206, '10110000110011101110') (725410, '10110001000110100010') (726615, '10110001011001010111') (727821, '10110001101100001101') (729028, '10110001111111000100') (730236, '10110010010001111100') (731445, '10110010100100110101') (732655, '10110010110111101111') (733866, '10110011001010101010') (735078, '10110011011101100110') (736291, '10110011110000100011') (737505, '10110100000011100001') (738720, '10110100010110100000') (739936, '10110100101001100000') (741153, '10110100111100100001') (742371, '10110101001111100011') (743590, '10110101100010100110') (744810, '10110101110101101010') (746031, '10110110001000101111') (747253, '10110110011011110101') (748476, '10110110101110111100') (749700, '10110111000010000100') (750925, '10110111010101001101') (752151, '10110111101000010111') (753378, '10110111111011100010') (754606, '10111000001110101110') (755835, '10111000100001111011') (757065, '10111000110101001001') (758296, '10111001001000011000') (759528, '10111001011011101000') (760761, '10111001101110111001') (761995, '10111010000010001011') (763230, '10111010010101011110') (764466, '10111010101000110010') (765703, '10111010111100000111') (766941, '10111011001111011101') (768180, '10111011100010110100') (769420, '10111011110110001100') (770661, '10111100001001100101') (771903, '10111100011100111111') (773146, '10111100110000011010') (774390, '10111101000011110110') (775635, '10111101010111010011') (776881, '10111101101010110001') (778128, '10111101111110010000') (779376, '10111110010001110000') (780625, '10111110100101010001') (781875, '10111110111000110011') (783126, '10111111001100010110') (784378, '10111111011111111010') (785631, '10111111110011011111') (786885, '11000000000111000101') (788140, '11000000011010101100') (789396, '11000000101110010100') (790653, '11000001000001111101') (791911, '11000001010101100111') (793170, '11000001101001010010') (794430, '11000001111100111110') (795691, '11000010010000101011') (796953, '11000010100100011001') (798216, '11000010111000001000') (799480, '11000011001011111000') (800745, '11000011011111101001') (802011, '11000011110011011011') (803278, '11000100000111001110') (804546, '11000100011011000010') (805815, '11000100101110110111') (807085, '11000101000010101101') (808356, '11000101010110100100') (809628, '11000101101010011100') (810901, '11000101111110010101') (812175, '11000110010010001111') (813450, '11000110100110001010') (814726, '11000110111010000110') (816003, '11000111001110000011') (817281, '11000111100010000001') (818560, '11000111110110000000') (819840, '11001000001010000000') (821121, '11001000011110000001') (822403, '11001000110010000011') (823686, '11001001000110000110') (824970, '11001001011010001010') (826255, '11001001101110001111') (827541, '11001010000010010101') (828828, '11001010010110011100') (830116, '11001010101010100100') (831405, '11001010111110101101') (832695, '11001011010010110111') (833986, '11001011100111000010') (835278, '11001011111011001110') (836571, '11001100001111011011') (837865, '11001100100011101001') (839160, '11001100110111111000') (840456, '11001101001100001000') (841753, '11001101100000011001') (843051, '11001101110100101011') (844350, '11001110001000111110') For example, can you also see a rotated normal distribution curve, represented by zeros between 807085 and 831405?

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  • Fastest way to pad a number in Java to a certain number of digits

    - by Martin
    Am trying to create a well-optimised bit of code to create number of X-digits in length (where X is read from a runtime properties file), based on a DB-generated sequence number (Y), which is then used a folder-name when saving a file. I've come up with three ideas so far, the fastest of which is the last one, but I'd appreciate any advice people may have on this... 1) Instantiate a StringBuilder with initial capacity X. Append Y. While length < X, insert a zero at pos zero. 2) Instantiate a StringBuilder with initial capacity X. While length < X, append a zero. Create a DecimalFormat based on StringBuilder value, and then format the number when it's needed. 3) Create a new int of Math.pow( 10, X ) and add Y. Use String.valueOf() on the new number and then substring(1) it. The second one can obviously be split into outside-loop and inside-loop sections. So, any tips? Using a for-loop of 10,000 iterations, I'm getting similar timings from the first two, and the third method is approximately ten-times faster. Does this seem correct? Full test-method code below... // Setup test variables int numDigits = 9; int testNumber = 724; int numIterations = 10000; String folderHolder = null; DecimalFormat outputFormat = new DecimalFormat( "#,##0" ); // StringBuilder test long before = System.nanoTime(); for ( int i = 0; i < numIterations; i++ ) { StringBuilder sb = new StringBuilder( numDigits ); sb.append( testNumber ); while ( sb.length() < numDigits ) { sb.insert( 0, 0 ); } folderHolder = sb.toString(); } long after = System.nanoTime(); System.out.println( "01: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" ); // DecimalFormat test before = System.nanoTime(); StringBuilder sb = new StringBuilder( numDigits ); while ( sb.length() < numDigits ) { sb.append( 0 ); } DecimalFormat formatter = new DecimalFormat( sb.toString() ); for ( int i = 0; i < numIterations; i++ ) { folderHolder = formatter.format( testNumber ); } after = System.nanoTime(); System.out.println( "02: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" ); // Substring test before = System.nanoTime(); int baseNum = (int)Math.pow( 10, numDigits ); for ( int i = 0; i < numIterations; i++ ) { int newNum = baseNum + testNumber; folderHolder = String.valueOf( newNum ).substring( 1 ); } after = System.nanoTime(); System.out.println( "03: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" );

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  • Calculate the number of ways to roll a certain number

    - by helloworld
    I'm a high school Computer Science student, and today I was given a problem to: Program Description: There is a belief among dice players that in throwing three dice a ten is easier to get than a nine. Can you write a program that proves or disproves this belief? Have the computer compute all the possible ways three dice can be thrown: 1 + 1 + 1, 1 + 1 + 2, 1 + 1 + 3, etc. Add up each of these possibilities and see how many give nine as the result and how many give ten. If more give ten, then the belief is proven. I quickly worked out a brute force solution, as such int sum,tens,nines; tens=nines=0; for(int i=1;i<=6;i++){ for(int j=1;j<=6;j++){ for(int k=1;k<=6;k++){ sum=i+j+k; //Ternary operators are fun! tens+=((sum==10)?1:0); nines+=((sum==9)?1:0); } } } System.out.println("There are "+tens+" ways to roll a 10"); System.out.println("There are "+nines+" ways to roll a 9"); Which works just fine, and a brute force solution is what the teacher wanted us to do. However, it doesn't scale, and I am trying to find a way to make an algorithm that can calculate the number of ways to roll n dice to get a specific number. Therefore, I started generating the number of ways to get each sum with n dice. With 1 die, there is obviously 1 solution for each. I then calculated, through brute force, the combinations with 2 and 3 dice. These are for two: There are 1 ways to roll a 2 There are 2 ways to roll a 3 There are 3 ways to roll a 4 There are 4 ways to roll a 5 There are 5 ways to roll a 6 There are 6 ways to roll a 7 There are 5 ways to roll a 8 There are 4 ways to roll a 9 There are 3 ways to roll a 10 There are 2 ways to roll a 11 There are 1 ways to roll a 12 Which looks straightforward enough; it can be calculated with a simple linear absolute value function. But then things start getting trickier. With 3: There are 1 ways to roll a 3 There are 3 ways to roll a 4 There are 6 ways to roll a 5 There are 10 ways to roll a 6 There are 15 ways to roll a 7 There are 21 ways to roll a 8 There are 25 ways to roll a 9 There are 27 ways to roll a 10 There are 27 ways to roll a 11 There are 25 ways to roll a 12 There are 21 ways to roll a 13 There are 15 ways to roll a 14 There are 10 ways to roll a 15 There are 6 ways to roll a 16 There are 3 ways to roll a 17 There are 1 ways to roll a 18 So I look at that, and I think: Cool, Triangular numbers! However, then I notice those pesky 25s and 27s. So it's obviously not triangular numbers, but still some polynomial expansion, since it's symmetric. So I take to Google, and I come across this page that goes into some detail about how to do this with math. It is fairly easy(albeit long) to find this using repeated derivatives or expansion, but it would be much harder to program that for me. I didn't quite understand the second and third answers, since I have never encountered that notation or those concepts in my math studies before. Could someone please explain how I could write a program to do this, or explain the solutions given on that page, for my own understanding of combinatorics? EDIT: I'm looking for a mathematical way to solve this, that gives an exact theoretical number, not by simulating dice

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  • Row Number Transformation

    The Row Number Transformation calculates a row number for each row, and adds this as a new output column to the data flow. The column number is a sequential number, based on a seed value. Each row receives the next number in the sequence, based on the defined increment value. Develop seamlessly between Management Studio and Visual StudioSQL Connect is a Visual Studio add-in that makes it easy to keep your database and Visual Studio project in sync.

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  • Get special numbers from a random number generator

    - by Wikeno
    I have a random number generator: int32_t ksp_random_table[GENERATOR_DEG] = { -1726662223, 379960547, 1735697613, 1040273694, 1313901226, 1627687941, -179304937, -2073333483, 1780058412, -1989503057, -615974602, 344556628, 939512070, -1249116260, 1507946756, -812545463, 154635395, 1388815473, -1926676823, 525320961, -1009028674, 968117788, -123449607, 1284210865, 435012392, -2017506339, -911064859, -370259173, 1132637927, 1398500161, -205601318, }; int front_pointer=3, rear_pointer=0; int32_t ksp_rand() { int32_t result; ksp_random_table[ front_pointer ] += ksp_random_table[ rear_pointer ]; result = ( ksp_random_table[ front_pointer ] >> 1 ) & 0x7fffffff; front_pointer++, rear_pointer++; if (front_pointer >= GENERATOR_DEG) front_pointer = 0; if (rear_pointer >= GENERATOR_DEG) rear_pointer = 0; return result; } void ksp_srand(unsigned int seed) { int32_t i, dst=0, kc=GENERATOR_DEG, word, hi, lo; word = ksp_random_table[0] = (seed==0) ? 1 : seed; for (i = 1; i < kc; ++i) { hi = word / 127773, lo = word % 127773; word = 16807 * lo - 2836 * hi; if (word < 0) word += 2147483647; ksp_random_table[++dst] = word; } front_pointer=3, rear_pointer=0; kc *= 10; while (--kc >= 0) ksp_rand(); } I'd like know what type of pseudo random number generation algorithm this is. My guess is a multiple linear congruential generator. And is there a way of seeding this algorithm so that after 987721(1043*947) numbers it would return 15 either even-only, odd-only or alternating odd and even numbers? It is a part of an assignment for a long term competition and i've got no idea how to solve it. I don't want the final solution, I'd like to learn how to do it myself.

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  • How to Pregreplace {number}) with \n{number})

    - by streetparade
    How can i replace {number}) with \n{number}) Say i have something like this 1) test string testing new string. 2) that is also a new string no new line. 3) here also no new lines. The output should be something like this 1) test string testing new string. 2) that is also a new string no new line. 3) here also no new lines. How can i do that with a regex?

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  • Prepared statement help, Number of variables doesn't match number of parameters in prepared statement

    - by Sam Gabriel
    I'm getting this error : Number of variables doesn't match number of parameters in prepared statement every time I run this code: $dbh = new mysqli("localhost", "***", "***", "pics"); $stmt = $dbh->prepare("INSERT INTO comments (username, picture, comment) VALUES (?, ?, ?)"); $stmt->bind_Param('s', $username); $stmt->bind_Param('d', $picture); $stmt->bind_Param('s', $comment); $username=$_SESSION['username']; $picture=$_GET['id']; $comment=$_POST['comment']; $stmt->execute(); What's the problem?

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  • Code Metrics: Number of IL Instructions

    - by DigiMortal
    In my previous posting about code metrics I introduced how to measure LoC (Lines of Code) in .NET applications. Now let’s take a step further and let’s take a look how to measure compiled code. This way we can somehow have a picture about what compiler produces. In this posting I will introduce you code metric called number of IL instructions. NB! Number of IL instructions is not something you can use to measure productivity of your team. If you want to get better idea about the context of this metric and LoC then please read my first posting about LoC. What are IL instructions? When code written in some .NET Framework language is compiled then compiler produces assemblies that contain byte code. These assemblies are executed later by Common Language Runtime (CLR) that is code execution engine of .NET Framework. The byte code is called Intermediate Language (IL) – this is more common language than C# and VB.NET by example. You can use ILDasm tool to convert assemblies to IL assembler so you can read them. As IL instructions are building blocks of all .NET Framework binary code these instructions are smaller and highly general – we don’t want very rich low level language because it executes slower than more general language. For every method or property call in some .NET Framework language corresponds set of IL instructions. There is no 1:1 relationship between line in high level language and line in IL assembler. There are more IL instructions than lines in C# code by example. How much instructions there are? I have no common answer because it really depends on your code. Here you can see some metrics from my current community project that is developed on SharePoint Server 2007. As average I have about 7 IL instructions per line of code. This is not metric you should use, it is just illustrative example so you can see the differences between numbers of lines and IL instructions. Why should I measure the number of IL instructions? Just take a look at chart above. Compiler does something that you cannot see – it compiles your code to IL. This is not intuitive process because you usually cannot say what is exactly the end result. You know it at greater plain but you don’t know it exactly. Therefore we can expect some surprises and that’s why we should measure the number of IL instructions. By example, you may find better solution for some method in your source code. It looks nice, it works nice and everything seems to be okay. But on server under load your fix may be way slower than previous code. Although you minimized the number of lines of code it ended up with increasing the number of IL instructions. How to measure the number of IL instructions? My choice is NDepend because Visual Studio is not able to measure this metric. Steps to make are easy. Open your NDepend project or create new and add all your application assemblies to project (you can also add Visual Studio solution to project). Run project analysis and wait until it is done. You can see over-all stats form global summary window. This is the same window I used to read the LoC and the number of IL instructions metrics for my chart. Meanwhile I made some changes to my code (enabled advanced caching for events and event registrations module) and then I ran code analysis again to get results for this section of this posting. NDepend is also able to tell you exactly what parts of code have problematically much IL instructions. The code quality section of CQL Query Explorer shows you how much problems there are with members in analyzed code. If you click on the line Methods too big (NbILInstructions) you can see all the problematic members of classes in CQL Explorer shown in image on right. In my case if have 10 methods that are too big and two of them have horrible number of IL instructions – just take a look at first two methods in this TOP10. Also note the query box. NDepend has easy and SQL-like query language to query code analysis results. You can modify these queries if you like and also you can define your own ones if default set is not enough for you. What is good result? As you can see from query window then the number of IL instructions per member should have maximally 200 IL instructions. Of course, like always, the less instructions you have, the better performing code you have. I don’t mean here little differences but big ones. By example, take a look at my first method in warnings list. The number of IL instructions it has is huge. And believe me – this method looks awful. Conclusion The number of IL instructions is useful metric when optimizing your code. For analyzing code at general level to find out too long methods you can use the number of LoC metric because it is more intuitive for you and you can therefore handle the situation more easily. Also you can use NDepend as code metrics tool because it has a lot of metrics to offer.

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  • File system concepts (df command)

    - by mkab
    I'm finding it difficult to understand some stuffs about the df command. Suppose I type df and I have the following output Filesystem 1k-blocks Used Avail Capacity Mounted on /dev/da0s1 some number some number number percentage /win /dev/da0s2 some number some number number percentage /win/home /dev/da0s3a some number some number number percentage / devfs some number some number number percentage /dev /dev/da0s3g some number some number number percentage /local /dev/da0s3h some number some number -number 102% /reste /dev/da0s3d some number some number number percentage /tmp /dev/da1s3f some number some number number percentage /usr /dev/da1s3e some number some number number percentage /var /dev/da1s1a some number some number number percentage /public Are the answers to the following questions correct? How many physical drives do I have? Ans: 2. da0s1 and da1s1 How many physical partitions on each disk? Ans: 8 for da0s1 and 1 for da1s1 How many BSD partition on each physical partition Ans: Impossible to determine. We have to use the -T to determine its type How is it possible for the file system /dev/da0s3h filled at 102%? And where is this overflowed data written?Ans: I have no idea for this one Thanks.

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  • BIRT number to word as computed column

    - by Erwin
    Hi fellow programmer I want to ask how to add a computed column in BIRT that compute a number to its word representation? (ex. 100 to "one hundred") So in my data set I can have a column that holds the string I'm new at BIRT hopefully there's a pointer or two for me

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