Questions on the manipulation of matrices in Mathematica.

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1answer
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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
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1answer
197 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 ...
0
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0answers
33 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 ...
2
votes
1answer
68 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 ...
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0answers
40 views
1
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1answer
150 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 ...
1
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3answers
300 views

How to do equality check of a large matrix and get the corresponding index position?

Say I have a matrix A = 1000 x 5, and I want to compare it's first element (uppermost top left) to each of the 5 elements in the first column of matrix B of size 5 x 5. Whenever the first time the ...
1
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2answers
178 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 ...
2
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2answers
205 views

Diagonal minors of matrix

I need to calculate the minor of a matrix. I am going to use Mathematica example here, ...
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2answers
78 views

Matrix operation (simplify)

I had a $6\times 6$ matrix ...
2
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1answer
109 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: ...
3
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4answers
173 views

Restricting Numbers in a Matrix

I am generating a random N x N matrix, but with a certain restriction. What I'm trying to do is that when there's a "1" in a position, all neighboring positions must turn to "0" (so if [i,j] = 1, then ...
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0answers
87 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
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2answers
88 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 ...
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0answers
72 views

Calculate the matrix M such M.X=omega

I would like to determine the matrix M[3,3] such as M.X=w. ...
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5answers
1k views

Generating an Ulam spiral

An Ulam Spiral is quite an interesting construction, revealing unexpected features in the distribution of primes. Here is a related topic with one answer by Pinguin Dirk, who has provided one ...
1
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1answer
311 views

Can mathematica simplify an expression setting simplified answer equal to zero?

Basically I want to reduce something like: Subscript[P, 4] - Subscript[P, 5] == Subscript[R, 4, 5]* Subscript[i, 4, 5] when only one of them is known (...
4
votes
1answer
125 views

Eigensystem on HPC

I am submitting Mathematica jobs to an HPC. I have a large matrix that is a function of (x,y) and I am diagonalizing it for around 500 points in the plane. My initial idea was to request a node with ...
3
votes
3answers
176 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 ...
1
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2answers
112 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
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0answers
78 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 ...
4
votes
3answers
186 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
125 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 ...
1
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2answers
266 views

Get inverse of a matrix step-by-step [duplicate]

How can I get the inverse of a matrix step by step? An example: Given the matrix `{{8, 2}, {3, 2}}´, the result is {{$\frac{1}{5}$, -$\frac{1}{5}$}, {-$\frac{3}{10}$, $\frac{4}{5}$}}. But how can I ...
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0answers
21 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 ...
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0answers
90 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
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1answer
60 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 ...
5
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4answers
519 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, ...
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0answers
249 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 $a,b \in \mathbb{R}^l$ ...
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0answers
157 views

I need some GPU benchmark for Mathematica

I am considering to buy a GPU. I need to know two things: Is it possible to solve a system of differential equations using GPU and Mathematica's functions? I need to know how much faster would be ...
1
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0answers
114 views

NMaximize with matrix input

I defined function f[x_, fixed_] := {...}. Here x is an $M\times N$ matrix. I want to maximize $f$ with respect to $x$. I have ...
1
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1answer
339 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
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1answer
80 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
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2answers
63 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
182 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: ...
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0answers
44 views

Failure to evaluate functions of derivatives of Theta functions

I define a variant of the EllipticTheta function (multiplied by a constant factor) : ...
5
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3answers
680 views

Get Eigensystem to return orthogonal eigenvectors for Hermitian matrix

I have a Hermitian matrix, and I would like to get a list of orthogonal eigenvectors and corresponding eigenvalues. But when there are degenerate eigenvalues, sometimes Eigensystem/Eigenvectors ...
0
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0answers
117 views

Solving a system of equations involving partial derivatives for a wave

Before saying anything about the problem, I have checked "How to solve a system of partial differential equations?" yet it does not actually answers my question, as I have a 10x10 matrix to work on. ...
8
votes
7answers
303 views

Input a square matrix and return a list of the matrix entries read by antidiagonals

I have a square matrix: {{1,2,3},{4,5,6},{7,8,9}} and I want to get a list: {1,2,4,3,5,7}
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3answers
79 views

Form a matrix to have inequality elements

It looks like a silly question, but I could not find any answers online. Your help is greatly appreciated! Say I have two lists now. ...
1
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1answer
85 views

Wrong generalized eigenvalues of large numeric matrices

I've been working on a toy model of a variational method of a Hamiltonian H with an overlap matrix S. The point is that when H and S are small enough, Mathematica gives the correct eigenvalues (≈ ...
1
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2answers
72 views

Insert an element to AdjacencyGraph

I'm not able to insert an element to mine AdjacencyGraph. I suppose that i should modify my AdjcencyMatrix: ...
5
votes
1answer
257 views

Largest matrix size supported by Mathematica 10

I have need to store large square matrices in memory, some times sparse, some times not. I have used up to $2^{15}$ by $2^{15}$ as my upper bound so far, and Mathematica has handled it even if it took ...
1
vote
1answer
60 views

Defining a matrix with the symmetry Transpose[A(q)]=A(-q)

I am trying to construct a symbolic matrix with the following property- $$ \left(D_{3\times3}(q)\right)^T = D_{3\times3}(-q) $$ Note that for $q\in \mathbb{R}$, $D(q)$ would be hermitian. So far i ...
0
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2answers
95 views

Obtaining the relations of variables using diagonal matrices

I know this is too an elementary question, but I am a pathetic newbie in mathematica and I cannot find any answer by googling. What I want is obtaining some relations of unknown variables using their ...
4
votes
3answers
221 views

How can I suppress zero or nonzero values in a matrix?

So, if I have something like: F[IdentityMatrix[3] // MatrixForm, 1] I'd like F[] to display: $$\begin{pmatrix} 1 & ...