# Tagged Questions

261 views

### How to encode matrices uniquely

Given a square matrix $A=[a_{ij}]_{n \times n}$, an operation $swap(A, i, j)$ is defined to swap row $i$ and $j$ of $A$ and do the same thing with the corresponding columns. For example, in the ...
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### Meaning of the characteristic polynomial of a matroid

From wikipedia The characteristic polynomial of a matroid $M$ (which is sometimes called the chromatic polynomial,[29] although it does not count colorings), is defined to be  p_M(\lambda) ...
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### Performing matrix chain multiplication by hand

I'm trying to gain intuition for writing a matrix chain multiplication algorithm by working through a few problems by hand. I see plenty of worked-through solutions on sets of three or four solutions, ...
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### How can I understand 3d matrix coordinates in computer science

I know calculus but I have never ever touched on matrix...so I am always clueless. I get how you can multiply 2 matrices..but what you are getting even has mathematical significance is a mystery to ...
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### A problem on 0-1 matrices.

Given a 0-1 matrix $A$, is there an efficient way to find all 0-1 vectors $x$ such that $Ax = v$ where the entries of $v$ belong to a set $\{a,b\} \subseteq \mathbb{Z}$ of size $2$? Note that $v$ is ...
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### texture mapping from a camera image to a 3D surface acquired by a kinect

I have the following problem: A kinect camera capture a 3D surface and save it as a .obj files containing all the positions of the vertices (in the kinect coordinate system). If I take a picture ...
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### Homogeneous Arrays

I have this problem for homework and was wondering if anyone could help me out with it:
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### Given a N*M matrix determine the number of pairs that exist in a GLCM

This is an interesting problem for which I can't find a direct solution. Given a n*m matrix (in this case 5*5): 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 There exist a certain number of ...
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### Texture mapping from a camera image (knowing the camera pose)

I'm not sure if I should ask this question here or on stackoverflow, so forgive me if I'm wrong. I want to apply a texture (taken from a camera) on a 3D surface, let me explain my problem: I have ...
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### Are these equivalent representations (labelled graph and adjacency matrix)?

This is an example from Wikipedia's page on adjacency matrices, which from the site's format seems to be suggesting equivalence between the simple diagram below, left, and the abstractly represented ...
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### A an nxn matrix. P a permutation matrix that permutes columns of A. How many operations does P*A involve?

Essentially, I am supposed to count how many operations a particular computational algorithm involves, and I've gotten stuck on this one part. My understanding is that for two nxn matrices, matrix ...
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### Deriving the fundamental equation relationship

I'm having a hard time understanding how a few equations are being derived. So the fundamental equation is an equation that relates corresponding points in stereo images. Anyway, that's the basic ...
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### DCT and Inverse DCT Formulas

I'm implementing DCT, but I don't see the difference with the Inverse DCT formula. Both formula are on the Wikipedia page. The difference looks to be the normalization factor, but I don't see how to ...
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### Matrix Chain Multiplication?

The following are questions about using dynamic programming for matrix chain multiplication. Pseudocode can be found in the Wikipedia article on matrix chain multiplication. 1) Why is the time ...