Search Results

Search found 3211 results on 129 pages for 'mpi beginner'.

Page 42/129 | < Previous Page | 38 39 40 41 42 43 44 45 46 47 48 49  | Next Page >

  • More ruby-like solution to this problem?

    - by RaouL
    I am learning ruby and practicing it by solving problems from Project Euler. This is my solution for problem 12. # Project Euler problem: 12 # What is the value of the first triangle number to have over five hundred divisors? require 'prime' triangle_number = ->(num){ (num *(num + 1)) / 2 } factor_count = ->(num) do prime_fac = Prime.prime_division(num) exponents = prime_fac.collect { |item| item.last + 1 } fac_count = exponents.inject(:*) end n = 2 loop do tn = triangle_number.(n) if factor_count.(tn) >= 500 puts tn break end n += 1 end Any improvements that can be made to this piece of code?

    Read the article

  • Form to sort an index in rails

    - by shmichael
    I'm a newcomer to Rails. I want to build a simple form that determines the sort order of a list. I've implemented a form in the likes of - <%= radio_button_tag :sort, "rating" %> <%= label_tag :sort_rating, "order by rating" %> <%= radio_button_tag :sort, "name" %> <%= label_tag :sort_name, "order by name" %> And now I am unsure how to implement the sort at the controller/model level. The aspects I am puzzled about are: Where should the sort be performed How could the sort parameter be persisted How could the code be reused Right now, I can't even get the selected sort method to remain selected after a submit. I would most appreciate any guidance or reference to an example.

    Read the article

  • Global and local variables in my script

    - by Acorn
    I'm starting out learning javascript, and tried to write a little script that would make a grid of divs on a page. Here's the script: var tileWidth=50; var tileHeight=100; var leftPos=10; var topPos=10; var columns=10; var rows=10; var spacing=5; $('document').ready(function() { placeTiles(); }); function makeRow() { for (var i=0; i<columns; i++) { $('#canvas').append('<div class="tile" style="left:' + leftPos + 'px;top:' + topPos + 'px;"></div>'); var leftPos = leftPos + tileWidth + spacing; } } function placeTiles() { for (var i=0; i<rows; i++) { makeRow(); var topPos = topPos + tileHeight + spacing; } } At the moment, 100 <div>s get created, all with a top position of 10px and a left position of undefined (for the first <div> in the row) or NaN. What should I be doing differently? Why can't makerow() see my global leftPos variable (and all the other variables for that matter)? Thanks.

    Read the article

  • Is there a difference here?

    - by HotHead
    Please consider following code: 1. uint16 a = 0x0001; if(a < 0x0002) { // do something } 2. uint16 a = 0x0001; if(a < uint16(0x0002)) { // do something } 3. uint16 a = 0x0001; if(a < static_cast<uint16>(0x0002)) { // do something } 4. uint16 a = 0x0001; uint16 b = 0x0002; if(a < b) { // do something } What compiler does in backgorund and what is the best (and correct) way to do above testing? p.s. sorry, but I couldn't find the better title :) Thank you in advance!

    Read the article

  • Efficient way in Python to add an element to a comma-separated string

    - by ensnare
    I'm looking for the most efficient way to add an element to a comma-separated string while maintaining alphabetical order for the words: For example: string = 'Apples, Bananas, Grapes, Oranges' addition = 'Cherries' result = 'Apples, Bananas, Cherries, Grapes, Oranges' Also, a way to do this but while maintaining IDs: string = '1:Apples, 4:Bananas, 6:Grapes, 23:Oranges' addition = '62:Cherries' result = '1:Apples, 4:Bananas, 62:Cherries, 6:Grapes, 23:Oranges' Sample code is greatly appreciated. Thank you so much.

    Read the article

  • Loading attribute in XPATH, problem

    - by Nguyen Quoc Hung
    I've got a question about loading attribute in XPATH. I write short XML code to test: <?xml version="1.0" encoding="iso-8859-1"?> <?xml-stylesheet type="text/xsl" href="testDate.xsl"?> <element attribute="1/1/2100"> Hung </element> My XSL code: <?xml version="1.0" encoding="iso-8859-1"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <!--Handle the document: set up HTML page--> <xsl:template match="/"> <html> <head> </head> <body> This is a test <xsl:value-of select="element@attribute"/> </body> </html> </xsl:template> </xsl:stylesheet> Why it produces an error when loading the stylesheet? Would you please help me explain this? Thank you

    Read the article

  • Parallel Assignment operator in Ruby

    - by Bragaadeesh
    Hi, I was going through an example from Programming in Ruby book. This is that example def fib_up_to(max) i1, i2 = 1, 1 # parallel assignment (i1 = 1 and i2 = 1) while i1 <= max yield i1 i1, i2 = i2, i1+i2 end end fib_up_to(100) {|f| print f, " " } The above program simply prints the fibonacci numbers upto 100. Thats fine. My question here is when i replace the parallel assignment with something like this, i1 = i2 i2 = i1+i2 I am not getting the desired output. My question here is, is it advisable to use parallel assignments? (I come from Java background and it feels really wierd to see this type of assignment) One more doubt is : Is parallel assignment an operator?? Thanks

    Read the article

  • split twice in the same expression?

    - by UcanDoIt
    Imagine I have the following: inFile = "/adda/adas/sdas/hello.txt" # that instruction give me hello.txt Name = inFile.name.split("/") [-1] # that one give me the name I want - just hello Name1 = Name.split(".") [0] Is there any chance to simplify that doing the same job in just one expression?

    Read the article

  • What makes you want to learn Common Lisp? What do you want from it?

    - by JasonFruit
    I'm working on a toolkit (sort of a live-CD Lisp-in-a-Box) for people new to Common Lisp, and I want to make sure it is broadly satisfying. What is attractive to you about Lisp? What do/did/would you need to get you started and keep you interested? What I have so far: SBCL 10.22, Emacs 22.3, SLIME, and LTK bundled together and configured on a Linux live-CD that boots entirely to RAM. I've now released the result of this; it is available at the Thnake website.

    Read the article

  • Should I add try/catch around when casting on an attribute of JSP implicit object?

    - by Michael Mao
    Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

    Read the article

  • C# Proxy, what is the best way to do this?

    - by Kin
    I'm writing a proxy using .NET and C#. It has a couple of functions that it needs to fulfill. I haven't done much Socket programming, and I am not sure the best way to go about it. Should I use Synchronous Sockets, Asynchronous sockets? Please help! It must... Accept Connections from the client on two different ports, and be able to receive data on both ports at the same time. When a connection is made on a port, it must immediately connect to the server, and start sending data as it receives it from the client to the server. Packets must be forwarded in the order they are received, exactly as they were received. It needs to be as low latency as possible. I don't need the ability for multiple clients to use the proxy, but it would be a nice feature if its easy to implement.

    Read the article

  • C++: Templates for static functions?

    - by Rosarch
    I have a static Utils class. I want certain methods to be templated, but not the entire class. How do I do this? This fails: #pragma once #include <string> using std::string; class Utils { private: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); public: static void PrintLine(const string& line, int tabLevel = 0); static string getTabs(int tabLevel); template<class InputIterator, class Predicate> static set<char> Utils::findAll_if(InputIterator begin, InputIterator end, Predicate pred); }; Error: utils.h(10): error C2143: syntax error : missing ';' before '<' utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C2238: unexpected token(s) preceding ';' utils.h(10): error C2988: unrecognizable template declaration/definition utils.h(10): error C2059: syntax error : '<' What am I doing wrong? What is the correct syntax for this? Incidentally, I'd like to templatize the return value, too. So instead of: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); I'd have: template<class return_t, class InputIterator, class Predicate> static return_t findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); How would I specify that: 1) return_t must be a set of some sort 2) InputIterator must be an iterator 3) InputIterator's type must work with return_t's type. Thanks.

    Read the article

  • Why does Scala apply thunks automatically, sometimes?

    - by Anonymouse
    At just after 2:40 in ShadowofCatron's Scala Tutorial 3 video, it's pointed out that the parentheses following the name of a thunk are optional. "Buh?" said my functional programming brain, since the value of a function and the value it evaluates to when applied are completely different things. So I wrote the following to try this out. My thought process is described in the comments. object Main { var counter: Int = 10 def f(): Int = { counter = counter + 1; counter } def runThunk(t: () => Int): Int = { t() } def main(args: Array[String]): Unit = { val a = f() // I expect this to mean "apply f to no args" println(a) // and apparently it does val b = f // I expect this to mean "the value f", a function value println(b) // but it's the value it evaluates to when applied to no args println(b) // and the evaluation happens immediately, not in the call runThunk(b) // This is an error: it's not println doing something funny runThunk(f) // Not an error: seems to be val doing something funny } }   To be clear about the problem, this Scheme program (and the console dump which follows) shows what I expected the Scala program to do. (define counter (list 10)) (define f (lambda () (set-car! counter (+ (car counter) 1)) (car counter))) (define runThunk (lambda (t) (t))) (define main (lambda args (let ((a (f)) (b f)) (display a) (newline) (display b) (newline) (display b) (newline) (runThunk b) (runThunk f)))) > (main) 11 #<procedure:f> #<procedure:f> 13   After coming to this site to ask about this, I came across this answer which told me how to fix the above Scala program: val b = f _ // Hey Scala, I mean f, not f() But the underscore 'hint' is only needed sometimes. When I call runThunk(f), no hint is required. But when I 'alias' f to b with a val then apply it, it doesn't work: the evaluation happens in the val; and even lazy val works this way, so it's not the point of evaluation causing this behaviour.   That all leaves me with the question: Why does Scala sometimes automatically apply thunks when evaluating them? Is it, as I suspect, type inference? And if so, shouldn't a type system stay out of the language's semantics? Is this a good idea? Do Scala programmers apply thunks rather than refer to their values so much more often that making the parens optional is better overall? Examples written using Scala 2.8.0RC3, DrScheme 4.0.1 in R5RS.

    Read the article

  • App logicstics & changes due to scope creep

    - by Kevin Brown
    I started an app that was initially a testing platform--user management, and managers that can view their employees tests. Recently, functionality has been extended (not built yet) to allow users to complete a test in place of an employee--basically adding a record, but no user. I have three tables in use for this: users(contains user info for login/security), profiles (all personal info: address, height, etc.), and survey (contains survey answers for user). How do I extend my application to encompass this functionality with minimal change to the structure? I assume that the best way to do this would be to insert records to the tables profiles and survey, and have no username/password/email? There MUST be a user_id associated b/c the tables are linked through the user_ids...

    Read the article

  • How to deal with clients and iterations in Agile team?

    - by Ondrej Slinták
    This thread is a follow up to my previous one. It's in fact 2 questions, so I hope no one minds, as they are dependent on each other. We are starting a new project at work and we consider it as a great opportunity to try Agile techniques in action. We had a brainstorming about ideas we read in several books and articles, and came up with concept that would suit us the best: 2 weeks iteration, followed by call with clients who would choose what stuff they want to have in next iteration. I just have few more questions, which we couldn't figure out ourselves. What to do in the first iteration? What to, generally, do in the first few iterations if we start from the scratch? Just give it a month of development to code core of the application or start with simple wire-frames with limited pre-coded functionality? What usually clients want to see? Shiny stuff that doesn't work or ugly stuff that does work? How to communicate with clients? Our initial thought it to set the process to something like this: Is it a good idea to have a Focal Point on client side or is it better to communicate straight with all the clients to prevent miscommunication? Any thoughts are welcome! Thanks in advance.

    Read the article

  • I need to speed up a function. Should I use cython, ctypes, or something else?

    - by Peter Stewart
    I'm having a lot of fun learning Python by writing a genetic programming type of application. I've had some great advice from Torsten Marek, Paul Hankin and Alex Martelli on this site. The program has 4 main functions: generate (randomly) an expression tree. evaluate the fitness of the tree crossbreed mutate As all of generate, crossbreed and mutate call 'evaluate the fitness'. it is the busiest function and is the primary bottleneck speedwise. As is the nature of genetic algorithms, it has to search an immense solution space so the faster the better. I want to speed up each of these functions. I'll start with the fitness evaluator. My question is what is the best way to do this. I've been looking into cython, ctypes and 'linking and embedding'. They are all new to me and quite beyond me at the moment but I look forward to learning one and eventually all of them. The 'fitness function' needs to compare the value of the expression tree to the value of the target expression. So it will consist of a postfix evaluator which will read the tree in a postfix order. I have all the code in python. I need advice on which I should learn and use now: cython, ctypes or linking and embedding. Thank you.

    Read the article

  • Dijkstra's Algorithm explanation java

    - by alchemey89
    Hi, I have found an implementation for dijkstras algorithm on the internet and was wondering if someone could help me understand how the code works. Many thanks private int nr_points=0; private int[][]Cost; private int []mask; private void dijkstraTSP() { if(nr_points==0)return; //algorithm=new String("Dijkstra"); nod1=new Vector(); nod2=new Vector(); weight=new Vector(); mask=new int[nr_points]; //initialise mask with zeros (mask[x]=1 means the vertex is marked as used) for(int i=0;i<nr_points;i++)mask[i]=0; //Dijkstra: int []dd=new int[nr_points]; int []pre=new int[nr_points]; int []path=new int[nr_points+1]; int init_vert=0,pos_in_path=0,new_vert=0; //initialise the vectors for(int i=0;i<nr_points;i++) { dd[i]=Cost[init_vert][i]; pre[i]=init_vert; path[i]=-1; } pre[init_vert]=0; path[0]=init_vert; pos_in_path++; mask[init_vert]=1; for(int k=0;k<nr_points-1;k++) { //find min. cost in dd for(int j=0;j<nr_points;j++) if(dd[j]!=0 && mask[j]==0){new_vert=j; break;} for(int j=0;j<nr_points;j++) if(dd[j]<dd[new_vert] && mask[j]==0 && dd[j]!=0)new_vert=j; mask[new_vert]=1; path[pos_in_path]=new_vert; pos_in_path++; for(int j=0;j<nr_points;j++) { if(mask[j]==0) { if(dd[j]>dd[new_vert]+Cost[new_vert][j]) { dd[j]=dd[new_vert]+Cost[new_vert][j]; } } } } //Close the cycle path[nr_points]=init_vert; //Save the solution in 3 vectors (for graphical purposes) for(int i=0;i<nr_points;i++) { nod1.addElement(path[i]); nod2.addElement(path[i+1]); weight.addElement(Cost[path[i]][path[i+1]]); } }

    Read the article

  • Formula to follow addition of rows

    - by Wayne McCaslin
    New to VBA, please help. I have a range say A2:D10; input causes rows to be added. New entries are being added using NextRow=_. Works perfectly, however, how do I get the formulas in columns C and D to follow each new row being added. I cannot just format entire column due to my sort criteria. Example formula is =IF(ISTEXT($B11),$C$2-$D11,"")

    Read the article

  • jquery tooltip shows a div's content

    - by bob
    Hello, I want to use either http://onehackoranother.com/projects/jquery/tipsy/ or http://bassistance.de/jquery-plugins/jquery-plugin-tooltip/ and I was wondering if lets say I have a div on my page that has a class 'item_info'. Can I have my tooltip that is created output the div inside the tooltip and formatted properly according to my css? Is there another plugin I should be looking into? Thanks. I hope this is clear enough.

    Read the article

  • How to make a php function contain mysql commands

    - by bob
    I want to create a simple menu function which can call it example get_menu() Here is my current code. <?php $select = 'SELECT * FROM pages'; $query = $db->rq($select); while ($page = $db->fetch($query)) { $id = $page['id']; $title = $page['title']; ?> <a href="page.php?id<?php echo $id; ?>" title="<?php echo $title; ?>"><?php echo $title; ?></a> <?php } ?> How to do that in? function get_menu() { } Let me know.

    Read the article

< Previous Page | 38 39 40 41 42 43 44 45 46 47 48 49  | Next Page >