Questions on the manipulation of matrices in Mathematica.

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3
votes
3answers
95 views

Creating a matrix under conditions

I would like to create a matrix whose elements satisfy the following conditions ( Mathematica 9 ) ...
-3
votes
0answers
29 views

Get function creating variables inside [on hold]

I want to use Mathematica to create this function in pseudocode: ...
0
votes
0answers
34 views

Topics for master's project using Mathematica [on hold]

I wish to do 1 year project in linear algebra using Mathematica. What are linear algebra topics which can be implemented on Mathematica as part of 1 year graduate level dissertation.
2
votes
1answer
84 views

Proving positive definiteness or semi-definiteness of a matrix

I have the following 4x4 real symmetric matrix: $K=\begin{bmatrix}3-3w & -\frac{4}{3}+a+2w & \frac{5}{12}+b-\frac{w}{2} & 0\\ -\frac{4}{3}+a+2w & -1-6a-3x & ...
0
votes
2answers
34 views

in the part assignment is not a symbol, create different matrices with a loop

Im trying to assemble new matrices from some previous matrices I have created, but I can´t. What Im trying to do is the following: 1) I have different matrices: ...
2
votes
1answer
144 views

Is there a bug in MatrixExp in Mathematica v10?

I'm trying to compute MatrixExp[-I t {{0, 1/2, 0, 0, 1/2}, {1/2, 0, 1/2, 0, 0}, {0, 1/2, 0, 1/2, 0}, {0, 0, 1/2, 0, 1/2}, {1/2, 0, 0, 1/2, 0}}] With ver 9 the ...
0
votes
1answer
30 views

Getting nicer values for eigensystems [closed]

I want to find the eigensystem of the matrix {{0.9, 0.5}, {0.1, 0.5}}. I tried Eigensystem[{{0.9, 0.5}, {0.1, 0.5}}] The ...
0
votes
2answers
70 views

Block anti-diagonalize a square matrix?

In Mathematica there is a very convenient function called JordanDecomposition[]. It takes a square matrix A as an argument and ...
0
votes
1answer
49 views

How to get rid of # in answer (eigensystem)? [duplicate]

I was trying to find the eigensystem of the following matrix (act as if the second character is in subscript): \begin{pmatrix} 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \\ ...
0
votes
0answers
26 views

How to tweak a symbolic RowReduce?

B = {{-1, 1, 0, a}, {-1, 1, 0, a}, {-1, 1, 0, b}}; MatrixForm[B] RowReduce[B] // MatrixForm Mathematica is indeed giving ...
0
votes
1answer
35 views

Finite Field matrix rank calculation

How does one define a matrix over $GF(p^r)$ in mathematica in order to compute rank? I am working with $GF(2)$?
1
vote
1answer
58 views

Optimizing matrix inequalities over trace

I need to solve the following problem. Given $n \times n$ Hermitian matrices $A\geq 0$ and $B_1, ~ B_2$ (need not be positive semidefinite), with $Tr(AB_1)<0~,Tr(AB_2)<0$ construct a ...
4
votes
3answers
252 views

Complex conjugate

How do I complex conjugate a vector? ...
0
votes
1answer
82 views

What if do NOT want Mathematica to normalize eigenvectors with Eigenvectors[N[matrix]]?

ORIGINAL QUESTION Question speaks for itself. Mathematica normalizes the eigenvectors automatically when you type Eigenvectors[N[matrix]]. What if I do NOT want ...
2
votes
1answer
51 views

Inverting matrix with assumptions

I want to invert a matrix that contains some variables, so I thought I should give some assumptions to Mathematica to speed up the process. How do I assume that $s0,...,s8$ are positive constants ...
0
votes
0answers
31 views

A problem about NIntegrate the smaller eigenvalue for a matrix

Define a matrix and a function as ...
1
vote
1answer
90 views

Why can't Mathematica compute the null space of these matrices?

I'm writing a library of functions to work with musical pitch-class vectors. One of my functions gives me a skew-symmetric matrix modulo 12 that corresponds to the differences between components of ...
0
votes
2answers
78 views

Calculating eigenvalues of a large matrix takes a long time

I have a tridiagonal matrix (1000×1000) with each element equal to "one" except {n,n}=2`. It takes 8 hours to give me the eigenvalues?!!. Here, the code I used: ...
1
vote
2answers
150 views

Manipulating elements of a matrix, to loop or not ?

I have a grid of values generated from a MATLAB evaluation. Most of these elements are 0, some 0.5 and the remainder 1. I'd like to write a mathematica script which reads in the CSV and then, in every ...
0
votes
2answers
70 views

Matrix operation (simplify)

I had a $6\times 6$ matrix ...
2
votes
1answer
71 views

Stochastic Predator-Prey model using Gillespie's SSA

I'm trying to model the predator-prey situation using SSA. I am very new to Mathematica so my handling of matrices is probably terrible, and that's probably adding to my confusion: ...
0
votes
1answer
30 views

Assigning some results after a solve procedure to the coefficients of a matrix

I have a matrix M[3,3]. After a solve procedure, I obtained these results. {{M[1, 2] -> Cos[ψ[t]], M[1, 3] -> 0, M[2, 3] -> 0, Cos[θ[t]] -> M[3, 1], M[3, 2] -> 0, M[3, 3] -> 1, M[2, 1] -> ...
0
votes
0answers
47 views

Calculating the rank of an abstract matrix

I'm trying to compute the rank of a 4x4 matrix with 4 parameters and 2 variables. I tried to calculate its rank under some assumptions on those conditions and I kept getting rank 4. So I did an ...
0
votes
2answers
46 views

Nonlinear matrix equation solving in Mathematica

is it possible to solve below equation in Mathematica? A.X+B.Exp[X]==C A, B are square ...
0
votes
0answers
59 views

Calculate the matrix M such M.X=omega

I would like to determine the matrix M[3,3] such as M.X=w. ...
2
votes
0answers
247 views

How to invert a matrix with 100 trillion elements?

I have a $10^{7}\times 10^{7}$ matrix with the following properties: it is sparse it is gamma-5 it is almost Hermitian. If $M$ is the matrix we are trying to invert, we know $M=A M^{\dagger} A$ ...
6
votes
3answers
214 views

How to build a matrix from a set of vectors and other matrices using ArrayFlatten

I want to build a 6 by 3 matrix, from the following: one vector is 3 by 1, then a matrix, which is 3 by 2. These will go to the top 3 rows. Now the bottom 3 rows, I'll have 3 vectors each is 3 by 1. ...
1
vote
2answers
93 views

Solving matrix equation

How can I solve the forward equation S[t]=C+A*S[t+1]*(Inverse((I-B*S(t+1)))*A for t=1 to t=10 and ...
1
vote
0answers
63 views

Find algorithm or generator formula with automated procedure and pattern recognition

I am trying to find a generator formula for the discriminant of a polynomial and believe it would be an interesting problem for the Mathematica community to know how to automate evaluation of certain ...
2
votes
2answers
97 views

Diagonal minors of matrix

I need to calculate the minor of a matrix. I am going to use Mathematica example here, ...
3
votes
3answers
120 views

List manipulation: Dropping first or last row or column of a matrix

How do I drop the first/last row or first/last column from a matrix? The general case is answered here but I am new to Mathematica and it the arbitrary case is unnecessarily complex. Suppose I am ...
0
votes
1answer
36 views

Elements inside arrays seem to be strings rather than signed numbers

When I have code like b = Array[Subscript[be, #] &, {3, 1}] b = b /. {Subscript[be, k_] :> Subscript[-be, k] /; k > 1} I am noticing that Mathematica ...
4
votes
3answers
153 views

Replace elements in matrix to make it symmetric using automated procedure

I am generating a matrix using (mat2 = Array[Subscript[a, ##] &, {4, 4}]) // MatrixForm but would like to force Mathematica to make it symmetric. Thereby I ...
2
votes
1answer
103 views

Force Mathematica to return numerical answer to (relatively) complicated differential function

I am trying to take the Laplacian of the LogDet of a 2x2 matrix that I call V\[ConjugateTranspose].V, and actually get a number out at the end. Why does Mathematica ...
0
votes
1answer
48 views

How to plot first and second row from matrix to a graph

i have this function: ...
0
votes
0answers
20 views

Manipulating nested matrices columnwise [duplicate]

I have a project that requires analyzing large volumes of excel sheets at the same time. I have been having trouble figuring out how to index the imported files and manipulating them. The way I am ...
0
votes
1answer
72 views

How to obtain a convergent solution iteratively for a linear system of equations

I am working on a problem that requires an iterative procedure to solve a linear system of equations, the system of equations in matrix form is: $$\underbrace{\begin{bmatrix} r_{11} & r_{12} ...
0
votes
1answer
42 views

Why Table is not giving me the same sequence for eigenvalues of matrix

Let consider a matrix and evaluate the time dependent eigenvalues M[t_]:={{Sin[t],Cos[t]},{t,t*t}}; e1[t_]:= Eigenvalues[M[t]] Now If I evaluate ...
1
vote
0answers
61 views

How to find Pauli matrices

I wanted to find the Pauli matrices, so i wrote down this code: z = {{a, b}, {c, d}} i = {{1, 0}, {0, 1}} Solve[z.z == i, {a, b, c, d}] and mathematica gave me ...
0
votes
1answer
31 views

Reduce Vector/Matrix mod N [closed]

If I have a vector such as below and want to reduce it mod a number, how can I do this? V = {{176}, {648}}; MatrixForm[V] MatrixForm[V, Modulus -> 26] Both ...
0
votes
0answers
108 views

Solving Symbolically Equations with Vectors and Matrices

I want to solve equations with vector variables and vector/matrix parameters symbolically. As a basic example I would like to be able to solve something like $[I-aG]x=b$ where $a,b \in \mathbb{R}^l$ ...
5
votes
4answers
498 views

Elegant mehod of generating this matrix?

Good evening, I need to determine an elegant (as possible) method of computing an nxn matrix below (the matrix shown is just a 16x16 example). I've been toying with For loops, Tables, Bands, ...
0
votes
1answer
202 views

Code efficiency improvement needed solving problem 499 in Project Euler

I am trying to solve https://projecteuler.net/problem=499 by constructing a transition matrix and finding its steady state. Here is my code: ...
1
vote
1answer
74 views

How to paste matrix to website and Email?

I tried to copy matrix from Mathematica to website, only end up with lots of garabge like this: ...
2
votes
2answers
52 views

How to edit a list according to the other list? [duplicate]

Gday guys. This problem troubles me, and I hope you can help me solve it. Say I have two random lists L1={{2},{5},{1},{0},{4},{7},{8}} L2={2,5,1,0,4,7,8} and ...
4
votes
2answers
144 views

How to check whether elements of a list meet a condition without generating the whole list first?

I have to find the number of elements satisfying a given condition from the set: Tuples[Tuples[Tuples[{0,1},n],n],m] The condition for $n=3,m=3$ is: ...
5
votes
2answers
537 views

The magic square function

There're some matrices that the sum of columns, sum of rows, and sum of diagonals are the same value. Here is an example: ...