Questions on the manipulation of matrices in Mathematica.

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79 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 ...
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1answer
54 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 ...
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0answers
208 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
92 views

Replace part of a matrix

I have to generate a ne numbers of matrices with 1 and 0 and then replace some elements. ...
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4answers
514 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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1answer
306 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: ...
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1answer
76 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: ...
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2answers
61 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
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2answers
169 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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3answers
683 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: ...
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0answers
42 views

Failure to evaluate functions of derivatives of Theta functions

I define a variant of the EllipticTheta function (multiplied by a constant factor) : ...
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0answers
104 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. ...
4
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3answers
550 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 ...
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7answers
300 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
75 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. ...
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0answers
55 views

Does Mathematica support Laguerre Polynomials of Matrix Argument?

I am wondering whether Mathematica can also compute the Laguerre polynomials of matrix argument as the appear in multivariate statistics? For example, they appear in this paper here: ...
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1answer
78 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 (≈ ...
5
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1answer
217 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 ...
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1answer
57 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 ...
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1answer
96 views

Getting a part of a matrix Inverse for later use

I was trying to get an element of a matrix, and use in further computation of my program. Problem was that its not reading the value unless and until I specify it again. My code is: ...
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2answers
69 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: ...
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1answer
132 views

Why does Mathematica add Hold to the result of my user defined symbol?

In the code below I have defined a symbol that multiplies two block-matrices (I can't use the builtin Dot since Dot assumes that the matrix coefficients commute): ...
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1answer
67 views
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3answers
217 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 & ...
5
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4answers
265 views

Replacing parts of a matrix

I'm a beginner to Mathematica and to writing scripts in general. I'm currently trying to write a code that will take any element in a matrix higher than a certain threshold value n and set it equal to ...
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0answers
145 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 ...
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0answers
22 views

'MatrixForm' problem [duplicate]

I prefer to use 'MatrixForm' because the form looks better in matrix manipulation. But my current problem is that after the use of 'MatrixForm', subsequent matrix calculations like 'Det' or 'Inverse' ...
3
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1answer
144 views

Calculate efficiently an expensive hermitian matrix

I want to compute a matrix $M_{pq}$, for which the calculation of each coefficients $M_{pq} = f(p,q)$ is an expensive function. I know that my matrix is hermitian, so that $M_{qp} = M_{pq}^{*}$. As a ...
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0answers
106 views

How to speed up my code with constructing matrices

I have run this program for a long time to get the result for n = 2048(about 5hours) and no more result till now (can't run with n = 4096). I would know how to make it more efficient. Any help or ...
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2answers
181 views

Finding the Position of the Minimum Neighbor for Each Element in a Large Matrix

I have a large matrix ($6020\times 8452$), and I want to create a new matrix where the relative position of the minimum neighbor is each element in the matrix. For example, if I had the matrix ...
3
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1answer
112 views

Making table of matrix product and efficiency

I want to make a table in which each element is a matrix product: ...
4
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1answer
236 views

Polar Decomposition

I'm new to Mathematica 10 (half-a-month user). I'm looking for a function of polar decomposition but for now I cannot find it. Can anyone tell me about related functions. Thanks in advance.
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1answer
64 views

Computation time depends on the matrix elements!

Consider these two lists of matrices, matrix and matrix2: ...
16
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2answers
417 views

Why is my data 10 times slower than random data when doing matrix multiplication

I have some data generated from some program, and it appears that matrix multiplication on these data are about 10 times slower than on some random data: ...
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1answer
106 views

Efficient method of raising matrix to a variable power?

I have a $2 \times 2$ matrix $A$, where each element is a 12th order polynomial in a parameter $a$. I need to raise this matrix $A$ to the $-t/T$ power, where $T$ is a known scalar (for this ...
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2answers
104 views

specified matrix query

can you tell me a way (best?) to get a matrix with i=N,j=N dimensions (quadratic) according to the following rules: variables: N , M, n the diagonal must contain zeros it must contain exactly M ...
5
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1answer
219 views

Table and memory efficiency

Consider these two types of creating matrices: Table[Table[i*j,{i,1,10}],{j,1,10}] Table[i*j,{i,1,10},{j,1,10}] I want to know if there is any difference ...
4
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1answer
252 views

Fast matrix multiplication in MMA and GPU

Matlab multiplies two 3000by3000 matrix around 0.18s faster than MMA. While for just a few matrix multiplications the speed difference is not important, it becomes crucial when I want to do those ...
1
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1answer
645 views

How to take transpose of a one dimensional vector? [closed]

Why the two followings giving me same output? At least one should give me a row vector and another should give me a column vector. MatrixForm[u = {1 , 1, -1, 1}] MatrixForm[v = {{1}, {1}, {-1}, ...
5
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3answers
288 views

Multiplying block matrices

I have a 2*8 matrix A, and a 2*8*2 matrix B. So B[[1]] and B[[2]] are both 8*2 matrices. I need a neat way to multiply A by B so that the first list in the result is A.B[[1]] and the second list ...
2
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1answer
146 views

Rescaling and reorienting Matrix Plot axes

I have implemented a numeric Laplace Solver in C++ and am trying to graphically represent the validity of my method. I have outputted the grid from C++ and imported it into Mathematica to get the ...
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2answers
94 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 ...
3
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1answer
117 views

Print array with indices

Is there a single function that prints an array together with the indices? I know how to achieve this with Grid[{Range[n],array},Frame->All], but I vaguely ...
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0answers
82 views

solving singular matrix [duplicate]

Hello I have a matrix that is singular, and i wanted to use linear solve to solve it but that doesn't work with mathematica. The matrix given as a list looks like this: ...
0
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0answers
40 views

parsed matrix not deleting elements in adjusted matrix

I have a matrix that has been parsed to delete certain rows and columns, as well as delete certain elements on the diagonal on the matrix. The problem is that it does this in theory when i take the ...
0
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1answer
105 views

Matrix form of complex numbers [closed]

Complex numbers have matrix form. But some 2x2 matrices while differ, represent the same complex number. To compare complex numbers one has to transform the matrices to the form \begin{pmatrix} a ...
2
votes
1answer
119 views

Design matrix rank does not match

I'm attempting to fit a linear model and Mathematica returns the error message: "The rank of the design matrix 9 is less than the number of terms 10 in the model. The model and results based upon it ...
4
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2answers
124 views

How to reflect the entries of a square matrix about its anti-diagonal?

I need help with writing the mathematica code to reflect the entries of a square matrix about its anti-diagonal. I know to do it about the main diagonal using ...
0
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1answer
66 views

Why is there a seeming discrepancy with the expression Cofactor?

I was trying to find out the cofactors of a square matrix. Then I came across the command Cofactor in Combinatorica package. ...
2
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1answer
172 views

Computing with matrix differential operators

I am looking the achieve a working set of Mathematica functions that would allow me to take products, commutators, etc. of (2x2) matrix differential operators and apply them to vector-valued functions ...