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DNS protocol message example

- by virtual-lab

hello there, I am trying to figure out how to send out DNS messages from an application socket adapter to a DNSBL. I spent the last two days understanding the basics, including experimenting with WireShark to catch an example of message exchanged. Now I would like to query the DNS without using dig or host command (I'm using Ubuntu); how can I perform this action at low level, without the help of these tools in wrapping the request in a proper DNS message format? How the message should be post it? Hex or String? Thanks in advance for any help. Regards Alessandro Ilardo Comment added I am investigating on JDev and Oracle SOA. The platform provides a Socket Adapter which simply apply a transformation (XSLT) and send the message straight to the socket. How the payload parameters (ex. the host I'm looking up) are wrapped within the message is left to the developer. So basically I have an idea on how the all DNS message is structured, but rather than put everything on JDev stright away I'd like to make some tests on my own just to make sure I got a valid message format. So, I am not using any specific language (I don't even understand why they moved my question from serverfault) and I don't want to use any tools which would hide part of the message, such as the header. I know they work well btw. I guess this stuff has something to do with packet injection. Someone suggested me to use telnet, but I've only used for SMTP or HTTP, I haven't got a clue on how it works for DNS request. Does it make more sense now?

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XSLT 1.0: restrict entries in a nodeset

- by Mike

Hi, Being relatively new to XSLT I have what I hope is a simple question. I have some flat XML files, which can be pretty big (eg. 7MB) that I need to make 'more hierarchical'. For example, the flat XML might look like this: <D0011> .... .... and it should end up looking like this: <D0011> .... .... I have a working XSLT for this, and it essentially gets a nodeset of all the b elements and then uses the 'following-sibling' axis to get a nodeset of the nodes following the current b node (ie. following-sibling::*[position() =$nodePos]). Then recursion is used to add the siblings into the result tree until another b element is found (I have parameterised it of course, to make it more generic). I also have a solution that just sends the position in the XML of the next b node and selects the nodes after that one after the other (using recursion) via a *[position() = $nodePos] selection. The problem is that the time to execute the transformation increases unacceptably with the size of the XML file. Looking into it with XML Spy it seems that it is the 'following-sibling' and 'position()=' that take the time in the two respective methods. What I really need is a way of restricting the number of nodes in the above selections, so fewer comparisons are performed: every time the position is tested, every node in the nodeset is tested to see if its position is the right one. Is there a way to do that ? Any other suggestions ? Thanks, Mike

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Accessing the value of an input element with XPath in an XSLT

- by asymmetric

Hi! I'm developing a web app that has a button that triggers an XSLT transformation of the document DOM, with a stylesheet fetched via AJAX. Here's a portion of the HTML: <html> <head> <title>Static Javascript-based XMR Form Creator</title> </head> <body> <h1 id="title">Static Javascript-based XMR Form Creator</h1> <div class="opt_block" id="main_opts"> Form name <input type="text" id="form_name" /> Form cols <input type="text" id="form_cols" size="3" maxlength="3" /> </div> <button id="generate">Generate source</button> <textarea rows="20" cols="50" id="xmr_source" ></textarea> </body> Inside the stylesheet, I want to access the value attribute of the first input field, the one with id form_name. The XSLT looks like this: <xsl:template match="/html/body/div[@id = 'main_opts']" > <form> <xsl:attribute name="fname"> <xsl:value-of select="input[@id = 'form_name']/@value" /> </xsl:attribute> </form> </xsl:template> The problem is that the XPath that should do the work: <xsl:value-of select="input[@id = 'form_name']/@value" /> returns nothing. Can anyone help?

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How can I create photo effects in Android?

- by PaulH

I'd like to make an Android app that lets a user apply cool effects to photos taken with the camera. There are already a few out there, I know, but I'd like to try my own hand at one. I'm trying to figure out the best way to implement these effects. Here are some examples from the excellent Vignette app (which I own): http://www.flickr.com/groups/vignetteforandroid/pool/ I have been googling and stack-overflowing, but so far I've mostly found some references to published papers or books. I am ordering this one from Amazon presently - Digital Image Processing: An Algorithmic Introduction using Java After some reading, I think I have a basic understanding of manipulating the RGB values for all the pixels in the image. My main question is how do I come up with a transformation that produces cool effects? By cool effects I mean some like those in the Vignette app or IPhone apps: ToyCamera Polarize I already have quite a bit of experience with Java, and I've made my first app for android already. Any ideas? Thanks in advance.

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Combining XmlWriter objects?

- by Kevin

The way my application is structured, each component generates output as XML and returns an XmlWriter object. Before rendering the final output to the page, I combine all XML and perform an XSL transformation on that object. Below, is a simplified code sample of the application structure. Does it make sense to combine XmlWriter objects like this? Is there a better way to structure my application? The optimal solution would be one where I didn't have to pass a single XmlWriter instance as a parameter to each component. function page1Xml() { $content = new XmlWriter(); $content->openMemory(); $content->startElement('content'); $content->text('Sample content'); $content->endElement(); return $content; } function generateSiteMap() { $sitemap = new XmlWriter(); $sitemap->openMemory(); $sitemap->startElement('sitemap'); $sitemap->startElement('page'); $sitemap->writeAttribute('href', 'page1.php'); $sitemap->text('Page 1'); $sitemap->endElement(); $sitemap->endElement(); return $sitemap; } function output($content) { $doc = new XmlWriter(); $doc->openMemory(); $doc->writePi('xml-stylesheet', 'type="text/xsl" href="template.xsl"'); $doc->startElement('document'); $doc->writeRaw( generateSiteMap()->outputMemory() ); $doc->writeRaw( $content->outputMemory() ); $doc->endElement(); $doc->endDocument(); $output = xslTransform($doc); return $output; } $content = page1Xml(); echo output($content); Update: I may abandon XmlWriter altogether and use DomDocument instead. It is more flexible and it also seemed to perform better (at least on the crude tests I created).

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Cannot open a SQL2000 DTS package I imported into SQL2008

- by RJ

I am running into a problem trying to open a SQL2000 DTS package I imported into SQL2008. I set up a new server and installed a fresh install of SQL2008. The database I need to run is a SQL2000 database. I moved the database over with no problem but there are a few DTS packages that need to run in legacy on SQL2008. I exported the DTS packages I need out of SQL2000 and imported them successfully into SQL2008. My SQL2008 server is x64. I can see the DTS packages under Data Transformation Service in Legacy but when I try to open the package I get this message. "SQL Server 2000 DTS Designer components are required to edit DTS packages. Install the special web download, "SQL Server 2000 DTS Designer components" to use this feature. (Microsoft.SqlServer.DtsObjectExplorerUI)" I downloaded the components and installed them and still get this error. I researched and found an article about this not working on x64 so I have an x86 machine that I installed the SQL2008 tools and tried to open the package from there and got the same error. I have spent days on this and need help. Has anyone run across this and can tell me what to do. If you have solved this problem, please help me out. Thanks.

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Suggestions for a django db structure

- by rh0dium

Hi Say I have the unknown number of questions. For example: Is the sky blue [y/n] What date were your born on [date] What is pi [3.14] What is a large integ [100] Now each of these questions poses a different but very type specific answer (boolean, date, float, int). Natively django can happily deal with these in a model. class SkyModel(models.Model): question = models.CharField("Is the sky blue") answer = models.BooleanField(default=False) class BirthModel(models.Model): question = models.CharField("What date were your born on") answer = models.DateTimeField(default=today) class PiModel(models.Model) question = models.CharField("What is pi") answer = models.FloatField() But this has the obvious problem in that each question has a specific model - so if we need to add a question later I have to change the database. Yuck. So now I want to get fancy - How do a set up a model where by the answer type conversion happens automagically? ANSWER_TYPES = ( ('boolean', 'boolean'), ('date', 'date'), ('float', 'float'), ('int', 'int'), ('char', 'char'), ) class Questions(models.model): question = models.CharField(() answer = models.CharField() answer_type = models.CharField(choices = ANSWER_TYPES) default = models.CharField() So in theory this would do the following: When I build up my views I look at the type of answer and ensure that I only put in that value. But when I want to pull that answer back out it will return the data in the format specified by the answer_type. Example 3.14 comes back out as a float not as a str. How can I perform this sort of automagic transformation? Or can someone suggest a better way to do this? Thanks much!!

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View results of affine transform

- by stckjp

I am trying to find out the reason why when I apply affine transformations on an image in OpenCV, the result of it is not visible in the preview window, but the entire window is black.How can I find workaround for this problem so that I can always view my transformed image (the result of the affine transform) in the window no matter the applied transformation? Update: I think that this happens because all the transformations are calculated with respect to the origin of the coordinate system (top left corner of the image). While for rotation I can specify the center of the rotation, and I am able to view the result, when I perform scaling I am not able to control where the transformed image goes. Is it possible to somehow move the coordinate system to make the image fit in the window? Update2: I have an image which contains only ROI at some position in it (the rest of the image is black), and I need to apply a set of affine transforms on it. To make things simpler and to see the effect of each individual transform, I applied each transform one by one. What I noticed is that, whenever I move (translate) the image such that the center of the ROI is in the center of the coordinate system (top left corner of the view window), all the affine transforms perform correctly without moving. However, by translating the center of ROI at the center of the coordinate system, the upper and the left part of the ROI remain cut out of the current view window. If I move ROI's central point to another point in the view window (for example the window center), an affine transform of type: A=[a 0 0; 0 b 0] (A is 2x3 matrix, parameter of the warpAffine function) moves the image (ROI), outside of the view window (which doesn't happen if the ROI's center is in the top-left corner). How can I modify the affine transform so the image doesn't move out of its place (behaves the same way as when the ROI center is in the center of the coordinate system)?

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Compiler turning a string& into a basic_string<>&

- by Shtong

Hello I'm coming back to C++ after long years spent on other technologies and i'm stuck on some weird behavior when calling some methods taking std::string as parameters : An example of call : LocalNodeConfiguration *LocalNodeConfiguration::ReadFromFile(std::string & path) { // ... throw configuration_file_error(string("Configuration file empty"), path); // ... } When I compile I get this (I cropped file names for readability) : /usr/bin/g++ -g -I/home/shtong/Dev/OmegaNoc/build -I/usr/share/include/boost-1.41.0 -o CMakeFiles/OmegaNocInternals.dir/configuration/localNodeConfiguration.cxx.o -c /home/shtong/Dev/OmegaNoc/source/configuration/localNodeConfiguration.cxx .../localNodeConfiguration.cxx: In static member function ‘static OmegaNoc::LocalNodeConfiguration* OmegaNoc::LocalNodeConfiguration::ReadFromFile(std::string&)’: .../localNodeConfiguration.cxx:72: error: no matching function for call to ‘OmegaNoc::configuration_file_error::configuration_file_error(std::string, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&)’ .../configurationManager.hxx:25: note: candidates are: OmegaNoc::configuration_file_error::configuration_file_error(std::string&, std::string&) .../configurationManager.hxx:22: note: OmegaNoc::configuration_file_error::configuration_file_error(const OmegaNoc::configuration_file_error&) So as I understand it, the compiler is considering that my path parameter turned into a basic_string at some point, thus not finding the constructor overload I want to use. But I don't really get why this transformation happened. Some search on the net suggested me to use g++ but I was already using it. So any other advice would be appreciated :) Thanks

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How can I embed images within my application and use them in HTML control?

- by Atara

Is there any way I can embed the images within my exe (as resource?) and use it in generated HTML ? Here are the requirements: A. I want to show dynamic HTML content (e.g. using webBrowser control, VS 2008, VB .Net, winForm desktop application) B. I want to generate the HTML on-the-fly using XML and XSL (file1.xml or file2.xml transformed by my.xsl) C. The HTML may contain IMG tags (file1.gif and or file2.gif according to the xml+xsl transformation) and here comes the complicated one: D. All these files (file1.xml, file2.xml, my.xsl, file1.gif, file2.gif) should be embedded in one exe file. I guess the XML and XSL can be embedded resources, and I can read them as stream, but what ways do I have to reference the image within the HTML ? <IMG src="???" /> I do not want to use absolute path and external files. If the image files are resources, can I use relative path? Relative to what? (I can use BASE tag, and then what?) Can I use stream as in email messages? If so, where can I find the format I need to use? http://www.websiteoptimization.com/speed/tweak/inline-images/ are browser dependent. What is the browser used by webBrowser control? IE? what version? Does it matter if I use GIF or JPG or BMP (or any other image format) for the images? Does it matter if I use mshtml library and not the regular webBrowser control? (currently I use http://www.itwriting.com/htmleditor/index.php ) Does it matter if I upgrade to VS 2010 ? Thanks, Atara

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XSLT special characters

- by Apurv

In the following XSL transformation how do I output the '<' and '' symbol? Input XML: <TestResult bugnumber="3214" testname="display.methods::close->test_ManyInvoke" errortype="Failure"><ErrorMessage><![CDATA[calling close() method failed - expected:<2>]]></ErrorMessage> XSLT: <xsl:template match="TestResult"> <xsl:variable name="errorMessage"> <xsl:value-of select="ErrorMessage" disable-output-escaping="yes"/> </xsl:variable> <Test name='{@testname}'> <TestResult> <Passed>false</Passed> <State>failure</State> <Metadata> <Entry name='bugnumber' value='{@bugnumber}' /> </Metadata> <TestOutput> <Metadata> <Entry name='ErrorMessage' value='{$errorMessage}' /> </Metadata> </TestOutput> </TestResult> </Test> </xsl:template> Output XML: <Test name="display.methods::close-&gttest_ManyInvoke"> <TestResult> <Passed>false</Passed> <State>failure</State> <Metadata> <Entry name="bugnumber" value="3214"/> </Metadata> <TestOutput> <Metadata> <Entry name="ErrorMessage" value="calling close() method failed - expected:<2>"/> </Metadata> </TestOutput> </TestResult> </Test>

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iPhone: How to use CGContextConcatCTM for saving a transformed image properly?

- by Irene

I am making an iPhone application that loads an image from the camera, and then the user can select a second image from the library, move/scale/rotate that second image, and then save the result. I use two UIImageViews in IB as placeholders, and then apply transformations while touching/pinching. The problem comes when I have to save both images together. I use a rect of the size of the first image and pass it to UIGraphicsBeginImageContext. Then I tried to use CGContextConcatCTM but I can't understand how it works: CGRect rect = CGRectMake(0, 0, img1.size.width, img1.size.height); // img1 from camera UIGraphicsBeginImageContext(rect.size); // Start drawing CGContextRef ctx = UIGraphicsGetCurrentContext(); CGContextClearRect(ctx, rect); // Clear whole thing [img1 drawAtPoint:CGPointZero]; // Draw background image at 0,0 CGContextConcatCTM(ctx, img2.transform); // Apply the transformations of the 2nd image But what do I need to do next? What information is being held in the img2.transform matrix? The documentation for CGContextConcatCTM doesn't help me that much unfortunately.. Right now I'm trying to solve it by calculating the points and the angle using trigonometry (with the help of this answer), but since the transformation is there, there has to be an easier and more elgant way to do this, right?

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Update table using SSIS

- by thursdaysgeek

I am trying to update a field in a table with data from another table, based on a common key. If it were in straight SQL, it would be something like: Update EHSIT set e.IDMSObjID = s.IDMSObjID from EHSIT e, EHSIDMS s where e.SITENUM = s.SITE_CODE However, the two tables are not in the same database, so I'm trying to use SSIS to do the update. Oh, and the sitenum/site_code are varchar in one and nvarchar in the other, so I'll have to do a data conversion so they'll match. How do I do it? I have a data flow object, with the source as EHSIDMS and the destination as EHSIT. I have a data conversion to convert the unicode to non-unicode. But how do I update based on the match? I've tried with the destination, using a SQL Command as the Data Access mode, but it doesn't appear to have the source table. If I just map the field to be updated, how does it limit it based on fields matching? I'm about to export my source table to Excel or something, and then try inputting from there, although it seems that all that would get me would be to remove the data conversion step. Shouldn't there be an update data task or something? Is it one of those Data Flow transformation tasks, and I'm just not figuring out which it is?

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Groupby distinct how can I do that?

- by Christophe Debove

Hello, <?xml version="1.0"?> <Products> <product> <productId >1</productId> <textdate>11/11/2011</textdate> <price>200</price> </product> <product> <productId >6</productId> <textdate>11/11/2011</textdate> <price>100</price> </product> <product> <productId >1</productId> <textdate>16/11/2011</textdate> <price>290</price> </product> </Products> I've this xml and I want an xslt transformation that regroup product something like this : { product 1 : 11/11/2011 - 200 16/11/2011 - 290 } { product 6 11/11/2011 - 100 } I work with xslt 1.0 Asp .net C# XslCompiledTransformation

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Data structure to build and lookup set of integer ranges

- by actual

I have a set of uint32 integers, there may be millions of items in the set. 50-70% of them are consecutive, but in input stream they appear in unpredictable order. I need to: Compress this set into ranges to achieve space efficient representation. Already implemented this using trivial algorithm, since ranges computed only once speed is not important here. After this transformation number of resulting ranges is typically within 5 000-10 000, many of them are single-item, of course. Test membership of some integer, information about specific range in the set is not required. This one must be very fast -- O(1). Was thinking about minimal perfect hash functions, but they do not play well with ranges. Bitsets are very space inefficient. Other structures, like binary trees, has complexity of O(log n), worst thing with them that implementation make many conditional jumps and processor can not predict them well giving poor performance. Is there any data structure or algorithm specialized in integer ranges to solve this task?

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How to ignore the validation of Unknown tags ?

- by infant programmer

One more challenge to the XSD capability,I have been sending XML files by my clients, which will be having 0 or more undefined or [call] unexpected tags (May appear in hierarchy). Well they are redundant tags for me .. so I have got to ignore their presence, but along with them there are some set of tags which are required to be validated. This is a sample XML: <root> <undefined_1>one</undefined_1> <undefined_2>two</undefined_2> <node>to_be_validated</node> <undefined_3>two</undefined_3> <undefined_4>two</undefined_4> </root> And the XSD I tried with: <xs:element name="root" type="root"></xs:element> <xs:complexType name="root"> <xs:sequence> <xs:any maxOccurs="2" minOccurs="0"/> <xs:element name="node" type="xs:string"/> <xs:any maxOccurs="2" minOccurs="0"/> </xs:sequence> </xs:complexType XSD doesn't allow this, due to certain reasons. The above mentioned example is just a sample. The practical XML comes with the complex hierarchy of XML tags .. Kindly let me know if you can get a hack of it. By the way, The alternative solution is to insert XSL-transformation, before validation process. Well, I am avoiding it because I need to change the .Net code which triggers validation process, which is supported at the least by my company.

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Concept: Information Into Memory Location.

- by Richeve S. Bebedor

I am having troubles conceptualizing an algorithm to be used to transform any information or data into a specific appropriate and reasonable memory location in any data structure that I will be devising. To give you an idea, I have a JPanel object instance and I created another Container type object instance of any subtype (note this is in Java because I love this language), then I collected those instances into a data structure not specifically just for those instances but also applicable to any type of object. Now my procedure for fetching those data again is to extract the object specific features similar in category to all object in that data structure and transform it into a integer data memory location (specifically as much as possible) or any type of data that will pertain to this transformation. And I can already access that memory location without further sorting or applications of O(n) time complex algorithms (which I think preferable but I wanted to do my own way XD). The data structure is of any type either binary tree, linked list, arrays or sets (and the like XD). What is important is I don't need to have successive comparing and analysis of data just to locate information in big structures. To give you a technical idea, I have to an array DS that contains JLabel object instance with a specific name "HelloWorld". But array DS contains other types of object (in multitude). Now this JLabel object has a location in the array at index [124324] (which is if you do any type of searching algorithm just to arrive at that location is conceivably slow because added to it the data structure used was an array *note please disregard the efficiency of the data structure to be used I just want to explain to you my concept XD). Now I want to equate "HelloWorld" to 124324 by using a conceptually made function applicable to all data types. So that I can do a direct search by doing this DS[extractLocation("HelloWorld")] just to get that JLabel instance. I know this may sound crazy but I want to test my concept of non-sorting feature extracting search algorithm for any data structure wherein my main problem is how to transform information to be stored into memory location of where it was stored.

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A beginner question on passthru() function in PHP

- by Robert

Hi all, I've used the following code to do an XSLT translation in PHP and save the result SVG file into a sub folder: $command = $java . $saxon . $target2 . ' ' . $xsl2.' '.$param; ob_start(); passthru($command, $result); $content_grabbed=ob_get_contents(); ob_end_clean(); $info = pathinfo($_FILES['file']['name']); $file_name= basename($_FILES['file']['name'],'.'.$info['extension']); $myFile = "images/convert/".$file_name."_".$_POST["mydropdown"].".svg"; $fh = fopen($myFile, 'w') or die("can't open file"); fwrite($fh, $content_grabbed); fclose($fh); It does a very simple SVG to SVG transformation, and created the resulting SVG file. the $command is just a simple java -jar saxon.jar input.xml stylesheet java command. The current situation is ,the file gets created perfectly, however, the error gets shown in browser, probably because I inserted the "ob_start" before passthru() command. I am thinking of making use of an argument that comes with the saxon.jar, that is "-o output_file_name". Because the final purpose is not to display the resulting SVG to the browser, but instead creating an SVG file ,and provide the link to the user for downloading. Are there any better ways to handle this problem, I am still thinking about how to get rid of the result that gets shown in the browser that is sent by the "passthru()". Thanks in advance for suggestions!

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why my iphone device and simulator has different screen resolution?

- by happyzone8

i use itouch 4G has my device and i use simulator-4.2 i will just draw a rectangle as an example. i use Quartz-2d to draw - (void)drawRect:(CGRect)rect { // Get a graphics context, saving its state CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSaveGState(context); // Reset the transformation CGAffineTransform t0 = CGContextGetCTM(context); t0 = CGAffineTransformInvert(t0); CGContextConcatCTM(context,t0); // Draw a green rectangle CGContextBeginPath(context); CGContextSetRGBFillColor(context, 0,1,0,1); CGContextAddRect(context, CGRectMake(0,0,320,480)); CGContextClosePath(context); CGContextDrawPath(context,kCGPathFill); CGContextRestoreGState(context); } i run it in the simulator, the whole screen becomes green, then i run this on my device, only the quarter of the screen becomes green, in order to make the whole screen green on my device, i have to draw a larger rectangle CGContextAddRect(context, CGRectMake(0,0,640,960)); seem like my device has twice resolution than the simulator, how can i fix this?

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Saving and restoring OpenGL model-view

- by Tom

I am a new-comer to OpenGL, and much of it remains mysterious to my feeble brain. I have been studying the NeHe demos as well as the Red Book. I am writing an Android application that displays the Earth in the center of the screen. The user can rotate the Earth about any axis (much like a very simple "Google Earth"). This code is working (I based it on the NeHe examples). Now I want to add a feature; the user should be able to save the current model orientation, then later return to that same orientation. For example, the user may save the Earth orientation such that the viewer is looking down at her hometown, and north-east is "up". How do I do this with OpenGL-ES? To capture and save the current orientation, my code could get the current model-view transformation matrix - I think I understand how to do that. But later on how do I apply that saved matrix to restore the view?

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Handling nulls in Datawarehouse

- by rrydman

I'd like to ask your input on what the best practice is for handling null or empty data values when it pertains to data warehousing and SSIS/SSAS. I have several fact and dimension tables that contain null values in different rows. Specifics: 1) What is the best way to handle null date/times values? Should I make a 'default' row in my time or date dimensions and point SSIS to the default row when there is a null found? 2) What is the best way to handle nulls/empty values inside of dimension data. Ex: I have some rows in an 'Accounts' dimensions that have empty (not NULL) values in the Account Name column. Should I convert these empty or null values inside the column to a specific default value? 3) Similar to point 1 above - What should I do if I end up with a Facttable row that has no record in one of the dimension columns? Do I need default dimension records for each dimension in case this happens? 4) Any suggestion or tips in regards to how to handle these operation in Sql server integration services (SSIS)? Best data flow configurations or best transformation objects to use would be helpful. Thanks :-)

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ReplaceAll not working as expected

- by Tim Kemp

Still early days with Mathematica so please forgive what is probably a very obvious question. I am trying to generate some parametric plots. I have: ParametricPlot[{ (a + b) Cos[t] - h Cos[(a + b)/b t], (a + b) Sin[t] - h Sin[(a + b)/b t]}, {t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1} No joy: the replacement rules are not applied and a, b and h remain undefined. If I instead do: Hold@ParametricPlot[{ (a + b) Cos[t] - h Cos[(a + b)/b t], (a + b) Sin[t] - h Sin[(a + b)/b t]}, {t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1} it looks like the rules ARE working, as confirmed by the output: Hold[ParametricPlot[{(2 + 1) Cos[t] - 1 Cos[(2 + 1) t], (2 + 1) Sin[t] - 1 Sin[(2 + 1) t]}, {t, 0, 2 \[Pi]}, PlotRange -> All]] Which is what I'd expect. Take the Hold off, though, and the ParametricPlot doesn't work. There's nothing wrong with the equations or the ParametricPlot itself, though, because I tried setting values for a, b and h in a separate expression (a=2; b=1; h=1) and I get my pretty double cardoid out as expected. So, what am I doing wrong with ReplaceAll and why are the transformation rules not working? This is another fundamentally important aspect of MMA that my OOP-ruined brain isn't understanding. I tried reading up on ReplaceAll and ParametricPlot and the closest clue I found was that "ParametricPlot has attribute HoldAll and evaluates f only after assigning specific numerical values to variables" which didn't help much or I wouldn't be here. Thanks.

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How do I manipulate the format on a DataGridView that is bound to a Data Source?

- by Jack Johnstone

I´m using SQL Server 2005 and Visual Studio 2008, C#. In the data source (the SQL Server data table) I use the DateTime format mm/dd/yyyy, however, in a forms overview (DataGridView) users would like to see a completely other format, with year, week number and day number of week (yyww,d) which is in string format. I´ve created an algorithm for the transformation between values (date to weekday), but can I populate the affected cells with yyww,d (string) instead of mm/dd/yyyy (DateTime)? This is what I´ve been testing out, without success (and note, it´s on the last line the problem becomes obvious, as the cell value won´t accept a string on runtime - it still wants to be a DateTime...) private void DataGridViewQueryFindRequests_CellFormatting( object sender, DataGridViewCellFormattingEventArgs e) { string weekAndDay = ""; DataGridViewCell cell = DataGridViewQueryFindRequests.Rows[e.RowIndex].Cells[e.ColumnIndex]; if (cell.ColumnIndex == 13 && cell.Value == null) mEmptyRow = true; if ((cell.ColumnIndex == 14 || cell.ColumnIndex == 15) && !mEmptyRow) { weekAndDay = ClassWeeksAndDates.dateToWeekNumber(Convert.ToDateTime(cell.Value)); cell.ValueType = typeof(string); cell.Value = weekAndDay; } }

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Const Discards Qualifers: C++

- by user991673

I'm using OpenGL to render camera perspectives, and a one point in my code I'm trying to take the direction of the light (shown here as type "Vector4") and multiply it by a matrix of type "Matrix4x4" that represents the Modelview transformation (sorry if this is not making any sense, this is for a school project, as such I'm still learning about this stuff) Anyway, my code goes as follows... Vector4 lightDirection = data->dir * follow->getModelviewMatrix().getInverse().getTranspose(); data->dir = lightDirection; setLight(*data); this give me the following error: passing 'const vec4<double>' as 'this' argument of 'vec4<T>& vec4<T>::operator=(const vec4<T>&)[with T = double]' discards qualifiers Again, much of this code is prewritten for the class (namely the vector and matrix types) but if someone could just help me decipher what the error means it would be much appreciated! I can give more information as needed. I figured 'data' or 'data-dir' were const, however I can find no mention of either of them to be. 'dir' is of type SceneLightData, and when its added on I'm doing this: void Scene::addLight(const SceneLightData &sceneLight) { SceneLightData light = sceneLight; m_lights.push_back(&light); } The error occurs on this line: data->dir = lightDirection; EDIT problem solved. thanks everyone! solution: void Scene::addLight(const SceneLightData &sceneLight) { SceneLightData* light = new SceneLightData; *light = sceneLight; m_lights.push_back(light); } and SceneLightData* data = m_lights[i]; data->dir = data->dir * follow->getModelviewMatrix().getInverse().getTranspose(); setLight(*data);

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How to process more that one XML document in XSLT?

- by brain_pusher

Is there any trick to match two XML by one XSLT? I mean the way I can apply XSLT to a parameter passed. For example (I missed declarations to be short). XML1: XML to be transformed: <myData> <Collection> </Collection> </myData> XSLT need to be applied to the previous XML: <xsl:param name='items' /> <xsl:template match='Collection'>  </xsl:template> XML2: XML data passed as the parameter 'items': <newData> <Item>1</Item> <Item>2</Item> <Item>3</Item> </newData> And I need to create a set of nodes in the 'Collection' node in XML1 for each 'Item' element in XML2 using XSLT. And I do not know what XML2 contains exactly at design time. It is generated at runtime, so I can't place it inside XSLT, I know only its schema.

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