Questions tagged [matrix]

Questions on the manipulation of matrices in Mathematica.

2,307 questions
Filter by
Sorted by
Tagged with
49 views

Print 4x4x4x4 tensor as 4x4 matrix of 4x4 matrices [closed]

I'd like to print the LeviCivitaTensor tensor as 4x4 block matrix of 4x4 matrices The following code works to display the LeviCivitaTensor tensor as a 3x1 vector of 3x3 matrices. ...
63 views

How to import a part of an Excel file?

I'm trying to import a part of an excel, the column 20 and the row between 6-59 in this column. I tried : tab = Import[ "file.xlsx"]; time = tab[[20, 6 ;; 59]] ...
76 views

How to get eigenvectors of a 4x4 matrix? [closed]

MatrixForm[m = {{2, 9, 0}, {3, 8, 9}, {3, 9, 1}}] Eigensystem[m] I am facing problem in finding eigenvectors using ...
533 views

Optimising subdiagonal shift matrix generation time

I want a square matrix $A$ such that $$A_{i,i-1} = 1 \ \forall i\\ A_{i,j} = 0 \text{ for } \ j \ne i-1$$ I have tried ...
39 views

NSolve cannot find solution to system of trig equations

I was making a program to convert a rotation matrix to a set of euler angles. I wanted to do this for any valid rotation order that the euler angles were made with, and I did not want to do it the ...
159 views

Generate random non-zero “island” in matrix of zeros

I'm trying to write a code which will generate a 3 dimensional array of 0s, then pick some random location in the array, and subsequently expand contiguously to random neighboring sites until a set of ...
43 views

Mathematica doesn't evaluate/simplify arithmetic expression in its output [closed]

I have two matrices, A := {{1, 2, -4}, {2, -2, -2}, {-4, -2, 1}} and ...
18 views

Solve, store, and access eigenvalues and eigenstates of M[x,y], for various points {x,y}

I'm interested in solving a position dependent eigenvalue problem for matrix M[x,y], where {x,y} is some discretized set of points. I may need to access the eigenstates and eigenvalues multiple times ...
43 views

How to export a multidimensional array in which each element is also an array?

I have a {15,5,2} dimensional array and each element is itself a {14,16} dimensional array. When I export/import my file as an excel file I get a {15,,5,2} dimensional array but with {} dimension for ...
34 views

Bug in SmithDecomposition?

While trying to calculate the SmithDecomposition of an integer 293x329 matrix with less than 3000 non-zero elements in the range -4 to 3 several errors occur, none of them which seem to make any sense ...
45 views

How can I arrange the columns of a transposed matrix in an special way?

How can I do the below process on a matrix in a straightforward way: Firstly, change the rows with columns and secondly, arrange the columns of the matrix in a way that for a N*N matrix, the first ...
41 views

I am asserting a variable in Mathematica as Real yet it is not implementing it!

Element[\[Theta], Reals]; Ga = g; Gb = g*Exp[I*\[Theta]]; {{Conjugate[Gb], Ga}, {Ga, Gb}} I have a code as such for a matrix as given above. as ...
53 views

Time used by Mathematica to calculate tridiagonal matrix

I have a question. I need to find the eigenvalues and eigenvectors of a tridiagonal matrix of size NxN. Can you tell me how much time does Mathematica need to do that in minutes? for Size N ...
40 views

How to assemble matrices (updated)?

I wish to update my question. Based off the answer provided, I tried ArrayFlatten for the following: 𝐴 is a 4x2 matrix, 𝐵 is a 4x4 matrix, and 𝐶 is a 4x6 matrix. I tried this to construct a 4x12 ...
53 views

80 views

46 views

Simplifying an expression involving a matrix and functions of it

I have implemented the following two matrices in Mathematica in order to compute s, but I don't know how I can further simplify the resulting expressions, e.g., ...
29 views

Verify that a PDE is satisfied by a matrix consisting of functions satisfying a different PDE

My problem is as follows: I have two matrices $P$ and $Q$ which are made up of algebraic expressions of a function $q(x,t)$ which solves a somewhat complicated pde, and its derivatives, for example, ...
59 views

How do I create a Jacobian matrix for a large system of equations?

I would like to create a Jacobian matrix using the simplified functions below: f1[a_,b_,c_]:= a^2 + b^2 f2[a_,b_,c_]:= c/2 f3[a_,b_,c_]:= b^3 I say simplified ...
55 views

Matrix whose coefficients are functions

What is the right way to declare of matrix whose coefficients are functions of a variable $x$ ? I tried : Table[Table[a[i,j][x_],{j,1,NN}],{i,1,NN}]
347 views

How to denote matrix elements succinctly? [closed]

Is there a more elegant way of dealing with the following subscripting? ...
36 views

Show result of matrix operation in terms of user defined matrices

I have defined some matrices K,K,...,K and S,...