Questions tagged [matrix]
Questions on the manipulation of matrices in Mathematica.
2,994
questions
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Lanczos method to tridagonalize a matrix
I want to tridagonalize a sparse matrix using the Lanczos algorithm.
I am working with a very large sparse matrix and I need some speed. In the following for example ...
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0answers
17 views
2
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0answers
53 views
Typing the value of matrix elements in matrix plot [duplicate]
I want to type the value of matrix elements when plotting it on the topside of the bar.
Example:
$$M=\left(\begin{matrix}
0.77 & 0.04 & 0.01 & 0.0\\
0.04 & 0.81 & 0.0 & 0.0\\
0....
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0answers
51 views
matrix problem: evaluation of column values which depend on a variable
I do not use Mathematica for a long time and I have a question about a matrix problem.
I add here the code:
...
1
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0answers
76 views
Null Christoffel symbols associated to the FLRW metric obtained via Mathematica [closed]
I'm trying to make a mathematica notebook that computes the Christoffel symbols associated to the Friedmann-Lemaître-Robertson-Walker metric (noted FLRW in the notebook) describing an homogenous and ...
0
votes
0answers
52 views
How to find the eigenvalues of a matrix [closed]
I'm new to mathematica so don't have alot of experience with it. I'm currently trying to make code to find the eigenvalues of this matrix but keep getting an incorrect answer - could someone let me ...
1
vote
1answer
63 views
Concatenating matrices using headings
New to Mathematica. I want to create and combine K1, K2, and K3 (shown in the first picture below) into the 8x8 matrix shown in the second picture below and keep the heading as shown if possible:
...
5
votes
1answer
136 views
Conditional sorting of columns in a matrix
I have a matrix with ten columns, and I want to rearrange these columns with three conditions.
Column 1+2n and 2+2n (0<=n=<4) always remain together and in the same order (1+2n before 2+2n). ...
1
vote
1answer
69 views
How do i create a function which returns a table/matrix in mathematica?
I'm trying to create a matrix which will be of size 2N by 2N and have entries which will depend on the column and row number (u and v here). I'm sure this is a very trivial question but i'm really ...
3
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5answers
163 views
how to add rows to a matrix to achieve a given order
I have a large number of matrices having equal numbers of columns but different numbers of rows. Say, their order is n X 4, Where n can be any integer between 1000 to 1050. How to tell Mathematica to ...
2
votes
0answers
70 views
Extract the dynamical map from the density matrix
I am working on open quantum systems and have been wondering whether there is a way to extract the dynamical map using mathematica. Say we have a density matrix
$\rho(t) = \begin{bmatrix} p_{00} + (1 -...
2
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0answers
72 views
dot product of one thousand matrices [closed]
I have a time dependent matrix. In a thousand different times with the same time intervals I get the values of the matrices. Now, how can I DOT Product these thousand matrices in time order??
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43 views
Block Matrix Algebra of Implicit Matricies
I get some unexpected behaviour from building block matrices of implicit matrices in Mathematica. Using this initial setup
...
2
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0answers
75 views
Building a Matrix as a piecewise-function of the indices without for loops [closed]
I'm very new to Mathematica and this site. I've read that building matrices with For loops is slow, and I have experienced this myself on the current project. I'm trying to wrap my head around ...
1
vote
1answer
67 views
Matrix differential equation with DSolve doesn't work
I'm trying to solve matrix differential equation with DSolve, but I got an error.
...
0
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2answers
80 views
How to find a matrix satisfying following equation
I have a $N \times 1$ vector $F(t)$ for $0\leq t \leq 1$.
I want to find a $N\times N$ Matrix $C$ (a real-valued matrix) satisfying the following equation:
$$\int_0^t F(t_0)dt_0= C.F(t)$$
If it ...
0
votes
2answers
53 views
Can I save data as a three-column matrix?
I need to store values of a function of x and y defined as f[x_, y_] := Sin[Pi*x/3]*Sin[Pi*y/3] at the following points ...
1
vote
1answer
45 views
How do I make Mathematica to always evaluate Log[0, x] as Power[0, x]?
So, sometimes Mathematica cannot evaluate the base-0 logarithm of certain matrices.
But we know that the expressions $0^x$ and $\log_0 x$ are always equivalent.
What can I do so that Mathematica ...
0
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1answer
61 views
How do I improve this code for hyperbolic numbers so to allow equation-solving?
I have the following code, which allows evaluating expressions with split-complex unity J:
...
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0answers
51 views
Selecting a matrix element with [[ ]] doesn't work [duplicate]
I am trying to select a matrix element using Part or [[ ]] but somehow it doesn't work.
...
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1answer
41 views
0
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1answer
54 views
Basics for recursive functions [duplicate]
I am new to Mathematica and try to define a simple recursive formula which is illustrated as below:
...
2
votes
1answer
100 views
How to find a transformation matrix between two set of operators?
The following set of operators $P_1,P_2,P_3,P_4$ and $Q_1,Q_2,Q_3,Q_4$ are related as $P_i=\sum_j w_{ij} Q_j$. How can I find the matrix $W=[w_{ij}]$?
...
1
vote
1answer
71 views
Can we show that two matrices are unitarily equivalent?
Is it possible to show that matrix a1 defined as
...
1
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1answer
48 views
Matrix multiplication with non-commuting objects (Quantum)
Given a matrix A = {{0,a,a,0},{b,0,0,a},{b,0,0,a},{0,b,b,0}}, where $a$ and $b$ do not commute, how do I calculate $A^2$ in Mathematica?
(Later on, I would like to ...
1
vote
1answer
36 views
Phenomena between ill-conditioned and well-condtioned
Given that I have the following sparse matrix:
...
0
votes
2answers
71 views
How can I multiply two 2-dim. matrices? [closed]
If I have the given below matrix d1[7,7], how can I multiply d1 by d1 to get the square matrix d2=d1.d1 ?
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1
vote
1answer
44 views
How can I get matrices and text to show up in the same table with MatrixForm?
I'd like to be able to display matrices in the usual written MatrixForm in a table alongside text (or anything that isn't a matrix). Here is an example:
...
3
votes
1answer
51 views
Converting Association to Matrix
Imagine I have the following association, where the keys are given as pairs of natural numbers
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1
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1answer
77 views
Matlab code to Mathemtica, Tensor
I am trying to convert a Matlab code to Mathematica.
I have a tensor, RF (a,b,c,d) which is constructed from Hamiltonian (Hs) and 2x2 identity matrix (DS):
...
1
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0answers
23 views
'Tag in is protected' error in eigenvaules for large size Hamiltonian [closed]
I am trying to compute the eigenvalues for any size Hamiltonian matrix. To do this, I first manually compute the first few cases for N=2,3. However, when I want to see what happens for N=4, I meet ...
2
votes
1answer
70 views
How to Write a matrix Laurent polynomial $A_{-5}t^{-5} + A_{-4}t^{-4} + ...+ A_0 + A_1 t + A_2 t^2....$ in mathematica [closed]
I need to write in mathematica programming language a matrix Laurent Polynomial
$$ T = \sum_{i=-5}^{5} A_i t ^i $$
where the $A_i$ are $n \times n$ matrices (I want the entries to be symbolic) which ...
1
vote
0answers
52 views
How can I extract a sub matrix of order 4*4 from four 2*2 corner blocks of a 6*6 matrix? [closed]
Let
mat = RandomInteger[10, {6, 6}];
mat // MatrixForm
I can access elements as follows
...
0
votes
2answers
81 views
0
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1answer
63 views
Construct a matrix from its elements and solve the eigenvalue problem
I want to construct a 10 by 10 matrix whose elements are given by
$$
H_{nm}=\delta_{nm}\left (n^2+v[b_1-b_0-h(2m,b_0,b_1)]\right) \\ +v(1-\delta_{nm})\left (h(n-m,b_0,b_1)-h(n+m,b_0,b_1)\right)
$$
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0answers
42 views
Equation issue: Solve gives an empty output
I need c1,c2....c9 values. Why is Solve returning an empty list?
How i can fix it? Thanks for any advice.
...
0
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0answers
31 views
Matrix modification with constraint on it
$q$ is a real antisymmetric matrix and can be defined as:
...
0
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1answer
73 views
Problem with the plots of eigenvalues of the Matrix
I am trying to plot the eigenvalues of the following matrix
...
3
votes
2answers
103 views
Creating a matrix of dimension d with constraints on indices
Is there a way to create a matrix $q$ of dimension $d$ with constraints on the indices given by:
$$d\longrightarrow dimension$$
$i,j $ are indices
$$q_{i,j}=\begin{cases}
-b & j=i+d,\\
c & j=...
3
votes
1answer
78 views
Implementing empty matrix?
Matlab is famous for having implementation of empty matrices. The Matlab tutorial says "As
far as we know, the literature on the algebra of empty matrices is itself empty. We’re not
sure we’ve ...
2
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0answers
40 views
JordanDecomposition not evaluating
When there are very small differences between entries in a diagonal matrix, sometimes JordanDecomposition does not evaluate and gives an error message:
...
3
votes
1answer
71 views
Performing matrix tensor product and getting a sum of its negative entries
I am given a $3 \times 3$ matrix $M$, which only has real entries.
Is there an efficient way to do the following two operations with $M$?
For a given input $n$, compute the $n$-fold tensor product $M^...
0
votes
1answer
72 views
sum of symmetric matrix is not symmetric
Within the development of a Markov Chain Montecarlo algorithm, I need to do the Cholesky decomposition of a matrix. The matrix is the sum of two matrices m1=Transpose[a].a and m2=Transpose[b].b; A ...
0
votes
2answers
43 views
Data wrangling to create a matrix from lists
I have a super simple data wrangling question that I can't seem to figure out (I am new to Mathematica). Basically I'm not sure what function to use. I have two parameters, ...
2
votes
1answer
29 views
3
votes
1answer
129 views
How to implement Drazin inverse?
Wolfram site says it will be implemented in the future as DrazinInverse[m] function. But what to do now?
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0answers
31 views
Trajectory Design Matrix
I've been tasked with creating a small demonstration for educational purposes of the Morris Screening Method but am having trouble implementing the trajectory design matrix in Mathematica. It's a ...
1
vote
2answers
100 views
Taking a diagonal cut through a matrix
Lets say I have a gaussian data matrix, e.g.
x=GaussianMatrix[20]
I would like to take a cut through this matrix at a 45 degree angle to get its intensity profile, ...
1
vote
0answers
63 views
How do I carry out a partial row reduction of a matrix? [closed]
I have a large matrix with more columns than rows. I have attempted to row reduce the matrix using Mathematica's RowReduce command. I have been able to do this ...
2
votes
1answer
52 views
