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• GROUP BY a date, with ordering by date.

  - by standard

  Take this simple query: SELECT DATE_FORMAT(someDate, '%y-%m-%d') as formattedDay FROM someTable GROUP BY formatterDay This will select rows from a table with only 1 row per date. How do I ensure that the row selected per date is the earliest for that date, without doing an ordered subquery in the FROM? Cheers

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• problem to Get Date, month Year separately From database in Php File ?

  - by aamir Fayyaz

  i want to separate date, month, time, hour, min ,sec getting from database, for count down timer, in data base stored date is 2010/10/10: me using this code : $m=date('m',$row['Date']); $d=date('d',$row['Date']); output is month=31 date = 12....

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• mysql - combining columns and tables

  - by Phil Jackson

  Hi, I'm not much of a SQL man so I'm seeking help for this one. I have a site where I have a database for all accounts and whatnot, and another for storing actions that the user has done on the site. Each user has their own table but I want to combine the data of each user group ( all users that are "linked together" ) and order that data in the time the actions took place. Heres what I have; <?php $query = "SELECT `TALKING_TO` FROM `nnn_instant_messaging` WHERE `AUTHOR` = '" . DISPLAY_NAME . "' AND `TALKING_TO` != ''"; $query = mysql_query( $query, $CON ) or die( "_error_ " . mysql_error()); if( mysql_num_rows( $query ) != 0 ) { $table_str = ""; $select_ref_clause = "( "; $select_time_stamp_clause = "( "; while( $row = mysql_fetch_array( $query ) ) { $table_str .= "`actvbiz_networks`.`" . $row['TALKING_TO'] . "`, "; $select_ref_clause .= "`actvbiz_networks`.`" . $row['TALKING_TO'] . ".REF`, "; $select_time_stamp_clause .= "`actvbiz_networks`.`" . $row['TALKING_TO'] . ".TIME_STAMP`, "; } $table_str = $table_str . "`actvbiz_networks`.`" . DISPLAY_NAME . "`"; $select_ref_clause = substr($select_ref_clause, 0, -2) . ") AS `REF`, "; $select_time_stamp_clause = substr($select_time_stamp_clause, 0, -2) . " ) AS `TIME_STAMP`"; }else{ $table_str = "`actvbiz_networks`.`" . DISPLAY_NAME . "`"; $select_ref_clause = "`REF`, "; $select_time_stamp_clause = "`TIME_STAMP`"; } $where_clause = $select_ref_clause . $select_time_stamp_clause; $query = "SELECT " . $where_clause . " FROM " . $table_str . " ORDER BY TIME_STAMP"; die($query); $query = mysql_query( $query, $CON ) or die( "_error_ " . mysql_error()); if( mysql_num_rows( $query ) != 0 ) { }else{ ?> <p>Currently no actions have taken place in your network.</p> <?php } ?> The code above returns the sql statement: SELECT ( `actvbiz_networks`.`john_doe.REF`, `actvbiz_networks`.`Emmalene_Jackson.REF`) AS `REF`, ( `actvbiz_networks`.`john_doe.TIME_STAMP`, `actvbiz_networks`.`Emmalene_Jackson.TIME_STAMP` ) AS `TIME_STAMP` FROM `actvbiz_networks`.`john_doe`, `actvbiz_networks`.`Emmalene_Jackson`, `actvbiz_networks`.`act_web_designs` ORDER BY TIME_STAMP I really am learning on my feet with SQL. Its not the PHP I have a problem with ( I can quite happly code away with PHP ) I'ts just help with the SQL statement. Any help much appreciated, REgards, Phil

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• Problems with Threading in Python 2.5, KeyError: 51, Help debugging?

  - by vignesh-k

  I have a python script which runs a particular script large number of times (for monte carlo purpose) and the way I have scripted it is that, I queue up the script the desired number of times it should be run then I spawn threads and each thread runs the script once and again when its done. Once the script in a particular thread is finished, the output is written to a file by accessing a lock (so my guess was that only one thread accesses the lock at a given time). Once the lock is released by one thread, the next thread accesses it and adds its output to the previously written file and rewrites it. I am not facing a problem when the number of iterations is small like 10 or 20 but when its large like 50 or 150, python returns a KeyError: 51 telling me element doesn't exist and the error it points out to is within the lock which puzzles me since only one thread should access the lock at once and I do not expect an error. This is the class I use: class errorclass(threading.Thread): def __init__(self, queue): self.__queue=queue threading.Thread.__init__(self) def run(self): while 1: item = self.__queue.get() if item is None: break result = myfunction() lock = threading.RLock() lock.acquire() ADD entries from current thread to entries in file and REWRITE FILE lock.release() queue = Queue.Queue() for i in range(threads): errorclass(queue).start() for i in range(desired iterations): queue.put(i) for i in range(threads): queue.put(None) Python returns with KeyError: 51 for large number of desired iterations during the adding/write file operation after lock access, I am wondering if this is the correct way to use the lock since every thread has a lock operation rather than every thread accessing a shared lock? What would be the way to rectify this?

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• How can I get DocId when adding a document in Lucene index?

  - by Rohit

  I am indexing a row of data from database in Lucene.Net. A row is equivalent of Document. I want to update my database with the DocId, so that I can use the DocId in the results to be able to retrieve rows quickly. I currently first retrive the PK from the result docs which I think should be slower than retriving directly from the database using DocId. How can I find the DocId when adding a document to Lucene?

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• How to solve linker error in matrix multiplication in c using lapack library?

  - by Malar

  I did Matrix multiplication using lapack library, I am getting an error like below. Can any one help me? "error LNK2019: unresolved external symbol "void __cdecl dgemm(char,char,int *,int *,int *,double *,double *,int *,double *,int *,double *,double *,int *)" (?dgemm@@YAXDDPAH00PAN1010110@Z) referenced in function _main" 1..\bin\matrixMultiplicationUsingLapack.exe : fatal error LNK1120: 1 unresolved externals I post my code below # define matARowSize 2 // -- Matrix 1 number of rows # define matAColSize 2 // -- Matrix 1 number of cols # define matBRowSize 2 // -- Matrix 2 number of rows # define matBColSize 2 // -- Matrix 2 number of cols using namespace std; void dgemm(char, char, int *, int *, int *, double *, double *, int *, double *, int *, double *, double *, int *); int main() { double iMatrixA[matARowSize*matAColSize]; // -- Input matrix 1 {m x n} double iMatrixB[matBRowSize*matBColSize]; // -- Input matrix 2 {n x k} double iMatrixC[matARowSize*matBColSize]; // -- Output matrix {m x n * n x k = m x k} double alpha = 1.0f; double beta = 0.0f; int n = 2; iMatrixA[0] = 1; iMatrixA[1] = 1; iMatrixA[2] = 1; iMatrixA[3] = 1; iMatrixB[0] = 1; iMatrixB[1] = 1; iMatrixB[2] = 1; iMatrixB[3] = 1; //dgemm('N','N',&n,&n,&n,&alpha,iMatrixA,&n,iMatrixB,&n,&beta,iMatrixC,&n); dgemm('N','N',&n,&n,&n,&alpha,iMatrixA,&n,iMatrixB,&n,&beta,iMatrixC,&n); std::cin.get(); return 0; }

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• How to write a simple Lexer/Parser with antlr 2.7?

  - by Burkhard

  Hello, I have a complex grammar (in antlr 2.7) which I need to extend. Having never used antlr before, I wanted to write a very simple Lexer and Parser first. I found a very good explanation for antlr3 and tried to adapt it: header{ #include <iostream> using namespace std; } options { language="Cpp"; } class P2 extends Parser; /* This will be the entry point of our parser. */ eval : additionExp ; /* Addition and subtraction have the lowest precedence. */ additionExp : multiplyExp ( "+" multiplyExp | "-" multiplyExp )* ; /* Multiplication and addition have a higher precedence. */ multiplyExp : atomExp ( "*" atomExp | "/" atomExp )* ; /* An expression atom is the smallest part of an expression: a number. Or when we encounter parenthesis, we're making a recursive call back to the rule 'additionExp'. As you can see, an 'atomExp' has the highest precedence. */ atomExp : Number | "(" additionExp ")" ; /* A number: can be an integer value, or a decimal value */ number : ("0".."9")+ ("." ("0".."9")+)? ; /* We're going to ignore all white space characters */ protected ws : (" " | "\t" | "\r" | "\n") { newline(); } ; It does generate four files without errors: P2.cpp, P2.hpp, P2TokenTypes.hpp and P2TokenTypes.txt. But now what? How do I create a working programm with that? I tried to add these files to a VS2005-WinConsole-Project but it does not compile: p2.cpp(277) : fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source?

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• How to duplicate all data in a table except for a single column that should be changed.

  - by twiga

  I have a question regarding a unified insert query against tables with different data structures (Oracle). Let me elaborate with an example: tb_customers ( id NUMBER(3), name VARCHAR2(40), archive_id NUMBER(3) ) tb_suppliers ( id NUMBER(3), name VARCHAR2(40), contact VARCHAR2(40), xxx, xxx, archive_id NUMBER(3) ) The only column that is present in all tables is [archive_id]. The plan is to create a new archive of the dataset by copying (duplicating) all records to a different database partition and incrementing the archive_id for those records accordingly. [archive_id] is always part of the primary key. My problem is with select statements to do the actual duplication of the data. Because the columns are variable, I am struggling to come up with a unified select statement that will copy the data and update the archive_id. One solution (that works), is to iterate over all the tables in a stored procedure and do a: CREATE TABLE temp as (SELECT * from ORIGINAL_TABLE); UPDATE temp SET archive_id=something; INSERT INTO temp (select * from temp); DROP TABLE temp; I do not like this solution very much as the DDL commands muck up all restore points. Does anyone else have any solution?

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• random quote generator with php, ajax and mysql

  - by fusion

  i've tried using this code and this to make a random quote generator, but it doesn't display anything. my questions are: what is wrong with my code? in the above tut, the quote is generated on a button click, i'd like a random quote to be displayed every 30 mins automatically. how do i do this? //////////////////////// quote.html: <!DOCTYPE html> <script src="ajax.js" type="text/javascript"></script> <body> <!–create the div for the quotes land–> <div id="quote"><strong>this</strong></div> <div><a style="cursor:pointer" onclick="run_query();">Next quote …</a></div> </body> </html> ///////////////////// quote.php: <?php include 'config.php'; // 'text' is the name of your table that contains // the information you want to pull from $rowcount = mysql_query("select count(*) as rows from quotes"); // Gets the total number of items pulled from database. while ($row = mysql_fetch_assoc($rowcount)) { $max = $row["rows"]; } // Selects an item's index at random $rand = rand(1,$max)-1; $result = mysql_query("select * from quotes limit $rand, 1"); $row = mysql_fetch_array($result); $randomOutput = $row['storedText']; echo '<p>' . $randomOutput . '</p>'; //////////// ajax.js: var xmlHttp function run_query() { xmlHttp=GetXmlHttpObject(); if (xmlHttp==null) { alert ("This browser does not support HTTP Request"); return; } // end if var url="quote.php"; xmlHttp.onreadystatechange=stateChanged; xmlHttp.open("GET",url,true); xmlHttp.send(null); } //end function function stateChanged(){ if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){ document.getElementById("quote").innerHTML=xmlHttp.responseText; } //end if } //end function function GetXmlHttpObject() { var xmlHttp=null; try { // For these browsers: Firefox, Opera 8.0+, Safari xmlHttp=new XMLHttpRequest(); }catch (e){ //For Internet Explorer try{ xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); } } return xmlHttp; } //end function

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• How to extract data from F# list

  - by David White

  Following up my previous question, I'm slowly getting the hang of FParsec (though I do find it particularly hard to grok). My next newbie F# question is, how do I extract data from the list the parser creates? For example, I loaded the sample code from the previous question into a module called Parser.fs, and added a very simple unit test in a separate module (with the appropriate references). I'm using XUnit: open Xunit [<Fact>] let Parse_1_ShouldReturnListContaining1 () = let interim = Parser.parse("1") Assert.False(List.isEmpty(interim)) let head = interim.Head // I realise that I have only one item in the list this time Assert.Equal("1", ???) Interactively, when I execute parse "1" the response is: val it : Element list = [Number "1"] and by tweaking the list of valid operators, I can run parse "1+1" to get: val it : Element list = [Number "1"; Operator "+"; Number "1"] What do I need to put in place of my ??? in the snippet above? And how do I check that it is a Number, rather than an Operator, etc.?

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• Extending / changing how Zend_Search_Lucene searches

  - by Grant Collins

  Hi, I am currently using Zend_Search_Lucene to index and search a number of documents currently at around a 1000 or so. What I would like to do is change how the engine scores hits on a document, from the current default. Zend_Search_Lucene scores on the frequency of number of hits within a document, so a document that has 10 matches of the word PHP will score higher than a document with only 3 matches of PHP. What I am trying to do is pass a number of key words and score depending on the hits of those keywords. e.g. I pass 5 key words say,PHP, MySQL, Javascript, HTML and CSS that I search against the index. One document has 3 matches to those key words and one document has all 4 matches, the 4 matches scores the highest. The number of instances of those words in the document do not concern me. Now I've had a quick look at Zend_Search_Lucene_Search_Similarity however I have to confess that I am not sure (or that bright) to know how to use this to achieve what I am after. Is what I want to do possible using Lucene or is there a better solution out there?

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• Drupal 6: Group multiple values in tpl.php

  - by Jozzeh

  When using the date and views module, you can specify in views (using row style fields) 'group multiple values'. Which is default on. If you turn it off, you get multiple nodes each with a date. For example: - 24th March ------- node1 - 25th March ------- node1 What I'm trying to figure out is: what if you are not using fields but node as Row style. How do you implement this not-group-multiple-values in your type-node.tpl.php?

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• How to refactor this duplicated LINQ code?

  - by benrick

  I am trying to figure out how to refactor this LINQ code nicely. This code and other similar code repeats within the same file as well as in other files. Sometime the data being manipulated is identical and sometimes the data changes and the logic remains the same. Here is an example of duplicated logic operating on different fields of different objects. public IEnumerable<FooDataItem> GetDataItemsByColor(IEnumerable<BarDto> dtos) { double totalNumber = dtos.Where(x => x.Color != null).Sum(p => p.Number); return from stat in dtos where stat.Color != null group stat by stat.Color into gr orderby gr.Sum(p => p.Number) descending select new FooDataItem { Color = gr.Key, NumberTotal = gr.Sum(p => p.Number), NumberPercentage = gr.Sum(p => p.Number) / totalNumber }; } public IEnumerable<FooDataItem> GetDataItemsByName(IEnumerable<BarDto> dtos) { double totalData = dtos.Where(x => x.Name != null).Sum(v => v.Data); return from stat in dtos where stat.Name != null group stat by stat.Name into gr orderby gr.Sum(v => v.Data) descending select new FooDataItem { Name = gr.Key, DataTotal = gr.Sum(v => v.Data), DataPercentage = gr.Sum(v => v.Data) / totalData }; } Anyone have a good way of refactoring this?

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• Is this an acceptable use of "ASCII arithmetic"?

  - by jmgant

  I've got a string value of the form 10123X123456 where 10 is the year, 123 is the day number within the year, and the rest is unique system-generated stuff. Under certain circumstances, I need to add 400 to the day number, so that the number above, for example, would become 10523X123456. My first idea was to substring those three characters, convert them to an integer, add 400 to it, convert them back to a string and then call replace on the original string. That works. But then it occurred to me that the only character I actually need to change is the third one, and that the original value would always be 0-3, so there would never be any "carrying" problems. It further occurred to me that the ASCII code points for the numbers are consecutive, so adding the number 4 to the character "0", for example, would result in "4", and so forth. So that's what I ended up doing. My question is, is there any reason that won't always work? I generally avoid "ASCII arithmetic" on the grounds that it's not cross-platform or internationalization friendly. But it seems reasonable to assume that the code points for numbers will always be sequential, i.e., "4" will always be 1 more than "3". Anybody see any problem with this reasoning? Here's the code. string input = "10123X123456"; input[2] += 4; //Output should be 10523X123456

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• Multiple Solution Layout for ASP.NET Web Portal?

  - by Jared S

  At work, we've developed a custom ASP.NET Web Portal (That's very similar to iGoogle). We have "Apps" (self-contained, large web forms) and "Modules" (similar to Google Gadgets). Currently, we use a single-solution model. Right now, we have: 3 core projects 60 application projects 80 module projects To reduce copy and pasting between projects, we're going to factor out common functionality (Data Access, Business Logic) into separate projects. I'd also like to introduce Unit Tests, which is going to increase the number of projects even more. We've already reached the point where Visual Studio is choking on the number of projects. We generally only load the 3 core projects and then whatever app's/module's project we're working on. Would a different solution structure help us out? Our number of projects is only going to increase. In general, an app or module only references the 3 core projects. Soon, apps/modules may start referencing the Data Access/Business Logic projects. But in general, apps and modules do not make references between themselves. So to recap, what is the best practice for solution structure when there are MANY projects that use a small number of core projects?

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• Adding a onclick event to a code generated html element via object initializer

  - by mwright

  I would like to be able to add a click event to a entity generated in the code behind. Currently I'm doing it like this: TableRow row = new TableRow(); row.Attributes.Add("onclick", "clickFunction(this)"); Is there a way to do this using the object initializer? I am doing a lot of control creation/initialization and if it matched the rest of the code it would be nice

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• Updating value in Linq to SQL IEnumerable

  - by Learner

  Using Linq to SQL: if(!parentlist.childlist.Contains(row1)) parentlist.childlist.Add(row1); else How do I update the required childlist row with row1? Each row of the child list has a unique id. parentlist implements IEnumerable and childlist is IList.

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• Information about PTE's (Page Table Entries) in Windows

  - by Patrick

  In order to find more easily buffer overflows I am changing our custom memory allocator so that it allocates a full 4KB page instead of only the wanted number of bytes. Then I change the page protection and size so that if the caller writes before or after its allocated piece of memory, the application immediately crashes. Problem is that although I have enough memory, the application never starts up completely because it runs out of memory. This has two causes: since every allocation needs 4 KB, we probably reach the 2 GB limit very soon. This problem could be solved if I would make a 64-bit executable (didn't try it yet). even when I only need a few hundreds of megabytes, the allocations fail at a certain moment. The second problem is the biggest one, and I think it's related to the maximum number of PTE's (page table entries, which store information on how Virtual Memory is mapped to physical memory, and whether pages should be read-only or not) you can have in a process. My questions (or a cry-for-tips): Where can I find information about the maximum number of PTE's in a process? Is this different (higher) for 64-bit systems/applications or not? Can the number of PTE's be configured in the application or in Windows? Thanks, Patrick PS. note for those who will try to argument that you shouldn't write your own memory manager: My application is rather specific so I really want full control over memory management (can't give any more details) Last week we had a memory overwrite which we couldn't find using the standard C++ allocator and the debugging functionality of the C/C++ run time (it only said "block corrupt" minutes after the actual corruption") We also tried standard Windows utilities (like GFLAGS, ...) but they slowed down the application by a factor of 100, and couldn't find the exact position of the overwrite either We also tried the "Full Page Heap" functionality of Application Verifier, but then the application doesn't start up either (probably also running out of PTE's)

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• Parent Child using DataGrid SilverLight 3.0

  - by Asim Sajjad

  Can anyone have idea to show DataGrid in the RowDetail of the Row in the dataGrid, I want to show datagrid in the detail of the grid row. thanks in advance

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• How to retrieve last primary Id from mdb's table?

  - by William

  I got table with next columns: Id, Name, Age, Class I am trying to insert new row in db like this: INSERT INTO MyTable (Name, Age, Class) VALUES (@name, @age, @class) And get an exeption: "Index or primary key cannot contain a Null value." The question is how to add a new row without knowing next primary Id, or maybe there is a way to get this Id from the table with the help of another query ?

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• C programming - How to print numbers with a decimal component using only loops?

  - by californiagrown

  I'm currently taking a basic intro to C programming class, and for our current assignment I am to write a program to convert the number of kilometers to miles using loops--no if-else, switch statements, or any other construct we haven't learned yet are allowed. So basically we can only use loops and some operators. The program will generate three identical tables (starting from 1 kilometer through the input value) for one number input using the while loop for the first set of calculations, the for loop for the second, and the do loop for the third. I've written the entire program, however I'm having a bit of a problem with getting it to recognize an input with a decimal component. Here is what I have for the while loop conversions: #include <stdio.h> #define KM_TO_MILE .62 main (void) { double km, mi, count; printf ("This program converts kilometers to miles.\n"); do { printf ("\nEnter a positive non-zero number"); printf (" of kilometers of the race: "); scanf ("%lf", &km); getchar(); }while (km <= 1); printf ("\n KILOMETERS MILES (while loop)\n"); printf (" ========== =====\n"); count = 1; while (count <= km) { mi = KM_TO_MILE * count; printf ("%8.3lf %14.3lf\n", count, mi); ++count; } getchar(); } The code reads in and converts integers fine, but because the increment only increases by 1 it won't print a number with a decimal component (e.g. 3.2, 22.6, etc.). Can someone point me in the right direction on this? I'd really appreciate any help! :)

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• Insert Registration Data in MySQL using PHP

  - by J M 4

  I may not be asking this in the best way possible but i will try my hardest. Thank you ahead of time for your help: I am creating an enrollment website which allows an individual OR manager to enroll for medical testing services for professional athletes. I will NOT be using the site as a query DB which anybody can view information stored within the database. The information is instead simply stored, and passed along in a CSV format to our network provider so they can use as needed after the fact. There are two possible scenarios: Scenario 1 - Individual Enrollment If an individual athlete chooses to enroll him/herself, they enter their personal information, submit their payment information (credit/bank account) for processing, and their information is stored in an online database as Athlete1. Scenario 2 - Manager Enrollment If a manager chooses to enroll several athletes he manages/ promotes for, he enters his personal information, then enters the personal information for each athlete he wishes to pay for (name, address, ssn, dob, etc), then submits payment information for ALL athletes he is enrolling. This number can range from 1 single athlete, up to 20 athletes per single enrollment (he can return and complete a follow up enrollment for additional athletes). Initially, I was building the database to house ALL information regardless of enrollment type in a single table which housed over 400 columns (think 20 athletes with over 10 fields per athlete such as name, dob, ssn, etc). Now that I think about it more, I believe create multiple tables (manager(s), athlete(s)) may be a better idea here but still not quite sure how to go about it for the following very important reasons: Issue 1 If I list the manager as the parent table, I am afraid the individual enrolling athlete will not show up in the primary table and will not be included in the overall registration file which needs to be sent on to the network providers. Issue 2 All athletes being enrolled by a manager are being stored in SESSION as F1FirstName, F2FirstName where F1 and F2 relate to the id of the fighter. I am not sure technically speaking how to store multiple pieces of information within the same table under separate rows using PHP. For example, all athleteswill have a first name. The very basic theory of what i am trying to do is: If number_of_athletes 1, store F1FirstName in row 1, column 1 of Table "Athletes"; store F1LastName in row 1, column 2 of Table "Athletes"; store F2FirstName in row 2, column 1 of Table "Athletes"; store F2LastName in row 2, column 2 of table "Athletes"; Does this make sense? I know this question is very long and probably difficult so i appreciate the guidance.

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• DBD::CSV: Problem with userdefined functions

  - by sid_com

  From the SQL::Statement::Functions documentation: Creating User-Defined Functions ... More complex functions can make use of a number of arguments always passed to functions automatically. Functions always receive these values in @_: sub FOO { my( $self, $sth, $rowhash, @params ); } #!/usr/bin/env perl use 5.012; use warnings; use strict; use DBI; my $dbh = DBI->connect( "DBI:CSV:", undef, undef, { RaiseError => 1, } ); my $table = 'wages'; my $array_ref = [ [ 'id', 'number' ], [ 0, 6900 ], [ 1, 3200 ], [ 2, 1800 ], ]; $dbh->do( "CREATE TEMP TABLE $table AS import( ? )", {}, $array_ref ); sub routine { my $self = shift; my $sth = shift; my $rowhash = shift; # return $_[0] / 30; }; $dbh->do( "CREATE FUNCTION routine" ); my $sth = $dbh->prepare( "SELECT id, routine( number ) AS result FROM $table" ); $sth->execute(); $sth->dump_results(); When I try this I get an error-message: DBD::CSV::st execute failed: Use of uninitialized value $_[0] in division (/) at ./so.pl line 27. [for Statement "SELECT id, routine( number ) AS result FROM "wages""] at ./so.pl line 34. When I comment out the third argument I works as expected ( because it looks as if the third argument is missing ): #!/usr/bin/env perl ... sub routine { my $self = shift; my $sth = shift; #my $rowhash = shift; return $_[0] / 30; }; ... 0, 230 1, 106.667 2, 60 3 rows Is this a bug?

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• Call to a member function fetch_assoc() on a non-object

  - by Joann

  I'm a super beginner. I did find related questions here but I think they're too advanced for my skills. :-( Here's my function: function get_fname($un){ $registerquery = $this->conn->query("SELECT f_name FROM tz_members WHERE usr='".$un."'"); while ($row = $registerquery->fetch_assoc()) { return $fname = $row[$un]; } } Any help plsss??

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• Delphi: EInvalidOp in neural network class (TD-lambda)

  - by user89818

  I have the following draft for a neural network class. This neural network should learn with TD-lambda. It is started by calling the getRating() function. But unfortunately, there is an EInvalidOp (invalid floading point operation) error after about 1000 iterations in the following lines: neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda Why is this error? I can't find the mistake in my code :( Can you help me? Thank you very much in advance! unit uNeuronalesNetz; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, StdCtrls, Grids, Menus, Math; const NEURONS_INPUT = 43; // number of neurons in the input layer NEURONS_HIDDEN = 60; // number of neurons in the hidden layer NEURONS_OUTPUT = 1; // number of neurons in the output layer NEURONS_TOTAL = NEURONS_INPUT+NEURONS_HIDDEN+NEURONS_OUTPUT; // total number of neurons in the network MAX_TIMESTEPS = 42; // maximum number of timesteps possible (after 42 moves: board is full) LEARNING_RATE_INPUT = 0.25; // in ideal case: decrease gradually in course of training LEARNING_RATE_HIDDEN = 0.15; // in ideal case: decrease gradually in course of training GAMMA = 0.9; LAMBDA = 0.7; // decay parameter for eligibility traces type TFeatureVector = Array[1..43] of SmallInt; // definition of the array type TFeatureVector TArtificialNeuralNetwork = class // definition of the class TArtificialNeuralNetwork private // GENERAL SETTINGS START learningMode: Boolean; // does the network learn and change its weights? // GENERAL SETTINGS END // NETWORK CONFIGURATION START neuronsInput: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_INPUT] of Extended; // array of all input neurons (their values) for every timestep neuronsHidden: Array[1..NEURONS_HIDDEN] of Extended; // array of all hidden neurons (their values) neuronsOutput: Array[1..NEURONS_OUTPUT] of Extended; // array of output neurons (their values) weightsInput: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Extended; // array of weights: input->hidden weightsHidden: Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of weights: hidden->output // NETWORK CONFIGURATION END // LEARNING SETTINGS START outputBefore: Array[1..NEURONS_OUTPUT] of Extended; // the network's output value in the last timestep (the one before) eligibilityTraceHidden: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of eligibility traces: hidden layer eligibilityTraceOutput: Array[1..NEURONS_TOTAL] of Array[1..NEURONS_TOTAL] of Extended; // array of eligibility traces: output layer reward: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_OUTPUT] of Extended; // the reward value for all output neurons in every timestep tdError: Array[1..NEURONS_OUTPUT] of Extended; // the network's error value for every single output neuron t: Byte; // current timestep cyclesTrained: Integer; // number of cycles trained so far (learning rates could be decreased accordingly) last50errors: Array[1..50] of Extended; // LEARNING SETTINGS END public constructor Create; // create the network object and do the initialization procedure UpdateEligibilityTraces; // update the eligibility traces for the hidden and output layer procedure tdLearning; // learning algorithm: adjust the network's weights procedure ForwardPropagation; // propagate the input values through the network to the output layer function getRating(state: TFeatureVector; explorative: Boolean): Extended; // get the rating for a given state (feature vector) function HyperbolicTangent(x: Extended): Extended; // calculate the hyperbolic tangent [-1;1] procedure StartNewCycle; // start a new cycle with everything set to default except for the weights procedure setLearningMode(activated: Boolean=TRUE); // switch the learning mode on/off procedure setInputs(state: TFeatureVector); // transfer the given feature vector to the input layer (set input neurons' values) procedure setReward(currentReward: SmallInt); // set the reward for the current timestep (with learning then or without) procedure nextTimeStep; // increase timestep t function getCyclesTrained(): Integer; // get the number of cycles trained so far procedure Visualize(imgHidden: Pointer); // visualize the neural network's hidden layer end; implementation procedure TArtificialNeuralNetwork.UpdateEligibilityTraces; var i, j, k: Integer; begin // how worthy is a weight to be adjusted? for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := LAMBDA*eligibilityTraceOutput[j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*neuronsHidden[j]; for i := 1 to NEURONS_INPUT do begin eligibilityTraceHidden[i][j][k] := LAMBDA*eligibilityTraceHidden[i][j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*weightsHidden[j][k]*neuronsHidden[j]*(1-neuronsHidden[j])*neuronsInput[t][i]; end; end; end; end; procedure TArtificialNeuralNetwork.setReward; VAR i: Integer; begin for i := 1 to NEURONS_OUTPUT do begin // +1 = player A wins // 0 = draw // -1 = player B wins reward[t][i] := currentReward; end; end; procedure TArtificialNeuralNetwork.tdLearning; var i, j, k: Integer; begin if learningMode then begin for k := 1 to NEURONS_OUTPUT do begin if reward[t][k] = 0 then begin tdError[k] := GAMMA*neuronsOutput[k]-outputBefore[k]; // network's error value when reward is 0 end else begin tdError[k] := reward[t][k]-outputBefore[k]; // network's error value in the final state (reward received) end; for j := 1 to NEURONS_HIDDEN do begin weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := weightsInput[i][j]+LEARNING_RATE_INPUT*tdError[k]*eligibilityTraceHidden[i][j][k]; // adjust input->hidden weights according to TD-lambda end; end; end; end; end; procedure TArtificialNeuralNetwork.ForwardPropagation; var i, j, k: Integer; begin for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for i := 1 to NEURONS_INPUT do begin neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden end; neuronsHidden[j] := HyperbolicTangent(neuronsHidden[j]); // activation of hidden neuron j end; for k := 1 to NEURONS_OUTPUT do begin neuronsOutput[k] := 0; for j := 1 to NEURONS_HIDDEN do begin neuronsOutput[k] := neuronsOutput[k]+neuronsHidden[j]*weightsHidden[j][k]; // hidden -> output end; neuronsOutput[k] := HyperbolicTangent(neuronsOutput[k]); // activation of output neuron k end; end; procedure TArtificialNeuralNetwork.setLearningMode; begin learningMode := activated; end; constructor TArtificialNeuralNetwork.Create; var i, j, k: Integer; begin inherited Create; Randomize; // initialize random numbers generator learningMode := TRUE; cyclesTrained := -2; // only set to -2 because it will be increased twice in the beginning StartNewCycle; for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin weightsHidden[j][k] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; end; for i := 1 to 50 do begin last50errors[i] := 0; end; end; procedure TArtificialNeuralNetwork.nextTimeStep; begin t := t+1; end; procedure TArtificialNeuralNetwork.StartNewCycle; var i, j, k, m: Integer; begin t := 1; // start in timestep 1 cyclesTrained := cyclesTrained+1; // increase the number of cycles trained so far for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := 0; outputBefore[k] := 0; neuronsOutput[k] := 0; for m := 1 to MAX_TIMESTEPS do begin reward[m][k] := 0; end; end; for i := 1 to NEURONS_INPUT do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceHidden[i][j][k] := 0; end; end; end; end; function TArtificialNeuralNetwork.getCyclesTrained; begin result := cyclesTrained; end; procedure TArtificialNeuralNetwork.setInputs; var k: Integer; begin for k := 1 to NEURONS_INPUT do begin neuronsInput[t][k] := state[k]; end; end; function TArtificialNeuralNetwork.getRating; begin setInputs(state); ForwardPropagation; result := neuronsOutput[1]; if not explorative then begin tdLearning; // adjust the weights according to TD-lambda ForwardPropagation; // calculate the network's output again outputBefore[1] := neuronsOutput[1]; // set outputBefore which will then be used in the next timestep UpdateEligibilityTraces; // update the eligibility traces for the next timestep nextTimeStep; // go to the next timestep end; end; function TArtificialNeuralNetwork.HyperbolicTangent; begin if x > 5500 then // prevent overflow result := 1 else result := (Exp(2*x)-1)/(Exp(2*x)+1); end; end.

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