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  • fancybox - passing 'this' to onClosed function

    - by Phil Jackson
    Hi this is probly really simple but I juast cant seem to figure it out! if( is_logged_out( html ) ) { var throughClick = $(this); $.fancybox( html, { 'autoDimensions' : false, 'width' : 'auto', 'height' : 'auto', 'transitionIn' : 'none', 'transitionOut' : 'none', 'hideOnOverlayClick' : false, 'showCloseButton' : false, 'onClosed' : function( throughClick ) { alert(throughClick.attr('name')); throughClick.trigger('click'); } }); }else{ All i want to do is pass the object of whichever button or link that was clicked, so once the user has logged back in it will process again. Any help is much appreciated.

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  • passing different structs to a function in c

    - by clear2k
    I have different structures that need to be filled out the same way. The only difference is that they are filled based on different data. I was wondering if it's possible to pass different structures to a certain function. What I have in mind is something like: struct stu1 { char *a; int b; }; struct stu2 { char *a; int b; }; static struct not_sure **some_func(struct not_sure *not_sure_here, original_content_list) { // do something and return passed struct for(i=0; i<size_of_original_content_list; i++){ //fill out passed structure } return the_struct; } int main(int argc, char *argv[]) { return_struct1 = some_func(stu1); return_struct2 = some_func(stu2); // do something separate with each return struct... } Any comments will be appreciate it.

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  • sql charateristic function for avg dates

    - by holden
    I have a query which I use to grab specific dates and a price for the date, but now I'd like to use something similar to grab the avg prices for particular days of the week. Here's my current query which works for specific dates to pull from a table called availables: SELECT rooms.name, rooms.roomtype, rooms.id, max(availables.updated_at), MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 0, (availables.price*0.66795805223432), '')) AS day1, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 1, (availables.price*0.66795805223432), '')) AS day2, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 2, (availables.price*0.66795805223432), '')) AS day3, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 3, (availables.price*0.66795805223432), '')) AS day4, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 4, (availables.price*0.66795805223432), '')) AS day5, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 5, (availables.price*0.66795805223432), '')) AS day6, MAX(IF(to_days(availables.bookdate) - to_days('2009-12-10') = 6, (availables.price*0.66795805223432), '')) AS day7, MIN(spots) as spots FROM `availables` INNER JOIN rooms ON availables.room_id=rooms.id WHERE rooms.hotel_id = '5064' AND bookdate BETWEEN '2009-12-10' AND DATE_ADD('2009-12-10', INTERVAL 6 DAY) GROUP BY rooms.name ORDER BY rooms.ppl My first stab which doesn't work, probably because the DAYSOFWEEK function is much different from the to_days... SELECT rooms.id, rooms.name, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 0, (availables.price*0.66795805223432), '')) AS day1, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 1, (availables.price*0.66795805223432), '')) AS day2, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 2, (availables.price*0.66795805223432), '')) AS day3, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 3, (availables.price*0.66795805223432), '')) AS day4, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 4, (availables.price*0.66795805223432), '')) AS day5, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 5, (availables.price*0.66795805223432), '')) AS day6, MAX(IF(DAYOFWEEK(availables.bookdate) - DAYOFWEEK('2009-12-10') = 6, (availables.price*0.66795805223432), '')) AS day7,rooms.ppl AS spots FROM `availables` INNER JOIN `rooms` ON `rooms`.id = `availables`.room_id WHERE (rooms.hotel_id = 5064 AND rooms.ppl > 3 AND availables.price > 0 AND availables.spots > 1) GROUP BY rooms.name ORDER BY rooms.ppl Maybe i'm making this crazy hard and someone knows a much simpler way. It takes data that looks like this #Availables id room_id price spots bookdate 1 26 $5 5 2009-10-20 2 26 $6 5 2009-10-21 to: +----+-------+--------------------+---------------------+---------------------+---------------------+------+------+------+------+ | id | spots | name | day1 | day2 | day3 | day4 | day5 | day6 | day7 | +----+-------+--------------------+---------------------+---------------------+---------------------+------+------+------+------+ | 25 | 4 | Blue Room | 14.9889786921381408 | 14.9889786921381408 | 14.9889786921381408 | | | | | | 26 | 6 | Whatever | 13.7398971344599624 | 13.7398971344599624 | 13.7398971344599624 | | | | | | 27 | 8 | Some name | 11.2417340191036056 | 11.2417340191036056 | 11.2417340191036056 | | | | | | 28 | 8 | Another | 9.9926524614254272 | 9.9926524614254272 | 9.9926524614254272 | | | | | | 29 | 10 | Stuff | 7.4944893460690704 | 7.4944893460690704 | 7.4944893460690704 | | | | | +----+-------+--------------------+---------------------+---------------------+---------------------+------+------+------+---

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  • C++ Newbie: Passing an fstream to a function to read data

    - by vgm64
    I have a text file named num.txt who's only contents is the line 123. Then I have the following: void alt_reader(ifstream &file, char* line){ file.read(line, 3); cout << "First Time: " << line << endl; } int main() { ifstream inFile; int num; inFile.open("num.txt"); alt_reader(inFile, (char*)&num); cout << "Second Time: " << num << endl; } The output is: First Time: 123 Second Time: 3355185 Can you help me figure out how to get an fstream that is read in a function still assign the variable in main? I'm doing this because alt_reader really has a lot more to it, but this is the part I'm stuck on. Thanks a lot for the help.

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  • A function where small changes in input always result in large changes in output

    - by snowlord
    I would like an algorithm for a function that takes n integers and returns one integer. For small changes in the input, the resulting integer should vary greatly. Even though I've taken a number of courses in math, I have not used that knowledge very much and now I need some help... An important property of this function should be that if it is used with coordinate pairs as input and the result is plotted (as a grayscale value for example) on an image, any repeating patterns should only be visible if the image is very big. I have experimented with various algorithms for pseudo-random numbers with little success and finally it struck me that md5 almost meets my criteria, except that it is not for numbers (at least not from what I know). That resulted in something like this Python prototype (for n = 2, it could easily be changed to take a list of integers of course): import hashlib def uniqnum(x, y): return int(hashlib.md5(str(x) + ',' + str(y)).hexdigest()[-6:], 16) But obviously it feels wrong to go over strings when both input and output are integers. What would be a good replacement for this implementation (in pseudo-code, python, or whatever language)?

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  • php OOP function declarations

    - by kris
    I'm a big fan of OOP in php, but i feel like defining class methods gets disorganized so fast. I have a pretty good background in OOP in C++, and i am pretty comfortable with how it is handled there, and am curious if there are ways to do it similarly in php. To be more specific, here is what i mean. I like how in C++ you can define a class header (myclass.h) and then define the actual details of the functions in the implementation file (myclass.cc). Ive found that this can easily be replicated using interfaces in php, but i havent found a good solution for the following: I like to organize my code in C++ in different files based on how they are accessed, so for example, public methods that can be called outside of the class would be in 1 place, and private methods would be organized somewhere else - this is personal preference. Ive tried to define class methods in php like: private function MyPHPClass::myFunction(){ } when the definition isnt directly inside the class block( { } ), but i havent had any success doing this. Ive been through all of the pages on php.net, but couldnt find anything like this. Im assuming that there is no support for something like this, but thought i would ask anyway. thanks

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  • Javascript Function for related select elements onSubmit

    - by Livingston
    I am trying to create (4) Select elements within a form element. Each select element has a different number of options. So if a user click one option on Select #1 and then click another option on Select #2, after hitting submit they will be taken to www.blah.com/option1/option2 page which will display the filtered results. Or they can chose an option from all 4 select menus and be taken to option1/option2/option3/option4 page. The categories are all related .Select #1 is a category, Select #2 is a subcategory of 1, Select #3 is a subcategory of #2 and Select #4 is a subcategory of #3. A great example would be on (LINK) http://www.safavieh.com/rugs (LINK) except only four Select elements. I would also like to add the "Reset" button next to "Submit." I know I need to construct a function in my header and use onSubmit attribute within the form but other than that I am unsure of what's involved so I'm hoping someone could point me in the right direction. It's important I learn most of this for myself. Thanks for your time Livingston

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  • Haskell function composition (.) and function application ($) idioms: correct use.

    - by Robert Massaioli
    I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators. When you write a function that is a composition of other functions you write it like: f = g . h But when you apply something to the end of those functions I write it like this: k = a $ b $ c $ value But the book would write it like this: k = a . b . c $ value Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.

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  • Dynamic function arguments in C++, possible?

    - by Jeshwanth Kumar N K
    I am little new to C++, I have one doubt in variable argument passing. As I mentioned in a sample code below ( This code won't work at all, just for others understanding of my question I framed it like this), I have two functions func with 1 parameter and 2 parameters(parameter overloading). I am calling the func from main, before that I am checking whether I needs to call 2 parameter or 1 parameter. Here is the problem, as I know I can call two fuctions in respective if elseif statements, but I am curious to know whether I can manage with only one function. (In below code I am passing string not int, as I mentioned before this is just for others understanding purpose. #include<iostream.h> #include <string> void func(int, int); void func(int); void main() { int a, b,in; cout << "Enter the 2 for 2 arg, 1 for 1 arg\n"; cin << in; if ( in == 2) { string pass = "a,b"; } elseif ( in == 1) { string pass = "a"; } else { return 0; } func(pass); cout<<"In main\n"<<endl; } void func(int iNum1) { cout<<"In func1 "<<iNum1<<endl; } void func(int iNum1, int iNum2) { cout<<"In func2 "<<iNum1<<" "<<iNum2<<endl; }

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  • function takes only half of the inputs

    - by gcc
    /*-> struct sam set_of_data[4] -<*/ int main (void) {int k=0; for(i=0;i<4;++i) { {char nm; double thelow,theupp; double numbers[200]; scanf("%c %lf %lf",&nm ,&thelow ,&theupp); for(k=0;scanf("%lf",&numbers[k])!=0;++k) ; set_of_data[i]=construct_struct(nm,thelow,theupp,numbers,k); } ; } .. /* helper function to construct data structure*/ sam_t construct_struct(char name,double thelow,double theupp,double *numbers,int k) { stored_name_t stn; stn.name=name; stn.the_lower_limit=thelow; stn.the_upper_limit=theupp; for(i=0 ; i<k && numbers[k]!='\n' && numbers[k]!='\0' ; ++i) stn.numbers[k]=numbers[k]; return stn; } these two funtion takes only half of the inputs(lines starting with D and B didnot be taken,why? inputs: C 3.25 18. 0.01 .01 .02 .04 .08 .02 .02 .05 .065 .08 .1 .13 .2 .05 .04 .04 .03 .01 .005 .0 A 0 7.5 .054 .031 .016 .008 .116 .124 .147 .155 .039 .023 .016 .008 .124 .062 .031 .016 .008 .008 .008 .006 D -1.5 0.5 .012 .025 .05 .1 .1 .1 .025 .012 0 0 0 .012 .025 .1 .2 .1 .05 .039 .025 .025 B 1 3 .117 .058 .029 .015 .007 .007 .007 .015 .022 .029 .036 .044 .051 .058 .066 .073 .080 .088 .095 .103

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  • How to keep the function key locked on Lenovo E431?

    - by Bob
    For the Lenovo e431, how do you keep the function key locked. Right now, the default is when you press F1-F12, he multimedia controls are active. To get to the standard F1-F12, you have to hold down Fn+the function key. This used to available in bios, but for this laptop model, it no longer is available. You can press Fn+esc, and it locks it for that session, but when the computer reboots, this is reset back to the default. Is there a way so that the default is not the multimedia function keys, but just the standard, legacy function keys? Thanks.

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  • Function Point Analysis -- a seriously over-estimating technique?

    - by kizzx2
    I know questions about FPA has been asked numerous times before, but this time I'm taking a more analytical angle at it, backed up with data. 1. First, some data This question is based on a tutorial. He had a "Sample Count" section where he demonstrated it step by step. You can see some screenshots of his sample application here. In the end, he calculated the unadjusted FP to be 99. There is another article on InformIT with industry data on typical hour/FP. It ranges from 2 hours/FP to 27.4 hours/FP. Let's try to stick with 2 for the moment (since SO readers are probably the more efficient crowd :p). 2. Reality check!? Now just check out the screenshots again. Do a little math here 99 * 2 = 198 hours 198 hours / 40 hours per week = 5 weeks Seriously? That sample application is going to take 5 weeks to implement? Is it just my feeling that it wouldn't take any decent programmer longer than one week to have it completed? Now let's try estimating the cost of the project. We'll use New York's minimum wage at the moment (Wikipedia), which is $7.25 198 * 7.25 = $1435.5 From what I could see from the screenshots, this application is a small excel-improvement app. I could have bought MS Office Pro for 200 bucks which gives me greater interoperability (.xls files) and flexibility (spreadsheets). (For the record, that same Web site has another article discussing productivity. It seems like they typically use 4.2 hours/FP, which gives us even more shocking stats: 99 * 4.2 = 415 hours = 10 weeks = almost 3 whopping months! 415 hours * $7.25 = $3000 zomg (That's even assuming that all our poor coders get the minimum wage!) 3. Am I missing something here? Right now, I could come up with several possible explanation: FPA is really only suited for bigger projects (1000+ FPs) so it becomes extremely inaccurate at smaller scale. The hours/FP metric fluctuates abruptly from team to team, project to project. For a small project like this, we could have used something like 0.5 hour/FP or something. (Now this kind of makes the whole estimation thing pointless, unless my firm does the same type of projects for several years with the same team, not really common.) From my experience with several software metrics, Function Point is really not a lightweight metric. If the hour/FP thing fluctuates so much, then what's the point, maybe I could have gone with User Story Points which is a lot faster to get and arguably almost as uncertain. What would be the FP experts' answers to this?

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  • Function Point Analysis -- a seriously overestimating technique?

    - by kizzx2
    I know questions about FPA has been asked numerous times before, but this time I'm taking a more analytical angle at it, backed up with data. 1. First, some data This question is based on a tutorial. He had a "Sample Count" section where he demonstrated it step by step. You can see some screenshots of his sample application here. In the end, he calculated the unadjusted FP to be 99. There is another article on InformIT with industry data on typical hour/FP. It ranges from 2 hours/FP to 27.4 hours/FP. Let's try to stick with 2 for the moment (since SO readers are probably the more efficient crowd :p). 2. Reality check!? Now just check out the screenshots again. Do a little math here 99 * 2 = 198 hours 198 hours / 40 hours per week = 5 weeks Seriously? That sample application is going to take 5 weeks to implement? Is it just my feeling that it wouldn't take any decent programmer longer than one week (I"m not even saying weekend) to have it completed? Now let's try estimating the cost of the project. We'll use New York's minimum wage at the moment (Wikipedia), which is $7.25 198 * 7.25 = $1435.5 From what I could see from the screenshots, this application is a small excel-improvement app. I could have bought MS Office Pro for 200 bucks which gives me greater interoperability (.xls files) and flexibility (spreadsheets). (For the record, that same Web site has another article discussing productivity. It seems like they typically use 4.2 hours/FP, which gives us even more shocking stats: 99 * 4.2 = 415 hours = 10 weeks = almost 3 whopping months! 415 hours * $7.25 = $3000 zomg (That's even assuming that all our poor coders get the minimum wage!) 3. Am I missing something here? Right now, I could come up with several possible explanation: FPA is really only suited for bigger projects (1000+ FPs) so it becomes extremely inaccurate at smaller scale. The hours/FP metric fluctuates abruptly from team to team, project to project. For a small project like this, we could have used something like 0.5 hour/FP or something. (Now this kind of makes the whole estimation thing pointless, unless my firm does the same type of projects for several years with the same team, not really common.) From my experience with several software metrics, Function Point is really not a lightweight metric. If the hour/FP thing fluctuates so much, then what's the point, maybe I could have gone with User Story Points which is a lot faster to get and arguably almost as uncertain. What would be the FP experts' answers to this?

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  • Passing pointer into function, data appears initialized in function, on return appears uninitialize

    - by Luke Mcneice
    Im passing function GetCurrentDate() the pointer to a tm struct. Within that function I printf the uninitialized data, then the initialized. Expected results. However when i return the tm struct appears uninitialized. See console output bellow. What am i doing wrong? uninitialized date:??? ???-1073908332 01:9448278:-1073908376 -1217355836 initialized date:Wed May 5 23:08:40 2010 Caller date:??? ???-1073908332 01:9448278:-1073908376 -121735583 int main() { test(); } int test() { struct tm* CurrentDate; GetCurrentDate(CurrentDate); printf("Caller date:%s\n",asctime (CurrentDate)); return 1; } int GetCurrentDate(struct tm* p_ReturnDate) { printf("uninitialized date:%s\n",asctime (p_ReturnDate)); time_t m_TimeEntity; m_TimeEntity = time(NULL); //setting current time into a time_t struct p_ReturnDate = localtime(&m_TimeEntity); //converting time_t to tm struct printf("initialized date:%s\n",asctime (p_ReturnDate)); return 1; }

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  • PHP function: find argument's variable name, and function calls line number

    - by Majid
    I want to do something like this for simplifying logging operations. Any idea what I should put in for ?[1]? and ?[2]?? function log_var($var) { $line = ?[1]?; $var_name = ?[2]?; $line--; $filepath = 'log-' . date('Y-m-d'). '.txt'; $message = "$line, $var_name = $var\n"; $fp = fopen($filepath, "a"); fwrite($fp, $message); fclose($fp); @chmod($filepath, 0666); return TRUE; } This how I'd use the function in code (numbers are assumed to be line numbers in actual code): 23 $a = 'hello'; 24 log_var($a); 25 $b = 'bye'; 26 log_var($b); And this is what I want to be written to the log file: 23, a = hello 25, b = bye

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  • Self-Executing Anonymous Function vs Prototype

    - by Robotsushi
    In Javascript there are a few clearly prominent techniques for create and manage classes/namespaces in javascript. I am curious what situations warrant using one technique vs. the other. I want to pick one and stick with it moving forward. I write enterprise code that is maintained and shared across multiple teams, and I want to know what is the best practice when writing maintainable javascript ? I tend to prefer Self-Executing Anonymous Functions however I am curious what the community vote is on these techniques. Prototype : function obj() { } obj.prototype.test = function() { alert('Hello?'); }; var obj2 = new obj(); obj2.test(); Self-Closing Anonymous Function : //Self-Executing Anonymous Function (function( skillet, $, undefined ) { //Private Property var isHot = true; //Public Property skillet.ingredient = "Bacon Strips"; //Public Method skillet.fry = function() { var oliveOil; addItem( "\t\n Butter \n\t" ); addItem( oliveOil ); console.log( "Frying " + skillet.ingredient ); }; //Private Method function addItem( item ) { if ( item !== undefined ) { console.log( "Adding " + $.trim(item) ); } } }( window.skillet = window.skillet || {}, jQuery )); //Public Properties console.log( skillet.ingredient ); //Bacon Strips //Public Methods skillet.fry(); //Adding Butter & Fraying Bacon Strips //Adding a Public Property skillet.quantity = "12"; console.log( skillet.quantity ); //12 //Adding New Functionality to the Skillet (function( skillet, $, undefined ) { //Private Property var amountOfGrease = "1 Cup"; //Public Method skillet.toString = function() { console.log( skillet.quantity + " " + skillet.ingredient + " & " + amountOfGrease + " of Grease" ); console.log( isHot ? "Hot" : "Cold" ); }; }( window.skillet = window.skillet || {}, jQuery )); //end of skillet definition try { //12 Bacon Strips & 1 Cup of Grease skillet.toString(); //Throws Exception } catch( e ) { console.log( e.message ); //isHot is not defined } I feel that I should mention that the Self-Executing Anonymous Function is the pattern used by the jQuery team. Update When I asked this question I didn't truly see the importance of what I was trying to understand. The real issue at hand is whether or not to use new to create instances of your objects or to use patterns which do not require constructors of the use of the new keyword. I added my own answer, because in my opinion we should make use of patterns which don't use the new keyword. For more information please see my answer.

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  • SQL SERVER – Introduction to PERCENT_RANK() – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    SQL Server 2012 introduces new analytical functions PERCENT_RANK(). This function returns relative standing of a value within a query result set or partition. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, RANK() OVER(ORDER BY SalesOrderID) Rnk, PERCENT_RANK() OVER(ORDER BY SalesOrderID) AS PctDist FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO The above query will give us the following result: Now let us understand the resultset. You will notice that I have also included the RANK() function along with this query. The reason to include RANK() function was as this query is infect uses RANK function and find the relative standing of the query. The formula to find PERCENT_RANK() is as following: PERCENT_RANK() = (RANK() – 1) / (Total Rows – 1) If you want to read more about this function read here. Now let us attempt the same example with PARTITION BY clause USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) Rnk, PERCENT_RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) AS PctDist FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO Now you will notice that the same logic is followed in follow result set. I have now quick question to you – how many of you know the logic/formula of PERCENT_RANK() before this blog post? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Activation Function, Initializer function, etc, effects on neural networks for face detection

    - by harry
    There's various activation functions: sigmoid, tanh, etc. And there's also a few initializer functions: Nguyen and Widrow, random, normalized, constant, zero, etc. So do these have much effect on the outcome of a neural network specialising in face detection? Right now I'm using the Tanh activation function and just randomising all the weights from -0.5 to 0.5. I have no idea if this is the best approach though, and with 4 hours to train the network each time, I'd rather ask on here than experiment!

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  • No warning from gcc when function definition in linked source different from function prototype in h

    - by c_c
    Hi, I had a problem with a part of my code, which after some iterations seemed to read NaN as value of a int of a struct. I think I found the error, but am still wondering why gcc (version 3.2.3 on a embedded Linux with busybox) did not warn me. Here are the important parts of the code: A c file and its header for functions to acquire data over USB: // usb_control.h typedef struct{ double mean; short *values; } DATA_POINTS; typedef struct{ int size; DATA_POINTS *channel1; //....7 more channels } DATA_STRUCT; DATA_STRUCT *create_data_struct(int N); // N values per channel int free_data_struct(DATA_STRUCT *data); int aqcu_data(DATA_STRUCT *data, int N); A c and header file with helper function (math, bitshift,etc...): // helper.h int mean(DATA_STRUCT *data); // helper.c (this is where the error is obviously) double mean(DATA_STRUCT *data) { // sum in for loop data->channel1->mean = sum/data->N; // ...7 more channels // a printf here displayed the mean values corretly } The main file // main.c #include "helper.h" #include "usb_control.h" // Allocate space for data struct DATA_STRUCT *data = create_data_struct(N); // get data for different delays for (delay = 0; delay < 500; delay += pw){ acqu_data(data, N); mean(data); // printf of the mean values first is correct. Than after 5 iterations // it is always NaN for channel1. The other channels are displayed correctly; } There were no segfaults nor any other missbehavior, just the NaN for channel1 in the main file. After finding the error, which was not easy, it was of course east to fix. The return type of mean(){} was wrong in the definition. Instead of double mean() it has to be int mean() as the prototype defines. When all the functions are put into one file, gcc warns me that there is a redefinition of the function mean(). But as I compile each c file seperately and link them afterwards gcc seems to miss that. So my questions would be. Why didn't I get any warnings, even non with gcc -Wall? Or is there still another error hidden which is just not causing problems now? Regards, christian

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  • Can a destructor be recursive?

    - by Cubbi
    Is this program well-defined, and if not, why exactly? #include <iostream> #include <new> struct X { int cnt; X (int i) : cnt(i) {} ~X() { std::cout << "destructor called, cnt=" << cnt << std::endl; if ( cnt-- > 0 ) this->X::~X(); // explicit recursive call to dtor } }; int main() { char* buf = new char[sizeof(X)]; X* p = new(buf) X(7); p->X::~X(); // explicit call to dtor delete[] buf; } My reasoning: although invoking a destructor twice is undefined behavior, per 12.4/14, what it says exactly is this: the behavior is undefined if the destructor is invoked for an object whose lifetime has ended Which does not seem to prohibit recursive calls. While the destructor for an object is executing, the object's lifetime has not yet ended, thus it's not UB to invoke the destructor again. On the other hand, 12.4/6 says: After executing the body [...] a destructor for class X calls the destructors for X's direct members, the destructors for X's direct base classes [...] which means that after the return from a recursive invocation of a destructor, all member and base class destructors will have been called, and calling them again when returning to the previous level of recursion would be UB. Therefore, a class with no base and only POD members can have a recursive destructor without UB. Am I right?

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  • How to use R's ellipsis feature when writing your own function?

    - by Ryan Thompson
    The R language has a nifty feature for defining functions that can take a variable number of arguments. For example, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table. Example usage: > data.frame(letters=c("a", "b", "c"), numbers=c(1,2,3), notes=c("do", "re", "mi")) letters numbers notes 1 a 1 do 2 b 2 re 3 c 3 mi The function's signature includes an ellipsis, like this: function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, stringsAsFactors = default.stringsAsFactors()) { [FUNCTION DEFINITION HERE] } I would like to write a function that does something similar, taking multiple values and consolidating them into a single return value (as well as doing some other processing). In order to do this, I need to figure out how to "unpack" the ... from the function's arguments within the function. I don't know how to do this. The relevant line in the function definition of data.frame is object <- as.list(substitute(list(...)))[-1L], which I can't make any sense of. So how can I convert the ellipsis from the function's signature into, for example, a list? To be more specific, how can I write get_list_from_ellipsis in the code below? my_ellipsis_function(...) { input_list <- get.list.from.ellipsis(...) output_list <- lapply(X=input_list, FUN=do_something_interesting) return(output_list) } my_ellipsis_function(a=1:10,b=11:20,c=21:30)

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  • Java iterative vs recursive

    - by user1389813
    Can anyone explain why the following recursive method is faster than the iterative one (Both are doing it string concatenation) ? Isn't the iterative approach suppose to beat up the recursive one ? plus each recursive call adds a new layer on top of the stack which can be very space inefficient. private static void string_concat(StringBuilder sb, int count){ if(count >= 9999) return; string_concat(sb.append(count), count+1); } public static void main(String [] arg){ long s = System.currentTimeMillis(); StringBuilder sb = new StringBuilder(); for(int i = 0; i < 9999; i++){ sb.append(i); } System.out.println(System.currentTimeMillis()-s); s = System.currentTimeMillis(); string_concat(new StringBuilder(),0); System.out.println(System.currentTimeMillis()-s); } I ran the program multiple time, and the recursive one always ends up 3-4 times faster than the iterative one. What could be the main reason there that is causing the iterative one slower ?

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  • How to write PowerShell code part 2 (Using function)

    - by ybbest
    In the last post, I have showed you how to use external configuration file in your PowerShell script. In this post, I will show you how to create PowerShell function and call external PowerShell script.You can download the script here. 1. In the original script, I create the site directly using New-SPSite command. I will refactor it so that I will create a new function to create the site using New-SPSite. The PowerShell function is quite similar to a C# method. You put your function parameters in () and separate each parameter by a comma (,). Then you put your method body in {}. function add ([int] $num1 , [int] $num2){ $total=$num1+$num2 #Return $total $total } 2. The difference is you do not need semi-colon (;) at the end of each statement and when calling the method you do not need comma (,) to separate each parameter. function add ([int] $num1 , [int] $num2){ $total=$num1+$num2 #Return $total $total } #Calling the function [int] $num1=3 [int] $num2=4 $d= add $num1 $num2 Write-Host $d 3. If you like to return anything from the function, you just need to type in the object you like to return, not need to type return .e.g. $ObjectToReturn not return $ObjectToReturn

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