Search Results

Search found 9002 results on 361 pages for 'parent child'.

Page 180/361 | < Previous Page | 176 177 178 179 180 181 182 183 184 185 186 187  | Next Page >

  • Solving embarassingly parallel problems using Python multiprocessing

    - by gotgenes
    How does one use multiprocessing to tackle embarrassingly parallel problems? Embarassingly parallel problems typically consist of three basic parts: Read input data (from a file, database, tcp connection, etc.). Run calculations on the input data, where each calculation is independent of any other calculation. Write results of calculations (to a file, database, tcp connection, etc.). We can parallelize the program in two dimensions: Part 2 can run on multiple cores, since each calculation is independent; order of processing doesn't matter. Each part can run independently. Part 1 can place data on an input queue, part 2 can pull data off the input queue and put results onto an output queue, and part 3 can pull results off the output queue and write them out. This seems a most basic pattern in concurrent programming, but I am still lost in trying to solve it, so let's write a canonical example to illustrate how this is done using multiprocessing. Here is the example problem: Given a CSV file with rows of integers as input, compute their sums. Separate the problem into three parts, which can all run in parallel: Process the input file into raw data (lists/iterables of integers) Calculate the sums of the data, in parallel Output the sums Below is traditional, single-process bound Python program which solves these three tasks: #!/usr/bin/env python # -*- coding: UTF-8 -*- # basicsums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file. """ import csv import optparse import sys def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) return cli_parser def parse_input_csv(csvfile): """Parses the input CSV and yields tuples with the index of the row as the first element, and the integers of the row as the second element. The index is zero-index based. :Parameters: - `csvfile`: a `csv.reader` instance """ for i, row in enumerate(csvfile): row = [int(entry) for entry in row] yield i, row def sum_rows(rows): """Yields a tuple with the index of each input list of integers as the first element, and the sum of the list of integers as the second element. The index is zero-index based. :Parameters: - `rows`: an iterable of tuples, with the index of the original row as the first element, and a list of integers as the second element """ for i, row in rows: yield i, sum(row) def write_results(csvfile, results): """Writes a series of results to an outfile, where the first column is the index of the original row of data, and the second column is the result of the calculation. The index is zero-index based. :Parameters: - `csvfile`: a `csv.writer` instance to which to write results - `results`: an iterable of tuples, with the index (zero-based) of the original row as the first element, and the calculated result from that row as the second element """ for result_row in results: csvfile.writerow(result_row) def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # gets an iterable of rows that's not yet evaluated input_rows = parse_input_csv(in_csvfile) # sends the rows iterable to sum_rows() for results iterable, but # still not evaluated result_rows = sum_rows(input_rows) # finally evaluation takes place as a chain in write_results() write_results(out_csvfile, result_rows) infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) Let's take this program and rewrite it to use multiprocessing to parallelize the three parts outlined above. Below is a skeleton of this new, parallelized program, that needs to be fleshed out to address the parts in the comments: #!/usr/bin/env python # -*- coding: UTF-8 -*- # multiproc_sums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file, using multiple processes if desired. """ import csv import multiprocessing import optparse import sys NUM_PROCS = multiprocessing.cpu_count() def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) cli_parser.add_option('-n', '--numprocs', type='int', default=NUM_PROCS, help="Number of processes to launch [DEFAULT: %default]") return cli_parser def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # Parse the input file and add the parsed data to a queue for # processing, possibly chunking to decrease communication between # processes. # Process the parsed data as soon as any (chunks) appear on the # queue, using as many processes as allotted by the user # (opts.numprocs); place results on a queue for output. # # Terminate processes when the parser stops putting data in the # input queue. # Write the results to disk as soon as they appear on the output # queue. # Ensure all child processes have terminated. # Clean up files. infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) These pieces of code, as well as another piece of code that can generate example CSV files for testing purposes, can be found on github. I would appreciate any insight here as to how you concurrency gurus would approach this problem. Here are some questions I had when thinking about this problem. Bonus points for addressing any/all: Should I have child processes for reading in the data and placing it into the queue, or can the main process do this without blocking until all input is read? Likewise, should I have a child process for writing the results out from the processed queue, or can the main process do this without having to wait for all the results? Should I use a processes pool for the sum operations? If yes, what method do I call on the pool to get it to start processing the results coming into the input queue, without blocking the input and output processes, too? apply_async()? map_async()? imap()? imap_unordered()? Suppose we didn't need to siphon off the input and output queues as data entered them, but could wait until all input was parsed and all results were calculated (e.g., because we know all the input and output will fit in system memory). Should we change the algorithm in any way (e.g., not run any processes concurrently with I/O)?

    Read the article

  • Silverlight Verticle Slide Panel

    - by Grant Archibald
    Can anyone recommend a good Silverlight 2.0 slide panel that takes an unknown number of user controls as childen and allows the user to scroll up and down through the child list. Similar to http://www.thejamesbondmovies.com/ but vertical and not just limited to images.

    Read the article

  • Control flex application from embedded Flash control

    - by aip.cd.aish
    I have a flex application and have embedded a flash (SWF) file into it using <mx:SWFLoader>. There is an "Exit" button on the Flash file. I want to be able to handle the button click event on the flex application. So when that button in the flash file is clicked, I want to perform an action in the parent flex application. How can I do this? Thanks!

    Read the article

  • How to use CWnd::CreateEx

    - by chitra
    I was using CreateEx( 0, className, "XXX", WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN, rect, parent, 0); in Visual C++ 6.0. when i port the same to VS 2008.., its giving an error message saying that.. error C2664: 'BOOL CWnd::CreateEx(DWORD,LPCTSTR,LPCTSTR,DWORD,const RECT &,CWnd *,UINT,LPVOID)' : cannot convert parameter 3 from 'const char [7]' to 'LPCTSTR' how to rectify the same thanks Chitra

    Read the article

  • What is the best way to add and order to Doctrine Nested Set Trees?

    - by murze
    What is the best way to add a sense of order in Doctrine Nested Sets? The documention contains several examples of how to get al the childeren of a specific node $category->getNode()->getSiblings() But how can I for example: change the position of the fourth sibling to the second position get only the second sibling add a sibling between the second and third child etc... Do I have to manually add and ordercolumn to the model to do these operations?

    Read the article

  • Getting XQuery [modify()]: Top-level attribute nodes are not supported error while modifying xml

    - by sam
    DECLARE @mycur CURSOR DECLARE @id int DECLARE @ParentNodeName varchar(max) DECLARE @NodeName varchar(max) DECLARE @NodeText varchar(max) SET @mycur = CURSOR FOR SELECT * FROM @temp OPEN @mycur FETCH NEXT FROM @mycur INTO @id,@ParentNodeName,@NodeName,@NodeText WHILE @@FETCH_STATUS = 0 BEGIN PRINT @id -- sample statements PRINT @ParentNodeName PRINT @NodeName SET @x.modify (' insert attribute status {sql:variable("@status")} as first into (/@ParentNodeName/@NodeName/child::*[position()=sql:variable("@status")])[1] ') FETCH NEXT FROM @mycur INTO @id,@ParentNodeName,@NodeName,@NodeText END DEALLOCATE @mycur Any idea why I am getting this error as query works fine if I manually insert path

    Read the article

  • Creating DNN Portal through Code (or programming) ?

    - by Harryboy
    I have one portal with 3 modules inside it, now my requirement is i would like to create new portal for every client registered in my DNN site. So, i have one interface for registration, so as soon as client registers entirely new parent portal should be created with all the modules. How can i achieve this functionality ???

    Read the article

  • Searching global catalog

    - by Will I Am
    If I do a query (I plan to use SDS.P) against the global catalog, what should the starting path be so I can search the entire GC? I want to enumerate all users in GC, for example. Let's say my gc has users for 3 domains (one parent, two children): TEST.COM ONE.TEST.COM TWO.TEST.COM and i'm on a computer in ONE.TEST.COM. I do not want to hardcode DC=XXX,DC=yyy, I would like to determine that at runtime. TIA! -Will

    Read the article

  • How to insert html in iframe

    - by Massimo Ugues
    Hallo all: I need to insert a html string in a iframe as shown below: .... var html = "<html><head><title>Titolo</title></head><body><p>body</p></body></html>" jQuery('#popolaIframe').click(function() { parent.$("#indexIframe")[0].documentElement.innerHTML = html; }); Is there a way to achieve this? Kind regards Massimo

    Read the article

  • MS Access 2003 - Unbound Form uses INSERT statement to save to table; what about subforms?

    - by Justin
    So I have an unbound form that I use to save data to a table on button click. Is there a way I can have subforms for entry that will allow me to save data to the table within that same button click? Basically I want to add more entry options for the user, and while I know other ways to do it, I am particularly curious about doing it this way (if it can be done). So lets say the 'parent form' is frmMain. And there are two child forms "sub1" and "sub2". Just for example sake lets say on frmMain there are two text boxes: txtTitle & txtAuthor. sub1 and sub2 both have a text Box on them that represent something like prices. The idea is Title & author of a book, and then a price at each store (simplified). So I tried this (because I thought it was worth a shot): Dim db as DAO.database Dim sql as String sql = "INSERT INTO (Title, Author, PriceA, PriceB) VALUES (" if not isnull(me.txtTitle) then sql = sql & """" & me.txtTitle & """," Else sql = sql & " NULL," End If if not IsNull(me.txtAuthor) then sql = sql & " """ & me.txtAuthor & """," else sql = sql & " NULL," end if if not IsNull (forms!sub1.txtPrice) then sql = sql & " """ & forms!sub1.txtPrice & """," else sql = sql & " NULL," end if without finishing the code, i think you may see the GOTCHA i am headed for. I tried this and got an "Access cannot find the form "" ". I think I can pretty much see why on this approach too, because when I click the button that calls the new sub form into the parent form, the values that were just entered are not held/saved as sub1 closes and sub2 opens. I should mention that the idea above is not intended to be a one or the other approach, rather both sub forms used everytime. so this is an example. i want to use this method (if possible) to have about 7 different sub form choices in one form, and be able to save to a table via a SQL statement. I realize that there may be better ways, but I am just wondering if I can get there with this approach out of curiousity. Thanks as always!

    Read the article

  • Why does Android's onItemClick want a long for row Id?

    - by HenryAdamsJr
    For a listView, when you register an OnItemClickListener, the method you specify looks like this: public abstract void onItemClick (AdapterView parent, View view, int position, long id) The id corresponds to the row that the user clicked on. My question is simply why is it a long and not an int? When would you use it as a long? I've been casting it to an int when I use it, so it makes me think that maybe I'm using it wrong.

    Read the article

  • open new window javascript

    - by Midhat
    I have a window.open call in a page, whose window itself is opened by a window.open call. So there are 2 windows already on the screen Now On the next window.open call: IE7 opens a new window Firefox opens a new tab in the topmost parent window Chrome opens a new tab in current window Is it possible to make this behaviour same in all three browsers. (preferably like #3) Edit : my call is rly simple javascript:window.open("Attachment.aspx?docid=42")

    Read the article

  • Universal iPad App rejected because of launch crash that I can't reproduce

    - by Enrique R.
    Hello everyone, I'm very frustrated with this problem. After one week of waiting my universal iPad app has been rejected because "is crashing on launch on iPad running iPhone OS 3.2 and iPhone 3GS running iPhone OS 3.1.3 and Mac OS X 10.6.2." Unfortunately I can't replicate the problem, I've tested in debug and release modes and the app works just fine. I even created an ad-hoc configuration and test it in other devices and everything works fine. I should clarify that this is an update to a current iPhone application and I'm using the same distribution profile as the original iPhone app. Also, I checked everything before building the universal app following this entry: http://iphonedevelopment.blogspot.com/2010/04/converting-iphone-apps-to-universal.html Here are the crash logs that Apple sent me: Incident Identifier: 3E0D4A3B-2896-444D-BCBE-6C0CA1A66A90 CrashReporter Key: 18b5124ea5f657227c5f202a27ed707379b3e2e7 Process: Transfer [982] Path: /var/mobile/Applications/E9062465-7EA6-424C-9C61-D9DBCC7C915A/Transfer.app/Transfer Identifier: Transfer Version: ??? (???) Code Type: ARM (Native) Parent Process: launchd [1] Date/Time: 2010-05-04 15:35:57.399 -0700 OS Version: iPhone OS 3.1.3 (7E18) Report Version: 104 Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x00000001, 0x3eaa2188 Highlighted Thread: 0 Backtrace not available Unknown thread crashed with ARM Thread State: r0: 0x00002f90 r1: 0x00000000 r2: 0x385242d8 r3: 0x0000010d r4: 0x00000000 r5: 0x00000000 r6: 0x00000000 r7: 0x00000000 r8: 0x2ffffba0 r9: 0x2fffef90 r10: 0x00000000 r11: 0x00000000 ip: 0x0000000c sp: 0x2ffffba4 lr: 0x2fe08727 pc: 0x00002f94 cpsr: 0x40000010 Binary Images: 0x1000 - 0x25fff +Transfer armv7 /var/mobile/Applications/E9062465-7EA6-424C-9C61-D9DBCC7C915A/Transfer.app/Transfer 0x2fe00000 - 0x2fe24fff dyld armv7 /usr/lib/dyld .... And the one for the iPad: Incident Identifier: 3B170A28-C8E2-4018-8166-E69432A65070 CrashReporter Key: 4a0194e3f60559127faef2b014df605e4c47b981 Hardware Model: iPad1,1 Process: Transfer [533] Path: /var/mobile/Applications/400EE394-7BEE-45CA-942D-DBDC106360FF/Transfer.app/Transfer Identifier: Transfer Version: ??? (???) Code Type: ARM (Native) Parent Process: launchd [1] Date/Time: 2010-05-04 15:37:17.505 -0700 OS Version: iPhone OS 3.2 (7B367) Report Version: 104 Exception Type: 00000020 Exception Codes: 0x8badf00d Highlighted Thread: 0 Application Specific Information: com.erclab.iphone.photodownload failed to launch in time elapsed total CPU time (seconds): 1.150 (user 0.560, system 0.590), 6% CPU elapsed application CPU time (seconds): 0.150, 1% CPU Thread 0: 0 libobjc.A.dylib 0x33561996 0x33560000 + 6550 1 libobjc.A.dylib 0x33564986 0x33560000 + 18822 2 libobjc.A.dylib 0x33564cb2 0x33560000 + 19634 ... The app does not do anything other than loading a local HTML into a web view after the app it's launched so I don't understand why it says "failed to launch in time" Any help will be very much appreciated.

    Read the article

  • Trouble with inheritance

    - by Matt
    I'm relatively new to programming so excuse me if I get some terms wrong (I've learned the concepts, I just haven't actually used most of them). Trouble: I currently have a class I'll call Bob its parent class is Cody, Cody has method call Foo(). I want Bob to have the Foo() method as well, except with a few extra lines of code. I've attempted to do Foo() : base(), however that doesn't seem to work like. Is there some simple solution to this?

    Read the article

  • What happens when I subscribe to a message using NServiceBus?

    - by Ben Aston
    When I subscribe as the recipient of a certain type of message using NServiceBus Bus.Subscribe<MyMessage>() What am I actually doing? Am I specifying that a particular method on the recipient type will be invoked upon message receipt? If so, within what context does the method run - in a static context, or within the context of a new'd-up parent class instance (and if so, how does NServiceBus know what constructor to use)?

    Read the article

  • Backbone.Marionette - Collection within CompositeView, which itself is nested in a CollectionView

    - by nicefinly
    *UPDATE: The problem probably involves the tour-template as I've discovered that it thinks the 'name' attribute is undefined. This leads me to think that it's not an array being passed on to the ToursView, but for some reason a string. * After studying similar questions on StackOverflow: How to handle nested CompositeView using Backbone.Marionette? How do you properly display a Backbone marionette collection view based on a model javascript array property? Nested collections with Backbone.Marionette ... and Derick Bailey's excellent blog's on this subject: http://lostechies.com/derickbailey/2012/04/05/composite-views-tree-structures-tables-and-more/ ... including the JSFiddle's: http://jsfiddle.net/derickbailey/AdWjU/ I'm still having trouble with a displaying the last node of a nested CollectionView of CompositeViews. It is the final CollectionView within each CompositeView that is causing the problem. CollectionView { CompositeView{ CollectionView {} //**<-- This is the troublemaker!** } } NOTE: I have already made a point of creating a valid Backbone.Collection given that the collection passed on to the final, child CollectionView is just a simple array. Data returned from the api to ToursList: [ { "id": "1", "name": "Venice", "theTours": "[ {'name': u'test venice'}, {'name': u'test venice 2'} ]" }, { "id": "2", "name": "Rome", "theTours": "[ {'name': u'Test rome'} ]" }, { "id": "3", "name": "Dublin", "theTours": "[ {'name': u'test dublin'}, {'name': u'test dublin 2'} ]" } ] I'm trying to nest these in a dropdown where the nav header is the 'name' (i.e. Dublin), and the subsequent li 's are the individual tour names (i.e. 'test dublin', 'test dublin2', etc.) Tour Models and Collections ToursByLoc = TastypieModel.extend({}); ToursList = TastypieCollection.extend({ model: ToursByLoc, url:'/api/v1/location/', }); Tour Views ToursView = Backbone.Marionette.ItemView.extend({ template: '#tour-template', tagName: 'li', }); ToursByLocView = Backbone.Marionette.CompositeView.extend({ template: '#toursByLoc-template', itemView: ToursView, initialize: function(){ //As per Derick Bailey's comments regarding the need to pass on a //valid Backbone.Collection to the child CollectionView //REFERENCE: http://stackoverflow.com/questions/12163118/nested-collections-with-backbone-marionette var theTours = this.model.get('theTours'); this.collection = new Backbone.Collection(theTours); }, appendHtml: function(collectionView, itemView){ collectionView.$('div').append(itemView.el); } }); ToursListView = Backbone.Marionette.CollectionView.extend({ itemView: ToursByLocView, }); Templates <script id="tour-template" type="text/template"> <%= name %> </script> <script id="toursByLoc-template" type="text/template"> <li class="nav-header"><%= name %></li> <div class="indTours"></div> <li class="divider"></li> </script>

    Read the article

  • Key event handling process

    - by backspace7
    I'd like to know how the key event is handled in Android platform. From 'when user type key 'a' on software keyboard', To 'view draw the character 'a' on itself'. Probably, the key event is generated by IME, And it will be sent to parent view, Finally, view(such as EditText) displays chracters. Please somebody explains about these entire key event handling process.

    Read the article

  • How to create custom asp.net validator that works with UpdatePanel?

    - by Goran
    I think that subject summs it pretty well... I have created my custom validators that work great when I put them on page in design mode. However if I place them in a usercontrol, and then try to add this user control to the parent page via updatepanel, then my custom validators just won't trigger. They simply don't work. Does anyone have any clue on what I have to do here? .net 3.5

    Read the article

  • JFace ApplicationWindow: createContents isn't working

    - by jasonh
    I'm attempting to create a window that is divided into three parts. A non-resizable header and footer and then a content area that expands to fill the remaining area in the window. To get started, I created the following class: public class MyWindow extends ApplicationWindow { Color white; Font mainFont; Font headerFont; public MyWindow() { super(null); } protected Control createContents(Composite parent) { Display currentDisplay = Display.getCurrent(); white = new Color(currentDisplay, 255, 255, 255); mainFont = new Font(currentDisplay, "Tahoma", 8, 0); headerFont = new Font(currentDisplay, "Tahoma", 16, 0); // Main layout Composites and overall FillLayout Composite container = new Composite(parent, SWT.NO_RADIO_GROUP); Composite header = new Composite(container, SWT.NO_RADIO_GROUP); Composite mainContents = new Composite(container, SWT.NO_RADIO_GROUP);; Composite footer = new Composite(container, SWT.NO_RADIO_GROUP);; FillLayout containerLayout = new FillLayout(SWT.VERTICAL); container.setLayout(containerLayout); // Header Label headerLabel = new Label(header, SWT.LEFT); headerLabel.setText("Header"); headerLabel.setFont(headerFont); // Main contents Label contentsLabel = new Label(mainContents, SWT.CENTER); contentsLabel.setText("Main Content Here"); contentsLabel.setFont(mainFont); // Footer Label footerLabel = new Label(footer, SWT.CENTER); footerLabel.setText("Footer Here"); footerLabel.setFont(mainFont); return container; } public void dispose() { cleanUp(); } @Override protected void finalize() throws Throwable { cleanUp(); super.finalize(); } private void cleanUp() { if (headerFont != null) { headerFont.dispose(); } if (mainFont != null) { mainFont.dispose(); } if (white != null) { white.dispose(); } } } And this results in an empty window when I run it like this: public static void main(String[] args) { MyWindow myWindow = new MyWindow(); myWindow.setBlockOnOpen(true); myWindow.open(); Display.getCurrent().dispose(); } What am I doing wrong that I don't see three labels the way I'm trying to display them? The createContents code is definitely being called, I can step through it in Eclipse in debug mode.

    Read the article

< Previous Page | 176 177 178 179 180 181 182 183 184 185 186 187  | Next Page >