intersection

PHP intersection between array and object

I have an object, let's say it's like this: class Foo { var $b, $a, $r; function __construct($B, $A, $R) { $this->b = $B; $this->a = $A; $this->r = $R; } } $f = new Foo(1, 2, 3); I want to get an arbitrary slice of this object's properties as an array. $desiredProperties = array('b', 'r'); $outp...

Finding intersection of two spheres

Hi, Consider the following problem - I am given 2 links of length L0 and L1. P0 is the point that the first link starts at and P1 is the point that I want the end of second link to be at in 3-D space. I am supposed to write a function that should take in these 3-D points (P0 and P1) as inputs and should find all configurations of the li...

Texture2D.Bounds.Intersect, but the Bounds never move? - XNA, .Net 4.0

Hi all, I am still shiny new to XNA, so please forgive any stupid question and statements in this post (The added issue is that I am using Visual Studio 2010 with .Net 4.0 which also means very few examples exist out on the web - well, none that I could find easily): I have two 2D objects in a "game" that I am using to learn more about ...

Single Column Multiple Filter In Mysql Intersection

Here is a table CarID| Attribute | Value 1 | Color | Red 2 | Color | Blue 3 | Color | Red 1 | Type | Coupe 2 | Type | Hatch Back 3 | Type | Coupe 3 | Make | Honda 2 | Make | Toyota 1 | Make | Ford Now I would like to run a filter Like Select * From Cars WHERE (Attribut...

Quickest algorithm for finding sets with high intersection

I have a large number of user IDs (integers), potentially millions. These users all belong to various groups (sets of integers), such that there are on the order of 10 million groups. To simplify my example and get to the essence of it, let's assume that all groups contain 20 user IDs. I want to find all pairs of integer sets that hav...

In SQL, a Join is actually an Intersection? And it is also a linkage or a "Sideway Union"?

I always thought of a Join in SQL as some kind of linkage between two tables. For example, select e.name, d.name from employees e, departments d where employees.deptID = departments.deptID In this case, it is linking two tables, to show each employee with a department name instead of a department ID. And kind of like a "linkage"...

In SQL, we can use "Union" to merge two tables. What are different ways to do "Intersection"?

In SQL, there is an operator to "Union" two tables. In an interview, I was told that, say one table has just 1 field with 1, 2, 7, 8 in it, and another table also has just 1 field with 2, and 7 in it, how do I get the intersection. I was stunned at first, because I never saw it that way. Later on, I found that it is actually a "Join" ...

Using ETS Select To Form An Intersection

i have the following ets structure: SomeTable = ets:new(sometable, [bag]). ets:insert(SomeTable, [ {set1,item1}, {set1,item2}, {set1,item3}, {set2,item1}, {set2,item2}, {set2,item4}]). i want ...

C#: 2D sub-Tile Line intersection

Hi, I have some problems getting an algorithm for my game to work and hope someone here can help me. Google didn't seem to be a good help as most solutions just work for full tiles. In the game units can occupy different positions inside a tile, i.e. they can be in the upper left corner, center, bottom right, ... position of tile (2/3),...

How to Find Intersections with Ellipses in PGF/TikZ

Hello, I am trying to display a sphere in PGF/TikZ to illustrate the idea of great circles. The code for my current result is: \begin{tikzpicture} \tikzfading[name=fade right, left color=transparent!20, right color=transparent!90] \tikzfading[name=fade out, inner color=transparent!100, outer color=transparent!10] \tikzfading[name=fa...

[Java] Efficiently finding the intersection of a variable number of sets of strings.

I have a variable number of ArrayList's that I need to find the intersection of. A realistic cap on the number of sets of strings is probably around 35 but could be more. I don't want any code, just ideas on what could be efficient. I have an implementation that I'm about to start coding but want to hear some other ideas. Currently, jus...

Take the intersection of an arbitrary number of lists in python

Suppose I have a list of lists of elements which are all the same (i'll use ints in this example) [range(100)[::4], range(100)[::3], range(100)[::2], range(100)[::1]] What would be a nice and/or efficient way to take the intersection of these lists (so you would get every element that is in each of the lists)? For the example that wou...

intersection regular expression with groups, how to derive the intersection of the grouped bit?

I'm currently trying to solve a problem that's similar to http://stackoverflow.com/questions/2338716/testing-intersection-of-two-regular-languages with the exception that I know how to do the intersection, but have an additional requirement. The intersection logic I intend to use is the Dragon Book's algorithm for converting an NFA to a...

Ray-triangle intersetion

Hello! How can I test intersesion ray and triangle, and if it exist how to get distance from ray origin to intersection point?? What optimization I can use, if in my program I've got to check 1 ray to ~10000 triangles ?? ...

set / line intersection solution

I have two lists in python and I want to know if they intersect at the same index. Is there a mathematical way of solving this? For example if I have [9,8,7,6,5] and [3,4,5,6,7] I'd like a simple and efficient formula/algorithm that finds that at index 3 they intersect. I know I could do a search just wondering if there is a better wa...

Great Circle & Rhumb line intersection

I have a Latitude, Longitude, and a direction of travel in degrees true north. I would like to calculate if I will intersect a line defined by two more Lat/Lon points. I figure the two points defining the line would create my great circle and my location and azimuth would define my Rhumb line. I am only interested in intersections tha...

how to intersect two "selects" and then put another condition for the result

I want to intersect two "select" queries and then put another condition for the whole result. I mean: (select ... intersect select ...) where ... is it possible? ...

problem with intersect operation in a sql query

I wrote the following query, I think it's correct but I have a "missing operator" error. SELECT * FROM results,Types WHERE results.a=Types.b INTERSECT SELECT * FROM results,Types WHERE results.c=Types.b Could somebody help me please? Thanks a lot. ...

Formula to determine if a line segment intersects a circle (flat)

Hi, Apologies if this is considered a repeat question, but the answers I've seen on here are too complex for my needs. I simply need to find out if a line segment intersects a circle. I don't need to find the distance to the line from the circle center, I don't need to solve for the points of intersection. The reason I need something...

How to intersect a Ray with a terrain model?

Hey, I am currently designing an RTS Game in XNA. So far I have a Terrain Model generated from a Heigthmap and some Units that are drawn on it. The next step would be to give the units commands on where to move. To do that I have to calculate the exact position of the terrain behind the cursor when it's clicked. For Units selection I ...