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1 vote
0 answers
182 views

Efficiency of RREF algorithms

Compute the RREF of the following matrix :$$\begin{bmatrix}1&-1&2&-3&7\\4&0&3&1&9\\2&-5&1&0&-2\\3&-2&-2&10&-12\end{bmatrix}$$ My friend ...
DatBoi's user avatar
  • 4,055
3 votes
1 answer
368 views

Applications of matrix differentiation

I know that ordinary differentiation has many real world applications, from quantum physics to economics, but I cannot think of any real world applications of matrix differentiation. So, do any real ...
MathGeek's user avatar
  • 780
5 votes
1 answer
109 views

Standard matrices to test low rank decomposition

I am working on a low rank decomposition technique that is robust to different types of noise (gaussian, salt and pepper, poisson). For starters, I simulated such low rank matrices and have ...
Vishwanath's user avatar
3 votes
2 answers
824 views

What are the units of an inverse matrix?

As the title suggests. For example if I have a matrix $A = \begin{pmatrix} a & b\\ c& d \end{pmatrix}$ and all elements consist of variables with units $kg$ and then I take the inverse of ...
Hendrix13's user avatar
  • 165
0 votes
1 answer
238 views

Uses for eigenvalues of unitary matrices

The eigenvalues of a unitary matrix lie on the unit circle. What are some applications in which the eigenvalue distribution of the matrix is important? For instance, that the eigenvalues are clustered,...
overfull hbox's user avatar
3 votes
1 answer
183 views

How to get the integral of $\log(\det(A + Bt))$ w.r.t variable t?

Suppose we have two positive definite matrices $A$ and $B$, now I want to get the integral of: \begin{align} \int_{a}^{b} \log(\det(A + Bt)) dt ~~~~~~~~~~~~\text{for } a, b > 0 \end{align} ...
0o0o0o0's user avatar
  • 123
2 votes
2 answers
626 views

Matrix expressions for the oblique projection onto subspace L in the direction of subspace K

In the past, I have had to write 3D visualization programs where, in a natural way, oblique projections onto a plane where needed. Each time, I had to develop a specific routine. Later on, I ...
Jean Marie's user avatar
  • 83.9k
4 votes
8 answers
8k views

Practical application of matrices and determinants

I have learned recently about matrices and determinants and also about the geometrical interpretations, i.e, how the matrix is used for linear transformations and how determinants tell us about area/...
Vaishakh Sreekanth Menon's user avatar
1 vote
1 answer
71 views

Equations or areas where $(AA^T)^x$ or $(A^TA)^x$ are used as applications

Let $A$ be square or rectangular and $x\in \mathbb{R}$. Can you point me to equations/areas out there where $(AA^T)^x$ or $(A^TA)^x$ or their eigenvalues are used as applications? e.g. we find them in ...
Kay's user avatar
  • 571
2 votes
1 answer
110 views

Are there applications of equivalent matrices?

Similar to the definition here, matrices $A$, $B$ $\in \mathbb{C}^{m\times n}$ are said to be equivalent if there exist some invertible $m\times m$ matrix $P$ and some invertible $n\times n$ matrix $Q$...
Kay's user avatar
  • 571
4 votes
1 answer
385 views

What are practical examples of Toeplitz matrices?

A Toeplitz matrix is one in which each descending diagonal from left to right is constant. Given that structure, matrix operations are sometimes much faster. Where are Toeplitz matrices likely to ...
Brian Spiering's user avatar
1 vote
1 answer
59 views

Application of linear systems

A retired couple wishes to have an additional annual income of $\$6000$ per year. As their financial consultant, you recommend that they invest some money in Treasury Bills ($t$) that yield $6$%, ...
Melanie's user avatar
  • 467
5 votes
3 answers
3k views

Are there any applications of matrices, or linear algebra to chess? If so, are there good books on it?

Chess has never had any appeal to me, but recently my brother bought a chess set, and I realized that the board can be represented as an 8x8 matrix, and each type of of piece as a number from 0 to 6, ...
Daniel Bonilla Jaramillo's user avatar
8 votes
1 answer
480 views

Why do we care about normal matrices/operators?

We know that normal operators are "nice". In the finite dimensional case, the spectral theorem tells us everything we need to know. In the infinite dimensional case, we can define a continuous ...
Ben Grossmann's user avatar
1 vote
2 answers
848 views

Applications of non-square matrices

I am wondering if non-square matrices have many applications. It seems in my algebra classes we tend not to use them.
nobody's user avatar
  • 187
-1 votes
1 answer
75 views

An application of two 3x3 matrices identity [closed]

What is the proper context or the physical meaning for the following problem? In particular, is it related to a classical equation? Let $A$ and $B$ be two $3\times3$ matrices, such that $\det A=1$ ...
DVD's user avatar
  • 1,157
2 votes
1 answer
117 views

Applications where rank-1 matrices are useful

I am trying to list down applications where having a rank-1 matrix is advantageous. I know only of 2D convolution which boils down to a series of 1D convolutions if filter response is separable. Can ...
NAASI's user avatar
  • 997
1 vote
0 answers
32 views

The 1,1 coordinate of a Leslie matrix

I'm reading about Leslie matrices and I think I get the main idea. In the matrix, for instance, $$ \left( \begin{matrix} .2 & 1.1 & .5 \\ .9 & 0 & 0 \\ 0 & .7 & 0 \end{...
Addem's user avatar
  • 5,696
80 votes
4 answers
3k views

Factorial of a matrix: what could be the use of it?

Recently on this site, the question was raised how we might define the factorial operation $\mathsf{A}!$ on a square matrix $\mathsf{A}$. The answer, perhaps unsurprisingly, involves the Gamma ...
Oliphaunt's user avatar
  • 933
2 votes
0 answers
70 views

Matrix identification

Is there any name for a square, symmetric matrix, created in the following format: $$M_{i,j} = \left\{\begin{matrix} i + j & i \neq j\\ 0 & i = j \end{matrix}\right.$$ where $i, j$ start ...
Salvador Dali's user avatar
1 vote
1 answer
1k views

What are some Applications of Hermitian Positive Definite matrices?

I am learning about Hermitian positive definite matrices and the way that they can be decomposed with Cholesky decomposition. I have learned that these matrices deserve special attention for how often ...
Xoque55's user avatar
  • 4,429
-1 votes
2 answers
4k views

What are some real life applications of least squares problem?

I'm looking for some applications that require solving the least square problem. I know polynomial fitting is one of them, but sure there are many others. Thanks
AbcXYZ's user avatar
  • 440
69 votes
20 answers
9k views

What are some applications of elementary linear algebra outside of math?

I'm TAing linear algebra next quarter, and it strikes me that I only know one example of an application I can present to my students. I'm looking for applications of elementary linear algebra outside ...
0 votes
1 answer
298 views

Matrix diagonalization example

I want a real world example or simply a good example that explains the use of a diagonal matrix, and when to prefer to use a diagonal matrix? any other important information about diagonal matrix or ...
Michael Shenouda's user avatar
0 votes
0 answers
73 views

Representative value of non-square matrix

First of all, I apologise if this question is inappropriate, I wish I could be more specific - but due to the nature of it, as I am actually asking for a suggestion of some technique, that's hard to ...
OJFord's user avatar
  • 601
4 votes
3 answers
12k views

Real world situation with System of Equation with 3 variables?

Where do you run into a real world situation involving 3 variables and 3 equations? Can someone think of a specific example from business, etc? I recall taking an operations research course that ...
JackOfAll's user avatar
  • 4,771
7 votes
1 answer
5k views

A real life application for QR decomposition

I need to use the QR decomposition of a matrix for a real life application, (use it on a particular matrix form) and I have no idea what to do. Can you suggest me a real life application for this? ...
Mihai Alin's user avatar
2 votes
1 answer
3k views

Finding the "differentness" of two point clouds

I would like to reduce the "differentness" of two point clouds $X$ and $Y$ to a single comparable value $\lambda$, which would ideally be $0$ when $X$ and $Y$ are identical upto isometry (rotation, ...
Milosz's user avatar
  • 121
2 votes
3 answers
23k views

What are the applications of matrices in real world?

Matrices are considered very important in mathematics. What are some examples of applications of matrices to real world problems that would be understandable by a layman?
Shiva Saurabh's user avatar
4 votes
1 answer
1k views

Transpose a square matrix code

I know it's not programming area , but I think it's more related to math. I have the following function: ...
Billie's user avatar
  • 3,470
1 vote
1 answer
455 views

Represent a Toeplitz matrix in an array

I need to represent a $n \times n$ Toeplitz matrix in a $2n - 1$ array. I need to create a function that takes a pair $(i,j)$ and returns the value in the $2n - 1$ array. I am having a difficult time ...
Billie's user avatar
  • 3,470
4 votes
3 answers
1k views

Applications of companion matrices

I'm looking for interesting applications of companion matrices. I can also use the Frobenius Normal Form. I already covered the Cayley-Hamilton Theorem and the application to linearly recursive ...
justt's user avatar
  • 4,468
20 votes
2 answers
6k views

Ratio of largest eigenvalue to sum of eigenvalues -- where to read about it?

Let $E_j$ be the $j$th largest-magnitude eigenvalue of a real symmetric $N \times N$ matrix $M$. I've found that the ratio $$\frac{|E_1|}{\sum_{j=1}^N{|E_j|}},$$ is a measure of the "rank-one-ness" ...
Per's user avatar
  • 201
2 votes
1 answer
1k views

Find a price vector p for various prices of industries.

( Leontief input-output model ) Suppose that three industries are interrelated so that their outputs are used as inputs by themselves, according to the $3 \times 3$ consumption matrix A = [$a_{jk}$...
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