Questions tagged [matrix]
Questions on the manipulation of matrices in Mathematica.
3
votes
2answers
67 views
Working Iterative formula for a system of equations
I have been given a project, I need to show the use of a version of Newton's method to solve these non-linear equations. The version of Newton's method I am required to use is: $ X_{n+1} = X_n - J^{(-...
2
votes
0answers
45 views
How can I perform the modified Cholesky factorization/Decomposition in Mathematica?
How to "Modified" Cholesky Decomposition in Mathematica?
what I mean:
V = L . D . Transpose[L]
V is p*p(row is p,columns is p) non-negative definite matrix,
D is diag[$d\small1$,$d\small2$,$d\...
1
vote
1answer
106 views
Solving the eigenvalue problem for a double well potential using a 1D particle in a box as a basis set
My first question is how would I go about getting the 1D particle in a box eigenfunctions using matrix techniques and how would I use the particle in a box eigenfunctions as a basis set for the ...
1
vote
1answer
29 views
Hessian matrix product in Taylor expansion of vector function
I am trying to get the 2nd order coefficient of the Taylor expansion at $\pmb{x}=\pmb{0}$ of
...
1
vote
1answer
46 views
Partial trace and Partial Transposition of a matrix easily?
Could someone help me to understand as to how to compute the partial trace and partial-transposition of an arbitrary matrix? I mean, is there any code to carry out these operations in Mathematica?
...
3
votes
3answers
68 views
Replacing a column of a matrix
I want to replace a column of a matrix. The best I've been able to come up with is
...
0
votes
1answer
110 views
Constructing a matrix from different blocks
Suppose I have a symbolic matrix called MAIN as follows
$$
\begin{matrix}
H_{00} & H_{01} & \ldots & H_{0n}\\
H_{10} & H_{11}& \ldots & H_{1n}\\
\vdots & \vdots & \...
0
votes
0answers
37 views
0
votes
0answers
11 views
How to transform a real matrix with complex eigenvalues into a positive definite real matrix?
If the matrix had real eigenvalues, I would substitute the negative eigenvalues by a small positive number. However, I have complex eigenvalues...
How should I proceed to transform the original ...
1
vote
0answers
27 views
Dimension of Grid in CUDAFunctionLoad for Matrix Multiplication
I want to do nonsquare matrix multiplication using CUDA
The input is two matrices: a and b
...
3
votes
2answers
146 views
How to drop certain elements in certain positions from a list using drop function
a = Table[i, {i, 1, 10}]
Drop[a, {5, 8}]
If go with the above procedure, It will delete all the elements from between position 5 to 8. How to drop elements which ...
0
votes
0answers
31 views
Find a matrix that are unitarily equal to the given matrix
I have four $5\times 5$ matrices, $P_i, Q_i$ ($i=1, 2$) as follows:
$P_1=\begin{pmatrix}
1 & 0 & 0 & 0 & 0 \\
0 & 1 & 0 & 0 & 0 \\
0 & 0 & 0 & 0 & -...
1
vote
2answers
67 views
Max in every row and column in bimatrix game
I want to find the maximum value in each column by comparing only the first elements (-8 and 10) and (0 and -1) and maximum value in each row by comparing only the second elements {-8 and -10) and (0 ...
0
votes
1answer
17 views
How can I specify the region for every variable simultaneously in NMinimize?
I want to use NMinimize to find the unknown unitary matrix that solves a (possibly nonlinear) matrix equation. For example, the one that transforms the Pauli matrix ...
1
vote
1answer
28 views
Find a matrix $X$ that block-diagonalizes a particular group of matrices
Essentially, I want to find a single matrix $X$ such that conjugation by $X$ sends:
$$\begin{bmatrix}
1 & 0 & 0 & 0 & 0 \\
0 & -1 & 0 & 0 & 0 \\
0 & 0 & 1 &...
4
votes
2answers
84 views
OpenCL compute large matrices
I am trying to compute a big matrix $C$, of size $M \times N$, using the elements of the input matrices $A$ and $B$. The matrix $A$ is of size $M\times4$ and the matrix $B$ is of the size $2\times N$. ...
1
vote
1answer
139 views
While loop (or alternative) to generate list of random submatrices satisfying condition
I'm trying to generate a list of random submatrices with matrix norm 0.1, however I'm getting stuck; currently my code looks like this, where I run over a while loop.
...
4
votes
1answer
50 views
Populate matrix from linear system
What is the strategy to populate a matrix from a linear system of equations?
As a toy example, I have some scary, complicated math, that generates eq1 and ...
0
votes
0answers
56 views
How to obtain left and right eigenvectors of a general complex matrix with degenerate eigenvalues?
I'm looking to obtain the left and right eigenvectors of a general complex matrix. The left eigenvectors satisfy the equation: $\phi^L_i L = \lambda_i \phi^L_i$, with $\lambda_i$ being the $i$th ...
0
votes
3answers
26 views
Low precision from function returning matrix
Got a function depending on single parameter "t" defined below which
returns a 2 by 2 matrix
...
1
vote
1answer
72 views
How to import complex .txt file to matrix in MMA for user defined keywords / database?
I am thinking about how can we import complex .txt file (Ansys/Abaqus) to MMA for the selected database?
For example: txt file (input file):
...
1
vote
1answer
56 views
Derivative with respect to any element of a matrix
I try to evaluate
$$ \frac{\partial s}{\partial A_{ab}} $$
where
$$ s = \sum_{i} \sum_{j} A_{ij}$$
The result should be 1 regardless of $a$ and $b$. But the following code gives zero.
...
2
votes
2answers
33 views
Using ReplaceAll on matrix to produce new list of complete matrices
This seems like something simple but I can't find the answer.
If I have as input:
{{1, 2}, {3, d}} /. d -> {4, -4}
Mathematica outputs:
...
2
votes
0answers
47 views
How to construct a time-dependent matrix quickly?
In the process of discretization of a 4D PDE, I need to construct a final sparse matrix $B$, which is very large (I denoted by $\text{size}$ here) and time-dependent, viz, some of its entries change ...
0
votes
1answer
65 views
Finding all the solutions of some matrix equations
I am trying to find all possible solutions to the following:
A = ( {
{a11, a12},
{a21, a22}
} );
B = ( {
{b11, b12},
{b21, b22}
} );
A.A
<...
1
vote
1answer
37 views
Finding a fundamental system of solutions of the homogeneous system [closed]
Hey guys im having problems with as the title says finding a fundamental system of solutions of the homogeneous system Vx = o
Based on :
Matrix
...
3
votes
1answer
49 views
Solving $\det{(A+\epsilon B)}=0$ for large, symmetric and dense $A$ and $B$
In an algorithm I am writing, I need to solve the equation
$$ \det{(A+\epsilon B)} = 0, $$
for the smallest value of $\epsilon$, given large ($n$x$n$ ideally up to 150x150), dense and symmetric A ...
3
votes
4answers
154 views
Fast way to create $[ I_4\otimes e_1,\ \dots ,\ I_4 \otimes e_T]$?
Is there a fast way to construct this matrix?
$\left[\begin{array}{c}
I_4\otimes e_1\\
\vdots \\
I_4 \otimes e_T \end{array}\right]$
$e_i$ is the $i$-th column of the matrix $I_T$, $\otimes$ is the ...
2
votes
1answer
53 views
Inaccurate zero eigenvalues for 7*7 matrix [closed]
I have symbolic entries for all the elements of a 7*7 matrix. At the symbolic level Eigenvalues gives two zeroes and five others that are extremely complicated. At ...
5
votes
2answers
83 views
Plot values of matrixplot as well as the matrixplot itself inside Manipulate [duplicate]
Given a MatrixPlot inside a Manipulate, say some $M(t)$ where $M_{ij}$ real for all entries, is there a way to show the values ...
5
votes
3answers
100 views
Better code for reversing and joining matrices
I am writing a function to reverse a matrix and join the reversed version to the original one, making a new matrix which I call A. And after doing this, I reverse <...
2
votes
2answers
38 views
determining the coefficient matrix
We have a set of equations as
a x + b y = c z + d w
e x + f y = g z + h w
We wish to have a matrix as below :
How can we reach the ...
0
votes
0answers
35 views
Solving a system of linear equations in Mathematica regarding the errors of different methods
I have a system of equations, i.e.
0.62243x + 0.51824y = 0.70524
0.71497x + 0.59496y = 0.80996
I have 3 ways to solve this system (there are more but I am ...
0
votes
1answer
81 views
Max in every column and Min in every row
I have a matrix such as this
mat ={{6, 5},{5, 4}}
and I want to find the maximum in every column and minimum in every row. After that I have to get the same ...
0
votes
1answer
25 views
Eliminate the higher powers of eigenvalues of a matrix
I want to found de eigenvalue of following matrix
...
0
votes
0answers
19 views
Method option of function MatrixRank
By running ??MatrixRank, I see that it has an optional argument named Method.
However, this argument is not in the ...
8
votes
1answer
420 views
Is there a faster way to vectorize a matrix than this?
I want to put all the columns stacked up, as a vector.
The fastest code I could come up with was
Transpose[{Flatten[Transpose[A]]}]
Is there a faster way?
0
votes
0answers
73 views
Constructing a block diagonal matrix
I have a problem in transforming a matrix into a block diagonal matrix.
My matrix has the form:
Mat=
\begin{array}{cccc}
a & b & c & 0 \\
b & 0 & 0 & c \\
c & 0 & ...
2
votes
2answers
235 views
How do I write this matrix?
The following code gives 20 data as output.
How can I make a 5*4 matrix by that data list?
3
votes
2answers
89 views
Programming with Mathematica Syntax - Dunford decomposition
I am always amazed while I am reading some solutions of problems in mathematical problems of this site with Mathematica.
For instance, look at the problem 48.
Whereas I am writing 100 lines of code ...
1
vote
2answers
43 views
Integrate over matrix elements
I wish to perform the integral
$$
\int \prod_{i,j}dM_{ij}\exp\left(-Tr(M^2)\right)
$$
where we integrate over the matrix elements of $M$. I tried
...
2
votes
2answers
51 views
How to write a matrix of $n\times 2$ where the first column is made of only 1's?
How to write a matrix of $n\times 2$ where the first column is made of only 1's?
Suppose I have a vector x={.24,...,10}.
How can I get this
$\left(
\begin{matrix}
1 & .24 \\
1 & ...
0
votes
0answers
18 views
Matrix multiplication Q.W not working - Result=matrix Q . matrix W [duplicate]
When I write the code to do the dot product between two matrices, Mathematica does not compute it:
How can I get the right matrix?
EDIT
Thank you for your willingness.
1
vote
2answers
54 views
How can I construct a matrix by programming in mathematica?
I want to write a matrix in Mathematica by programming. How can I write it?
The matrix is :
$
M=
\begin{bmatrix}
0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & ...
7
votes
3answers
373 views
1
vote
2answers
34 views
Build matrix from smaller matrices or rearange list of lists
Start with the fact that I am a new user of Mathematica, and this is my problem:
I have a complex simbolic matrix A (rectangular, 14x14), and I want to build a matrix from its imagenary and real ...
0
votes
1answer
99 views
setting up a variable matrix
I am trying to set up a variable matrix, where I have a variable x that goes from 0 to 2 and a variable z that goes from 0 to 2. I have two other variables m and n that depend on both x and z. How ...
1
vote
3answers
93 views
Find k largest edges with unique nodes (kind of maximum weighted matching)
I have a weighted graph, and I am interested to find k largest edges with unique nodes.
Currently, I do it in the following manner
...
3
votes
2answers
123 views
Problem about Inner product of matrix with two vectors
If A, B are two lists with length n and M is a n*n Matrices, then I want to compute the inner product of them ...
1
vote
0answers
65 views
Summation over gamma matrices in a spin connection with FeynCalc
I need to construct the following object
$\Gamma_{\mu} = \frac{1}{8} \omega_{\mu}^{ab}[\gamma_{a},\gamma_{b}]$
where $\omega_{\mu}^{ab}$ is object with space-time index $\mu$ and vierbeins index $a, ...
