Questions tagged [matrix]
Questions on the manipulation of matrices in Mathematica.
2,408
questions
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Matrices of Machine- or Arbitrary-Precision Real Numbers Error While Using Arnoldi for Large Sparse Matrix
I'm trying to use the built in Arnoldi method in Mathematica to compute the first 1440 eigenvalues of a large sparse matrix. After importing
...
2
votes
3answers
44 views
Find minimum with matrix positive-definiteness constraint
Say I wish to find the minimum value of the determinant of a symmetric matrix under the condition that the matrix be positive definite. So I attempt:
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0
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0answers
53 views
Sum all the elements of a column
I have created the matrix m and I am not able to sum all the elements.
{1, 2, 3, 4} would give 10 for example.
Can anybody help?
Best,
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0answers
27 views
Errors in NDSolve for complex matrices
This is the problem. It is quite simple, and looks unwieldy only because I had to rewrite quaternions as complex matrices.
...
1
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0answers
44 views
$ x $ and $ y $ coordinates in ListLinePlot [closed]
I'm trying to make a ListLinePlot with my randomly generated data, and I want one vector to be the x coordinates of the graph, ...
5
votes
2answers
80 views
Apply Outer to list of matrices and vectors
I have a list, M, of square $ n \times n $ matrices, {M1, M2, M3, ...}, and a list, V, of $ ...
4
votes
2answers
178 views
Create a matrix from the rows of another, and calculate the rank of the new matrix
This may be a very basic question, so apologies in advance, I'm a first-time Mathematica & StackExchange user!
I have a 7x3 matrix X with all rows being unique in a 2D-list format.
For example:...
1
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0answers
63 views
How to use MatrixPlot as a DensityPlot?
I have a 1000x1000 matrix the MatrixPlot of which gives this graph:
The code is
...
1
vote
1answer
65 views
Cryptic NDSolve::nlnum when working with matrices
This problem was initially formulated in quaternions, but I had to rewrite them to complex matrices (as they seem to be supported better). Possibly introducing some errors along the way. So the ...
3
votes
1answer
79 views
Diagonalizing a symbolic matrix
I am trying to diagonalize the following matrix
\begin{equation}
\left(\begin{array}{cccc}
{ \frac{1-K\left(x_{2}^{2}+x_{3}^{2}\right)}{1-K|x|^{2}}} & { \frac{K x_{1} x_{2}}{1-K |x|^{2} }} & { ...
1
vote
1answer
39 views
The Matrix formula of this hamilton is different from that found in the paper
I am trying to rewrite the following Hamiltonian in the matrix form, but I get different results. In this article, the Hamiltonian that represents a three-qubit Heisenberg spin chain
and its matrix ...
1
vote
1answer
66 views
Efficient way to evaluate numerically product sines functions
I'm trying to perform integration of the following matrix.
...
2
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0answers
72 views
What's a quick test to see if an $n \times n$ matrix is diagonal and/or proporitional to the identity matrix? [closed]
As the title indicates, I want to test whether an $n \times n$ matrix (numeric, symbolic,..) is diagonal and/or proportional to the $n \times n$ identity matrix. I, of course, can test whether the $n^...
3
votes
1answer
58 views
Is this a correct implementation of the principal-leading-minors test for positive-semidefiniteness?
I am asking this question in response to comments by mikado and Daniel Lichtblau on my question Maximize a six-dimensional function subject to joint positive-semidefiniteness constraints
I gave two ...
0
votes
1answer
73 views
Maximize a six-dimensional function subject to joint positive-semidefiniteness constraints
I want to maximize
Abs[a1 b1] + Abs[a2 b2] + Abs[a3 b3]
subject to the joint constraints
...
2
votes
1answer
82 views
Building matrices of 0’s and 1’s
How would I go about computing the number of ways an nxn matrix of 1’s and 0’s can be made such that every nxm submatrix has more rows containing 1’s than the number of columns m?
2
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0answers
84 views
Converting complex equations to matrix form
My question is a continuation of the topic:
How to convert equation to vector (matrix) form?
It is necessary to separate the components of equations into vectors and matrices and a combination of ...
7
votes
3answers
299 views
How to eliminate rows and columns of matrices?
I would like to create an operation that checks if the elements of the row are 0 and eliminate the respective row and column associated with the row matrix. If if the lines have at least one non-zero ...
0
votes
1answer
47 views
How to update all values of a matrix with a multiple of their existing values
I have a matrix, and I want to multiply all the values in each element by Sqrt[2/3]. Here is the code.
...
6
votes
4answers
341 views
How to use genetic algorithm to calculate the maximum value of this matrix
1-9 the 9 numbers are arranged into 3 * 3 matrix without repetition.How to select the matrix with the largest determinant value:
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5
votes
2answers
143 views
Enumerating $4 \times 4$ matrices satisfying parity constraints
I've encountered a problem, which requires computer aid, but it seems a little above my Mathematica prowess because it requires counting objects satisfying some simple conditions. It seems doable, ...
1
vote
3answers
84 views
Create a new matrix from an existing matrix and then plot it
I have some code will test an equation and finds values for (n,j,k,l) in which the expression is true and puts them in the matrix - here is the code.
...
1
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0answers
22 views
Is there any relation between index of matirx AB and matrices A, B? [migrated]
index of matrix A is the smallest nonnegative integer k such that rank(Ak+1)=rank(Ak)
now i want to know which relation is between Index(AB) and Index(A), Index(B)?
1
vote
1answer
44 views
How to feed a list of disks to RegionUnion
I have a bit of code which creates a list of disks (I'm exploring Gershgorin circles) based on a matrix tm.
...
4
votes
1answer
483 views
Is this a bug or my mistake?
This:
Graph[{1 \[DirectedEdge] 2, 2 \[DirectedEdge] 3, 4 \[DirectedEdge] 1}]
AdjacencyMatrix[%] // MatrixForm
generates:
But, this
...
3
votes
2answers
96 views
How can I map edgeweights from a matrix onto edges along the paths generated by another matrix
Suppose that we have two matrices with identical dimensions: matA and matB. I want to identify a set of pathways using ...
2
votes
1answer
64 views
How to automize Shannon's Entropy calculation using a MM function
With the following code, I calculate Shannon's Entropy function HH1 for a given matrix mat. ...
3
votes
2answers
115 views
How do I make this Solve work faster?
I'm quite new to Mathematica and this code is taking forever to work.
Are there easy ways that will make this same code work much more quickly?
...
3
votes
2answers
74 views
Fixed point of a vector
It seems to me that FixedPoint is designed to work with a particular value, but what if we want it to operate on a vector instead?
I start with an nxn matrix mat and the function:
...
8
votes
3answers
356 views
How can I get all 4 × 4 submatrices of an n × n matrix?
I have a square matrix, I need to extract all possible combinations of 4 × 4 submatrices, where $n > 4$. For example in the case of a 6 × 6 matrix, there are 15 4 × 4 submatrices. I need the list ...
5
votes
2answers
344 views
How to reduce the λ-matrix to Smith Standard Form
A = {{1 - λ, 2 λ - 1, λ},
{λ, λ^2, -λ}, {1 + λ^2, λ^3 + λ - 1, -λ^2}}
How to reduce the above λ-matrix to the following Smith standard form:
...
1
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0answers
48 views
Find vectors describing two interconnected pyramids in Euclidean space
I need the help of competent linear algebra specialists in Mathematica.
In the Euclidean space, two tetrahedrons are turned at different angles. Their vertices coincide with the beginning of the base ...
1
vote
1answer
34 views
Exporting column vector as matrix in latex via “Copy as” doesn't always work. Example with vector
I want the simplest way of exporting matrices, and vector from mathematica to Latex.
Usually, I display my matrices in MatrixForm and copy as Latex to paste in my latex document. However it seems it ...
4
votes
3answers
128 views
Cell-adjacency Graph of a Square Mesh
Consider the list of points
pts = {{1, 1}, {1, 2}, {2, 1}, {2, 2}}
I want to use them to define a 2x2 square mesh using ...
1
vote
2answers
58 views
Keep important eigenvectors according to the important eigenvalues except one unimportant eigenvalue
I have an iteration whose steps extract a matrix with any possible dimension for example 3*3, 6*6, ...
4
votes
1answer
229 views
0
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2answers
75 views
2
votes
1answer
44 views
Inverse of matrix up to some order
Let $A(t,s)$ be a matrix of any size (potentially large), whose entries are polynomials functions wrt $(t,s)$ of order $N$.
I would like to compute the inverse $X$ of $A$ up to the order $N$ that is
$...
0
votes
1answer
30 views
How can I use a matrix element to plot with ParametricPlot? [closed]
This is a completely simplified example to demonstrate the issue.
I have a matrix, it contains an uninitialized variable. I need to extract that element of the matrix and use in to plot a parametric ...
2
votes
2answers
97 views
6
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4answers
356 views
How can I generate random matrices with certain requirements for the entries?
I would like to generate random 9x9 matrices, which contain only the digits 1-9, each one appearing exactly ...
1
vote
1answer
94 views
Solving the matrix quadratic equation: A.X.X + B.X + C == 0 analytically
I'm having difficulty figuring out how to solve a matrix quadratic of the form, $AXX + BX = -C$ analytically for $X$. Where $A$, $X$, $B$, and $C$ are $N \times N$ matrices.
I tried using ...
0
votes
2answers
103 views
How can I transform my calculation into a function?
I have written the following code, which serves my purpose. However, I like to have a Mathematica function such as
...
0
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0answers
38 views
Finding the Eigenvalues for big matrices
To start I have the following matrix (not so big)
I want to find the Eigenvalues in terms of kx and ky. I tried to use the classical
...
3
votes
3answers
239 views
How to join many tables side by side?
I have function for table $t$
t[n_] := Table[i*n, {i, 1, 3}];
For example t[1]=(1, 2, 3), t[2]=(2, 4, 6), and t[3]=(3, 6, 9)
To join $n=3$ tables side by side ...
1
vote
1answer
56 views
How to use Collect in Mathematica [closed]
For an input $n$, I have $n^2$ variables uu[1,1],...uu[1,n],...,[n,1],...,uu[n,n].
I have an equation that is linear in these (e.g. ...
1
vote
1answer
57 views
How to “undo” an outer product
I have a matrix which is formed from the outer product of two complex vectors. There is some noise as well. How can I get the best estimate of the complex vector?
Here is a case without noise for a ...
3
votes
2answers
100 views
Print command in matrices to generate inactive numbers
I would like to generate a matrix with elements that come from a print command and are numbers and then multiply the first matrix by another one, element by element.
However, I would like the ...
4
votes
3answers
429 views
Generating all 2x2 matrices with entries from 0 to 3 whose det is 1 with mod 2 arithmetic
I am trying to make a list of 2x2 matrices whose entries are all possible permutations of 0,1,2 and det=1 mod 2 arithmetic.
First I tried to create a Table like this
...
0
votes
1answer
33 views
How to make a tensor product into matrix?
TensorProduct[PauliMatrix[1], DiagonalMatrix[{1, 1}]] // TableForm
created a tensor, which could be flatten to table form.
However, how to make the tensor into a ...
