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  • K-means algorithm variation with minimum measure of size

    - by user1464628
    I'm looking for some algorithm such as k-means for grouping points on a map into a fixed number of groups, by distance. The number of groups has already been decided, but the trick part (at least for me) is to meet the criteria that the sum of MOS of each group should in the certain range, say bigger than 1. Is there any way to make that happen? ID MOS X Y 1 0.47 39.27846 -76.77101 2 0.43 39.22704 -76.70272 3 1.48 39.24719 -76.68485 4 0.15 39.25172 -76.69729 5 0.09 39.24341 -76.69884

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  • My first Lisp macro; is it leaky?

    - by Tom Martin
    I've been working through Practical Common Lisp and as an exercise decided to write a macro to determine if a number is a multiple of another number: (defmacro multp (value factor) `(= (rem ,value ,factor) 0)) so that : (multp 40 10) evaluates to true whilst (multp 40 13) does not The question is does this macro leak in some way? Also is this "good" Lisp? Is there already an existing function/macro that I could have used?

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  • Is it possible to write a database view that encompasses one-to-many relationships?

    - by Brandon Linton
    So I'm not necessarily saying this is even a good idea if it were possible, since the schema of the view would be extremely volatile, but is there any way to represent a has-many relationship in a single view? For example, let's say I have a customer that can have any number of addresses in the database. Is there any way to list out each column of each address with perhaps a number as a part of the alias (e.g., columns like Customer Id, Name, Address_Street_1, Address_Street_2, etc)? Thanks!

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  • Need help with basic optimization problem

    - by ??iu
    I know little of optimization problems, so hopefully this will be didactic for me: rotors = [1, 2, 3, 4...] widgets = ['a', 'b', 'c', 'd' ...] assert len(rotors) == len(widgets) part_values = [ (1, 'a', 34), (1, 'b', 26), (1, 'c', 11), (1, 'd', 8), (2, 'a', 5), (2, 'b', 17), .... ] Given a fixed number of widgets and a fixed number of rotors, how can you get a series of widget-rotor pairs that maximizes the total value where each widget and rotor can only be used once?

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  • Foreign Keys and Primary Keys at the same time

    - by Bader
    hello , i am trying to create table (orderdetails) , the table has two FKs and PKs at the same keys here is my code create table OrderDetails2 ( PFOrder_ID Number(3) PFProduct_ID Number(3) CONSTRAINT PF PRIMARY KEY (PFOrder_ID,PFProduct_ID), CONSTRAINT FK_1 FOREIGN KEY (PFProudct_ID) REFERENCES Product(Product_ID), CONSTRAINT FK_2 FOREIGN KEY (PFOrder_ID) REFERENCES Orderr(Order_ID) ); i am using Oracle express , a problem pops when i run the code , here is it ORA-00907: missing right parenthesis what is the problem ?

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  • Mysql change column details

    - by Ankur
    I am trying to redefine the number of varchars a column can have (in a MySQL db). I am doing alter table obj_details IMG_SRC IMG_SRC varchar(180); I want to change the number of characters that can be used in the column IMG_SRC to 180 (it is currently 100). But I get an error saying that I should check the syntax near IMG_SRC IMG_SRC varchar(180).

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  • Rendering of graphics different depending on position

    - by jedierikb
    When drawing parallel vertical lines with a fixed distance between them (1.75 pixels) with a non-integer x-value-offset to both lines, the lines are drawn differently based on the offset. In the picture below are two pairs of very close together vertical lines. As you can see, they look very different. This is frustrating, especially when animating the sprite. Any ideas how ensure that sprites-with-non-integer-positions' graphics will visually display the same? package { import flash.display.Sprite; import flash.display.StageAlign; import flash.display.StageScaleMode; import flash.events.Event; public class tmpa extends Sprite { private var _sp1:Sprite; private var _sp2:Sprite; private var _num:Number; public function tmpa( ):void { stage.align = StageAlign.TOP_LEFT; stage.scaleMode = StageScaleMode.NO_SCALE; _sp1 = new Sprite( ); drawButt( _sp1, 0 ); _sp1.x = 100; _sp1.y = 100; _num = 0; _sp2 = new Sprite( ); drawButt( _sp2, _num ); _sp2.x = 100; _sp2.y = 200; addChild( _sp1 ); addChild( _sp2 ); addEventListener( Event.ENTER_FRAME, efCb, false, 0, true ); } private function efCb( evt:Event ):void { _num += .1; if (_num > 400) { _num = 0; } drawButt( _sp2, _num ); } private function drawButt( sp:Sprite, offset:Number ):void { var px1:Number = 1 + offset; var px2:Number = 2.75 + offset; sp.graphics.clear( ); sp.graphics.lineStyle( 1, 0, 1, true ); sp.graphics.moveTo( px1, 1 ); sp.graphics.lineTo( px1, 100 ); sp.graphics.lineStyle( 1, 0, 1, true ); sp.graphics.moveTo( px2, 1 ); sp.graphics.lineTo( px2, 100 ); } } } edit from original post which thought the problem was tied to the x-position of the sprite.

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  • Python/Django Concatenate a string depending on whether that string exists

    - by Douglas Meehan
    I'm creating a property on a Django model called "address". I want address to consist of the concatenation of a number of fields I have on my model. The problem is that not all instances of this model will have values for all of these fields. So, I want to concatenate only those fields that have values. What is the best/most Pythonic way to do this? Here are the relevant fields from the model: house = models.IntegerField('House Number', null=True, blank=True) suf = models.CharField('House Number Suffix', max_length=1, null=True, blank=True) unit = models.CharField('Address Unit', max_length=7, null=True, blank=True) stex = models.IntegerField('Address Extention', null=True, blank=True) stdir = models.CharField('Street Direction', max_length=254, null=True, blank=True) stnam = models.CharField('Street Name', max_length=30, null=True, blank=True) stdes = models.CharField('Street Designation', max_length=3, null=True, blank=True) stdessuf = models.CharField('Street Designation Suffix',max_length=1, null=True, blank=True) I could just do something like this: def _get_address(self): return "%s %s %s %s %s %s %s %s" % (self.house, self.suf, self.unit, self.stex, self.stdir, self.stname, self.stdes, self.stdessuf) but then there would be extra blank spaces in the result. I could do a series of if statements and concatenate within each, but that seems ugly. What's the best way to handle this situation? Thanks.

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  • Interesting task using random numbers only

    - by psihodelia
    Given any number of the random real numbers from the interval [0,1] is there exist any method to construct a floating point number with zero decimal part? Your algorithm can use only random() function calls and no variables or constants. No constants and variables are allowed, no type casting is allowed. You can use for/while, if/else or any other programming language operands.

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  • handling javaScript alerts when running a selenium test?

    - by Mo
    Hi I am am running some selenium tests(ruby) on my web page and as i enter an invalid characters in to a text box i have the JavaScript throw a alert like so if(isNaN($(this).val()) || Number($(this).val().valueOf() <=0)){ alert("Please Enter A Number"); } how can i handle this alert when its made and close the pop up? i tried to use the wait_for_pop_up() and close() but i think that's only for browser pop up's and not JavaScript alerts. any ideas? thanks

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  • Trying to run multiple HTTP requests in parallel, but being limited by Windows (registry)

    - by Nailuj
    I'm developing an application (winforms C# .NET 4.0) where I access a lookup functionality from a 3rd party through a simple HTTP request. I call an url with a parameter, and in return I get a small string with the result of the lookup. Simple enough. The challenge is however, that I have to do lots of these lookups (a couple of thousands), and I would like to limit the time needed. Therefore I would like to run requests in parallel (say 10-20). I use a ThreadPool to do this, and the short version of my code looks like this: public void startAsyncLookup(Action<LookupResult> returnLookupResult) { this.returnLookupResult = returnLookupResult; foreach (string number in numbersToLookup) { ThreadPool.QueueUserWorkItem(lookupNumber, number); } } public void lookupNumber(Object threadContext) { string numberToLookup = (string)threadContext; string url = @"http://some.url.com/?number=" + numberToLookup; WebClient webClient = new WebClient(); Stream responseData = webClient.OpenRead(url); LookupResult lookupResult = parseLookupResult(responseData); returnLookupResult(lookupResult); } I fill up numbersToLookup (a List<String>) from another place, call startAsyncLookup and provide it with a call-back function returnLookupResult to return each result. This works, but I found that I'm not getting the throughput I want. Initially I thought it might be the 3rd party having a poor system on their end, but I excluded this by trying to run the same code from two different machines at the same time. Each of the two took as long as one did alone, so I could rule out that one. A colleague then tipped me that this might be a limitation in Windows. I googled a bit, and found amongst others this post saying that by default Windows limits the number of simultaneous request to the same web server to 4 for HTTP 1.0 and to 2 for HTTP 1.1 (for HTTP 1.1 this is actually according to the specification (RFC2068)). The same post referred to above also provided a way to increase these limits. By adding two registry values to [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings] (MaxConnectionsPerServer and MaxConnectionsPer1_0Server), I could control this myself. So, I tried this (sat both to 20), restarted my computer, and tried to run my program again. Sadly though, it didn't seem to help any. I also kept an eye on the Resource Monitor (see screen shot) while running my batch lookup, and I noticed that my application (the one with the title blacked out) still only was using two TCP connections. So, the question is, why isn't this working? Is the post I linked to using the wrong registry values? Is this perhaps not possible to "hack" in Windows any longer (I'm on Windows 7)? Any ideas would be highly appreciated :) And just in case anyone should wonder, I have also tried with different settings for MaxThreads on ThreadPool (everyting from 10 to 100), and this didn't seem to affect my throughput at all, so the problem shouldn't be there either.

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  • Objective C: Compare timeInMillis with current time

    - by Srivathsan Canchi
    Hello, In my iPhone application, I need to calculate the time difference between the time a message was created on the server, and the time my phone received it. The server (Java) puts in a number returned by System.currentTimeMillis() as metadata along with the message. How do I compare this number with the current time on the device? Could not find a suitable NSDate method to do this comparison. Thanks in advance!

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  • Make a String text Bold in Java Android

    - by meskh
    I want to make Habit Number: bold , I tried the HTML tag but it didn't work. I did some research but couldn't find any. Hope someone is able to help me. Thanks! String habitnumber = "Habit Number: " + String.valueOf(habitcounter); String Title = habit.getTitle(); String description = habit.getDescription(); //Set text for the row tv.setText(habitnumber+ "\n" + Title + " \n" + description + "\n --------------------");

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  • PHP: Manage roles with math?

    - by Mike
    I once saw an article about how to use a specific type of numbering system to manage roles. A user would be assigned a specific role number and depending on a calculation, the number could stand for multiple roles. Can anybody share this technique with me or share a link? Thanks!

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  • complex arguments for function

    - by myPost1
    My task is to create function funCall taking four arguments : pointer for 2d array of ints that stores pairs of numbers variable int maintaining number of numbers in 2d array pointer for table of pointers to functions int variable storing info about number of pointers to functions I was thinking about something like this : typedef int(*funPtr)(int, int); funPtr arrayOfFuncPtrs[]; void funCall( *int[][]k, int a, *funPtr z, int b); { }

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  • Best solution for a windows service with constant running threads in C# 4.0

    - by dagda1
    Hi, I want to create a windows service that will create x number of threads that wake up every x number of minutes and do some work. I think the task scheduling or parallel framework is a bad fit for this type of work as it is best suited for work that starts, completes and finishes rather than is constant. Should I look at utilising a thread pool for this approach or does anyone have any advice for a good solution? Thanks Paul

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  • Repeat Customers Each Year (Retention)

    - by spazzie
    I've been working on this and I don't think I'm doing it right. |D Our database doesn't keep track of how many customers we retain so we looked for an alternate method. It's outlined in this article. It suggests you have this table to fill in: Year Number of Customers Number of customers Retained in 2009 Percent (%) Retained in 2009 Number of customers Retained in 2010 Percent (%) Retained in 2010 .... 2008 2009 2010 2011 2012 Total The table would go out to 2012 in the headers. I'm just saving space. It tells you to find the total number of customers you had in your starting year. To do this, I used this query since our starting year is 2008: select YEAR(OrderDate) as 'Year', COUNT(distinct(billemail)) as Customers from dbo.tblOrder where OrderDate >= '2008-01-01' and OrderDate <= '2008-12-31' group by YEAR(OrderDate) At the moment we just differentiate our customers by email address. Then you have to search for the same names of customers who purchased again in later years (ours are 2009, 10, 11, and 12). I came up with this. It should find people who purchased in both 2008 and 2009. SELECT YEAR(OrderDate) as 'Year',COUNT(distinct(billemail)) as Customers FROM dbo.tblOrder o with (nolock) WHERE o.BillEmail IN (SELECT DISTINCT o1.BillEmail FROM dbo.tblOrder o1 with (nolock) WHERE o1.OrderDate BETWEEN '2008-1-1' AND '2009-1-1') AND o.BillEmail IN (SELECT DISTINCT o2.BillEmail FROM dbo.tblOrder o2 with (nolock) WHERE o2.OrderDate BETWEEN '2009-1-1' AND '2010-1-1') --AND o.OrderDate BETWEEN '2008-1-1' AND '2013-1-1' AND o.BillEmail NOT LIKE '%@halloweencostumes.com' AND o.BillEmail NOT LIKE '' GROUP BY YEAR(OrderDate) So I'm just finding the customers who purchased in both those years. And then I'm doing an independent query to find those who purchased in 2008 and 2010, then 08 and 11, and then 08 and 12. This one finds 2008 and 2010 purchasers: SELECT YEAR(OrderDate) as 'Year',COUNT(distinct(billemail)) as Customers FROM dbo.tblOrder o with (nolock) WHERE o.BillEmail IN (SELECT DISTINCT o1.BillEmail FROM dbo.tblOrder o1 with (nolock) WHERE o1.OrderDate BETWEEN '2008-1-1' AND '2009-1-1') AND o.BillEmail IN (SELECT DISTINCT o2.BillEmail FROM dbo.tblOrder o2 with (nolock) WHERE o2.OrderDate BETWEEN '2010-1-1' AND '2011-1-1') --AND o.OrderDate BETWEEN '2008-1-1' AND '2013-1-1' AND o.BillEmail NOT LIKE '%@halloweencostumes.com' AND o.BillEmail NOT LIKE '' GROUP BY YEAR(OrderDate) So you see I have a different query for each year comparison. They're all unrelated. So in the end I'm just finding people who bought in 2008 and 2009, and then a potentially different group that bought in 2008 and 2010, and so on. For this to be accurate, do I have to use the same grouping of 2008 buyers each time? So they bought in 2009 and 2010 and 2011, and 2012? This is where I'm worried and not sure how to proceed or even find such data. Any advice would be appreciated! Thanks!

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  • problem in printing floating point

    - by kudi
    hi I am using IAR c compiler, I am trying to print floating point value like printf("version number: %f\n",1.4); but I am always getting like below in console version number:ERROR help please thanks in advance kudi

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  • Maximal Length of List to Shuffle with Python random.shuffle?

    - by Henrik
    I have a list which I shuffle with the Python built in shuffle function (random.shuffle) However, the Python reference states: Note that for even rather small len(x), the total number of permutations of x is larger than the period of most random number generators; this implies that most permutations of a long sequence can never be generated. Now, I wonder what this "rather small len(x)" means. 100, 1000, 10000,... Can anybody clarify? Thanks!

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  • A quick way to map unordered list of longs to buffer location ?

    - by alhazen
    I have a large number of points (indexed by long) that are processed by multiple threads and I'm using a buffer to hold the output results in order. As the number of points processed is huge, what would be an efficient way to map the indexes of the points to the corresponding ordered position in the buffer ? Example: long bufferIndex bufferIndex index (if BufferSize = 2) (if BufferSize = 4) ---------------------------------------------- 2938 0 0 2939 1 1 2941 1 3 2940 0 2 Thanks.

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  • How to draw N first elements?

    - by noober
    Hello all, There is a canvas element with 10 children (polygons). There is a number in my code from 1 to 10. I'd like to draw the first N elements from the children elements, base on my number. It would be the best solution to do this from XAML with a minimum code-behind like this: ... MyCanvas.N = 5; ...

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