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Questions tagged [convex]

Anything related to convex geometric shapes. A shape in an Euclidean space is convex if, given two points A and B, every point of the segment AB belongs to the shape, i.e. AB is a subset of the shape.

Anything related to convex geometric shapes.

A shape in an Euclidean space is convex if, given two points A and B, every point of the segment AB belongs to the shape, i.e. AB is a subset of the shape.

See Wikipedia on:

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Convex Hull Rubberband idea - Only able to draw 4 lines

I've got a convex hull program going but the only issue left is that it only ever captures up to 4 points on the diagram. In a sense, if I were to make a 5th point, it would only replace one of the original 4 to keep the same 4 side limit. …
Psychosupreme
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Ascertain the pixels in a convex hull 2D

I have some pixels which representing already a convex hull, now I looking for a way to calculate these pixels to fill the convex hull. Is there any algorithm or idea which I should look at?
dot
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Non linear optimization in MATLAB

For the nonlinear optimization problem in two variables, say, x and y, how to check, if the function is smooth or not and is it medium scale or large scale problem. Should I use 'fmincon' solver (in MATLAB) as there is one linear constraint and…
Dr Nisha Arora
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How to solve this convex optimization?

It is simple, I know but I have little understanding of convex optimization yet Problem definition: Objective function is II b - Aw II norm 2 a vector of unknown [w1, w2, ..., wn] a data matrix A (m x n), each row has n components([ai1, ai2, ...,…
Hello lad
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Quickhull points not returned in correct order

I implemented the quick hull code found on the following page: http://www.ahristov.com/tutorial/geometry-games/convex-hull.html The algorithm is returning the correct points of the convex hull, but it is not returning them in the correct…
kkyr
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Determining if graph is convex

I am trying to determine whether a line drawn connecting a number of points is convex or not. The points can be plotted on x,y coordinates. Can this be done in a way other than essentially connecting each point to every other point and seeing if…
user3738516
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Java: Perimeter of a convex polygon

I have an ArrayList of some Point-s. It's guaranteed that the Points are part of a convex polygon. How can I calculate the perimeter of this convex polygon? Update: The Points in the ArrayList are out of any order Update 2: All the points are part…
makesz1
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Find double-tangent in a polyline defined by (x,y) points

I have `System.Windows.Media.Point3D collection representing a cross-section of a freeform object. It's always more or less shaped like a "seagull-wings", "M" pattern with two convex bulges and a "valley" in between. It's orientation in space is…
heltonbiker
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Subtraction and addition of convex polygons

I have two 2D convex polygons. I want to subtract one from the other one and add one to the other one The resulting polygon must be either concave or a - better - a set of convex polygons (e.g. triangles). Do you have any idea how I can accomplish…
Sebastian Barth
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algorithm like convex hull, but return the lower area polygon containing all points

I have a spatial software, In a database I have for each street in several cities, the lat/long of each street. And every street belongs to a zone. I'm trying to get polygons for each zone, and to do this, I need an algorithm that give me as result…
Ariel Larraburu
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algorithm like convex hull, but that return the lower area polygon containing all points

I have a spatial software, In a database I have for each street in several cities, the lat/long of each street. And every street belongs to a zone. I'm trying to get polygons for each zone, and to do this, I need an algorithm that give me as result…
Ariel Larraburu
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Checking convexity from outside

Is there any method or algorithm to determine convex (or non-convexity) property of a region from outside (perimeter) ? One way is plotting tangent line in each point of perimeter and discuss how many times this line intersect the perimeter points.…
Zakhar
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Convexity of a polygon C++?

How can i test if a polygon is convex or not only by knowing the points of the polygon with their coordonates in c++?
user2116010
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Determining the position of a point in relation to a given 3D surface

I'm trying to implement the Quick hull algorithm for computing the 3D convex hull. The problem is that I need to know if a point can "see" a given surface. The surface has a direction clockwise or counter clockwise direction. I wrote a small opengl…
Jonathan
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Capturing touch on concave/convex images with libgdx

I'm creating an app that uses libgdx in Android. I need to add a touch listener for when the end user clicks only on the visible part of a texture, whether it's concave or convex image. How can I do that? I remember that there is a nice idea (though…
android developer
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