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  • Call methods in main method

    - by Niloo
    this is my main method that gets 3 integers from command line and I parse then in my validating method. However I have one operation method that calls 3 other methods, but i don't know what type of data and howmany I have to put in my operatinMethod() " cuase switch only gets one); AND also in my mainMethod() for calling the operationMehod(); itself? please let me know if i'm not clear? Thanx! main method: public class test { // Global Constants final static int MIN_NUMBER = 1; final static int MAX_PRIME = 10000; final static int MAX_FACTORIAL = 12; final static int MAX_LEAPYEAR = 4000; //Global Variables static int a,b,c; public static void main (String[] args) { for(int i =0; i< args.length; i++){} if(validateInput(args[0],args[1],args[2])){ performOperations(); } } //Validate User Input public static boolean validateInput(String num1,String num2,String num3){ boolean isValid = false; try{ try{ try{ a = Integer.parseInt(num1); if(!withinRange(a,MIN_NUMBER, MAX_PRIME)) { System.out.println("The entered value " + num1 +" is out of range [1 TO 10000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num1 + " is not a valid integer. Please try again."); } b = Integer.parseInt(num2); if(!withinRange(b,MIN_NUMBER, MAX_FACTORIAL)) { System.out.println("The entered value " + num2 +" is out of range [1 TO 12]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num2 + " is not a valid integer. Please try again."); } c = Integer.parseInt(num3); if(!withinRange(c,MIN_NUMBER, MAX_LEAPYEAR)) { System.out.println("The entered value " + num3 +" is out of range [1 TO 4000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num3 + " is not a valid integer. Please try again."); } return isValid; } //Check the value within the specified range private static boolean withinRange(int userInput ,int min, int max){ boolean isInRange = true; if(userInput < min || userInput > max){ isInRange = false; } return isInRange; } //Perform operations private static void performOperations(int userInput) { switch(userInput) { case 1: // count Prime numbers countPrimes(a); break; case 2: // Calculate factorial getFactorial(b); break; case 3: // find Leap year isLeapYear(c); break; } } // Verify Prime Number private static boolean isPrime(int prime) { for(int i = 2; i <= Math.sqrt(prime) ; i++) { if ((prime % i) == 0) { return false; } } return true; } // Calculate Prime private static int countPrimes(int userInput){ int count =0; for(int i=userInput; i<=MAX_PRIME; i++) { if(isPrime(i)){ count++; } } System.out.println("Exactly "+ count + " prime numbers exist between "+ a + " and 10,000."); return count; } // Calculate the factorial value private static int getFactorial(int userInput){ int ans = userInput; if(userInput >1 ){ ans*= (getFactorial(userInput-1)); //System.out.println("The value of "+ b +"! is "+ getFactorial(userInput)); } return ans; } // Determine whether the integer represents a leap year private static boolean isLeapYear(int userInput){ if (userInput % 4 == 0 && userInput % 400 == 0 && userInput % 100 ==0){ System.out.println("The year "+ c +" is a leap year"); } else { System.out.println("The year "+ c +" is a not leap year"); } return false; } }

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  • Matlab Image watermarking question , using both SVD and DWT

    - by Georgek
    Hello all . here is a code that i got over the net ,and it is supposed to embed a watermark of size(50*20) called _copyright.bmp in the Code below . the size of the cover object is (512*512), it is called _lena_std_bw.bmp.What we did here is we did DWT2 2 times for the image , when we reached our second dwt2 cA2 size is 128*128. You should notice that the blocksize and it equals 4, it is used to determine the max msg size based on cA2 according to the following code:max_message=RcA2*CcA2/(blocksize^2). in our current case max_message would equal 128*128/(4^2)=1024. i want to embed a bigger watermark in the 2nd dwt2 and lets say the size of that watermark is 400*10(i can change the dimension using MS PAINT), what i have to do is change the size of the blocksize to 2. so max_message=4096.Matlab gives me 3 errors and they are : ??? Error using == plus Matrix dimensions must agree. Error in == idwt2 at 93 x = upsconv2(a,{Lo_R,Lo_R},sx,dwtEXTM,shift)+ ... % Approximation. Error in == two_dwt_svd_low_low at 88 CAA1 = idwt2(cA22,cH2,cV2,cD2,'haar',[RcA1,CcA1]); The origional Code is (the origional code where blocksize =4): %This algorithm makes DWT for the whole image and after that make DWT for %cH1 and make SVD for cH2 and embed the watermark in every level after SVD %(1) -------------- Embed Watermark ------------------------------------ %Add the watermar W to original image I and give the watermarked image in J %-------------------------------------------------------------------------- % set the gain factor for embeding and threshold for evaluation clc; clear all; close all; % save start time start_time=cputime; % set the value of threshold and alpha thresh=.5; alpha =0.01; % read in the cover object file_name='_lena_std_bw.bmp'; cover_object=double(imread(file_name)); % determine size of watermarked image Mc=size(cover_object,1); %Height Nc=size(cover_object,2); %Width % read in the message image and reshape it into a vector file_name='_copyright.bmp'; message=double(imread(file_name)); T=message; Mm=size(message,1); %Height Nm=size(message,2); %Width % perform 1-level DWT for the whole cover image [cA1,cH1,cV1,cD1] = dwt2(cover_object,'haar'); % determine the size of cA1 [RcA1 CcA1]=size(cA1) % perform 2-level DWT for cA1 [cA2,cH2,cV2,cD2] = dwt2(cA1,'haar'); % determine the size of cA2 [RcA2 CcA2]=size(cA2) % set the value of blocksize blocksize=4 % reshape the watermark to a vector message_vector=round(reshape(message,Mm*Nm,1)./256); W=message_vector; % determine maximum message size based on cA2, and blocksize max_message=RcA2*CcA2/(blocksize^2) % check that the message isn't too large for cover if (length(message) max_message) error('Message too large to fit in Cover Object') end %----------------------- process the image in blocks ---------------------- x=1; y=1; for (kk = 1:length(message_vector)) [cA2u cA2s cA2v]=svd(cA2(y:y+blocksize-1,x:x+blocksize-1)); % if message bit contains zero, modify S of the original image if (message_vector(kk) == 0) cA2s = cA2s*(1 + alpha); % otherwise mask is filled with zeros else cA2s=cA2s; end cA22(y:y+blocksize-1,x:x+blocksize-1)=cA2u*cA2s*cA2v; % move to next block of mask along x; If at end of row, move to next row if (x+blocksize) >= CcA2 x=1; y=y+blocksize; else x=x+blocksize; end end % perform IDWT CAA1 = idwt2(cA22,cH2,cV2,cD2,'haar',[RcA1,CcA1]); watermarked_image= idwt2(CAA1,cH1,cV1,cD1,'haar',[Mc,Nc]); % convert back to uint8 watermarked_image_uint8=uint8(watermarked_image); % write watermarked Image to file imwrite(watermarked_image_uint8,'dwt_watermarked.bmp','bmp'); % display watermarked image figure(1) imshow(watermarked_image_uint8,[]) title('Watermarked Image') %(2) ---------------------------------------------------------------------- %---------- Extract Watermark from attacked watermarked image ------------- %-------------------------------------------------------------------------- % read in the watermarked object file_name='dwt_watermarked.bmp'; watermarked_image=double(imread(file_name)); % determine size of watermarked image Mw=size(watermarked_image,1); %Height Nw=size(watermarked_image,2); %Width % perform 1-level DWT for the whole watermarked image [ca1,ch1,cv1,cd1] = dwt2(watermarked_image,'haar'); % determine the size of ca1 [Rca1 Cca1]=size(ca1); % perform 2-level DWT for ca1 [ca2,ch2,cv2,cd2] = dwt2(ca1,'haar'); % determine the size of ca2 [Rca2 Cca2]=size(ca2); % process the image in blocks % for each block get a bit for message x=1; y=1; for (kk = 1:length(message_vector)) % sets correlation to 1 when patterns are identical to avoid /0 errors % otherwise calcluate difference between the cover image and the % watermarked image [cA2u cA2s cA2v]=svd(cA2(y:y+blocksize-1,x:x+blocksize-1)); [ca2u1 ca2s1 ca2v1]=svd(ca2(y:y+blocksize-1,x:x+blocksize-1)); correlation(kk)=diag(ca2s1-cA2s)'*diag(ca2s1-cA2s)/(alpha*alpha)/(diag(cA2s)*diag(cA2s)); % move on to next block. At and of row move to next row if (x+blocksize) >= Cca2 x=1; y=y+blocksize; else x=x+blocksize; end end % if correlation exceeds average correlation correlation(kk)=correlation(kk)+mean(correlation(1:Mm*Nm)); for kk = 1:length(correlation) if (correlation(kk) > thresh*alpha);%thresh*mean(correlation(1:Mo*No))) message_vector(kk)=0; end end % reshape the message vector and display recovered watermark. figure(2) message=reshape(message_vector(1:Mm*Nm),Mm,Nm); imshow(message,[]) title('Recovered Watermark') % display processing time elapsed_time=cputime-start_time, please do help,its my graduation project and i have been trying this code for along time but failed miserable. Thanks in advance

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  • Where to look for real url

    - by smallB
    I'm trying to write simple application for downloading videos from youtube. My code for getting file (http://www.youtube.com/watch?v=pViMzR_ylXg) looks like: bool FD_core::get_file() { QNetworkRequest request; request.setUrl(QUrl("http://www.youtube.com/watch?v=pViMzR_ylXg")); connect(network_access_manager_, SIGNAL(finished(QNetworkReply*)), this, SLOT(onRequestCompleted(QNetworkReply *))); network_access_manager_->get(request); return true; } void FD_core::onRequestCompleted(QNetworkReply * reply) { QByteArray data_ = reply->readAll(); cout << data_.constData(); qDebug() << "size: " << data_.size(); } In the above function data_.constData() produces lots of text, part (very small) of it: <!DOCTYPE html> <html lang="en" dir="ltr" > <head> <script> var yt = yt || {};yt.timing = yt.timing || {};yt.timing.tick = function(label, opt_time) {var timer = yt.timing['timer'] || {};if(opt_time) {timer[label] = opt_time;}else {timer[label] = new Date().getTime();}yt.timing['timer'] = timer;};yt.timing.info = function(label, value) {var info_args = yt.timing['info_args'] || {};info_args[label] = value;yt.timing['info_args'] = info_args;};yt.timing.info('e', "907050,906359,927900,919320,914021,916611,922401,920704,912806,927201,925706,928001,922403,913546,913556,920201,911116,901451");yt.timing.wff = true;yt.timing.info('pr', "1");yt.timing.info('an', "dclk,aftv,afv");if (document.webkitVisibilityState == 'prerender') {document.addEventListener('webkitvisibilitychange', function() {yt.timing.tick('start');}, false);}yt.timing.tick('start');yt.timing.info('li','0');try {yt.timing['srt'] = window.gtbExternal && window.gtbExternal.pageT() ||window.external && window.external.pageT;} catch(e) {}if (window.chrome && window.chrome.csi) {yt.timing['srt'] = Math.floor(window.chrome.csi().pageT);}if (window.msPerformance && window.msPerformance.timing) {yt.timing['srt'] = window.msPerformance.timing.responseStart - window.msPerformance.timing.navigationStart;} </script> <script>var yt = yt || {};yt.preload = {};yt.preload.counter_ = 0;yt.preload.start = function(src) {var img = new Image();var counter = ++yt.preload.counter_;yt.preload[counter] = img;img.onload = img.onerror = function () {delete yt.preload[counter];};img.src = src;img = null;};yt.preload.start("http:\/\/o-o---preferred---sn-xn5ucu-q0ce---v3---lscache7.c.youtube.com\/crossdomain.xml");yt.preload.start("http:\/\/o-o---preferred---sn-xn5ucu-q0ce---v3---lscache7.c.youtube.com\/generate_204?ip=95.83.224.63\u0026upn=A3aUhLYV55M\u0026sparams=algorithm%2Cburst%2Ccp%2Cfactor%2Cgcr%2Cid%2Cip%2Cipbits%2Citag%2Csource%2Cupn%2Cexpire\u0026fexp=907050%2C906359%2C927900%2C919320%2C914021%2C916611%2C922401%2C920704%2C912806%2C927201%2C925706%2C928001%2C922403%2C913546%2C913556%2C920201%2C911116%2C901451\u0026mt=1354207274\u0026key=yt1\u0026algorithm=throttle-factor\u0026burst=40\u0026ipbits=8\u0026itag=34\u0026sver=3\u0026signature=692E605215EB4D2CA407291CA26E14B844768A89.7A2930CE25FDDFC7C4FF5AA56DD02538B0020267\u0026mv=m\u0026source=youtube\u0026ms=au\u0026gcr=ie\u0026expire=1354228237\u0026factor=1.25\u0026cp=U0hUSVJNVl9IUUNONF9KR1pDOi0tSFhhRzVFRkd6\u0026id=a5588ccd1ff29578");</script><title>Die Antwoord - Fok Julle Naaiers (Mike Tyson&#39;s Words NOT DJ Hi-Teks) - YouTube</title><link rel="search" type="application/opensearchdescription+xml" href="http://www.youtube.com/opensearch?locale=en_US" title="YouTube Video Search"><link rel="icon" href="http://s.ytimg.com/yts/img/favicon-vfldLzJxy.ico" type="image/x-icon"><link rel="shortcut icon" href="http://s.ytimg.com/yts/img/favicon-vfldLzJxy.ico" type="image/x-icon"> <link rel="icon" href="//s.ytimg.com/yts/img/favicon_32-vflWoMFGx.png" sizes="32x32"><link rel="canonical" href="/watch?v=pViMzR_ylXg"><link rel="alternate" media="handheld" href="http://m.youtube.com/watch?v=pViMzR_ylXg"><link rel="alternate" media="only screen and (max-width: 640px)" href="http://m.youtube.com/watch?v=pViMzR_ylXg"><link rel="shortlink" href="http://youtu.be/pViMzR_ylXg"> <meta name="title" content="Die Antwoord - Fok Julle Naaiers (Mike Tyson&#39;s Words NOT DJ Hi-Teks)"> <meta name="description" content="Some of the lyrics of &quot;Die Antwoord&quot; new single &quot;Fok Julle Naaiers&quot; have caused such controversy that Die Antwoord have split with their record label Intersc..."> <meta name="keywords" content="Die Antwoord, Fok Julle Naaiers, Mike Tyson, DJ Hi-Tek, Faggot"> <link rel="alternate" type="application/json+oembed" href="http://www.youtube.com/oembed?url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DpViMzR_ylXg&amp;format=json" title="Die Antwoord - Fok Julle Naaiers (Mike Tyson&#39;s Words NOT DJ Hi-Teks)"> <link rel="alternate" type="text/xml+oembed" href="http://www.youtube.com/oembed?url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DpViMzR_ylXg&amp;format=xml" title="Die Antwoord - Fok Julle Naaiers (Mike Tyson&#39;s Words NOT DJ Hi-Teks)"> <meta property="og:url" content="http://www.youtube.com/watch?v=pViMzR_ylXg"> <meta property="og:title" content="Die Antwoord - Fok Julle Naaiers (Mike Tyson&#39;s Words NOT DJ Hi-Teks)"> <meta property="og:description" content="Some of the lyrics of &quot;Die Antwoord&quot; new single &quot;Fok Julle Naaiers&quot; have caused such controversy that Die Antwoord have split with their record label Intersc..."> <meta property="og:type" content="video"> <meta property="og:image" content="http://i1.ytimg.com/vi/pViMzR_ylXg/mqdefault.jpg"> <meta property="og:video" content="http://www.youtube.com/v/pViMzR_ylXg?version=3&amp;autohide=1"> <meta property="og:video:type" content="application/x-shockwave-flash"> <meta property="og:video:width" content="853"> <meta property="og:video:height" content="480"> <meta property="og:site_name" content="YouTube"> <meta property="fb:app_id" content="87741124305"> <meta name="twitter:card" value="player"> <meta name="twitter:site" value="@youtube"> <meta name="twitter:player" value="https://www.youtube.com/embed/pViMzR_ylXg"> <meta property="twitter:player:width" content="853"> <meta property="twitter:player:height" content="480"> So my question is, where in this file is the url hidden which will allow me to download the wanted file?

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  • Of these 3 methods for reading linked lists from shared memory, why is the 3rd fastest?

    - by Joseph Garvin
    I have a 'server' program that updates many linked lists in shared memory in response to external events. I want client programs to notice an update on any of the lists as quickly as possible (lowest latency). The server marks a linked list's node's state_ as FILLED once its data is filled in and its next pointer has been set to a valid location. Until then, its state_ is NOT_FILLED_YET. I am using memory barriers to make sure that clients don't see the state_ as FILLED before the data within is actually ready (and it seems to work, I never see corrupt data). Also, state_ is volatile to be sure the compiler doesn't lift the client's checking of it out of loops. Keeping the server code exactly the same, I've come up with 3 different methods for the client to scan the linked lists for changes. The question is: Why is the 3rd method fastest? Method 1: Round robin over all the linked lists (called 'channels') continuously, looking to see if any nodes have changed to 'FILLED': void method_one() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { Data* current_item = channel_cursors[i]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[i] = static_cast<Data*>(current_item->next_.get(segment)); } } } Method 1 gave very low latency when then number of channels was small. But when the number of channels grew (250K+) it became very slow because of looping over all the channels. So I tried... Method 2: Give each linked list an ID. Keep a separate 'update list' to the side. Every time one of the linked lists is updated, push its ID on to the update list. Now we just need to monitor the single update list, and check the IDs we get from it. void method_two() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { if(update_cursor->state_ == NOT_FILLED_YET) { continue; } ::uint32_t update_id = update_cursor->list_id_; Data* current_item = channel_cursors[update_id]; if(current_item->state_ == NOT_FILLED_YET) { std::cerr << "This should never print." << std::endl; // it doesn't continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[update_id] = static_cast<Data*>(current_item->next_.get(segment)); update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } } Method 2 gave TERRIBLE latency. Whereas Method 1 might give under 10us latency, Method 2 would inexplicably often given 8ms latency! Using gettimeofday it appears that the change in update_cursor-state_ was very slow to propogate from the server's view to the client's (I'm on a multicore box, so I assume the delay is due to cache). So I tried a hybrid approach... Method 3: Keep the update list. But loop over all the channels continuously, and within each iteration check if the update list has updated. If it has, go with the number pushed onto it. If it hasn't, check the channel we've currently iterated to. void method_three() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { std::size_t idx = i; ACQUIRE_MEMORY_BARRIER; if(update_cursor->state_ != NOT_FILLED_YET) { //std::cerr << "Found via update" << std::endl; i--; idx = update_cursor->list_id_; update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } Data* current_item = channel_cursors[idx]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } found_an_update = true; log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[idx] = static_cast<Data*>(current_item->next_.get(segment)); } } } The latency of this method was as good as Method 1, but scaled to large numbers of channels. The problem is, I have no clue why. Just to throw a wrench in things: if I uncomment the 'found via update' part, it prints between EVERY LATENCY LOG MESSAGE. Which means things are only ever found on the update list! So I don't understand how this method can be faster than method 2. The full, compilable code (requires GCC and boost-1.41) that generates random strings as test data is at: http://pastebin.com/e3HuL0nr

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  • problems in trying ieee 802.15.4 working from msk

    - by asel
    Hi, i took a msk code from dsplog.com and tried to modify it to test the ieee 802.15.4. There are several links on that site for ieee 802.15.4. Currently I am getting simulated ber results all approximately same for all the cases of Eb_No values. Can you help me to find why? thanks in advance! clear PN = [ 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0; 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0; 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0; 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1; 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0 0 0 1 1; 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 0; 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 1; 1 0 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 0 1 1 0 1; 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1; 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1; 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1; 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0; 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 1 1 0; 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1; 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 1 1 0 0; 1 1 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0; ]; N = 5*10^5; % number of bits or symbols fsHz = 1; % sampling period T = 4; % symbol duration Eb_N0_dB = [0:10]; % multiple Eb/N0 values ct = cos(pi*[-T:N*T-1]/(2*T)); st = sin(pi*[-T:N*T-1]/(2*T)); for ii = 1:length(Eb_N0_dB) tx = []; % MSK Transmitter ipBit = round(rand(1,N/32)*15); for k=1:length(ipBit) sym = ipBit(k); tx = [tx PN((sym+1),1:end)]; end ipMod = 2*tx - 1; % BPSK modulation 0 -> -1, 1 -> 1 ai = kron(ipMod(1:2:end),ones(1,2*T)); % even bits aq = kron(ipMod(2:2:end),ones(1,2*T)); % odd bits ai = [ai zeros(1,T) ]; % padding with zero to make the matrix dimension match aq = [zeros(1,T) aq ]; % adding delay of T for Q-arm % MSK transmit waveform xt = 1/sqrt(T)*[ai.*ct + j*aq.*st]; % Additive White Gaussian Noise nt = 1/sqrt(2)*[randn(1,N*T+T) + j*randn(1,N*T+T)]; % white gaussian noise, 0dB variance % Noise addition yt = xt + 10^(-Eb_N0_dB(ii)/20)*nt; % additive white gaussian noise % MSK receiver % multiplying with cosine and sine waveforms xE = conv(real(yt).*ct,ones(1,2*T)); xO = conv(imag(yt).*st,ones(1,2*T)); bHat = zeros(1,N); bHat(1:2:end) = xE(2*T+1:2*T:end-2*T); % even bits bHat(2:2:end) = xO(3*T+1:2*T:end-T); % odd bits result=zeros(16,1); chiplen=32; seqstart=1; recovered = []; while(seqstart<length(bHat)) A = bHat(seqstart:seqstart+(chiplen-1)); for j=1:16 B = PN(j,1:end); result(j)=sum(A.*B); end [value,index] = max(result); recovered = [recovered (index-1)]; seqstart = seqstart+chiplen; end; %# create binary string - the 4 forces at least 4 bits bstr1 = dec2bin(ipBit,4); bstr2 = dec2bin(recovered,4); %# convert back to numbers (reshape so that zeros are preserved) out1 = str2num(reshape(bstr1',[],1))'; out2 = str2num(reshape(bstr2',[],1))'; % counting the errors nErr(ii) = size(find([out1 - out2]),2); end nErr/(length(ipBit)*4) % simulated ber theoryBer = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))) % theoretical ber

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  • Representing robot's elbow angle in 3-D

    - by Onkar Deshpande
    I am given coordinates of two points in 3-D viz. shoulder point and object point(to which I am supposed to reach). I am also given the length from my shoulder-to-elbow arm and the length of my forearm. I am trying to solve for the unknown position(the position of the joint elbow). I am using cosine rule to find out the elbow angle. Here is my code - #include <stdio.h> #include <math.h> #include <stdlib.h> struct point { double x, y, z; }; struct angles { double clock_wise; double counter_clock_wise; }; double max(double a, double b) { return (a > b) ? a : b; } /* * Check if the combination can make a triangle by considering the fact that sum * of any two sides of a triangle is greater than the remaining side. The * overlapping condition of links is handled separately in main(). */ int valid_triangle(struct point p0, double l0, struct point p1, double l1) { double dist = sqrt(pow((fabs(p1.z - p0.z)), 2) + pow((fabs(p1.y - p0.y)), 2) + pow((fabs(p1.x - p0.x)), 2)); if((max(dist, l0) == dist) && max(dist, l1) == dist) { return (dist < (l0 + l1)); } else if((max(dist, l0) == l0) && (max(l0, l1) == l0)) { return (l0 < (dist + l1)); } else { return (l1 < (dist + l0)); } } /* * Cosine rule is used to find the elbow angle. Positive value indicates a * counter clockwise angle while negative value indicates a clockwise angle. * Since this problem has at max 2 solutions for any given position of P0 and * P1, I am returning a structure of angles which can be used to consider angles * from both direction viz. clockwise-negative and counter-clockwise-positive */ void return_config(struct point p0, double l0, struct point p1, double l1, struct angles *a) { double dist = sqrt(pow((fabs(p1.z - p0.z)), 2) + pow((fabs(p1.y - p0.y)), 2) + pow((fabs(p1.x - p0.x)), 2)); double degrees = (double) acos((l0 * l0 + l1 * l1 - dist * dist) / (2 * l0 * l1)) * (180.0f / 3.1415f); a->clock_wise = -degrees; a->counter_clock_wise = degrees; } int main() { struct point p0, p1; struct angles a; p0.x = 15, p0.y = 4, p0.z = 0; p1.x = 20, p1.y = 4, p1.z = 0; double l0 = 5, l1 = 8; if(valid_triangle(p0, l0, p1, l1)) { printf("Three lengths can make a valid configuration \n"); return_config(p0, l0, p1, l1, &a); printf("Angle of the elbow point (clockwise) = %lf, (counter clockwise) = %lf \n", a.clock_wise, a.counter_clock_wise); } else { double dist = sqrt(pow((fabs(p1.z - p0.z)), 2) + pow((fabs(p1.y - p0.y)), 2) + pow((fabs(p1.x - p0.x)), 2)); if((dist <= (l0 + l1)) && (dist > l0)) { a.clock_wise = -180.0f; a.counter_clock_wise = 180.0f; printf("Angle of the elbow point (clockwise) = %lf, (counter clockwise) = %lf \n", a.clock_wise, a.counter_clock_wise); } else if((dist <= fabs(l0 - l1)) && (dist < l0)){ a.clock_wise = -0.0f; a.counter_clock_wise = 0.0f; printf("Angle of the elbow point (clockwise) = %lf, (counter clockwise) = %lf \n", a.clock_wise, a.counter_clock_wise); } else printf("Given combination cannot make a valid configuration\n"); } return 0; } However, this solution makes sense only in 2-D. Because clockwise and counter-clockwise are meaningless without an axis and direction of rotation. Returning only an angle is technically correct but it leaves a lot of work for the client of this function to use the result in meaningful way. How can I make the changes to get the axis and direction of rotation ? Also, I want to know how many possible solution could be there for this problem. Please let me know your thoughts ! Any help is highly appreciated ...

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  • Multiple routers, subnets, gateways etc

    - by allentown
    My current setup is: Cable modem dishes out 13 static IP's (/28), a GB switch is plugged into the cable modem, and has access to those 13 static IP's, I have about 6 "servers" in use right now. The cable modem is also a firewall, DHCP server, and 3 port 10/100 switch. I am using it as a firewall, but not currently as a DHCP server. I have plugged into the cable modem, two network cables, one which goes to the WAN port of a Linksys Dual Band Wireless 10/100/1000 router/switch. Into the linksys are a few workstations, a few printers, and some laptops connecting to wifi. I set the Linksys to use take static IP, and enabled DHCP for the workstations, printers, etc in 192.168.1.1/24. The network for the Linksys is mostly self contained, backups go to a SAN, on that network, it all happens through that switch, over GB. But I also get internet access from it as well via the cable modem using one static IP. This all works, however, I can not "see" the static IP machines when I am on the Linksys. I can get to them via ssh and other protocols, and if I want to from "outside", I open holes, like 80, 25, 587, 143, 22, etc. The second wire, from the cable modem/fireall/switch just uplinks to the managed GB switch. What are the pros and cons of this? I do not like giving up the static IP to the Linksys. I basically have a mixed network of public servers, and internal workstations. I want the public servers on public IP's because I do not want to mess with port forwarding and mappings. Is it correct also, that if someone breaches the Linksys wifi, they still would have a hard time getting to the static IP range, just by nature of the network topology? Today, just for a test, I toggled on the DHCP in the firewall/cable modem at 10.1.10.1/24 range, the Linksys is n the 192.168.1.100/24 range. At that point, all the static IP machines still had in and out access, but Linksys was unreachable. The cable modem only has 10/100 ports, so I will not plug anything but the network drop into it, which is 50Mb/10Mb. Which makes me think this could be less than ideal, as transfers from the workstation network to the server network will be bottlenecked at 100Mb when I have 1000Mb available. I may not need to solve that, if isolation is better though. I do not move a lot of data, if any, from Linsys network to server network, so for it to pretend to be remote is ok. Should I approach this any different? I could enable DHCP on the cable modem/firewall, it should still send out the statics to the GB switch, but will also be a DHCP in 10.1.10.1/24 range? I can then plug the Linksys into the GB switch, which is now picking up statics and the 10.1.10.1/24 ranges, tell the Linksys to use 10.1.10.5 or so. Now, do I disable DHCP on the Linksys, and the cable modem/firewall will pass through the statics and 10.0.10.1/24 ranges as well? Or, could I open a second DHCP pool on the Linksys? I guess doing so gives me network isolation again, but it is just the reverse of what I have now. But I get out of the bottleneck, not that the Linksys could ever really touch real GB speeds anyway, but the managed switch certainly can. This is all because 13 statics are not that many. Right now, 6 "servers", the Linksys, a managed switch, a few SSL certs, and I am running out. I do not want to waste a static IP on the managed GB switch, or the Linksys, unless it provides me some type of benefit. Final question, under my current setup, if I am on a workstation, sitting at 192.168.1.109, the Linksys, with GB, and I send a file over ssh to the static IP machine, is that literally leaving the internet, and coming back in, or does it stay local? To me it seems like: Workstation (192.168.1.109) -> Linksys DHCP -> Linksys Static IP -> Cable Modem -> Server ( and it hits the 10/100 ports on the cable modem, slowing me down. But does it round trip the network, leave and come back in, limiting me to the 50/10 internet speeds? *These are all made up numbers, I do not use default router IP's as I will one day add a VPN, and do not want collisions. I need some recommendations, do I want one big network, or two isolated ones. Printers these days need an IP, everything does, I can not get autoconf/bonjour to be reliable on most printers. but I am also not sure I want the "server" side of my operation to be polluted by the workstation side of my operation. Unless there is some magic subetting I have not learned yet, here is what I am thinking: Cable modem 10/100, has 13 static IP, publicly accessible -> Enable DHCP on the cable modem -> Cable modem plugs into managed switch -> Managed switch gets 10.1.10.1 ssh, telnet, https admin management address -> Managed switch sends static IP's to to servers -> Plug Linksys into managed switch, giving it 10.1.10.2 static internally in Linksys admin -> Linksys gets assigned 10.1.10.x as its DHCP sending range -> Local printers, workstations, iPhones etc, connect to this -> ( Do I enable DHCP or disable it on the Linksys, just define a non over lapping range, or create an entirely new DHCP at 10.1.50.0/24, I think I am back isolated again with that method too? ) Thank you for any suggestions. This is the first time I have had to deal with less than a /24, and most are larger than that, but it is just a drop to a cabinet. Otherwise, it's a router, a few repeaters, and soho stuff that is simple, with one IP. I know a few may suggest going all DHCP on the servers, and I may one day, just not now, there has been too much moving of gear for me to be interested in that, and I would want something in the Catalyst series to deal with that.

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  • improving conversions to binary and back in C#

    - by Saad Imran.
    I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes. I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users. So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help. GSBitConverter.cs This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type. public static class GSBitConverter { public static byte[] ToGSBinary(this short value) { return BitConverter.GetBytes(value); } public static byte[] ToGSBinary(this IEnumerable<short> value) { List<byte> bytes = new List<byte>(); short length = (short)value.Count(); bytes.AddRange(length.ToGSBinary()); for (int i = 0; i < length; i++) bytes.AddRange(value.ElementAt(i).ToGSBinary()); return bytes.ToArray(); } public static byte[] ToGSBinary(this bool value); public static byte[] ToGSBinary(this IEnumerable<bool> value); public static byte[] ToGSBinary(this IEnumerable<byte> value); public static byte[] ToGSBinary(this int value); public static byte[] ToGSBinary(this IEnumerable<int> value); public static byte[] ToGSBinary(this long value); public static byte[] ToGSBinary(this IEnumerable<long> value); public static byte[] ToGSBinary(this float value); public static byte[] ToGSBinary(this IEnumerable<float> value); public static byte[] ToGSBinary(this double value); public static byte[] ToGSBinary(this IEnumerable<double> value); public static byte[] ToGSBinary(this string value); public static byte[] ToGSBinary(this IEnumerable<string> value); public static string GetHexDump(this IEnumerable<byte> value); } Program.cs Here's the the object that I'm converting to binary in a loop. class Program { static void Main(string[] args) { GSObject obj = new GSObject(); obj.AttachShort("smallInt", 15); obj.AttachInt("medInt", 120700); obj.AttachLong("bigInt", 10900800700); obj.AttachDouble("doubleVal", Math.PI); obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" }); GSObject apple = new GSObject(); apple.AttachString("name", "Apple"); apple.AttachString("color", "red"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.5); GSObject lemon = new GSObject(); apple.AttachString("name", "Lemon"); apple.AttachString("color", "yellow"); apple.AttachBool("inStock", false); apple.AttachFloat("price", (float)0.8); GSObject apricoat = new GSObject(); apple.AttachString("name", "Apricoat"); apple.AttachString("color", "orange"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.9); GSObject kiwi = new GSObject(); apple.AttachString("name", "Kiwi"); apple.AttachString("color", "green"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)2.3); GSArray fruits = new GSArray(); fruits.AddGSObject(apple); fruits.AddGSObject(lemon); fruits.AddGSObject(apricoat); fruits.AddGSObject(kiwi); obj.AttachGSArray("fruits", fruits); Stopwatch w1 = Stopwatch.StartNew(); for (int i = 0; i < 50000; i++) { byte[] b = obj.ToGSBinary(); } w1.Stop(); Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian"); Console.WriteLine(w1.ElapsedMilliseconds + "ms"); } Here's the code for some of my other classes that are used in the code above. Most of it is repetitive. GSObject GSArray GSWrappedObject

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  • Getting a NullPointerException at seemingly random intervals, not sure why

    - by Miles
    I'm running an example from a Kinect library for Processing (http://www.shiffman.net/2010/11/14/kinect-and-processing/) and sometimes get a NullPointerException pointing to this line: int rawDepth = depth[offset]; The depth array is created in this line: int[] depth = kinect.getRawDepth(); I'm not exactly sure what a NullPointerException is, and much googling hasn't really helped. It seems odd to me that the code compiles 70% of the time and returns the error unpredictably. Could the hardware itself be affecting it? Here's the whole example if it helps: // Daniel Shiffman // Kinect Point Cloud example // http://www.shiffman.net // https://github.com/shiffman/libfreenect/tree/master/wrappers/java/processing import org.openkinect.*; import org.openkinect.processing.*; // Kinect Library object Kinect kinect; float a = 0; // Size of kinect image int w = 640; int h = 480; // We'll use a lookup table so that we don't have to repeat the math over and over float[] depthLookUp = new float[2048]; void setup() { size(800,600,P3D); kinect = new Kinect(this); kinect.start(); kinect.enableDepth(true); // We don't need the grayscale image in this example // so this makes it more efficient kinect.processDepthImage(false); // Lookup table for all possible depth values (0 - 2047) for (int i = 0; i < depthLookUp.length; i++) { depthLookUp[i] = rawDepthToMeters(i); } } void draw() { background(0); fill(255); textMode(SCREEN); text("Kinect FR: " + (int)kinect.getDepthFPS() + "\nProcessing FR: " + (int)frameRate,10,16); // Get the raw depth as array of integers int[] depth = kinect.getRawDepth(); // We're just going to calculate and draw every 4th pixel (equivalent of 160x120) int skip = 4; // Translate and rotate translate(width/2,height/2,-50); rotateY(a); for(int x=0; x<w; x+=skip) { for(int y=0; y<h; y+=skip) { int offset = x+y*w; // Convert kinect data to world xyz coordinate int rawDepth = depth[offset]; PVector v = depthToWorld(x,y,rawDepth); stroke(255); pushMatrix(); // Scale up by 200 float factor = 200; translate(v.x*factor,v.y*factor,factor-v.z*factor); // Draw a point point(0,0); popMatrix(); } } // Rotate a += 0.015f; } // These functions come from: http://graphics.stanford.edu/~mdfisher/Kinect.html float rawDepthToMeters(int depthValue) { if (depthValue < 2047) { return (float)(1.0 / ((double)(depthValue) * -0.0030711016 + 3.3309495161)); } return 0.0f; } PVector depthToWorld(int x, int y, int depthValue) { final double fx_d = 1.0 / 5.9421434211923247e+02; final double fy_d = 1.0 / 5.9104053696870778e+02; final double cx_d = 3.3930780975300314e+02; final double cy_d = 2.4273913761751615e+02; PVector result = new PVector(); double depth = depthLookUp[depthValue];//rawDepthToMeters(depthValue); result.x = (float)((x - cx_d) * depth * fx_d); result.y = (float)((y - cy_d) * depth * fy_d); result.z = (float)(depth); return result; } void stop() { kinect.quit(); super.stop(); } And here are the errors: processing.app.debug.RunnerException: NullPointerException at processing.app.Sketch.placeException(Sketch.java:1543) at processing.app.debug.Runner.findException(Runner.java:583) at processing.app.debug.Runner.reportException(Runner.java:558) at processing.app.debug.Runner.exception(Runner.java:498) at processing.app.debug.EventThread.exceptionEvent(EventThread.java:367) at processing.app.debug.EventThread.handleEvent(EventThread.java:255) at processing.app.debug.EventThread.run(EventThread.java:89) Exception in thread "Animation Thread" java.lang.NullPointerException at org.openkinect.processing.Kinect.enableDepth(Kinect.java:70) at PointCloud.setup(PointCloud.java:48) at processing.core.PApplet.handleDraw(PApplet.java:1583) at processing.core.PApplet.run(PApplet.java:1503) at java.lang.Thread.run(Thread.java:637)

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  • Confusion testing fftw3 - poisson equation 2d test

    - by user3699736
    I am having trouble explaining/understanding the following phenomenon: To test fftw3 i am using the 2d poisson test case: laplacian(f(x,y)) = - g(x,y) with periodic boundary conditions. After applying the fourier transform to the equation we obtain : F(kx,ky) = G(kx,ky) /(kx² + ky²) (1) if i take g(x,y) = sin (x) + sin(y) , (x,y) \in [0,2 \pi] i have immediately f(x,y) = g(x,y) which is what i am trying to obtain with the fft : i compute G from g with a forward Fourier transform From this i can compute the Fourier transform of f with (1). Finally, i compute f with the backward Fourier transform (without forgetting to normalize by 1/(nx*ny)). In practice, the results are pretty bad? (For instance, the amplitude for N = 256 is twice the amplitude obtained with N = 512) Even worse, if i try g(x,y) = sin(x)*sin(y) , the curve has not even the same form of the solution. (note that i must change the equation; i divide by two the laplacian in this case : (1) becomes F(kx,ky) = 2*G(kx,ky)/(kx²+ky²) Here is the code: /* * fftw test -- double precision */ #include <iostream> #include <stdio.h> #include <stdlib.h> #include <math.h> #include <fftw3.h> using namespace std; int main() { int N = 128; int i, j ; double pi = 3.14159265359; double *X, *Y ; X = (double*) malloc(N*sizeof(double)); Y = (double*) malloc(N*sizeof(double)); fftw_complex *out1, *in2, *out2, *in1; fftw_plan p1, p2; double L = 2.*pi; double dx = L/((N - 1)*1.0); in1 = (fftw_complex*) fftw_malloc(sizeof(fftw_complex)*(N*N) ); out2 = (fftw_complex*) fftw_malloc(sizeof(fftw_complex)*(N*N) ); out1 = (fftw_complex*) fftw_malloc(sizeof(fftw_complex)*(N*N) ); in2 = (fftw_complex*) fftw_malloc(sizeof(fftw_complex)*(N*N) ); p1 = fftw_plan_dft_2d(N, N, in1, out1, FFTW_FORWARD,FFTW_MEASURE ); p2 = fftw_plan_dft_2d(N, N, in2, out2, FFTW_BACKWARD,FFTW_MEASURE); for(i = 0; i < N; i++){ X[i] = -pi + (i*1.0)*2.*pi/((N - 1)*1.0) ; for(j = 0; j < N; j++){ Y[j] = -pi + (j*1.0)*2.*pi/((N - 1)*1.0) ; in1[i*N + j][0] = sin(X[i]) + sin(Y[j]) ; // row major ordering //in1[i*N + j][0] = sin(X[i]) * sin(Y[j]) ; // 2nd test case in1[i*N + j][1] = 0 ; } } fftw_execute(p1); // FFT forward for ( i = 0; i < N; i++){ // f = g / ( kx² + ky² ) for( j = 0; j < N; j++){ in2[i*N + j][0] = out1[i*N + j][0]/ (i*i+j*j+1e-16); in2[i*N + j][1] = out1[i*N + j][1]/ (i*i+j*j+1e-16); //in2[i*N + j][0] = 2*out1[i*N + j][0]/ (i*i+j*j+1e-16); // 2nd test case //in2[i*N + j][1] = 2*out1[i*N + j][1]/ (i*i+j*j+1e-16); } } fftw_execute(p2); //FFT backward // checking the results computed double erl1 = 0.; for ( i = 0; i < N; i++) { for( j = 0; j < N; j++){ erl1 += fabs( in1[i*N + j][0] - out2[i*N + j][0]/N/N )*dx*dx; cout<< i <<" "<< j<<" "<< sin(X[i])+sin(Y[j])<<" "<< out2[i*N+j][0]/N/N <<" "<< endl; // > output } } cout<< erl1 << endl ; // L1 error fftw_destroy_plan(p1); fftw_destroy_plan(p2); fftw_free(out1); fftw_free(out2); fftw_free(in1); fftw_free(in2); return 0; } I can't find any (more) mistakes in my code (i installed the fftw3 library last week) and i don't see a problem with the maths either but i don't think it's the fft's fault. Hence my predicament. I am all out of ideas and all out of google as well. Any help solving this puzzle would be greatly appreciated. note : compiling : g++ test.cpp -lfftw3 -lm executing : ./a.out output and i use gnuplot in order to plot the curves : (in gnuplot ) splot "output" u 1:2:4 ( for the computed solution )

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  • Problem measuring N times the execution time of a code block

    - by Nazgulled
    EDIT: I just found my problem after writing this long post explaining every little detail... If someone can give me a good answer on what I'm doing wrong and how can I get the execution time in seconds (using a float with 5 decimal places or so), I'll mark that as accepted. Hint: The problem was on how I interpreted the clock_getttime() man page. Hi, Let's say I have a function named myOperation that I need to measure the execution time of. To measure it, I'm using clock_gettime() as it was recommend here in one of the comments. My teacher recommends us to measure it N times so we can get an average, standard deviation and median for the final report. He also recommends us to execute myOperation M times instead of just one. If myOperation is a very fast operation, measuring it M times allow us to get a sense of the "real time" it takes; cause the clock being used might not have the required precision to measure such operation. So, execution myOperation only one time or M times really depends if the operation itself takes long enough for the clock precision we are using. I'm having trouble dealing with that M times execution. Increasing M decreases (a lot) the final average value. Which doesn't make sense to me. It's like this, on average you take 3 to 5 seconds to travel from point A to B. But then you go from A to B and back to A 5 times (which makes it 10 times, cause A to B is the same as B to A) and you measure that. Than you divide by 10, the average you get is supposed to be the same average you take traveling from point A to B, which is 3 to 5 seconds. This is what I want my code to do, but it's not working. If I keep increasing the number of times I go from A to B and back A, the average will be lower and lower each time, it makes no sense to me. Enough theory, here's my code: #include <stdio.h> #include <time.h> #define MEASUREMENTS 1 #define OPERATIONS 1 typedef struct timespec TimeClock; TimeClock diffTimeClock(TimeClock start, TimeClock end) { TimeClock aux; if((end.tv_nsec - start.tv_nsec) < 0) { aux.tv_sec = end.tv_sec - start.tv_sec - 1; aux.tv_nsec = 1E9 + end.tv_nsec - start.tv_nsec; } else { aux.tv_sec = end.tv_sec - start.tv_sec; aux.tv_nsec = end.tv_nsec - start.tv_nsec; } return aux; } int main(void) { TimeClock sTime, eTime, dTime; int i, j; for(i = 0; i < MEASUREMENTS; i++) { printf(" » MEASURE %02d\n", i+1); clock_gettime(CLOCK_REALTIME, &sTime); for(j = 0; j < OPERATIONS; j++) { myOperation(); } clock_gettime(CLOCK_REALTIME, &eTime); dTime = diffTimeClock(sTime, eTime); printf(" - NSEC (TOTAL): %ld\n", dTime.tv_nsec); printf(" - NSEC (OP): %ld\n\n", dTime.tv_nsec / OPERATIONS); } return 0; } Notes: The above diffTimeClock function is from this blog post. I replaced my real operation with myOperation() because it doesn't make any sense to post my real functions as I would have to post long blocks of code, you can easily code a myOperation() with whatever you like to compile the code if you wish. As you can see, OPERATIONS = 1 and the results are: » MEASURE 01 - NSEC (TOTAL): 27456580 - NSEC (OP): 27456580 For OPERATIONS = 100 the results are: » MEASURE 01 - NSEC (TOTAL): 218929736 - NSEC (OP): 2189297 For OPERATIONS = 1000 the results are: » MEASURE 01 - NSEC (TOTAL): 862834890 - NSEC (OP): 862834 For OPERATIONS = 10000 the results are: » MEASURE 01 - NSEC (TOTAL): 574133641 - NSEC (OP): 57413 Now, I'm not a math wiz, far from it actually, but this doesn't make any sense to me whatsoever. I've already talked about this with a friend that's on this project with me and he also can't understand the differences. I don't understand why the value is getting lower and lower when I increase OPERATIONS. The operation itself should take the same time (on average of course, not the exact same time), no matter how many times I execute it. You could tell me that that actually depends on the operation itself, the data being read and that some data could already be in the cache and bla bla, but I don't think that's the problem. In my case, myOperation is reading 5000 lines of text from an CSV file, separating the values by ; and inserting those values into a data structure. For each iteration, I'm destroying the data structure and initializing it again. Now that I think of it, I also that think that there's a problem measuring time with clock_gettime(), maybe I'm not using it right. I mean, look at the last example, where OPERATIONS = 10000. The total time it took was 574133641ns, which would be roughly 0,5s; that's impossible, it took a couple of minutes as I couldn't stand looking at the screen waiting and went to eat something.

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  • VPN still working after rebooting without client - DrayTek client shows "No Connection"

    - by HeavenCore
    My home network is a simple router + pc's setup, nothing fancy - the router has DHCP enabled for 192.168.0.X (255.255.255.0) and my PC picks up the address 192.168.0.82. There are no devices on my local lan in the 192.168.1.x range. On my pc i have the DrayTek VPN client, and a company i do some work for has a DrayTek Vigor router. The VPN client establishes a VPN to that remote company using an IPSec Tunnel (PreShared Key - no encryption) Last night i shut down my pc with the VPN tunnel still connected, when i turned my computer on this morning i accidentally clicked an RDP shortcut to 192.168.1.2 (a host in the remote company) and to my amazement it connected?!? I checked and the DrayTek VPN client isnt running, and when i did run it, it clearly shows "Status: No connection". confused as to how my machine can still talk to this remote machine i tried a trace: C:\Users\HeavenCore>tracert 192.168.1.2 Tracing route to C4SERVERII [192.168.1.2] over a maximum of 30 hops: 1 * * * Request timed out. 2 * * * Request timed out. 3 * * * Request timed out. 4 * * * Request timed out. 5 * * * Request timed out. 6 * * * Request timed out. 7 * * * Request timed out. 8 * * * Request timed out. 9 * * * Request timed out. 10 * * * Request timed out. 11 * * * Request timed out. 12 15 ms 21 ms 32 ms C4SERVERII [192.168.1.2] Trace complete. No indication there as to how it's getting from my network to the remote host. with my network mask being 255.255.255.0 with ip 192.168.0.1 i dont even see how packets are routing to 192.168.1.1 - unless there was a static route in place, so i checked the route table: IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.82 266 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 192.168.0.0 255.255.255.0 On-link 192.168.0.82 266 192.168.0.82 255.255.255.255 On-link 192.168.0.82 266 192.168.0.255 255.255.255.255 On-link 192.168.0.82 266 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 192.168.0.82 266 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 192.168.0.82 266 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 0.0.0.0 0.0.0.0 192.168.0.1 Default =========================================================================== As far as i can see, nothing indicating how my packets are getting to 192.168.1.2??? To confirm i was on a different subnet i did an ipconfig /all: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Marvell Yukon 88E8056 PCI-E Gigabit Ether net Controller Physical Address. . . . . . . . . : 00-23-54-F3-4E-BA DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.0.82(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.0.1 DNS Servers . . . . . . . . . . . : 192.168.0.1 208.67.222.222 NetBIOS over Tcpip. . . . . . . . : Enabled Yet straight after confirming my ip and subnet as above i can go ahead and ping the remote machine: C:\Users\HeavenCore>ping 192.168.1.2 Pinging 192.168.1.2 with 32 bytes of data: Reply from 192.168.1.2: bytes=32 time=48ms TTL=127 Reply from 192.168.1.2: bytes=32 time=23ms TTL=127 Reply from 192.168.1.2: bytes=32 time=103ms TTL=127 Reply from 192.168.1.2: bytes=32 time=25ms TTL=127 Ping statistics for 192.168.1.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 23ms, Maximum = 103ms, Average = 49ms Also, note on the ping how the times are 35ms ish, this clearly shows the pings are to the remote host and not something on my local lan (all stuff on my local lan pings in 0ms) - plus i verified the host was actually the host via RDP. My Question: Can an IPSec tunnel stay up some how after a reboot without use of the VPN client? (well, i can clearly see that it can) - where in windows is there visibility of this? how does my machine know where to route the packets? I appreciate any insights & thoughts!

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  • Graphics glitch when drawing to a Cairo context obtained from a gtk.DrawingArea inside a gtk.Viewport.

    - by user410023
    I am trying to redraw the part of the DrawingArea that is visible in the Viewport in the expose-event handler. However, it seems that I am doing something wrong with the coordinates that are passed to the event handler because there is garbage at the edge of the Viewport when scrolling. Can anyone tell what I am doing wrong? Here is a small example: import pygtk pygtk.require("2.0") import gtk from numpy import array from math import pi class Circle(object): def init(self, position = [0., 0.], radius = 0., edge = (0., 0., 0.), fill = None): self.position = position self.radius = radius self.edge = edge self.fill = fill def draw(self, ctx): rect = array(ctx.clip_extents()) rect[2] -= rect[0] rect[3] -= rect[1] center = rect[2:4] / 2 ctx.arc(center[0], center[1], self.radius, 0., 2. * pi) if self.fill != None: ctx.set_source_rgb(*self.fill) ctx.fill_preserve() ctx.set_source_rgb(*self.edge) ctx.stroke() class Scene(object): class Proxy(object): directory = {} def init(self, target, layers = set()): self.target = target self.layers = layers Scene.Proxy.directory[target] = self def __init__(self, viewport): self.objects = {} self.layers = [set()] self.viewport = viewport self.signals = {} def draw(self, ctx): x = self.viewport.get_hadjustment().value y = self.viewport.get_vadjustment().value ctx.set_source_rgb(1., 1., 1.) ctx.paint() ctx.translate(x, y) for obj in self: obj.draw(ctx) def add(self, item, layer = 0): item = Scene.Proxy(item, layers = set((layer,))) assert(hasattr(item.target, "draw")) assert(isinstance(layer, int)) item.layers.add(layer) while not layer < len(self.layers): self.layers.append(set()) self.layers[layer].add(item) if not item in self.objects: self.objects[item] = set() self.objects[item].add(layer) def remove(self, item, layers = None): item = Scene.Proxy.directory[item] if layers == None: layers = self.objects[item] for layer in layers: layer.remove(item) item.layers.remove(layer) if len(item.layers) == 0: self.objects.remove(item) def __iter__(self): for layer in self.layers: for item in layer: yield item.target class App(object): def init(self): signals = { "canvas_exposed": self.update_canvas, "gtk_main_quit": gtk.main_quit } self.builder = gtk.Builder() self.builder.add_from_file("graphics_glitch.glade") self.window = self.builder.get_object("window") self.viewport = self.builder.get_object("viewport") self.canvas = self.builder.get_object("canvas") self.scene = Scene(self.viewport) signals.update(self.scene.signals) self.builder.connect_signals(signals) self.window.show() def update_canvas(self, widget, event): ctx = self.canvas.window.cairo_create() self.scene.draw(ctx) ctx.clip() if name == "main": app = App() scene = app.scene scene.add(Circle((0., 0.), 10.)) gtk.main() And the Glade file "graphics_glitch.glade": <?xml version="1.0"?> <interface> <requires lib="gtk+" version="2.16"/> <!-- interface-naming-policy project-wide --> <object class="GtkWindow" id="window"> <property name="width_request">200</property> <property name="height_request">200</property> <property name="visible">True</property> <signal name="destroy" handler="gtk_main_quit"/> <child> <object class="GtkScrolledWindow" id="scrolledwindow1"> <property name="visible">True</property> <property name="can_focus">True</property> <property name="hadjustment">h_adjust</property> <property name="vadjustment">v_adjust</property> <property name="hscrollbar_policy">automatic</property> <property name="vscrollbar_policy">automatic</property> <child> <object class="GtkViewport" id="viewport"> <property name="visible">True</property> <property name="resize_mode">queue</property> <child> <object class="GtkDrawingArea" id="canvas"> <property name="width_request">640</property> <property name="height_request">480</property> <property name="visible">True</property> <signal name="expose_event" handler="canvas_exposed"/> </object> </child> </object> </child> </object> </child> </object> <object class="GtkAdjustment" id="h_adjust"> <property name="lower">-1000</property> <property name="upper">1000</property> <property name="step_increment">1</property> <property name="page_increment">25</property> <property name="page_size">25</property> </object> <object class="GtkAdjustment" id="v_adjust"> <property name="lower">-1000</property> <property name="upper">1000</property> <property name="step_increment">1</property> <property name="page_increment">25</property> <property name="page_size">25</property> </object> </interface> Thanks! --Dan

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  • Subset sum problem

    - by MadBoy
    I'm having a problem with counting which is continuation of this question. I am not really a math person so it's really hard for me to figure out this subset sum problem which was suggested as resolution. I'm having 4 ArrayList in which I hold data: alId, alTransaction, alNumber, alPrice Type | Transaction | Number | Price 8 | Buy | 95.00000000 | 305.00000000 8 | Buy | 126.00000000 | 305.00000000 8 | Buy | 93.00000000 | 306.00000000 8 | Transfer out | 221.00000000 | 305.00000000 8 | Transfer in | 221.00000000 | 305.00000000 8 | Sell | 93.00000000 | 360.00000000 8 | Sell | 95.00000000 | 360.00000000 8 | Sell | 126.00000000 | 360.00000000 8 | Buy | 276.00000000 | 380.00000000 In the end I'm trying to get what's left for customer and what's left I put into 3 array lists: alNew (corresponds to alNumber), alNewPoIle (corresponds to alPrice), and alNewCo (corrseponds to alID) ArrayList alNew = new ArrayList(); ArrayList alNewPoIle = new ArrayList(); ArrayList alNewCo = new ArrayList(); for (int i = 0; i < alTransaction.Count; i++) { string tempAkcjeCzynnosc = (string) alTransaction[i]; string tempAkcjeInId = (string) alID[i]; decimal varAkcjeCena = (decimal) alPrice[i]; decimal varAkcjeIlosc = (decimal) alNumber[i]; int index; switch (tempAkcjeCzynnosc) { case "Transfer out": case "Sell": index = alNew.IndexOf(varAkcjeIlosc); if (index != -1) { alNew.RemoveAt(index); alNewPoIle.RemoveAt(index); alNewCo.RemoveAt(index); } else { ArrayList alTemp = new ArrayList(); decimal varAkcjeSuma = 0; for (int j = 0; j < alNew.Count; j ++) { string akcjeInId = (string) alNewCo[j]; decimal akcjeCena = (decimal) alNewPoIle[j]; decimal akcjeIlosc = (decimal) alNew[j]; if (tempAkcjeInId == akcjeInId && akcjeCena == varAkcjeCena) { alTemp.Add(j); varAkcjeSuma = varAkcjeSuma + akcjeIlosc; } } if (varAkcjeSuma == varAkcjeIlosc) { for (int j = alTemp.Count -1 ; j >=0 ; j --) { int tempIndex = (int) alTemp[j]; alNew.RemoveAt(tempIndex); alNewPoIle.RemoveAt(tempIndex); alNewCo.RemoveAt(tempIndex); } } } break; case "Transfer In": case "Buy": alNew.Add(varAkcjeIlosc); alNewPoIle.Add(varAkcjeCena); alNewCo.Add(tempAkcjeInId); break; } } Basically I'm adding and removing things from Array depending on Transaction Type, Transaction ID and Numbers. I'm adding numbers to ArrayList like 156, 340 (when it is TransferIn or Buy) etc and then i remove them doing it like 156, 340 (when it's TransferOut, Sell). My solution works for that without a problem. The problem I have is that for some old data employees were entering sum's like 1500 instead of 500+400+100+500. How would I change it so that when there's Sell/TransferOut or Buy/Transfer In and there's no match inside ArrayList it should try to add multiple items from thatArrayList and find elements that combine into aggregate. Inside my code I tried to resolve that problem with simple summing everything when there's no match (index == 1) if (index != -1) { alNew.RemoveAt(index); alNewPoIle.RemoveAt(index); alNewCo.RemoveAt(index); } else { ArrayList alTemp = new ArrayList(); decimal varAkcjeSuma = 0; for (int j = 0; j < alNew.Count; j ++) { string akcjeInId = (string) alNewCo[j]; decimal akcjeCena = (decimal) alNewPoIle[j]; decimal akcjeIlosc = (decimal) alNew[j]; if (tempAkcjeInId == akcjeInId && akcjeCena == varAkcjeCena) { alTemp.Add(j); varAkcjeSuma = varAkcjeSuma + akcjeIlosc; } } if (varAkcjeSuma == varAkcjeIlosc) { for (int j = alTemp.Count -1 ; j >=0 ; j --) { int tempIndex = (int) alTemp[j]; alNew.RemoveAt(tempIndex); alNewPoIle.RemoveAt(tempIndex); alNewCo.RemoveAt(tempIndex); } } But it only works if certain conditions are met, and fails for the rest.

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  • PHP Fatal error, trying to request method inside model multiple times

    - by Tom
    The error message [23-Mar-2010 08:36:16] PHP Fatal error: Cannot redeclare humanize() (previously declared in /Users/tmclssns/Sites/nadar/nadar/trunk/webapp/application/filer/models/Filer/Aggregate.php:133) in /Users/tmclssns/Sites/nadar/nadar/trunk/webapp/application/filer/models/Filer/Aggregate.php on line 133 I have a "Filer" model which contains several methods to generate graphs. Each method in there related to generating graphs has the suffix "Graph" in the method name. As we have some performance issues, I try to render the graphs in advance (using cron) instead of rendering them on each request. The code below is what I came up with: public function generategraphsAction() { $this->_helper->viewRenderer->setNoRender(); $config = Zend_Registry::get('config'); $id = $this->_getParam('filerid'); $filer = new Filer($id); $filer_methods = get_class_methods($filer); foreach ($filer_methods as $filer_method) { if (preg_match('/^(.*)Graph$/i', $filer_method, $matches)) { $path = $config->imaging_caching_dir . "/$id/{$matches[1]}.png"; $filer->$matches[0]($path); } } // var_dump(get_class_methods($filer)); die; } The result from the var_dump(), when uncommented, is: array 0 => string '__construct' (length=11) 1 => string 'find_by_name' (length=12) 2 => string 'getPartner' (length=10) 3 => string 'getSlots' (length=8) 4 => string 'getGroups' (length=9) 5 => string 'grouplist' (length=9) 6 => string 'getAggregates' (length=13) 7 => string 'getVolumes' (length=10) 8 => string 'getAggregateVolumes' (length=19) 9 => string 'getShelves' (length=10) 10 => string 'getAutoSupportHistory' (length=21) 11 => string 'getAutoSupportMail' (length=18) 12 => string 'getOrphans' (length=10) 13 => string 'getAll' (length=6) 14 => string 'getDiskRevOverview' (length=18) 15 => string 'getDiskTypeOverview' (length=19) 16 => string 'getDiskTypeSizeFunctionOverview' (length=31) 17 => string 'getLicenses' (length=11) 18 => string 'removeGroup' (length=11) 19 => string 'addGroup' (length=8) 20 => string 'hasGroup' (length=8) 21 => string 'aggdefaultGraph' (length=15) 22 => string 'aggbarGraph' (length=11) 23 => string 'voldefaultGraph' (length=15) 24 => string 'volbarGraph' (length=11) 25 => string 'replicationGraph' (length=16) 26 => string 'getReplicationData' (length=18) 27 => string 'humanize' (length=8) 28 => string 'getFiler' (length=8) 29 => string 'getOptions' (length=10) 30 => string 'getCifsInfo' (length=11) 31 => string 'getCifsStats' (length=12) 32 => string '__get' (length=5) 33 => string 'tr' (length=2) 34 => string 'trs' (length=3) 35 => string 'fieldList' (length=9) The generategraphsAction() method finds the 'Graph' methods correctly: array 0 => string 'aggdefaultGraph' (length=15) 1 => string 'aggdefault' (length=10) array 0 => string 'aggbarGraph' (length=11) 1 => string 'aggbar' (length=6) array 0 => string 'voldefaultGraph' (length=15) 1 => string 'voldefault' (length=10) array 0 => string 'volbarGraph' (length=11) 1 => string 'volbar' (length=6) array 0 => string 'replicationGraph' (length=16) 1 => string 'replication' (length=11) However when the first graph is generated, it generates the above listed PHP fatal error. Anyone can come up with a solution to this? I tried to pass by reference or switch a few things around (like re declare the Filer model, $current_filer = new Filer($id); and unset() it again after the request, but resulted in the same error) without much success. The referenced method "humanize" isn't used for anything I'm doing at the moment, but belongs to the Model because it's used in several other places. Of course, removing the method is not really an option right now, and the model contains several other methods as well so I assume if I just move the humanize method around, it will generate an error on the next one. For reference, the humanize() method: public function humanize ($kbytes, $unit = null) { // KiloByte, Megabyte, GigaByte, TeraByte, PetaByte, ExaByte, ZettaByte, YottaByte $units = array('KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'); if (null !== $units) { $i = array_search(substr($unit, -2), $units); if (! $i) { $i = floor((strlen($kbytes) - 1) / 3); } } else { $i = floor((strlen($kbytes) - 1) / 3); } $newSize = round($kbytes / pow(1024, $i), 2); return $newSize . $units[$i]; } Thanks in advance for the help offered.

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  • How do implement a breadth first traversal?

    - by not looking for answer
    //This is what I have. I thought pre-order was the same and mixed it up with depth first! import java.util.LinkedList; import java.util.Queue; public class Exercise25_1 { public static void main(String[] args) { BinaryTree tree = new BinaryTree(new Integer[] {10, 5, 15, 12, 4, 8 }); System.out.print("\nInorder: "); tree.inorder(); System.out.print("\nPreorder: "); tree.preorder(); System.out.print("\nPostorder: "); tree.postorder(); //call the breadth method to test it System.out.print("\nBreadthFirst:"); tree.breadth(); } } class BinaryTree { private TreeNode root; /** Create a default binary tree */ public BinaryTree() { } /** Create a binary tree from an array of objects */ public BinaryTree(Object[] objects) { for (int i = 0; i < objects.length; i++) { insert(objects[i]); } } /** Search element o in this binary tree */ public boolean search(Object o) { return search(o, root); } public boolean search(Object o, TreeNode root) { if (root == null) { return false; } if (root.element.equals(o)) { return true; } else { return search(o, root.left) || search(o, root.right); } } /** Return the number of nodes in this binary tree */ public int size() { return size(root); } public int size(TreeNode root) { if (root == null) { return 0; } else { return 1 + size(root.left) + size(root.right); } } /** Return the depth of this binary tree. Depth is the * number of the nodes in the longest path of the tree */ public int depth() { return depth(root); } public int depth(TreeNode root) { if (root == null) { return 0; } else { return 1 + Math.max(depth(root.left), depth(root.right)); } } /** Insert element o into the binary tree * Return true if the element is inserted successfully */ public boolean insert(Object o) { if (root == null) { root = new TreeNode(o); // Create a new root } else { // Locate the parent node TreeNode parent = null; TreeNode current = root; while (current != null) { if (((Comparable)o).compareTo(current.element) < 0) { parent = current; current = current.left; } else if (((Comparable)o).compareTo(current.element) > 0) { parent = current; current = current.right; } else { return false; // Duplicate node not inserted } } // Create the new node and attach it to the parent node if (((Comparable)o).compareTo(parent.element) < 0) { parent.left = new TreeNode(o); } else { parent.right = new TreeNode(o); } } return true; // Element inserted } public void breadth() { breadth(root); } // Implement this method to produce a breadth first // search traversal public void breadth(TreeNode root){ if (root == null) return; System.out.print(root.element + " "); breadth(root.left); breadth(root.right); } /** Inorder traversal */ public void inorder() { inorder(root); } /** Inorder traversal from a subtree */ private void inorder(TreeNode root) { if (root == null) { return; } inorder(root.left); System.out.print(root.element + " "); inorder(root.right); } /** Postorder traversal */ public void postorder() { postorder(root); } /** Postorder traversal from a subtree */ private void postorder(TreeNode root) { if (root == null) { return; } postorder(root.left); postorder(root.right); System.out.print(root.element + " "); } /** Preorder traversal */ public void preorder() { preorder(root); } /** Preorder traversal from a subtree */ private void preorder(TreeNode root) { if (root == null) { return; } System.out.print(root.element + " "); preorder(root.left); preorder(root.right); } /** Inner class tree node */ private class TreeNode { Object element; TreeNode left; TreeNode right; public TreeNode(Object o) { element = o; } } }

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  • c++ and c# speed compared

    - by Mack
    I was worried about C#'s speed when it deals with heavy calculations, when you need to use raw CPU power. I always thought that C++ is much faster than C# when it comes to calculations. So I did some quick tests. The first test computes prime numbers < an integer n, the second test computes some pandigital numbers. The idea for second test comes from here: Pandigital Numbers C# prime computation: using System; using System.Diagnostics; class Program { static int primes(int n) { uint i, j; int countprimes = 0; for (i = 1; i <= n; i++) { bool isprime = true; for (j = 2; j <= Math.Sqrt(i); j++) if ((i % j) == 0) { isprime = false; break; } if (isprime) countprimes++; } return countprimes; } static void Main(string[] args) { int n = int.Parse(Console.ReadLine()); Stopwatch sw = new Stopwatch(); sw.Start(); int res = primes(n); sw.Stop(); Console.WriteLine("I found {0} prime numbers between 0 and {1} in {2} msecs.", res, n, sw.ElapsedMilliseconds); Console.ReadKey(); } } C++ variant: #include <iostream> #include <ctime> int primes(unsigned long n) { unsigned long i, j; int countprimes = 0; for(i = 1; i <= n; i++) { int isprime = 1; for(j = 2; j < (i^(1/2)); j++) if(!(i%j)) { isprime = 0; break; } countprimes+= isprime; } return countprimes; } int main() { int n, res; cin>>n; unsigned int start = clock(); res = primes(n); int tprime = clock() - start; cout<<"\nI found "<<res<<" prime numbers between 1 and "<<n<<" in "<<tprime<<" msecs."; return 0; } When I ran the test trying to find primes < than 100,000, C# variant finished in 0.409 seconds and C++ variant in 5.553 seconds. When I ran them for 1,000,000 C# finished in 6.039 seconds and C++ in about 337 seconds. Pandigital test in C#: using System; using System.Diagnostics; class Program { static bool IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return false; } return digits == (1 << count) - 1; } static void Main() { int pans = 0; Stopwatch sw = new Stopwatch(); sw.Start(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } sw.Stop(); Console.WriteLine("{0}pcs, {1}ms", pans, sw.ElapsedMilliseconds); Console.ReadKey(); } } Pandigital test in C++: #include <iostream> #include <ctime> using namespace std; int IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return 0; } return digits == (1 << count) - 1; } int main() { int pans = 0; unsigned int start = clock(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } int ptime = clock() - start; cout<<"\nPans:"<<pans<<" time:"<<ptime; return 0; } C# variant runs in 29.906 seconds and C++ in about 36.298 seconds. I didn't touch any compiler switches and bot C# and C++ programs were compiled with debug options. Before I attempted to run the test I was worried that C# will lag well behind C++, but now it seems that there is a pretty big speed difference in C# favor. Can anybody explain this? C# is jitted and C++ is compiled native so it's normal that a C++ will be faster than a C# variant. Thanks for the answers!

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  • How would you go about tackling this problem? [SOLVED in C++]

    - by incrediman
    Intro: EDIT: See solution at the bottom of this question (c++) I have a programming contest coming up in about half a week, and I've been prepping :) I found a bunch of questions from this canadian competition, they're great practice: http://cemc.math.uwaterloo.ca/contests/computing/2009/stage2/day1.pdf I'm looking at problem B ("Dinner"). Any idea where to start? I can't really think of anything besides the naive approach (ie. trying all permutations) which would take too long to be a valid answer. Btw, the language there says c++ and pascal I think, but i don't care what language you use - I mean really all I want is a hint as to the direction I should proceed in, and perhpas a short explanation to go along with it. It feels like I'm missing something obvious... Of course extended speculation is more than welcome, but I just wanted to clarify that I'm not looking for a full solution here :) Short version of the question: You have a binary string N of length 1-100 (in the question they use H's and G's instead of one's and 0's). You must remove all of the digits from it, in the least number of steps possible. In each step you may remove any number of adjacent digits so long as they are the same. That is, in each step you can remove any number of adjacent G's, or any number of adjacent H's, but you can't remove H's and G's in one step. Example: HHHGHHGHH Solution to the example: 1. HHGGHH (remove middle Hs) 2. HHHH (remove middle Gs) 3. Done (remove Hs) -->Would return '3' as the answer. Note that there can also be a limit placed on how large adjacent groups have to be when you remove them. For example it might say '2', and then you can't remove single digits (you'd have to remove pairs or larger groups at a time). Solution I took Mark Harrison's main algorithm, and Paradigm's grouping idea and used them to create the solution below. You can try it out on the official test cases if you want. //B.cpp //include debug messages? #define DEBUG false #include <iostream> #include <stdio.h> #include <vector> using namespace std; #define FOR(i,n) for (int i=0;i<n;i++) #define FROM(i,s,n) for (int i=s;i<n;i++) #define H 'H' #define G 'G' class String{ public: int num; char type; String(){ type=H; num=0; } String(char type){ this->type=type; num=1; } }; //n is the number of bits originally in the line //k is the minimum number of people you can remove at a time //moves is the counter used to determine how many moves we've made so far int n, k, moves; int main(){ /*Input from File*/ scanf("%d %d",&n,&k); char * buffer = new char[200]; scanf("%s",buffer); /*Process input into a vector*/ //the 'line' is a vector of 'String's (essentially contigious groups of identical 'bits') vector<String> line; line.push_back(String()); FOR(i,n){ //if the last String is of the correct type, simply increment its count if (line.back().type==buffer[i]) line.back().num++; //if the last String is of the wrong type but has a 0 count, correct its type and set its count to 1 else if (line.back().num==0){ line.back().type=buffer[i]; line.back().num=1; } //otherwise this is the beginning of a new group, so create the new group at the back with the correct type, and a count of 1 else{ line.push_back(String(buffer[i])); } } /*Geedily remove groups until there are at most two groups left*/ moves=0; int I;//the position of the best group to remove int bestNum;//the size of the newly connected group the removal of group I will create while (line.size()>2){ /*START DEBUG*/ if (DEBUG){ cout<<"\n"<<moves<<"\n----\n"; FOR(i,line.size()) printf("%d %c \n",line[i].num,line[i].type); cout<<"----\n"; } /*END DEBUG*/ I=1; bestNum=-1; FROM(i,1,line.size()-1){ if (line[i-1].num+line[i+1].num>bestNum && line[i].num>=k){ bestNum=line[i-1].num+line[i+1].num; I=i; } } //remove the chosen group, thus merging the two adjacent groups line[I-1].num+=line[I+1].num; line.erase(line.begin()+I);line.erase(line.begin()+I); moves++; } /*START DEBUG*/ if (DEBUG){ cout<<"\n"<<moves<<"\n----\n"; FOR(i,line.size()) printf("%d %c \n",line[i].num,line[i].type); cout<<"----\n"; cout<<"\n\nFinal Answer: "; } /*END DEBUG*/ /*Attempt the removal of the last two groups, and output the final result*/ if (line.size()==2 && line[0].num>=k && line[1].num>=k) cout<<moves+2;//success else if (line.size()==1 && line[0].num>=k) cout<<moves+1;//success else cout<<-1;//not everyone could dine. /*START DEBUG*/ if (DEBUG){ cout<<" moves."; } /*END DEBUG*/ }

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  • Network throughput issue (ARP-related)

    - by Joel Coel
    The small college where I work is having some very strange network issues. I'm looking for any advice or ideas here. We were fine over the summer, but the trouble began few days after students returned to campus in force for the fall term. Symptoms The main symptom is that internet access will work, but it's very slow... often to the point of timeouts. As an example, a typical result from Speedtest.net will return .4Mbps download, but allow 3 to 8 Mbps upload speed. Lesser symptoms may include severely limited performance transferring data to and from our file server, or even in some cases the inability to log in to the computer (cannot reach the domain controller). The issue crosses multiple vlans, and has effected devices on nearly every vlan we operate. The issue does not impact all machines on the network. An unaffected machine will typically see at least 11Mbps download from speedtest.net, and perhaps much more depending on larger campus traffic patterns at the time. There is one variation on the larger issue. We have one vlan where users were unable to log into nearly all of the machines at all. IT staff would log in using a local administrator account (or in some cases cached credentials), and from there a release/renew or pinging the gateway would allow the machine to work... for a while. Complicating this issue is that this vlan covers our computer labs, which use software called Deep Freeze to completely reset the hard drives after a reboot. It could just the same issue manifesting differently because of stale data on machines that have not permanently altered low-level info for weeks. We were able to solve this, however, by creating a new vlan and moving the labs over to the new vlan wholesale. Instigations Eventually we noticed that the effected machines all had recent dhcp leases. We can predict when a machine will become "slow" by watching when a dhcp lease comes up for renewal. We played with setting the lease time very short for a test vlan, but all that did was remove our ability to predict when the machine would become slow. Machines with static IPs have pretty much always worked normally. Manually releasing/renewing an address will never cause a machine to become slow. In fact, in some cases this process has fixed a machine in that state. Most of the time, though, it doesn't help. We also noticed that mobile machines like laptops are likely to become slow when they cross to new vlans. Wireless on campus is divided up into "zones", where each zone maps to a small set of buildings. Moving to a new building can place you in a zone, thereby causing you to get a new address. A machine resuming from sleep mode is also very likely to be slow. Mitigations Sometimes, but not always, clearing the arp cache on an effected machine will allow it to work normally again. As already mentioned, releasing/renewing a local machine's IP address can fix that machine, but it's not guaranteed. Pinging the default gateway can also sometimes help with a slow machine. What seems to help most to mitigate the issue is clearing the arp cache on our core layer-3 switch. This switch is used for our dhcp system as the default gateway on all vlans, and it handles inter-vlan routing. The model is a 3Com 4900SX. To try to mitigate the issue, we have the cache timeout set on the switch all the way down to the lowest possible time, but it hasn't helped. I also put together a script that runs every few minutes to automatically connect to the switch and reset the cache. Unfortunately, this does not always work, and can even cause some machines to end up in the slow state for a short time (though these seem to correct themselves after a few minutes). We currently have a scheduled job that runs every 10 minutes to force the core switch to clear it's ARP cache, but this is far from perfect or desirable. Reproduction We now have a test machine that we can force into the slow state at will. It is connected to a switch with ports set up for each of our vlans. We make the machine slow by connecting to different vlans, and after a new connection or two it will be slow. It's also worth noting in this section that this has happened before at the start of prior terms, but in the past the problem has gone away on it's own after a few days. It solved itself before we had a chance to do much diagnostic work... hence why we've allowed it to drag so long into the term this time 'round; the expectation was this would be a short-lived situation. Other Factors It's worth mentioning that we have had about half a dozen switches just outright fail over the last year. These are mainly 2003/2004-era 3Coms (mostly 4200's) that were all put in at about the same time. They should still be covered under warranty, buy HP has made getting service somewhat difficult. Mostly in power supplies that have failed, but in a couple cases we have used a power supply from a switch with a failed mainboard to bring a switch with a failed power supply back to life. We do have UPS devices on all but three of four switches now, but that was not the case when I started two and a half years ago. Severe budget constraints (we were on the Dept. of Ed's financially challenged institutions list a couple years back) have forced me to look to the likes of Netgear and TrendNet for replacements, but so far these low-end models seem to be holding their own. It's also worth mentioning that the big change on our network this summer was migrating from a single cross-campus wireless SSID to the zoned approach mentioned earlier. I don't think this is the source of the issue, as like I've said: we've seen this before. However, it's possible this is exacerbating the issue, and may be much of the reason it's been so hard to isolate. Diagnosis At first it seemed clear to us, given the timing and persistent nature of the problem, that the source of the issue was an infected (or malicious) student machine doing ARP cache poisoning. However, repeated attempts to isolate the source have failed. Those attempts include numerous wireshark packet traces, and even taking entire buildings offline for brief periods. We have not been able even to find a smoking gun bad ARP entry. My current best guess is an overloaded or failing core switch, but I'm not sure on how to test for this, and the cost of replacing it blindly is steep. Again, any ideas appreciated.

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  • Javascript: selfmade methods not working correctly

    - by hdr
    Hi everyone, I tried to figure this out for some days now, I tried to use my own object to sort of replace the global object to reduce problems with other scripts (userscripts, chrome extensions... that kind of stuff). However I can't get things to work for some reason. I tried some debugging with JSLint, the developer tools included in Google Chrome, Firebug and the integrated schript debugger in IE8 but there is no error that explains why it doesn't work at all in any browser I tried. I tried IE 8, Google Chrome 10.0.612.3 dev, Firefox 3.6.13, Safari 5.0.3 and Opera 11. So... here is the code: HTML: <!DOCTYPE HTML> <html manifest="c.manifest"> <head> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <meta charset="utf-8"> <!--[if IE]> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/chrome-frame/1/CFInstall.min.js"></script> <script src="https://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE9.js">IE7_PNG_SUFFIX=".png";</script> <![endif]--> <!--[if lt IE 9]> <script src="js/lib/excanvas.js"></script> <script src="https://html5shiv.googlecode.com/svn/trunk/html5.js"></script> <![endif]--> <script src="js/data.js"></script> </head> <body> <div id="controls"> <button onclick="MYOBJECTis.next()">Next</button> </div> <div id="textfield"></div> <canvas id="game"></canvas> </body> </html> Javascript: var that = window, it = document, k = Math.floor; var MYOBJECTis = { aresizer: function(){ // This method looks like it doesn't work. // It should automatically resize all the div elements and the body. // JSLint: no error (execpt for "'window' is not defined." which is normal since // JSLint does nor recognize references to the global object like "window" or "self" // even if you assume a browser) // Firebug: no error // Chrome dev tools: no error // IE8: that.documentElement.clientWidth is null or not an object "use strict"; var a = that.innerWidth || that.documentElement.clientWidth, d = that.innerHeight || that.documentElement.clientHeight; (function() { for(var b = 0, c = it.getElementsByTagName("div");b < c.length;b++) { c.style.width = k(c.offsetWidth) / 100 * k(a); c.style.height = k(c.offsetHight) / 100 * k(d); } }()); (function() { var b = it.getElementsByTagName("body"); b.width = a; b.height = d; }()); }, next: function(){ // This method looks like it doesn't work. // It should change the text inside a div element // JSLint: no error (execpt for "'window' is not defined.") // Firebug: no error // Chrome dev tools: no error // IE8: no error (execpt for being painfully slow) "use strict"; var b = it.getElementById("textfield"), a = [], c; switch(c !== typeof Number){ case true: a[1] = ["HI"]; c = 0; break; case false: return Error; default: b.innerHtml = a[c]; c+=1; } } }; // auto events (function(){ "use strict"; that.onresize = MYOBJECTis.aresizer(); }()); If anyone can help me out with this I would very much appreciate it. EDIT: To answer the question what's not working I can just say that no method I showed here is working at all and I don't know the cause of the problem. I also tried to clean up some of the code that has most likely nothing to do with it. Additional information is in the comments inside the code.

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  • How to create an attached-property to change a resource's property?

    - by king.net
    I have a DrawingBrush as a resource like this: <DrawingBrush x:Key="Calendar" Stretch="Uniform"> <DrawingBrush.Drawing> <DrawingGroup> <DrawingGroup.Children> <GeometryDrawing Geometry="F1 M 28.0917,2.13333C 42.4005,2.13333 54,13.7329 54,28.0417C 54,42.3504 42.4004,53.95 28.0917,53.95C 13.7829,53.95 2.18334,42.3504 2.18334,28.0417C 2.18334,13.7329 13.7829,2.13333 28.0917,2.13333 Z "> <GeometryDrawing.Pen> <Pen Thickness="4" LineJoin="Round" Brush="#FF000000"/> </GeometryDrawing.Pen> </GeometryDrawing> <GeometryDrawing Geometry="F1 M 16.9667,16.7083L 39.7167,16.7083L 39.7167,41.625L 16.9667,41.625L 16.9667,16.7083 Z "> <GeometryDrawing.Pen> <Pen Thickness="2.66667" StartLineCap="Square" EndLineCap="Square" MiterLimit="2.75" Brush="#FF000000"/> </GeometryDrawing.Pen> </GeometryDrawing> <GeometryDrawing Brush="#FF000000" Geometry="F1 M 15.6333,15.9583L 40.7167,15.9583L 40.7167,25.2917L 15.6333,25.2917L 15.6333,15.9583 Z "/> <GeometryDrawing Brush="#FFFFFFFF" Geometry="F1 M 18.2167,11.9583L 22.9667,11.9583L 22.9667,20.875L 18.2167,20.875L 18.2167,11.9583 Z "> <GeometryDrawing.Pen> <Pen Thickness="1.33333" StartLineCap="Square" EndLineCap="Square" MiterLimit="2.75" Brush="#FF000000"/> </GeometryDrawing.Pen> </GeometryDrawing> <GeometryDrawing Brush="#FFFFFFFF" Geometry="F1 M 33.7167,11.925L 38.4667,11.925L 38.4667,20.8417L 33.7167,20.8417L 33.7167,11.925 Z "> <GeometryDrawing.Pen> <Pen Thickness="1.33333" StartLineCap="Square" EndLineCap="Square" MiterLimit="2.75" Brush="#FF000000"/> </GeometryDrawing.Pen> </GeometryDrawing> <GeometryDrawing Brush="#FF000000" Geometry="F1 M 28.0154,36.2658L 28.0154,37.4894L 21.6254,37.4894C 21.6169,37.1934 21.6615,36.908 21.7592,36.6333C 21.915,36.1815 22.165,35.7425 22.5091,35.3162C 22.8533,34.8899 23.3617,34.4091 24.0344,33.8738C 25.0782,32.983 25.776,32.295 26.1279,31.81C 26.4799,31.3249 26.6558,30.8551 26.6558,30.4005C 26.6558,29.9473 26.4894,29.5653 26.1566,29.2544C 25.8238,28.9435 25.3904,28.7881 24.8565,28.7881C 24.2915,28.7881 23.8393,28.9442 23.5001,29.2565C 23.161,29.5688 22.9892,30.0018 22.985,30.5556L 21.7614,30.4196C 21.8449,29.5345 22.1576,28.86 22.6993,28.3962C 23.241,27.9323 23.9686,27.7004 24.882,27.7004C 25.8054,27.7004 26.5358,27.9596 27.0733,28.4779C 27.6107,28.9963 27.8795,29.6385 27.8795,30.4047C 27.8795,30.7942 27.8065,31.1769 27.6607,31.5529C 27.5148,31.9289 27.2726,32.3251 26.9341,32.7415C 26.5957,33.1579 26.0115,33.7215 25.1816,34.4325C 24.4692,35.0216 24.0008,35.4214 23.7763,35.6317C 23.5518,35.842 23.3667,36.0533 23.2208,36.2658L 28.0154,36.2658 Z "/> <GeometryDrawing Brush="#FF000000" Geometry="F1 M 33.3178,37.4894L 33.3178,35.1781L 28.9671,35.1781L 28.9671,33.9545L 33.5897,27.8364L 34.5414,27.8364L 34.5414,33.9545L 35.765,33.9545L 35.765,35.1781L 34.5414,35.1781L 34.5414,37.4894L 33.3178,37.4894 Z M 33.3178,33.9545L 33.3178,30.1774L 30.4648,33.9545L 33.3178,33.9545 Z "/> </DrawingGroup.Children> </DrawingGroup> </DrawingBrush.Drawing> </DrawingBrush> And I can use it like this: <Rectangle Fill="{DynamicResource Calender}" /> Now, my question is: how can I create an attached-property to change all brushes on my resource? e.g. I be able to create this: <Rectangle Fill="{DynamicResource Calendar}" attached:IconHelper.Foreground="Blue" /> on my Rectangle and in my resource, I can get: <DrawingBrush x:Key="Calendar" Stretch="Uniform"> <DrawingBrush.Drawing> <DrawingGroup> <DrawingGroup.Children> <GeometryDrawing Geometry="blah blah"> <GeometryDrawing.Pen> <Pen Brush={attached:ReadItFromAboveRectangle}/> </GeometryDrawing.Pen> </GeometryDrawing> <GeometryDrawing Geometry="blah blah"> <GeometryDrawing.Pen> <Pen Brush={attached:ReadItFromAboveRectangle}/> </GeometryDrawing.Pen> <!-- etc... --> Is there any way to read an attached-property on Rectangle in Calendar resource? Or is there any other way to do this? Thanks in advance.

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  • Help with shopping cart in javascript

    - by user228390
    Hey guys, I'm having problems with my shopping cart. What I am trying to do is make a function that will add an item the cart and then and function that will view the cart and show the details. But what I have got so far does not do that, it just simply adds and goes straight to view cart. Also I wanted to store the name of each items in different global arrays (name, price and sum) but I can't get it work that way. Can any help me overcome this problem? Edit: I've tried to get it to work by adding some more items and attaching it to another html page, but now the code does not seem to work at all , before it showed the price and total and now I get nothing . javascript code function round_total (c) { var pennies = c * 100; pennies = Math.round(pennies); var strPennies = "" + pennies; var len = strPennies.length; return parseFloat(strPennies.substring(0, len - 2) + "." + strPennies.substring(len - 2, len)); } // End of round_total function. /* Start of generate_page function. */ function generate_page (form) { tax = 0.08; delivery_p = 2.99; var odate = new Date(); var qty = form.quantity.value; var product_v = new String(form.product.value); var total_price = product_v.substr(product_v.indexOf("$") + 1, product_v.length - product_v.indexOf("$")); var price_without_tax = round_total(qty * total_price); var ttax = round_total(price_without_tax * tax); var delivery = round_total(qty * delivery_p); var total_p = round_total(price_without_tax + ttax + delivery); document.writeln("Quantity: " + qty + "<br>"); document.writeln("Price: $" + total_price + "<br>"); document.writeln("Delivery: $" + delivery + "<br>"); document.writeln("Total: $" + total_p + "<br>"); document.writeln("Order placed on: " + odate.toGMTString()); } function calculate() { round_total (c)(); generate_page (form)(); } HTML code: Shopping cart Welcome, Guest Login Sign Up Stay Updated: Subscribe via RSS Email Updates <div id="header"> <div id="branding" class="container"> <h1>The Finest Toy<br /> Store Online</h1> <p class="desc">If you're looking for a toy shop then look no further.<br/> Go on, treat the kids with our huge selection of<br/>online toy shops selling toys for all ages.</p> </div><!-- end branding --> <div id="navigation"> <ul id="menu" class="container"> <li><a href="#">HOME</a></li> <li><a href="#">ABOUT</a></li> <li><a href="#">Online Store</a></li> <li><a href="#">CONTACT</a></li> </ul> </div><!-- end navigation --> </div><!-- end header --> Shopping Cart Nintendo DS Xbox Product: Console £149.99 Console + Games £169.99 Quantity: Product: Console £149.99 Console + Games £169.99 Quantity:     Playstation 3 Wii Product: Console £149.99 Console + Games £169.99 Quantity:   Product: Console £149.99 Console + Games £169.99 Quantity:        <input type="submit" value="Add to cart" name="submit" onClick="cart()";/><input , type="reset" value="Reset" name="reset" Copyright © 2010 shopping cart. Content and Header © |Back to top Do I need to show my CSS as well? (Sorry about the coding its not working properly for me, its not showing up the way it should be)

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  • Find the set of largest contiguous rectangles to cover multiple areas

    - by joelpt
    I'm working on a tool called Quickfort for the game Dwarf Fortress. Quickfort turns spreadsheets in csv/xls format into a series of commands for Dwarf Fortress to carry out in order to plot a "blueprint" within the game. I am currently trying to optimally solve an area-plotting problem for the 2.0 release of this tool. Consider the following "blueprint" which defines plotting commands for a 2-dimensional grid. Each cell in the grid should either be dug out ("d"), channeled ("c"), or left unplotted ("."). Any number of distinct plotting commands might be present in actual usage. . d . d c c d d d d c c . d d d . c d d d d d c . d . d d c To minimize the number of instructions that need to be sent to Dwarf Fortress, I would like to find the set of largest contiguous rectangles that can be formed to completely cover, or "plot", all of the plottable cells. To be valid, all of a given rectangle's cells must contain the same command. This is a faster approach than Quickfort 1.0 took: plotting every cell individually as a 1x1 rectangle. This video shows the performance difference between the two versions. For the above blueprint, the solution looks like this: . 9 . 0 3 2 8 1 1 1 3 2 . 1 1 1 . 2 7 1 1 1 4 2 . 6 . 5 4 2 Each same-numbered rectangle above denotes a contiguous rectangle. The largest rectangles take precedence over smaller rectangles that could also be formed in their areas. The order of the numbering/rectangles is unimportant. My current approach is iterative. In each iteration, I build a list of the largest rectangles that could be formed from each of the grid's plottable cells by extending in all 4 directions from the cell. After sorting the list largest first, I begin with the largest rectangle found, mark its underlying cells as "plotted", and record the rectangle in a list. Before plotting each rectangle, its underlying cells are checked to ensure they are not yet plotted (overlapping a previous plot). We then start again, finding the largest remaining rectangles that can be formed and plotting them until all cells have been plotted as part of some rectangle. I consider this approach slightly more optimized than a dumb brute-force search, but I am wasting a lot of cycles (re)calculating cells' largest rectangles and checking underlying cells' states. Currently, this rectangle-discovery routine takes the lion's share of the total runtime of the tool, especially for large blueprints. I have sacrificed some accuracy for the sake of speed by only considering rectangles from cells which appear to form a rectangle's corner (determined using some neighboring-cell heuristics which aren't always correct). As a result of this 'optimization', my current code doesn't actually generate the above solution correctly, but it's close enough. More broadly, I consider the goal of largest-rectangles-first to be a "good enough" approach for this application. However I observe that if the goal is instead to find the minimum set (fewest number) of rectangles to completely cover multiple areas, the solution would look like this instead: . 3 . 5 6 8 1 3 4 5 6 8 . 3 4 5 . 8 2 3 4 5 7 8 . 3 . 5 7 8 This second goal actually represents a more optimal solution to the problem, as fewer rectangles usually means fewer commands sent to Dwarf Fortress. However, this approach strikes me as closer to NP-Hard, based on my limited math knowledge. Watch the video if you'd like to better understand the overall strategy; I have not addressed other aspects of Quickfort's process, such as finding the shortest cursor-path that plots all rectangles. Possibly there is a solution to this problem that coherently combines these multiple strategies. Help of any form would be appreciated.

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  • Transferring data from 2d Dynamic array in C to CUDA and back

    - by Soumya
    I have a dynamically declared 2D array in my C program, the contents of which I want to transfer to a CUDA kernel for further processing. Once processed, I want to populate the dynamically declared 2D array in my C code with the CUDA processed data. I am able to do this with static 2D C arrays but not with dynamically declared C arrays. Any inputs would be welcome! I mean the dynamic array of dynamic arrays. The test code that I have written is as below. #include "cuda_runtime.h" #include "device_launch_parameters.h" #include <stdio.h> #include <conio.h> #include <math.h> #include <stdlib.h> const int nItt = 10; const int nP = 5; __device__ int d_nItt = 10; __device__ int d_nP = 5; __global__ void arr_chk(float *d_x_k, float *d_w_k, int row_num) { int index = (blockIdx.x * blockDim.x) + threadIdx.x; int index1 = (row_num * d_nP) + index; if ( (index1 >= row_num * d_nP) && (index1 < ((row_num +1)*d_nP))) //Modifying only one row data pertaining to one particular iteration { d_x_k[index1] = row_num * d_nP; d_w_k[index1] = index; } } float **mat_create2(int r, int c) { float **dynamicArray; dynamicArray = (float **) malloc (sizeof (float)*r); for(int i=0; i<r; i++) { dynamicArray[i] = (float *) malloc (sizeof (float)*c); for(int j= 0; j<c;j++) { dynamicArray[i][j] = 0; } } return dynamicArray; } /* Freeing memory - here only number of rows are passed*/ void cleanup2d(float **mat_arr, int x) { int i; for(i=0; i<x; i++) { free(mat_arr[i]); } free(mat_arr); } int main() { //float w_k[nItt][nP]; //Static array declaration - works! //float x_k[nItt][nP]; // if I uncomment this dynamic declaration and comment the static one, it does not work..... float **w_k = mat_create2(nItt,nP); float **x_k = mat_create2(nItt,nP); float *d_w_k, *d_x_k; // Device variables for w_k and x_k int nblocks, blocksize, nthreads; for(int i=0;i<nItt;i++) { for(int j=0;j<nP;j++) { x_k[i][j] = (nP*i); w_k[i][j] = j; } } for(int i=0;i<nItt;i++) { for(int j=0;j<nP;j++) { printf("x_k[%d][%d] = %f\t",i,j,x_k[i][j]); printf("w_k[%d][%d] = %f\n",i,j,w_k[i][j]); } } int size1 = nItt * nP * sizeof(float); printf("\nThe array size in memory bytes is: %d\n",size1); cudaMalloc( (void**)&d_x_k, size1 ); cudaMalloc( (void**)&d_w_k, size1 ); if((nP*nItt)<32) { blocksize = nP*nItt; nblocks = 1; } else { blocksize = 32; // Defines the number of threads running per block. Taken equal to warp size nthreads = blocksize; nblocks = ceil(float(nP*nItt) / nthreads); // Calculated total number of blocks thus required } for(int i = 0; i< nItt; i++) { cudaMemcpy( d_x_k, x_k, size1,cudaMemcpyHostToDevice ); //copy of x_k to device cudaMemcpy( d_w_k, w_k, size1,cudaMemcpyHostToDevice ); //copy of w_k to device arr_chk<<<nblocks, blocksize>>>(d_x_k,d_w_k,i); cudaMemcpy( x_k, d_x_k, size1, cudaMemcpyDeviceToHost ); cudaMemcpy( w_k, d_w_k, size1, cudaMemcpyDeviceToHost ); } printf("\nVerification after return from gpu\n"); for(int i = 0; i<nItt; i++) { for(int j=0;j<nP;j++) { printf("x_k[%d][%d] = %f\t",i,j,x_k[i][j]); printf("w_k[%d][%d] = %f\n",i,j,w_k[i][j]); } } cudaFree( d_x_k ); cudaFree( d_w_k ); cleanup2d(x_k,nItt); cleanup2d(w_k,nItt); getch(); return 0;

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  • How to get latitude and longitude position that stored in MySQL and use it in Android map application

    - by gunawan haruna
    I have tried to get the latitude and longitude position that was stored in MySQL. I want use the values to my Android map application. Here is my code: deskripsi.Java Button direction = (Button) findViewById (R.id.btnDir); direction.setOnClickListener(new OnClickListener(){ public void onClick(View arg0) { Intent z = getIntent(); des_lat = z.getExtras().getString("des_lat"); des_long = z.getExtras().getString("des_long"); Intent i = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://maps.google.com/maps?&daddr="+des_lat+","+des_long)); //("geo:37.827500,-122.481670")); startActivity(i); } }); And here is the content.Java private ListView list; int x; private String panjang[]; public void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.kontent); super.initButtonSearch(); list = (ListView) findViewById(R.id.list); JSONObject jo; try { jo = new JSONObject(JsonKontent); JSONArray ja = jo.getJSONArray("result"); System.out.println("Panjang : " + ja.length()); if (ja.length() == 0) { Toast.makeText(Content.this, "Data tidak ada!", Toast.LENGTH_LONG).show(); finish(); } content_id = new String[ja.length()]; c_title = new String[ja.length()]; c_telephone = new String[ja.length()]; c_short_description = new String[ja.length()]; c_long_description = new String[ja.length()]; c_image1 = new String[ja.length()]; c_image2 = new String[ja.length()]; l_address = new String[ja.length()]; catagory_id = new String[ja.length()]; Location myLoc = new Location("sharedPreferences"); Location restLoc = new Location("restaurantTable"); l_latitude = new String[ja.length()]; l_longitude = new String[ja.length()]; c_name = new String[ja.length()]; panjang = new String[ja.length()]; for (x = 0; x < ja.length(); x++) { JSONObject joj = ja.getJSONObject(x); content_id[x] = joj.getString("content_id"); catagory_id[x] = joj.getString("catagory_id"); c_title[x] = joj.getString("c_title"); c_telephone[x] = joj.getString("c_telephone"); c_short_description[x] = joj.getString("c_short_description"); c_long_description[x] = joj.getString("c_long_description"); c_image1[x] = HTTPConnection.urlPicture + joj.getString("c_image1"); c_image2[x] = HTTPConnection.urlPicture + joj.getString("c_image2"); l_address[x] = joj.getString("l_address"); l_latitude[x] = joj.getString("l_latitude"); l_longitude[x] = joj.getString("l_longitude"); c_name[x] = joj.getString("c_name"); myLoc.setLatitude(myLatitude); myLoc.setLongitude(myLongitude); restLoc.setLatitude(Double.parseDouble(l_latitude[x])); restLoc.setLongitude(Double.parseDouble(l_longitude[x])); float f = myLoc.distanceTo(restLoc); int f_int = Math.round(f / 100); f = Float.valueOf(f_int) / 10; String dist = new DecimalFormat("#,##0.0").format(f); System.out.println("Panjang " + dist + " km"); panjang[x] = dist + " km"; } } catch (JSONException e) { Toast.makeText(Content.this, "Data yang dicari tidak ada!", Toast.LENGTH_LONG).show(); finish(); } PFCAdapter adapter = new PFCAdapter(this, c_image1, c_title, l_address, panjang); list.setAdapter(adapter); list.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // TODO Auto-generated method stub System.out.println("Content ID: " + Content.content_id[Deskripsi.id]); Deskripsi.id = arg2; waitDialog = ProgressDialog.show(Content.this, "Memuat", "Harap tunggu, sedang terhubung dengan server"); waitDialog.setIcon(R.drawable.iconnya); waitDialog.show(); new LihatRatingTask().execute(); } }); } class LihatRatingTask extends AsyncTask<Void, Void, Void> { protected Void doInBackground(Void... Arg0) { Deskripsi.jsonRating = HTTPConnection.openUrl(HTTPConnection.host + "lihat_rating.php?content_id=" + Content.content_id[Deskripsi.id]); Deskripsi.jsonSubCategory = HTTPConnection .openUrl(HTTPConnection.host + "sub_catagory_parameter.php?content_id=" + Content.content_id[Deskripsi.id]); RoutePath.place = HTTPConnection .LoadImageFromWeb(HTTPConnection.host + "Logo/" + image[Integer.valueOf(catagory_id[Deskripsi.id]) - 1]); Intent i = new Intent(Content.this, Deskripsi.class); i.putExtra("des_lat", l_latitude); i.putExtra("des_long", l_longitude); startActivity(i); waitDialog.dismiss(); return null; } protected void onPostExecute(Void result) { // TODO Auto-generated method stub super.onPostExecute(result); waitDialog.dismiss(); } } } The result is in destination EditText in maps application for Android "null,null" How to make it "destination_latitude, destination_longitude"? Help me please.

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