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  • Partitioning data set in r based on multiple classes of observations

    - by Danny
    I'm trying to partition a data set that I have in R, 2/3 for training and 1/3 for testing. I have one classification variable, and seven numerical variables. Each observation is classified as either A, B, C, or D. For simplicity's sake, let's say that the classification variable, cl, is A for the first 100 observations, B for observations 101 to 200, C till 300, and D till 400. I'm trying to get a partition that has 2/3 of the observations for each of A, B, C, and D (as opposed to simply getting 2/3 of the observations for the entire data set since it will likely not have equal amounts of each classification). When I try to sample from a subset of the data, such as sample(subset(data, cl=='A')), the columns are reordered instead of the rows. To summarize, my goal is to have 67 random observations from each of A, B, C, and D as my training data, and store the remaining 33 observations for each of A, B, C, and D as testing data. I have found a very similar question to mine, but it did not factor in multiple variables. I feel silly asking this question because it seems so simple, but I'm stumped. Also, this is my first question on this site, so I apologize in advance for any faux pas on my part.

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  • [LaTeX] positions of page numbers, position of chapter headings, chapters AND Table of Contents, Ref

    - by kaikanmonaco
    I am writing my PhD thesis (120+ pages) in latex, the deadline is approaching and I am struggling with layout problems. I am using the documentstyle book. I am posting both problems in this one thread because I am not sure if the solution might be related to both problems or not. Problems are: 1.) The page numbers are mostly located on the top-right of each page (this is correct and where I want them to be). However, only on the first page of chapters and on the first page of what I call "special chapters", the page number is located bottom-centered. With "special chapters" I mean: List of Contents, List of Figures, List of Tables, References, Index. My university will not accept the thesis like this. The page number must ALWAYS be top-right one each page, even if the page is the first page of a chapter or the first page of something like the List of Contents. How can I fix this? 2.) On the first page of chapters and "special chapters" (List of Contents...), the chapter title is located far too low on the page. This is the standard layout of LaTeX with documentstyle book I think. However, the chapter title must start at the very top of the page! I.e. the same height as the normal text on the pages that follow. I mean the chapter title, not the header. I.e., if there is a chapter called "Chapter 1 Dynamics of foobar under mechanical stress" then that text has to start from the top the page, but right now it starts several centimeters below the top. How can I fix this? Have tried all kinds of things to no effect, I'd be very thankful for a solution! Thanks.

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  • Stop Visual Studio from appending numbers to the end of new controls

    - by techturtle
    I am wondering if there is any way to stop Visual Studio 2010 from appending a number to the end of the ID on new controls I create. For example, when I add a new TextBox, I would prefer that it do this: <asp:TextBox ID="TextBox" runat="server"> <asp:TextBox ID="TextBox" runat="server"> <asp:TextBox ID="TextBox" runat="server"> Instead of this: <asp:TextBox ID="TextBox1" runat="server"> <asp:TextBox ID="TextBox2" runat="server"> <asp:TextBox ID="TextBox3" runat="server"> It would make it easier to rename them appropriately, so I don't have to arrow/mouse over and delete the number each time. As I was writing this, the "Questions that may already have your answer" suggested this: How do I prevent Visual Studio from renaming my controls? which admittedly was the biggest part of my annoyance, but that appears to turn off putting in an ID="" field altogether, not just for pasted controls. It would still be helpful to turn off the numbering for new, non-pasted controls and have it not rename pasted ones as well. At the moment I'm working with ASP.NET, but it would be nice if it there was a way to do it for WinForms as well. Before anyone suggests it, I do know that allowing it to append the numbers prevents name conflicts should I not rename them appropriately. However, I would much rather have it fail to compile so I know to fix the issue now (if I forget to name something properly) rather than find random "TextBox1" items lying around in the code later on.

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  • Fastest way to clamp a real (fixed/floating point) value?

    - by Niklas
    Hi, Is there a more efficient way to clamp real numbers than using if statements or ternary operators? I want to do this both for doubles and for a 32-bit fixpoint implementation (16.16). I'm not asking for code that can handle both cases; they will be handled in separate functions. Obviously, I can do something like: double clampedA; double a = calculate(); clampedA = a > MY_MAX ? MY_MAX : a; clampedA = a < MY_MIN ? MY_MIN : a; or double a = calculate(); double clampedA = a; if(clampedA > MY_MAX) clampedA = MY_MAX; else if(clampedA < MY_MIN) clampedA = MY_MIN; The fixpoint version would use functions/macros for comparisons. This is done in a performance-critical part of the code, so I'm looking for an as efficient way to do it as possible (which I suspect would involve bit-manipulation) EDIT: It has to be standard/portable C, platform-specific functionality is not of any interest here. Also, MY_MIN and MY_MAX are the same type as the value I want clamped (doubles in the examples above).

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  • Generating different randoms valid for a day on different independent devices?

    - by Pentium10
    Let me describe the system. There are several mobile devices, each independent from each other, and they are generating content for the same record id. I want to avoid generating the same content for the same record on different devices, for this I though I would use a random and make it so too cluster the content pool based on these randoms. Suppose you have choices from 1 to 100. Day 1 Device#1 will choose for the record#33 between 1-10 Device#2 will choose for the record#33 between 40-50 Device#3 will choose for the record#33 between 50-60 Device#1 will choose for the record#55 between 40-50 Device#2 will choose for the record#55 between 1-10 Device#3 will choose for the record#55 between 10-20 Device#1 will choose for the record#11 between 1-10 Device#2 will choose for the record#22 between 1-10 Device#3 will choose for the record#99 between 1-10 Day 2 Device#1 will choose for the record#33 between 90-100 Device#2 will choose for the record#33 between 1-10 Device#3 will choose for the record#33 between 50-60 They don't have access to a central server. Data available for each of them: IMEI (unique per mobile) Date of today (same on all devices) Record id (same on all devices) What do you think, how is it possible? ps. tags can be edited

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  • Randomly sorting an array

    - by Cam
    Does there exist an algorithm which, given an ordered list of symbols {a1, a2, a3, ..., ak}, produces in O(n) time a new list of the same symbols in a random order without bias? "Without bias" means the probability that any symbol s will end up in some position p in the list is 1/k. Assume it is possible to generate a non-biased integer from 1-k inclusive in O(1) time. Also assume that O(1) element access/mutation is possible, and that it is possible to create a new list of size k in O(k) time. In particular, I would be interested in a 'generative' algorithm. That is, I would be interested in an algorithm that has O(1) initial overhead, and then produces a new element for each slot in the list, taking O(1) time per slot. If no solution exists to the problem as described, I would still like to know about solutions that do not meet my constraints in one or more of the following ways (and/or in other ways if necessary): the time complexity is worse than O(n). the algorithm is biased with regards to the final positions of the symbols. the algorithm is not generative. I should add that this problem appears to be the same as the problem of randomly sorting the integers from 1-k, since we can sort the list of integers from 1-k and then for each integer i in the new list, we can produce the symbol ai.

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  • How to separate sets of numbers onto separate lines

    - by Fred
    About the script: The script below will create 300 sets of random characters. What is presently happening, is that it creates them but shows them all on one line, in one big chunk. With all the searching and testing I've done to try and achieve this, I have had no success. I would like to know which code and where to put it, so that each SET (300) of 15 characters long, will show and be saved to file. Here is my script: <?php function GetID($x){ $characters = array_merge(range('A','Z'),range('a','z'),range(2,9)); shuffle($characters); for($x=0;$x<=299;$x++){ } for (; strlen($ReqID)<$x;){ $ReqID .= $characters[mt_rand(0, count($characters))]; } return $ReqID; } $ReqID .= GetID(5); $ReqID .= "-"; $ReqID .= GetID(5); $ReqID .= "-"; $ReqID .= GetID(5); echo $ReqID; $fh = fopen("file.txt","a+"); fwrite($fh, ("$ReqID")."\n"); fclose($fh); ?>

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  • Strange numbers in java socket output

    - by user293163
    I have small test app: Socket socket = new Socket("jeck.ru", 80); PrintWriter pw = new PrintWriter(socket.getOutputStream(), false); pw.println("GET /ip/ HTTP/1.1"); pw.println("Host: jeck.ru"); pw.println(); pw.flush(); BufferedReader rd = new BufferedReader(new InputStreamReader(socket.getInputStream())); String str; while ((str = rd.readLine()) != null) { System.out.println(str); } It`s output: HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server: Apache Cache-Control: max-age=0 Expires: Sat, 13 Mar 2010 22:06:51 GMT 123 <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>??? IP</title> </head> <body> <div style='text-align: center; font: 32pt Verdana;margin-top: 300px'> ??? IP &#151; 94.103.87.153 </div> </body> </html> 0 Whence these numbers (123 an 0) takes?

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  • Querying XML using node numbers

    - by CP
    Okay, so I'm writing a utility that compares 2 XML documents using Microsoft's XML diff patch tool. The result looks something like this: <?xml version="1.0" encoding="utf-16"?><xd:xmldiff version="1.0" srcDocHash="10728157883908851288" options="IgnoreChildOrder IgnoreComments IgnoreWhitespace " fragments="yes" xmlns:xd="http://schemas.microsoft.com/xmltools/2002/xmldiff"><xd:node match="1"><xd:node match="1"><xd:node match="1"><xd:node match="2"><xd:node match="1"><xd:node match="1"><xd:node match="2"><xd:change match="1">testi22n2123</xd:change></xd:node></xd:node><xd:add match="/1/1/1/2/1/8" opid="1" /><xd:node match="7"><xd:node match="1"><xd:change match="1">31</xd:change></xd:node><xd:node match="2"><xd:change match="1">test2ing</xd:change></xd:node></xd:node><xd:remove match="8" opid="1" /></xd:node></xd:node></xd:node></xd:node></xd:node><xd:descriptor opid="1" type="move" /></xd:xmldiff> What I'm trying to do is go back into the source document and get the source data that represents the difference. I initially tried creating an Xpath query, but as I understand it now this XmlDiff thing works off the DOM... which seems like the dinosaur of XML objects these days. What's the best way to get at the node in the source XML by using the numbers provided in the diff result?

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  • Numbers localization

    - by Reza
    How can I set the variant of Arabic numeral without changing number characters ? Eastern Arabic ? ? ? ? ? ? ? ? ? ? Persian variant ? ? ? ? ? ? ? ? ? ? Western Arabic 0 1 2 3 4 5 6 7 8 9 here is a sample code: <!DOCTYPE html> <html> <meta charset="utf-8"> <head> <title></title> </head> <body> <div lang="fa">123456789</div> <div lang="ar">123456789</div> <div lang="en">123456789</div> </body> </html> Also note that in Windows text boxes (e.g. Run) numbers are displayed correctly according to surrounding text languages.

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  • Storing large numbers of varying size objects on disk

    - by Foredecker
    I need to develop a system for storing large numbers (10's to 100's of thousands) of objects. Each object is email-like - there is a main text body, and several ancillary text fields of limited size. A body will be from a few bytes, to several KB in size. Each item will have a single unique ID (probably a GUID) that identifies it. The store will only be written to when an object is added to it. It will be read often. Deletions will be rare. The data is almost all human readable text so it will be readily compressible. A system that lets me issue the I/Os and mange the memory and caching would be ideal. I'm going to keep the indexes in memory, using it to map indexes to the single (and primary) key for the objects. Once I have the key, then I'll load it from disk, or the cache. The data management system needs to be part of my application - I do not want to depend on OS services. Or separately installed packages. Native (C++) would be best, but a manged (C#) thing would be ok. I believe that a database is an obvious choice, but this needs to be super-fast for look up and loading into memory of an object. I am not experienced with data base tech and I'm concerned that general relational systems will not handle all this variable sized data efficiently. (Note, this has nothing to do with my job - its a personal project.) In your experience, what are the viable alternatives to a traditional relational DB? Or would a DB work well for this?

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  • How do I read hex numbers into an unsigned int in C [Solved]

    - by sil3nt
    I'm wanting to read hex numbers from a text file into an unsigned integer so that I can execute Machine instructions. It's just a simulation type thing that looks inside the text file and according to the values and its corresponding instruction outputs the new values in the registers. For example, the instructions would be: 1RXY - Save register R with value in memory address XY 2RXY - Save register R with value XY BRXY - Jump to register R if xy is this and that etc.. ARXY - AND register R with value at memory address XY The text file contains something like this each in a new line. (in hexidecimal) 120F B007 290B My problem is copying each individual instruction into an unsigned integer...how do I do this? #include <stdio.h> int main(){ FILE *f; unsigned int num[80]; f=fopen("values.txt","r"); if (f==NULL){ printf("file doesnt exist?!"); } int i=0; while (fscanf(f,"%x",num[i]) != EOF){ fscanf(f,"%x",num[i]); i++; } fclose(f); printf("%x",num[0]); }

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  • regex numeric data processing: match a series of numbers greater than X

    - by Mu Mind
    Say I have some data like this: number_stream = [0,0,0,7,8,0,0,2,5,6,10,11,10,13,5,0,1,0,...] I want to process it looking for "bumps" that meet a certain pattern. Imagine I have my own customized regex language for working on numbers, where [[ =5 ]] represents any number = 5. I want to capture this case: ([[ >=5 ]]{3,})[[ <3 ]]{2,} In other words, I want to begin capturing any time I look ahead and see 3 or more values = 5 in a row, and stop capturing any time I look ahead and see 2+ values < 3. So my output should be: >>> stream_processor.process(number_stream) [[5,6,10,11,10,13,5],...] Note that the first 7,8,... is ignored because it's not long enough, and that the capture ends before the 0,1,0.... I'd also like a stream_processor object I can incrementally pass more data into in subsequent process calls, and return captured chunks as they're completed. I've written some code to do it, but it was hideous and state-machiney, and I can't help feeling like I'm missing something obvious. Any ideas to do this cleanly?

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  • Given a vector of maximum 10 000 natural and distinct numbers, find 4 numbers(a, b, c, d) such that

    - by king_kong
    Hi, I solved this problem by following a straightforward but not optimal algorithm. I sorted the vector in descending order and after that substracted numbers from max to min to see if I get a + b + c = d. Notice that I haven't used anywhere the fact that elements are natural, distinct and 10 000 at most. I suppose these details are the key. Does anyone here have a hint over an optimal way of solving this? Thank you in advance! Later Edit: My idea goes like this: '<<quicksort in descending order>>' for i:=0 to count { // after sorting, loop through the array int d := v[i]; for j:=i+1 to count { int dif1 := d - v[j]; int a := v[j]; for k:=j+1 to count { if (v[k] > dif1) continue; int dif2 := dif1 - v[k]; b := v[k]; for l:=k+1 to count { if (dif2 = v[l]) { c := dif2; return {a, b, c, d} } } } } } What do you think?(sorry for the bad indentation)

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  • Using regex to fix phone numbers in a CSV with PHP

    - by Hurpe
    My new phone does not recognize a phone number unless it's area code matches the incoming call. Since I live in Idaho where an area code is not needed for in-state calls, many of my contacts were saved without an area code. Since I have thousands of contacts stored in my phone, it would not be practical to manually update them. I decided to write the following PHP script to handle the problem. It seems to work well, except that I'm finding duplicate area codes at the beginning of random contacts. <?php //the script can take a while to complete set_time_limit(200); function validate_area_code($number) { //digits are taken one by one out of $number, and insert in to $numString $numString = ""; for ($i = 0; $i < strlen($number); $i++) { $curr = substr($number,$i,1); //only copy from $number to $numString when the character is numeric if (is_numeric($curr)) { $numString = $numString . $curr; } } //add area code "208" to the beginning of any phone number of length 7 if (strlen($numString) == 7) { return "208" . $numString; //remove country code (none of the contacts are outside the U.S.) } else if (strlen($numString) == 11) { return preg_replace("/^1/","",$numString); } else { return $numString; } } //matches any phone number in the csv $pattern = "/((1? ?\(?[2-9]\d\d\)? *)? ?\d\d\d-?\d\d\d\d)/"; $csv = file_get_contents("contacts2.CSV"); preg_match_all($pattern,$csv,$matches); foreach ($matches[0] as $key1 => $value) { /*create a pattern that matches the specific phone number by adding slashes before possible special characters*/ $pattern = preg_replace("/\(|\)|\-/","\\\\$0",$value); //create the replacement phone number $replacement = validate_area_code($value); //add delimeters $pattern = "/" . $pattern . "/"; $csv = preg_replace($pattern,$replacement,$csv); } echo $csv; ?> Is there a better approach to modifying the csv? Also, is there a way to minimize the number of passes over the csv? In the script above, preg_replace is called thousands of times on a very large String.

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  • Classifying captured data in unknown format?

    - by monch1962
    I've got a large set of captured data (potentially hundreds of thousands of records), and I need to be able to break it down so I can both classify it and also produce "typical" data myself. Let me explain further... If I have the following strings of data: 132T339G1P112S 164T897F5A498S 144T989B9B223T 155T928X9Z554T ... you might start to infer the following: possibly all strings are 14 characters long the 4th, 8th, 10th and 14th characters may always be alphas, while the rest are numeric the first character may always be a '1' the 4th character may always be the letter 'T' the 14th character may be limited to only being 'S' or 'T' and so on... As you get more and more samples of real data, some of these "rules" might disappear; if you see a 15 character long string, then you have evidence that the 1st "rule" is incorrect. However, given a sufficiently large sample of strings that are exactly 14 characters long, you can start to assume that "all strings are 14 characters long" and assign a numeric figure to your degree of confidence (with an appropriate set of assumptions around the fact that you're seeing a suitably random set of all possible captured data). As you can probably tell, a human can do a lot of this classification by eye, but I'm not aware of libraries or algorithms that would allow a computer to do it. Given a set of captured data (significantly more complex than the above...), are there libraries that I can apply in my code to do this sort of classification for me, that will identify "rules" with a given degree of confidence? As a next step, I need to be able to take those rules, and use them to create my own data that conforms to these rules. I assume this is a significantly easier step than the classification, but I've never had to perform a task like this before so I'm really not sure how complex it is. At a guess, Python or Java (or possibly Perl or R) are possibly the "common" languages most likely to have these sorts of libraries, and maybe some of the bioinformatic libraries do this sort of thing. I really don't care which language I have to use; I need to solve the problem in whatever way I can. Any sort of pointer to information would be very useful. As you can probably tell, I'm struggling to describe this problem clearly, and there may be a set of appropriate keywords I can plug into Google that will point me towards the solution. Thanks in advance

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  • Best Practices / Patterns for Enterprise Protection/Remediation of SSNs (Social Security Numbers)

    - by Erik Neu
    I am interested in hearing about enterprise solutions for SSN handling. (I looked pretty hard for any pre-existing post on SO, including reviewing the terriffic SO automated "Related Questions" list, and did not find anything, so hopefully this is not a repeat.) First, I think it is important to enumerate the reasons systems/databases use SSNs: (note—these are reasons for de facto current state—I understand that many of them are not good reasons) Required for Interaction with External Entities. This is the most valid case—where external entities your system interfaces with require an SSN. This would typically be government, tax and financial. SSN is used to ensure system-wide uniqueness. SSN has become the default foreign key used internally within the enterprise, to perform cross-system joins. SSN is used for user authentication (e.g., log-on) The enterprise solution that seems optimum to me is to create a single SSN repository that is accessed by all applications needing to look up SSN info. This repository substitutes a globally unique, random 9-digit number (ASN) for the true SSN. I see many benefits to this approach. First of all, it is obviously highly backwards-compatible—all your systems "just" have to go through a major, synchronized, one-time data-cleansing exercise, where they replace the real SSN with the alternate ASN. Also, it is centralized, so it minimizes the scope for inspection and compliance. (Obviously, as a negative, it also creates a single point of failure.) This approach would solve issues 2 and 3, without ever requiring lookups to get the real SSN. For issue #1, authorized systems could provide an ASN, and be returned the real SSN. This would of course be done over secure connections, and the requesting systems would never persist the full SSN. Also, if the requesting system only needs the last 4 digits of the SSN, then that is all that would ever be passed. Issue #4 could be handled the same way as issue #1, though obviously the best thing would be to move away from having users supply an SSN for log-on. There are a couple of papers on this: UC Berkely: http://bit.ly/bdZPjQ Oracle Vault: bit.ly/cikbi1

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  • Checking if an int is prime more efficiently

    - by SipSop
    I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

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  • How to use a separate class to validate credit card numbers in C#

    - by EvanRyan
    I have set up a class to validate credit card numbers. The credit card type and number are selected on a form in a separate class. I'm trying to figure out how to get the credit card type and number that are selected in the other class (frmPayment) in to my credit card class algorithm: public enum CardType { MasterCard, Visa, AmericanExpress } public sealed class CardValidator { public static string SelectedCardType { get; private set; } public static string CardNumber { get; private set; } private CardValidator(string selectedCardType, string cardNumber) { SelectedCardType = selectedCardType; CardNumber = cardNumber; } public static bool Validate(CardType cardType, string cardNumber) { byte[] number = new byte[16]; int length = 0; for (int i = 0; i < cardNumber.Length; i++) { if (char.IsDigit(cardNumber, i)) { if (length == 16) return false; number[length++] = byte.Parse(cardNumber[i]); //not working. find different way to parse } } switch(cardType) { case CardType.MasterCard: if(length != 16) return false; if(number[0] != 5 || number[1] == 0 || number[1] > 5) return false; break; case CardType.Visa: if(length != 16 & length != 13) return false; if(number[0] != 4) return false; break; case CardType.AmericanExpress: if(length != 15) return false; if(number[0] != 3 || (number[1] != 4 & number[1] != 7)) return false; break; } // Use Luhn Algorithm to validate int sum = 0; for(int i = length - 1; i >= 0; i--) { if(i % 2 == length % 2) { int n = number[i] * 2; sum += (n / 10) + (n % 10); } else sum += number[i]; } return (sum % 10 == 0); } }

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  • Template problems: No matching function for call

    - by Nick Sweet
    I'm trying to create a template class, and when I define a non-member template function, I get the "No matching function for call to randvec()" error. I have a template class defined as: template <class T> class Vector { T x, y, z; public: //constructors Vector(); Vector(const T& x, const T& y, const T& z); Vector(const Vector& u); //accessors T getx() const; T gety() const; T getz() const; //mutators void setx(const T& x); void sety(const T& y); void setz(const T& z); //operations void operator-(); Vector plus(const Vector& v); Vector minus(const Vector& v); Vector cross(const Vector& v); T dot(const Vector& v); void times(const T& s); T length() const; //Vector<T>& randvec(); //operators Vector& operator=(const Vector& rhs); friend std::ostream& operator<< <T>(std::ostream&, const Vector<T>&); }; and the function in question, which I've defined after all those functions above, is: //random Vector template <class T> Vector<double>& randvec() { const int min=-10, max=10; Vector<double>* r = new Vector<double>; int randx, randy, randz, temp; const int bucket_size = RAND_MAX/(max-min +1); temp = rand(); //voodoo hackery do randx = (rand()/bucket_size)+min; while (randx < min || randx > max); r->setx(randx); do randy = (rand()/bucket_size)+min; while (randy < min || randy > max); r->sety(randy); do randz = (rand()/bucket_size)+min; while (randz < min || randz > max); r->setz(randz); return *r; } Yet, every time I call it in my main function using a line like: Vector<double> a(randvec()); I get that error. However, if I remove the template and define it using 'double' instead of 'T', the call to randvec() works perfectly. Why doesn't it recognize randvec()? P.S. Don't mind the bit labeled voodoo hackery - this is just a cheap hack so that I can get around another problem I encountered.

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  • Is it possible to shuffle a 2D matrix while preserving row AND column frequencies?

    - by j_random_hacker
    Suppose I have a 2D array like the following: GACTG AGATA TCCGA Each array element is taken from a small finite set (in my case, DNA nucleotides -- {A, C, G, T}). I would like to randomly shuffle this array somehow while preserving both row and column nucleotide frequencies. Is this possible? Can it be done efficiently? [EDIT]: By this I mean I want to produce a new matrix where each row has the same number of As, Cs, Gs and Ts as the corresponding row of the original matrix, and where each column has the same number of As, Cs, Gs and Ts as the corresponding column of the original matrix. Permuting the rows or columns of the original matrix will not achieve this in general. (E.g. for the example above, the top row has 2 Gs, and 1 each of A, C and T; if this row was swapped with row 2, the top row in the resulting matrix would have 3 As, 1 G and 1 T.) It's simple enough to preserve just column frequencies by shuffling a column at a time, and likewise for rows. But doing this will in general alter the frequencies of the other kind. My thoughts so far: If it's possible to pick 2 rows and 2 columns so that the 4 elements at the corners of this rectangle have the pattern XY YX for some pair of distinct elements X and Y, then replacing these 4 elements with YX XY will maintain both row and column frequencies. In the example at the top, this can be done for (at least) rows 1 and 2 and columns 2 and 5 (whose corners give the 2x2 matrix AG;GA), and for rows 1 and 3 and columns 1 and 4 (whose corners give GT;TG). Clearly this could be repeated a number of times to produce some level of randomisation. Generalising a bit, any "subrectangle" induced by a subset of rows and a subset of columns, in which the frequencies of all rows are the same and the frequencies of all columns are the same, can have both its rows and columns permuted to produce a valid complete rectangle. (Of these, only those subrectangles in which at least 1 element is changed are actually interesting.) Big questions: Are all valid complete matrices reachable by a series of such "subrectangle rearrangements"? I suspect the answer is yes. Are all valid subrectangle rearrangements decomposable into a series of 2x2 swaps? I suspect the answer is no, but I hope it's yes, since that would seem to make it easier to come up with an efficient algorithm. Can some or all of the valid rearrangements be computed efficiently? This question addresses a special case in which the set of possible elements is {0, 1}. The solutions people have come up with there are similar to what I have come up with myself, and are probably usable, but not ideal as they require an arbitrary amount of backtracking to work correctly. Also I'm concerned that only 2x2 swaps are considered. Finally, I would ideally like a solution that can be proven to select a matrix uniformly at random from the set of all matrices having identical row frequencies and column frequencies to the original. I know, I'm asking for a lot :)

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  • Java unit test coverage numbers do not match.

    - by Dan
    Below is a class I have written in a web application I am building using Java Google App Engine. I have written Unit Tests using TestNG and all the tests pass. I then run EclEmma in Eclipse to see the test coverage on my code. All the functions show 100% coverage but the file as a whole is showing about 27% coverage. Where is the 73% uncovered code coming from? Can anyone help me understand how EclEmma works and why I am getting the discrepancy in numbers? package com.skaxo.sports.models; import javax.jdo.annotations.IdGeneratorStrategy; import javax.jdo.annotations.IdentityType; import javax.jdo.annotations.PersistenceCapable; import javax.jdo.annotations.Persistent; import javax.jdo.annotations.PrimaryKey; @PersistenceCapable(identityType= IdentityType.APPLICATION) public class Account { @PrimaryKey @Persistent(valueStrategy=IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String userId; @Persistent private String firstName; @Persistent private String lastName; @Persistent private String email; @Persistent private boolean termsOfService; @Persistent private boolean systemEmails; public Account() {} public Account(String firstName, String lastName, String email) { super(); this.firstName = firstName; this.lastName = lastName; this.email = email; } public Account(String userId) { super(); this.userId = userId; } public void setId(Long id) { this.id = id; } public Long getId() { return id; } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public boolean acceptedTermsOfService() { return termsOfService; } public void setTermsOfService(boolean termsOfService) { this.termsOfService = termsOfService; } public boolean acceptedSystemEmails() { return systemEmails; } public void setSystemEmails(boolean systemEmails) { this.systemEmails = systemEmails; } } Below is the test code for the above class. package com.skaxo.sports.models; import static org.testng.Assert.assertEquals; import static org.testng.Assert.assertNotNull; import static org.testng.Assert.assertTrue; import static org.testng.Assert.assertFalse; import org.testng.annotations.BeforeTest; import org.testng.annotations.Test; public class AccountTest { @Test public void testId() { Account a = new Account(); a.setId(1L); assertEquals((Long) 1L, a.getId(), "ID"); a.setId(3L); assertNotNull(a.getId(), "The ID is set to null."); } @Test public void testUserId() { Account a = new Account(); a.setUserId("123456ABC"); assertEquals(a.getUserId(), "123456ABC", "User ID incorrect."); a = new Account("123456ABC"); assertEquals(a.getUserId(), "123456ABC", "User ID incorrect."); } @Test public void testFirstName() { Account a = new Account("Test", "User", "[email protected]"); assertEquals(a.getFirstName(), "Test", "User first name not equal to 'Test'."); a.setFirstName("John"); assertEquals(a.getFirstName(), "John", "User first name not equal to 'John'."); } @Test public void testLastName() { Account a = new Account("Test", "User", "[email protected]"); assertEquals(a.getLastName(), "User", "User last name not equal to 'User'."); a.setLastName("Doe"); assertEquals(a.getLastName(), "Doe", "User last name not equal to 'Doe'."); } @Test public void testEmail() { Account a = new Account("Test", "User", "[email protected]"); assertEquals(a.getEmail(), "[email protected]", "User email not equal to '[email protected]'."); a.setEmail("[email protected]"); assertEquals(a.getEmail(), "[email protected]", "User email not equal to '[email protected]'."); } @Test public void testAcceptedTermsOfService() { Account a = new Account(); a.setTermsOfService(true); assertTrue(a.acceptedTermsOfService(), "Accepted Terms of Service not true."); a.setTermsOfService(false); assertFalse(a.acceptedTermsOfService(), "Accepted Terms of Service not false."); } @Test public void testAcceptedSystemEmails() { Account a = new Account(); a.setSystemEmails(true); assertTrue(a.acceptedSystemEmails(), "System Emails is not true."); a.setSystemEmails(false); assertFalse(a.acceptedSystemEmails(), "System Emails is not false."); } }

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  • Can first descendent be selected directly?

    - by Ben Huh
    I am currently using find() and first() method to select the first descendent element from each of the <div> elements that contains the parent class. But I find this quite cumbersome since find() method would produce a set of matched elements before the first element is being picked. The following is the skeleton of my code: HTML <div class=parent> <ul> <li>random characters</li> <li>random characters</li> <li>random characters</li> <li>random characters</li> </ul> </div> <div class=parent> <ul> <li>random characters</li> <li>random characters</li> <li>random characters</li> <li>random characters</li> </ul> </div> <div class=non-parent> <ul> <li>random characters</li> <li>random characters</li> <li>random characters</li> <li>random characters</li> </ul> </div> <div class=parent> <ul> <li>random characters</li> <li>random characters</li> <li>random characters</li> <li>random characters</li> </ul> </div> // .....the list continues Javascript $('.parent').each(function() { $(this).find('ul li').first().css('color', 'red'); // do other stuff within each loop }); I have seen people using $(".parent li:first") selector. But, because I am doing it in a loop, I am not sure how or whether if this could be done and would like some advice. Thanks.

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  • Numbers not adding up? (What am I not understanding here?) [closed]

    - by Milo
    I have the following output: Short version: The last numbers on the S= lines increase by H and SHOULD theoretically be linearly decreasing, ex: -285,-290,-295...but the fourth one jumps to -252. Yet, every other number is linearly increasing. Why is that and how could I fix that? To explain the numbers, it comes from slider value changed. I have a slider whose value is used to generate the float on the next line. Everything should be growing linearly here. This value is used to determine the size of a flow layout and it is also used in conjunction with a scrollbar. But basically I have a background for the flow layout and that number is the start location for rendering it. The numbers should linearly change to create a smooth transition but when that one jumps, it looks weird on screen and I dont understand why the numbers are jumping every X slider value changes. Mathematically what could be causing this? Here is the code for rendering the background and the function that is called when value changes: void LobbyTableManager::renderBG( GraphicsContext* g, agui::Rectangle& absRect, agui::Rectangle& childRect ) { float scale = 0.35f; int w = m_bgSprite->getWidth() * getTableScale() * scale; int h = m_bgSprite->getHeight() * getTableScale() * scale; int numX = ceil(absRect.getWidth() / (float)w) + 2; int numY = ceil(absRect.getHeight() / (float)h) + 2; int startY = childRect.getY(); int numAttempts = 0; while(startY + h < absRect.getY() && numAttempts < 1000) { startY += h; if(moo) { std::cout << startY << ","; } numAttempts++; } g->holdDrawing(); for(int i = 0; i < numX; ++i) { for(int j = 0; j < numY; ++j) { g->drawScaledSprite(m_bgSprite,0,0,m_bgSprite->getWidth(),m_bgSprite->getHeight(), absRect.getX() + (i * w) + (offsetX),absRect.getY() + (j * h) + startY,w,h,0); } } g->unholdDrawing(); g->setClippingRect(cx,cy,cw,ch); } void LobbyTableManager::setTableScale( float scale ) { scale += 0.3f; scale *= 2.0f; float scrollRel = m_vScroll->getRelativeValue(); setScale(scale); rescaleTables(); resizeFlow(); updateScrollBars(); float newVal = scrollRel * m_vScroll->getMaxValue(); m_vScroll->setValue(newVal); } void LobbyTableManager::valueChanged( agui::VScrollBar* source,int val ) { m_flow->setLocation(0,-val); } Any insight on mathematically why the anomaly might happen every Nth time would be helpful. I just dont understand why if every number linearly increates it jumps from -295 to -252! Thanks

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  • Dedicated Servers: Is one better then two for LAMP pseudo HA setup? [closed]

    - by bikedorkseattle
    Possible Duplicate: How to find web hosting that meets my requirements? I know there are zillions of commentary about hosting out there, but I haven't read much about this. Our current well known host is having too many problems, the hardware we are on it subpar, and I'm ready to leave. A day of downtime can cost as much as our monthly hosting bill. A month of bad performance is just killing us right now, user and google wise. I'm wondering about running two dedicated boxes for LAMP, one running as the primary Nginx/Apache (proxy pass), and the other as the MySQL box. Running a single box scares the bejesus out of me because who knows how long it will take anyone to fix a raid card or whatever. The idea is to set this up using some sort of failover system using pacemaker and heartbeat. If one server goes down the other can take over for the other running both web and db. There are some good articles over at Linode about this. I have a few DBs that are 1GB+ and would like to load them into memory. Because of this, I'm shying away from a Linode HA setup because for the price I could do it with two dedicated like I described. Am I mad or an idiot? What are people out there doing for pseodu high availability good performance setups under $400/month? I'm a webmaster; I do a lot of things none of it that well :)

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