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  • Invalid BOOT.INI (dual boot XP with 7)

    - by Muxa
    I had Windows XP x64 as my main system, and i also had a second partition with Windows XP x64. Both booted from first partition (C:) I then installed Windows 7 Ultimate on the first partition. I've added NTLDR using BCDRDIT. I've also copied NTLDR, NTDETECT.COM and BOOT.INI onto the drive where XP remained. However then i try to boot into Windows XP x64 i get Invalid BOOT.INI file Booting from c:\windows\ NTDETECT failed I found instructions on how to fix it using a boot disk, however the partitions are on a software RAID. I've tried to boot from a customized XP CD with the drivers, however it does not offer me a Repair option for some reason - just setup. Partitions that i have:'= System Reserved Main (Windows 7) Secondary (Windows XP x64) Here's the contents of my BOOT.INI: [boot loader] timeout=30 default=multi(0)disk(0)rdisk(0)partition(3)\WINDOWS [operating systems] multi(0)disk(0)rdisk(0)partition(3)\WINDOWS="Windows XP Professional x64 Edition" /fastdetect

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  • Mutli-processor workstation as a workstation/server

    - by posdef
    I work in a research institute and a number of programs we use are computationally intensive (I actually wrote one of them). Right now we have one computer that is dedicated for one of these programs (with local accounts only, as in users physically sitting in front of that pc) and the other programs are run on individual workstations assigned to people. I have been looking around to common brands such as Dell and HP, for a some sort of a small/medium scale server, which can be used as a workhorse by sending tasks remotely. It appears as if there is nothing in between workstations with one 6-core processor and a bunch of extras (like fancy graphics etc) and rack mount servers with ridiculous amount of RAM and HDD expansion capabilities but still relatively little number of processors/cores. I wonder if what I am looking for is such a small niche product? Are there other solutions that I might not be aware of? Does anyone know of a multi proc- multi-core workstation/server that is still within the reasonable

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  • Java: micro-optimizing array manipulation

    - by Martin Wiboe
    Hello all, I am trying to make a Java port of a simple feed-forward neural network. This obviously involves lots of numeric calculations, so I am trying to optimize my central loop as much as possible. The results should be correct within the limits of the float data type. My current code looks as follows (error handling & initialization removed): /** * Simple implementation of a feedforward neural network. The network supports * including a bias neuron with a constant output of 1.0 and weighted synapses * to hidden and output layers. * * @author Martin Wiboe */ public class FeedForwardNetwork { private final int outputNeurons; // No of neurons in output layer private final int inputNeurons; // No of neurons in input layer private int largestLayerNeurons; // No of neurons in largest layer private final int numberLayers; // No of layers private final int[] neuronCounts; // Neuron count in each layer, 0 is input // layer. private final float[][][] fWeights; // Weights between neurons. // fWeight[fromLayer][fromNeuron][toNeuron] // is the weight from fromNeuron in // fromLayer to toNeuron in layer // fromLayer+1. private float[][] neuronOutput; // Temporary storage of output from previous layer public float[] compute(float[] input) { // Copy input values to input layer output for (int i = 0; i < inputNeurons; i++) { neuronOutput[0][i] = input[i]; } // Loop through layers for (int layer = 1; layer < numberLayers; layer++) { // Loop over neurons in the layer and determine weighted input sum for (int neuron = 0; neuron < neuronCounts[layer]; neuron++) { // Bias neuron is the last neuron in the previous layer int biasNeuron = neuronCounts[layer - 1]; // Get weighted input from bias neuron - output is always 1.0 float activation = 1.0F * fWeights[layer - 1][biasNeuron][neuron]; // Get weighted inputs from rest of neurons in previous layer for (int inputNeuron = 0; inputNeuron < biasNeuron; inputNeuron++) { activation += neuronOutput[layer-1][inputNeuron] * fWeights[layer - 1][inputNeuron][neuron]; } // Store neuron output for next round of computation neuronOutput[layer][neuron] = sigmoid(activation); } } // Return output from network = output from last layer float[] result = new float[outputNeurons]; for (int i = 0; i < outputNeurons; i++) result[i] = neuronOutput[numberLayers - 1][i]; return result; } private final static float sigmoid(final float input) { return (float) (1.0F / (1.0F + Math.exp(-1.0F * input))); } } I am running the JVM with the -server option, and as of now my code is between 25% and 50% slower than similar C code. What can I do to improve this situation? Thank you, Martin Wiboe

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  • How can I make this Java code run faster?

    - by Martin Wiboe
    Hello all, I am trying to make a Java port of a simple feed-forward neural network. This obviously involves lots of numeric calculations, so I am trying to optimize my central loop as much as possible. The results should be correct within the limits of the float data type. My current code looks as follows (error handling & initialization removed): /** * Simple implementation of a feedforward neural network. The network supports * including a bias neuron with a constant output of 1.0 and weighted synapses * to hidden and output layers. * * @author Martin Wiboe */ public class FeedForwardNetwork { private final int outputNeurons; // No of neurons in output layer private final int inputNeurons; // No of neurons in input layer private int largestLayerNeurons; // No of neurons in largest layer private final int numberLayers; // No of layers private final int[] neuronCounts; // Neuron count in each layer, 0 is input // layer. private final float[][][] fWeights; // Weights between neurons. // fWeight[fromLayer][fromNeuron][toNeuron] // is the weight from fromNeuron in // fromLayer to toNeuron in layer // fromLayer+1. private float[][] neuronOutput; // Temporary storage of output from previous layer public float[] compute(float[] input) { // Copy input values to input layer output for (int i = 0; i < inputNeurons; i++) { neuronOutput[0][i] = input[i]; } // Loop through layers for (int layer = 1; layer < numberLayers; layer++) { // Loop over neurons in the layer and determine weighted input sum for (int neuron = 0; neuron < neuronCounts[layer]; neuron++) { // Bias neuron is the last neuron in the previous layer int biasNeuron = neuronCounts[layer - 1]; // Get weighted input from bias neuron - output is always 1.0 float activation = 1.0F * fWeights[layer - 1][biasNeuron][neuron]; // Get weighted inputs from rest of neurons in previous layer for (int inputNeuron = 0; inputNeuron < biasNeuron; inputNeuron++) { activation += neuronOutput[layer-1][inputNeuron] * fWeights[layer - 1][inputNeuron][neuron]; } // Store neuron output for next round of computation neuronOutput[layer][neuron] = sigmoid(activation); } } // Return output from network = output from last layer float[] result = new float[outputNeurons]; for (int i = 0; i < outputNeurons; i++) result[i] = neuronOutput[numberLayers - 1][i]; return result; } private final static float sigmoid(final float input) { return (float) (1.0F / (1.0F + Math.exp(-1.0F * input))); } } I am running the JVM with the -server option, and as of now my code is between 25% and 50% slower than similar C code. What can I do to improve this situation? Thank you, Martin Wiboe

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  • How to move/drag multiple images with CALayer???

    - by gbf.sara
    I have more than 10 images in screen and i want to move each image using CALayer concept. While am trying to move first image,its working. Even when i drag my second image also, its working. But after that when i get back to first image and when i try to move , am struck up. its not working. I dono where it went wrong. Here's ma code //Assigning Layer to UIImage// layer = [CALayer layer]; UIImage *image1 = [UIImage imageNamed:[NSString stringWithFormat:@"%@_thumb.png",[tiv imageName]]]; layer.contents = (id)image1.CGImage; layer.position=CGPointMake(200,200); layer.frame = CGRectMake(110, 180, 100, 100); [self.view.layer addSublayer:layer]; [layer needsDisplay]; [self.view.layer needsDisplay]; [layer needsLayout]; //Here i try to move my image// - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { [super touchesMoved:touches withEvent:event]; NSArray *allTouches = [touches allObjects]; int count = [allTouches count]; if (count == 1) { if (CGRectContainsPoint([layer frame], [[allTouches objectAtIndex:0] locationInView:self.view])) { layer.position = [[allTouches objectAtIndex:0] locationInView:self.view]; return; } } if (count > 1) { if (CGRectContainsPoint([layer frame], [[allTouches objectAtIndex:-1] locationInView:self.view])) { layer.position = [[allTouches objectAtIndex:0] locationInView:self.view]; return; } } } Also ive planned to use single CALayer for multiple images.. When i click an image, it should be placed in that CALayer and when i click another, the same CALayer should take the latter one. So tat whenever i drag an image it should move(no matter how many images r there) . Do u think this concept will work out or is there any other idea??? My concept may seems to be a basic one. Am new to this environment n so kindly help me..

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  • Testing for Adjacent Cells In a Multi-level Grid

    - by Steve
    I'm designing an algorithm to test whether cells on a grid are adjacent or not. The catch is that the cells are not on a flat grid. They are on a multi-level grid such as the one drawn below. Level 1 (Top Level) | - - - - - | | A | B | C | | - - - - - | | D | E | F | | - - - - - | | G | H | I | | - - - - - | Level 2 | -Block A- | -Block B- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | | -Block D- | -Block E- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | . . . . . . This diagram is simplified from my actual need but the concept is the same. There is a top level block with many cells within it (level 1). Each block is further subdivided into many more cells (level 2). Those cells are further subdivided into level 3, 4 and 5 for my project but let's just stick to two levels for this question. I'm receiving inputs for my function in the form of "A8, A9, B7, D3". That's a list of cell Ids where each cell Id has the format (level 1 id)(level 2 id). Let's start by comparing just 2 cells, A8 and A9. That's easy because they are in the same block. private static RelativePosition getRelativePositionInTheSameBlock(String v1, String v2) { RelativePosition relativePosition; if( v1-v2 == -1 ) { relativePosition = RelativePosition.LEFT_OF; } else if (v1-v2 == 1) { relativePosition = RelativePosition.RIGHT_OF; } else if (v1-v2 == -BLOCK_WIDTH) { relativePosition = RelativePosition.TOP_OF; } else if (v1-v2 == BLOCK_WIDTH) { relativePosition = RelativePosition.BOTTOM_OF; } else { relativePosition = RelativePosition.NOT_ADJACENT; } return relativePosition; } An A9 - B7 comparison could be done by checking if A is a multiple of BLOCK_WIDTH and whether B is (A-BLOCK_WIDTH+1). Either that or just check naively if the A/B pair is 3-1, 6-4 or 9-7 for better readability. For B7 - D3, they are not adjacent but D3 is adjacent to A9 so I can do a similar adjacency test as above. So getting away from the little details and focusing on the big picture. Is this really the best way to do it? Keeping in mind the following points: I actually have 5 levels not 2, so I could potentially get a list like "A8A1A, A8A1B, B1A2A, B1A2B". Adding a new cell to compare still requires me to compare all the other cells before it (seems like the best I could do for this step is O(n)) The cells aren't all 3x3 blocks, they're just that way for my example. They could be MxN blocks with different M and N for different levels. In my current implementation above, I have separate functions to check adjacency if the cells are in the same blocks, if they are in separate horizontally adjacent blocks or if they are in separate vertically adjacent blocks. That means I have to know the position of the two blocks at the current level before I call one of those functions for the layer below. Judging by the complexity of having to deal with mulitple functions for different edge cases at different levels and having 5 levels of nested if statements. I'm wondering if another design is more suitable. Perhaps a more recursive solution, use of other data structures, or perhaps map the entire multi-level grid to a single-level grid (my quick calculations gives me about 700,000+ atomic cell ids). Even if I go that route, mapping from multi-level to single level is a non-trivial task in itself.

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  • Yii: Multi-language website - best practices.

    - by michal
    Hi, I find Yii great framework, and the example website created with yiic shell is a good point to start... however it doesn't cover the topic of multi-language websites, unfortunately. The docs covers the topic of translating short messages, but not keeping the multi-lingual content ... I'm about to start working on a website which needs to be in at least two languages, and I'm wondering what is the best way to keep content for that ... The problem is that the content is mixed extensively with common elements (like embedded video files). I need to avoid duplicating those commons ... so far I used to have an array of arrays containing texts (usually no more than 1-2 short paragraphs), then the view file was just rendering the text from an array. Now I'd like to avoid keeping it in arrays (which requires some attention when putting double quotations " " and is inconvenient in general...). So, what is the best way to keep those short paragraphs? Should I keep them in DB like (id | msg_id | language | content ) and then select them by msg_id & language? That still requires me to create some msg_id's and embed them into view file ... Is there any recommended paradigm for which Yii has some solutions? Thanks, m.

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  • C# XMLRPC Multi Threaded newPost something is not right

    - by user1047463
    I recently decided to get my feet wet with c# multi threading and my progress was good until now. My program uses XML-RPC to create new posts on wordpress. When I run my app on the localhost everything works fine and i successfully able to create new posts on wordpress using a multi threaded approach. However when I try to do the same with a wordpress installed on a remote server , new posts won't appear, so when i go to see all posts, the total number of posts remains unchanged. Another thing to note is the function that creates a new post does return the ID of a supposedly created posts. But as I mentioned previously the new posts are not visible when I try to access them in admin menu. Since I'm new to the multithreading I was hoping some of you guys can help me and check if I'm doing anything wrong. Heres the code that creates threads and calls create post function. foreach (DataRow row in dt.Rows) { Thread t = null; t = new Thread(createPost); lock (t) { t.Start(); } } public void createPost() { string postid; try { icp = (IcreatePost)XmlRpcProxyGen.Create(typeof(IcreatePost)); clientProtocol = (XmlRpcClientProtocol)icp; clientProtocol.Url = xmlRpcUrl; postid = icp.NewPost(1, blogLogin, blogPass, newBlogPost, 1); currentThread--; threadCountLabel.Invoke(new MethodInvoker(delegate { threadCountLabel.Text = currentThread.ToString(); })); } catch (Exception ex) { MessageBox.Show( createPost ERROR ->" + ex.Message); } }

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  • SQL Server - Multi-Column substring matching

    - by hamlin11
    One of my clients is hooked on multi-column substring matching. I understand that Contains and FreeText search for words (and at least in the case of Contains, word prefixes). However, based upon my understanding of this MSDN book, neither of these nor their variants are capable of searching substrings. I have used LIKE rather extensively (Select * from A where A.B Like '%substr%') Sample table A: ID | Col1 | Col2 | Col3 | ------------------------------------- 1 | oklahoma | colorado | Utah | 2 | arkansas | colorado | oklahoma | 3 | florida | michigan | florida | ------------------------------------- The following code will give us row 1 and row 2: select * from A where Col1 like '%klah%' or Col2 like '%klah%' or Col3 like '%klah%' This is rather ugly, probably slow, and I just don't like it very much. Probably because the implementations that I'm dealing with have 10+ columns that need searched. The following may be a slight improvement as code readability goes, but as far as performance, we're still in the same ball park. select * from A where (Col1 + ' ' + Col2 + ' ' + Col3) like '%klah%' I have thought about simply adding insert, update, and delete triggers that simply add the concatenated version of the above columns into a separate table that shadows this table. Sample Shadow_Table: ID | searchtext | --------------------------------- 1 | oklahoma colorado Utah | 2 | arkansas colorado oklahoma | 3 | florida michigan florida | --------------------------------- This would allow us to perform the following query to search for '%klah%' select * from Shadow_Table where searchtext like '%klah%' I really don't like having to remember that this shadow table exists and that I'm supposed to use it when I am performing multi-column substring matching, but it probably yields pretty quick reads at the expense of write and storage space. My gut feeling tells me there there is an existing solution built into SQL Server 2008. However, I don't seem to be able to find anything other than research papers on the subject. Any help would be appreciated.

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  • Django's post_save signal behaves weirdly with models using multi-table inheritance

    - by hekevintran
    Django's post_save signal behaves weirdly with models using multi-table inheritance I am noticing an odd behavior in the way Django's post_save signal works when using a model that has multi-table inheritance. I have these two models: class Animal(models.Model): category = models.CharField(max_length=20) class Dog(Animal): color = models.CharField(max_length=10) I have a post save callback called echo_category: def echo_category(sender, **kwargs): print "category: '%s'" % kwargs['instance'].category post_save.connect(echo_category, sender=Dog) I have this fixture: [ { "pk": 1, "model": "animal.animal", "fields": { "category": "omnivore" } }, { "pk": 1, "model": "animal.dog", "fields": { "color": "brown" } } ] In every part of the program except for in the post_save callback the following is true: from animal.models import Dog Dog.objects.get(pk=1).category == u'omnivore' # True When I run syncdb and the fixture is installed, the echo_category function is run. The output from syncdb is: $ python manage.py syncdb --noinput Installing json fixture 'initial_data' from '~/my_proj/animal/fixtures'. category: '' Installed 2 object(s) from 1 fixture(s) The weird thing here is that the dog object's category attribute is an empty string. Why is it not 'omnivore' like it is everywhere else? As a temporary (hopefully) workaround I reload the object from the database in the post_save callback: def echo_category(sender, **kwargs): instance = kwargs['instance'] instance = sender.objects.get(pk=instance.pk) print "category: '%s'" % instance.category post_save.connect(echo_category, sender=Dog) This works but it is not something I like because I must remember to do it when the model inherits from another model and it must hit the database again. The other weird thing is that I must do instance.pk to get the primary key. The normal 'id' attribute does not work (I cannot use instance.id). I do not know why this is. Maybe this is related to the reason why the category attribute is not doing the right thing?

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  • using Autofac in a multi-layered architecture

    - by Kamyar
    I'm fairly new to the DI/IoC concept and would like to use Autofac in a 3-layered ASP.NET Webforms application. UI layer: An ASP.NET webforms website. BLL: Business logic layer which calls the repositories on DAL. DAL: .EDMX file (Entity Model) and ObjectContext with Repository classes which abstract the CRUD operations for each entity. Entities: The POCO Entities. Persistence Ignorant. Generated by Microsoft's ADO.Net POCO Entity Generator. I have asked a more general question here. Basically, I'd like to create an obejctcontext per HttpContext in my DAL. But i don't want to add a reference to DAL in UI or access to HttpContext in DAL directly. I guess this is where IoC tools come to play. The answer to my previous question is a very good example of using Windsor Castle. I'd like to use Autofac as my IoC tool and Don't know how to achieve this. (How to access DAL in application_start to register the component while I don't want to reference it in my UI, what are the proper references to be able to use DAL component in BLL with Autofac, Should I register BLL as a component with Autofac too) Sorry folks for not providing an explicit question and requesting a kind of working example, But I'm very unfamiliar to the whole IoC concept and I don't think I can achieve it to use in my current time-limited project.

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  • SQL Server Multi-statement UDF - way to store data temporarily required

    - by Kharlos Dominguez
    Hello, I have a relatively complex query, with several self joins, which works on a rather large table. For that query to perform faster, I thus need to only work with a subset of the data. Said subset of data can range between 12 000 and 120 000 rows depending on the parameters passed. More details can be found here: http://stackoverflow.com/questions/3054843/sql-server-cte-referred-in-self-joins-slow As you can see, I was using a CTE to return the data subset before, which caused some performance problems as SQL Server was re-running the Select statement in the CTE for every join instead of simply being run once and reusing its data set. The alternative, using temporary tables worked much faster (while testing the query in a separate window outside the UDF body). However, when I tried to implement this in a multi-statement UDF, I was harshly reminded by SQL Server that multi-statement UDFs do not support temporary tables for some reason... UDFs do allow table variables however, so I tried that, but the performance is absolutely horrible as it takes 1m40 for my query to complete whereas the the CTE version only took 40minutes. I believe the table variables is slow for reasons listed in this thread: http://stackoverflow.com/questions/1643687/table-variable-poor-performance-on-insert-in-sql-server-stored-procedure Temporary table version takes around 1 seconds, but I can't make it into a function due to the SQL Server restrictions, and I have to return a table back to the caller. Considering that CTE and table variables are both too slow, and that temporary tables are rejected in UDFs, What are my options in order for my UDF to perform quickly? Thanks a lot in advance.

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  • multi-part identifier could not be bound error

    - by vishal Shah
    Here is my query: IF OBJECT_ID('NPWAS1513.dbo.usp_MSPEX_QLK_Billing_Fact_Load') IS NOT NULL DROP PROCEDURE dbo.usp_MSPEX_QLK_Billing_Fact_Load; GO CREATE PROCEDURE usp_MSPEX_QLK_Billing_Fact_Load @create_timestamp datetime, @update_timestamp datetime, @create_user varchar(50), @update_user varchar(50), @dbProdServ varchar(50) AS print 'dbProdServ is:'+ @dbProdServ; print 'current_user is:' +@current_user; DECLARE @sSQL AS VARCHAR(MAX); SET @sSQL = '' SET @sSQL = 'set identity_insert ' + @dbProdServ + '.mspex_qlk_billing_fact ON' EXEC(@sSQL); SET @sSQL = 'INSERT INTO ' + @dbProdServ +'.mspex_qlk_billing_fact (project_id, billing_year, billing_month, billing_month_desc, billing_date_id, projected_bill_amount, billed_year_to_date_amount, billed_inception_to_date_amount, remaining_bill_amount, actual_billed_amount, current_billing_percent, previous_billing_percent, billing_pct_diff, billing_type, final_bill_ind, last_in_progress_date, current_record_ind, load_time_stamp, total_contract_period, contract_period_current_year, partial_bill, create_timestamp, create_user, update_timestamp, update_user) SELECT project_dim.project_id, billing_final_data.billingyear, billing_final_data.billingmonth, billing_final_data.billingmonthdesc, Time_Dim.Time_ID, billing_final_data.projected_bill_amount, billing_final_data.billed_year_todate_amount, billing_final_data.billed_inception_todate_amount, billing_final_data.remaining_bill_amount, billing_final_data.actual_billed_amount, billing_final_data.current_billing_percent, billing_final_data.previous_billing_percent, billing_final_data.billing_pct_diff, billing_final_data.billing_type, billing_final_data.final_bill_ind, billing_final_data.last_in_progress_date, billing_final_data.current_record_ind, billing_final_data.load_time_stamp, billing_final_data.[Total Contract Period], billing_final_data.[Contract Period Current Year], billing_final_data.[Partial Bill],'''+ CAST(@create_timestamp as varchar(max)) + ''',''' + @create_user + ''','''+ CAST(@update_timestamp as varchar(50)) +''','''+ @update_user + ''' FROM '+ @dbProdServ +'.mspex_qlk_project_dim project_dim,'+ @dbProdServ +'.mspex_rpt_billing_final_data billing_final_data,'+ @dbProdServ + '.MSPEX_QLK_Time_Dim Time_Dim WHERE project_dim.myproject_project_uid = billing_final_data.projectuid AND'''+ convert(datetime, cast(billing_final_data.[BillingMonth] as nvarchar(2)) + '''/01/''' + cast(billing_final_data.[billingyear] as nvarchar(4)), 101) +''' + = Time_Dim.Time_Date'; BEGIN TRANSACTION EXEC(@sSQL) COMMIT TRANSACTION I get the error msg: Msg 4104, Level 16, State 1, Procedure usp_MSPEX_QLK_Billing_Fact_Load, Line 23 The multi-part identifier "mspex_rpt_billing_final_data.BillingMonth" could not be bound. Msg 4104, Level 16, State 1, Procedure usp_MSPEX_QLK_Billing_Fact_Load, Line 23 The multi-part identifier "billing_final_data.billingyear" could not be bound. Msg 207, Level 16, State 1, Procedure usp_MSPEX_QLK_Billing_Fact_Load, Line 83 Invalid column name 'BillingMonth'. Msg 207, Level 16, State 1, Procedure usp_MSPEX_QLK_Billing_Fact_Load, Line 84 Invalid column name 'billingyear'. I checked the column names, etc. and things are fine. In fact, I directly dragged the table name and column name to ensure that it is correct. Please help ASAP. Calling me at cell at 630-338-9427 would be great. But an URGENT response is absolutely necessary. Thanks guys.

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  • In .NET, What Is Fastest Way to Initialize Multi-Dimensional Array to Non-Default Value

    - by AMissico
    How do I initialize a multi-dimensional array of a primitive type as fast as possible? I am stuck with using multi-dimensional arrays. My problem is performance. The following routine initializes a 100x100 array in approx. 500 ticks. Removing the int.MaxValue initialization results in approx. 180 ticks just for the looping. Approximately 100 ticks to create the array without looping and without initializing to int.MaxValue. Routines similiar to this are called a few tens-of-thousands to several million times. I am open to suggestions on how to optimize this non-default initialization of an array. One idea I had is to use a smaller primitive type when available. For instance, using byte instead of int, saves 100 ticks. I would be happy with this, but I am hoping that I don't have to change the primitive data type. public int[,] CreateArray(Size size) { int[,] array = new int[size.Width, size.Height]; for (int x = 0; x < size.Width; x++) { for (int y = 0; y < size.Height; y++) { array[x, y] = int.MaxValue; } } return array; }

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  • Partially constructed object / Multi threading

    - by reto
    Heya! I'm using joda due to it's good reputation regarding multi threading. It goes great distances to make multi threaded date handling efficient, for example by making all Date/Time/DateTime objects immutable. But here's a situation where I'm not sure if Joda is really doing the right thing. It probably is correct, but I'd be very interested to see the explanation for it. When a toString() of a DateTime is being called Joda does the following: /* org.joda.time.base.AbstractInstant */ public String toString() { return ISODateTimeFormat.dateTime().print(this); } All formatters are thread safe, as they are as well ready-only. But what's about the formatter-factory: private static DateTimeFormatter dt; /* org.joda.time.format.ISODateTimeFormat */ public static DateTimeFormatter dateTime() { if (dt == null) { dt = new DateTimeFormatterBuilder() .append(date()) .append(tTime()) .toFormatter(); } return dt; } This is a common pattern in single threaded applications. I see the following dangers: Race condition during null check -- worst case: two objects get created. No Problem, as this is solely a helper object (unlike a normal singleton pattern situation), one gets saved in dt, the other is lost and will be garbage collected sooner or later. the static variable might point to a partially constructed object before the objec has been finished initialization (before calling me crazy, read about a similar situation in this Wikipedia article. So how does Joda ensure that not partially created formatter gets published in this static variable? Thanks for your explanations! Reto

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  • Maven3 Issues with building a multi-module enterprise project

    - by Sujit K
    I just migrated from Maven2 to Maven3 and I'm able to build each module individually or all the modules in one shot by calling mvn clean install. However, in Maven2, since we have multi-module enterprise project, we build multiple ear's and each ear is built as its own module with its own child pom. To build an individual ear with its dependents, the below command works fine in Maven2 but not in Maven3. Let me explain the issue in Maven3 a bit later. mvn -pl ear_module -rf first_dependent_module -am clean install In Maven2 when the reactor lists the build order, I see first_dependent_module second_dependent_module ear_module End of the day I have my ear module also part of the reactor which is how it should be. The reason we call -rf is we don't want to delete the target folder at the main ${project.basedir} (so not to delete the output created in target from building the other ear modules). With Maven3, however, this is all I see when the reactor lists the build order: first_dependent_module second_dependent_module Maven3 totally ignores the argument (ear_module) set to -pl flag to be also built after its dependents have been. Not sure what I'm missing here. Any help/tips would be greatly appreciated. P.S: The build I'm making is similar to the one below.... Build specific module in multi-module project Thanks, SK

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  • MS SQL - Multi-Column substring matching

    - by hamlin11
    One of my clients is hooked on multi-column substring matching. I understand that Contains and FreeText search for words (and at least in the case of Contains, word prefixes). However, based upon my understanding of this MSDN book, neither of these nor their variants are capable of searching substrings. I have used LIKE rather extensively (Select * from A where A.B Like '%substr%') Sample table A: ID | Col1 | Col2 | Col3 | ------------------------------------- 1 | oklahoma | colorado | Utah | 2 | arkansas | colorado | oklahoma | 3 | florida | michigan | florida | ------------------------------------- The following code will give us row 1 and row 2: select * from A where Col1 like '%klah%' or Col2 like '%klah%' or Col3 like '%klah%' This is rather ugly, probably slow, and I just don't like it very much. Probably because the implementations that I'm dealing with have 10+ columns that need searched. The following may be a slight improvement as code readability goes, but as far as performance, we're still in the same ball park. select * from A where (Col1 + ' ' + Col2 + ' ' + Col3) like '%klah%' I have thought about simply adding insert, update, and delete triggers that simply add the concatenated version of the above columns into a separate table that shadows this table. Sample Shadow_Table: ID | searchtext | --------------------------------- 1 | oklahoma colorado Utah | 2 | arkansas colorado oklahoma | 3 | florida michigan florida | --------------------------------- This would allow us to perform the following query to search for '%klah%' select * from Shadow_Table where searchtext like '%klah%' I really don't like having to remember that this shadow table exists and that I'm supposed to use it when I am performing multi-column substring matching, but it probably yields pretty quick reads at the expense of write and storage space. My gut feeling tells me there there is an existing solution built into SQL Server 2008. However, I don't seem to be able to find anything other than research papers on the subject. Any help would be appreciated.

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  • Multi-reader IPC solution?

    - by gct
    I'm working on a framework in C++ (just for fun for now), that lets the user write plugins that use a standard API to stream data between each other. There's going to be three basic transport mechanisms for the data: files, sockets, and some kind of IPC piping system. The system is set up so that for the non-file transport, each stream can have multiple readers. IE once a server socket it setup, multiple computers can connect and stream the data. I'm a little stuck at the multi-reader IPC system though. All my plugins run in threads so they live in the same address space, so some kind of shared memory system would work fine, I was thinking I'd write my own circular buffer with a write pointer and read pointers chassing it around the buffer, but I have my doubts that I can achieve the same performance as something like linux pipes. I'm curious what people would suggest for a multi-reader solution to something like this? Is the overhead for pipes or domain sockets low enough that I could just open a connection to each reader and issue separate writes to each reader? This is intended to be significant volumes of data (tens of mega-samples/sec), so performance is a must.

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  • Noise with multi-threaded raytracer

    - by herber88
    This is my first multi-threaded implementation, so it's probably a beginners mistake. The threads handle the rendering of every second row of pixels (so all rendering is handled within each thread). The problem persists if the threads render the upper and lower parts of the screen respectively. Both threads read from the same variables, can this cause any problems? From what I've understood only writing can cause concurrency problems... Can calling the same functions cause any concurrency problems? And again, from what I've understood this shouldn't be a problem... The only time both threads write to the same variable is when saving the calculated pixel color. This is stored in an array, but they never write to the same indices in that array. Can this cause a problem? Multi-threaded rendered image (Spam prevention stops me from posting images directly..) Ps. I use the exactly same implementation in both cases, the ONLY difference is a single vs. two threads created for the rendering.

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  • How to use different providers for Linq to entities?

    - by Anders Svensson
    I'm trying to familiarize myself a bit more with database programming, and I'm looking at different ways of creating a data access layer for applications. I've tried out a few ways but there is such a jungle of different database technologies that I don't know what to learn. For instance I've tried using datasets with tableadapters. Using that I am able to switch data provider rather easily (by programming against the interfaces such as IDbConnection). This is one thing I would want to achieve. But I also know everyone's talking about LINQ, and I'm trying to get to know that a bit better too. So I have tried using Linq to Sql classes as the data access layer as well, but apparently this is not provider independent (works only for SQL Server). So then I read about the Entity Framework (which just as Linq to SQL apparently has gotten its share of bashing already...). It's supposed to be provider independent everybody says, but how? I tried out a tutorial to create an entity data model, but the only providers to choose from were SQL Server/Express. Just for learning purposes, I would like to know how to use the entity framework with MS Access/OleDb. Also, I would appreciate some input on what is the preferred database technology for data access. Is it LINQ still after all the bashing, or should you just use datasets because they are provider independent? Any pointers for what to learn would be great, because it's just too much to learn it all if I'm not going to use it in the end...!

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  • Issues with the intended behavior of a Service layer?

    - by Rafael Cichocki
    This analysis makes sense, and states anything that avoids code duplication and simplifies maintenance speaks for a service layer. What is the technical behavior? When a service client references a service, does it do so at runtime, or does it happen at compile time? When I change something in the service layer code, will this change be automatically taken into account in all it's clients, or do they need to be individually recompiled? How does this make sense from a testing point of view - I have working code, based on some code from a service, but if that service changes, my code might break?!

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  • Service Layer - how broad should it be, and should it be used also on the local application?

    - by BornToCode
    Background: I need to build a main application with some operations (CRUD and more) (-in winforms), I need to make another application which will re-use some of the functions of the main application (-in webforms). I understood that using service layer is the best approach here. If I understood correctly the service should be calling the function on the BL layer (correct me if I'm wrong) The dilemma: In my main winform UI - should I call the functions from the BL, or from the service? (please explain why) Should I create a service for every single function on the BL even if I need some of the functions only in one UI? for example - should I create services for all the CRUD operations, even though I need to re-use only update operation in the webform? YOUR HELP IS MUCH APPRECIATED

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  • Service Layer - how broad should it be, and should it also be on the local application?

    - by BornToCode
    Background: I need to build a desktop application with some operations (CRUD and more) (=winforms), I need to make another application which will re-use some of the functions of the main application (=webforms). I understood that using service layer is the best approach here. If I understood correctly the service should be calling the function on the BL layer (correct me if I'm wrong) The dilemma: In my main winform UI - should I call the functions from the BL, or from the service? (please explain why) Should I create a service for every single function on the BL even if I need some of the functions only in one UI? for example - should I create services for all the CRUD operations, even though I need to re-use only update operation in the webform? YOUR HELP IS MUCH APPRECIATED

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  • Service Layer - how broad should it be, and should it also be used from the local application?

    - by BornToCode
    The background: I need to build a desktop application with some operations (CRUD and more) (=winforms), I need to make another application which will re-use some of the functions of the main application (=webforms). I'm using service layer for reusing my functions. The service is calling the functions on the BL layer (correct me if I'm doing this wrong). so my desktop has 4 projects - DAL, BL, UI, WEBSERVICES. The dilemma (simple but I still need some more experienced opinions): In my main winform UI - should I call the functions from the BL - bl.getcustomers(), or do it similar to how I call it in the webform, and call the functions from the service - webservices.getcustomers? Should I create a service for every single function on the BL even if I need some of the functions only in one UI? for example - should I create services for all the CRUD operations, even though I need to re-use only update operation in the webform? YOUR HELP IS MUCH APPRECIATED

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  • Include in service layer all the application's functions or only the reusable ones?

    - by BornToCode
    Background: I need to build a main application with some operations (CRUD and more) (-in winforms), I need to make another application which will re-use some of the functions of the main application (-in webforms). I understood that using service layer is the best approach here. If I understood correctly the service should be calling the function on the BL layer (correct me if I'm wrong) The dilemma: In my main winform UI - should I call the functions from the BL, or from the service? (please explain why) Should I create a service for every single function on the BL even if I need some of the functions only in one UI? for example - should I create services for all the CRUD operations, even though I need to re-use only update operation in the webform? YOUR HELP IS MUCH APPRECIATED

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