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# Questions tagged [linear-algebra]

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19 views

### Fourier Dimension of Boolean functions

I was recently reading about Fourier dimension of Boolean functions. What I understand is that if we take the Fourier expansion of $f: \{\pm1\}^n \to \{\pm1\}$ and consider the monomials with non zero ...
1 vote
152 views

### Clarification regarding linear boolean functions!

I am a little confused when it comes to linear boolean functions. According to this post: What is a simple way of explaining what a linear boolean function means in boolean algebra and relating it to ...
1 vote
29 views

### Complexity of finding $d$ largest eigenvectors of a symmetric matrix

I know that for $n \times n$ matrix, it takes $O(n^2)$ time complexity to compute the largest eigenpair of the matrix using Power method or etc. I'm interested to further extend the case so that now ...
22 views

29 views

### Finding a $d$-dimensional hyperplane containing $n$ given points

I'm currently trying to find the equation of the $d$-dimensional hyperplane which includes $n$ given points, where $n \ge d$. Theoretically, it isn't hard - the $d$-dimensional hyperplane is ...
1 vote
20 views

### Algorithmic ideas to multiply two tall & skinny matrices into one large square matrix?

This problems comes from AI, and it looks something like this: I am supposed to multiply two floating-point matrices A * B. A ...
21 views

### Is one set of vectors constructed by another set of vectors?

Let there be given set of vectors $V = \{v_1, v_2, ..., v_n\}$ and set of vectors $S = \{s_1, s_2, ..., s_k\}$ where $n > k$. The set of vectors $V$ can be constructed by $S$ if the vectors in $V$ ...
42 views

### Which of these algorithms will involve the least amount of math?

I'm taking an algorithms class for my computer science degree, and one of the requirements is to research and present 3 different algorithms. The only problem: linear algebra wasn't a prerequisite to ...
42 views

### Finding a set of 9 integers that minimize an error function

I have an algorithm that takes a 3d triangle PMN(which is constructed from running a function that converts per-vertex UV coordinates to a PMN triangle) and P' which is a randomly chosen 3D point that ...
94 views

### Optimization problem with discrete and continuous components

Suppose we have a sequence of $m$ tokens $(T_1, T_2, \ldots, T_m)$. We can split this sequence considering two parameters $w$ (which is the width of the window) and $x$ which is the overlap between ...
25 views

### Kalman Filter - Dynamic System

Given the two equations below \begin{aligned} 300x + 400y &= 700 \\ 100x + 133y &= 233 \end{aligned} how can one find a solution for those equations using Kalman filter (and suppose the ...
41 views

### Bound on the number of signed sums of a non-zero vector that can all equal zero

Let $u$ be a real vector of $m$ entries, and $A$ be a $\pm 1$ matrix of dimension $N\times m$, and real rank $\operatorname{rank}(A) = r$. What are some conditions on $A$ (e.g. in terms of its rank $r$...
33 views

### can similarity transformation be linear transformation?

Learning Computer Graphics - Can similarity transformation be linear transformation? Similarity T is a rigid transformation (translation and rotations) with uniform scaling. so I guess a similarity ...
48 views

### What is this linear optimization problem?

Given a $d$-dimensional vector $v = (v_1,\dots,v_d) \in \Bbb{R}^d$, we define $f(v) = \min_{i\in [d]} \{v_i\}$ to be the smallest coordinate of $v$. Let $v^1,\dots,v^n \in \Bbb{R}^d_{\ge 0}$ be non-...
25 views

### How to eliminate « a priori » all vectors in a list of vectors whose scalar product with a given vector is zero without calculating the product

How to eliminate « a priori » all vectors in a list of vectors, whose scalar product with a given vector is zero, without actually calculating the product ? One solution would be to store the ...
43 views

### Recommendations on where to learn and practice linear programming?

[CLOSED] Thanks! I am studying Linear Programming in college but I am facing some difficulties to assimilate some concepts. So do you have any recommendations of materials to learn or practice Linear ...
24 views

### Lower bound on number of zero columns in matrix

I've been looking for an algorithm to tell the number of non-zero rows (or columns) in a row reduces matrix $A\in \mathbb{R}^{m\times n}$. A simple approach would be to check it, row by row, which ...
31 views

### Best grid/lines to map a group of points

The data I have is a group of points with their position (x,y) known: It is known that all these red dots are situated exactly on the lines which form a grid system like following: My object is to ...
1k views

### Why is the probability of a false positive not 0 for Freivald's Algorithm?

Freivald's algorithm (see the wiki) is a randomized algorithm for verifying whether the product of two $n \times n$-matrices $A$ and $B$ yields a given matrix $C$ (i.e. $AB = C$). The way this task is ...
223 views

### How to setup the Bellman Equation as a linear system of equation

I was watching a video on Reinforcement Learning by Andrew Ng, and at about minute 23 of the video he mentions that we can represent the Bellman equation as a linear system of equations. I am talking ...
21 views

### Calculating the shortest vector between a vector and a truncated cone

I am trying to understand a certain implementation of calculating the shortest vector between a vector and a truncated cone in 3D. The original idea is introduced in this paper. So if we have two ...
1 vote
155 views

### Fast computing of a matrix power for large integer values in C++

I'm working with squared matrices that can be quite large, for instance, a M = 50 x 50 matrix. My objective is to compute the power of the squared matrix ...
1 vote
31 views

### Least probability of collisions using rgb as a hash map

I need to rewrite a short utility library, to get it working with the Brave browser (My actual question isn't about brave per se.) canvas-color-tracker - example of it being used and src/index.js is ...
51 views

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### Coordinate descent for Lasso, Question about algorithm

I'm not sure why the algorithm computes $c_k$ with $\sum_{j \neq k} w_j x_{i, j}$. Why does one need to ignore the $k^{th}$ feature here? I'm not sure how this is derived. Is this the result of taking ...
1 vote
56 views

1 vote
45 views

### Complexity of Matrix Inversion when $n-2$ Eigenvalues are the same

Suppose we have a symmetric matrix $A \in \mathbb{R}^{n \times n}$ that has $n-2$ equal eigenvalues and the other two are distinct. Question: What would be the complexity of its inversion? On the ...
1 vote
29 views

### Math behind Multi-class linear discriminate analysis (LDA)

I have a question about Linear Discriminant Analysis (LDA) for the purpose of Dimensionality Reduction. So I understand for the algorithm to calculate for $k$ projection vector(s) you need to ...
170 views

### Applying SVD compression to integral point images

Suppose that we have an $m\times n$ matrix $A$ of rank $n$, whose entries are 8-bit unsigned integers obtained from a grayscale image. Now we want to apply SVD to $A$ and to use the first $k$ singular ...
1 vote
Let $A\in\mathbb{F}_2^{m\times n}$ and denote its nullspace as $V=\{x\in\mathbb{F}_2^m:xA=0\}$. The weight of a basis $B=\{b_1,\dots,b_l\}$ for $V$ is the total weight of vectors in the basis, denoted ...