Search Results

Search found 29037 results on 1162 pages for 'cold start'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 146/1162 | < Previous Page | 142 143 144 145 146 147 148 149 150 151 152 153  | Next Page >

  • What is the best algorithm for this array-comparison problem?

    - by mark
    What is the most efficient for speed algorithm to solve the following problem? Given 6 arrays, D1,D2,D3,D4,D5 and D6 each containing 6 numbers like: D1[0] = number D2[0] = number ...... D6[0] = number D1[1] = another number D2[1] = another number .... ..... .... ...... .... D1[5] = yet another number .... ...... .... Given a second array ST1, containing 1 number: ST1[0] = 6 Given a third array ans, containing 6 numbers: ans[0] = 3, ans[1] = 4, ans[2] = 5, ......ans[5] = 8 Using as index for the arrays D1,D2,D3,D4,D5 and D6, the number that goes from 0, to the number stored in ST1[0] minus one, in this example 6, so from 0 to 6-1, compare each res array against each D array My algorithm so far is: I tried to keep everything unlooped as much as possible. EML := ST1[0] //number contained in ST1[0] EML1 := 0 //start index for the arrays D While EML1 < EML if D1[ELM1] = ans[0] goto two if D2[ELM1] = ans[0] goto two if D3[ELM1] = ans[0] goto two if D4[ELM1] = ans[0] goto two if D5[ELM1] = ans[0] goto two if D6[ELM1] = ans[0] goto two ELM1 = ELM1 + 1 return 0 //If the ans[0] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers two: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[1] goto three if D2[ELM1] = ans[1] goto three if D3[ELM1] = ans[1] goto three if D4[ELM1] = ans[1] goto three if D5[ELM1] = ans[1] goto three if D6[ELM1] = ans[1] goto three ELM1 = ELM1 + 1 return 0 //If the ans[1] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers three: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[2] goto four if D2[ELM1] = ans[2] goto four if D3[ELM1] = ans[2] goto four if D4[ELM1] = ans[2] goto four if D5[ELM1] = ans[2] goto four if D6[ELM1] = ans[2] goto four ELM1 = ELM1 + 1 return 0 //If the ans[2] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers four: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[3] goto five if D2[ELM1] = ans[3] goto five if D3[ELM1] = ans[3] goto five if D4[ELM1] = ans[3] goto five if D5[ELM1] = ans[3] goto five if D6[ELM1] = ans[3] goto five ELM1 = ELM1 + 1 return 0 //If the ans[3] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers five: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[4] goto six if D2[ELM1] = ans[4] goto six if D3[ELM1] = ans[4] goto six if D4[ELM1] = ans[4] goto six if D5[ELM1] = ans[4] goto six if D6[ELM1] = ans[4] goto six ELM1 = ELM1 + 1 return 0 //If the ans[4] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers six: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[5] return 1 ////If the ans[1] number is not found in either D1[0-6]..... if D2[ELM1] = ans[5] return 1 which will then include ans[0-6] numbers return 1 if D3[ELM1] = ans[5] return 1 if D4[ELM1] = ans[5] return 1 if D5[ELM1] = ans[5] return 1 if D6[ELM1] = ans[5] return 1 ELM1 = ELM1 + 1 return 0 As language of choice, it would be pure c

    Read the article

  • Craziest JavaScript behavior I've ever seen

    - by Dan Ray
    And that's saying something. This is based on the Google Maps sample for Directions in the Maps API v3. <html> <head> <meta name="viewport" content="initial-scale=1.0, user-scalable=no"/> <meta http-equiv="content-type" content="text/html; charset=UTF-8"/> <title>Google Directions</title> <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script> <script type="text/javascript"> var directionDisplay; var directionsService = new google.maps.DirectionsService(); var map; function initialize() { directionsDisplay = new google.maps.DirectionsRenderer(); var myOptions = { zoom:7, mapTypeId: google.maps.MapTypeId.ROADMAP } map = new google.maps.Map(document.getElementById("map_canvas"), myOptions); directionsDisplay.setMap(map); directionsDisplay.setPanel(document.getElementById("directionsPanel")); } function render() { var start; if(navigator.geolocation) { navigator.geolocation.getCurrentPosition(function(position) { start = new google.maps.LatLng(position.coords.latitude,position.coords.longitude); }, function() { handleNoGeolocation(browserSupportFlag); }); } else { // Browser doesn't support Geolocation handleNoGeolocation(); } alert("booga booga"); var end = '<?= $_REQUEST['destination'] ?>'; var request = { origin:start, destination:end, travelMode: google.maps.DirectionsTravelMode.DRIVING }; directionsService.route(request, function(response, status) { if (status == google.maps.DirectionsStatus.OK) { directionsDisplay.setDirections(response); } }); } </script> </head> <body style="margin:0px; padding:0px;" onload="initialize()"> <div><div id="map_canvas" style="float:left;width:70%; height:100%"></div> <div id="directionsPanel" style="float:right;width:30%;height 100%"></div> <script type="text/javascript">render();</script> </body> </html> See that "alert('booga booga')" in there? With that in place, this all works fantastic. Comment that out, and var start is undefined when we hit the line to define var request. I discovered this when I removed the alert I put in there to show me the value of var start, and it quit working. If I DO ask it to alert me the value of var start, it tells me it's undefined, BUT it has a valid (and accurate!) value when we define var request a few lines later. I'm suspecting it's a timing issue--like an asynchronous something is having time to complete in the background in the moment it takes me to dismiss the alert. Any thoughts on work-arounds?

    Read the article

  • Algorithm to select groups of similar items in 2d array

    - by mafutrct
    There is a 2d array of items (in my case they are called Intersections). A certain item is given as a start. The task is to find all items directly or indirectly connected to this item that satisfy a certain function. So the basic algorithm is like this: Add the start to the result list. Repeat until no modification: Add each item in the array that satisfies the function and touches any item in the result list to the result list. My current implementation looks like this: private IList<Intersection> SelectGroup ( Intersection start, Func<Intersection, Intersection, bool> select) { List<Intersection> result = new List<Intersection> (); Queue<Intersection> source = new Queue<Intersection> (); source.Enqueue (start); while (source.Any ()) { var s = source.Dequeue (); result.Add (s); foreach (var neighbour in Neighbours (s)) { if (select (start, neighbour) && !result.Contains (neighbour) && !source.Contains (neighbour)) { source.Enqueue (neighbour); } } } Debug.Assert (result.Distinct ().Count () == result.Count ()); Debug.Assert (result.All (x => select (x, result.First ()))); return result; } private List<Intersection> Neighbours (IIntersection intersection) { int x = intersection.X; int y = intersection.Y; List<Intersection> list = new List<Intersection> (); if (x > 1) { list.Add (GetIntersection (x - 1, y)); } if (y > 1) { list.Add (GetIntersection (x, y - 1)); } if (x < Size) { list.Add (GetIntersection (x + 1, y)); } if (y < Size) { list.Add (GetIntersection (x, y + 1)); } return list; } (The select function takes a start item and returns true iff the second item satisfies.) This does its job and turned out to be reasonable fast for the usual array sizes (about 20*20). However, I'm interested in further improvements. Any ideas? Example (X satisfies in relation to other Xs, . does never satisfy): .... XX.. .XX. X... In this case, there are 2 groups: a central group of 4 items and a group of a single item in the lower left. Selecting the group (for instance by starting item [2, 2]) returns the former, while the latter can be selected using the starting item and sole return value [0, 3]. Example 2: .A.. ..BB A.AA This time there are 4 groups. The 3 A groups are not connected, so they are returned as separate groups. The bigger A and B groups are connected, but A does not related to B so they are returned as separate groups.

    Read the article

  • BFS Shortest Path: Edge weight either 1 or 2

    - by Hackster
    I am trying to implement a shortest path algorithm using BFS. That is I am trying to find the shortest path from a specified vertex to every other vertex. However, its a special case where all edge weights are either 1 or 2. I know it could be done with Dijkstra's algorithm but I must use Breadth First Search. So far I have a working version of BFS that searches first for a vertex connected with an edge of weight 1. If it cannot find it, then returns a vertex connected with an edge of weight 2. After thinking about it, this is not the correct way to find the shortest path. The problem is I cannot think of any reasoning why BFS would work with weights 1 or 2, as opposed to any weight. Here is the code: public void addEdge(int start, int end, int weight) { adjMat[start][end] = 1; adjMat[end][start] = 1; edge_weight[start][end] = weight; edge_weight[end][start] = weight; } // ------------------------------------------------------------- public void bfs() // breadth-first search { // begin at vertex 0 vertexList[0].wasVisited = true; // mark it displayVertex(0); // display it theQueue.insert(0); // insert at tail int v2; while( !theQueue.isEmpty() ) // until queue empty, { int v1 = theQueue.remove(); // remove vertex at head // until it has no unvisited neighbors while( (v2=getAdjUnvisitedVertex(v1)) != -1 ){// get one, vertexList[v2].wasVisited = true; // mark it displayVertex(v2); // display it theQueue.insert(v2); // insert it } } // end while(queue not empty) // queue is empty, so we're done for(int j=0; j<nVerts; j++) // reset flags vertexList[j].wasVisited = false; } // end bfs() // ------------------------------------------------------------- // returns an unvisited vertex adj to v -- ****WITH WEIGHT 1**** public int getAdjUnvisitedVertex(int v) { for (int j = 0; j < nVerts; j++) if (adjMat[v][j] == 1 && vertexList[j].wasVisited == false && edge_weight[v][j] == 1){ //System.out.println("Vertex found with 1:"+ vertexList[j].label); return j; } for (int k = 0; k < nVerts; k++) if (adjMat[v][k] == 1 && vertexList[k].wasVisited == false && edge_weight[v][k] == 2){ //System.out.println("Vertex found with 2:"+vertexList[k].label); return k; } return -1; } // end getAdjUnvisitedVertex() // ------------------------------------------------------------- } //////////////////////////////////////////////////////////////// public class BFS{ public static void main(String[] args) { Graph theGraph = new Graph(); theGraph.addVertex('A'); // 0 (start for bfs) theGraph.addVertex('B'); // 1 theGraph.addVertex('C'); // 2 theGraph.addEdge(0, 1,2); // AB theGraph.addEdge(1, 2,1); // BC theGraph.addEdge(2, 0,1); // AD System.out.print("Visits: "); theGraph.bfs(); // breadth-first search System.out.println(); } // end main() } The problem then is, that I don't know why BFS can work for the shortest path problem with edges of weight 1 or 2 as opposed to any edges of any weight. Any help is appreciated. Thanks!

    Read the article

  • Android MediaPlayer Won't Play Different Sounds

    - by cYn
    I'm making a simple app that plays a different sound according to its orientation. So if it's placed face down, a sound is played. If placed on its left side, a different sound is played. I'm having a hard time manipulating MediaPlayer correctly. My app runs fine. But it will only play one sound. For example. When I first boot up my app and place my device facing up, a sound will play. If I change its orientation, the sound will pause. But it will not start a different sound in a different orientation. BUT, if I place the device back facing up, it resumes the sound that it paused. I know I'm doing something wrong here, but I can't seem to figure it out the correct structure in using MediaPlayer and the program constantly calling it through onSensorChanged. public class MainActivity extends Activity implements SensorEventListener{ MediaPlayer mpAudioAttention; MediaPlayer mpAudioAssembly; MediaPlayer mpAudioRecall; MediaPlayer mpAudioRetreat; MediaPlayer mpAudioReveille; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); sm = (SensorManager) getSystemService(SENSOR_SERVICE); setContentView(R.layout.main); mpAudioAttention = MediaPlayer.create(this, R.raw.attention); mpAudioAssembly = MediaPlayer.create(this, R.raw.assembly); mpAudioRecall = MediaPlayer.create(this, R.raw.recall); mpAudioRetreat = MediaPlayer.create(this, R.raw.retreat); mpAudioReveille = MediaPlayer.create(this, R.raw.reveille); } public void onSensorChanged(SensorEvent event) { synchronized (this) { Log.d(tag, "onSensorChanged: " + event + ", z: " + event.values[0] + ", x: " + event.values[1] + ", y: " + event.values[2]); zViewO.setText("Orientation Z: " + event.values[0]); xViewO.setText("Orientation X: " + event.values[1]); yViewO.setText("Orientation Y: " + event.values[2]); } //face down if (event.values[2] > -11 && event.values[2] < -9){ mpAudioRetreat.start(); } else mpAudioRetreat.pause(); //face up if (event.values[2] < 11 && event.values[2] > 9){ mpAudioReveille.start(); } else mpAudioReveille.pause(); //standing if (event.values[0] > -10 && event.values[0] < -8){ mpAudioAttention.start(); } else mpAudioAttention.pause(); //left sideways if (event.values[1] < 11 && event.values[1] > 9){ mpAudioAssembly.start(); } else mpAudioAssembly.pause(); //right sideways if (event.values[1] > -11 && event.values[1] < -9){ mpAudioRecall.start(); } else mpAudioRecall.pause(); }

    Read the article

  • Rotating images makes ui slow

    - by 5w4rley
    i'm trying to implement kind of speedometer. i'm getting informations about rounds per minute, boost and load of an engine over bluetooth and i try to display them on the screen witch 3 arrows witch should point in the right direktion. i tried to use a rotate animation evry time i get data(10-100ms) to setup the arrows. but that makes my ui extremly slow. 500ms to react on a buttonclick. Doese someone know how to make it work better? source code: public void setTacho() { //rotate Tachonadel Rpmcurrentdegree=Rpmcurrentdegree+Rpmdegree; Rpmdegree=((rpms-lastrpm)*RPMtoDegree); RpmAnim=new RotateAnimation((float)Rpmcurrentdegree, (float)Rpmdegree, ivNadel.getWidth()/2, ivNadel.getHeight()/2); RpmAnim.setFillEnabled(true); RpmAnim.setFillAfter(true); ivNadel.setAnimation(RpmAnim); RpmAnim.start(); //rotate Boostbalken currentBoostDegree=currentBoostDegree+BoostDegree; BoostDegree=(boost-lastBoost)*BOOSTtoDegree; //rotate Loadbalken currentLoadDegree=currentLoadDegree+LoadDegree; LoadDegree=(load-lastLoad)*LOADtoDegree; BoostAnim=new RotateAnimation((float)-currentBoostDegree, (float)-BoostDegree, ivBoost.getWidth()/2, ivBoost.getHeight()/2); BoostAnim.setFillEnabled(true); BoostAnim.setFillAfter(true); ivBoost.setAnimation(BoostAnim); BoostAnim.start(); LoadAnim=new RotateAnimation((float)currentLoadDegree, (float)LoadDegree, ivLoad.getWidth()/2, ivLoad.getHeight()/2); LoadAnim.setFillEnabled(true); LoadAnim.setFillAfter(true); ivLoad.setAnimation(LoadAnim); LoadAnim.start(); } when i try to make the rotation only if the values have changed then it works only while they are changing but if they aren't the arrows jump back to the zero position. isnt setfillafter to tell the image that it should hold the new position? code: public void setTacho() { //rotate Tachonadel Rpmcurrentdegree=Rpmcurrentdegree+Rpmdegree; Rpmdegree=((rpms-lastrpm)*RPMtoDegree); if(Rpmdegree!=0) { RpmAnim=new RotateAnimation((float)Rpmcurrentdegree, (float)Rpmdegree, ivNadel.getWidth()/2, ivNadel.getHeight()/2); RpmAnim.setFillEnabled(true); RpmAnim.setFillAfter(true); ivNadel.setAnimation(RpmAnim); RpmAnim.start(); } //rotate Boostbalken currentBoostDegree=currentBoostDegree+BoostDegree; BoostDegree=(boost-lastBoost)*BOOSTtoDegree; //rotate Loadbalken currentLoadDegree=currentLoadDegree+LoadDegree; LoadDegree=(load-lastLoad)*LOADtoDegree; if(BoostDegree!=0) { BoostAnim=new RotateAnimation((float)-currentBoostDegree, (float)-BoostDegree, ivBoost.getWidth()/2, ivBoost.getHeight()/2); BoostAnim.setFillEnabled(true); BoostAnim.setFillAfter(true); ivBoost.setAnimation(BoostAnim); BoostAnim.start(); } if(LoadDegree!=0) { LoadAnim=new RotateAnimation((float)currentLoadDegree, (float)LoadDegree, ivLoad.getWidth()/2, ivLoad.getHeight()/2); LoadAnim.setFillEnabled(true); LoadAnim.setFillAfter(true); ivLoad.setAnimation(LoadAnim); LoadAnim.start(); } } i don't get it =( thx 4 help EDIT: part of the bluetooth Thread that calls the callback while (run) { try { bytes = mmInStream.read(buffer); if (connection.btCallback != null) { connection.btCallback.getData(buffer,bytes); } } catch (IOException e) { break; } the callback methode of the bluetooth thread: public void getData(byte[] bytes, int len) { setTacho(); }

    Read the article

  • "No message serializer has been configured" error when starting NServiceBus endpoint

    - by SteveBering
    My GenericHost hosted service is failing to start with the following message: 2010-05-07 09:13:47,406 [1] FATAL NServiceBus.Host.Internal.GenericHost [(null)] <(null) - System.InvalidOperationException: No message serializer has been con figured. at NServiceBus.Unicast.Transport.Msmq.MsmqTransport.CheckConfiguration() in d:\BuildAgent-02\work\672d81652eaca4e1\src\impl\unicast\NServiceBus.Unicast.Msmq\ MsmqTransport.cs:line 241 at NServiceBus.Unicast.Transport.Msmq.MsmqTransport.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\impl\unicast\NServiceBus.Unicast.Msmq\MsmqTransport .cs:line 211 at NServiceBus.Unicast.UnicastBus.NServiceBus.IStartableBus.Start(Action startupAction) in d:\BuildAgent-02\work\672d81652eaca4e1\src\unicast\NServiceBus.Uni cast\UnicastBus.cs:line 694 at NServiceBus.Unicast.UnicastBus.NServiceBus.IStartableBus.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\unicast\NServiceBus.Unicast\UnicastBus.cs:l ine 665 at NServiceBus.Host.Internal.GenericHost.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\host\NServiceBus.Host\Internal\GenericHost.cs:line 77 My endpoint configuration looks like: public class ServiceEndpointConfiguration : IConfigureThisEndpoint, AsA_Publisher, IWantCustomInitialization { public void Init() { // build out persistence infrastructure var sessionFactory = Bootstrapper.InitializePersistence(); // configure NServiceBus infrastructure var container = Bootstrapper.BuildDependencies(sessionFactory); // set up logging log4net.Config.XmlConfigurator.Configure(); Configure.With() .Log4Net() .UnityBuilder(container) .XmlSerializer(); } } And my app.config looks like: <configSections> <section name="MsmqTransportConfig" type="NServiceBus.Config.MsmqTransportConfig, NServiceBus.Core" /> <section name="UnicastBusConfig" type="NServiceBus.Config.UnicastBusConfig, NServiceBus.Core" /> <section name="Logging" type="NServiceBus.Config.Logging, NServiceBus.Core" /> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" requirePermission="false" /> </configSections> <Logging Threshold="DEBUG" /> <MsmqTransportConfig InputQueue="NServiceBus.ServiceInput" ErrorQueue="NServiceBus.Errors" NumberOfWorkerThreads="1" MaxRetries="2" /> <UnicastBusConfig DistributorControlAddress="" DistributorDataAddress="" ForwardReceivedMessagesTo="NServiceBus.Auditing"> <MessageEndpointMappings> <!-- publishers don't need to set this for their own message types --> </MessageEndpointMappings> </UnicastBusConfig> <connectionStrings> <add name="Db" connectionString="Data Source=..." providerName="System.Data.SqlClient" /> </connectionStrings> <log4net debug="true"> <root> <level value="INFO"/> </root> <logger name="NHibernate"> <level value="ERROR" /> </logger> </log4net> This has worked in the past, but seems to be failing when the generic host starts. My endpoint configuration is below, along with the app.config for the service. What is strange is that in my endpoint configuration, I am specifying to use the XmlSerializer for message serialization. I don't see any other errors in the console output preceding the error message. What am I missing? Thanks, Steve

    Read the article

  • for my project I have problem in report

    - by pink rose
    public class stack { private int Array[]; private int top = -1; public int size; public stack(int size) { this.size=size; Array = new int[size]; } public void push(int j) { if (top < size) { Array[++top] = j; } } public int pop() { return Array[top--]; } public int top() { return Array[top]; } public boolean isEmpty() { return (top == -1); } } import javax.swing.JOptionPane; public class menu { private static stack s; private static int numbers[]; public static void main(String args[]) { start(); } public static void start() { int i = Integer.parseInt(JOptionPane.showInputDialog("1. size of array\n2. data entry\n3. display content\n4. exit")); switch (i) { case 1: setSize(); break; case 2: addElement(); break; case 3: showElements(); break; case 4: exit(); } } public static void setSize() { int size = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Size")); s = new stack(size); numbers = new int[10]; start(); } public static void addElement() { for(int x=0;x<s.size;x++) { int e = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Element")); numbers[e]++; s.push(e); } start(); } public static void showElements() { String result = ""; int temp; while (!s.isEmpty()) { temp = s.pop(); if (numbers[temp] == 1) { result = temp+result; } } JOptionPane.showMessageDialog(null, result); start(); } public static void exit() { System.exit(0); } } This my project I was finished but I have problem in question in my report Conclusion. It should summarize the state of your project and indicate which part of your project is working and which part is not working or with limitations. You may also provide your suggestions and comments to this project what I can answer I didn't have any idea

    Read the article

  • for my project I have problem in report

    - by pink rose
    public stack(int size) { this.size=size; Array = new int[size]; } public void push(int j) { if (top < size) { Array[++top] = j; } } public int pop() { return Array[top--]; } public int top() { return Array[top]; } public boolean isEmpty() { return (top == -1); } } import javax.swing.JOptionPane; public class menu { private static stack s; private static int numbers[]; public static void main(String args[]) { start(); } public static void start() { int i = Integer.parseInt(JOptionPane.showInputDialog("1. size of array\n2. data entry\n3. display content\n4. exit")); switch (i) { case 1: setSize(); break; case 2: addElement(); break; case 3: showElements(); break; case 4: exit(); } } public static void setSize() { int size = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Size")); s = new stack(size); numbers = new int[10]; start(); } public static void addElement() { for(int x=0;x<s.size;x++) { int e = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Element")); numbers[e]++; s.push(e); } start(); } public static void showElements() { String result = ""; int temp; while (!s.isEmpty()) { temp = s.pop(); if (numbers[temp] == 1) { result = temp+result; } } JOptionPane.showMessageDialog(null, result); start(); } public static void exit() { System.exit(0); } } This my project I was finished but I have problem in question in my report Conclusion. It should summarize the state of your project and indicate which part of your project is working and which part is not working or with limitations. You may also provide your suggestions and comments to this project what I can answer I didn't have any idea

    Read the article

  • The Collatz Sequence problem

    - by Gandalf StormCrow
    I'm trying to solve this problem, its not a homework question, its just code I'm submitting to uva.onlinejudge.org so I can learn better java trough examples. Here is the problem sample input : 3 100 34 100 75 250 27 2147483647 101 304 101 303 -1 -1 Here is simple output : Case 1: A = 3, limit = 100, number of terms = 8 Case 2: A = 34, limit = 100, number of terms = 14 Case 3: A = 75, limit = 250, number of terms = 3 Case 4: A = 27, limit = 2147483647, number of terms = 112 Case 5: A = 101, limit = 304, number of terms = 26 Case 6: A = 101, limit = 303, number of terms = 1 The thing is this has to execute within 3sec time interval otherwise your question won't be accepted as solution, here is with what I've come up so far, its working as it should just the execution time is not within 3 seconds, here is code : import java.util.Scanner; class Main { public static void main(String[] args) { Scanner stdin = new Scanner(System.in); int start; int limit; int terms; int a = 0; while (stdin.hasNext()) { start = stdin.nextInt(); limit = stdin.nextInt(); if (start > 0) { terms = getLength(start, limit); a++; } else { break; } System.out.println("Case "+a+": A = "+start+", limit = "+limit+", number of terms = "+terms); } } public static int getLength(int x, int y) { int length = 1; while (x != 1) { if (x <= y) { if ( x % 2 == 0) { x = x / 2; length++; }else{ x = x * 3 + 1; length++; } } else { length--; break; } } return length; } } And yes here is how its meant to be solved : An algorithm given by Lothar Collatz produces sequences of integers, and is described as follows: Step 1: Choose an arbitrary positive integer A as the first item in the sequence. Step 2: If A = 1 then stop. Step 3: If A is even, then replace A by A / 2 and go to step 2. Step 4: If A is odd, then replace A by 3 * A + 1 and go to step 2. And yes my question is how can I make it work inside 3 seconds time interval?

    Read the article

  • Android: Using onStart() method in Bluetooth application

    - by Nii
    Hello, I am getting a nullpointer exception when my onStart() method is called. Here is the breakdown of my Android app: Opening the app brings a user to the homescreen: The user is then presented with the first 6 icons to choose from. When the user presses the "Sugar" icon it takes them to the SugarTabActivity. The SugarTabActivity is a Tabbed layout with two tabs. I'm concerned with the first tab. The first tab calls the getDefaultAdapter() method in its onCreate() method. Once it calls this, it checks if the bluetooth adapter is null on the phone, and if its null it shows a toast saying "Bluetooth is not available". This works just fine. Then I call the onStart() method. In the onStart() method I check if bluetooth is enabled, and if it isnt, then I start a new activity from the BluetoothAdapter enable bluetooth intent; otherwise, I start my bluetooth service. The exact error I'm getting is 04-19 00:44:45.674: ERROR/AndroidRuntime(225): Caused by: java.lang.NullPointerException 04-19 00:44:45.674: ERROR/AndroidRuntime(225): at com.nii.glucose.Glucose.onStart(Glucose.java:313). Heading Override public void onCreate(Bundle icicle) { super.onCreate(icicle); if(D) Log.d(TAG, "+++ ON CREATE +++"); setContentView(R.layout.glucose_layout); mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if(mBluetoothAdapter==null){ Toast.makeText(this, "Bluetooth not available", Toast.LENGTH_LONG).show(); //finish(); return; } } Override public void onStart() { super.onStart(); if(D) Log.e(TAG, "++ ON START ++"); // If BT is not on, request that it be enabled. // setupChat() will then be called during onActivityResult if (!mBluetoothAdapter.isEnabled()) { Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableIntent, REQUEST_ENABLE_BT); // Otherwise, setup the chat session } else { if (mGlucoseService == null) mGlucoseService = new BluetoothService(this, mHandler); } } @Override public synchronized void onResume(){ super.onResume(); if(D) Log.e(TAG,"==== ON RESUME ======"); // Performing this check in onResume() covers the case in which BT was // not enabled during onStart(), so we were paused to enable it... // onResume() will be called when ACTION_REQUEST_ENABLE activity returns. if (mGlucoseService != null) { // Only if the state is STATE_NONE, do we know that we haven't started already if (mGlucoseService.getState() == BluetoothService.STATE_NONE) { // Start the Bluetooth chat services mGlucoseService.start(); } } } @Override public synchronized void onPause(){ super.onPause(); //isActive.set(false); if(D) Log.e(TAG,"==== ON PAUSE ======"); } @Override public void onDestroy() { super.onDestroy(); // Stop the Bluetooth chat services if (mGlucoseService != null) mGlucoseService.stop(); if(D) Log.e(TAG, "--- ON DESTROY ---"); }

    Read the article

  • Running a Java daemon with a GWT front-end served by embedded Jetty

    - by BinaryMuse
    Greetings, coders, Background Info and Code I am trying to create a daemon-type program (e.g., it runs constantly, polling for things to do) that is managed by a GWT application (servlets in a WAR) which is in turn served by an embedded Jetty server (using a WebAppContext). I'm having problems making the GWT application aware of the daemon object. For testing things, I currently have two projects: The daemon and embedded Jetty server in one (EmbJetTest), and the GWT application in another (DefaultApp). This is the current state of the code: First, EmbJetTest creates an embedded Jetty server like so, using a ServletContextListener to inject the daemon object into the web application context: EmbJetTest.server = new Server(8080); // Create and start the daemon Daemon daemon = new Daemon(); Thread thread = new Thread(daemon); thread.start(); // war handler WebAppContext waContext = new WebAppContext(); waContext.setContextPath("/webapp"); waContext.setWar("./apps/DefaultApp.war"); waContext.addEventListener(new DaemonLoader(daemon)); // Add it to the server EmbJetTest.server.setHandler(waContext); EmbJetTest.server.setThreadPool(new QueuedThreadPool(10)); // Start the server; join() blocks until we shut down EmbJetTest.server.start(); EmbJetTest.server.join(); // Stop the daemon thread daemon.stopLoop(); Daemon is a very simple object with a couple properties, at the moment. DaemonLoader is the following ServletContextListener implementation: private Daemon daemon; public DaemonLoader(Daemon daemon) { this.daemon = daemon; } @Override public void contextDestroyed(ServletContextEvent arg0) { } @Override public void contextInitialized(ServletContextEvent arg0) { arg0.getServletContext().setAttribute("daemon", this.daemon); } Then, in one of my servlets in the GWT application, I have the following code: Daemon daemon = (Daemon) this.getServletContext().getAttribute("daemon"); However, when I visit localhost:8080/webapp/* and invoke the servlet, this code throws a ClassCastException, even though the classes are of the same type. This StackOverflow answer indicates that this is because the two classes are loaded with different classloaders. Question My question is twofold. Am I even on the right track here? Am I going about this completely the wrong way? Something tells me I am, but I can't think of another way to make the daemon available to both applications. Is there a better way to communicate with the daemon from the GWT application? Should the GWT app own the daemon and somehow start the daemon itself? The daemon needs to run even if no one visits the one of the GWT app's servlets--how could I do this? If I am on the right track, how can I get around the classloader issue? Thanks in advance.

    Read the article

  • Is DataRow thread safe? How to update a single datarow in a datatable using multiple threads? - .net

    - by NLV
    Hello all I want to update a single datarow in a datatable using multiple threads. Is this actually possible? I've written the following code implementing a simple multi-threading to update a single datarow. I get different results each time. Why is it so? public partial class Form1 : Form { private static DataTable dtMain; private static string threadMsg = string.Empty; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { Thread[] thArr = new Thread[5]; dtMain = new DataTable(); dtMain.Columns.Add("SNo"); DataRow dRow; dRow = dtMain.NewRow(); dRow["SNo"] = 5; dtMain.Rows.Add(dRow); dtMain.AcceptChanges(); ThreadStart ts = new ThreadStart(delegate { dtUpdate(); }); thArr[0] = new Thread(ts); thArr[1] = new Thread(ts); thArr[2] = new Thread(ts); thArr[3] = new Thread(ts); thArr[4] = new Thread(ts); thArr[0].Start(); thArr[1].Start(); thArr[2].Start(); thArr[3].Start(); thArr[4].Start(); while (!WaitTillAllThreadsStopped(thArr)) { Thread.Sleep(500); } foreach (Thread thread in thArr) { if (thread != null && thread.IsAlive) { thread.Abort(); } } dgvMain.DataSource = dtMain; } private void dtUpdate() { for (int i = 0; i < 1000; i++) { try { dtMain.Rows[0][0] = Convert.ToInt32(dtMain.Rows[0][0]) + 1; dtMain.AcceptChanges(); } catch { continue; } } } private bool WaitTillAllThreadsStopped(Thread[] threads) { foreach (Thread thread in threads) { if (thread != null && thread.ThreadState == ThreadState.Running) { return false; } } return true; } } Any thoughts on this? Thank you NLV

    Read the article

  • Is it a good way to close a thread?

    - by Roman
    I have a short version of the question: I start a thread like that: counter.start();, where counter is a thread. At the point when I want to stop the thread I do that: counter.interrupt() In my thread I periodically do this check: Thread.interrupted(). If it gives true I return from the thread and, as a consequence, it stops. And here are some details, if needed: If you need more details, they are here. From the invent dispatch thread I start a counter thread in this way: public static void start() { SwingUtilities.invokeLater(new Runnable() { public void run() { showGUI(); counter.start(); } }); } where the thread is defined like that: public static Thread counter = new Thread() { public void run() { for (int i=4; i>0; i=i-1) { updateGUI(i,label); try {Thread.sleep(1000);} catch(InterruptedException e) {}; } // The time for the partner selection is over. SwingUtilities.invokeLater(new Runnable() { public void run() { frame.remove(partnerSelectionPanel); frame.add(selectionFinishedPanel); frame.invalidate(); frame.validate(); } }); } }; The thread performs countdown in the "first" window (it shows home much time left). If time limit is over, the thread close the "first" window and generate a new one. I want to modify my thread in the following way: public static Thread counter = new Thread() { public void run() { for (int i=4; i>0; i=i-1) { if (!Thread.interrupted()) { updateGUI(i,label); } else { return; } try {Thread.sleep(1000);} catch(InterruptedException e) {}; } // The time for the partner selection is over. if (!Thread.interrupted()) { SwingUtilities.invokeLater(new Runnable() { public void run() { frame.remove(partnerSelectionPanel); frame.add(selectionFinishedPanel); frame.invalidate(); frame.validate(); } }); } else { return; } } };

    Read the article

  • Trying to write a loop that uses an OutputStream to write to a text file.

    - by Steve McLain
    I'm not a java programmer, I'm a VB programmer. I am doing this as part of an assignment, however, I'm not asking for help on something assignment related. I'd like to figure out how to get the OutputStreamWriter to work properly in this instance. I just want to capture the values I'm generating and place them into a text document. The file is generated, but only one entry exists, not the 40 I'm expecting. I could do this in a heartbeat with VB, but java feels very strange to me right now. Your help is appreciated. Thanks, Steve Here's the code: public static void main(String[] args){ long start, end; double result,difference; try {//OutputStream code assistance from http://tutorials.jenkov.com/java-io/outputstreamwriter.html OutputStream outputStream = new FileOutputStream("c:\\Temp\\output1.txt"); Writer out = new OutputStreamWriter(outputStream); for(int n=1; n<=20; n++){ //Calculate the Time for n^2. start = System.nanoTime(); //Add code to call method to calculate n^2 result = mN2(n); end = System.nanoTime(); difference = (end - start); //Output results to a file out.write("N^2 End time: " + end + " Difference: " + difference + "\n"); out.close(); } } catch (IOException e){ } try { OutputStream outputStream = new FileOutputStream("c:\\Temp\\output1.txt"); Writer out = new OutputStreamWriter(outputStream); for(int n=1; n<=20; n++){ //Calculate the Time for 2^n. start = System.nanoTime(); //Add code to call method to calculate 2^n result = m2N(n); end = System.nanoTime(); difference = (end - start); //Output results to a file out.write("N^2 End time: " + end + " Difference: " + difference + "\n"); out.close(); } } catch (IOException e){ } } //Calculate N^2 public static double mN2(double n) { n = n*n; return n; } //Calculate 2N public static double m2N (double n) { n = 2*n; return n; }

    Read the article

  • AlarmManager triggers PendingIntent too soon

    - by Wezelkrozum
    I've searched for 3 days now but didn't find a solution or similar problem/question anywhere else. Here is the deal: Trigger in 1 hour - works correct Trigger in 2 hours - Goes of in 1:23 Trigger in 1 day - Goes of in ~11:00 So why is the AlarmManager so unpredictable and always too soon? Or what am I doing wrong? And is there another way so that it could work correctly? This is the way I register my PendingIntent in the AlarmManager (stripped down): AlarmManager alarmManager = (AlarmManager)parent.getSystemService(ALARM_SERVICE); Intent myIntent = new Intent(parent, UpdateKlasRoostersService.class); PendingIntent pendingIntent = PendingIntent.getService(parent, 0, myIntent, PendingIntent.FLAG_UPDATE_CURRENT); //Set startdate of PendingIntent so it triggers in 10 minutes Calendar start = Calendar.getInstance(); start.setTimeInMillis(SystemClock.elapsedRealtime()); start.add(Calendar.MINUTE, 10); //Set interval of PendingIntent so it triggers every day Integer interval = 1*24*60*60*1000; //Cancel any similar instances of this PendingIntent if already scheduled alarmManager.cancel(pendingIntent); //Schedule PendingIntent alarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, start.getTimeInMillis(), interval, pendingIntent); //Old way I used to schedule a PendingIntent, didn't seem to work either //alarmManager.set(AlarmManager.RTC_WAKEUP, start.getTimeInMillis(), pendingIntent); It would be awesome if anyone has a solution. Thanks for any help! Update: 2 hours ago it worked to trigger it with an interval of 2 hours, but after that it triggered after 1:20 hours. It's getting really weird. I'll track the triggers down with a logfile and post it here tomorrow. Update: The PendingIntent is scheduled to run every 3 hours. From the log's second line it seems like an old scheduled PendingIntent is still running: [2012-5-3 2:15:42 519] Updating Klasroosters [2012-5-3 4:15:15 562] Updating Klasroosters [2012-5-3 5:15:42 749] Updating Klasroosters [2012-5-3 8:15:42 754] Updating Klasroosters [2012-5-3 11:15:42 522] Updating Klasroosters But, I'm sure I cancelled the scheduled PendingIntent's before I schedule a new one. And every PendingIntent isn't recreated in the same way, so it should be exactly the same. If not , this threads question isn't relevant anymore.

    Read the article

  • How to create nested directories in PhoneGap

    - by Stallman
    I have tried on this, but this didn't satisfy my request at all. I write a new one: var file_system; var fs_root; window.requestFileSystem(LocalFileSystem.PERSISTENT, 1024*1024, onInitFs, request_FS_fail); function onInitFs(fs) { file_system= fs; fs_root= file_system.root; alert("ini fs"); create_Directory(); alert("ini fs done."); } var string_array; var main_dir= "story_repository/"+ User_Editime; string_array= new Array("story_repository/",main_dir, main_dir+"/rec", main_dir+"/img","story_repository/"+ User_Name ); function create_Directory(){ var start= 0; var path=""; while(start < string_array.length) { path = string_array[start]; alert(start+" th created directory " +" is "+ path); fs_root.getDirectory ( path , {create: true, exclusive: false}, function(entry) { alert(path +"is created."); }, create_dir_err() ); start++; }//while loop }//create_Directory function create_dir_err() { alert("Recursively create directories error."); } function request_FS_fail() { alert("Failed to request File System "); } Although the directories are created, the it sends me ErrorCallback:"alert("Recursively create directories error.");" Firstly, I don't think this code will work since I have tried on this: This one failed: window.requestFileSystem( LocalFileSystem.PERSISTENT, 0, //request file system success callback. function(fileSys) { fileSys.root.getDirectory( "story_repository/"+ dir_name, {create: true, exclusive: false}, //Create directory story_repository/Stallman_time. function(directory) { alert("Create directory: "+ "story_repository/"+ dir_name); //create dir_name/img/ fileSys.root.getDirectory { "story_repository/"+ dir_name + "/img/", {create: true, exclusive: false}, function(directory) { alert("Create a directory: "+ "story_repository/"+ dir_name + "/img/"); //check. //create dir_name/rec/ fileSys.root.getDirectory { "story_repository/"+ dir_name + "/rec/", {create: true, exclusive: false}, function(directory) { alert("Create a directory: "+ "story_repository/"+ dir_name + "/rec/"); //check. //Go ahead. }, createError } //create dir_name/rec/ }, createError } //create dir_name/img }, createError); }, //Create directory story_repository/Stallman_time. createError()); } I just repeatedly call fs.root.getDirectory only but it failed. But the first one is almost the same... 1. What is the problem at all? Why does the first one always gives me the ErrorCallback? 2. Why can't the second one work? 3. Does anyone has a better solution?(no ErrorcallBack msg) ps: I work on Android and PhoneGap 1.7.0.

    Read the article

  • Ruby on Rails: jQuery datepicker - dates between validation

    - by Jazz
    I have an app that allows a user to create new projects, and the search for them later. One of the options they have when creating a project is giving them start and end dates. At the moment all the code works properly for creating and searching on the dates, but I am now wanting to restrict what dates the user can enter. I am needing for an error to flag up when the user tries to enter an end date that is before the start date. It's really more for when the user is creating the project. Here is my code so far = Application.js //= require jquery //= require jquery_ujs //= require jquery-ui //= require jquery.ui.all //= require_tree . $(function() { $("#project_start_date").datepicker({dateFormat: 'dd-mm-yy'}); }); $(function() { $("#project_end_date").datepicker({dateFormat: 'dd-mm-yy'}); }); jQuery(function(){ jQuery('#start_date_A').datepicker({dateFormat: "dd-mm-yy"}); }); jQuery(function(){ jQuery('#start_date_B').datepicker({dateFormat: "dd-mm-yy"}); }); New View: <div class="start_date" STYLE="text-align: left;"> <b>Start Date:</b> <%= f.text_field :start_date, :class => 'datepicker', :style => 'width: 80px;' %> </div> <div class="end_date" STYLE="text-align: left;"> <b>End Date:</b> <%= f.text_field :end_date, :class => 'datepicker', :style => 'width: 80px;' %> </div> Search View: Start dates between <%= text_field_tag :start_date_A, params[:start_date_A], :style => 'width: 80px;' %> - <%= text_field_tag :start_date_B, params[:start_date_B], :style => 'width: 80px;' %></br> I tried following examples online to get this to work by doing this in the application.js file: $(function() { $("#project_start_date,#project_end_date").datepicker({dateFormat: 'dd-mm-yy'}); }); jQuery(function(){ jQuery('#start_date_A,#start_date_B').datepicker({dateFormat: "dd-mm-yy"}); }); But then the script doesn't run. I am new to rails and javascript so any help at all is appreciated. Thanks in advance. UPDATE: Don't know why my question has been voted to be closed. It's quite simple: I need an error to flag up when the user tries to enter an end date that is before the start date. How can I do that??

    Read the article

  • How would you implement this "WorkerChain" functionality in .NET?

    - by Dan Tao
    Sorry for the vague question title -- not sure how to encapsulate what I'm asking below succinctly. (If someone with editing privileges can think of a more descriptive title, feel free to change it.) The behavior I need is this. I am envisioning a worker class that accepts a single delegate task in its constructor (for simplicity, I would make it immutable -- no more tasks can be added after instantiation). I'll call this task T. The class should have a simple method, something like GetToWork, that will exhibit this behavior: If the worker is not currently running T, then it will start doing so right now. If the worker is currently running T, then once it is finished, it will start T again immediately. GetToWork can be called any number of times while the worker is running T; the simple rule is that, during any execution of T, if GetToWork was called at least once, T will run again upon completion (and then if GetToWork is called while T is running that time, it will repeat itself again, etc.). Now, this is pretty straightforward with a boolean switch. But this class needs to be thread-safe, by which I mean, steps 1 and 2 above need to comprise atomic operations (at least I think they do). There is an added layer of complexity. I have need of a "worker chain" class that will consist of many of these workers linked together. As soon as the first worker completes, it essentially calls GetToWork on the worker after it; meanwhile, if its own GetToWork has been called, it restarts itself as well. Logically calling GetToWork on the chain is essentially the same as calling GetToWork on the first worker in the chain (I would fully intend that the chain's workers not be publicly accessible). One way to imagine how this hypothetical "worker chain" would behave is by comparing it to a team in a relay race. Suppose there are four runners, W1 through W4, and let the chain be called C. If I call C.StartWork(), what should happen is this: If W1 is at his starting point (i.e., doing nothing), he will start running towards W2. If W1 is already running towards W2 (i.e., executing his task), then once he reaches W2, he will signal to W2 to get started, immediately return to his starting point and, since StartWork has been called, start running towards W2 again. When W1 reaches W2's starting point, he'll immediately return to his own starting point. If W2 is just sitting around, he'll start running immediately towards W3. If W2 is already off running towards W3, then W2 will simply go again once he's reached W3 and returned to his starting point. The above is probably a little convoluted and written out poorly. But hopefully you get the basic idea. Obviously, these workers will be running on their own threads. Also, I guess it's possible this functionality already exists somewhere? If that's the case, definitely let me know!

    Read the article

  • Between/Timerange LINQ

    - by dezza
    My intention here is to select all entries (Bookings) between "begin" (begin_prefix) and "end" (end_prefix) BUT! The important thing is: If I have a booking at 07:25-10:00 - you query for 09:00-10:00 it should still show the booking because it reserves the room until 10 no matter what .. So .. 07.25-10.00 booking means query for 09:00-10.00 still returns a list of bookings within 09:00-10.00 (which means 07.25-10.00 is included) public static List<booking> Today(DateTime begin, DateTime end) { try { IFormatProvider Culturez = new CultureInfo(ConfigurationManager.AppSettings["locale"].ToString(), true); DateTime begin_prefix = DateTime.ParseExact(begin.ToString(), "dd-MM-yyyy HH:mm:ss", Culturez); DateTime end_prefix = DateTime.ParseExact(end.ToString(), "dd-MM-yyyy HH:mm:ss", Culturez); dbDataContext db = new dbDataContext(); // gives bookings BEFORE begin_prefix (why?) IQueryable<booking> bQ = from b in db.bookings where begin_prefix >= b.Starts && b.Ends <= end_prefix && b.Ends > b.Starts && b.pointsbookings.Count > 0 select b; // ^gives bookings BEFORE begin_prefix (why?) List<booking> bL = bQ.ToList(); return bL; } catch (Exception) { throw; } } I've tried getting this right for some time now .. Seems everytime I correct it to something new, a new overlap or selection outside the two begin/end dates seem to appear :( UPDATE CRITERIA and SOURCE: Bookings has to be WITHIN "begin_prefix" and "end_prefix" or on the exact same time .. .. currently the above code gives me bookings BEFORE begin_prefix date, which is not intentioned! We're in 2011, I got bookings from 2010 as well! ** NEW!! UPDATED: This is what I have: SEARCH.START = BOOKING.START BOOKING.END <= SEARCH.END ... the problem comes up when .. BOOKING entry: 10:00(Start)-14:00(End) This means according to above: 08.59 = 10.00 (SEARCH.START = BOOKING.START) It will never include it. But it should, since this is the same room and the seats are booked individually!

    Read the article

  • Race condition for thread startup

    - by Ozzah
    A similar question was asked here, but the answers generally all seem to relate to the lambda notation. I get a similar result without the lambda so I thought I'd ask for some clarification: Say I have something like this: for (int i = 0; i < 5; i++) (new Thread(new ThreadStart(delegate() { Console.WriteLine("Thread " + i); }))).Start(); One would expect the following output: Thread 0 Thread 1 Thread 2 Thread 3 Thread 4 Now I realise that the threads aren't started in any particular order, so let's just assume that the above lines can come out in any order. But that is not what happens. What instead happens: Thread 3 Thread 4 Thread 4 Thread 4 Thread 4 or something similar, which leads me to believe that rather than passing the value if i, it is passing the reference. (Which is weird, since an int is a value type). Doing something like this: for (int i = 0; i < 5; i++) (new Thread(new ThreadStart(delegate() { int j = i; Console.WriteLine("Thread " + j); }))).Start(); does not help either, even though we have made a copy of i. I am assuming the reason is that it hasn't made a copy of i in time. Doing something like this: for (int i = 0; i < 5; i++) { (new Thread(new ThreadStart(delegate() { Console.WriteLine("Thread " + i); }))).Start(); Thread.Sleep(50); } seems to fix the problem, however it is extremely undesirable as we're wasting 50ms on each iteration, not to mention the fact that if the computer is heavily loaded then maybe 50ms may not be enough. Here is a sample with my current, specific problem: Thread t = new Thread(new ThreadStart(delgate() { threadLogic(param1, param2, param3, param4); })); t.Start(); param1 = param2 = param3 = param4 = null; with: void threadLogic(object param1, object param2, object param3, object param4) { // Do some stuff here... } I want threadLogic() to run in its own thread, however the above code gives a null reference exception. I assume this is because the values are set to null before the thread has had a chance to start. Again, putting a Thread.Sleep(100) works, but it is an awful solution from every aspect. What do you guys recommend for this particular type of race condition?

    Read the article

  • Should we use temporary variables for the returned values of functions?

    - by totymedli
    I thought about this: Is there a performance difference in these two practices: Store the return value of a function in a temporary variable than give that variable as a parameter to another function. Put the function into the other function. Specification Assuming all classes and functions are written correctly. Case 1. ClassA a = function1(); ClassB b = function2(a); function3(b); Case 2. function3(function2(function1())); I know there aren't a big difference with only one run, but supposed that we could run this a lot of times in a loop, I created some tests. Test #include <iostream> #include <ctime> #include <math.h> using namespace std; int main() { clock_t start = clock(); clock_t ends = clock(); // Case 1. start = clock(); for (int i=0; i<10000000; i++) { double a = cos(1); double b = pow(a, 2); sqrt(b); } ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; // Case 2. start = clock(); for (int i=0; i<10000000; i++) sqrt(pow(cos(1),2)); ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; return 0; } Results Case 1 = 6.375 Case 2 = 0.031 Why is the first one is much slower, and if the second one is faster why dont we always write code that way? Anyway does the second pratice has a name? I also wondered what happens if I create the variables outside the for loop in the first case, but the result was the same. Why?

    Read the article

  • How solve consumer/producer task using semaphores

    - by user1074896
    I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

    Read the article

  • Terminating a long-executing thread and then starting a new one in response to user changing parameters via UI in an applet

    - by user1817170
    I have an applet which creates music using the JFugue API and plays it for the user. It allows the user to input a music phrase which the piece will be based on, or lets them choose to have a phrase generated randomly. I had been using the following method (successfully) to simply stop and start the music, which runs in a thread using the Player class from JFugue. I generate the music using my classes and user input from the applet GUI...then... private playerThread pthread; private Thread threadPlyr; private Player player; (from variables declaration) public void startMusic(Pattern p) // pattern is a JFugue object which holds the generated music { if (pthread == null) { pthread = new playerThread(); } else { pthread = null; pthread = new playerThread(); } if (threadPlyr == null) { threadPlyr = new Thread(pthread); } else { threadPlyr = null; threadPlyr = new Thread(pthread); } pthread.setPattern(p); threadPlyr.start(); } class playerThread implements Runnable // plays midi using jfugue Player { private Pattern pt; public void setPattern(Pattern p) { pt = p; } @Override public void run() { try { player.play(pt); // takes a couple mins or more to execute resetGUI(); } catch (Exception exception) { } } } And the following to stop music when user presses the stop/start button while Player.isPlaying() is true: public void stopMusic() { threadPlyr.interrupt(); threadPlyr = null; pthread = null; player.stop(); } Now I want to implement a feature which will allow the user to change parameters while the music is playing, create an updated music pattern, and then play THAT pattern. Basically, the idea is to make it simulate "real time" adjustments to the generated music for the user. Well, I have been beating my head against the wall on this for a couple of weeks. I've read all the standard java documentation, researched, read, and searched forums, and I have tried many different ideas, none of which have succeeded. The problem I've run into with all approaches I've tried is that when I start the new thread with the new, updated musical pattern, all the old threads ALSO start, and there is a cacophony of unintelligible noise instead of my desired output. From what I've gathered, the issue seems to be that all the methods I've come across require that the thread is able to periodically check the value of a "flag" variable and then shut itself down from within its "run" block in response to that variable. However, since my thread makes a call that takes several minutes minimum to execute (playing the music), and I need to terminate it WHILE it is executing this, there is really no safe way to do so. So, I'm wondering if there is something I'm missing when it comes to threads, or if perhaps I can accomplish my goal using a totally different approach. Any ideas or guidance is greatly appreciated! Thank you!

    Read the article

  • SQLAuthority News – Guest Post – Performance Counters Gathering using Powershell

    - by pinaldave
    Laerte Junior Laerte Junior has previously helped me personally to resolve the issue with Powershell installation on my computer. He did awesome job to help. He has send this another wonderful article regarding performance counter for readers of this blog. I really liked it and I expect all of you who are Powershell geeks, you will like the same as well. As a good DBA, you know that our social life is restricted to a few movies over the year and, when possible, a pizza in a restaurant next to your company’s place, of course. So what we have to do is to create methods through which we can facilitate our daily processes to go home early, and eventually have a nice time with our family (and not sleeping on the couch). As a consultant or fixed employee, one of our daily tasks is to monitor performance counters using Perfmom. To be honest, IDE is getting more complicated. To deal with this, I thought a solution using Powershell. Yes, with some lines of Powershell, you can configure which counters to use. And with one more line, you can already start collecting data. Let’s see one scenario: You are a consultant who has several clients and has just closed another project in troubleshooting an SQL Server environment. You are to use Perfmom to collect data from the server and you already have its XML configuration files made with the counters that you will be using- a file for memory bottleneck f, one for CPU, etc. With one Powershell command line for each XML file, you start collecting. The output of such a TXT file collection is set to up in an SQL Server. With two lines of command for each XML, you make the whole process of data collection. Creating an XML configuration File to Memory Counters: Get-PerfCounterCategory -CategoryName "Memory" | Get-PerfCounterInstance  | Get-PerfCounterCounters |Save-ConfigPerfCounter -PathConfigFile "c:\temp\ConfigfileMemory.xml" -newfile Creating an XML Configuration File to Buffer Manager, counters Page lookups/sec, Page reads/sec, Page writes/sec, Page life expectancy: Get-PerfCounterCategory -CategoryName "SQLServer:Buffer Manager" | Get-PerfCounterInstance | Get-PerfCounterCounters -CounterName "Page*" | Save-ConfigPerfCounter -PathConfigFile "c:\temp\BufferManager.xml" –NewFile Then you start the collection: Set-CollectPerfCounter -DateTimeStart "05/24/2010 08:00:00" -DateTimeEnd "05/24/2010 22:00:00" -Interval 10 -PathConfigFile c:\temp\ConfigfileMemory.xml -PathOutputFile c:\temp\ConfigfileMemory.txt To let the Buffer Manager collect, you need one more counters, including the Buffer cache hit ratio. Just add a new counter to BufferManager.xml, omitting the new file parameter Get-PerfCounterCategory -CategoryName "SQLServer:Buffer Manager" | Get-PerfCounterInstance | Get-PerfCounterCounters -CounterName "Buffer cache hit ratio" | Save-ConfigPerfCounter -PathConfigFile "c:\temp\BufferManager.xml" And start the collection: Set-CollectPerfCounter -DateTimeStart "05/24/2010 08:00:00" -DateTimeEnd "05/24/2010 22:00:00" -Interval 10 -PathConfigFile c:\temp\BufferManager.xml -PathOutputFile c:\temp\BufferManager.txt You do not know which counters are in the Category Buffer Manager? Simple! Get-PerfCounterCategory -CategoryName "SQLServer:Buffer Manager" | Get-PerfCounterInstance | Get-PerfCounterCounters Let’s see one output file as shown below. It is ready to bulk insert into the SQL Server. As you can see, Powershell makes this process incredibly easy and fast. Do you want to see more examples? Visit my blog at Shell Your Experience You can find more about Laerte Junior over here: www.laertejuniordba.spaces.live.com www.simple-talk.com/author/laerte-junior www.twitter.com/laertejuniordba SQL Server Powershell Extension Team: http://sqlpsx.codeplex.com/ Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Add-On, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology Tagged: Powershell

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 142 143 144 145 146 147 148 149 150 151 152 153  | Next Page >