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• Integration (math) in C++

  - by Chris Thompson

  Hi all, I'm looking for a library to find the integral of a given set of random data (rather than a function) in C++ (or C, but preferably C++). There is another question asking about integration in C but the answers discuss more how to integrate a function (I think...). I understand that this can be done simply by calculating the area under the line segment between each pair of points from start to finish, but I'd rather not reinvent the wheel if this has already been done. I apologize in advance if this is a duplicate; I searched pretty extensively to no avail. My math isn't as strong as I'd like it so it's entirely possible I'm using the wrong terminology. Thanks in advance for any help! Chris

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• I want to query whitepages.com 4,000 times, how to save the results?

  - by John Corbin

  I have an old customer list of 4,000 businesses. I want to determine if the phone numbers associated with each listing are still working (and therefore the business is probably still open). I can put each number in whitepages.com and check them one by one... but want to automate the results. I have looked at their API and can't digest it. I can form the correct query URL, but trying things like cURL -O doesn't work. I have access to Mac tools, Unix tools, and could try various javascript stuff if anyone could point me in the right direction... would even pay. Help? Thx

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• Dynamic programming: Find largest diamond (rhombus)

  - by Darksody

  I have a small program to do in Java. I have a 2D array filled with 0 and 1, and I must find the largest rhombus (as in square rotated by 90 degrees) and their numbers. Example: 0 1 0 0 0 1 1 0 1 1 1 0 1 0 1 1 1 1 0 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 Result: 1 1 1 1 1 1 1 1 1 1 1 1 1 The problem is similar to this SO question. If you have any idea, post it here.

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• How to use a proprety/value table in MySQL

  - by David

  I inherited a mysql database that has a table with columns like this: object_id, property, value It holds data like this: 1,first_name,Jane 1,last_name,Doe 1,age,10 1,color,red 2,first_name,Mike 2,last_name,Smith 2,age,20 2,color,blue 3,first_name,John 3,last_name,Doe 3,age,20 3,color,red ... Basically what I want to do is treat this table as a regular table. How would I get the id numbers (or all properties) of a person who is age 20 sorted by last and than first name? So far I have: SELECT object_id FROM table WHERE property = 'age' AND value = '20' union SELECT object_id FROM table WHERE property = 'color' AND value = 'red' But I'm not sure how to go about ordering the data. Thanks

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• Why won't this SQL CAST work?

  - by Kev

  I have a nvarchar(50) column in a SQL Server 2000 table defined as follows: TaskID nvarchar(50) NULL I need to fill this column with some random SQL Unique Identifiers (I am unable to change the column type to uniqueidentifier). I tried this: UPDATE TaskData SET TaskID = CAST(NEWID() AS nvarchar) but I got the following error: Msg 8115, Level 16, State 2, Line 1 Arithmetic overflow error converting expression to data type nvarchar. I also tried: UPDATE TaskData SET TaskID = CAST(NEWID() AS nvarchar(50)) but then got this error: Msg 8152, Level 16, State 6, Line 1 String or binary data would be truncated. I don't understand why this doesn't work but this does: DECLARE @TaskID nvarchar(50) SET @TaskID = CAST(NEW() AS nvarchar(50)) I also tried CONVERT(nvarchar, NEWID()) and CONVERT(nvarchar(50), NEWID()) but got the same errors.

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• How to sort a Ruby Hash by number value?

  - by dustmoo

  Hi everyone, I have a counter hash that I am trying to sort by count. The problem I am running into is that the default Hash.sort function sorts numbers like strings rather than by number size. i.e. Given Hash: metrics = {"sitea.com" => 745, "siteb.com" => 9, "sitec.com" => 10 } Running this code: metrics.sort {|a1,a2| a2[1]<=>a1[1]} will return a sorted array: [ 'siteb.com', 9, 'sitea.com', 745, 'sitec.com', 10] Even though 745 is a larger number than 9, 9 will appear first in the list. When trying to show who has the top count, this is making my life difficult. :) Any ideas on how to sort a hash (or an array even) by number value size? I appreciate any help.

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• Connection to DB2 in Python

  - by Mestika

  Hi, I'm trying to create a database connection in a python script to my DB2 database. When the connection is done I've to run some different SQL statements. I googled the problem and has read the ibm_db API (http://code.google.com/p/ibm-db/wiki/APIs) but just can't seem to get it right. Here is what I got so far: import sys import getopt import timeit import multiprocessing import random import os import re import ibm_db import time from string import maketrans query_str = None conn = ibm_db.pconnect("dsn=write","usrname","secret") query_stmt = ibm_db.prepare(conn, query_str) ibm_db.execute(query_stmt, "SELECT COUNT(*) FROM accounts") result = ibm_db.fetch_assoc() print result status = ibm_db.close(conn) but I get an error. I really tried everything (or, not everything but pretty damn close) and I can't get it to work. I just need to make a automatic test python script that can test different queries with different indexes and so on and for that I need to create and remove indexes a long the way. Hope someone has a solutions or maybe knows about some example codes out there I can download and study. Thanks Mestika

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• Removing whitespace between HTML elements when using line breaks

  - by Skilldrick

  I have a page with a row of about 10 imgs. For readability of the HTML, I want to put a linebreak in between each img tag, but doing so renders whitespace between the images, which I do not want. Is there anything I can do other than break in the middle of the tags rather than between them? Edit: Here is a screenshot of what I have so far. I would like the book spine images to display in random combinations, using PHP. This is why I need separate img tags.

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• asp.net mvc validation must be a number custom error

  - by Para

  Hi, I am new to asp.net and I have a problem. When the users insert in a editor for a decimal field something other than numbers, they get an error "Field name" is not a number. But I don't want them to receive this message I want them to receive another message. I have no problem with this with required and range validators. Is there any way for me to do this? I am not refering necessarily to changing the culture just displaying another message. Thanks.

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• VB.net Network Graph code/algorithm

  - by Jens

  For a school project we need to visualise a computer network graph. The number of computers with specific properties are read from an XML file, and then a graph should be created. Ad random computers are added and removed. Is there any open source project or algorithm that could help us visualising this in VB.net? Or would you suggest us to switch to java. Update: We eventually switched java and used the Jung libraries because this was easier for us to understand and implement.

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• How to do a range query

  - by Walter H

  I have a bunch of numbers timestamps that I want to check against a range to see if they match a particular range of dates. Basically like a BETWEEN .. AND .. match in SQL. The obvious data structure would be a B-tree, but while there are a number of B-tree implementations on CPAN, they only seem to implement exact matching. Berkeley DB has the same problem; there are B-tree indices, but no range matching. What would be the simplest way to do this? I don't want to use an SQL database unless I have to. Clarification: I have a lot of these, so I'm looking for an efficient method, not just grep over an array.

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• Use JavaScript to Replace Classname Value

  - by user1515425

  I want to replace every occurrence of the numbers with the string: ???. Here is an example string: <em>Chelsea</em> 1-4 Atletico Madrid How can I do this in JavaScript? <a href="https://www.google.com/url?sa=t&amp;source=web&amp;cd=9&amp;cad=rja&amp;ved=0CFEQtwIwCA&amp;url=http%3A%2F%2Fwww.whoateallthepies.tv%2Fchelsea%2F137070%2Fsuper-cup-chelsea-1-4-atletico-madrid-falcao-on-fire-as-blues-flop-in-monaco-photos-highlights.html&amp;rct=j&amp;q=chelsea&amp;ei=1odBUImpBIWA0AWM1oC4BA&amp;usg=AFQjCNEwdCCckt15XTkHSAf2fsUnGk9IJg&amp;sig2=IOrD6hfMrviW9ods0DG2dw" class="l" onmousedown="return rwt(this,'','0','','9','AFQjCNEwdCCckt15XTkHSAf2fsUnGk9IJg','IOrD6hfMrviW9ods0DG2dw','0CFEQtwIwCA',null,event)" title="Super Cup: Chelsea 1-4 Atletico Madrid – Falcao On Fire As Blues Flop In Monaco (Photos ...">Super Cup: <em>Chelsea</em> 1-4 Atletico Madrid – Falcao On <b>...</b></a> Thanks in advance.

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• CakePHP: How do I order results based on a 2-level deep association model?

  - by KcYxA

  I'm hoping I won't need to resort to custom queries. A related question would be: how do I retrieve data so that if an associated model is empty, no record is retrieved at all, as opposed to an empty array for an associated model? As an oversimplified example, say I have the following models: City -- Street -- House How do I sort City results by House numbers? How do I retrieve City restuls that have at least one House in it? I don't want a record with a city name and details and an empty House array as it messes up pagination results. CakePHP retrieves House records belonging to the Street in a separate query, so putting somthing like 'House.number DESC' into the 'order' field of the search query returns a 'field does not exist' error. Any ideas?

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• The fastest way to iterate through a collection of objects

  - by Trev

  Hello all, First to give you some background: I have some research code which performs a Monte Carlo simulation, essential what happens is I iterate through a collection of objects, compute a number of vectors from their surface then for each vector I iterate through the collection of objects again to see if the vector hits another object (similar to ray tracing). The pseudo code would look something like this for each object { for a number of vectors { do some computations for each object { check if vector intersects } } } As the number of objects can be quite large and the amount of rays is even larger I thought it would be wise to optimise how I iterate through the collection of objects. I created some test code which tests arrays, lists and vectors and for my first test cases found that vectors iterators were around twice as fast as arrays however when I implemented a vector in my code in was somewhat slower than the array I was using before. So I went back to the test code and increased the complexity of the object function each loop was calling (a dummy function equivalent to 'check if vector intersects') and I found that when the complexity of the function increases the execution time gap between arrays and vectors reduces until eventually the array was quicker. Does anyone know why this occurs? It seems strange that execution time inside the loop should effect the outer loop run time.

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• GA written in Java

  - by EnderMB

  I am attempting to write a Genetic Algorithm based on techniques I had picked up from the book "AI Techniques for Game Programmers" that uses a binary encoding and fitness proportionate selection (also known as roulette wheel selection) on the genes of the population that are randomly generated within the program in a two-dimensional array. I recently came across a piece of pseudocode and have tried to implement it, but have come across some problems with the specifics of what I need to be doing. I've checked a number of books and some open-source code and am still struggling to progress. I understand that I have to get the sum of the total fitness of the population, pick a random number between the sum and zero, then if the number is greater than the parents to overwrite it, but I am struggling with the implementation of these ideas. Any help in the implementation of these ideas would be very much appreciated as my Java is rusty.

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• Are there any widely-agreed upon guidelines for rating your language knowledge on a scale?

  - by DVK

  The question was imagined after a co-worker was complaining for an hour about some guy who could not answer basic Java questions on an interview after self-identifying himself as "8 out of 10" on Java. While that was an obvious fib, I personally always had major trouble defining my specific language skills on a sliding scale unless I'm given specific guidelines (remember 40 standard libraries by heart? Able to solve 10 random Project Euler problems in <30 mins each? Can write implementation of A, B and C data-structures from scratch in 30 mins? Know 30% of standard? Can answer 50% of questions on StackOverflow pertaining to the language?) So, I was wondering - is there some sort of commonly accepted methodology for translating such tangible benchmarks into "rate yourself on a language between 1-10"? "Kernighan gets an A, God gets a B, everyone else gets C and less" type jokes are not helpful :)

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• How Do I Pull Info from String

  - by Russ Bradberry

  I am trying to pull dynamics from a load that I run using bash. I have gotten to a point where I get the string I want, now from this I want to pull certain information that can vary. The string that gets returned is as follows: Records: 2910 Deleted: 0 Skipped: 0 Warnings: 0 Each of the number can and will vary in length, but the overall structure will remain the same. What I want to do is be able to get these numbers and load them into some bash variables ie: RECORDS=?? DELETED=?? SKIPPED=?? WARNING=?? In regex I would do it like this: Records: (\d*?) Deleted: (\d*?) Skipped (\d*?) Warnings (\d*?) and use the 4 groups in my variables.

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• Using the value of a variable as another variables name in Ruby

  - by hrickards

  Hi, I'm just starting out in learning Ruby and I've written a program that generates some numbers and assigns them to variables @one, @two, @three etc. The user can then specify a variable to change by inputting it's name (e.g one). I then need to do something like '@[valueofinout] = asd'. How would I do this, and is there a better way as the way I'm thinking of seems to be discouraged? I've found x = "myvar" myvar = "hi" eval(x) -> "hi" but I don't completely understand why the second line is needed. In my case would I use something like @one = "21" input = "one" input = "@" + input changeto = "22" eval(input) -> changeto Thanks

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• Is it bad use "display: table;" to organise a layout into 2 columns?

  - by Colen

  Hello, I am trying to make a 2 column layout, apparently the bane of CSS. I know you shouldn't use tables for layout, but I've settled on this CSS. Note the use of display: table etc. div.container { width: 600px; height: 300px; margin: auto; display: table; table-layout: fixed; } ul { white-space: nowrap; overflow: hidden; display: table-cell; width: 40%; } div.inner { display: table-cell; width: auto; } With this layout: <div class="container"> <ul> <li>First</li> <li>Second</li> <li>Third</li> </ul> <div class="inner"> <p>Hello world</p> </div> </div> This seems to work admirably. However, I can't help wondering - am I obeying the letter of the "don't use tables" rule, but not the spirit? I think it's ok, since there's no positioning markup in the HTML code, but I'm just not sure about the "right" way to do it. I can't use css float, because I want the columns to expand and contract with the available space. Please, stack overflow, help me resolve my existential sense of dread at these pseudo-tables.

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• Reading Character from Image

  - by Chinjoo

  I am working on an application which requires matching of numbers from a scanned image file to database entry and update the database with the match result. Say I have image- employee1.jpg. This image will have two two handwritten entries - Employee number and the amount to be paid to the employee. I have to read the employee number from the image and query the database for the that number, update the employee with the amount to be paid as got from the image. Both the employee number and amount to be paid are written inside two boxes at a specified place on the image. Is there any way to automate this. Basically I want a solution in .net using c#. I know this can be done using artificial neural networks. Any ideas would be much appreciated.

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• Only the last run in a for loop in Javascript works

  - by Mengfei Murphy

  Here is a for loop written by Javascript. It is trying to apply queries for websql. for (var i = 0; i < 10; i++){ db.transaction(function (tx){ tx.executeSql('INSERT INTO ProjSetsT (ProjID) VALUES (?);', [i]); }); } The attempt is obvious, I tried to add values "0, 1, 2, ... 9" into column ProjID in table ProjSetsT. It does not work. I only got the last element, i.e. "9" inserted, but not the first eight numbers. Is there any syntax mistakes?

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• Oracle - Is there any effects of not having a primary key on a table ?

  - by Sathya

  We use sequence numbers for primary keys on the tables. There are some tables where we dont really use the primary key for any querying purpose. But, we have Indexes on other columns. These are non-unique indexes. The queries use these non-primary key columns in the WHERE conditions. So, I dont really see any benefit of having a primary key on such tables. My experience with SQL 2000 was that, it used to replicate tables which had some primary key. Otherwise it would not. I am using Oracle 10gR2. I would like to know if there are any such side-effects of having tables that dont have primary key.

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• PHP Resize image down and crop using imagemagick

  - by mr12086

  I'm trying to downsize image uploaded by users at the time of upload. This is no problem but I want to get specific with sizes now. I'm looking for some advice on an algorithm im struggling to produce that will take any shape image - square or rectangle of any widths/heights and downsize it. This image needs to be downsized to a target box size (this changes but is stored in a variable).. So it needs to downsize the image so that both the width and height are larger than the width and height of the target maintaining aspect ratio. but only just.. The target size will be used to crop the image so there is no white space around the edges etc. I'm looking for just the algorithm behind creating the correct resize based on different dimension images - I can handle the cropping, even resizing in most cases but it fails in a few so i'm reaching out. I'm not really asking for PHP code more pseudo. Either is fine obviously. Thanks Kindly.

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• How to set Chrome's user script version number.

  - by Atli

  Hey. I've been wondering how I might set the version number displayed for user-scripts in Chrome's extension tab So far the obvious methods have failed: // ==UserScript== // @version 1.1.5 // @uso:version 1.1.5 // ==/UserScript== I know Greasemonkey for Firefox doesn't use a version value, but since Chrome actually displays a version number, I thought it might. Perhaps this is a feature that has not been implemented? Or maybe it was never intended to be there, but it is there because extensions have version numbers, and user-scripts are currently installed as extensions? (I'm using the Linux beta, version: 4.0.249.43, by the way) Thanks. Edit: Seems this is listed as an unconfirmed bug in the Chromium bug database (Issue 30760)

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• What does 'salt' refer to in string-to-key (s2k) specifier?

  - by WilliamKF

  What does 'salt' refer to in string-to-key (s2k) specifier? It appears to be a random number generator to shake things up, but I would like to know what 'salt' stands for? For example it is written: 3.6.1.2. Salted S2K This includes a "salt" value in the S2K specifier -- some arbitrary data -- that gets hashed along with the passphrase string, to help prevent dictionary attacks. Octet 0: 0x01 Octet 1: hash algorithm Octets 2-9: 8-octet salt value Salted S2K is exactly like Simple S2K, except that the input to the hash function(s) consists of the 8 octets of salt from the S2K specifier, followed by the passphrase. But salt is not defined, although its meaning seems clear.

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