Given the projection matrices from two cameras ($ P$ ,$ P’$ ) and a pair of corresponding points $ \{x_i,x’_i\}$ , it is straight forward to compute the triangulation using $ $ x_i=PX,x’_i=P’X$ $ .

I understand that a similar algebraic process can be used to find $ X$ using only the fundamental matrix $ F$ , as it also contains $ [T]_xR$ , but I could not develop such equation.

Does someone know the derivation of such a process?

# Tag: matrix

## Cutting matrix in 2 congruent pieces [closed]

I have a matrix with 0 and 1. The 1 resembles a pattern , a shape. Cut the shape in 2 congruent pieces and make it in the matrix with 2 and 3. In c++ and keep it simple pls

## Find if there is matrix that satisfying the following conditions

Given a matrix $ A_{n\times n} = \{a_{ij}\}$ such that $ a_{ij}$ is a non-negative number and given 2 vectors $ (r_1,r_2,…,r_n)$ , $ (c_1,c_2,…,c_n)$ such that $ r_i,c_i\in \mathbb{Z}$ define an efficient algorithm that will determine if there’s a matrix $ B_{n\times n} = \{b_{ij}\}$ , $ b_{ij} \in \mathbb{Z}$ and

for every $ 1\leq i \leq n \sum b_{ij} = r_i$

for every $ 1\leq j \leq n \sum b_{ij} = c_j$

and

$ 0 \leq b_{ij} \leq a_{ij}$

Thought something with dynamic programming but didn’t manage to solve it.

## Monopoly Matrix Coding

I am an IB student doing SL math. For my math IA i picked the topic of monopoly and the optimal way to play. However, in this IA there is a massive matrix that needs to be built to see how the long term possibilities of landing on a given square. I found someone’s code on this page https://arxiv.org/pdf/1410.1107.pdf, but I don’t know how to code it. I took a grade 11 course in computer science, but I barely know anything LOL. I used visual studio in this class, and I hope that I can use visual studio to code this. Can someone help? I have no idea if it’s possible. thanks guys!

## Boolean matrix / satisfiability problem [duplicate]

This question already has an answer here:

- How to enumerate minimal covers of a set 2 answers

Let $ M$ be an $ m\times n$ matrix with all elements in $ \{1,0\}$ , $ m >> n$ . Let $ \mathbf{v}_0, \ldots, \mathbf{v}_n$ be the columns of $ M$ .

I want to find all sets of columns $ S = \{\mathbf{v}_{i_1}, \ldots, \mathbf{v}_{i_k}\}$ so that for every row there is at least one column $ \mathbf{v}_{i_j}, \ldots, \mathbf{v}_{i_k}$ that has a $ 1$ in that row, with the constraint that $ S$ is minimal in the sense that deleting any element of $ S$ means $ S$ no longer meets these requirements.

Without the minimalness constraint, this is a trivial instance of (monotone) SAT – define a variable corresponding to each column of $ M$ , and just read the CNF clauses from the rows of $ M$ .

How can I approach the problem as described? I tried encoding the minimalness requirement as additional boolean constraints (which would make the problem regular SAT and I could use a SAT solver), but this gives $ n^m$ additional clauses in CNF form, which is intractably large.

## Find the minimal subset of rows of some matrix such that the sum of each column over this rows exceeds some threshold

Let $ A$ be a an $ n\times m$ real valued matrix. The problem is to find the minimal subset $ I$ of rows (if there is any) such that the sum of each column $ j$ over the corresponding rows exceeds some threshold $ t_j$ , i.e. $ \sum_{i\in I}A[i,j]>t_j$ for all $ j\in\{1,\dots m\}$ .

Or, stated as optimization problem:

Let $ A\in\mathbb{R}^{n\times m}, t\in\mathbb{R}^m$ . Now solve \begin{align}\min_{\xi\in\{0,1\}^n}&\sum_{i=1}^n\xi_i\\text{s.t.}&\,A^\top\xi>t\,.\end{align}

Actually, i would need a solution only for $ m=2$ , but the general might be interesting too.

## Matrix chain multiplication: Greedy approach

Edit; some suggested a thread in which the algorithm multiplies the 2 matrices with lowest values first. Mine is different: it divides by parenthesis the 2 matrices. And continues to the next section.

I have tried so many ways to disprove this one. This algorithm works like this: A= 5×2 B= 2×7 C= 7×3

First, find the lowest number in the lines / rows column. Then divide the sequence to 2: (A)(B•C) Then repeat the process for the 2 parts. Stop when you have 1 (or 2) matrices in the sequence. Is this algorithm optimal? It has to be better than N^3 (the usual algorithm)

## Merging 4 matrices to one matrix

I am struggling with the task to merge four matrices as presented below. Since the matrices A-D contain more than just four entries it would be too complex to do it by hand. Is there a simple or clever way to get the result in Mathematica?

A = `{{A11,A12}, {A21,A22}}`

B = `{{B11,B12}, {B21,B22}}`

C = `{{C11,C12}, {C21,C22}}`

D = `{{D11,D12}, {D21,D22}}`

E = `{{A11,B11,A12,B12}, {C11,D11,C12,D12}, {A21,B21,A22,B22}, {C21,D21,C22,D22}}`

Thanks in advance. 🙂

Max

## How to solve a matrix PDE and stop solving when solution becomes singular?

My question consists of two parts:

- How do I get mathematica to solve a PDE Matrix system and plot the result? See below for the PDE matrix system. (By plot the result I mean plot the region where the solution $ \Theta$ is nonsingular.)
- How do I stop the integration when the solution matrix becomes singular? I know that away from $ (x_1,x_2)=(0,0)$ the solution matrix $ \Theta$ will become singular how do I stop Mathematica from trying to solve pass this point?

The PDE matrix system I am trying to solve is \begin{align} \dot{\Theta}(x_1,x_2)+A&=\lambda \Theta(x_1,x_2) &\quad \text{Equation}\ \Theta(0,0)&=\begin{pmatrix} 1 & -\frac{1}{2} -\frac{\sqrt{3}}{2} \ 1 & -\frac{1}{2}-\frac{1}{2\sqrt{3}}+\frac{2}{\sqrt{3}} \end{pmatrix} &\quad \text{Initial condition} \end{align} I have specified the values of $ \dot{\Theta}(x_1,x_2),A,\lambda$ in the block below:

`(* Definitions *) A = {{-(x1^2 - 1), -2 x2 x1 - 1}, {1, 0}} lambda = {{1/2, -Sqrt[3]/2}, {Sqrt[3]/2, 1/2}} (*Value of theta for x1=x2=0 *) ThetaInit = {{1, -1/2 - Sqrt[3]/2}, {1, -1/2 - 1/(2 Sqrt[3]) + 2/Sqrt[3]}} (*Derative of Theta in terms of t. Note \ \frac{dtheta}{dt}=x1'(t)\frac{\partial theta}{\partial x1}+x2'(t) \ \frac{\partial theta}{\partial x2} *) ThetaDot = ( -(x1^2 - 1) x2 - x1) D[Theta[x1, x2], x1] + x2 D[Theta[x1, x2], x2] `

**Notes**

- If you need any clarification please feel free to ask.

## Matrix (array) c++

Make a program that accepts the number of matrix orders from the user, then assigns the values to the matrix according to the number of orders, the final step is to display the matrix that already contains the values. along with an explanation of the program from the lines.