Search Results

Search found 3365 results on 135 pages for 'math'.

Page 103/135 | < Previous Page | 99 100 101 102 103 104 105 106 107 108 109 110  | Next Page >

• How can I maximally partition a set?

  - by Gregory Higley

  I'm trying to solve one of the Project Euler problems. As a consequence, I need an algorithm that will help me find all possible partitions of a set, in any order. For instance, given the set 2 3 3 5: 2 | 3 3 5 2 | 3 | 3 5 2 | 3 3 | 5 2 | 3 | 3 | 5 2 5 | 3 3 and so on. Pretty much every possible combination of the members of the set. I've searched the net of course, but haven't found much that's directly useful to me, since I speak programmer-ese not advanced-math-ese. Can anyone help me out with this? I can read pretty much any programming language, from BASIC to Haskell, so post in whatever language you wish.

  Read the article

• Script Speed vs Memory Usage

  - by Doug Neiner

  I am working on an image generation script in PHP and have gotten it working two ways. One way is slow but uses a limited amount of memory, the second is much faster, but uses 6x the memory . There is no leakage in either script (as far as I can tell). In a limited benchmark, here is how they performed: -------------------------------------------- METHOD | TOTAL TIME | PEAK MEMORY | IMAGES -------------------------------------------- One | 65.626 | 540,036 | 200 Two | 20.207 | 3,269,600 | 200 -------------------------------------------- And here is the average of the previous numbers (if you don't want to do your own math): -------------------------------------------- METHOD | TOTAL TIME | PEAK MEMORY | IMAGES -------------------------------------------- One | 0.328 | 540,036 | 1 Two | 0.101 | 3,269,600 | 1 -------------------------------------------- Which method should I use and why? I anticipate this being used by a high volume of users, with each user making 10-20 requests to this script during a normal visit. I am leaning toward the faster method because though it uses more memory, it is for a 1/3 of the time and would reduce the number of concurrent requests.

  Read the article

• Interesting AS3 hash situation. Is it really using strict equality as the documentation says?

  - by Triynko

  AS3 Code: import flash.utils.Dictionary; var num1:Number = Number.NaN; var num2:Number = Math.sqrt(-1); var dic:Dictionary = new Dictionary( true ); trace(num1); //NaN trace(num2); //NaN dic[num1] = "A"; trace( num1 == num2 ); //false trace( num1 === num2 ); //false trace( dic[num1] ); //A trace( dic[num2] ); //A Concerning the key comparison method... "The Dictionary class lets you create a dynamic collection of properties, which uses strict equality (===) for key comparison. When an object is used as a key, the object's identity is used to look up the object, and not the value returned from calling toString() on it." If Dictionary uses strict equality, as the documentation states, then how is it that num1 === num2 is false, and yet dic[num1] resolves to the same hash slot as dic[num2]?

  Read the article

• Operational Transformation library?

  - by gamers2000

  I'm looking for a library that would allow me to synchronize text in real-time between multiple users (ala Google Docs). I've stumbled upon Operational Transformation, which seems to fit my needs. Having said that, I understand the gist of OT, but not the math nor implementation of OT. Thus, I was wondering if there was a drag'n'drop Javascript library that would hook into a text area, generate the transforms, then allow me to apply those transformations onto another client? (I've gotten the Etherpad source, but I can't make head or tails out of it. If anyone could point out how to leverage on Etherpad's OT implementation, that'll be great too!)

  Read the article

• checking whether 4 points in a plane define a square ??

  - by osabri

  how to check whether 4 points in the plane define a square? what's the function which given a point and a value of the area of a square as input parameters returns four squares(define a corresponding type) with sides parallel to the x axis and y axis this how i start: #include <stdio.h> #include<math.h> struct point{ float x; float y; } typedef struct point POINT; struct square{ struct point p1; struct point p2; struct point p3; struct point p4; } typedef struct square SQUARE; int main() { int point; printf("point coordinate"); printf("\n\n"); printf("enter data\n");

  Read the article

• Malicious javascript code in my website

  - by Depami

  I found this code in my website sourcecode: var _0xd28d=["\x5F\x30\x78\x33\x32\x6C\x73\x6A\x39","\x5F\x78\x6C\x74","\x5F\x78\x38\x66\x6B\x63\x33","\x66\x6C\x6F\x6F\x72","\x72\x61\x6E\x64\x6F\x6D","\x6C\x65\x6E\x67\x74\x68"];var _0x9ae4=[_0xd28d[0],12,_0xd28d[1],_0xd28d[2],2,31,Math,_0xd28d[3]];var _0xcd6e=[_0x9ae4[5],_0x9ae4[0],_0x9ae4[_0x9ae4[4]],_0x9ae4[3],4,_0xd28d[4]];var _0xr6g0={};_0xr6g0[_0xcd6e[2]]=0;_0xr6g0[_0x9ae4[4]]=function (){var _0x4c68x4={};_0x4c68x4[_0xd28d[0]]=_0x9ae4[0];do{_0x4c68x4[_0x9ae4[0]]+=_0x4c68x4[_0xd28d[0]][_0x9ae4[6][_0x9ae4[7]](_0x9ae4[6][_0xcd6e[5]]()*_0x4c68x4[_0xd28d[0]][_0xd28d[5]])];} while(_0x4c68x4[_0xd28d[0]][_0xd28d[5]]<_0xcd6e[0]);;_0x4c68x4[_0x4c68x4[_0x9ae4[0]]]=function (){_0xr6g0[_0xcd6e[2]]++;_0xr6g0[_0xcd6e[2]]%=_0x9ae4[1];return _0x4c68x4[_0x4c68x4[_0x9ae4[0]]];} ;return _0x4c68x4[_0x4c68x4[_0xcd6e[1]]];} ;_0xr6g0[_0x9ae4[_0xcd6e[4]]]()()()()()()()()()()()()()()()(); I was wondering, what is it?

  Read the article

• Integers in JavaScript

  - by muntoo

  I'm a beginner to Javascript so forgive me if I sound dumb because I learned some Javascript from W3Fools (which are really difficult tutorials - they don't explain anything I want to know, but everything I probably can guess from my experience with C++). I may be switching over to MDN, but if you can recommend any other tutorials, that be great. Anyways, so here's my question: I just read a few lines of this, and apparently: Numbers in JavaScript are "double-precision 64-bit format IEEE 754 values", according to the spec. This has some interesting consequences. There's no such thing as an integer in JavaScript, so you have to be a little careful with your arithmetic if you're used to math in C or Java. I've already seen that there are few of the data types (for variables) I'm used to from C++. But I didn't expect all numbers to automatically be floats. Isn't there any way to use integers, not float? Will a future version of JavaScript support ints?

  Read the article

• What to beware of reading old Numarray tutorials and examples?

  - by DarenW

  Python currently uses Numpy for heavy duty math and image processing. The earlier Numeric and Numarray are obsolete, but still today there are many tutorials, notes, sample code and other documentation using them. Some of these cover special topics of interest, some are well written but haven't been updated or replaced, or are otherwise of use. Quite a bit is the same between Numeric, Numarray and Numpy, so I usually get good mileage out these older docs. Ocassionaly, though, I run into a line of code that results in error. Not often enough to remember how to get around it, but usually I figure it out at the cost of some time. What are the main things to watch out for when relying on such older documentation for current Numpy use? Is there a list of how to translate the differences that exist?

  Read the article

• How should I compile boost library in a small project?

  - by Vincenzo

  I have a small project where I need just part of boost library, boost::regex in particular. This is what I've done so far: /include /boost /regex /math .. 189 dirs, files, etc. /lib /boost-regex c_regex_traits.cpp cpp_regex_traits.cpp .. ~20 .cpp files myprog.cpp In my Makefile I compile all boost-regex .cpp files one by one, producing .obj files. Next, I'm building my project by means of compiling myprog.cpp together with all that .obj files from /lib/boost/regex. The question is whether I'm doing everything correct? The size of my output file is rather big (~3.5Mb), while my code is extremely small (10 lines).

  Read the article

• Bit Flipping in Hex

  - by freyrs

  I have an 8 digit hexadecimal number of which I need certain digits to be either 0 or f. Given the specific place of the digits is there a quick way to generate the hex number with those places "flipped" to f. For example: flip_digits(1) = 0x000000f flip_digits(1,2,4) = 0x0000f0ff flip_digits(1,7,8) = 0xff00000f I'm doing this on an embedded device so I can't call any math libraries, I suspect it can be done with just bit shifts but I can't quite figure out the method. Any sort of solution (Python, C, Pseudocode) will work. Thanks in advance.

  Read the article

• Why are there so many floats in the Android API?

  - by Brian

  The default floating point type in Java is the double. If you hard code a constant like 2.5 into your program, Java makes it a double automatically. When you do an operation on floats or ints that could potentially benefit from more precision, the type is 'promoted' to a double. But in the Android API, everything seems to be a float from sound volumes to rectangle coordinates. There's a structure called RectF used in most drawing; the F is for float. It's really a pain for programmers who are casting promoted doubles back to (float) pretty often. Don't we all agree that Java code is messy and verbose enough as it is? Usually math coprocessors and accelerators prefer double in Java because it corresponds to one of the internal types. Is there something about Android's Dalvik VM that prefers floats for some reason? Or are all the floats just a result of perversion in API design?

  Read the article

• php, get an end date based on start date and number of months

  - by mike

  Hi! I need to calculate an end date based on todays date and a number of months. For example, todays date 04/01/2010 and the number of months is 6. Are there any functions I can use to do some math that would return "10/01/2010"? Also, I think it's important to note that I am storing the result in MySQL as a "DATETIME" so I guess I would have to do something with the time as well... ??? Thanks!

  Read the article

• LINQ Equivalent query

  - by GilliVilla

  I have a List<string> List<string> students; students.Add("123Rob"); students.Add("234Schulz"); and a Dictionary<string,string> Dictionary<string, string> courses = new Dictionary<string, string>(); courses .Add("Rob", "Chemistry"); courses .Add("Bob", "Math"); courses .Add("Holly", "Physics"); courses .Add("Schulz", "Botany"); My objective now is to get a List with the values - {Chemistry,Botany} . In other words, I am trying to get the LINQ equivalent of select value from [courses] where [courses].key in ( select [courses].key from courses,students where [students].id LIKE '%courses.key%' ) How should the LINQ query be framed?

  Read the article

• Simple 2 way encryption for C#

  - by Matt Dawdy

  I'm looking for very simple encrypt and decrypt functionality for some data. It's not mission critical. I need something to keep honest people honest, but something a little stronger than ROT13 or Base64. I'd prefer something that is already included in the .Net framework 2.0 so I don't have to worry about any external dependencies. Pre-emptive EDIT: I really don't want to have to mess around with public/private keys, etc. I don't know much about encryption, but I do enough to know that anything I wrote would be less than worthless...in fact, I'd probably screw up the math and make it trivial to crack.

  Read the article

• Putting $$s in the middle of an `equation` environment: why doesn't Latex complain?

  - by Charles Stewart

  I was surprised that the Latex code from a recent question didn't throw up any errors, and even more surprised on further investigation, that Crowley's explanation seems to be true. My intuition about the \begin{equation} ... \end{equation} code is clearly off, what's really going on? Consider this, slightly adapted code: \begin{equation} 1: e^{i\pi}+1=0 $$ 2: B\"ob $$ 3: e=mc^2 \end{equation} This seems to prove that Crowley's explanation of such code, namely that "What that code says to LaTeX is begin equation, end it, begin it again, typeset definition of tangens and end the equation" is right: lines 1&3 can only be typeset in maths mode, line 2 only in text mode. Shouldn't Latex see that the \end{equation} is ending a display math that wasn't started by the \begin{equation}?

  Read the article

• execute javascript before return in php

  - by user354051

  I do have a custom php script that validates captcha code and sends an email. If php script is sending a mail successfully then it returns "true". This is done by: if(!$Error){ echo "true"; exit; } Before returning true, I would like to execute a jQuery command that should refresh the captcha image. I shouldn't be doing this is client side as it might be risky from spammers point of view. To refresh the captcha image, The command is: jQuery('#captcha').attr('src', ('php/captcha/captchaimage_show.php?' + Math.random())); I need to call this command from within php scripts before return any results by "echo" Prashant

  Read the article

• calculate next line numbers

  - by osomanden

  Weird question I guess.. But I am not very math wiz - soo here goes.. I am trying to create a patterne (or variable patterns based on selection) based on x and y numbers (2 rows and 4 columns) and the direction of the counting of x numbers like: 1-2-3-4 5-6-7-8 That one is easy, when number of x-columns is reached, next line and continue x count. But with eg. this one (still 2 rows and 4 columns): 1-2-3-4 8-7-6-5 upsie.. what if it is eg. 3++ rows and still 4 columns? 1-2-3-4 8-7-6-5 9-10-11-12 what would be the formula for this - or other possible variations (teaser for variations): 9-10-11-12 8-7-6-5 1-2-3-4 or reversed

  Read the article

• What we call this kind of chaining in C#

  - by Thinking

  Can you please tell me what kind of construct in C# is this. Code Golf: Numeric equivalent of an Excel column name C.WriteLine(C.ReadLine() .Reverse() .Select((c, i) => (c - 64) * System.Math.Pow(26, i)) .Sum()); Though I am new to C# (only two months exp so far), but since the time I have joined a C# team, I have never seen this kind of chaining. It really attracted me and I want to learn more about it. Please give some insight about this.

  Read the article

• Values of Variables Matrix NumPy

  - by Max Mines

  I'm working on a program that determines if lines intersect. I'm using matrices to do this. I understand all the math concepts, but I'm new to Python and NumPy. I want to add my slope variables and yint variables to a new matrix. They are all floats. I can't seem to figure out the correct format for entering them. Here's an example: import numpy as np x = 2 y = 5 w = 9 z = 12 I understand that if I were to just be entering the raw numbers, it would look something like this: matr = np.matrix('2 5; 9 12') My goal, though, is to enter the variable names instead of the ints.

  Read the article

• Type parameterization in Scala

  - by horatius83

  So I'm learning Scala at the moment, and I'm trying to create an abstract vector class with a vector-space of 3 (x,y,z coordinates). I'm trying to add two of these vectors together with the following code: package math class Vector3[T](ax:T,ay:T,az:T) { def x = ax def y = ay def z = az override def toString = "<"+x+", "+y+", "+z+">" def add(that: Vector3[T]) = new Vector3(x+that.x, y+that.y, z+that.z) } The problem is I keep getting this error: error: type mismatch; found : T required: String def add(that: Vector3[T]) = new Vector3(x+that.x, y+that.y, z+that.z) I've tried commenting out the "toString" method above, but that doesn't seem to have any effect. Can anyone tell me what I'm doing wrong?

  Read the article

• jQuery sibling selector?

  - by Brett

  Hi, I have a table which I'm trying to do a pricing list, that auto-computes the tax component.. I'm getting the value from price_1, applying a math cal, and saving it to tax_1. I could read the number of the end of the id, but hopefully there is a cleaner way with jQuery. E.g. I would have a lot of fields like.. price_1 price_2 price_3 tax_1 tax_2 tax_3 etc... I can use the following code to call jQuery on change of a price, and get the value of that price. How do I update the tax field next to it? should I use a sibling selector or something?? $('#pricing').delegate("input", "change", function(){ $(this).val() /* the value of the price */; })

  Read the article

• Newbie programmer looking for a fun, small project (pref. C++/Python)

  - by Francisco P.

  Hello everyone, I have some experience in Scheme and C++ (read: a semester of each) I know the very basics of Python (used it for physics simulations with the Visual Python module). Can you recommend me some fun and small (i.e. don't take much time) projects on either Python or C++? I have no real preferences, just that it is fun :P Thanks for your time! PS: I've tried projecteuler and python challenge. Euler is good, but more about math than coding, and py challenge just didn't work for me.

  Read the article

• set div position to fixed after scrolling 100px?

  - by user1481850

  I tried to use the following function in order to set the div's position to 100 px from top after scrolling 100 px. <script src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript"> $(window).scroll(function(){ $("#header").css("top",Math.max(0,100-$(this).scrollTop())); }); </script> <div class="header" style="position:fixed;top:100px;background-color:red">something</div> it is not working(the div stick to it's fixed position). it seems that the function is not relating to the div. what is my problem ?

  Read the article

• A 4-byte Unsigned Int for Sql Server 2008?

  - by Jeff Meatball Yang

  I understand there are multiple questions about this on SO, but I have yet to find a definitive answer of "yes, here's how..." So here it is again: What are the possible ways to store an unsigned integer value (32-bit value or 32-bit bitmap) into a 4-byte field in SQL Server? Here are ideas I have seen: 1) Use a -1*2^31 offset for all values Disadvantages: need to perform math on the values before reading/writing/aggregating. 2) Use 4 tinyint fields Disadvantages: need to concatenate values to perform any operations 3) Use binary(4) Disadvantages: actually uses 4 + 2 bytes of space

  Read the article

• converting char array into one int

  - by user1762517

  I can't use atoi, need to do it digit by digit.. How do I save it in a int.. given a char* temp put it all in one int.. #include <stdio.h> #include <string.h> #include <stdlib.h> #include <math.h> int main () { char* temp = "798654564654564654"; int i = 0; for (i = 0; i < strlen(temp); i++) { printf("%d", temp[i] - 48); } printf("\n"); }

  Read the article

< Previous Page | 99 100 101 102 103 104 105 106 107 108 109 110  | Next Page >