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  • Help with iphone dev - beyond bounds error

    - by dusk
    I'm just learning iphone development, so please forgive me for what is probably a beginner error. I've searched around and haven't found anything specific to my problem, so hopefully it is an easy fix. The book has examples of building a table from data hard coded via an array. Unfortunately it never really tells you how to get data from a URL, so I've had to look that up and that is where my problems show up. When I debug in xcode, it seems like the count is correct, so I don't understand why it is going out of bounds? This is the error message: 2010-05-03 12:50:42.705 Simple Table[3310:20b] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSCFArray objectAtIndex:]: index (1) beyond bounds (0)' My URL returns the following string: first,second,third,fourth And here is the iphone code with the book's working example commented out #import "Simple_TableViewController.h" @implementation Simple_TableViewController @synthesize listData; - (void)viewDidLoad { /* //working code from book NSArray *array = [[NSArray alloc] initWithObjects:@"Sleepy", @"Sneezy", @"Bashful", @"Bashful", @"Happy", @"Doc", @"Grumpy", @"Thorin", @"Dorin", @"Norin", @"Ori", @"Balin", @"Dwalin", @"Fili", @"Kili", @"Oin", @"Gloin", @"Bifur", @"Bofur", @"Bombur", nil]; self.listData = array; [array release]; */ //code from interwebz that crashes NSString *urlstr = [[NSString alloc] initWithFormat:@"http://www.mysite.com/folder/iphone-test.php"]; NSURL *url = [[NSURL alloc] initWithString:urlstr]; NSString *ans = [NSString stringWithContentsOfURL:url]; NSArray *listItems = [ans componentsSeparatedByString:@","]; self.listData = listItems; [urlstr release]; [url release]; [ans release]; [listItems release]; [super viewDidLoad]; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; self.listData = nil; [super viewDidUnload]; } - (void)dealloc { [listData release]; [super dealloc]; } #pragma mark - #pragma mark Table View Data Source Methods - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [self.listData count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *SimpleTableIdentifier = @"SimpleTableIdentifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:SimpleTableIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SimpleTableIdentifier] autorelease]; } NSUInteger row = [indexPath row]; cell.textLabel.text = [listData objectAtIndex:row]; return cell; } @end

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  • [PHP] Dots and spaces in variable names from external sources are converted to underscores

    - by Brandon
    Trying a bit of AJAX, and I find that much of my data is littered with underscores! Documentation confirms that this is working as intended. Any way to pass my form information to PHP in tact? I'm using code igniter, so my pass looks like /controller/function/variable, receiving controller: controller{ function($v=0){#what once was hello world is now hello_world...} } I can't very well do an undo, data might contain an underscore. Thanks, Brandon

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  • Several numpy arrays with SWIG

    - by Petter
    I am using SWIG to pass numpy arrays from Python to C++ code: %include "numpy.i" %init %{ import_array(); %} %apply (float* INPLACE_ARRAY1, int DIM1) {(float* data, int n)}; class Class { public: void test(float* data, int n) { //... } }; and in Python: c = Class() a = zeros(5) c.test(a) This works, but how can I pass multiple numpy arrays to the same function?

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  • Oracle .dmp file

    - by Grasper
    I have an oracle .dmp file, and no access to an oracle install.. Is there any way I can read the data or open it in another program to see what data is in this file?

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  • What are the benefits of using ORM over XML Serialization/Deserialization?

    - by Tequila Jinx
    I've been reading about NHibernate and Microsoft's Entity Framework to perform Object Relational Mapping against my data access layer. I'm interested in the benefits of having an established framework to perform ORM, but I'm curious as to the performance costs of using it against standard XML Serialization and Deserialization. Right now, I develop stored procedures in Oracle and SQL Server that use XML Types for either input or output parameters and return or shred XML depending on need. I use a custom database command object that uses generics to deserialize the XML results into a specified serializable class. By using a combination of generics, xml (de)serialization and Microsoft's DAAB, I've got a process that's fairly simple to develop against regardless of the data source. Moreover, since I exclusively use Stored Procedures to perform database operations, I'm mostly protected from changes in the data structure. Here's an over-simplified example of what I've been doing. static void main() { testXmlClass test = new test(1); test.Name = "Foo"; test.Save(); } // Example Serializable Class ------------------------------------------------ [XmlRootAttribute("test")] class testXmlClass() { [XmlElement(Name="id")] public int ID {set; get;} [XmlElement(Name="name")] public string Name {set; get;} //create an instance of the class loaded with data. public testXmlClass(int id) { GenericDBProvider db = new GenericDBProvider(); this = db.ExecuteSerializable("myGetByIDProcedure"); } //save the class to the database... public Save() { GenericDBProvider db = new GenericDBProvider(); db.AddInParameter("myInputParameter", DbType.XML, this); db.ExecuteSerializableNonQuery("mySaveProcedure"); } } // Database Handler ---------------------------------------------------------- class GenericDBProvider { public T ExecuteSerializable<T>(string commandText) where T : class { XmlSerializer xml = new XmlSerializer(typeof(T)); // connection and command code is assumed for the purposes of this example. // the final results basically just come down to... return xml.Deserialize(commandResults) as T; } public void ExecuteSerializableNonQuery(string commandText) { // once again, connection and command code is assumed... // basically, just execute the command along with the specified // parameters which have been serialized. } public void AddInParameter(string name, DbType type, object value) { StringWriter w = new StringWriter(); XmlSerializer x = new XmlSerializer(value.GetType()); //handle serialization for serializable classes. if (type == DbType.Xml && (value.GetType() != typeof(System.String))) { x.Serialize(w, value); w.Close(); // store serialized object in a DbParameterCollection accessible // to my other methods. } else { //handle all other parameter types } } } I'm starting a new project which will rely heavily on database operations. I'm very curious to know whether my current practices will be sustainable in a high-traffic situation and whether or not I should consider switching to NHibernate or Microsoft's Entity Framework to perform what essentially seems to boil down to the same thing I'm currently doing. I appreciate any advice you may have.

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  • ComboBox in Flex

    - by Ravi K Chowdary
    Hi, I have a combobox with multi selection. when i click on add button, which ever data is selected in the Combobox, those data has to be displayed in the another comboBox. Please check the code and Can anyone of you please help me on this. "/ Thanks, Ravi

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  • paypal ipn working but stopping at 'thank you' page.

    - by Tarique Imam
    I am using the code for controller(CODEIGNITER): function paypal_tran(){ if (empty($_GET['action'])){ $_GET['action'] = 'process';} if($this-uri-segment ( 3 )){ $action=$this-uri-segment ( 3 ); } else{ $action='process'; } $ammount=39.99; $this-lenders_model-paypal_process($action,$this_script,$ammount); $this-load-view('view_paypal_tran'); } function ipn(){ if ($this->paypal_class->validate_ipn()) { $data = array( 'fname'=> 'fname', /* insert the user id */ 'lname'=>'lname' ); //$this->db->insert('ajax_test',$data); // For this example, we'll just email ourselves ALL the data. $subject = 'Instant Payment Notification - Recieved Payment'; $to = '[email protected]'; // your email $body = "An instant payment notification was successfully recieved\n"; $body .= "from ".$p->ipn_data['payer_email']." on ".date('m/d/Y'); $body .= " at ".date('g:i A')."\n\nDetails:\n"; foreach ($this->paypal_class->ipn_data as $key => $value) { $body .= "\n$key: $value"; } mail($to, $subject, $body); } } function success() { $this->load->view('paypal_succ_view'); } AND this is my model: function paypal_process($action,$this_script,$ammount){ switch ($action) { case 'process': // Process and order... // There should be no output at this point. To process the POST data, // the submit_paypal_post() function will output all the HTML tags which // contains a FORM which is submited instantaneously using the BODY onload // attribute. In other words, don't echo or printf anything when you're // going to be calling the submit_paypal_post() function. // This is where you would have your form validation and all that jazz. // You would take your POST vars and load them into the class like below, // only using the POST values instead of constant string expressions. // For example, after ensureing all the POST variables from your custom // order form are valid, you might have: // // $p->add_field('first_name', $_POST['first_name']); // $p->add_field('last_name', $_POST['last_name']); $this->paypal_class->add_field('business', '[email protected]'); $this->paypal_class->add_field('return', $this_script.'/success'); $this->paypal_class->add_field('cancel_return', $this_script.'/cancel'); $this->paypal_class->add_field('notify_url', $this_script.'/ipn'); $this->paypal_class->add_field('item_name', 'Lenders Account for one month'); $this->paypal_class->add_field('amount', $ammount); $this->paypal_class->submit_paypal_post(); // submit the fields to paypal $this->paypal_class->dump_fields(); // for debugging, output a table of all the fields break; PROBLEM IS IPN IS NOT WORKING. THE HIDDEN FIELD HAS VALUE FOR REDIRECT TO IPN, BUT NOT WORKING!!PLS HELP

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  • problems with passing html to the server with jquery

    - by CoffeeCode
    i have an ajax call $.ajax({ url: '<%=Url.Action("SaveDetails","Survey") %>', dataType: 'JSON', cache: false, data: { Id: selectedRow.Id, Value: surveyValue, FileName: filename, FileGuid: fileguid }, success: function(data) { ... } }); where the surveyValue is a html string. this call doesn't work. but is i change the surveyValue to an ordinary text i works fine. how can i pass the html to the server?

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  • When using delegates, need better way to do sequential processing

    - by Padawan
    I have a class WebServiceCaller that uses NSURLConnection to make asynchronous calls to a web service. The class provides a delegate property and when the web service call is done, it calls a method webServiceDoneWithXXX on the delegate. There are several web service methods that can be called, two of which are say GetSummary and GetList. The classes that use WebServiceCaller initially need both the summary and list so they are written like this: -(void)getAllData { [webServiceCaller getSummary]; } -(void)webServiceDoneWithGetSummary { [webServiceCaller getList]; } -(void)webServiceDoneWithGetList { ... } This works but there are at least two problems: The calls are split across delegate methods so it's hard to see the sequence at a glance but more important it's hard to control or modify the sequence. Sometimes I want to call just GetSummary and not also GetList so I would then have to use an ugly class-level state variable that tells webServiceDoneWithGetSummary whether to call GetList or not. Assume that GetList cannot be done until GetSummary completes and returns some data which is used as input to GetList. Is there a better way to handle this and still get asynchronous calls? Update based on Matt Long's answer: Using notifications instead of a delegate, it looks like I can solve problem #2 by setting a different selector depending on whether I want the full sequence (GetSummary+GetList) or just GetSummary. Both observers would still use the same notification name when calling GetSummary. I would have to write two separate methods to handle GetSummaryDone instead of using a single delegate method (where I would have needed some class-level variable to tell whether to then call GetList). -(void)getAllData { [[NSNotificationCenter defaultCenter] addObserver:self              selector:@selector(getSummaryDoneAndCallGetList:)                  name:kGetSummaryDidFinish object:nil];     [webServiceCaller getSummary]; } -(void)getSummaryDoneAndCallGetList { [NSNotificationCenter removeObserver] //process summary data [[NSNotificationCenter defaultCenter] addObserver:self              selector:@selector(getListDone:)                  name:kGetListDidFinish object:nil];     [webServiceCaller getList]; } -(void)getListDone { [NSNotificationCenter removeObserver] //process list data } -(void)getJustSummaryData { [[NSNotificationCenter defaultCenter] addObserver:self              selector:@selector(getJustSummaryDone:) //different selector but                  name:kGetSummaryDidFinish object:nil]; //same notification name     [webServiceCaller getSummary]; } -(void)getJustSummaryDone { [NSNotificationCenter removeObserver] //process summary data } I haven't actually tried this yet. It seems better than having state variables and if-then statements but you have to write more methods. I still don't see a solution for problem 1.

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  • Cannot use "image.save" on django

    - by zjm1126
    My error is: IOError at /mytest/photo/upload/ [Errno 2] No such file or directory: u'/mytest/photo/upload/2.png' And my view is: UPLOAD_URL = '/mytest/photo/upload/' def upload(request): buf = request.FILES.get('photo', None) print buf if buf: #data = buf.read() #f = StringIO.StringIO(data) image = Image.open(buf) #image = image.convert('RGB') name = '%s%s' % (UPLOAD_URL, buf.name) image.save(file(name, 'wb'), 'PNG') return HttpResponse('ok') return HttpResponse('no') And my urls.py is: urlpatterns = patterns('mytest.views', url(r'^photo/upload/$','upload',name="") ) How can I fix this?

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  • How to approach performance issues?

    - by jess
    Hi, We are developing a client-server desktop application(winforms with sql server 2008, using LINQ-SQL).We are now finding many issues related to performance.These relate to querying too much data with LINQ , bad database design,not much caching etc.What do you suggest,we should do - how to go about solving these performance issues? One thing,I am doing is doing sql profiling,and trying to fix some queries.As far caching is concerned,we have static lists.But,how to keep them updated,we don't have any server side implementation.So,these lists can be stale,if someone changes data. regards

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  • Zend_DB_Table Update problem

    - by davykiash
    Am trying to construct a simple update query in my model class Model_DbTable_Account extends Zend_Db_Table_Abstract { protected $_name = 'accounts'; public function activateaccount($activationcode) { $data = array( 'accounts_status' => 'active', ); $this->update($data, 'accounts_activationkey = ' . $activationcode); } However I get an SQLSTATE[42S22]: Column not found: 1054 Unknown column 'my activation code value' in 'where clause' error. What am I missing in Zend_Table update construct?

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  • Which is the fastest way to move 1Petabyte from one storage to a new one?

    - by marc.riera
    First of all, thanks for reading, and sorry for asking something related to my job. I understand that this is something that I should solve by myself but as you will see its something a bit difficult. A small description: Now Storage = 1PB using DDN S2A9900 storage for the OSTs, 4 OSS , 10 GigE network. (lustre 1.6) 100 compute nodes with 2x Infiniband 1 infiniband switch with 36 ports After Storage = Previous storage + another 1PB using DDN S2A 990 or LSI E5400 (still to decide) (lustre 2.0) 8 OSS , 10GigE network 100 compute nodes with 2x Infiniband Previous experience: transfered 120 TB in less than 3 days using following command: tar -C /old --record-size 2048 -b 2048 -cf - dir | tar -C /new --record-size 2048 -b 2048 -xvf - 2>&1 | tee /tmp/dir.log So , big problem here, using big mathematical equations I conclude that we are going to need 1 month to transfer the data from one side to the new one. During this time the researchers will need to step back, and I'm personally not happy with this. I'm telling you that we have infiniband connections because I think that may be there is a chance to use it to transfer the data using 18 compute nodes (18 * 2 IB = 36 ports) to transfer the data from one storage to the other. I'm trying to figure out if the IB switch will handle all the traffic but in case it just burn up will go faster than using 10GigE. Also, having lustre 1.6 and 2.0 agents on same server works quite well, with this there is no need to go by 1.8 to upgrade the metadata servers with two steps. Any ideas? Many thanks Note 1: Zoredache, we can divide it in two blocks (A)600Tb and (B)400Tb. The idea is to move (A) to new storage which is lustre2.0 formated, then format where (A) was with lustre2.0 and move (B) to this lustre2.0 block and extend with the space where (B) was. This way we will end with (A) and (B) on separate filesystems, with 1PB each.

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  • How does WCF RIA Services handle authentication/authorization/security?

    - by Edward Tanguay
    Since no one answered this question: What issues to consider when rolling your own data-backend for Silverlight / AJAX on non-ASP.NET server? Let me ask it another way: How does WCF RIA Services handle authentication/authorization/security at a low level? e.g. how does the application on the server determine that the incoming http request to change data is coming from a valid client and not from non-desirable source, e.g. a denial-of-service bot?

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  • How to fill byte array with junk?

    - by flyout
    I am using this: byte[] buffer = new byte[10240]; As I understand this initialize the buffer array of 10kb filled with 0s. Whats the fastest way to fill this array (or initialize it) with junk data every time? I need to use that array like 5000 times and fill it every time with different junk data, that's why I am looking for a fast method to do it. The array size will also have to change every time.

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  • SELECT INTO statement in sqlite.

    - by monish
    HI Guys, Here I a wanna know that whether sqlite supports SELECT INTO statement. Actually I am trying to save the data in my table1 into table2 as a backup of my database before modifying the data. for that when I am using the SELECT INTO Statement a syntax error was generating as: My query as: SELECT * INTO equipments_backup FROM equipments; "Last Error Message:near "INTO":syntax error". Anyone's help will be appreciated. Thank you, Monish.

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  • Modifying Export to Excel in ReportViewer

    - by firedrawndagger
    I have a formatted table in ReportViewer. When I want to export to Excel though - I do not want to export the formatted table - instead I want to output the original/raw/unmassaged data table in an excel file. What's the best way to intercept the Export to Excel function and output data in a different format?

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  • How to properly test Hibernate length restriction?

    - by Cesar
    I have a POJO mapped with Hibernate for persistence. In my mapping I specify the following: <class name="ExpertiseArea"> <id name="id" type="string"> <generator class="assigned" /> </id> <version name="version" column="VERSION" unsaved-value="null" /> <property name="name" type="string" unique="true" not-null="true" length="100" /> ... </class> And I want to test that if I set a name longer than 100 characters, the change won't be persisted. I have a DAO where I save the entity with the following code: public T makePersistent(T entity){ transaction = getSession().beginTransaction(); transaction.begin(); try{ getSession().saveOrUpdate(entity); transaction.commit(); }catch(HibernateException e){ logger.debug(e.getMessage()); transaction.rollback(); } return entity; } Actually the code above is from a GenericDAO which all my DAOs inherit from. Then I created the following test: public void testNameLengthMustBe100orLess(){ ExpertiseArea ea = new ExpertiseArea( "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890"); assertTrue("Name should be 100 characters long", ea.getName().length() == 100); ead.makePersistent(ea); List<ExpertiseArea> result = ead.findAll(); assertEquals("Size must be 1", result.size(),1); ea.setName(ea.getName()+"1234567890"); ead.makePersistent(ea); ExpertiseArea retrieved = ead.findById(ea.getId(), false); assertTrue("Both objects should be equal", retrieved.equals(ea)); assertTrue("Name should be 100 characters long", (retrieved.getName().length() == 100)); } The object is persisted ok. Then I set a name longer than 100 characters and try to save the changes, which fails: 14:12:14,608 INFO StringType:162 - could not bind value '12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890' to parameter: 2; data exception: string data, right truncation 14:12:14,611 WARN JDBCExceptionReporter:100 - SQL Error: -3401, SQLState: 22001 14:12:14,611 ERROR JDBCExceptionReporter:101 - data exception: string data, right truncation 14:12:14,614 ERROR AbstractFlushingEventListener:324 - Could not synchronize database state with session org.hibernate.exception.DataException: could not update: [com.exp.model.ExpertiseArea#33BA7E09-3A79-4C9D-888B-4263314076AF] //Stack trace 14:12:14,615 DEBUG GenericDAO:87 - could not update: [com.exp.model.ExpertiseArea#33BA7E09-3A79-4C9D-888B-4263314076AF] 14:12:14,616 DEBUG JDBCTransaction:186 - rollback 14:12:14,616 DEBUG JDBCTransaction:197 - rolled back JDBC Connection That's expected behavior. However when I retrieve the persisted object to check if its name is still 100 characters long, the test fails. The way I see it, the retrieved object should have a name that is 100 characters long, given that the attempted update failed. The last assertion fails because the name is 110 characters long now, as if the ea instance was indeed updated. What am I doing wrong here?

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  • Formatted HTML as output from method invocation from JMX HTTP page

    - by Dutch
    Hi, Is there a way to return HTML from a method which gets called from the JMX HTTP page. I have a huge set of data and want to display the data with some formatting. The following code does not work: @ManagedOperation(description = "return html") @ManagedOperationParameters({@ManagedOperationParameter(name = "someVal", description = "text")}) public List returnAsHtml(String someVal) { return ""+someValblah"; } Looks like JMX escapes the returned script before throwing it to the browser.

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  • Flex 3 file download - Without URLRequest

    - by Srirangan
    Hey guys, My Flex client app has got some data from the back end (RemoteObjects, BlazeDS, Spring). Client has got all the data it needs, it now needs to put some information in a CSV format and make it available for download. Using Flex 3 for this. Any ideas? Thanks, Sri

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  • Accidental Complexity in OpenSSL HMAC functions

    - by Hassan Syed
    SSL Documentation Analaysis This question is pertaining the usage of the HMAC routines in OpenSSL. Since Openssl documentation is a tad on the weak side in certain areas, profiling has revealed that using the: unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, int n, unsigned char *md, unsigned int *md_len); From here, shows 40% of my library runtime is devoted to creating and taking down **HMAC_CTX's behind the scenes. There are also two additional function to create and destroy a HMAC_CTX explicetly: HMAC_CTX_init() initialises a HMAC_CTX before first use. It must be called. HMAC_CTX_cleanup() erases the key and other data from the HMAC_CTX and releases any associated resources. It must be called when an HMAC_CTX is no longer required. These two function calls are prefixed with: The following functions may be used if the message is not completely stored in memory My data fits entirely in memory, so I choose the HMAC function -- the one whose signature is shown above. The context, as described by the man page, is made use of by using the following two functions: HMAC_Update() can be called repeatedly with chunks of the message to be authenticated (len bytes at data). HMAC_Final() places the message authentication code in md, which must have space for the hash function output. The Scope of the Application My application generates a authentic (HMAC, which is also used a nonce), CBC-BF encrypted protocol buffer string. The code will be interfaced with various web-servers and frameworks Windows / Linux as OS, nginx, Apache and IIS as webservers and Python / .NET and C++ web-server filters. The description above should clarify that the library needs to be thread safe, and potentially have resumeable processing state -- i.e., lightweight threads sharing a OS thread (which might leave thread local memory out of the picture). The Question How do I get rid of the 40% overhead on each invocation in a (1) thread-safe / (2) resume-able state way ? (2) is optional since I have all of the source-data present in one go, and can make sure a digest is created in place without relinquishing control of the thread mid-digest-creation. So, (1) can probably be done using thread local memory -- but how do I resuse the CTX's ? does the HMAC_final() call make the CTX reusable ?. (2) optional: in this case I would have to create a pool of CTX's. (3) how does the HMAC function do this ? does it create a CTX in the scope of the function call and destroy it ? Psuedocode and commentary will be useful.

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  • Producer / Consumer - I/O Disk

    - by Pedro Magalhaes
    Hi, I have a compressed file in the disk, that a partitioned in blocks. I read a block from disk decompress it to memory and the read the data. It is possible to create a producer/consumer, one thread that recovers compacted blocks from disk and put in a queue and another thread that decompress and read the data? Will the performance be better? Thanks!

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  • Why do I get rows of zeros in my 2D fft?

    - by Nicholas Pringle
    I am trying to replicate the results from a paper. "Two-dimensional Fourier Transform (2D-FT) in space and time along sections of constant latitude (east-west) and longitude (north-south) were used to characterize the spectrum of the simulated flux variability south of 40degS." - Lenton et al(2006) The figures published show "the log of the variance of the 2D-FT". I have tried to create an array consisting of the seasonal cycle of similar data as well as the noise. I have defined the noise as the original array minus the signal array. Here is the code that I used to plot the 2D-FT of the signal array averaged in latitude: import numpy as np from numpy import ma from matplotlib import pyplot as plt from Scientific.IO.NetCDF import NetCDFFile ### input directory indir = '/home/nicholas/data/' ### get the flux data which is in ### [time(5day ave for 10 years),latitude,longitude] nc = NetCDFFile(indir + 'CFLX_2000_2009.nc','r') cflux_southern_ocean = nc.variables['Cflx'][:,10:50,:] cflux_southern_ocean = ma.masked_values(cflux_southern_ocean,1e+20) # mask land nc.close() cflux = cflux_southern_ocean*1e08 # change units of data from mmol/m^2/s ### create an array that consists of the seasonal signal fro each pixel year_stack = np.split(cflux, 10, axis=0) year_stack = np.array(year_stack) signal_array = np.tile(np.mean(year_stack, axis=0), (10, 1, 1)) signal_array = ma.masked_where(signal_array > 1e20, signal_array) # need to mask ### average the array over latitude(or longitude) signal_time_lon = ma.mean(signal_array, axis=1) ### do a 2D Fourier Transform of the time/space image ft = np.fft.fft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log(mgft) log_mgft= np.log(mgft) Every second row of the ft consists completely of zeros. Why is this? Would it be acceptable to add a randomly small number to the signal to avoid this. signal_time_lon = signal_time_lon + np.random.randint(0,9,size=(730, 182))*1e-05 EDIT: Adding images and clarify meaning The output of rfft2 still appears to be a complex array. Using fftshift shifts the edges of the image to the centre; I still have a power spectrum regardless. I expect that the reason that I get rows of zeros is that I have re-created the timeseries for each pixel. The ft[0, 0] pixel contains the mean of the signal. So the ft[1, 0] corresponds to a sinusoid with one cycle over the entire signal in the rows of the starting image. Here are is the starting image using following code: plt.pcolormesh(signal_time_lon); plt.colorbar(); plt.axis('tight') Here is result using following code: ft = np.fft.rfft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log1p(mgft) plt.pcolormesh(log_ps); plt.colorbar(); plt.axis('tight') It may not be clear in the image but it is only every second row that contains completely zeros. Every tenth pixel (log_ps[10, 0]) is a high value. The other pixels (log_ps[2, 0], log_ps[4, 0] etc) have very low values.

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